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Bucher ML, Dunn AR, Bradner JM, Egerton KS, Burkett JP, Johnson MA, Miller GW. Synaptic vesicle glycoprotein 2C enhances vesicular storage of dopamine and counters dopaminergic toxicity. Eur J Neurosci 2024; 59:2483-2501. [PMID: 38532289 DOI: 10.1111/ejn.16311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 02/14/2024] [Accepted: 02/22/2024] [Indexed: 03/28/2024]
Abstract
Dopaminergic neurons of the substantia nigra exist in a persistent state of vulnerability resulting from high baseline oxidative stress, high-energy demand, and broad unmyelinated axonal arborisations. Impairments in the storage of dopamine compound this stress because of cytosolic reactions that transform the vital neurotransmitter into an endogenous neurotoxicant, and this toxicity is thought to contribute to the dopamine neuron degeneration that occurs Parkinson's disease. We have previously identified synaptic vesicle glycoprotein 2C (SV2C) as a modifier of vesicular dopamine function, demonstrating that genetic ablation of SV2C in mice results in decreased dopamine content and evoked dopamine release in the striatum. Here, we adapted a previously published in vitro assay utilising false fluorescent neurotransmitter 206 (FFN206) to visualise how SV2C regulates vesicular dopamine dynamics and determined that SV2C promotes the uptake and retention of FFN206 within vesicles. In addition, we present data indicating that SV2C enhances the retention of dopamine in the vesicular compartment with radiolabelled dopamine in vesicles isolated from immortalised cells and from mouse brain. Further, we demonstrate that SV2C enhances the ability of vesicles to store the neurotoxicant 1-methyl-4-phenylpyridinium (MPP+) and that genetic ablation of SV2C results in enhanced 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced vulnerability in mice. Together, these findings suggest that SV2C functions to enhance vesicular storage of dopamine and neurotoxicants and helps maintain the integrity of dopaminergic neurons.
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Affiliation(s)
- Meghan L Bucher
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York, USA
| | - Amy R Dunn
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
- The Jackson Laboratory, Bar Harbor, Maine, USA
| | - Joshua M Bradner
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York, USA
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
- AbbVie CRC, Cambridge, Massachusetts, USA
| | - Kristen Stout Egerton
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
- School of Education and Health Sciences, North Central College, Naperville, Illinois, USA
| | - James P Burkett
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
- Department of Neurosciences, University of Toledo College of Medicine, Toledo, Ohio, USA
| | - Michelle A Johnson
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
- College of Arts and Sciences, Oberlin College, Oberlin, Ohio, USA
| | - Gary W Miller
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York, USA
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
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2
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Bu M, Follett J, Deng I, Tatarnikov I, Wall S, Guenther D, Maczis M, Wimsatt G, Milnerwood A, Moehle MS, Khoshbouei H, Farrer MJ. Inhibition of LRRK2 kinase activity rescues deficits in striatal dopamine physiology in VPS35 p.D620N knock-in mice. NPJ Parkinsons Dis 2023; 9:167. [PMID: 38110354 PMCID: PMC10728137 DOI: 10.1038/s41531-023-00609-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Accepted: 11/24/2023] [Indexed: 12/20/2023] Open
Abstract
Dysregulation of dopamine neurotransmission profoundly affects motor, motivation and learning behaviors, and can be observed during the prodromal phase of Parkinson's disease (PD). However, the mechanism underlying these pathophysiological changes remains to be elucidated. Mutations in vacuolar protein sorting 35 (VPS35) and leucine-rich repeat kinase 2 (LRRK2) both lead to autosomal dominant PD, and VPS35 and LRRK2 may physically interact to govern the trafficking of synaptic cargos within the endo-lysosomal network in a kinase-dependent manner. To better understand the functional role of VPS35 and LRRK2 on dopamine physiology, we examined Vps35 haploinsufficient (Haplo) and Vps35 p.D620N knock-in (VKI) mice and how their behavior, dopamine kinetics and biochemistry are influenced by LRRK2 kinase inhibitors. We found Vps35 p.D620N significantly elevates LRRK2-mediated phosphorylation of Rab10, Rab12 and Rab29. In contrast, Vps35 haploinsufficiency reduces phosphorylation of Rab12. While striatal dopamine transporter (DAT) expression and function is similarly impaired in both VKI and Haplo mice, that physiology is normalized in VKI by treatment with the LRRK2 kinase inhibitor, MLi-2. As a corollary, VKI animals show a significant increase in amphetamine induced hyperlocomotion, compared to Haplo mice, that is also abolished by MLi-2. Taken together, these data show Vps35 p.D620N confers a gain-of-function with respect to LRRK2 kinase activity, and that VPS35 and LRRK2 functionally interact to regulate DAT function and striatal dopamine transmission.
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Affiliation(s)
- Mengfei Bu
- Department of Neurology, University of Florida, Gainesville, FL, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Jordan Follett
- Department of Neurology, University of Florida, Gainesville, FL, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Isaac Deng
- Department of Neurology, University of Florida, Gainesville, FL, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Igor Tatarnikov
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Shannon Wall
- Department of Neurology, University of Florida, Gainesville, FL, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Dylan Guenther
- Department of Neurology, University of Florida, Gainesville, FL, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Melissa Maczis
- Department of Neurology, University of Florida, Gainesville, FL, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Genevieve Wimsatt
- Department of Neurology, University of Florida, Gainesville, FL, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Austen Milnerwood
- Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Mark S Moehle
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL, USA
| | - Habibeh Khoshbouei
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Matthew J Farrer
- Department of Neurology, University of Florida, Gainesville, FL, USA.
- McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
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3
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Alwindi M, Bizanti A. Vesicular monoamine transporter (VMAT) regional expression and roles in pathological conditions. Heliyon 2023; 9:e22413. [PMID: 38034713 PMCID: PMC10687066 DOI: 10.1016/j.heliyon.2023.e22413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 09/28/2023] [Accepted: 11/10/2023] [Indexed: 12/02/2023] Open
Abstract
Vesicular monoamine transporters (VMATs) are key regulators of neurotransmitter release responsible for controlling numerous physiological, cognitive, emotional, and behavioral functions. They represent important therapeutic targets for numerous pathological conditions. There are two isoforms of VMAT transporter proteins that function as secondary active transporters into the vesicle for storage and release via exocytosis: VMAT1 (SLC18A1) and VMAT2 (SLC18A2) which differ in their function, quantity, and regional expression. VMAT2 has gained considerable interest as a therapeutic target and diagnostic marker. Inhibitors of VMAT2 have been used as an effective therapy for a range of pathological conditions. Additionally, the functionality and phenotypic classification of classical and nonclassical catecholaminergic neurons are identified by the presence of VMAT2 in catecholaminergic neurons. Dysregulation of VMAT2 is also implicated in many neuropsychiatric diseases. Despite the complex role of VMAT2, many aspects of its function remain unclear. Therefore, our aim is to expand our knowledge of the role of VMAT with a special focus on VMAT2 in different systems and cellular pathways which may potentially facilitate development of novel, more specific therapeutic targets. The current review provides a summary demonstrating the mechanism of action of VMAT, its functional role, and its contribution to disease progression and utilization as therapeutic targets.
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Affiliation(s)
- Malik Alwindi
- St George's University Hospital, London SW17 0QT, United Kingdom
| | - Ariege Bizanti
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32816, USA
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Boyd SL, Kuhn NC, Patterson JR, Stoll AC, Zimmerman SA, Kolanowski MR, Neubecker JJ, Luk KC, Ramsson ES, Sortwell CE, Bernstein AI. Developmental exposure to the Parkinson's disease-associated organochlorine pesticide dieldrin alters dopamine neurotransmission in α-synuclein pre-formed fibril (PFF)-injected mice. Toxicol Sci 2023; 196:99-111. [PMID: 37607008 PMCID: PMC10613968 DOI: 10.1093/toxsci/kfad086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023] Open
Abstract
Parkinson's disease (PD) is the fastest-growing neurological disease worldwide, with increases outpacing aging and occurring most rapidly in recently industrialized areas, suggesting a role of environmental factors. Epidemiological, post-mortem, and mechanistic studies suggest that persistent organic pollutants, including the organochlorine pesticide dieldrin, increase PD risk. In mice, developmental dieldrin exposure causes male-specific exacerbation of neuronal susceptibility to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and synucleinopathy. Specifically, in the α-synuclein (α-syn) pre-formed fibril (PFF) model, exposure leads to increased deficits in striatal dopamine (DA) turnover and motor deficits on the challenging beam. Here, we hypothesized that alterations in DA handling contribute to the observed changes and assessed vesicular monoamine transporter 2 (VMAT2) function and DA release in this dieldrin/PFF 2-hit model. Female C57BL/6 mice were exposed to 0.3 mg/kg dieldrin or vehicle every 3 days by feeding, starting at 8 weeks of age and continuing throughout breeding, gestation, and lactation. Male offspring from independent litters underwent unilateral, intrastriatal injections of α-syn PFFs at 12 weeks of age, and vesicular 3H-DA uptake assays and fast-scan cyclic voltammetry were performed 4 months post-PFF injection. Dieldrin-induced an increase in DA release in striatal slices in PFF-injected animals, but no change in VMAT2 activity. These results suggest that developmental dieldrin exposure increases a compensatory response to synucleinopathy-triggered striatal DA loss. These findings are consistent with silent neurotoxicity, where developmental exposure to dieldrin primes the nigrostriatal striatal system to have an exacerbated response to synucleinopathy in the absence of observable changes in typical markers of nigrostriatal dysfunction and degeneration.
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Affiliation(s)
- Sierra L Boyd
- Department of Translational Neuroscience, College of Human Medicine, Michigan State University, Grand Rapids, MI, USA
| | - Nathan C Kuhn
- Department of Translational Neuroscience, College of Human Medicine, Michigan State University, Grand Rapids, MI, USA
| | - Joseph R Patterson
- Department of Translational Neuroscience, College of Human Medicine, Michigan State University, Grand Rapids, MI, USA
| | - Anna C Stoll
- Department of Translational Neuroscience, College of Human Medicine, Michigan State University, Grand Rapids, MI, USA
| | - Sydney A Zimmerman
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI, USA
| | - Mason R Kolanowski
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI, USA
| | - Joseph J Neubecker
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI, USA
| | - Kelvin C Luk
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, University of Pennsylvania, Philadelphia, PA, USA
| | - Eric S Ramsson
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI, USA
| | - Caryl E Sortwell
- Department of Translational Neuroscience, College of Human Medicine, Michigan State University, Grand Rapids, MI, USA
| | - Alison I Bernstein
- Department of Translational Neuroscience, College of Human Medicine, Michigan State University, Grand Rapids, MI, USA
- Department of Pharmacology and Toxicology, School of Pharmacy, Rutgers University, Piscataway, NJ, USA
- Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ, USA
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5
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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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Lee H, Kim H, Choi D, Ko EN, Choi J, Seo Y, Lee S, Kim S, Jung S, Kim M, Kang D, Im C, Bae G, Jung S, Kwon O. Dopaminergic cell protection and alleviation of neuropsychiatric disease symptoms by VMAT2 expression through the class I HDAC inhibitor TC-H 106. Pharmacol Res Perspect 2023; 11:e01135. [PMID: 37740715 PMCID: PMC10517640 DOI: 10.1002/prp2.1135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 08/24/2023] [Accepted: 08/24/2023] [Indexed: 09/25/2023] Open
Abstract
The importance of vesicular monoamine transporter 2 (VMAT2) in dopamine regulation, which is considered crucial for neuropsychiatric disorders, is currently being studied. Moreover, the development of disease treatments using histone deacetylase (HDAC) inhibitors (HDACi) is actively progressing in various fields. Recently, research on the possibility of regulating neuropsychiatric disorders has been conducted. In this study, we evaluated whether VMAT2 expression increased by an HDACi can fine-tune neuropsychotic behavior, such as attention deficit hyperactivity disorder (ADHD) and protect against the cell toxicity through oxidized dopamine. First, approximately 300 candidate HDACi compounds were added to the SH-SY5Y dopaminergic cell line to identify the possible changes in the VMAT2 expression levels, which were measured using quantitative polymerase chain reaction. The results demonstrated, that treatment with pimelic diphenylamide 106 (TC-H 106), a class I HDACi, increased VMAT2 expression in both the SH-SY5Y cells and mouse brain. The increased VMAT2 expression induced by TC-H 106 alleviated the cytotoxicity attributed to 6-hydroxydopamine (6-OHDA) or 1-methyl-4-phenylpyridinium (MPP+ ) and free dopamine treatment. Moreover, dopamine concentrations, both intracellularly and in the synaptosomes, were significantly elevated by increased VMAT2 expression. These results suggest that dopamine concentration regulation by VMAT2 expression induced by TC-H 106 could alter several related behavioral aspects that was confirmed by attenuation of hyperactivity and impulsivity, which were major characteristics of animal model showing ADHD-like behaviors. These results indicate that HDACi-increased VMAT2 expression offers sufficient protections against dopaminergic cell death induced by oxidative stress. Thus, the epigenetic approach could be considered as therapeutic candidate for neuropsychiatric disease regulation.
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Affiliation(s)
- Heejin Lee
- New Drug Development Center, K‐MedihubDaeguKorea
| | - Hye‐Ji Kim
- Department of Physiology, School of MedicineJeju National UniversityJejuKorea
| | | | - Eu n.‐A. Ko
- Department of Physiology, School of MedicineJeju National UniversityJejuKorea
| | | | - Yohan Seo
- New Drug Development Center, K‐MedihubDaeguKorea
| | - Sion Lee
- New Drug Development Center, K‐MedihubDaeguKorea
| | | | - Sejin Jung
- New Drug Development Center, K‐MedihubDaeguKorea
| | - Minwoo Kim
- New Drug Development Center, K‐MedihubDaeguKorea
| | - Dongwan Kang
- New Drug Development Center, K‐MedihubDaeguKorea
| | | | - Gi‐Hun Bae
- New Drug Development Center, K‐MedihubDaeguKorea
| | - Sung‐Cherl Jung
- Department of Physiology, School of MedicineJeju National UniversityJejuKorea
| | - Oh‐Bin Kwon
- New Drug Development Center, K‐MedihubDaeguKorea
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7
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Zhou ZD, Yi LX, Wang DQ, Lim TM, Tan EK. Role of dopamine in the pathophysiology of Parkinson's disease. Transl Neurodegener 2023; 12:44. [PMID: 37718439 PMCID: PMC10506345 DOI: 10.1186/s40035-023-00378-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 09/08/2023] [Indexed: 09/19/2023] Open
Abstract
A pathological feature of Parkinson's disease (PD) is the progressive loss of dopaminergic neurons and decreased dopamine (DA) content in the substantia nigra pars compacta in PD brains. DA is the neurotransmitter of dopaminergic neurons. Accumulating evidence suggests that DA interacts with environmental and genetic factors to contribute to PD pathophysiology. Disturbances of DA synthesis, storage, transportation and metabolism have been shown to promote neurodegeneration of dopaminergic neurons in various PD models. DA is unstable and can undergo oxidation and metabolism to produce multiple reactive and toxic by-products, including reactive oxygen species, DA quinones, and 3,4-dihydroxyphenylacetaldehyde. Here we summarize and highlight recent discoveries on DA-linked pathophysiologic pathways, and discuss the potential protective and therapeutic strategies to mitigate the complications associated with DA.
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Affiliation(s)
- Zhi Dong Zhou
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore.
- Signature Research Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School Singapore, 8 College Road, Singapore, 169857, Singapore.
| | - Ling Xiao Yi
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore
| | - Dennis Qing Wang
- Department of Neurology, Zhujiang Hospital, Southern Medical University, Guangzhou, 510280, China
| | - Tit Meng Lim
- Department of Biological Science, National University of Singapore, Singapore, 119077, Singapore
| | - Eng King Tan
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore.
- Department of Neurology, Singapore General Hospital, Outram Road, Singapore, 169608, Singapore.
- Signature Research Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School Singapore, 8 College Road, Singapore, 169857, Singapore.
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8
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Iannitelli AF, Weinshenker D. Riddles in the dark: Decoding the relationship between neuromelanin and neurodegeneration in locus coeruleus neurons. Neurosci Biobehav Rev 2023; 152:105287. [PMID: 37327835 PMCID: PMC10523397 DOI: 10.1016/j.neubiorev.2023.105287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/11/2023] [Accepted: 06/13/2023] [Indexed: 06/18/2023]
Abstract
The noradrenergic locus coeruleus (LC) is among the first regions of the brain affected by pathology in both Alzheimer's disease (AD) and Parkinson's disease (PD), but the reasons for this selective vulnerability are not completely understood. Several features of LC neurons have been proposed as contributing factors to this dysfunction and degeneration, and this review will focus on the presence of neuromelanin (NM). NM is a dark pigment unique to catecholaminergic cells that is formed of norepinephrine (NE) and dopamine (DA) metabolites, heavy metals, protein aggregates, and oxidated lipids. We cover what is currently known about NM and the limitations of historical approaches, then discuss the new human tyrosinase (hTyr) model of NM production in rodent catecholamine cells in vivo that offers unique opportunities for studying its neurobiology, neurotoxicity, and potential of NM-based therapeutics for treating neurodegenerative disease.
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Affiliation(s)
- Alexa F Iannitelli
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - David Weinshenker
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA.
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9
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Pilski A, Graves SM. Repeated Methamphetamine Administration Results in Axon Loss Prior to Somatic Loss of Substantia Nigra Pars Compacta and Locus Coeruleus Neurons in Male but Not Female Mice. Int J Mol Sci 2023; 24:13039. [PMID: 37685846 PMCID: PMC10487759 DOI: 10.3390/ijms241713039] [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: 07/29/2023] [Revised: 08/17/2023] [Accepted: 08/19/2023] [Indexed: 09/10/2023] Open
Abstract
Methamphetamine (meth) is a neurotoxic psychostimulant that increases monoamine oxidase (MAO)-dependent mitochondrial oxidant stress in axonal but not somatic compartments of substantia nigra pars compacta (SNc) and locus coeruleus (LC) neurons. Chronic meth administration results in the degeneration of SNc and LC neurons in male mice, and MAO inhibition is neuroprotective, suggesting that the deleterious effects of chronic meth begin in axons before advancing to the soma of SNc and LC neurons. To test this hypothesis, mice were administered meth (5 mg/kg) for 14, 21, or 28 days, and SNc and LC axonal lengths and numbers of neurons were quantified. In male mice, the SNc and LC axon lengths decreased with 14, 21, and 28 days of meth, whereas somatic loss was only observed after 28 days of meth; MAO inhibition (phenelzine; 20 mg/kg) prevented axonal and somatic loss of SNc and LC neurons. In contrast, chronic (28-day) meth had no effect on the axon length or numbers of SNc or LC neurons in female mice. The results demonstrate that repeated exposure to meth produces SNc and LC axonal deficits prior to somatic loss in male subjects, consistent with a dying-back pattern of degeneration, whereas female mice are resistant to chronic meth-induced degeneration.
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Affiliation(s)
| | - Steven M. Graves
- Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA;
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10
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Bucher ML, Dunn AR, Bradner JM, Egerton KS, Burkett JP, Johnson MA, Miller GW. Synaptic vesicle glycoprotein 2C enhances vesicular storage of dopamine and counters dopaminergic toxicity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.26.546143. [PMID: 37425736 PMCID: PMC10326994 DOI: 10.1101/2023.06.26.546143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Dopaminergic neurons of the substantia nigra exist in a persistent state of vulnerability resulting from high baseline oxidative stress, high energy demand, and broad unmyelinated axonal arborizations. Impairments in the storage of dopamine compound this stress due to cytosolic reactions that transform the vital neurotransmitter into an endogenous neurotoxicant, and this toxicity is thought to contribute to the dopamine neuron degeneration that occurs Parkinson's disease. We have previously identified synaptic vesicle glycoprotein 2C (SV2C) as a modifier of vesicular dopamine function, demonstrating that genetic ablation of SV2C in mice results in decreased dopamine content and evoked dopamine release in the striatum. Here, we adapted a previously published in vitro assay utilizing false fluorescent neurotransmitter 206 (FFN206) to visualize how SV2C regulates vesicular dopamine dynamics and determined that SV2C promotes the uptake and retention of FFN206 within vesicles. In addition, we present data indicating that SV2C enhances the retention of dopamine in the vesicular compartment with radiolabeled dopamine in vesicles isolated from immortalized cells and from mouse brain. Further, we demonstrate that SV2C enhances the ability of vesicles to store the neurotoxicant 1-methyl-4-phenylpyridinium (MPP+) and that genetic ablation of SV2C results in enhanced 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced vulnerability in mice. Together, these findings suggest that SV2C functions to enhance vesicular storage of dopamine and neurotoxicants, and helps maintain the integrity of dopaminergic neurons.
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Affiliation(s)
- Meghan L Bucher
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Amy R Dunn
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - Joshua M Bradner
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - Kristen Stout Egerton
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - James P Burkett
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - Michelle A Johnson
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - Gary W Miller
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10031, USA
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11
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Discontinuation of methylphenidate after long-term exposure in nonhuman primates. Neurotoxicol Teratol 2023; 97:107173. [PMID: 36893929 DOI: 10.1016/j.ntt.2023.107173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 01/19/2023] [Accepted: 03/03/2023] [Indexed: 03/09/2023]
Abstract
Attention-deficit hyperactivity disorder (ADHD) is a common human neurobehavioral disorder that usually begins in early childhood. Methylphenidate (MPH) has been used extensively as a first-line medicine for the treatment of ADHD. Since ADHD is often diagnosed in early childhood and can persist for the entire lifespan, individuals may take MPH for many years. Given that in the course of one's lifetime a person may stop taking MPH for periods of time, or may implement lifestyle changes that may reduce the need for MPH entirely, it is important to understand how cessation of MPH affects the adult brain following long-term use of MPH. The blockage of the dopamine transporter (DAT) and the norepinephrine transporter (NET) by MPH may help with ADHD symptoms by boosting monoamine levels in the synapse. In the present study, microPET/CT was used to investigate possible neurochemical alterations in the cerebral dopamine system after cessation of long-term MPH administration in nonhuman primates. MicroPET/CT images were collected from adult male rhesus monkeys 6 months after they stopped receiving vehicle or MPH following 12 years of chronic treatment. The neurochemical status of brain dopaminergic systems was evaluated using the vesicular monoamine transporter 2 (VMAT2) ligand [18F]-AV-133 and a tracer for imaging dopamine subtype 2 (D2) and serotonin subfamily 2 (5HT2) receptors, [18F]-FESP. Each tracer was injected intravenously and ten minutes later microPET/CT images were obtained over 120 min. The binding potential (BP) of each tracer in the striatum was obtained using the Logan reference tissue model with the cerebellar cortex time activity curve (TAC) as an input function. Brain metabolism was also evaluated using microPET/CT images of [18F]-FDG. [18F]-FDG was injected intravenously, and ten minutes later, microPET/CT images were obtained over 120 min. Radiolabeled tracer accumulation in regions of interest (ROIs) in the prefrontal cortex, temporal cortex, striatum, and cerebellum were converted into standard uptake values (SUVs). Compared to the vehicle control group, the BPs of [18F] AV-133 and [18F]-FESP in the striatum were not significantly altered in MPH treated groups. Additionally, no significant differences were detected in the SUVs of [18F]-FDG in the MPH treated group compared with control. This study demonstrates that 6 months after cessation of long-term, chronic MPH treatment, there are no significant neurochemical or neural metabolic changes in the central nervous system (CNS) of non-human primates (NHPs) and suggests that microPET imaging is helpful in assessing the status of biomarkers of neurochemical processes linked to chronic CNS drug exposure. (Supported by NCTR).
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12
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Liu C, Fang Y, Tang J, Chen Z. Derivatization of dihydrotetrabenazine for technetium-99m labelling towards a radiotracer targeting vesicular monoamine transporter 2. ARAB J CHEM 2023. [DOI: 10.1016/j.arabjc.2023.104572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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13
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Biochemical Neuroadaptations in the Rat Striatal Dopaminergic System after Prolonged Exposure to Methamphetamine Self-Administration. Int J Mol Sci 2022; 23:ijms231710092. [PMID: 36077488 PMCID: PMC9456063 DOI: 10.3390/ijms231710092] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 08/29/2022] [Accepted: 09/01/2022] [Indexed: 11/17/2022] Open
Abstract
Perturbations in striatal dopamine (DA) homeostasis might underlie the behavioral and pathobiological consequences of METH use disorder in humans. To identify potential consequences of long-term METH exposure, we modeled the adverse consequence DSM criterion of substance use disorders by giving footshocks to rats that had escalated their intake of METH during a drug self-administration procedure. Next, DA D1 receptor antagonist, SCH23390 was injected. Thereafter, rats were euthanized to measure several indices of the striatal dopaminergic system. Footshocks split the METH rats into two phenotypes: (i) shock-sensitive that decreased their METH-intake and (ii) shock-resistant that continued their METH intake. SCH23390 caused substantial dose-dependent reduction of METH taking in both groups. Stopping SCH23390 caused re-emergence of compulsive METH taking in shock-resistant rats. Compulsive METH takers also exhibited greater incubation of METH seeking than non-compulsive rats during withdrawal from METH SA. Analyses of DA metabolism revealed non-significant decreases (about 35%) in DA levels in resistant and sensitive rats. However, striatal contents of the deaminated metabolites, DOPAL and DOPAC, were significantly increased in sensitive rats. VMAT2 and DAT protein levels were decreased in both phenotypes. Moreover, protein expression levels of the D1-like DA receptor, D5R, and D2-like DA receptors, D3R and D4R, were significantly decreased in the compulsive METH takers. Our results parallel findings in post-mortem striatal tissues of human METH users who develop Parkinsonism after long-term METH intake and support the use of this model to investigate potential therapeutic interventions for METH use disorder.
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Du Y, Choi S, Pilski A, Graves SM. Differential vulnerability of locus coeruleus and dorsal raphe neurons to chronic methamphetamine-induced degeneration. Front Cell Neurosci 2022; 16:949923. [PMID: 35936499 PMCID: PMC9354074 DOI: 10.3389/fncel.2022.949923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 07/04/2022] [Indexed: 12/15/2022] Open
Abstract
Methamphetamine (meth) increases monoamine oxidase (MAO)-dependent mitochondrial stress in axons of substantia nigra pars compacta (SNc), and ventral tegmental area (VTA) dopamine neurons. Chronic administration of meth results in SNc degeneration and MAO inhibition is neuroprotective, whereas, the VTA is resistant to degeneration. This differential vulnerability is attributed, at least in part, to the presence of L-type Ca2+ channel-dependent mitochondrial stress in SNc but not VTA dopamine neurons. MAO is also expressed in other monoaminergic neurons such as noradrenergic locus coeruleus (LC) and serotonergic dorsal raphe (DR) neurons. The impact of meth on mitochondrial stress in LC and DR neurons is unknown. In the current study we used a genetically encoded redox biosensor to investigate meth-induced MAO-dependent mitochondrial stress in LC and DR neurons. Similar to SNc and VTA neurons, meth increased MAO-dependent mitochondrial stress in axonal but not somatic compartments of LC norepinephrine and DR serotonin neurons. Chronic meth administration (5 mg/kg; 28-day) resulted in degeneration of LC neurons and MAO inhibition was neuroprotective whereas DR neurons were resistant to degeneration. Activating L-type Ca2+ channels increased mitochondrial stress in LC but not DR axons and inhibiting L-type Ca2+ channels in vivo with isradipine prevented meth-induced LC degeneration. These data suggest that similar to recent findings in SNc and VTA dopamine neurons, the differential vulnerability between LC and DR neurons can be attributed to the presence of L-type Ca2+ channel-dependent mitochondrial stress. Taken together, the present study demonstrates that both meth-induced MAO- and L-type Ca2+ channel-dependent mitochondrial stress are necessary for chronic meth-induced neurodegeneration.
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15
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Du Y, Lee YB, Graves SM. Chronic methamphetamine-induced neurodegeneration: Differential vulnerability of ventral tegmental area and substantia nigra pars compacta dopamine neurons. Neuropharmacology 2021; 200:108817. [PMID: 34610287 PMCID: PMC8556701 DOI: 10.1016/j.neuropharm.2021.108817] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/17/2021] [Accepted: 09/27/2021] [Indexed: 11/17/2022]
Abstract
Methamphetamine (meth) increases monoamine oxidase (MAO)-dependent mitochondrial stress in substantia nigra pars compacta (SNc) axons; chronic administration produces SNc degeneration that is prevented by MAO inhibition suggesting that MAO-dependent axonal mitochondrial stress is a causal factor. To test whether meth similarly increases mitochondrial stress in ventral tegmental area (VTA) axons, we used a genetically encoded redox biosensor to assess mitochondrial stress ex vivo. Meth increased MAO-dependent mitochondrial stress in both SNc and VTA axons. However, despite having the same meth-induced stress as SNc neurons, VTA neurons were resistant to chronic meth-induced degeneration indicating that meth-induced MAO-dependent mitochondrial stress in axons was necessary but not sufficient for degeneration. To determine whether L-type Ca2+ channel-dependent stress differentiates SNc and VTA axons, as reported in the soma, the L-type Ca2+ channel activator Bay K8644 was used. Opening L-type Ca2+ channels increased axonal mitochondrial stress in SNc but not VTA axons. To first determine whether mitochondrial stress was necessary for SNc degeneration, mice were treated with the mitochondrial antioxidant mitoTEMPO. Chronic meth-induced SNc degeneration was prevented by mitoTEMPO thereby confirming the necessity of mitochondrial stress. Similar to results with the antioxidant, both MAO inhibition and L-type Ca2+ channel inhibition also prevented SNc degeneration. Taken together the presented data demonstrate that both MAO- and L-type Ca2+ channel-dependent mitochondrial stress is necessary for chronic meth-induced degeneration.
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Affiliation(s)
- Yijuan Du
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - You Bin Lee
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Steven M Graves
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA.
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16
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Graves SM, Schwarzschild SE, Tai RA, Chen Y, Surmeier DJ. Mitochondrial oxidant stress mediates methamphetamine neurotoxicity in substantia nigra dopaminergic neurons. Neurobiol Dis 2021; 156:105409. [PMID: 34082123 PMCID: PMC8686177 DOI: 10.1016/j.nbd.2021.105409] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 05/12/2021] [Accepted: 05/28/2021] [Indexed: 12/14/2022] Open
Abstract
Methamphetamine abuse is associated with an increased risk of developing Parkinson's disease (PD). Recently, it was found that methamphetamine increases mitochondrial oxidant stress in substantia nigra pars compacta (SNc) dopaminergic neurons by releasing vesicular dopamine (DA) and stimulating mitochondrially-anchored monoamine oxidase (MAO). As mitochondrial oxidant stress is widely thought to be a driver of SNc degeneration in PD, these observations provide a potential explanation for the epidemiological linkage. To test this hypothesis, mice were administered methamphetamine (5 mg/kg) for 28 consecutive days with or without pretreatment with an irreversible MAO inhibitor. Chronic methamphetamine administration resulted in the degeneration of SNc dopaminergic neurons and this insult was blocked by pretreatment with a MAO inhibitor - confirming the linkage between methamphetamine, MAO and SNc degeneration. To determine if shorter bouts of consumption were as damaging, mice were given methamphetamine for two weeks and then studied. Methamphetamine treatment elevated both axonal and somatic mitochondrial oxidant stress in SNc dopaminergic neurons, was associated with a modest but significant increase in firing frequency, and caused degeneration after drug cessation. While axonal stress was sensitive to MAO inhibition, somatic stress was sensitive to Cav1 Ca2+ channel inhibition. Inhibiting either MAO or Cav1 Ca2+ channels after methamphetamine treatment attenuated subsequent SNc degeneration. Our results not only establish a mechanistic link between methamphetamine abuse and PD, they point to pharmacological strategies that could lessen PD risk for patients with a methamphetamine use disorder.
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Affiliation(s)
- Steven M Graves
- Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, United States of America
| | - Sarah E Schwarzschild
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America
| | - Rex A Tai
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America
| | - Yu Chen
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America
| | - D James Surmeier
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, United States of America.
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17
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Zhang X, Talpos J, Berridge MS, Apana SM, Slikker W, Wang C, Paule MG. MicroPET/CT assessment of neurochemical effects in the brain after long-term methylphenidate treatment in nonhuman primates. Neurotoxicol Teratol 2021; 87:107017. [PMID: 34265415 DOI: 10.1016/j.ntt.2021.107017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/07/2021] [Accepted: 07/09/2021] [Indexed: 01/23/2023]
Abstract
Methylphenidate (MPH) is a psychostimulant approved by the FDA to treatment Attention-Deficit Hyperactivity Disorder (ADHD). MPH is believed to exert its pharmacological effects via preferential blockade of the dopamine transporter (DAT) and the norepinephrine transporter (NET), resulting in increased monoamine levels in the synapse. We used a quantitative non-invasive PET imaging technique to study the effects of long-term methylphenidate use on the central nervous system (CNS). We conducted microPET/CT scans on young adult male rhesus monkeys to monitor changes in the dopaminergic system. We used [18F] AV-133, a ligand for the vesicular monoamine transporter 2 (VMAT2), and [18F]FESP a ligand for the D2 and 5HT2 receptors. In this study we evaluated the effects if chronic MPH treatment in the nonhuman primates (NHP). Two-year-old, male rhesus monkeys were orally administered MPH diluted in the electrolyte replenisher, Prang, twice a day, five days per week (M-F) over an 8-year period. The dose of MPH was gradually escalated from 0.15 mg/kg initially to 2.5 mg/kg/dose for the low dose group, and 1.5 mg/kg to 12.5 mg/kg/dose for the high dose group (Rodriguez et al., 2010). Scans were performed on Mondays, about 60 h after their last treatment, to avoid the acute effects of MPH. Tracers were injected intravenously ten minutes before microPET/CT scanning. Sessions lasted about 120 min. The Logan reference tissue model was used to determine the Binding Potential (BP) of each tracer in the striatum with the cerebellar cortex time activity curve as an input function. Both MP treatment groups had a lower [18F] AV-133 BP, although this failed to reach statistical significance. MPH treatment did not have a significant effect on The BP of [18F] FESP in the striatum. Long-term administration of MPH did not significant change any of the marker of monoamine function used here. These data suggest that, despite lingering concerns, long-term use of methylphenidate does not negatively impact monoamine function. This study also demonstrates that microPET imaging can distinguish differences in binding potentials of a variety of radiotracers in the CNS of NHPs. This approach may provide minimally-invasive biomarkers of neurochemical processes associated with chronic exposure to CNS medications. (Supported by NCTR).
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Affiliation(s)
- X Zhang
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, United States of America.
| | - J Talpos
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, United States of America
| | - M S Berridge
- 3D Imaging, LLC, Little Rock, AR 72113 and University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States of America
| | - S M Apana
- 3D Imaging, LLC, Little Rock, AR 72113 and University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States of America
| | - W Slikker
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, United States of America
| | - C Wang
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, United States of America
| | - M G Paule
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, United States of America
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18
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Vecchio LM, Sullivan P, Dunn AR, Bermejo MK, Fu R, Masoud ST, Gregersen E, Urs NM, Nazari R, Jensen PH, Ramsey A, Goldstein DS, Miller GW, Salahpour A. Enhanced tyrosine hydroxylase activity induces oxidative stress, causes accumulation of autotoxic catecholamine metabolites, and augments amphetamine effects in vivo. J Neurochem 2021; 158:960-979. [PMID: 33991113 PMCID: PMC8376767 DOI: 10.1111/jnc.15432] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 05/10/2021] [Accepted: 05/10/2021] [Indexed: 12/12/2022]
Abstract
In Parkinson's disease, dopamine‐containing nigrostriatal neurons undergo profound degeneration. Tyrosine hydroxylase (TH) is the rate‐limiting enzyme in dopamine biosynthesis. TH increases in vitro formation of reactive oxygen species, and previous animal studies have reported links between cytosolic dopamine build‐up and oxidative stress. To examine effects of increased TH activity in catecholaminergic neurons in vivo, we generated TH‐over‐expressing mice (TH‐HI) using a BAC‐transgenic approach that results in over‐expression of TH with endogenous patterns of expression. The transgenic mice were characterized by western blot, qPCR, and immunohistochemistry. Tissue contents of dopamine, its metabolites, and markers of oxidative stress were evaluated. TH‐HI mice had a 3‐fold increase in total and phosphorylated TH levels and an increased rate of dopamine synthesis. Coincident with elevated dopamine turnover, TH‐HI mice showed increased striatal production of H2O2 and reduced glutathione levels. In addition, TH‐HI mice had elevated striatal levels of the neurotoxic dopamine metabolites 3,4‐dihydroxyphenylacetaldehyde and 5‐S‐cysteinyl‐dopamine and were more susceptible than wild‐type mice to the effects of amphetamine and methamphetamine. These results demonstrate that increased TH alone is sufficient to produce oxidative stress in vivo, build up autotoxic dopamine metabolites, and augment toxicity.
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Affiliation(s)
- Laura M Vecchio
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Patricia Sullivan
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological, Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Amy R Dunn
- The Jackson Laboratory. Bar Harbor, Maine, USA
| | - Marie Kristel Bermejo
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Rong Fu
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Shababa T Masoud
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Emil Gregersen
- Danish Research Institute of Translational Neuroscience - DANDRITE, Department of Biomedicine, Faculty of Health, Aarhus University, Aarhus C., Denmark
| | - Nikhil M Urs
- Department of Pharmacology and Therapeutics, University of Florida, Gainsville, FL, USA
| | - Reza Nazari
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Poul Henning Jensen
- Danish Research Institute of Translational Neuroscience - DANDRITE, Department of Biomedicine, Faculty of Health, Aarhus University, Aarhus C., Denmark
| | - Amy Ramsey
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - David S Goldstein
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological, Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Gary W Miller
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University Medical Centre, New York, NY, USA
| | - Ali Salahpour
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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19
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Bradner JM, Kalia V, Lau FK, Sharma M, Bucher ML, Johnson M, Chen M, Walker DI, Jones DP, Miller GW. Genetic or Toxicant-Induced Disruption of Vesicular Monoamine Storage and Global Metabolic Profiling in Caenorhabditis elegans. Toxicol Sci 2021; 180:313-324. [PMID: 33538833 PMCID: PMC8041460 DOI: 10.1093/toxsci/kfab011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The proper storage and release of monoamines contributes to a wide range of neuronal activity. Here, we examine the effects of altered vesicular monoamine transport in the nematode Caenorhabditis elegans. The gene cat-1 is responsible for the encoding of the vesicular monoamine transporter (VMAT) in C. elegans and is analogous to the mammalian vesicular monoamine transporter 2 (VMAT2). Our laboratory has previously shown that reduced VMAT2 activity confers vulnerability on catecholamine neurons in mice. The purpose of this article was to determine whether this function is conserved and to determine the impact of reduced VMAT activity in C. elegans. Here we show that deletion of cat-1/VMAT increases sensitivity to the neurotoxicant 1-methyl-4-phenylpyridinium (MPP+) as measured by enhanced degeneration of dopamine neurons. Reduced cat-1/VMAT also induces changes in dopamine-mediated behaviors. High-resolution mass spectrometry-based metabolomics in the whole organism reveals changes in amino acid metabolism, including tyrosine metabolism in the cat-1/VMAT mutants. Treatment with MPP+ disrupted tryptophan metabolism. Both conditions altered glycerophospholipid metabolism, suggesting a convergent pathway of neuronal dysfunction. Our results demonstrate the evolutionarily conserved nature of monoamine function in C. elegans and further suggest that high-resolution mass spectrometry-based metabolomics can be used in this model to study environmental and genetic contributors to complex human disease.
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Affiliation(s)
- Joshua M Bradner
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, USA
| | - Vrinda Kalia
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, USA
| | - Fion K Lau
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, USA
| | - Monica Sharma
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, USA
| | - Meghan L Bucher
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, USA
| | - Michelle Johnson
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia 30322, USA
| | - Merry Chen
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia 30322, USA
| | - Douglas I Walker
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Dean P Jones
- Department of Medicine, School of Medicine, Emory University, Atlanta, Georgia 30303, USA
| | - Gary W Miller
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, USA
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20
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Black CA, Bucher ML, Bradner JM, Jonas L, Igarza K, Miller GW. Assessing Vesicular Monoamine Transport and Toxicity Using Fluorescent False Neurotransmitters. Chem Res Toxicol 2020; 34:1256-1264. [PMID: 33378168 DOI: 10.1021/acs.chemrestox.0c00380] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Impairments in the vesicular packaging of dopamine result in an accumulation of dopamine in the cytosol. Cytosolic dopamine is vulnerable to two metabolic processes-enzymatic catabolism and enzymatic- or auto-oxidation-that form toxic metabolites and generate reactive oxygen species. Alterations in the expression or activity of the vesicular monoamine transporter 2 (VMAT2), which transports monoamines such as dopamine from the cytosol into the synaptic vesicle, result in dysregulated dopamine packaging. Here, we developed a series of assays using the fluorescent false neurotransmitter 206 (FFN206) to visualize VMAT2-mediated vesicular packaging at baseline and following pharmacological and toxicological manipulations. As a proof of principle, we observed a significant reduction in vesicular FFN206 packaging after treatment with the VMAT2 inhibitors reserpine (IC50: 73.1 nM), tetrabenazine (IC50: 30.4 nM), methamphetamine (IC50: 2.4 μM), and methylphenidate (IC50: 94.3 μM). We then applied the assay to investigate the consequences on vesicular packaging by environmental toxicants including the pesticides paraquat, rotenone, and chlorpyrifos, as well as the halogenated compounds unichlor, perfluorooctanesulfonic acid, Paroil, Aroclor 1260, and hexabromocyclododecane. Several of the environmental toxicants showed minor impairment of the vesicular FFN206 loading, suggesting that the toxicants are weak VMAT2 inhibitors at the concentrations tested. The assay presented here can be applied to investigate the effect of additional pharmacological compounds and environmental toxicants on vesicular function, which will provide insight into how exposures to such factors are involved in the pathogenesis of monoaminergic diseases such as Parkinson's disease, and the assay can be used to identify pharmacological agents that influence VMAT2 activity.
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Affiliation(s)
- Carlie A Black
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia 30322, United States
| | - Meghan L Bucher
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, United States
| | - Joshua M Bradner
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, United States
| | - Lauren Jonas
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia 30322, United States
| | - Kenny Igarza
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia 30322, United States
| | - Gary W Miller
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, United States
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21
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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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22
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Sakano D, Uefune F, Tokuma H, Sonoda Y, Matsuura K, Takeda N, Nakagata N, Kume K, Shiraki N, Kume S. VMAT2 Safeguards β-Cells Against Dopamine Cytotoxicity Under High-Fat Diet-Induced Stress. Diabetes 2020; 69:2377-2391. [PMID: 32826296 PMCID: PMC7576560 DOI: 10.2337/db20-0207] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 08/17/2020] [Indexed: 12/13/2022]
Abstract
Vesicular monoamine transporter 2 (VMAT2) uptakes cytoplasmic monoamines into vesicles for storage. VMAT2 plays a role in modulating insulin release by regulating dopamine levels in the pancreas, although the exact mechanism remains elusive. We found that VMAT2 expression in β-cells specifically increases under high blood glucose conditions. The islets isolated from β-cell-specific Vmat2 knockout (βVmat2KO) mice show elevated insulin secretion levels in response to glucose stimulation. Under prolonged high-fat diet feedings, the βVmat2KO mice exhibit impaired glucose and insulin tolerance and progressive β-cell dysfunction. Here we demonstrate VMAT2 uptake of dopamine to protect dopamine from degradation by monoamine oxidase, thereby safeguarding β-cells from excess reactive oxygen species (ROS) exposure. In the context of high demand for insulin secretion, the absence of VMAT2 leads to elevated ROS in β-cells, which accelerates β-cell dedifferentiation and β-cell loss. Therefore, VMAT2 controls the amount of dopamine in β-cells, thereby protecting pancreatic β-cells from excessive oxidative stress.
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Affiliation(s)
- Daisuke Sakano
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
| | - Fumiya Uefune
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
| | - Hiraku Tokuma
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
| | - Yuki Sonoda
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
| | - Kumi Matsuura
- Department of Stem Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan
| | - Naoki Takeda
- Division of Developmental Genetics, Institute of Resource Development and Analysis, Kumamoto University, Kumamoto, Japan
| | - Naomi Nakagata
- Division of Reproductive Engineering, Center for Animal Resources and Development, Kumamoto University, Kumamoto, Japan
| | - Kazuhiko Kume
- Department of Neuropharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Nobuaki Shiraki
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
| | - Shoen Kume
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
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23
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Goldstein DS. The "Sick-but-not-Dead" Phenomenon Applied to Catecholamine Deficiency in Neurodegenerative Diseases. Semin Neurol 2020; 40:502-514. [PMID: 32906170 PMCID: PMC10680399 DOI: 10.1055/s-0040-1713874] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The catecholamines dopamine and norepinephrine are key central neurotransmitters that participate in many neurobehavioral processes and disease states. Norepinephrine is also the main neurotransmitter mediating regulation of the circulation by the sympathetic nervous system. Several neurodegenerative disorders feature catecholamine deficiency. The most common is Parkinson's disease (PD), in which putamen dopamine content is drastically reduced. PD also entails severely decreased myocardial norepinephrine content, a feature that characterizes two other Lewy body diseases-pure autonomic failure and dementia with Lewy bodies. It is widely presumed that tissue catecholamine depletion in these conditions results directly from loss of catecholaminergic neurons; however, as highlighted in this review, there are also important functional abnormalities in extant residual catecholaminergic neurons. We refer to this as the "sick-but-not-dead" phenomenon. The malfunctions include diminished dopamine biosynthesis via tyrosine hydroxylase (TH) and L-aromatic-amino-acid decarboxylase (LAAAD), inefficient vesicular sequestration of cytoplasmic catecholamines, and attenuated neuronal reuptake via cell membrane catecholamine transporters. A unifying explanation for catecholaminergic neurodegeneration is autotoxicity exerted by 3,4-dihydroxyphenylacetaldehyde (DOPAL), an obligate intermediate in cytoplasmic dopamine metabolism. In PD, putamen DOPAL is built up with respect to dopamine, associated with a vesicular storage defect and decreased aldehyde dehydrogenase activity. Probably via spontaneous oxidation, DOPAL potently oligomerizes and forms quinone-protein adducts with ("quinonizes") α-synuclein (AS), a major constituent in Lewy bodies, and DOPAL-induced AS oligomers impede vesicular storage. DOPAL also quinonizes numerous intracellular proteins and inhibits enzymatic activities of TH and LAAAD. Treatments targeting DOPAL formation and oxidation therefore might rescue sick-but-not-dead catecholaminergic neurons in Lewy body diseases.
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Affiliation(s)
- David S. Goldstein
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
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24
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Nolan SO, Zachry JE, Johnson AR, Brady LJ, Siciliano CA, Calipari ES. Direct dopamine terminal regulation by local striatal microcircuitry. J Neurochem 2020; 155:475-493. [PMID: 32356315 DOI: 10.1111/jnc.15034] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 04/20/2020] [Accepted: 04/22/2020] [Indexed: 02/06/2023]
Abstract
Regulation of axonal dopamine release by local microcircuitry is at the hub of several biological processes that govern the timing and magnitude of signaling events in reward-related brain regions. An important characteristic of dopamine release from axon terminals in the striatum is that it is rapidly modulated by local regulatory mechanisms. These processes can occur via homosynaptic mechanisms-such as presynaptic dopamine autoreceptors and dopamine transporters - as well heterosynaptic mechanisms such as retrograde signaling from postsynaptic cholinergic and dynorphin systems, among others. Additionally, modulation of dopamine release via diffusible messengers, such as nitric oxide and hydrogen peroxide, allows for various metabolic factors to quickly and efficiently regulate dopamine release and subsequent signaling. Here we review how these mechanisms work in concert to influence the timing and magnitude of striatal dopamine signaling, independent of action potential activity at the level of dopaminergic cell bodies in the midbrain, thereby providing a parallel pathway by which dopamine can be modulated. Understanding the complexities of local regulation of dopamine signaling is required for building comprehensive frameworks of how activity throughout the dopamine system is integrated to drive signaling and control behavior.
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Affiliation(s)
- Suzanne O Nolan
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Jennifer E Zachry
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Amy R Johnson
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Lillian J Brady
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Cody A Siciliano
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN TN, USA
| | - Erin S Calipari
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN TN, USA.,Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA.,Department of Psychiatry and Behavioral Sciences, Vanderbilt University, Nashville, TN, USA
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25
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Branco RC, Burkett JP, Black CA, Winokur E, Elsworth W, Dhamsania RK, Lohr KM, Schroeder JP, Weinshenker D, Jovanovic T, Miller GW. Vesicular monoamine transporter 2 mediates fear behavior in mice. GENES, BRAIN, AND BEHAVIOR 2020; 19:e12634. [PMID: 31898856 PMCID: PMC8170828 DOI: 10.1111/gbb.12634] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 12/27/2019] [Accepted: 12/29/2019] [Indexed: 11/26/2022]
Abstract
A subset of people exposed to a traumatic event develops post-traumatic stress disorder (PTSD), which is associated with dysregulated fear behavior. Genetic variation in SLC18A2, the gene that encodes vesicular monoamine transporter 2 (VMAT2), has been reported to affect risk for the development of PTSD in humans. Here, we use transgenic mice that express either 5% (VMAT2-LO mice) or 200% (VMAT2-HI mice) of wild-type levels of VMAT2 protein. We report that VMAT2-LO mice have reduced VMAT2 protein in the hippocampus and amygdala, impaired monoaminergic vesicular storage capacity in both the striatum and frontal cortex, decreased monoamine metabolite abundance and a greatly reduced capacity to release dopamine upon stimulation. Furthermore, VMAT2-LO mice showed exaggerated cued and contextual fear expression, altered fear habituation, inability to discriminate threat from safety cues, altered startle response compared with wild-type mice and an anxiogenic-like phenotype, but displayed no deficits in social function. By contrast, VMAT2-HI mice exhibited increased VMAT2 protein throughout the brain, higher vesicular storage capacity and greater dopamine release upon stimulation compared with wild-type controls. Behaviorally, VMAT2-HI mice were similar to wild-type mice in most assays, with some evidence of a reduced anxiety-like responses. Together, these data show that presynaptic monoamine function mediates PTSD-like outcomes in our mouse model, and suggest a causal link between reduced VMAT2 expression and fear behavior, consistent with the correlational relationship between VMAT2 genotype and PTSD risk in humans. Targeting this system is a potential strategy for the development of pharmacotherapies for disorders like PTSD.
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Affiliation(s)
- Rachel C. Branco
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - James P. Burkett
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Carlie A. Black
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Emily Winokur
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - William Elsworth
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Rohan K. Dhamsania
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Kelly M. Lohr
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Jason P. Schroeder
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia
| | - David Weinshenker
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia
| | - Tanja Jovanovic
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, Georgia
| | - Gary W. Miller
- Department of Environmental Health, Rollins School of Public Health, Department of Pharmacology, Department of Neurology, Center for Neurodegenerative Diseases, Emory University, Atlanta, Georgia
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26
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Chen Q, Qu K, Ma Z, Zhan J, Zhang F, Shen J, Ning Q, Jia P, Zhang J, Chen N, Chen H, Huang B, Lei C. Genome-Wide Association Study Identifies Genomic Loci Associated With Neurotransmitter Concentration in Cattle. Front Genet 2020; 11:139. [PMID: 32292413 PMCID: PMC7119242 DOI: 10.3389/fgene.2020.00139] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 02/06/2020] [Indexed: 11/30/2022] Open
Abstract
Abnormal neurotransmitter concentration is one of the factors that affect the health status, behavioral personality, and welfare level of animals, but the genetic basis of the abnormality is still largely unknown. The objective of this study is to identify putative genomic loci associated with neurotransmitter concentration in cattle. We measured serotonin (5HT), dopamine (DA), cortisol, glutamate (Glu), and ACTH concentrations in blood serum using double-antibody sandwich ELISA in 30 Brahman cattle and 127 Yunling cattle. Interestingly, we found that ACTH concentration was positively correlated with body weight, cannon circumference, and hip width (P < 0.05). Genome-wide association study (GWAS) was performed with mixed linear models using autosomal SNPs derived from the whole-genome sequence. We identified five, five, two, three, and five suggestive loci associated with 5HT, DA, cortisol, Glu, and ACTH concentration, respectively. These 20 associated loci implicated 18 candidate genes. For Glu concentration, the most significant association locus was assigned to MCHR1, a G-coupled receptor that could modulate glutamate release. For dopamine concentration, a very strong association locus was located in the intron of SLC18A2, which is a critical mediator of dopamine dynamics. However, for ACTH concentration, a very strong association locus was assigned to HTR1F, a G protein-coupled receptor that can influence the release of ACTH. Other candidate genes of interest identified for neurotransmitter concentration were PRMT6, GADD45A, PCCA, ANGPT1, ACCS, LOC100336971, TNR, GSDMA, CNTN3, CARMIL1, CDKAL1, RBFOX1, PCDH15, and LGALS12. Our findings will provide targets for the genetic improvement of neurotransmitter-related traits in domestic cattle and basic materials for studying the mechanism of neurotransmitter synthesis, release, and transport in human and animals.
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Affiliation(s)
- Qiuming Chen
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Kaixing Qu
- Yunnan Academy of Grassland and Animal Science, Kunming, China
| | - Zhijie Ma
- Academy of Animal Science and Veterinary Medicine, Qinghai University, Xining, China
| | - Jingxi Zhan
- Yunnan Academy of Grassland and Animal Science, Kunming, China
| | - Fengwei Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Jiafei Shen
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Qingqing Ning
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Peng Jia
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Jicai Zhang
- Yunnan Academy of Grassland and Animal Science, Kunming, China
| | - Ningbo Chen
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Hong Chen
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Bizhi Huang
- Yunnan Academy of Grassland and Animal Science, Kunming, China
| | - Chuzhao Lei
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
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27
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Effects of NBI-98782, a selective vesicular monoamine transporter 2 (VMAT2) inhibitor, on neurotransmitter efflux and phencyclidine-induced locomotor activity: Relevance to tardive dyskinesia and antipsychotic action. Pharmacol Biochem Behav 2020; 190:172872. [PMID: 32084491 DOI: 10.1016/j.pbb.2020.172872] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 01/24/2020] [Accepted: 02/15/2020] [Indexed: 01/31/2023]
Abstract
Valbenazine, a vesicular monoamine transporter 2 (VMAT2, SLC18A2) inhibitor, is a newly approved treatment for tardive dyskinesia. VMAT2 is present in the membrane of secretory vesicles and transports dopamine (DA), norepinephrine (NE), serotonin (5-HT), histamine, glutamate (Glu), and GABA into vesicles for presynaptic release. We utilized microdialysis in awake, freely moving mice to determine the effect of NBI-98782, the active metabolite of valbenazine, alone, or in combination with several antipsychotic drugs (APDs), to influence neurotransmitter efflux in the medial prefrontal cortex (mPFC), dorsal striatum (dSTR), hippocampus and nucleus accumbens (NAC); we also compared it with tetrabenazine, the prototypical VMAT2 inhibitor. Acute NBI-98782 and tetrabenazine decreased mPFC, dSTR, hippocampus, and NAC DA, 5-HT, and NE efflux, while increasing that of DOPAC, HVA, and 5-HIAA. Sub-chronic NBI-98782 (7 days) decreased baseline DA and 5-HT efflux in both mPFC and dSTR. NBI-98782 elicited similar effects on neurotransmitter efflux in sub-chronic NBI-98782-treated mice but also enhanced ACh and GABA; the decrease in DA efflux in mPFC and dSTR was not significant in the sc-treated animals. NBI-98782 suppressed clozapine-, olanzapine- and risperidone-induced DA efflux in both mPFC and dSTR, and ACh efflux in mPFC. NBI-98782 suppressed the haloperidol-induced DA efflux in dSTR, with minimal effect on GABA efflux. NBI-98782 attenuated PCP-induced DA, 5-HT, NE and Glu efflux, and AMPH-induced DA and NE efflux, in both mPFC and dSTR, as well as PCP- and AMPH-induced hyperlocomotion, suggesting possible beneficial antipsychotic effects.
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28
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Increased endogenous dopamine prevents myopia in mice. Exp Eye Res 2020; 193:107956. [PMID: 32032629 DOI: 10.1016/j.exer.2020.107956] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 01/31/2020] [Accepted: 02/01/2020] [Indexed: 02/01/2023]
Abstract
Experimental evidence suggests that dopamine (DA) modulates refractive eye growth. We evaluated whether increasing endogenous DA activity using pharmacological or genetic approaches decreased myopia susceptibility in mice. First, we assessed the effects of systemic L-3,4-dihydroxyphenylalanine (L-DOPA) injections on form deprivation myopia (FDM) in C57BL/6 J (WTC57) mice. WTC57 mice received daily systemic injections of L-DOPA (n = 11), L-DOPA + ascorbic acid (AA, n = 22), AA (n = 20), or Saline (n = 16). Second, we tested transgenic mice with increased or decreased expression of vesicular monoamine transporter 2 (VMAT2HI, n = 22; WTHI, n = 18; VMAT2LO, n = 18; or WTLO, n = 9) under normal and form deprivation conditions. VMAT2 packages DA into vesicles, affecting DA release. At post-natal day 28 (P28), monocular FD was induced in each genotype. Weekly measurements of refractive error, corneal curvature, and ocular biometry were performed until P42 or P49. WTC57 mice exposed to FD developed a significant myopic shift (treated-contralateral eye) in AA (-3.27 ± 0.73D) or saline (-3.71 ± 0.80D) treated groups that was significantly attenuated by L-DOPA (-0.73 ± 0.90D, p = 0.0002) or L-DOPA + AA (-0.11 ± 0.46D, p = 0.0103). The VMAT2LO mice, with under-expression of VMAT2, were most susceptible to FDM. VMAT2LO mice developed significant myopic shifts to FD after one week compared to VMAT2HI and WT mice (VMAT2LO: -5.48 ± 0.54D; VMAT2HI: -0.52 ± 0.92D, p < 0.05; WT: -2.13 ± 0.78D, p < 0.05; ungoggled control: -0.22 ± 0.24D, p < 0.001). These results indicate that endogenously increasing DA synthesis and release by genetic and pharmacological methods prevents FDM in mice.
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29
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Rai SN, Singh P. Advancement in the modelling and therapeutics of Parkinson's disease. J Chem Neuroanat 2020; 104:101752. [PMID: 31996329 DOI: 10.1016/j.jchemneu.2020.101752] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Revised: 01/19/2020] [Accepted: 01/20/2020] [Indexed: 02/08/2023]
Abstract
Since the discovery of L-dopa in the middle of the 20th century (1960s), there is not any neuroprotective therapy available although significant development has been made in the treatment of symptomatic Parkinson's disease (PD). Neurological disorders like PD can be modelled in animals so as to recapitulates most of the symptoms seen in PD patients. In aging population, PD is the second most common neurodegenerative disease after Alzheimer's disease, even though significant outcomes have been achieved in PD research yet it still is a mystery to solve the treatments for PD. In the last two decades, PD models have provided enhanced precision into the understanding of the process of PD disease, its etiology, pathology, and molecular mechanisms behind it. Furthermore, at the same time as cellular models have helped to recognize specific events, animal models, both toxic and genetic, have replicated almost all of the hallmarks of PD and are very helpful for testing and finding new strategies for neuroprotection. Recently, in both classical and newer models, major advances have been done in the modelling of supplementary PD features have come into the light. In this review, we have try to provide an updated summary of the characteristics of these models related to in vitro and in vivo models, animal models for PD, stem cell model for PD, newer 3D model as well as the strengths and limitations of these most popular PD models.
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Affiliation(s)
- Sachchida Nand Rai
- Department of Zoology, Mahila Maha Vidhyalaya, Institute of Science, Banaras Hindu University, Varanasi, India.
| | - Payal Singh
- Department of Zoology, Mahila Maha Vidhyalaya, Institute of Science, Banaras Hindu University, Varanasi, India.
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30
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How Important Is the Use of Cocaine and Amphetamines in the Development of Parkinson Disease? A Computational Study. Neurotox Res 2019; 37:724-731. [DOI: 10.1007/s12640-019-00149-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/18/2019] [Accepted: 11/29/2019] [Indexed: 11/25/2022]
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31
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Cholanians AB, Phan AV, Lau SS, Monks TJ. Concurrent Inhibition of Vesicular Monoamine Transporter 2 Does Not Protect Against 3,4-Methylenedioxymethamphetamine (Ecstasy) Induced Neurotoxicity. Toxicol Sci 2019; 170:157-166. [PMID: 30923810 DOI: 10.1093/toxsci/kfz085] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
3, 4-Methylenedioxymethamphetamine (MDMA) is a hallucinogenic amphetamine derivative. The acute effects of MDMA are hyperthermia, hyperactivity, and behavioral changes, followed by long-term serotonergic neurotoxicity in rats and primates. However, the underlying mechanisms of MDMA neurotoxicity remain elusive. We reported that pretreatment of rats with Ro 4-1284, a reversible inhibitor of the vesicular monoamine transporter 2 (VMAT2), reduced MDMA-induced hyperactivity in rats, abolished the hyperthermic response, and the long-term neurotoxicity. Current studies focused on the effects of co- and/or postinhibition of VMAT2 on the acute and chronic effects of MDMA and on the dose-response relationship between MDMA-induced elevations in body temperature and subsequent reductions in indolamine concentrations. Sprague Dawley rats were treated with MDMA (20, 25, or 27.5 mg/kg sc), and either co- and/or posttreatment with the VMAT2 inhibitor (10 mg/kg ip). Rats simultaneously treated with Ro 4-1284 and MDMA exhibited a more rapid increase in body temperature compared to just MDMA. However, the duration of the elevated body temperature was significantly shortened (approximately 3 h vs approximately 8 h, respectively). A similar body temperature response was observed in rats posttreated (7 h after MDMA) with Ro 4-1284. Despite decreases in the area under the curve (Δtemp X time) of body temperature caused by Ro 4-1284, there were no significant differences in the degree of indolamine depletion between any of the MDMA-treated groups. The results suggest that the neuroprotective effects of VMAT2 inhibition is likely due to the indirect monoamine depleting effects of the Ro 4-1284 pretreatment, rather than by the direct inhibition of VMAT2 function.
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Affiliation(s)
- Aram B Cholanians
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona 85721
| | - Andy V Phan
- Department of Radiation Oncology, School of Medicine, University of Colorado Denver, Denver, Colorado 80045
| | - Serrine S Lau
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan 48201
| | - Terrence J Monks
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan 48201
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32
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Valian N, Heravi M, Ahmadiani A, Dargahi L. Effect of methamphetamine on rat primary midbrain cells; mitochondrial biogenesis as a compensatory response. Neuroscience 2019; 406:278-289. [DOI: 10.1016/j.neuroscience.2019.03.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 02/25/2019] [Accepted: 03/07/2019] [Indexed: 01/07/2023]
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33
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Mor DE, Daniels MJ, Ischiropoulos H. The usual suspects, dopamine and alpha-synuclein, conspire to cause neurodegeneration. Mov Disord 2019; 34:167-179. [PMID: 30633814 DOI: 10.1002/mds.27607] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 11/15/2018] [Accepted: 12/03/2018] [Indexed: 01/07/2023] Open
Abstract
Parkinson's disease (PD) is primarily a movement disorder driven by the loss of dopamine-producing neurons in the substantia nigra (SN). Early identification of the oxidative properties of dopamine implicated it as a potential source of oxidative stress in PD, yet few studies have investigated dopamine neurotoxicity in vivo. The discovery of PD-causing mutations in α-synuclein and the presence of aggregated α-synuclein in the hallmark Lewy body pathology of PD revealed another important player. Despite extensive efforts, the precise role of α-synuclein aggregation in neurodegeneration remains unclear. We recently manipulated both dopamine levels and α-synuclein expression in aged mice and found that only the combination of these 2 factors caused progressive neurodegeneration of the SN and an associated motor deficit. Dopamine modified α-synuclein aggregation in the SN, resulting in greater abundance of α-synuclein oligomers and unique dopamine-induced oligomeric conformations. Furthermore, disruption of the dopamine-α-synuclein interaction rescued dopaminergic neurons from degeneration in transgenic Caenorhabditis elegans models. In this Perspective, we discuss these findings in the context of known α-synuclein and dopamine biology, review the evidence for α-synuclein oligomer toxicity and potential mechanisms, and discuss therapeutic implications. © 2019 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Danielle E Mor
- Lewis-Sigler Institute for Integrative Genomics and Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Malcolm J Daniels
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Harry Ischiropoulos
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania, USA
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34
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Luikinga SJ, Kim JH, Perry CJ. Developmental perspectives on methamphetamine abuse: Exploring adolescent vulnerabilities on brain and behavior. Prog Neuropsychopharmacol Biol Psychiatry 2018; 87:78-84. [PMID: 29128447 DOI: 10.1016/j.pnpbp.2017.11.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 11/06/2017] [Accepted: 11/08/2017] [Indexed: 01/25/2023]
Abstract
Most people that experience illicit drugs do so for the first time during adolescence, and methamphetamine (meth) is no exception. Therefore, research into the effects of meth should highlight the adolescent period. Despite this, the vast majority of current literature has mainly focused on meth exposure during adulthood. In this review, we first describe existing literature that compares the behavioral effects of meth where exposure occurs in adolescence compared to adulthood. Given that there are actually very few such studies, we also look at what is known about neural effects of meth in the adult brain, and relate these to normal neural development occurring during the adolescent period to establish how meth may target maturing regions and related neurochemistry. What emerges overall is that adolescents appear to be more vulnerable to the rewarding and reinforcing effects of meth, and that meth indeed has effects on areas that are in flux during adolescence. However, there is some evidence for a paradoxical resistance to the neurotoxic effects during this period. We highlight the need for further age-related research to better understand, treat, and prevent meth use disorders and addiction in general.
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Affiliation(s)
- Sophia J Luikinga
- Behavioral Neuroscience Division, The Florey Institute of Neuroscience and Mental Health, VIC, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, VIC, Australia.
| | - Jee Hyun Kim
- Behavioral Neuroscience Division, The Florey Institute of Neuroscience and Mental Health, VIC, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, VIC, Australia
| | - Christina J Perry
- Behavioral Neuroscience Division, The Florey Institute of Neuroscience and Mental Health, VIC, Australia; Florey Department of Neuroscience and Mental Health, University of Melbourne, VIC, Australia.
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Mulvihill KG. Presynaptic regulation of dopamine release: Role of the DAT and VMAT2 transporters. Neurochem Int 2018; 122:94-105. [PMID: 30465801 DOI: 10.1016/j.neuint.2018.11.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 10/28/2018] [Accepted: 11/08/2018] [Indexed: 01/23/2023]
Abstract
The signaling dynamics of the neurotransmitter dopamine has been established to have an important role in a variety of behavioural processes including motor control, cognition, and emotional processing. Key regulators of transmitter release and the signaling dynamics of dopamine are the plasma membrane reuptake transporter (DAT) and the vesicular monoamine transporter (VMAT2). These proteins serve to remove dopamine molecules from the extracellular and cytosolic space, respectively and both determine the amount of transmitter released from synaptic vesicles. This review provides an overview of how these transporter proteins are involved in molecular regulation and function together to govern the dynamics of vesicular release with opposing effects on the quantal size and extracellular concentration of dopamine. These transporter proteins are both focal points of convergence for a variety of regulatory molecular cascades as well as targets for many pharmacological agents. The ratio between these transporters is argued to be useful as a molecular marker for delineating dopamine functional subsystems that may differ in transmitter release patterns.
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Affiliation(s)
- Kevin G Mulvihill
- Department of Psychology, Brock University, St. Catharines, ON, L2S 3A1, Canada.
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Abstract
Aminorex (5-phenyl-4,5-dihydro-1,3-oxazol-2-amine) and 4-methylaminorex (4-methyl-5-phenyl-4,5-dihydro-1,3-oxazol-2-amine) are psychostimulants that have long been listed in Schedules IV and I of the UN Convention on Psychotropic Substances of 1971. However, a range of psychoactive analogues exist that are not internationally controlled and therefore often classified as new psychoactive substances (NPS). Aminorex analogues encompass failed pharmaceuticals that reemerged as drugs of abuse, and newly synthesized substances that were solely designed for recreational use by clandestine chemists. NPS, sometimes also referred to as "designer drugs" in alignment with a phenomenon arising in the early 1980s, serve as alternatives to controlled drugs. Aminorex and its derivatives interact with monoaminergic neurotransmission by interfering with the function of monoamine transporters. Hence, these compounds share pharmacological and neurochemical similarities with amphetamines and cocaine. The consumption of aminorex, 4-methylaminorex and 4,4'-dimethylaminorex (4-methyl-5-(4-methylphenyl)-4,5-dihydro-1,3-oxazol-2-amine) has been associated with adverse events including death, bestowing an inglorious fame on aminorex-derived drugs. In this Review, a historical background is presented, as well as an account of the pharmacodynamic and pharmacokinetic properties of aminorex and various analogues. Light is shed on their misuse as drug adulterants of well-established drugs on the market. This Review not only provides a detailed overview of an abused substance-class, but also emphasizes the darkest aspect of the NPS market, i.e., deleterious side effects that arise from the ingestion of certain NPS, as knowledge of the pharmacology, the potency, or the identity of the active ingredients remains obscure to NPS users.
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Affiliation(s)
- Julian Maier
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria
| | - Felix P. Mayer
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria
| | - Simon D. Brandt
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Harald H. Sitte
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria
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Cataldi S, Follett J, Fox JD, Tatarnikov I, Kadgien C, Gustavsson EK, Khinda J, Milnerwood AJ, Farrer MJ. Altered dopamine release and monoamine transporters in Vps35 p.D620N knock-in mice. NPJ PARKINSONS DISEASE 2018; 4:27. [PMID: 30155515 PMCID: PMC6104078 DOI: 10.1038/s41531-018-0063-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Revised: 07/05/2018] [Accepted: 07/09/2018] [Indexed: 11/09/2022]
Abstract
Vacuolar protein sorting 35 (VPS35) is a core component of the retromer trimer required for endosomal membrane-associated protein trafficking. The discovery of a missense mutation, Vps35 p.D620N implicates retromer dysfunction in the pathogenesis of Parkinson's disease (PD). We have characterized a knock-in mouse with a Vps35 p.D620N substitution (hereafter referred to as VKI) at 3 months of age. Standardized behavioral testing did not observe overt movement disorder. Tyrosine hydroxylase (TH)-positive nigral neuron counts and terminal expression in striata were comparable across genotypes. Fast scan cyclic voltammetry revealed increased dopamine release in VKI striatal slices. While extracellular dopamine collected via striatal microdialysis of freely moving animals was comparable across genotypes, the ratio of dopamine metabolites to dopamine suggests increased dopamine turnover in VKI homozygous mice. Western blot of striatal proteins revealed a genotype-dependent decrease in dopamine transporter (DAT) along with an increase in vesicular monoamine transporter 2 (VMAT2), albeit independent of changes in other synaptic markers. The reduction in DAT was further supported by immunohistochemical analysis. The data show that the dopaminergic system of VKI mice is profoundly altered relative to wild-type littermates. We conclude early synaptic dysfunction contributes to age-related pathophysiology in the nigrostriatal system that may lead to parkinsonism in man.
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Affiliation(s)
- Stefano Cataldi
- 1Centre for Applied Neurogenetics, University of British Columbia, Vancouver, Canada
| | - Jordan Follett
- 1Centre for Applied Neurogenetics, University of British Columbia, Vancouver, Canada
| | - Jesse D Fox
- 1Centre for Applied Neurogenetics, University of British Columbia, Vancouver, Canada
| | - Igor Tatarnikov
- 1Centre for Applied Neurogenetics, University of British Columbia, Vancouver, Canada
| | - Chelsie Kadgien
- 1Centre for Applied Neurogenetics, University of British Columbia, Vancouver, Canada
| | - Emil K Gustavsson
- 1Centre for Applied Neurogenetics, University of British Columbia, Vancouver, Canada.,2Department of Neurology, St. Olav's Hospital, Trondheim, Norway
| | - Jaskaran Khinda
- 1Centre for Applied Neurogenetics, University of British Columbia, Vancouver, Canada
| | - Austen J Milnerwood
- 1Centre for Applied Neurogenetics, University of British Columbia, Vancouver, Canada
| | - Matthew J Farrer
- 1Centre for Applied Neurogenetics, University of British Columbia, Vancouver, Canada
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Valian N, Ahmadiani A, Dargahi L. Increasing methamphetamine doses inhibit glycogen synthase kinase 3β activity by stimulating the insulin signaling pathway in substantia nigra. J Cell Biochem 2018; 119:8522-8530. [PMID: 30011098 DOI: 10.1002/jcb.27082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 04/26/2018] [Indexed: 01/01/2023]
Abstract
Methamphetamine (MA), a highly abused psychostimulant, exerts neurotoxic effects on the dopaminergic system via several neurotoxicity mechanisms in the long-term administration. Since the effect of MA on the signaling insulin pathway is less studied, the current study was designed to evaluate the effect of escalating an MA regimen on different insulin signaling elements in substantia nigra (SN) and striatum of a rat. Increasing MA doses (1-14 mg/kg) were administrated intraperitoneally twice a day for 14 days in rats. In the control group, normal saline was injected in the same volume. On days 1, 14, 28, and 60 after MA discontinuation, molecular assessments were performed. Insulin receptor (IR) and insulin receptor substrate (IRS) 1 and 2 gene expression were evaluated using real-time polymerase chain reaction, and protein levels of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K), phospho-PI3K, Akt, phospho-Akt, glycogen synthase kinase 3β (GSK3β), and phospho-GSK3β were measured by the Western blot analysis in SN and striatum. Messenger RNA levels of IR and insulin receptor substrate 2 were increased in SN, 1 day after the last injection. Although no changes were observed in PI3K, phospho-PI3K, Akt, phospho-Akt, and GSK3β levels, increase in the level of inactive form of GSK3β (phosphorylated on serine 9) was indicated in SN on day 28. In striatum, decreases in IR and phospho-Akt were demonstrated, without any change in other elements. Repeated escalating regimen of MA activated the insulin signaling pathway and inhibited GSK3β activity in SN. This response, which did not occur in striatum, may act as an adaptive mechanism to prevent MA-induced neurotoxicity in dopaminergic cell bodies.
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Affiliation(s)
- Neda Valian
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abolhassan Ahmadiani
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Leila Dargahi
- Neurobiology Research Center, Shahid Beheshti University ofMedical Sciences, Tehran, Iran
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Maier J, Mayer FP, Luethi D, Holy M, Jäntsch K, Reither H, Hirtler L, Hoener MC, Liechti ME, Pifl C, Brandt SD, Sitte HH. The psychostimulant (±)-cis-4,4'-dimethylaminorex (4,4'-DMAR) interacts with human plasmalemmal and vesicular monoamine transporters. Neuropharmacology 2018; 138:282-291. [PMID: 29908239 DOI: 10.1016/j.neuropharm.2018.06.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/01/2018] [Accepted: 06/12/2018] [Indexed: 10/28/2022]
Abstract
(±)-cis-4,4'-Dimethylaminorex (4,4'-DMAR) is a new psychoactive substance (NPS) that has been associated with 31 fatalities and other adverse events in Europe between June 2013 and February 2014. We used in vitro uptake inhibition and transporter release assays to determine the effects of 4,4'-DMAR on human high-affinity transporters for dopamine (DAT), norepinephrine (NET) and serotonin (SERT). In addition, we assessed its binding affinities to monoamine receptors and transporters. Furthermore, we investigated the interaction of 4,4'-DMAR with the vesicular monoamine transporter 2 (VMAT2) in rat phaeochromocytoma (PC12) cells and synaptic vesicles prepared from human striatum. 4,4'-DMAR inhibited uptake mediated by human DAT, NET or SERT, respectively in the low micromolar range (IC50 values < 2 μM). Release assays identified 4,4'-DMAR as a substrate type releaser, capable of inducing transporter-mediated reverse transport via DAT, NET and SERT. Furthermore, 4,4'-DMAR inhibited both the rat and human isoforms of VMAT2 at a potency similar to 3,4-methylenedioxymethylamphetamine (MDMA). This study identified 4,4'-DMAR as a potent non-selective monoamine releasing agent. In contrast to the known effects of aminorex and 4-methylaminorex, 4,4'-DMAR exerts profound effects on human SERT. The latter finding is consistent with the idea that fatalities associated with its abuse may be linked to monoaminergic toxicity including serotonin syndrome. The activity at VMAT2 suggests that chronic abuse of 4,4'-DMAR may result in long-term neurotoxicity.
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Affiliation(s)
- Julian Maier
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria
| | - Felix P Mayer
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria
| | - Dino Luethi
- University Hospital Basel and University of Basel, Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, Hebelstraße 20, 4031, Basel, Switzerland
| | - Marion Holy
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria
| | - Kathrin Jäntsch
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria
| | - Harald Reither
- Medical University of Vienna, Center for Brain Research, Department of Molecular Neurosciences, Spitalgasse 4, 1090, Vienna, Austria
| | - Lena Hirtler
- Medical University of Vienna, Center for Anatomy and Cell Biology, Währingerstraße 13, 1090, Vienna, Austria
| | - Marius C Hoener
- F. Hoffmann - La Roche Ltd., pRED, Roche Innovation Center Basel, Neuroscience Research, Department of Neurosymptomatic Domains, Grenzacherstraße 124, 4070, Basel, Switzerland
| | - Matthias E Liechti
- University Hospital Basel and University of Basel, Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, Hebelstraße 20, 4031, Basel, Switzerland
| | - Christian Pifl
- Medical University of Vienna, Center for Brain Research, Department of Molecular Neurosciences, Spitalgasse 4, 1090, Vienna, Austria
| | - Simon D Brandt
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Harald H Sitte
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria; Center for Addiction Research and Science, Medical University Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria.
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Hedges DM, Obray JD, Yorgason JT, Jang EY, Weerasekara VK, Uys JD, Bellinger FP, Steffensen SC. Methamphetamine Induces Dopamine Release in the Nucleus Accumbens Through a Sigma Receptor-Mediated Pathway. Neuropsychopharmacology 2018; 43:1405-1414. [PMID: 29185481 PMCID: PMC5916361 DOI: 10.1038/npp.2017.291] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 11/14/2017] [Accepted: 11/16/2017] [Indexed: 12/16/2022]
Abstract
Methamphetamine (METH) is a drug with a high addictive potential that is widely abused across the world. Although it is known that METH dysregulates both dopamine transmission and dopamine reuptake, the specific mechanism of action remains obscure. One promising target of METH is the sigma receptor, a chaperone protein located on the membrane of the endoplasmic reticulum. Using fast-scan cyclic voltammetry, we show that METH-enhancement of evoked dopamine release and basal efflux is dependent on sigma receptor activation. METH-induced activation of sigma receptors results in oxidation of a cysteine residue on VMAT2, which decreases transporter function. Unilateral injections of the sigma receptor antagonist BD-1063 prior to METH administration increased dopamine-related ipsilateral circling behavior, indicating the involvement of sigma receptors. These findings suggest that interactions between METH and the sigma receptor lead to oxidative species (most likely superoxide) that in turn oxidize VMAT2. Altogether, these findings show that the sigma receptor has a key role in METH dysregulation of dopamine release and dopamine-related behaviors.
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Affiliation(s)
- David M Hedges
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah, USA
| | - J Daniel Obray
- Department of Psychology and Neuroscience, Brigham Young University, Provo, UT, USA
| | - Jordan T Yorgason
- Department of Psychology and Neuroscience, Brigham Young University, Provo, UT, USA
| | - Eun Young Jang
- Department of Psychology and Neuroscience, Brigham Young University, Provo, UT, USA
| | - Vajira K Weerasekara
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah, USA
| | - Joachim D Uys
- Department of Cell and Molecular Pharmacology, Medical University of South Carolina, Charleston, SC, USA
| | - Frederick P Bellinger
- Department of Cell and Molecular Biology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Scott C Steffensen
- Department of Psychology and Neuroscience, Brigham Young University, Provo, UT, USA,Department of Psychology and Neuroscience, Brigham Young University, 1050 SWKT, Provo UT 84602, USA, Tel: +1-801-422-9499, Fax: +1-801-422-0602, E-mail:
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Valian N, Ahmadiani A, Dargahi L. Does Repeated Methamphetamine Exposure at Different Regimens Cause Parkinsonian-Like Behavior in Rats? IRANIAN JOURNAL OF PHARMACEUTICAL RESEARCH : IJPR 2018; 17:543-552. [PMID: 29881412 PMCID: PMC5985172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Methamphetamine (MA), a highly addictive psychostimulant, produces long-lasting neurotoxic effects well proven in nigrostriatal dopaminergic neurons. Considering the similarities between pathological profile of MA neurotoxicity and Parkinson's disease (PD), some reports show that previous MA abusers will be at greater risk of PD-like motor deficits. To answer the question if repeated MA exposure causes parkinsonian-like behavior in rats, we used three regimens of MA administration and assessed the motor performance parameters immediately and over a long period after MA discontinuation. Male Wistar rats in two experimental groups were treated with escalating paradigms consisting of twice daily intraperitoneal injection of either 1-7 mg/kg or 1-14 mg/kg of MA over 14 days. The third group received twice-daily doses of 15 mg/kg of MA every other day for total number of 7 days. At the 1st, 7th, 14th, 21st, 28th, and 60th days after last injections, motor activities were evaluated using narrow beam, pole, and rotarod tests. Locomotor activity was also evaluated using open field test. Repeated-measures ANOVA indicated that over the two months period following MA exposure, drug-treated rats perform beam, pole, and rotarod tests equally well as their corresponding vehicle-treated controls. Comparison of the locomotor activity didn't show significant differences between groups. These data indicated that MA at these regimens does not cause PD-related motor deficits in rats. Since MA doses, exposure duration, and dosing intervals have been shown to affect MA-induced dopaminergic toxicity, it can be concluded that none of these regimens; are strong enough to produce measurable behavioral motor deficits in rat.
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Affiliation(s)
- Neda Valian
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Abolhassan Ahmadiani
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Leila Dargahi
- Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Corresponding author: E-mail:
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Linking Stress, Catecholamine Autotoxicity, and Allostatic Load with Neurodegenerative Diseases: A Focused Review in Memory of Richard Kvetnansky. Cell Mol Neurobiol 2017; 38:13-24. [PMID: 28488009 DOI: 10.1007/s10571-017-0497-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 04/27/2017] [Indexed: 12/21/2022]
Abstract
In this Focused Review, we provide an update about evolving concepts that may link chronic stress and catecholamine autotoxicity with neurodegenerative diseases such as Parkinson's disease. Richard Kvetnansky's contributions to the field of stress and catecholamine systems inspired some of the ideas presented here. We propose that coordination of catecholaminergic systems mediates adjustments maintaining health and that senescence-related disintegration of these systems leads to disorders of regulation and to neurodegenerative diseases such as Parkinson's disease. Chronically repeated episodes of stress-related catecholamine release and reuptake, with attendant increases in formation of the toxic dopamine metabolite 3,4-dihydroxyphenylacetaldehyde, might accelerate this process.
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Association analysis of polymorphisms in VMAT2 and TMEM106B genes for Parkinson's disease, amyotrophic lateral sclerosis and multiple system atrophy. J Neurol Sci 2017; 377:65-71. [PMID: 28477711 DOI: 10.1016/j.jns.2017.03.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 03/17/2017] [Accepted: 03/20/2017] [Indexed: 02/05/2023]
Abstract
BACKGROUND The vesicular monoamine transporter type 2 (VMAT2) and transmembrane Protein 106B (TMEM106B) were reported to be associated with neurodegenerative diseases. Recent studies found that two polymorphisms (rs363371 and rs363324) in VMAT2 might be a risk factor for Parkinson's disease (PD) in Caucasians, while the two other variants (rs1990622 and rs3173615) in TMEM106B increased the risk for frontotemporal dementia (FTD). Considering the overlap between clinical manifestation and pathologic characteristics in neurodegenerative diseases, we conducted a large-sample study to investigate the associations between these four polymorphisms and the risk for PD, sporadic amyotrophic lateral sclerosis (SALS), and multiple system atrophy (MSA) in a Chinese patient population. METHODS A total of 1121 PD, 863 SALS, and 356 MSA patients, as well as 829 healthy controls (HCs), were included in the study. These four polymorphisms were genotyped using Sequenom iPLEX Assay technology. RESULTS Significant differences were found in the genotype distribution of VMAT2 rs363371 between SALS patients and HCs (p=0.001). In an additive model, "GG" of rs363371 significantly decreased the risk for SALS (p<0.001, OR: 0.49, 95% CI [0.36-0.67]). The frequencies of minor alleles for rs1990622 and rs3173615 in TMEM106B were significantly different between PD patients with initial symptoms of tremor and rigidity/bradykinesia (p=0.001), and between patients with initial symptom of rigidity/bradykinesia and HCs (p<0.001). The minor alleles "T" of rs1990622 and "C" of rs3173615 increased the risk for PD patients with initial symptom of rigidity/bradykinesia (OR: 1.21[1.10-1.34] and OR: 1.19[1.07-1.31], respectively). No differences were found in the genotype distribution and allele frequency of the four polymorphisms between MSA patients and HCs. CONCLUSION In this Chinese patient population, "GG" of rs363371 in VMAT2 may reduce the risk for SALS, while minor alleles of rs1990622 and rs3173615 in TMEM106B may be associated with PD patients with initial symptom of rigidity/bradykinesia.
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Valian N, Ahmadiani A, Dargahi L. Escalating Methamphetamine Regimen Induces Compensatory Mechanisms, Mitochondrial Biogenesis, and GDNF Expression, in Substantia Nigra. J Cell Biochem 2017; 118:1369-1378. [PMID: 27862224 DOI: 10.1002/jcb.25795] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 11/14/2016] [Indexed: 12/22/2022]
Abstract
Methamphetamine (MA) produces long-lasting deficits in dopaminergic neurons in the long-term use via several neurotoxic mechanisms. The effects of MA on mitochondrial biogenesis is less studied currently. So, we evaluated the effects of repeated escalating MA regimen on transcriptional factors involved in mitochondrial biogenesis and glial-derived neurotrophic factor (GDNF) expression in substantia nigra (SN) and striatum of rat. In male Wistar rats, increasing doses of MA (1-14 mg/kg) were administrated twice a day for 14 days. At the 1st, 14th, 28th, and 60th days after MA discontinuation, we measured the PGC1α, TFAM and NRF1 mRNA levels, indicator of mitochondrial biogenesis, and GDNF expression in SN and striatum. Furthermore, we evaluated the glial fibrillary acidic protein (GFAP) and Iba1 mRNA levels, and the levels of tyrosine hydroxylase (TH) and α-synuclein (α-syn) using immunohistochemistry and real-time polymerase chain reaction (PCR). We detected increments in PGC1α and TFAM mRNA levels in SN, but not striatum, and elevations in GDNF levels in SN immediately after MA discontinuation. We also observed increases in GFAP and Iba1 mRNA levels in SN on day 1 and increases in Iba1 mRNA on days 1 and 14 in striatum. Data analysis revealed that the number of TH+ cells in the SN did not reduce in any time points, though TH mRNA levels was increased on day 1 after MA discontinuation in SN. These data show that repeated escalating MA induces several compensatory mechanisms, such as mitochondrial biogenesis and elevation in GDNF in SN. These mechanisms can reverse MA-induced neuroinflammation and prevent TH-immunoreactivity reduction in nigrostriatal pathway. J. Cell. Biochem. 118: 1369-1378, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Neda Valian
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abolhassan Ahmadiani
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Leila Dargahi
- Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Lohr KM, Masoud ST, Salahpour A, Miller GW. Membrane transporters as mediators of synaptic dopamine dynamics: implications for disease. Eur J Neurosci 2017; 45:20-33. [PMID: 27520881 PMCID: PMC5209277 DOI: 10.1111/ejn.13357] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/12/2016] [Accepted: 08/02/2016] [Indexed: 12/14/2022]
Abstract
Dopamine was first identified as a neurotransmitter localized to the midbrain over 50 years ago. The dopamine transporter (DAT; SLC6A3) and the vesicular monoamine transporter 2 (VMAT2; SLC18A2) are regulators of dopamine homeostasis in the presynaptic neuron. DAT transports dopamine from the extracellular space into the cytosol of the presynaptic terminal. VMAT2 then packages this cytosolic dopamine into vesicular compartments for subsequent release upon neurotransmission. Thus, DAT and VMAT2 act in concert to move the transmitter efficiently throughout the neuron. Accumulation of dopamine in the neuronal cytosol can trigger oxidative stress and neurotoxicity, suggesting that the proper compartmentalization of dopamine is critical for neuron function and risk of disease. For decades, studies have examined the effects of reduced transporter function in mice (e.g. DAT-KO, VMAT2-KO, VMAT2-deficient). However, we have only recently been able to assess the effects of elevated transporter expression using BAC transgenic methods (DAT-tg, VMAT2-HI mice). Complemented with in vitro work and neurochemical techniques to assess dopamine compartmentalization, a new focus on the importance of transporter proteins as both models of human disease and potential drug targets has emerged. Here, we review the importance of DAT and VMAT2 function in the delicate balance of neuronal dopamine.
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Affiliation(s)
- Kelly M Lohr
- Department of Environmental Health, Rollins School of Public Health, Emory University, 1518 Clifton Road, Atlanta, GA, 30322, USA
| | - Shababa T Masoud
- Department of Pharmacology and Toxicology, University of Toronto, ON, Canada
| | - Ali Salahpour
- Department of Pharmacology and Toxicology, University of Toronto, ON, Canada
| | - Gary W Miller
- Department of Environmental Health, Rollins School of Public Health, Emory University, 1518 Clifton Road, Atlanta, GA, 30322, USA
- Center for Neurodegenerative Diseases, Emory University, Atlanta, GA, USA
- Department of Pharmacology, Emory University, Atlanta, GA, USA
- Department of Neurology, Emory University, Atlanta, GA, USA
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Association of SNPs in dopamine and serotonin pathway genes and their interacting genes with temperament traits in Charolais cows. J Appl Genet 2016; 58:363-371. [PMID: 27987181 DOI: 10.1007/s13353-016-0383-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 09/26/2016] [Accepted: 11/24/2016] [Indexed: 10/20/2022]
Abstract
Cattle temperament is a complex trait, and molecular studies aimed at defining this trait are scarce. We used an interaction networks approach to identify new genes (interacting genes) and to estimate their effects and those of 19 dopamine- and serotonin-related genes on the temperament traits of Charolais cattle. The genes proopiomelanocortin (POMC), neuropeptide Y (NPY), solute carrier family 18, member 2 (SLC18A2) and FBJ murine osteosarcoma viral oncogene homologue (FOSFBJ) were identified as new candidates. Their potential to be associated with temperament was estimated according to their reported biological activities, which included interactions with neural activity, receptor function, targeting or synthesis of neurotransmitters and association with behaviour. Pen score (PS) and exit velocity (EV) measures were determined from 412 Charolais cows to calculate their temperament score (TS). Based on the TS, calm (n = 55; TS, 1.09 ± 0.33) and temperamental (n = 58; TS, 2.27 ± 0.639) cows were selected and genotyped using a 248 single-nucleotide variation (SNV) panel. Of the 248 variations in the panel, only 151 were confirmed to be polymorphic (single-nucleotide polymorphisms; SNPs) in the tested population. Single-marker association analyses between genotypes and temperament measures (EV, PS and/or TS) indicated significant associations of six SNPs from four candidate genes. The markers rs109576799 and rs43696138, located in the DRD3 and HTR2A genes, respectively, were significantly associated with both EV and TS traits. Four markers, rs110365063 and rs137756569 from the POMC gene and rs110365063 and rs135155082 located in SLC18A2 and DRD2, respectively, were associated with PS. The variant rs110365063 located in bovine SLC18A2 causes a change in the amino acid sequence from Ala to Thr. Further studies are needed to confirm the association of genetic profile with cattle temperament; however, our study represents important progress in understanding the regulation of cattle temperament by different genes with divergent functions.
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Cliburn RA, Dunn AR, Stout KA, Hoffman CA, Lohr KM, Bernstein AI, Winokur EJ, Burkett J, Schmitz Y, Caudle WM, Miller GW. Immunochemical localization of vesicular monoamine transporter 2 (VMAT2) in mouse brain. J Chem Neuroanat 2016; 83-84:82-90. [PMID: 27836486 DOI: 10.1016/j.jchemneu.2016.11.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 10/31/2016] [Accepted: 11/04/2016] [Indexed: 12/16/2022]
Abstract
Vesicular monoamine transporter 2 (VMAT2, SLC18A2) is a transmembrane transporter protein that packages dopamine, serotonin, norepinephrine, and histamine into vesicles in preparation for neurotransmitter release from the presynaptic neuron. VMAT2 function and related vesicle dynamics have been linked to susceptibility to oxidative stress, exogenous toxicants, and Parkinson's disease. To address a recent depletion of commonly used antibodies to VMAT2, we generated and characterized a novel rabbit polyclonal antibody generated against a 19 amino acid epitope corresponding to an antigenic sequence within the C-terminal tail of mouse VMAT2. We used genetic models of altered VMAT2 expression to demonstrate that the antibody specifically recognizes VMAT2 and localizes to synaptic vesicles. Furthermore, immunohistochemical labeling using this VMAT2 antibody produces immunoreactivity that is consistent with expected VMAT2 regional distribution. We show the distribution of VMAT2 in monoaminergic brain regions of mouse brain, notably the midbrain, striatum, olfactory tubercle, dopaminergic paraventricular nuclei, tuberomammillary nucleus, raphe nucleus, and locus coeruleus. Normal neurotransmitter vesicle dynamics are critical for proper health and functioning of the nervous system, and this well-characterized VMAT2 antibody will be a useful tool in studying neurodegenerative and neuropsychiatric conditions characterized by vesicular dysfunction.
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Affiliation(s)
- Rachel A Cliburn
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, United States.
| | - Amy R Dunn
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, United States
| | - Kristen A Stout
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, United States
| | - Carlie A Hoffman
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, United States
| | - Kelly M Lohr
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, United States
| | - Alison I Bernstein
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, United States
| | - Emily J Winokur
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, United States
| | - James Burkett
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, United States
| | - Yvonne Schmitz
- Department of Neurology, Columbia University Medical Center, New York City, NY 10032, United States
| | - William M Caudle
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, United States
| | - Gary W Miller
- Department of Environmental Health, Rollins School of Public Health, Department of Pharmacology, Department of Neurology, Center for Neurodegenerative Diseases, Emory University, Atlanta, GA 30322, United States.
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Lohr KM, Chen M, Hoffman CA, McDaniel MJ, Stout KA, Dunn AR, Wang M, Bernstein AI, Miller GW. Vesicular Monoamine Transporter 2 (VMAT2) Level Regulates MPTP Vulnerability and Clearance of Excess Dopamine in Mouse Striatal Terminals. Toxicol Sci 2016; 153:79-88. [PMID: 27287315 DOI: 10.1093/toxsci/kfw106] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The vesicular monoamine transporter 2 (VMAT2) packages neurotransmitters for release during neurotransmission and sequesters toxicants into vesicles to prevent neuronal damage. In mice, low VMAT2 levels causes catecholaminergic cell loss and behaviors resembling Parkinson's disease, while high levels of VMAT2 increase dopamine release and protect against dopaminergic toxicants. However, comparisons across these VMAT2 mouse genotypes were impossible due to the differing genetic background strains of the animals. Following back-crossing to a C57BL/6 line, we confirmed that mice with approximately 95% lower VMAT2 levels compared with wild-type (VMAT2-LO) display significantly reduced vesicular uptake, progressive dopaminergic terminal loss with aging, and exacerbated 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity. Conversely, VMAT2-overexpressing mice (VMAT2-HI) are protected from the loss of striatal terminals following MPTP treatment. We also provide evidence that enhanced vesicular filling in the VMAT2-HI mice modifies the handling of newly synthesized dopamine, indicated by changes in indirect measures of extracellular dopamine clearance. These results confirm the role of VMAT2 in the protection of vulnerable nigrostriatal dopamine neurons and may also provide new insight into the side effects of L-DOPA treatments in Parkinson's disease.
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Affiliation(s)
- Kelly M Lohr
- *Department of Environmental Health, Rollins School of Public Health
| | - Merry Chen
- *Department of Environmental Health, Rollins School of Public Health
| | - Carlie A Hoffman
- *Department of Environmental Health, Rollins School of Public Health
| | | | - Kristen A Stout
- *Department of Environmental Health, Rollins School of Public Health
| | - Amy R Dunn
- *Department of Environmental Health, Rollins School of Public Health
| | - Minzheng Wang
- *Department of Environmental Health, Rollins School of Public Health
| | | | - Gary W Miller
- *Department of Environmental Health, Rollins School of Public Health Center for Neurodegenerative Diseases Department of Pharmacology Department of Neurology, Emory University, Atlanta, Georgia, 30322
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Phillips TJ, Mootz JRK, Reed C. Identification of Treatment Targets in a Genetic Mouse Model of Voluntary Methamphetamine Drinking. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 126:39-85. [PMID: 27055611 DOI: 10.1016/bs.irn.2016.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Methamphetamine has powerful stimulant and euphoric effects that are experienced as rewarding and encourage use. Methamphetamine addiction is associated with debilitating illnesses, destroyed relationships, child neglect, violence, and crime; but after many years of research, broadly effective medications have not been identified. Individual differences that may impact not only risk for developing a methamphetamine use disorder but also affect treatment response have not been fully considered. Human studies have identified candidate genes that may be relevant, but lack of control over drug history, the common use or coabuse of multiple addictive drugs, and restrictions on the types of data that can be collected in humans are barriers to progress. To overcome some of these issues, a genetic animal model comprised of lines of mice selectively bred for high and low voluntary methamphetamine intake was developed to identify risk and protective alleles for methamphetamine consumption, and identify therapeutic targets. The mu opioid receptor gene was supported as a target for genes within a top-ranked transcription factor network associated with level of methamphetamine intake. In addition, mice that consume high levels of methamphetamine were found to possess a nonfunctional form of the trace amine-associated receptor 1 (TAAR1). The Taar1 gene is within a mouse chromosome 10 quantitative trait locus for methamphetamine consumption, and TAAR1 function determines sensitivity to aversive effects of methamphetamine that may curb intake. The genes, gene interaction partners, and protein products identified in this genetic mouse model represent treatment target candidates for methamphetamine addiction.
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Affiliation(s)
- T J Phillips
- Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, United States; Veterans Affairs Portland Health Care System, Portland, OR, United States.
| | - J R K Mootz
- Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, United States
| | - C Reed
- Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, United States
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Deficits in coordinated motor behavior and in nigrostriatal dopaminergic system ameliorated and VMAT2 expression up-regulated in aged male rats by administration of testosterone propionate. Exp Gerontol 2016; 78:1-11. [PMID: 26956479 DOI: 10.1016/j.exger.2016.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 02/23/2016] [Accepted: 03/02/2016] [Indexed: 12/16/2022]
Abstract
The effects of testosterone propionate (TP) supplements on the coordinated motor behavior and nigrostriatal dopaminergic (NSDA) system were analyzed in aged male rats. The present study showed the coordinated motor behavioral deficits, the reduced activity of NSDA system and the decreased expression of vesicular monoamine transporter 2 (VMAT2) in 24 month-old male rats. Long term TP treatment improved the motor coordination dysfunction with aging. Increased tyrosine hydroxylase and dopamine transporter, as well as dopamine and its metabolites were found in the NSDA system of TP-treated 24 month-old male rats, indicative of the amelioratory effects of TP supplements on NSDA system of aged male rats. The enhancement of dopaminergic (DAergic) activity of NSDA system by TP supplements might underlie the amelioration of the coordinated motor dysfunction in aged male rats. TP supplements up-regulated VMAT2 expression in NSDA system of aged male rats. Up-regulation of VMAT2 expression in aged male rats following chronic TP treatment might be involved in the maintenance of DAergic function of NSDA system in aged male rats.
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