1
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Hasuzawa N, Moriyama S, Wang L, Nagayama A, Ashida K, Moriyama Y, Nomura M. Quinacrine is not a vital fluorescent probe for vesicular ATP storage. Purinergic Signal 2021; 17:725-735. [PMID: 34713379 DOI: 10.1007/s11302-021-09820-8] [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: 08/02/2021] [Accepted: 09/27/2021] [Indexed: 10/20/2022] Open
Abstract
Quinacrine, a fluorescent amphipathic amine, has been used as a vital fluorescent probe to visualize vesicular storage of ATP in the field of purinergic signaling. However, the mechanism(s) by which quinacrine represents vesicular ATP storage remains to be clarified. The present study investigated the validity of the use of quinacrine as a vial fluorescent probe for ATP-storing organelles. Vesicular nucleotide transporter (VNUT), an essential component for vesicular storage and ATP release, is present in very low density lipoprotein (VLDL)-containing secretory vesicles in hepatocytes. VNUT gene knockout (Vnut-/-) or clodronate treatment, a VNUT inhibitor, disappeared vesicular ATP release (Tatsushima et al., Biochim Biophys Acta Molecular Basis of Disease 2021, e166013). Upon incubation of mice's primary hepatocytes, quinacrine accumulates in a granular pattern into the cytoplasm, sensitive to 0.1-μM bafilomycin A1, a vacuolar ATPase (V-ATPase) inhibitor. Neither Vnut-/- nor treatment of clodronate affected quinacrine granular accumulation. In vitro, quinacrine is accumulated into liposomes upon imposing inside acidic transmembranous pH gradient (∆pH) irrespective of the presence or absence of ATP. Neither ATP binding on VNUT nor VNUT-mediated uptake of ATP was affected by quinacrine. Consistently, VNUT-mediated uptake of quinacrine was negligible or under the detection limit. From these results, it is concluded that vesicular quinacrine accumulation is not due to a consequence of its interaction with ATP but due to ∆pH-driven concentration across the membranes as an amphipathic amine. Thus, quinacrine is not a vital fluorescent probe for vesicular ATP storage.
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Affiliation(s)
- Nao Hasuzawa
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, 67 Asahi-machi, Kurume, 830-0011, Japan
| | - Sawako Moriyama
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, 67 Asahi-machi, Kurume, 830-0011, Japan
| | - Lixiang Wang
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume, 830-0011, Japan
| | - Ayako Nagayama
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, 67 Asahi-machi, Kurume, 830-0011, Japan
| | - Kenji Ashida
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, 67 Asahi-machi, Kurume, 830-0011, Japan
| | - Yoshinori Moriyama
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, 67 Asahi-machi, Kurume, 830-0011, Japan.
| | - Masatoshi Nomura
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, 67 Asahi-machi, Kurume, 830-0011, Japan
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2
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Provencher BA, Eshleman AJ, Johnson RA, Shi X, Kryatova O, Nelson J, Tian J, Gonzalez M, Meltzer PC, Janowsky A. Synthesis and Discovery of Arylpiperidinylquinazolines: New Inhibitors of the Vesicular Monoamine Transporter. J Med Chem 2018; 61:9121-9131. [PMID: 30240563 DOI: 10.1021/acs.jmedchem.8b00542] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Methamphetamine, a human vesicular monoamine transporter 2 (VMAT2) substrate, releases dopamine, serotonin, and norepinephrine from vesicles into the cytosol of presynaptic neurons and induces reverse transport by the monoamine transporters to increase extracellular neurotransmitters. Currently available radioligands for VMAT2 have considerable liabilities: The binding of [3H]dihydrotetrabenazine ([3H]DHTB) to a site on VMAT2 is not dependent on ATP, and [3H]reserpine binds almost irreversibly to VMAT2. Herein we demonstrate that several arylpiperidinylquinazolines (APQs) are potent inhibitors of [3H]reserpine binding at recombinant human VMAT2 expressed in HEK-293 cells. These compounds are biodiastereoselective and bioenantioselective. The lead radiolabeled APQ is unique because it binds reversibly to VMAT2 but does not bind the [3H]DHTB binding site. Furthermore, experimentation shows that several novel APQ ligands have high potency for inhibition of uptake by both HEK-VMAT2 cells and mouse striatal vesicles and may be useful tools for characterizing drug-induced effects on human VMAT2 expression and function.
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Affiliation(s)
- Brian A Provencher
- Organix Inc , 240 Salem Street , Woburn , Massachusetts 01801 , United States.,Department of Chemistry and Biochemistry , Merrimack College , North Andover , Massachusetts 01845 , United States
| | - Amy J Eshleman
- Research Service , VA Portland Health Care System , Portland , Oregon 97239 , United States.,Departments of Psychiatry and Behavioral Neuroscience , Oregon Health and Science University , Portland , Oregon 97239 , United States
| | - Robert A Johnson
- Research Service , VA Portland Health Care System , Portland , Oregon 97239 , United States
| | - Xiao Shi
- Research Service , VA Portland Health Care System , Portland , Oregon 97239 , United States.,Departments of Psychiatry and Behavioral Neuroscience , Oregon Health and Science University , Portland , Oregon 97239 , United States
| | - Olga Kryatova
- Organix Inc , 240 Salem Street , Woburn , Massachusetts 01801 , United States
| | - Jared Nelson
- Organix Inc , 240 Salem Street , Woburn , Massachusetts 01801 , United States
| | - Jianhua Tian
- Organix Inc , 240 Salem Street , Woburn , Massachusetts 01801 , United States
| | - Mario Gonzalez
- Organix Inc , 240 Salem Street , Woburn , Massachusetts 01801 , United States
| | - Peter C Meltzer
- Organix Inc , 240 Salem Street , Woburn , Massachusetts 01801 , United States
| | - Aaron Janowsky
- Research Service , VA Portland Health Care System , Portland , Oregon 97239 , United States.,Departments of Psychiatry and Behavioral Neuroscience , Oregon Health and Science University , Portland , Oregon 97239 , United States.,The Methamphetamine Abuse Research Center , Oregon Health and Science University , Portland , Oregon 97239 , United States
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3
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Dunn M, Henke A, Clark S, Kovalyova Y, Kempadoo KA, Karpowicz RJ, Kandel ER, Sulzer D, Sames D. Designing a norepinephrine optical tracer for imaging individual noradrenergic synapses and their activity in vivo. Nat Commun 2018; 9:2838. [PMID: 30026491 PMCID: PMC6053466 DOI: 10.1038/s41467-018-05075-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 05/11/2018] [Indexed: 11/14/2022] Open
Abstract
Norepinephrine is a monoamine neurotransmitter with a wide repertoire of physiological roles in the peripheral and central nervous systems. There are, however, no experimental means to study functional properties of individual noradrenergic synapses in the brain. Development of new approaches for imaging synaptic neurotransmission is of fundamental importance to study specific synaptic changes that occur during learning, behavior, and pathological processes. Here, we introduce fluorescent false neurotransmitter 270 (FFN270), a fluorescent tracer of norepinephrine. As a fluorescent substrate of the norepinephrine and vesicular monoamine transporters, FFN270 labels noradrenergic neurons and their synaptic vesicles, and enables imaging synaptic vesicle content release from specific axonal sites in living rodents. Combining FFN270 imaging and optogenetic stimulation, we find heterogeneous release properties of noradrenergic synapses in the somatosensory cortex, including low and high releasing populations. Through systemic amphetamine administration, we observe rapid release of cortical noradrenergic vesicular content, providing insight into the drug’s effect. The noradrenergic system plays numerous physiological roles but tools to study it are scarce. Here the authors develop a fluorescent analogue of norepinephrine that can be used to label noradrenergic neurons and the synaptic vesicles, and use it to measure single synaptic vesicle release sites in living mice.
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Affiliation(s)
- Matthew Dunn
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Adam Henke
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Samuel Clark
- Department of Neurology, Columbia University, New York, NY, 10032, USA.,Department of Psychiatry, Columbia University, New York, NY, 10032, USA.,Department of Pharmacology, Columbia University, New York, NY, 10032, USA
| | | | | | | | - Eric R Kandel
- Department of Psychiatry, Columbia University, New York, NY, 10032, USA.,Department of Neuroscience, Columbia University, New York, NY, 10032, USA.,Kavli Institute for Brain Science, New York, NY, 10032, USA.,Howard Hughes Medical Institute, New York, NY, 10032, USA
| | - David Sulzer
- Department of Neurology, Columbia University, New York, NY, 10032, USA. .,Department of Psychiatry, Columbia University, New York, NY, 10032, USA. .,Department of Pharmacology, Columbia University, New York, NY, 10032, USA.
| | - Dalibor Sames
- Department of Chemistry, Columbia University, New York, NY, 10027, USA.
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4
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Henke A, Kovalyova Y, Dunn M, Dreier D, Gubernator NG, Dincheva I, Hwu C, Šebej P, Ansorge MS, Sulzer D, Sames D. Toward Serotonin Fluorescent False Neurotransmitters: Development of Fluorescent Dual Serotonin and Vesicular Monoamine Transporter Substrates for Visualizing Serotonin Neurons. ACS Chem Neurosci 2018; 9:925-934. [PMID: 29281252 PMCID: PMC6342556 DOI: 10.1021/acschemneuro.7b00320] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Ongoing efforts in our laboratories focus on design of optical reporters known as fluorescent false neurotransmitters (FFNs) that enable the visualization of uptake into, packaging within, and release from individual monoaminergic neurons and presynaptic sites in the brain. Here, we introduce the molecular probe FFN246 as an expansion of the FFN platform to the serotonergic system. Combining the acridone fluorophore with the ethylamine recognition element of serotonin, we identified FFN54 and FFN246 as substrates for both the serotonin transporter and the vesicular monoamine transporter 2 (VMAT2). A systematic structure-activity study revealed the basic structural chemotype of aminoalkyl acridones required for serotonin transporter (SERT) activity and enabled lowering the background labeling of these probes while maintaining SERT activity, which proved essential for obtaining sufficient signal in the brain tissue (FFN246). We demonstrate the utility of FFN246 for direct examination of SERT activity and SERT inhibitors in 96-well cell culture assays, as well as specific labeling of serotonergic neurons of the dorsal raphe nucleus in the living tissue of acute mouse brain slices. While we found only minor FFN246 accumulation in serotonergic axons in murine brain tissue, FFN246 effectively traces serotonin uptake and packaging in the soma of serotonergic neurons with improved photophysical properties and loading parameters compared to known serotonin-based fluorescent tracers.
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Affiliation(s)
- Adam Henke
- Department of Chemistry and Neuro Technology Center at Columbia University , New York , New York 10027 , United States
| | - Yekaterina Kovalyova
- Department of Chemistry and Neuro Technology Center at Columbia University , New York , New York 10027 , United States
| | - Matthew Dunn
- Department of Chemistry and Neuro Technology Center at Columbia University , New York , New York 10027 , United States
| | - Dominik Dreier
- Department of Chemistry and Neuro Technology Center at Columbia University , New York , New York 10027 , United States
| | - Niko G Gubernator
- Department of Chemistry and Neuro Technology Center at Columbia University , New York , New York 10027 , United States
| | - Iva Dincheva
- Department of Psychiatry , Columbia University , New York , New York 10032 , United States
| | - Christopher Hwu
- Department of Chemistry and Neuro Technology Center at Columbia University , New York , New York 10027 , United States
| | - Peter Šebej
- Department of Chemistry and Neuro Technology Center at Columbia University , New York , New York 10027 , United States
| | - Mark S Ansorge
- Department of Psychiatry , Columbia University , New York , New York 10032 , United States
| | - David Sulzer
- Department of Psychiatry , Columbia University , New York , New York 10032 , United States
- Department of Neurology , Columbia University , New York , New York 10032 , United States
- Department of Pharmacology , Columbia University , New York , New York 10032 , United States
| | - Dalibor Sames
- Department of Chemistry and Neuro Technology Center at Columbia University , New York , New York 10027 , United States
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5
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Gemechu JM, Sharma A, Yu D, Xie Y, Merkel OM, Moszczynska A. Characterization of Dopaminergic System in the Striatum of Young Adult Park2 -/- Knockout Rats. Sci Rep 2018; 8:1517. [PMID: 29367643 PMCID: PMC5784013 DOI: 10.1038/s41598-017-18526-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 11/20/2017] [Indexed: 12/13/2022] Open
Abstract
Mutations in parkin gene (Park2) are linked to early-onset autosomal recessive Parkinson's disease (PD) and young-onset sporadic PD. Park2 knockout (PKO) rodents; however, do not display neurodegeneration of the nigrostriatal pathway, suggesting age-dependent compensatory changes. Our goal was to examine dopaminergic (DAergic) system in the striatum of 2 month-old PKO rats in order to characterize compensatory mechanisms that may have occurred within the system. The striata form wild type (WT) and PKO Long Evans male rats were assessed for the levels of DAergic markers, for monoamine oxidase (MAO) A and B activities and levels, and for the levels of their respective preferred substrates, serotonin (5-HT) and ß-phenylethylamine (ß-PEA). The PKO rats displayed lower activities of MAOs and higher levels of ß-PEA in the striatum than their WT counterparts. Decreased levels of ß-PEA receptor, trace amine-associated receptor 1 (TAAR-1), and postsynaptic DA D2 (D2L) receptor accompanied these alterations. Drug-naive PKO rats displayed normal locomotor activity; however, they displayed decreased locomotor response to a low dose of psychostimulant methamphetamine, suggesting altered DAergic neurotransmission in the striatum when challenged with an indirect agonist. Altogether, our findings suggest that 2 month-old PKO male rats have altered DAergic and trace aminergic signaling.
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Affiliation(s)
- Jickssa M Gemechu
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, USA
- Department of Biomedical Sciences, OUWB School of Medicine, Rochester, MI, USA
| | - Akhil Sharma
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, USA
| | - Dongyue Yu
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, USA
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, USA
| | - Yuran Xie
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, USA
- Boston Biomedical Inc., Allston, MA, USA
| | - Olivia M Merkel
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, USA
- Department of Pharmacy, Ludwig-Maximilians University of Munich, Munich, Germany
| | - Anna Moszczynska
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, USA.
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6
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Wimalasena K. Current Status, Gaps, and Weaknesses of the Mechanism of Selective Dopaminergic Toxicity of MPTP/MPP +. ADVANCES IN MOLECULAR TOXICOLOGY 2017. [DOI: 10.1016/b978-0-12-812522-9.00003-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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7
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Pereira DB, Schmitz Y, Mészáros J, Merchant P, Hu G, Li S, Henke A, Lizardi-Ortiz JE, Karpowicz RJ, Morgenstern TJ, Sonders MS, Kanter E, Rodriguez PC, Mosharov EV, Sames D, Sulzer D. Fluorescent false neurotransmitter reveals functionally silent dopamine vesicle clusters in the striatum. Nat Neurosci 2016; 19:578-86. [PMID: 26900925 PMCID: PMC4853199 DOI: 10.1038/nn.4252] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 01/15/2016] [Indexed: 12/16/2022]
Abstract
Neurotransmission at dopaminergic synapses has been studied with techniques that provide high temporal resolution, but cannot resolve individual synapses. To elucidate the spatial dynamics and heterogeneity of individual dopamine boutons, we developed fluorescent false neurotransmitter 200 (FFN200), a vesicular monoamine transporter 2 (VMAT2) substrate that selectively traces monoamine exocytosis in both neuronal cell culture and brain tissue. By monitoring electrically evoked Ca(2+) transients with GCaMP3 and FFN200 release simultaneously, we found that only a small fraction of dopamine boutons that exhibited Ca(2+) influx engaged in exocytosis, a result confirmed with activity-dependent loading of the endocytic probe FM1-43. Thus, only a low fraction of striatal dopamine axonal sites with uptake-competent VMAT2 vesicles are capable of transmitter release. This is consistent with the presence of functionally 'silent' dopamine vesicle clusters and represents, to the best of our knowledge, the first report suggestive of presynaptically silent neuromodulatory synapses.
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Affiliation(s)
- Daniela B. Pereira
- Department of Neurology, Columbia University Medical Center, New York, NY
| | - Yvonne Schmitz
- Department of Neurology, Columbia University Medical Center, New York, NY
| | - József Mészáros
- Department of Psychiatry, Columbia University Medical Center, New York, NY
| | | | - Gang Hu
- Department of Chemistry, Columbia University, New York, NY
| | - Shu Li
- Department of Chemistry, Columbia University, New York, NY
| | - Adam Henke
- Department of Chemistry, Columbia University, New York, NY
| | | | | | | | - Mark S. Sonders
- Department of Neurology, Columbia University Medical Center, New York, NY
- Department of Psychiatry, Columbia University Medical Center, New York, NY
| | - Ellen Kanter
- Department of Neurology, Columbia University Medical Center, New York, NY
| | | | - Eugene V. Mosharov
- Department of Neurology, Columbia University Medical Center, New York, NY
| | - Dalibor Sames
- Department of Chemistry, Columbia University, New York, NY
| | - David Sulzer
- Department of Neurology, Columbia University Medical Center, New York, NY
- Department of Psychiatry, Columbia University Medical Center, New York, NY
- Department of Pharmacology, Columbia University Medical Center, New York, NY
- Department of Neuroscience, New York Psychiatric Institute, New York, NY
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8
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Freyberg Z, Sonders MS, Aguilar JI, Hiranita T, Karam CS, Flores J, Pizzo AB, Zhang Y, Farino ZJ, Chen A, Martin CA, Kopajtic TA, Fei H, Hu G, Lin YY, Mosharov EV, McCabe BD, Freyberg R, Wimalasena K, Hsin LW, Sames D, Krantz DE, Katz JL, Sulzer D, Javitch JA. Mechanisms of amphetamine action illuminated through optical monitoring of dopamine synaptic vesicles in Drosophila brain. Nat Commun 2016; 7:10652. [PMID: 26879809 PMCID: PMC4757768 DOI: 10.1038/ncomms10652] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 01/06/2016] [Indexed: 01/04/2023] Open
Abstract
Amphetamines elevate extracellular dopamine, but the underlying mechanisms remain uncertain. Here we show in rodents that acute pharmacological inhibition of the vesicular monoamine transporter (VMAT) blocks amphetamine-induced locomotion and self-administration without impacting cocaine-induced behaviours. To study VMAT's role in mediating amphetamine action in dopamine neurons, we have used novel genetic, pharmacological and optical approaches in Drosophila melanogaster. In an ex vivo whole-brain preparation, fluorescent reporters of vesicular cargo and of vesicular pH reveal that amphetamine redistributes vesicle contents and diminishes the vesicle pH-gradient responsible for dopamine uptake and retention. This amphetamine-induced deacidification requires VMAT function and results from net H+ antiport by VMAT out of the vesicle lumen coupled to inward amphetamine transport. Amphetamine-induced vesicle deacidification also requires functional dopamine transporter (DAT) at the plasma membrane. Thus, we find that at pharmacologically relevant concentrations, amphetamines must be actively transported by DAT and VMAT in tandem to produce psychostimulant effects. Amphetamines are known to enhance extracellular dopamine levels, but the underlying mechanisms are unclear. Utilising a new pH biosensor for synaptic vesicles, the authors show that amphetamines diminish vesicle pH gradients, disrupting dopamine packaging and leading to increased neurotransmitter release.
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Affiliation(s)
- Zachary Freyberg
- Department of Psychiatry, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York 10032, USA
| | - Mark S Sonders
- Department of Psychiatry, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York 10032, USA.,Department of Neurology, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA
| | - Jenny I Aguilar
- Department of Psychiatry, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York 10032, USA
| | - Takato Hiranita
- Psychobiology Section, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Caline S Karam
- Department of Psychiatry, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York 10032, USA
| | - Jorge Flores
- Department of Biochemistry and Molecular Biophysics, Howard Hughes Medical Institute, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA
| | - Andrea B Pizzo
- Department of Psychiatry, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York 10032, USA
| | - Yuchao Zhang
- Department of Psychiatry, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York 10032, USA
| | - Zachary J Farino
- Department of Psychiatry, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York 10032, USA
| | - Audrey Chen
- Department of Psychiatry and Biobehavioral Sciences and Semel Institute for Neuroscience and Human Behavior, Hatos Center for Neuropharmacology, David Geffen School of Medicine University of California, Los Angeles, California 90095, USA
| | - Ciara A Martin
- UCLA Interdepartmental Program in Molecular Toxicology, University of California, Los Angeles, California 90095, USA
| | - Theresa A Kopajtic
- Psychobiology Section, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Hao Fei
- Department of Psychiatry and Biobehavioral Sciences and Semel Institute for Neuroscience and Human Behavior, Hatos Center for Neuropharmacology, David Geffen School of Medicine University of California, Los Angeles, California 90095, USA
| | - Gang Hu
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - Yi-Ying Lin
- School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Republic of China 10055
| | - Eugene V Mosharov
- Department of Neurology, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA
| | - Brian D McCabe
- Center for Motor Neuron Biology and Disease, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA.,Department of Pathology and Cell Biology, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA.,Department of Neuroscience, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA
| | - Robin Freyberg
- Department of Psychology, Stern College for Women, Yeshiva University, New York, New York 10016, USA
| | | | - Ling-Wei Hsin
- School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Republic of China 10055
| | - Dalibor Sames
- Department of Chemistry, Columbia University, New York, New York 10027, USA
| | - David E Krantz
- Department of Psychiatry and Biobehavioral Sciences and Semel Institute for Neuroscience and Human Behavior, Hatos Center for Neuropharmacology, David Geffen School of Medicine University of California, Los Angeles, California 90095, USA
| | - Jonathan L Katz
- Psychobiology Section, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - David Sulzer
- Department of Psychiatry, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York 10032, USA.,Department of Neurology, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA.,Department of Pharmacology, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA
| | - Jonathan A Javitch
- Department of Psychiatry, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York 10032, USA.,Department of Pharmacology, College of Physicians &Surgeons, Columbia University, New York, New York 10032, USA
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9
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Ugolev Y, Segal T, Yaffe D, Gros Y, Schuldiner S. Identification of conformationally sensitive residues essential for inhibition of vesicular monoamine transport by the noncompetitive inhibitor tetrabenazine. J Biol Chem 2013; 288:32160-32171. [PMID: 24062308 DOI: 10.1074/jbc.m113.502971] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Vesicular monoamine transporter 2 (VMAT2) transports monoamines into storage vesicles in a process that involves exchange of the charged monoamine with two protons. VMAT2 is a member of the DHA12 family of multidrug transporters that belongs to the major facilitator superfamily of secondary transporters. Tetrabenazine (TBZ) is a non-competitive inhibitor of VMAT2 that is used in the treatment of hyperkinetic disorders associated with Huntington disease and Tourette syndrome. Previous biochemical studies suggested that the recognition site for TBZ and monoamines is different. However, the precise mechanism of TBZ interaction with VMAT2 remains unknown. Here we used a random mutagenesis approach and selected TBZ-resistant mutants. The mutations clustered around the lumenal opening of the transporter and mapped to either conserved proline or glycine, or to residues immediately adjacent to conserved proline and glycine. Directed mutagenesis provides further support for the essential role of the latter residues. Our data strongly suggest that the conserved α-helix breaking residues identified in this work play an important role in conformational rearrangements required for TBZ binding and substrate transport. Our results provide a novel insight into the mechanism of transport and TBZ binding by VMAT2.
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Affiliation(s)
- Yelena Ugolev
- From the Department of Biological Chemistry, Alexander A. Silberman Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Tali Segal
- From the Department of Biological Chemistry, Alexander A. Silberman Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Dana Yaffe
- From the Department of Biological Chemistry, Alexander A. Silberman Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Yael Gros
- From the Department of Biological Chemistry, Alexander A. Silberman Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Shimon Schuldiner
- From the Department of Biological Chemistry, Alexander A. Silberman Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel.
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10
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Hu G, Henke A, Karpowicz RJ, Sonders MS, Farrimond F, Edwards R, Sulzer D, Sames D. New fluorescent substrate enables quantitative and high-throughput examination of vesicular monoamine transporter 2 (VMAT2). ACS Chem Biol 2013; 8:1947-54. [PMID: 23859623 DOI: 10.1021/cb400259n] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Vesicular monoamine transporter 2 (VMAT2) is an essential component of the monoaminergic neurotransmission system in the brain as it transports monoamine neurotransmitters from the neuronal cytosol into the synaptic vesicles and thus contributes to modulation of neurotransmitter release. Considering the continuing interest in VMAT2 as a drug target, as well as a target for the design of imaging probes, we have developed a fluorescent substrate well suited for the study of VMAT2 in cell culture. Herein, we report the synthesis and characterization of a new fluorescent probe, FFN206, as an excellent VMAT2 substrate capable of detecting VMAT2 activity in intact cells using fluorescence microscopy, with subcellular localization to VMAT2-expressing acidic compartments without apparent labeling of other organelles. VMAT2 activity can also be measured via microplate reader. The apparent Km of FFN206 at VMAT2 was found to be 1.16 ± 0.10 μM, similar to that of dopamine. We further report the development and validation of a cell-based fluorescence assay amenable to high-throughput screening (HTS) using VMAT2-transfected HEK cells (Z'-factor of 0.7-0.8), enabling rapid identification of VMAT2 inhibitors and measurement of their inhibition constants over a broad range of affinities. FFN206 thus represents a new tool for optical examination of VMAT2 function in cell culture.
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Affiliation(s)
- Gang Hu
- Department
of Chemistry, Columbia University, New
York, New York 10027, United
States
| | - Adam Henke
- Department
of Chemistry, Columbia University, New
York, New York 10027, United
States
| | - Richard J. Karpowicz
- Department
of Chemistry, Columbia University, New
York, New York 10027, United
States
| | - Mark S. Sonders
- Departments of Psychiatry and
Neurology, Columbia University, New York,
New York 10032, United States
| | - Frances Farrimond
- Departments of Neurology and
Physiology, University of California School of Medicine, San Francisco, San Francisco, California 94143, United
States
| | - Robert Edwards
- Departments of Neurology and
Physiology, University of California School of Medicine, San Francisco, San Francisco, California 94143, United
States
| | - David Sulzer
- Departments of
Neurology, Psychiatry,
and Pharmacology, Columbia University,
New York, New York 10032, United States
| | - Dalibor Sames
- Department
of Chemistry, Columbia University, New
York, New York 10027, United
States
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11
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Proteoliposomes as tool for assaying membrane transporter functions and interactions with xenobiotics. Pharmaceutics 2013; 5:472-97. [PMID: 24300519 PMCID: PMC3836619 DOI: 10.3390/pharmaceutics5030472] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 08/15/2013] [Accepted: 09/04/2013] [Indexed: 02/07/2023] Open
Abstract
Proteoliposomes represent a suitable and up to date tool for studying membrane transporters which physiologically mediate absorption, excretion, trafficking and reabsorption of nutrients and metabolites. Using recently developed reconstitution strategies, transporters can be inserted in artificial bilayers with the same orientation as in the cell membranes and in the absence of other interfering molecular systems. These methodologies are very suitable for studying kinetic parameters and molecular mechanisms. After the first applications on mitochondrial transporters, in the last decade, proteoliposomes obtained with optimized methodologies have been used for studying plasma membrane transporters and defining their functional and kinetic properties and structure/function relationships. A lot of information has been obtained which has clarified and completed the knowledge on several transporters among which the OCTN sub-family members, transporters for neutral amino acid, B0AT1 and ASCT2, and others. Transporters can mediate absorption of substrate-like derivatives or drugs, improving their bioavailability or can interact with these compounds or other xenobiotics, leading to side/toxic effects. Therefore, proteoliposomes have recently been used for studying the interaction of some plasma membrane and mitochondrial transporters with toxic compounds, such as mercurials, H2O2 and some drugs. Several mechanisms have been defined and in some cases the amino acid residues responsible for the interaction have been identified. The data obtained indicate proteoliposomes as a novel and potentially important tool in drug discovery.
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12
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Karpowicz RJ, Dunn M, Sulzer D, Sames D. APP+, a fluorescent analogue of the neurotoxin MPP+, is a marker of catecholamine neurons in brain tissue, but not a fluorescent false neurotransmitter. ACS Chem Neurosci 2013; 4:858-69. [PMID: 23647019 PMCID: PMC3656749 DOI: 10.1021/cn400038u] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 04/21/2013] [Indexed: 01/20/2023] Open
Abstract
We have previously introduced fluorescent false neurotransmitters (FFNs) as optical reporters that enable visualization of individual dopaminergic presynaptic terminals and their activity in the brain. In this context, we examined the fluorescent pyridinium dye 4-(4-dimethylamino)phenyl-1-methylpyridinium (APP+), a fluorescent analogue of the dopaminergic neurotoxin MPP+, in acute mouse brain tissue. APP+ is a substrate for the dopamine transporter (DAT), norepinephrine transporter (NET), and serotonin transporter (SERT), and as such represented a candidate for the development of new FFN probes. Here we report that APP+ labels cell bodies of catecholaminergic neurons in the midbrain in a DAT- and NET-dependent manner, as well as fine dopaminergic axonal processes in the dorsal striatum. APP+ destaining from presynaptic terminals in the dorsal striatum was also examined under the conditions inducing depolarization and exocytotic neurotransmitter release. Application of KCl led to a small but significant degree of destaining (approximately 15% compared to control), which stands in contrast to a nearly complete destaining of the new generation FFN agent, FFN102. Electrical stimulation of brain slices at 10 Hz afforded no significant change in the APP+ signal. These results indicate that the majority of the APP+ signal in axonal processes originates from labeled organelles including mitochondria, whereas only a minor component of the APP+ signal represents the releasable synaptic vesicular pool. These results also show that APP+ may serve as a useful probe for identifying catecholaminergic innervations in the brain, although it is a poor candidate for the development of FFNs.
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Affiliation(s)
- Richard J. Karpowicz
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York
10027, United States
| | - Matthew Dunn
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York
10027, United States
| | - David Sulzer
- Departments
of Neurology, Psychiatry and Pharmacology, Columbia University
Medical Center, New York, New York 10032, United States
- Department of Neuroscience, New York Psychiatric Institute, New York, New York
10032, United States
| | - Dalibor Sames
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York
10027, United States
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13
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Yaffe D, Radestock S, Shuster Y, Forrest LR, Schuldiner S. Identification of molecular hinge points mediating alternating access in the vesicular monoamine transporter VMAT2. Proc Natl Acad Sci U S A 2013; 110:E1332-41. [PMID: 23530208 PMCID: PMC3625309 DOI: 10.1073/pnas.1220497110] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Vesicular monoamine transporter 2 (VMAT2) catalyzes transport of monoamines into storage vesicles in a process that involves exchange of the charged monoamine with two protons. VMAT2 is a member of the DHA12 family of multidrug transporters that belongs to the major facilitator superfamily (MFS) of secondary transporters. Here we present a homology model of VMAT2, which has the standard MFS fold, that is, with two domains of six transmembrane helices each which are related by twofold pseudosymmetry and whose axis runs normal to the membrane and between the two halves. Demonstration of the essential role of a membrane-embedded glutamate and confirmation of the existence of a hydrogen bond probably involved in proton transport provide experimental evidence that validates some of the predictions inherent to the model. Moreover, we show the essential role of residues at two anchor points between the two bundles. These residues appear to function as molecular hinge points about which the two six transmembrane-helix bundles flex and straighten to open and close the pathways on either side of the membrane as required for transport. Polar residues that create a hydrogen bond cluster form one of the anchor points of VMAT2. The other results from hydrophobic interactions. Residues at the anchor points are strongly conserved in other MFS transporters in one way or another, suggesting that interactions at these locations will be critical in most, if not all, MFS transporters.
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Affiliation(s)
- Dana Yaffe
- Department of Biological Chemistry, Alexander A. Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel; and
| | - Sebastian Radestock
- Computational Structural Biology Group, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Yonatan Shuster
- Department of Biological Chemistry, Alexander A. Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel; and
| | - Lucy R. Forrest
- Computational Structural Biology Group, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Shimon Schuldiner
- Department of Biological Chemistry, Alexander A. Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel; and
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14
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Jaehme M, Michel H. Evaluation of cell-free protein synthesis for the crystallization of membrane proteins--a case study on a member of the glutamate transporter family from Staphylothermus marinus. FEBS J 2013; 280:1112-25. [PMID: 23279902 DOI: 10.1111/febs.12105] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 12/07/2012] [Accepted: 12/18/2012] [Indexed: 12/25/2022]
Abstract
Cell-free in vitro synthesis of proteins using coupled transcription/translation is considered to be a powerful alternative to the use of traditional cell-based expression systems. Recently, promising developments have been reported applying cell-free production to membrane proteins for structural biology and in particular for NMR spectroscopy. However, the general applicability of this system to produce large amounts of stable, functional and homogeneous membrane proteins as required for X-ray crystallography remains to be determined. Here, we present a systematic study comparing structural and functional properties of membrane proteins produced using Escherichia coli derived in vitro and in vivo expression systems. The function of the target membrane protein, a previously uncharacterized bacterial glutamate transporter homolog from Staphylothermus marinus, was analyzed using ligand binding and transport assays. In addition, the protein structure was investigated with respect to its overall fold and oligomeric state in different detergents. We found that the protein synthesized in vitro is highly stable and monodisperse. However, in contrast to the protein produced using an in vivo system, it was not able to assemble into the native trimeric state nor to bind substrate. We thus conclude that cell-free expression systems can compromise folding and function of such complex secondary active transporters. The expression product has to be carefully characterized prior to biophysical investigations like crystallography of membrane proteins.
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Affiliation(s)
- Michael Jaehme
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
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15
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Kang CK, Liu FC, Chang WB, Lee TH. Effects of low environmental salinity on the cellular profiles and expression of Na+, K+-ATPase and Na+, K+, 2Cl- cotransporter 1 of branchial mitochondrion-rich cells in the juvenile marine fish Monodactylus argenteus. FISH PHYSIOLOGY AND BIOCHEMISTRY 2012; 38:665-678. [PMID: 21863333 DOI: 10.1007/s10695-011-9549-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 08/06/2011] [Indexed: 05/31/2023]
Abstract
The goal of this study was to determine the osmoregulatory ability of a juvenile marine fish, silver moony (Monodactylus argenteus), for the purpose of developing a new experimental species for ecophysiological research. In this study, M. argenteus was acclimated to freshwater (FW), brackish water (BW), or seawater (SW). The salinity tolerance of this euryhaline species was effective, and the fish survived well upon osmotic challenges. The largest apical surface of mitochondrion-rich cells was found in the FW individuals. Immunohistochemical staining revealed that Na(+), K(+)-ATPase immunoreactive (NKA-IR) cells were distributed in the interlamellar region of the gill filaments of the silver moony in all experimental groups. In addition to the filaments, NKA-IR cells were also found in the lamellae of the FW individuals. The number of NKA-IR cells in the gills of the FW individuals exceeded that of the BW and SW individuals. The NKA-IR cells of FW and SW individuals exhibited bigger size than that of BW fish. The NKA activities and protein expression of the NKA α-subunit in the gills of the FW individuals were significantly higher than in the BW and SW groups. Additionally, the relative amounts of Na(+), K(+), 2Cl(-) cotransporter 1 (NKCC1) were salinity-dependent in the gills. Immunofluorescent signals of NKCC1 were localized to the basolateral membrane of NKA-IR cells in all groups. In the gills of the FW individuals, however, some NKA-IR cells did not exhibit a basolateral NKCC1 signal. In conclusion, the present study illustrated the osmoregulatory mechanisms of this easy- and economic-to-rear marine teleost with euryhaline capacity and proved the silver moony to be a good experimental animal.
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Affiliation(s)
- Chao-Kai Kang
- Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan
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16
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Overexpression of VMAT-2 and DT-diaphorase protects substantia nigra-derived cells against aminochrome neurotoxicity. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1125-36. [PMID: 22483869 DOI: 10.1016/j.bbadis.2012.03.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 03/16/2012] [Accepted: 03/20/2012] [Indexed: 12/31/2022]
Abstract
We tested the hypothesis that both VMAT-2 and DT-diaphorase are an important cellular defense against aminochrome-dependent neurotoxicity during dopamine oxidation. A cell line with VMAT-2 and DT-diaphorase over-expressed was created. The transfection of RCSN-3 cells with a bicistronic plasmid coding for VMAT-2 fused with GFP-IRES-DT-diaphorase cDNA induced a significant increase in protein expression of VMAT-2 (7-fold; P<0.001) and DT-diaphorase (9-fold; P<0.001), accompanied by a 4- and 5.5-fold significant increase in transport and enzyme activity, respectively. Studies with synaptic vesicles from rat substantia nigra revealed that VMAT-2 uptake of ³H-aminochrome 6.3 ± 0.4nmol/min/mg was similar to dopamine uptake 6.2 ± 0.3nmol/min/mg that which were dependent on ATP. Interestingly, aminochrome uptake was inhibited by 2μM lobeline but not reserpine (1 and 10μM). Incubation of cells overexpressing VMAT-2 and DT-diaphorase with 20μM aminochrome resulted in (i) a significant decrease in cell death (6-fold, P<0.001); (ii) normal ultra structure determined by transmission electron microscopy contrasting with a significant increase of autophagosome and a dramatic remodeling of the mitochondrial inner membrane in wild type cells; (iii) normal level of ATP (256 ± 11μM) contrasting with a significant decrease in wild type cells (121±11μM, P<0.001); and (iv) a significant decrease in DNA laddering (21 ± 8pixels, P<0.001) cells in comparison with wild type cells treated with 20μM aminochrome (269 ± 9). These results support our hypothesis that VMAT-2 and DT-diaphorase are an important defense system against aminochrome formed during dopamine oxidation.
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17
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Yang WK, Kang CK, Chen TY, Chang WB, Lee TH. Salinity-dependent expression of the branchial Na+/K+/2Cl− cotransporter and Na+/K+-ATPase in the sailfin molly correlates with hypoosmoregulatory endurance. J Comp Physiol B 2011; 181:953-64. [PMID: 21445564 DOI: 10.1007/s00360-011-0568-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 03/07/2011] [Accepted: 03/09/2011] [Indexed: 10/18/2022]
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18
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Navailles S, De Deurwaerdère P. Presynaptic control of serotonin on striatal dopamine function. Psychopharmacology (Berl) 2011; 213:213-42. [PMID: 20953589 DOI: 10.1007/s00213-010-2029-y] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 09/14/2010] [Indexed: 11/27/2022]
Abstract
RATIONALE The influences of the serotonergic system on dopamine (DA) neuron activity have received considerable attention during the last three decades due to the real opportunity to improve disorders related to central DA neuron dysfunctions such as Parkinson's disease, schizophrenia, or drug abuse with serotonergic drugs. Numerous biochemical and behavioral data indicate that serotonin (5-HT) affects dopaminergic terminal function in the striatum. OBJECTIVE The authors propose a thorough examination of data showing controversial effects induced by striatal 5-HT on dopaminergic activity. RESULTS Inhibitory and excitatory effects of exogenous 5-HT have been reported on DA release and synthesis, involving various striatal 5-HT receptors. 5-HT also promotes an efflux of DA through reversal of the direction of DA transport. By analogy with the mechanism of action described for amphetamine, the consequences of 5-HT entering DA terminals might explain both the excitatory and inhibitory effects of 5-HT on presynaptic DA terminal activity, but the physiological relevance of this mechanism is far from clear. The recent data suggest that the endogenous 5-HT system affects striatal DA release in a state-dependent manner associated with the conditional involvement of various 5-HT receptors such as 5-HT(2A), 5-HT(2C), 5-HT(3), and 5-HT(4) receptors. CONCLUSION Methodological and pharmacological issues have prevented a comprehensive overview of the influence of 5-HT on striatal DA activity. The distribution of striatal 5-HT receptors and their restricted influence on DA neuron activity suggest that the endogenous 5-HT system exerts multiple and subtle influences on DA-mediated behaviors.
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Affiliation(s)
- Sylvia Navailles
- Unité Mixte de Recherche Centre National de la Recherche Scientifique 5227, Université Victor Segalen Bordeaux 2, Bordeaux, France
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19
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Elbaz Y, Danieli T, Kanner BI, Schuldiner S. Expression of neurotransmitter transporters for structural and biochemical studies. Protein Expr Purif 2010; 73:152-60. [PMID: 20566324 DOI: 10.1016/j.pep.2010.06.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 05/12/2010] [Accepted: 06/01/2010] [Indexed: 11/27/2022]
Abstract
Neurotransmitter transporters play essential roles in the process of neurotransmission. Vesicular neurotransmitter transporters mediate storage inside secretory vesicles in a process that involves the exchange of lumenal H(+) for cytoplasmic transmitter. Retrieval of the neurotransmitter from the synaptic cleft catalyzed by sodium-coupled transporters is critical for the termination of the synaptic actions of the released neurotransmitter. Our current understanding of the mechanism of these transporters is based on functional and biochemical characterization but is lacking high-resolution structural information. Very few structures of membrane transport systems from mammalian origin have been solved to atomic resolution, mainly because of the difficulty in obtaining large amounts of purified protein. Development of high yield heterologous expression systems suitable for mammalian neurotransmitter transporters is essential to enable the production of purified protein for structural studies. Such a system makes possible also the production of mutants that can be used in biochemical and biophysical studies. We describe here a screen for the expression of the vesicular monoamine transporter 2 (VMAT2) in cell-free and baculovirus expression systems and discuss the expression of VMAT2 in other systems as well (bacterial, yeast and mammalian cell lines). After screening and optimization, we achieved high yield (2-2.5 mg/l) expression of functional VMAT2 in insect cells. The system was also used for the expression of three additional plasma membrane neurotransmitter transporters. All were functional and expressed to high levels. Our results demonstrate the advantages of the baculovirus expression system for the expression of mammalian neurotransmitter transporters in a functional state.
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Affiliation(s)
- Yael Elbaz
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
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20
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Tang CH, Wu WY, Tsai SC, Yoshinaga T, Lee TH. Elevated Na+/K+-ATPase responses and its potential role in triggering ion reabsorption in kidneys for homeostasis of marine euryhaline milkfish (Chanos chanos) when acclimated to hypotonic fresh water. J Comp Physiol B 2010; 180:813-24. [PMID: 20232202 DOI: 10.1007/s00360-010-0458-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 12/17/2009] [Accepted: 02/17/2010] [Indexed: 11/25/2022]
Affiliation(s)
- Cheng-Hao Tang
- Department of Life Sciences, National Chung-Hsing University, Taichung, 402, Taiwan
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21
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An improved radiosynthesis of [18F]AV-133: a PET imaging agent for vesicular monoamine transporter 2. Nucl Med Biol 2010; 37:133-41. [DOI: 10.1016/j.nucmedbio.2009.10.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 10/23/2009] [Accepted: 10/26/2009] [Indexed: 11/23/2022]
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22
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Gros Y, Schuldiner S. Directed evolution reveals hidden properties of VMAT, a neurotransmitter transporter. J Biol Chem 2009; 285:5076-84. [PMID: 20007701 DOI: 10.1074/jbc.m109.081216] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The vesicular neurotransmitter transporter VMAT2 is responsible for the transport of monoamines into synaptic and storage vesicles. VMAT2 is the target of many psychoactive drugs and is essential for proper neurotransmission and survival. Here we describe a new expression system in Saccharomyces cerevisiae that takes advantage of the polyspecificity of VMAT2. Expression of rVMAT2 confers resistance to acriflavine and to the parkinsonian toxin 1-methyl-4-phenylpyridinium (MPP(+)) by their removal into the yeast vacuole. This expression system allowed identification of a new substrate, acriflavine, and isolation of mutants with modified affinity to tetrabenazine (TBZ), a non-competitive inhibitor of VMAT2 that is used in the treatment of various movement disorders including Tourette syndrome and Huntington chorea. Whereas one type of mutant obtained displayed decreased affinity to TBZ, a second type showed only a slight decrease in the affinity to TBZ, displayed a higher K(m) to the neurotransmitter serotonin, but conferred increased resistance to acriflavine and MPP(+). A protein where both types of mutations were combined (with only three amino acid replacements) lost most of the properties of the neurotransmitter transporter (TBZ-insensitive, no transport of neurotransmitter) but displayed enhanced resistance to the above toxicants. The work described here shows that in the case of rVMAT2, loss of traits acquired in evolution of function (such as serotonin transport and TBZ binding) bring about an improvement in older functions such as resistance to toxic compounds. A process that has taken millions of years of evolution can be reversed by three mutations.
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Affiliation(s)
- Yael Gros
- Department of Biological Chemistry, Alexander A. Silberman Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel
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23
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Song Z, Ultenius C, Meyerson BA, Linderoth B. Pain relief by spinal cord stimulation involves serotonergic mechanisms: An experimental study in a rat model of mononeuropathy. Pain 2009; 147:241-8. [DOI: 10.1016/j.pain.2009.09.020] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 09/15/2009] [Accepted: 09/18/2009] [Indexed: 01/03/2023]
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24
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Tipsmark CK, Kiilerich P, Nilsen TO, Ebbesson LOE, Stefansson SO, Madsen SS. Branchial expression patterns of claudin isoforms in Atlantic salmon during seawater acclimation and smoltification. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1563-74. [PMID: 18321951 DOI: 10.1152/ajpregu.00915.2007] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In euryhaline teleosts, permeability changes in gill epithelia are essential during acclimation to changed salinity. This study examined expression patterns of branchial tight junction proteins called claudins, which are important determinants of ion selectivity and general permeability in epithelia. We identified Atlantic salmon genes belonging to the claudin family by screening expressed sequence tag libraries available at NCBI, and classification was performed with the aid of maximum likelihood analysis. In gill libraries, five isoforms (10e, 27a, 28a, 28b, and 30) were present, and quantitative PCR analysis confirmed tissue-specific expression in gill when compared with kidney, intestine, heart, muscle, brain, and liver. Expression patterns during acclimation of freshwater salmon to seawater (SW) and during the smoltification process were examined. Acclimation to SW reduced the expression of claudin 27a and claudin 30 but had no overall effect on claudin 28a and claudin 28b. In contrast, SW induced a fourfold increase in expression of claudin 10e. In accord, a peak in branchial claudin 10e was observed during smoltification in May, coinciding with optimal SW tolerance. Smoltification induced no significant changes in expression of the other isoforms. This study demonstrates the expression of an array of salmon claudin isoforms and shows that SW acclimation involves inverse regulation, in the gill, of claudin 10e vs. claudin 27a and 30. It is possible that claudin 10e is an important component of cation selective channels, whereas reduction in claudin 27a and 30 may change permeability conditions in favor of the ion secretory mode of the SW gill.
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Affiliation(s)
- C K Tipsmark
- Institute of Biology, University of Southern Denmark, Odense, Denmark.
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