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Dunham KE, Khaled KH, Weizman L, Venton BJ. Microdosing ketamine in Drosophila does not block serotonin reuptake, but causes complex behavioral changes mediated by glutamate and serotonin receptors. J Neurochem 2024; 168:1097-1112. [PMID: 38323657 PMCID: PMC11136605 DOI: 10.1111/jnc.16070] [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: 07/07/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 02/08/2024]
Abstract
Microdosing ketamine is a novel antidepressant for treatment-resistant depression. Traditional antidepressants, like selective serotonin reuptake inhibitors (SSRIs), inhibit serotonin reuptake, but it is not clear if ketamine shows a similar mechanism. Here, we tested the effects of feeding ketamine and SSRIs to Drosophila melanogaster larvae, which has a similar serotonin system to mammals and is a good model to track depressive behaviors, such as locomotion and feeding. Fast-scan cyclic voltammetry (FSCV) was used to measure optogenetically stimulated serotonin changes, and locomotion tracking software and blue dye feeding to monitor behavior. We fed larvae various doses (1-100 mM) of antidepressants for 24 h and found that 1 mM ketamine did not affect serotonin, but increased locomotion and feeding. Low doses (≤10 mM) of escitalopram and fluoxetine inhibited dSERT and also increased feeding and locomotion behaviors. At 100 mM, ketamine inhibited dSERT and increased serotonin concentrations, but decreased locomotion and feeding because of its anesthetic properties. Since microdosing ketamine causes behavioral effects, we further investigated behavioral changes with a SERT16 mutant and low doses of other NMDA receptor antagonists and 5-HT1A and 2 agonists. Feeding and locomotion changes were similar to ketamine in the mutant, and we found NMDA receptor antagonism increased feeding, while serotonin receptor agonism increased locomotion, which could explain these effects with ketamine. Ultimately, this work shows that Drosophila is a good model to discern antidepressant mechanisms, and that ketamine does not work on dSERT like SSRIs, but effects behavior with other mechanisms that should be investigated further.
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Affiliation(s)
- Kelly E Dunham
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, USA
| | - Kani H Khaled
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, USA
| | - Leah Weizman
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, USA
| | - B Jill Venton
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, USA
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2
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Dunham KE, Venton BJ. Electrochemical and biosensor techniques to monitor neurotransmitter changes with depression. Anal Bioanal Chem 2024; 416:2301-2318. [PMID: 38289354 PMCID: PMC10950978 DOI: 10.1007/s00216-024-05136-9] [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: 11/09/2023] [Revised: 12/29/2023] [Accepted: 01/09/2024] [Indexed: 03/21/2024]
Abstract
Depression is a common mental illness. However, its current treatments, like selective serotonin reuptake inhibitors (SSRIs) and micro-dosing ketamine, are extremely variable between patients and not well understood. Three neurotransmitters: serotonin, histamine, and glutamate, have been proposed to be key mediators of depression. This review focuses on analytical methods to quantify these neurotransmitters to better understand neurological mechanisms of depression and how they are altered during treatment. To quantitatively measure serotonin and histamine, electrochemical techniques such as chronoamperometry and fast-scan cyclic voltammetry (FSCV) have been improved to study how specific molecular targets, like transporters and receptors, change with antidepressants and inflammation. Specifically, these studies show that different SSRIs have unique effects on serotonin reuptake and release. Histamine is normally elevated during stress, and a new inflammation hypothesis of depression links histamine and cytokine release. Electrochemical measurements revealed that stress increases histamine, decreases serotonin, and leads to changes in cytokines, like interleukin-6. Biosensors can also measure non-electroactive neurotransmitters, including glutamate and cytokines. In particular, new genetic sensors have shown how glutamate changes with chronic stress, as well as with ketamine treatment. These techniques have been used to characterize how ketamine changes glutamate and serotonin, and to understand how it is different from SSRIs. This review briefly outlines how these electrochemical techniques work, but primarily highlights how they have been used to understand the mechanisms of depression. Future studies should explore multiplexing techniques and personalized medicine using biomarkers in order to investigate multi-analyte changes to antidepressants.
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Affiliation(s)
- Kelly E Dunham
- Department of Chemistry, University of Virginia, Charlottesville, VA, 22904, USA
| | - B Jill Venton
- Department of Chemistry, University of Virginia, Charlottesville, VA, 22904, USA.
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3
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Dunham KE, Khaled KH, Weizman L, Venton BJ. Microdosing ketamine in Drosophila does not inhibit SERT like SSRIs, but causes behavioral changes mediated by glutamate and serotonin receptors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.07.566121. [PMID: 37986873 PMCID: PMC10659355 DOI: 10.1101/2023.11.07.566121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Recently, the FDA approved microdosing ketamine for treatment resistant depression. Traditional antidepressants, like serotonin selective reuptake inhibitors (SSRIs), block serotonin reuptake, but it is not clear if ketamine blocks serotonin reuptake. Here, we tested the effects of feeding ketamine and SSRIs to Drosophila melanogaster larvae, which has a similar serotonin system to mammals, and is a good model to track depression behaviors, such as locomotion and feeding. Fast-scan cyclic voltammetry (FSCV) was used to measure optogenetically-stimulated serotonin changes, and locomotion tracking software and blue dye feeding to monitor behavior. We fed larvae various doses (1-100 mM) of antidepressants for 24 hours and found that 1 mM ketamine did not affect serotonin, but increased locomotion and feeding. Low doses (≤ 10 mM) of escitalopram and fluoxetine inhibited dSERT and also increased feeding and locomotion behaviors. At 100 mM, ketamine inhibited dSERT and increased serotonin concentrations, but decreased locomotion and feeding due to its anesthetic properties. Since microdosing ketamine causes behavioral effects, we also investigated behavior changes with low doses of other NMDA receptor antagonists and 5-HT1A and 2 agonists, which are other possible sites for ketamine action. NMDA receptor antagonism increased feeding, while serotonin receptor agonism increased locomotion, which could explain these effects with ketamine. Ultimately, this work shows that Drosophila is a good model to discern antidepressant mechanisms, and that ketamine does not work on dSERT like SSRIs at microdoses, but affects behavior with other mechanisms.
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Affiliation(s)
- Kelly E Dunham
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, 22904, USA
| | - Kani H Khaled
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, 22904, USA
| | - Leah Weizman
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, 22904, USA
| | - B Jill Venton
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, 22904, USA
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4
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Miller SJ, Darji RY, Walaieh S, Lewis JA, Logan R. Senolytic and senomorphic secondary metabolites as therapeutic agents in Drosophila melanogaster models of Parkinson's disease. Front Neurol 2023; 14:1271941. [PMID: 37840914 PMCID: PMC10568035 DOI: 10.3389/fneur.2023.1271941] [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: 08/04/2023] [Accepted: 09/04/2023] [Indexed: 10/17/2023] Open
Abstract
Drosophila melanogaster is a valuable model organism for a wide range of biological exploration. The well-known advantages of D. melanogaster include its relatively simple biology, the ease with which it is genetically modified, the relatively low financial and time costs associated with their short gestation and life cycles, and the large number of offspring they produce per generation. D. melanogaster has facilitated the discovery of many significant insights into the pathology of Parkinson's disease (PD) and has served as an excellent preclinical model of PD-related therapeutic discovery. In this review, we provide an overview of the major D. melanogaster models of PD, each of which provide unique insights into PD-relevant pathology and therapeutic targets. These models are discussed in the context of their past, current, and future potential use for studying the utility of secondary metabolites as therapeutic agents in PD. Over the last decade, senolytics have garnered an exponential interest in their ability to mitigate a broad spectrum of diseases, including PD. Therefore, an emphasis is placed on the senolytic and senomorphic properties of secondary metabolites. It is expected that D. melanogaster will continue to be critical in the effort to understand and improve treatment of PD, including their involvement in translational studies focused on secondary metabolites.
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Affiliation(s)
- Sean J. Miller
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT, United States
| | - Rayyan Y. Darji
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT, United States
| | - Sami Walaieh
- Department of Biology, Eastern Nazarene College, Quincy, MA, United States
| | - Jhemerial A. Lewis
- Department of Biology, Eastern Nazarene College, Quincy, MA, United States
| | - Robert Logan
- Department of Biology, Eastern Nazarene College, Quincy, MA, United States
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5
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Rosikon KD, Bone MC, Lawal HO. Regulation and modulation of biogenic amine neurotransmission in Drosophila and Caenorhabditis elegans. Front Physiol 2023; 14:970405. [PMID: 36875033 PMCID: PMC9978017 DOI: 10.3389/fphys.2023.970405] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 01/23/2023] [Indexed: 02/18/2023] Open
Abstract
Neurotransmitters are crucial for the relay of signals between neurons and their target. Monoamine neurotransmitters dopamine (DA), serotonin (5-HT), and histamine are found in both invertebrates and mammals and are known to control key physiological aspects in health and disease. Others, such as octopamine (OA) and tyramine (TA), are abundant in invertebrates. TA is expressed in both Caenorhabditis elegans and Drosophila melanogaster and plays important roles in the regulation of essential life functions in each organism. OA and TA are thought to act as the mammalian homologs of epinephrine and norepinephrine respectively, and when triggered, they act in response to the various stressors in the fight-or-flight response. 5-HT regulates a wide range of behaviors in C. elegans including egg-laying, male mating, locomotion, and pharyngeal pumping. 5-HT acts predominantly through its receptors, of which various classes have been described in both flies and worms. The adult brain of Drosophila is composed of approximately 80 serotonergic neurons, which are involved in modulation of circadian rhythm, feeding, aggression, and long-term memory formation. DA is a major monoamine neurotransmitter that mediates a variety of critical organismal functions and is essential for synaptic transmission in invertebrates as it is in mammals, in which it is also a precursor for the synthesis of adrenaline and noradrenaline. In C. elegans and Drosophila as in mammals, DA receptors play critical roles and are generally grouped into two classes, D1-like and D2-like based on their predicted coupling to downstream G proteins. Drosophila uses histamine as a neurotransmitter in photoreceptors as well as a small number of neurons in the CNS. C. elegans does not use histamine as a neurotransmitter. Here, we review the comprehensive set of known amine neurotransmitters found in invertebrates, and discuss their biological and modulatory functions using the vast literature on both Drosophila and C. elegans. We also suggest the potential interactions between aminergic neurotransmitters systems in the modulation of neurophysiological activity and behavior.
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Affiliation(s)
- Katarzyna D Rosikon
- Neuroscience Program, Department of Biological Sciences, Delaware State University, Dover, DE, United States
| | - Megan C Bone
- Neuroscience Program, Department of Biological Sciences, Delaware State University, Dover, DE, United States
| | - Hakeem O Lawal
- Neuroscience Program, Department of Biological Sciences, Delaware State University, Dover, DE, United States
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6
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Bernardt TM, Treviso EM, Cancian M, Silva MDM, da Rocha JBT, Loreto ELS. Chemotherapy Drugs Act Differently in the Expression and Somatic Mobilization of the mariner Transposable Element in Drosophila simulans. Genes (Basel) 2022; 13:genes13122374. [PMID: 36553641 PMCID: PMC9777735 DOI: 10.3390/genes13122374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/10/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Transposable elements (TEs) are abundant in genomes. Their mobilization can lead to genetic variability that is useful for evolution, but can also have deleterious biological effects. Somatic mobilization (SM) has been linked to degenerative diseases, such as Alzheimer's disease and cancer. We used a Drosophila simulans strain, in which SM can be measured by counting red spots in the eyes, to investigate how chemotherapeutic agents affect expression and SM of the mariner TE. Flies were treated with Cisplatin, Dacarbazine, and Daunorubicin. After acute exposure, relative expression of mariner was quantified by RT-qPCR and oxidative stress was measured by biochemical assays. Exposure to 50 and 100 µg/mL Cisplatin increased mariner expression and ROS levels; catalase activity increased at 100 µg/mL. With chronic exposure, the number of spots also increased, indicating higher mariner SM. Dacarbazine (50 and 100 µg/mL) did not significantly alter mariner expression or mobilization or ROS levels, but decreased catalase activity (100 µg/mL). Daunorubicin (25 and 50 µM) increased mariner expression, but decreased mariner SM. ROS and catalase activity were also reduced. Our data suggest that stress factors may differentially affect the expression and SM of TEs. The increase in mariner transposase gene expression is necessary, but not sufficient for mariner SM.
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Affiliation(s)
- Taís Maus Bernardt
- Biological Sciences, Federal University of Santa Maria (UFSM), Santa Maria 97105-000, RS, Brazil
| | - Estéfani Maria Treviso
- Biological Sciences, Federal University of Santa Maria (UFSM), Santa Maria 97105-000, RS, Brazil
| | - Mariana Cancian
- Genetic and Molecular Biology, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre 91501-970, RS, Brazil
| | - Monica de Medeiros Silva
- Department of Biochemistry and Molecular Biology, Federal University of Santa Maria (UFSM), Av. Roraima 1000, Camobi, Santa Maria 97105-900, RS, Brazil
| | - João Batista Teixeira da Rocha
- Department of Biochemistry and Molecular Biology, Federal University of Santa Maria (UFSM), Av. Roraima 1000, Camobi, Santa Maria 97105-900, RS, Brazil
| | - Elgion Lucio Silva Loreto
- Department of Biochemistry and Molecular Biology, Federal University of Santa Maria (UFSM), Av. Roraima 1000, Camobi, Santa Maria 97105-900, RS, Brazil
- Correspondence:
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7
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Dunham KE, Venton BJ. SSRI antidepressants differentially modulate serotonin reuptake and release in Drosophila. J Neurochem 2022; 162:404-416. [PMID: 35736504 PMCID: PMC9427694 DOI: 10.1111/jnc.15658] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/27/2022] [Accepted: 06/17/2022] [Indexed: 11/26/2022]
Abstract
Selective serotonin reuptake inhibitor (SSRI) antidepressants are commonly prescribed treatments for depression, but their effects on serotonin reuptake and release are not well understood. Drosophila melanogaster, the fruit fly, expresses the serotonin transporter (dSERT), the major target of SSRIs, but real-time serotonin changes after SSRIs have not been characterized in this model. The goal of this study was to characterize effects of SSRIs on serotonin concentration and reuptake in Drosophila larvae. We applied various doses (0.1-100 μM) of fluoxetine (Prozac), escitalopram (Lexapro), citalopram (Celexa), and paroxetine (Paxil), to ventral nerve cord (VNC) tissue and measured optogenetically-stimulated serotonin release with fast-scan cyclic voltammetry (FSCV). Fluoxetine increased reuptake from 1 to 100 μM, but serotonin concentration only increased at 100 μM. Thus, fluoxetine occupies dSERT and slows clearance but does not affect concentration. Escitalopram and paroxetine increased serotonin concentrations at all doses, but escitalopram increased reuptake more. Citalopram showed lower concentration changes and faster reuptake profiles compared with escitalopram, so the racemic mixture of citalopram does not change reuptake as much as the S-isomer. Dose response curves were constructed to compare dSERT affinities and paroxetine showed the highest affinity and fluoxetine the lowest. These data demonstrate SSRI mechanisms are complex, with separate effects on reuptake or release. Furthermore, dynamic serotonin changes in Drosophila are similar to previous studies in mammals. This work establishes how antidepressants affect serotonin in real-time, which is useful for future studies that will investigate pharmacological effects of SSRIs with different genetic mutations in Drosophila.
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Affiliation(s)
- Kelly E Dunham
- Department of Chemistry, University of Virginia, Virginia, USA
| | - B Jill Venton
- Department of Chemistry, University of Virginia, Virginia, USA
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8
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A pair of dopamine neurons mediate chronic stress signals to induce learning deficit in Drosophila melanogaster. Proc Natl Acad Sci U S A 2021; 118:2023674118. [PMID: 34654742 DOI: 10.1073/pnas.2023674118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2021] [Indexed: 11/18/2022] Open
Abstract
Chronic stress could induce severe cognitive impairments. Despite extensive investigations in mammalian models, the underlying mechanisms remain obscure. Here, we show that chronic stress could induce dramatic learning and memory deficits in Drosophila melanogaster The chronic stress-induced learning deficit (CSLD) is long lasting and associated with other depression-like behaviors. We demonstrated that excessive dopaminergic activity provokes susceptibility to CSLD. Remarkably, a pair of PPL1-γ1pedc dopaminergic neurons that project to the mushroom body (MB) γ1pedc compartment play a key role in regulating susceptibility to CSLD so that stress-induced PPL1-γ1pedc hyperactivity facilitates the development of CSLD. Consistently, the mushroom body output neurons (MBON) of the γ1pedc compartment, MBON-γ1pedc>α/β neurons, are important for modulating susceptibility to CSLD. Imaging studies showed that dopaminergic activity is necessary to provoke the development of chronic stress-induced maladaptations in the MB network. Together, our data support that PPL1-γ1pedc mediates chronic stress signals to drive allostatic maladaptations in the MB network that lead to CSLD.
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9
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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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10
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Vesicular neurotransmitter transporters in Drosophila melanogaster. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183308. [PMID: 32305263 DOI: 10.1016/j.bbamem.2020.183308] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/09/2020] [Accepted: 04/10/2020] [Indexed: 12/11/2022]
Abstract
Drosophila melanogaster express vesicular transporters for the storage of neurotransmitters acetylcholine, biogenic amines, GABA, and glutamate. The large array of powerful molecular-genetic tools available in Drosophila enhances the use of this model organism for studying transporter function and regulation.
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11
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Overexpression of the vesicular acetylcholine transporter disrupts cognitive performance and causes age-dependent locomotion decline in Drosophila. Mol Cell Neurosci 2020; 105:103483. [PMID: 32217162 DOI: 10.1016/j.mcn.2020.103483] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 03/14/2020] [Accepted: 03/22/2020] [Indexed: 12/11/2022] Open
Abstract
Acetylcholinergic (ACh) neurotransmission is essential for key organismal functions such as locomotion and cognition. However, the mechanism through which ACh is regulated in the central nervous system is not fully understood. The vesicular acetylcholine transporter (VAChT) mediates the packaging and transport of ACh for exocytotic release and is a critical component of the ACh release machinery. Yet its precise role in the maintenance of cholinergic tone remains a subject of active investigation. Here we use the overexpression of VAChT as a tool to investigate the role of changes in ACh exocytosis on the regulation of synaptic activity and its downstream consequences. We measured the effect of an increase in VAChT expression on locomotion and cognitive performance as well as on organismal survival across the lifespan. We report the surprising finding that increased VAChT expression results in a significantly shorter lifespan in comparison to control flies. Moreover, constructs overexpressing VAChT demonstrate an age-dependent decrease in locomotion performance. Importantly, we report clear deficits in learning and memory which we measured through a courtship conditioning assay. Together, these data provide evidence for the adverse effects of overexpression of the vesicular acetylcholine transporter in the maintenance of normal behavioral abilities in Drosophila and demonstrates for the first time a role for ACh in the regulation of organismal survival.
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12
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Brown DG, Wobst HJ. Opportunities and Challenges in Phenotypic Screening for Neurodegenerative Disease Research. J Med Chem 2019; 63:1823-1840. [PMID: 31268707 DOI: 10.1021/acs.jmedchem.9b00797] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Toxic misfolded proteins potentially underly many neurodegenerative diseases, but individual targets which regulate these proteins and their downstream detrimental effects are often unknown. Phenotypic screening is an unbiased method to screen for novel targets and therapeutic molecules and span the range from primitive model organisms such as Sacchaomyces cerevisiae, which allow for high-throughput screening to patient-derived cell-lines that have a close connection to the disease biology but are limited in screening capacity. This perspective will review current phenotypic models, as well as the chemical screening strategies most often employed. Advances in in 3D cell cultures, high-content screens, robotic microscopy, CRISPR screening, and use of machine learning methods to process the enormous amount of data generated by these screens are certain to change the paradigm for phenotypic screening and will be discussed.
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Affiliation(s)
- Dean G Brown
- Hit Discovery, Discovery Sciences, BioPharmaceuticals R&D, AstraZeneca, 35 Gatehouse Drive, Waltham, Massachusetts 02451, United States
| | - Heike J Wobst
- Neuroscience, BioPharmaceuticals R&D, AstraZeneca, 35 Gatehouse Drive, Waltham, Massachusetts 02451, United States
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13
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Monnier V, Llorens JV, Navarro JA. Impact of Drosophila Models in the Study and Treatment of Friedreich's Ataxia. Int J Mol Sci 2018; 19:E1989. [PMID: 29986523 PMCID: PMC6073496 DOI: 10.3390/ijms19071989] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 06/26/2018] [Accepted: 07/03/2018] [Indexed: 02/07/2023] Open
Abstract
Drosophila melanogaster has been for over a century the model of choice of several neurobiologists to decipher the formation and development of the nervous system as well as to mirror the pathophysiological conditions of many human neurodegenerative diseases. The rare disease Friedreich’s ataxia (FRDA) is not an exception. Since the isolation of the responsible gene more than two decades ago, the analysis of the fly orthologue has proven to be an excellent avenue to understand the development and progression of the disease, to unravel pivotal mechanisms underpinning the pathology and to identify genes and molecules that might well be either disease biomarkers or promising targets for therapeutic interventions. In this review, we aim to summarize the collection of findings provided by the Drosophila models but also to go one step beyond and propose the implications of these discoveries for the study and cure of this disorder. We will present the physiological, cellular and molecular phenotypes described in the fly, highlighting those that have given insight into the pathology and we will show how the ability of Drosophila to perform genetic and pharmacological screens has provided valuable information that is not easily within reach of other cellular or mammalian models.
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Affiliation(s)
- Véronique Monnier
- Unité de Biologie Fonctionnelle et Adaptative (BFA), Sorbonne Paris Cité, Université Paris Diderot, UMR8251 CNRS, 75013 Paris, France.
| | - Jose Vicente Llorens
- Department of Genetics, University of Valencia, Campus of Burjassot, 96100 Valencia, Spain.
| | - Juan Antonio Navarro
- Lehrstuhl für Entwicklungsbiologie, Universität Regensburg, 93040 Regensburg, Germany.
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14
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Steinkellner T, Zell V, Farino ZJ, Sonders MS, Villeneuve M, Freyberg RJ, Przedborski S, Lu W, Freyberg Z, Hnasko TS. Role for VGLUT2 in selective vulnerability of midbrain dopamine neurons. J Clin Invest 2018; 128:774-788. [PMID: 29337309 DOI: 10.1172/jci95795] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 11/21/2017] [Indexed: 12/22/2022] Open
Abstract
Parkinson's disease is characterized by the loss of dopamine (DA) neurons in the substantia nigra pars compacta (SNc). DA neurons in the ventral tegmental area are more resistant to this degeneration than those in the SNc, though the mechanisms for selective resistance or vulnerability remain poorly understood. A key to elucidating these processes may lie within the subset of DA neurons that corelease glutamate and express the vesicular glutamate transporter VGLUT2. Here, we addressed the potential relationship between VGLUT expression and DA neuronal vulnerability by overexpressing VGLUT in DA neurons of flies and mice. In Drosophila, VGLUT overexpression led to loss of select DA neuron populations. Similarly, expression of VGLUT2 specifically in murine SNc DA neurons led to neuronal loss and Parkinsonian behaviors. Other neuronal cell types showed no such sensitivity, suggesting that DA neurons are distinctively vulnerable to VGLUT2 expression. Additionally, most DA neurons expressed VGLUT2 during development, and coexpression of VGLUT2 with DA markers increased following injury in the adult. Finally, conditional deletion of VGLUT2 made DA neurons more susceptible to Parkinsonian neurotoxins. These data suggest that the balance of VGLUT2 expression is a crucial determinant of DA neuron survival. Ultimately, manipulation of this VGLUT2-dependent process may represent an avenue for therapeutic development.
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Affiliation(s)
| | - Vivien Zell
- Department of Neurosciences, UCSD, La Jolla, California, USA
| | - Zachary J Farino
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | | | - Michael Villeneuve
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Robin J Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Serge Przedborski
- Department of Neurology, and.,Department of Pathology and Cell Biology, Columbia University, New York, New York, USA
| | - Wei Lu
- Synapse and Neural Circuit Research Unit, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
| | - Zachary Freyberg
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Thomas S Hnasko
- Department of Neurosciences, UCSD, La Jolla, California, USA
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15
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Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease worldwide. It is known that there are many factors, either genetic or environmental factors, involved in PD, but the mechanism of PD is still not fully understood. Several animal models have been established to study the mechanisms of PD. Among these models, Drosophila melanogaster has been utilized as a valuable model to get insight into important features of PD. Drosophila melanogaster possesses a well-developed dopaminergic (DA) neuron system which is known to play an important role in PD pathogenesis. The well understanding of DA neurons from early larval through adult stage makes Drosophila as a powerful model for investigating the progressive neurodegeneration in PD. Besides, the short life cycle of Drosophila melanogaster serves an advantage in studying epidemiological features of PD. Most of PD symptoms can be mimicked in Drosophila model such as progressive impairment in locomotion, DA neuron degeneration, and some other non-motor symptoms. The Drosophila models of PD, therefore, show a great potential in application for PD genetic and drug screening.
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Affiliation(s)
- Vuu My Dung
- University of Science, Vietnam National University, Ho Chi Minh City, Vietnam
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16
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Sanz FJ, Solana-Manrique C, Muñoz-Soriano V, Calap-Quintana P, Moltó MD, Paricio N. Identification of potential therapeutic compounds for Parkinson's disease using Drosophila and human cell models. Free Radic Biol Med 2017; 108:683-691. [PMID: 28455141 DOI: 10.1016/j.freeradbiomed.2017.04.364] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 04/11/2017] [Accepted: 04/17/2017] [Indexed: 12/15/2022]
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease. It is caused by a loss of dopaminergic neurons in the substantia nigra pars compacta, leading to a decrease in dopamine levels in the striatum and thus producing movement impairment. Major physiological causes of neurodegeneration in PD are oxidative stress (OS) and mitochondrial dysfunction; these pathophysiological changes can be caused by both genetic and environmental factors. Although most PD cases are sporadic, it has been shown that 5-10% of them are familial forms caused by mutations in certain genes. One of these genes is the DJ-1 oncogene, which is involved in an early-onset recessive PD form. Currently, PD is an incurable disease for which existing therapies are not sufficiently effective to counteract or delay the progression of the disease. Therefore, the discovery of alternative drugs for the treatment of PD is essential. In this study we used a Drosophila PD model to identify candidate compounds with therapeutic potential for this disease. These flies carry a loss-of-function mutation in the DJ-1β gene, the Drosophila ortholog of human DJ-1, and show locomotor defects reflected by a reduced climbing ability. A pilot modifier chemical screen was performed, and several candidate compounds were identified based on their ability to improve locomotor activity of PD model flies. We demonstrated that some of them were also able to reduce OS levels in these flies. To validate the compounds identified in the Drosophila screen, a human cell PD model was generated by knocking down DJ-1 function in SH-SY5Y neuroblastoma cells. Our results showed that some of the compounds were also able to increase the viability of the DJ-1-deficient cells subjected to OS, thus supporting the use of Drosophila for PD drug discovery. Interestingly, some of them have been previously proposed as alternative therapies for PD or tested in clinical trials and others are first suggested in this study as potential drugs for the treatment of this disease.
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Affiliation(s)
- Francisco José Sanz
- Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, 46100 Burjassot, Spain; Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain
| | - Cristina Solana-Manrique
- Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, 46100 Burjassot, Spain; Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain
| | - Verónica Muñoz-Soriano
- Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, 46100 Burjassot, Spain; Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain
| | - Pablo Calap-Quintana
- Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, 46100 Burjassot, Spain
| | - María Dolores Moltó
- Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, 46100 Burjassot, Spain; CIBERSAM, INCLIVA. Valencia, Spain
| | - Nuria Paricio
- Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, 46100 Burjassot, Spain; Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, 46100 Burjassot, Spain.
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17
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I Believe I Can Fly!: Use of Drosophila as a Model Organism in Neuropsychopharmacology Research. Neuropsychopharmacology 2016; 41:1439-46. [PMID: 26576740 PMCID: PMC4832023 DOI: 10.1038/npp.2015.322] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 10/14/2015] [Accepted: 10/16/2015] [Indexed: 01/03/2023]
Abstract
Neuropsychiatric disorders are of complex etiology, often including a large genetic component. In order to help identify and study the molecular and physiological mechanisms that such genes participate in, numerous animal models have been established in a variety of species. Over the past decade, this has increasingly included the vinegar fly, Drosophila melanogaster. Here, we outline why we study an invertebrate organism in the context of neuropsychiatric disorders, and we discuss how we can gain insight from studies in Drosophila. We focus on a few disorders and findings to make the larger point that modeling these diseases in flies can have both mechanistic and predictive validity. Highlighting some translational examples, we underline the fact that their brains works more like ours than one would have anticipated.
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18
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Hannan SB, Dräger NM, Rasse TM, Voigt A, Jahn TR. Cellular and molecular modifier pathways in tauopathies: the big picture from screening invertebrate models. J Neurochem 2016; 137:12-25. [PMID: 26756400 DOI: 10.1111/jnc.13532] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/14/2015] [Accepted: 01/04/2016] [Indexed: 12/16/2022]
Abstract
Abnormal tau accumulations were observed and documented in post-mortem brains of patients affected by Alzheimer's disease (AD) long before the identification of mutations in the Microtubule-associated protein tau (MAPT) gene, encoding the tau protein, in a different neurodegenerative disease called Frontotemporal dementia and Parkinsonism linked to chromosome 17 (FTDP-17). The discovery of mutations in the MAPT gene associated with FTDP-17 highlighted that dysfunctions in tau alone are sufficient to cause neurodegeneration. Invertebrate models have been diligently utilized in investigating tauopathies, contributing to the understanding of cellular and molecular pathways involved in disease etiology. An important discovery came with the demonstration that over-expression of human tau in Drosophila leads to premature mortality and neuronal dysfunction including neurodegeneration, recapitulating some key neuropathological features of the human disease. The simplicity of handling invertebrate models combined with the availability of a diverse range of experimental resources make these models, in particular Drosophila a powerful invertebrate screening tool. Consequently, several large-scale screens have been performed using Drosophila, to identify modifiers of tau toxicity. The screens have revealed not only common cellular and molecular pathways, but in some instances the same modifier has been independently identified in two or more screens suggesting a possible role for these modifiers in regulating tau toxicity. The purpose of this review is to discuss the genetic modifier screens on tauopathies performed in Drosophila and C. elegans models, and to highlight the common cellular and molecular pathways that have emerged from these studies. Here, we summarize results of tau toxicity screens providing mechanistic insights into pathological alterations in tauopathies. Key pathways or modifiers that have been identified are associated with a broad range of processes including, but not limited to, phosphorylation, cytoskeleton organization, axonal transport, regulation of cellular proteostasis, transcription, RNA metabolism, cell cycle regulation, and apoptosis. We discuss the utility and application of invertebrate models in elucidating the cellular and molecular functions of novel and uncharacterized disease modifiers identified in large-scale screens as well as for investigating the function of genes identified as risk factors in genome-wide association studies from human patients in the post-genomic era. In this review, we combined and summarized several large-scale modifier screens performed in invertebrate models to identify modifiers of tau toxicity. A summary of the screens show that diverse cellular processes are implicated in the modification of tau toxicity. Kinases and phosphatases are the most predominant class of modifiers followed by components required for cellular proteostasis and axonal transport and cytoskeleton elements.
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Affiliation(s)
- Shabab B Hannan
- Schaller Research Group at the University of Heidelberg and DKFZ, Proteostasis in Neurodegenerative Disease (B180), German Cancer Research Center, Heidelberg, Germany.,Graduate School of Cellular and Molecular Neuroscience, Graduate Training Center of Neuroscience, University of Tübingen, Tübingen, Germany
| | - Nina M Dräger
- Schaller Research Group at the University of Heidelberg and DKFZ, Proteostasis in Neurodegenerative Disease (B180), German Cancer Research Center, Heidelberg, Germany
| | - Tobias M Rasse
- Schaller Research Group at the University of Heidelberg and DKFZ, Proteostasis in Neurodegenerative Disease (B180), German Cancer Research Center, Heidelberg, Germany
| | - Aaron Voigt
- Department of Neurology at University Clinic Aachen, RWTH Aachen, Germany
| | - Thomas R Jahn
- Schaller Research Group at the University of Heidelberg and DKFZ, Proteostasis in Neurodegenerative Disease (B180), German Cancer Research Center, Heidelberg, Germany
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19
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Martin CA, Barajas A, Lawless G, Lawal HO, Assani K, Lumintang YP, Nunez V, Krantz DE. Synergistic effects on dopamine cell death in a Drosophila model of chronic toxin exposure. Neurotoxicology 2014; 44:344-51. [PMID: 25160001 PMCID: PMC4264678 DOI: 10.1016/j.neuro.2014.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 08/08/2014] [Accepted: 08/11/2014] [Indexed: 01/06/2023]
Abstract
The neurodegenerative effects of Parkinson's disease (PD) are marked by a selective loss of dopaminergic (DA) neurons. Epidemiological studies suggest that chronic exposure to the pesticide paraquat may increase the risk for PD and DA cell loss. However, combined exposure with additional fungicide(s) including maneb and/or ziram may be required for pathogenesis. To explore potential pathogenic mechanisms, we have developed a Drosophila model of chronic paraquat exposure. We find that while chronic paraquat exposure alone decreased organismal survival and motor function, combined chronic exposure to both paraquat and maneb was required for DA cell death in the fly. To initiate mechanistic studies of this interaction, we used additional genetic reagents to target the ubiquitin proteasome system, which has been implicated in some rare familial forms of PD and the toxic effects of ziram. Genetic inhibition of E1 ubiquitin ligase, but not the proteasome itself, increased DA cell death in combination with maneb but not paraquat. These studies establish a model for long-term exposure to multiple pesticides, and support the idea that pesticide interactions relevant to PD may involve inhibition of protein ubiquitination.
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Affiliation(s)
- Ciara A Martin
- UCLA Interdepartmental Program in Molecular Toxicology, Los Angeles, CA 90095, United States.
| | - Angel Barajas
- Department of Psychiatry and Biobehavioral Sciences, The Gonda (Goldschmied) Neuroscience and Genetics Research Center, Room 3335, Hatos Center For Neuropharmacology, David Geffen School of Medicine, University of California Los Angeles, 695 Charles E. Young Drive South, Los Angeles, CA 90095, United States.
| | - George Lawless
- Department of Psychiatry and Biobehavioral Sciences, The Gonda (Goldschmied) Neuroscience and Genetics Research Center, Room 3335, Hatos Center For Neuropharmacology, David Geffen School of Medicine, University of California Los Angeles, 695 Charles E. Young Drive South, Los Angeles, CA 90095, United States.
| | - Hakeem O Lawal
- UCLA Interdepartmental Program in Molecular Toxicology, Los Angeles, CA 90095, United States; Department of Psychiatry and Biobehavioral Sciences, The Gonda (Goldschmied) Neuroscience and Genetics Research Center, Room 3335, Hatos Center For Neuropharmacology, David Geffen School of Medicine, University of California Los Angeles, 695 Charles E. Young Drive South, Los Angeles, CA 90095, United States.
| | - Khadij Assani
- Department of Psychiatry and Biobehavioral Sciences, The Gonda (Goldschmied) Neuroscience and Genetics Research Center, Room 3335, Hatos Center For Neuropharmacology, David Geffen School of Medicine, University of California Los Angeles, 695 Charles E. Young Drive South, Los Angeles, CA 90095, United States.
| | - Yosephine P Lumintang
- Department of Psychiatry and Biobehavioral Sciences, The Gonda (Goldschmied) Neuroscience and Genetics Research Center, Room 3335, Hatos Center For Neuropharmacology, David Geffen School of Medicine, University of California Los Angeles, 695 Charles E. Young Drive South, Los Angeles, CA 90095, United States.
| | - Vanessa Nunez
- Department of Psychiatry and Biobehavioral Sciences, The Gonda (Goldschmied) Neuroscience and Genetics Research Center, Room 3335, Hatos Center For Neuropharmacology, David Geffen School of Medicine, University of California Los Angeles, 695 Charles E. Young Drive South, Los Angeles, CA 90095, United States.
| | - David E Krantz
- UCLA Interdepartmental Program in Molecular Toxicology, Los Angeles, CA 90095, United States; Department of Psychiatry and Biobehavioral Sciences, The Gonda (Goldschmied) Neuroscience and Genetics Research Center, Room 3335, Hatos Center For Neuropharmacology, David Geffen School of Medicine, University of California Los Angeles, 695 Charles E. Young Drive South, Los Angeles, CA 90095, United States.
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20
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Genetic animal models of dystonia: common features and diversities. Prog Neurobiol 2014; 121:91-113. [PMID: 25034123 DOI: 10.1016/j.pneurobio.2014.07.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 06/06/2014] [Accepted: 07/03/2014] [Indexed: 01/13/2023]
Abstract
Animal models are pivotal for studies of pathogenesis and treatment of disorders of the central nervous system which in its complexity cannot yet be modeled in vitro or using computer simulations. The choice of a specific model to test novel therapeutic strategies for a human disease should be based on validity of the model for the approach: does the model reflect symptoms, pathogenesis and treatment response present in human patients? In the movement disorder dystonia, prior to the availability of genetically engineered mice, spontaneous mutants were chosen based on expression of dystonic features, including abnormal muscle contraction, movements and postures. Recent discovery of a number of genes and gene products involved in dystonia initiated research on pathogenesis of the disorder, and the creation of novel models based on gene mutations. Here we present a review of current models of dystonia, with a focus on genetic rodent models, which will likely be first choice in the future either for pathophysiological or for preclinical drug testing or both. In order to help selection of a model depending on expression of a specific feature of dystonia, this review is organized by symptoms and current knowledge of pathogenesis of dystonia. We conclude that albeit there is increasing need for research on pathogenesis of the disease and development of improved models, current models do replicate features of dystonia and are useful tools to develop urgently demanded treatment for this debilitating disorder.
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21
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Drosophila melanogaster as a genetic model system to study neurotransmitter transporters. Neurochem Int 2014; 73:71-88. [PMID: 24704795 DOI: 10.1016/j.neuint.2014.03.015] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 03/20/2014] [Accepted: 03/24/2014] [Indexed: 12/30/2022]
Abstract
The model genetic organism Drosophila melanogaster, commonly known as the fruit fly, uses many of the same neurotransmitters as mammals and very similar mechanisms of neurotransmitter storage, release and recycling. This system offers a variety of powerful molecular-genetic methods for the study of transporters, many of which would be difficult in mammalian models. We review here progress made using Drosophila to understand the function and regulation of neurotransmitter transporters and discuss future directions for its use.
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22
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Bernstein AI, Stout KA, Miller GW. The vesicular monoamine transporter 2: an underexplored pharmacological target. Neurochem Int 2014; 73:89-97. [PMID: 24398404 DOI: 10.1016/j.neuint.2013.12.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 12/06/2013] [Accepted: 12/09/2013] [Indexed: 12/21/2022]
Abstract
Active transport of neurotransmitters into synaptic vesicles is required for their subsequent exocytotic release. In the monoamine system, this process is carried out by the vesicular monoamine transporters (VMAT1 and VMAT2). These proteins are responsible for vesicular packaging of dopamine, norepinephrine, serotonin, and histamine. These proteins are essential for proper neuronal function; however, compared to their plasma membrane counterparts, there are few drugs available that target these vesicular proteins. This is partly due to the added complexity of crossing the plasma membrane, but also to the technical difficulty of assaying for vesicular uptake in high throughput. Until recently, reagents to enable high throughput screening for function of these vesicular neurotransmitter transporters have not been available. Fortunately, novel compounds and methods are now making such screening possible; thus, a renewed focus on these transporters as potential targets is timely and necessary.
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Affiliation(s)
- Alison I Bernstein
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - Kristen A Stout
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - Gary W Miller
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA; Center for Neurodegenerative Diseases, Emory University, Atlanta, GA 30322, USA; Department of Pharmacology, Emory University, Atlanta, GA 30322, USA; Department of Neurology, Emory University, Atlanta, GA 30322, USA.
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23
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Lenz S, Karsten P, Schulz JB, Voigt A. Drosophila as a screening tool to study human neurodegenerative diseases. J Neurochem 2013; 127:453-60. [PMID: 24028575 DOI: 10.1111/jnc.12446] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 08/22/2013] [Accepted: 09/03/2013] [Indexed: 11/28/2022]
Abstract
In an aging society, research involving neurodegenerative disorders is of paramount importance. Over the past few years, research on Alzheimer's and Parkinson's diseases has made tremendous progress. Experimental studies, however, rely mostly on transgenic animal models, preferentially using mice. Although experiments on mice have enormous advantages, they also have some inherent limitations, some of which can be overcome by the use of Drosophila melanogaster as an experimental animal. Among the major advantages of using the fly is its small genome, which can also be modified very easily. The fact that its genome lends itself to diverse alterations (e. g. mutagenesis, transposons) has made the fly a useful organism to perform large-scale and genome-wide screening approaches. This has opened up an entirely new field of experimental research aiming to elucidate genetic interactions and screen for modifiers of disease processes in vivo. Here, we provide a brief overview of how flies can be used to analyze molecular mechanisms underlying human neurodegenerative diseases.
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Affiliation(s)
- Sarah Lenz
- Department of Neurology, University Medical Center, RWTH Aachen, Aachen, Germany
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24
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Hurd TR, Leblanc MG, Jones LN, DeGennaro M, Lehmann R. Genetic modifier screens to identify components of a redox-regulated cell adhesion and migration pathway. Methods Enzymol 2013; 528:197-215. [PMID: 23849867 DOI: 10.1016/b978-0-12-405881-1.00012-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Under normal physiological conditions, cells use oxidants, particularly H2O2, for signal transduction during processes such as proliferation and migration. Though recent progress has been made in determining the precise role H2O2 plays in these processes, many gaps still remain. To further understand this, we describe the use of a dominant enhancer screen to identify novel components of a redox-regulated cell migration and adhesion pathway in Drosophila melanogaster. Here, we discuss our methodology and progress as well as the benefits and limitations of applying such an approach to study redox-regulated pathways. Depending on the nature of these pathways, unbiased genetic modifier screens may prove a productive way to identify novel redox-regulated signaling components.
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Affiliation(s)
- Thomas Ryan Hurd
- Department of Cell Biology, HHMI and Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, USA.
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