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Bhandari A, Seguin A, Rothenfluh A. Synaptic Mechanisms of Ethanol Tolerance and Neuroplasticity: Insights from Invertebrate Models. Int J Mol Sci 2024; 25:6838. [PMID: 38999947 PMCID: PMC11241699 DOI: 10.3390/ijms25136838] [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: 05/06/2024] [Revised: 06/09/2024] [Accepted: 06/10/2024] [Indexed: 07/14/2024] Open
Abstract
Alcohol tolerance is a neuroadaptive response that leads to a reduction in the effects of alcohol caused by previous exposure. Tolerance plays a critical role in the development of alcohol use disorder (AUD) because it leads to the escalation of drinking and dependence. Understanding the molecular mechanisms underlying alcohol tolerance is therefore important for the development of effective therapeutics and for understanding addiction in general. This review explores the molecular basis of alcohol tolerance in invertebrate models, Drosophila and C. elegans, focusing on synaptic transmission. Both organisms exhibit biphasic responses to ethanol and develop tolerance similar to that of mammals. Furthermore, the availability of several genetic tools makes them a great candidate to study the molecular basis of ethanol response. Studies in invertebrate models show that tolerance involves conserved changes in the neurotransmitter systems, ion channels, and synaptic proteins. These neuroadaptive changes lead to a change in neuronal excitability, most likely to compensate for the enhanced inhibition by ethanol.
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Affiliation(s)
- Aakriti Bhandari
- Department of Psychiatry, University of Utah, Salt Lake City, UT 84112, USA
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
- Neuroscience Graduate Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Alexandra Seguin
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Adrian Rothenfluh
- Department of Psychiatry, University of Utah, Salt Lake City, UT 84112, USA
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
- Neuroscience Graduate Program, University of Utah, Salt Lake City, UT 84112, USA
- Department of Neurobiology, University of Utah, Salt Lake City, UT 84112, USA
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
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2
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You Y, Katti S, Yu B, Igumenova TI, Das J. Probing the Diacylglycerol Binding Site of Presynaptic Munc13-1. Biochemistry 2021; 60:1286-1298. [PMID: 33818064 PMCID: PMC8906797 DOI: 10.1021/acs.biochem.1c00165] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Munc13-1 is a presynaptic active zone protein that acts as a master regulator of synaptic vesicle priming and neurotransmitter release in the brain. It has been implicated in the pathophysiology of several neurodegenerative diseases. Diacylglycerol and phorbol ester activate Munc13-1 by binding to its C1 domain. The objective of this study is to identify the structural determinants of ligand binding activity of the Munc13-1 C1 domain. Molecular docking suggested that residues Trp-588, Ile-590, and Arg-592 of Munc13-1 are involved in ligand interactions. To elucidate the role of these three residues in ligand binding, we generated W588A, I590A, and R592A mutants in full-length Munc13-1, expressed them as GFP-tagged proteins in HT22 cells, and measured their ligand-induced membrane translocation by confocal microscopy and immunoblotting. The extent of 1,2-dioctanoyl-sn-glycerol (DOG)- and phorbol ester-induced membrane translocation decreased in the following order: wild type > I590A > W588A > R592A and wild type > W588A > I590A > R592A, respectively. To understand the effect of the mutations on ligand binding, we also measured the DOG binding affinity of the isolated wild-type C1 domain and its mutants in membrane-mimicking micelles using nuclear magnetic resonance methods. The DOG binding affinity decreased in the following order: wild type > I590A > R592A. No binding was detected for W588A with DOG in micelles. This study shows that Trp-588, Ile-590, and Arg-592 are essential determinants for the activity of Munc13-1 and the effects of the three residues on the activity are ligand-dependent. This study bears significance for the development of selective modulators of Munc13-1.
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Affiliation(s)
- Youngki You
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy, Health 2, University of Houston, Houston, Texas 77204, United States
| | - Sachin Katti
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, Texas 77843, United States
| | - Binhan Yu
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, Texas 77843, United States
| | - Tatyana I Igumenova
- Department of Biochemistry and Biophysics, Texas A&M University, 300 Olsen Boulevard, College Station, Texas 77843, United States
| | - Joydip Das
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy, Health 2, University of Houston, Houston, Texas 77204, United States
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3
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Das J. SNARE Complex-Associated Proteins and Alcohol. Alcohol Clin Exp Res 2019; 44:7-18. [PMID: 31724225 DOI: 10.1111/acer.14238] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 11/07/2019] [Indexed: 12/23/2022]
Abstract
Alcohol addiction causes major health problems throughout the world, causing numerous deaths and incurring a huge economic burden to society. To develop an intervention for alcohol addiction, it is necessary to identify molecular target(s) of alcohol and associated molecular mechanisms of alcohol action. The functions of many central and peripheral synapses are impacted by low concentrations of ethanol (EtOH). While the postsynaptic targets and mechanisms are studied extensively, there are limited studies on the presynaptic targets and mechanisms. This article is an endeavor in this direction, focusing on the effect of EtOH on the presynaptic proteins associated with the neurotransmitter release machinery. Studies on the effects of EtOH at the levels of gene, protein, and behavior are highlighted in this article.
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Affiliation(s)
- Joydip Das
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas
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4
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Blanco FA, Czikora A, Kedei N, You Y, Mitchell GA, Pany S, Ghosh A, Blumberg PM, Das J. Munc13 Is a Molecular Target of Bryostatin 1. Biochemistry 2019; 58:3016-3030. [PMID: 31243993 PMCID: PMC6620733 DOI: 10.1021/acs.biochem.9b00427] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
![]()
Bryostatin
1 is a natural macrolide shown to improve neuronal connections and
enhance memory in mice. Its mechanism of action is largely attributed
to the modulation of novel and conventional protein kinase Cs (PKCs)
by binding to their regulatory C1 domains. Munc13-1 is a C1 domain-containing
protein that shares common endogenous and exogenous activators with
novel and conventional PKC subtypes. Given the essential role of Munc13-1
in the priming of synaptic vesicles and neuronal transmission overall,
we explored the potential interaction between bryostatin 1 and Munc13-1.
Our results indicate that in vitro bryostatin 1 binds
to both the isolated C1 domain of Munc13-1 (Ki = 8.07 ± 0.90 nM) and the full-length Munc13-1 protein
(Ki = 0.45 ± 0.04 nM). Furthermore,
confocal microscopy and immunoblot analysis demonstrated that in intact
HT22 cells bryostatin 1 mimics the actions of phorbol esters, a previously
established class of Munc13-1 activators, and induces plasma membrane
translocation of Munc13-1, a hallmark of its activation. Consistently,
bryostatin 1 had no effect on the Munc13-1H567K construct
that is insensitive to phorbol esters. Effects of bryostatin 1 on
the other Munc13 family members, ubMunc13-2 and bMunc13-2, resembled
those of Munc13-1 for translocation. Lastly, we observed an increased
level of expression of Munc13-1 following a 24 h incubation with bryostatin
1 in both HT22 and primary mouse hippocampal cells. This study characterizes
Munc13-1 as a molecular target of bryostatin 1. Considering the crucial
role of Munc13-1 in neuronal function, these findings provide strong
support for the potential role of Munc13s in the actions of bryostatin
1.
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Affiliation(s)
- Francisco A Blanco
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy , University of Houston , Houston , Texas 77204 , United States
| | - Agnes Czikora
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute , National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Noemi Kedei
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute , National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Youngki You
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy , University of Houston , Houston , Texas 77204 , United States
| | - Gary A Mitchell
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute , National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Satyabrata Pany
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy , University of Houston , Houston , Texas 77204 , United States
| | - Anamitra Ghosh
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy , University of Houston , Houston , Texas 77204 , United States
| | - Peter M Blumberg
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute , National Institutes of Health , Bethesda , Maryland 20892 , United States
| | - Joydip Das
- Department of Pharmacological & Pharmaceutical Sciences, College of Pharmacy , University of Houston , Houston , Texas 77204 , United States
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Farris SP, Riley BP, Williams RW, Mulligan MK, Miles MF, Lopez MF, Hitzemann R, Iancu OD, Colville A, Walter NAR, Darakjian P, Oberbeck DL, Daunais JB, Zheng CL, Searles RP, McWeeney SK, Grant KA, Mayfield RD. Cross-species molecular dissection across alcohol behavioral domains. Alcohol 2018; 72:19-31. [PMID: 30213503 PMCID: PMC6309876 DOI: 10.1016/j.alcohol.2017.11.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 11/17/2017] [Accepted: 11/28/2017] [Indexed: 12/14/2022]
Abstract
This review summarizes the proceedings of a symposium presented at the "Alcoholism and Stress: A Framework for Future Treatment Strategies" conference held in Volterra, Italy on May 9-12, 2017. Psychiatric diseases, including alcohol-use disorders (AUDs), are influenced through complex interactions of genes, neurobiological pathways, and environmental influences. A better understanding of the common neurobiological mechanisms underlying an AUD necessitates an integrative approach, involving a systematic assessment of diverse species and phenotype measures. As part of the World Congress on Stress and Alcoholism, this symposium provided a detailed account of current strategies to identify mechanisms underlying the development and progression of AUDs. Dr. Sean Farris discussed the integration and organization of transcriptome and postmortem human brain data to identify brain regional- and cell type-specific differences related to excessive alcohol consumption that are conserved across species. Dr. Brien Riley presented the results of a genome-wide association study of DSM-IV alcohol dependence; although replication of genetic associations with alcohol phenotypes in humans remains challenging, model organism studies show that COL6A3, KLF12, and RYR3 affect behavioral responses to ethanol, and provide substantial evidence for their role in human alcohol-related traits. Dr. Rob Williams expanded upon the systematic characterization of extensive genetic-genomic resources for quantifying and clarifying phenotypes across species that are relevant to precision medicine in human disease. The symposium concluded with Dr. Robert Hitzemann's description of transcriptome studies in a mouse model selectively bred for high alcohol ("binge-like") consumption and a non-human primate model of long-term alcohol consumption. Together, the different components of this session provided an overview of systems-based approaches that are pioneering the experimental prioritization and validation of novel genes and gene networks linked with a range of behavioral phenotypes associated with stress and AUDs.
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Affiliation(s)
- Sean P Farris
- University of Texas at Austin, Austin, TX, United States
| | - Brien P Riley
- Virginia Commonwealth University, Richmond, VA, United States
| | - Robert W Williams
- University of Tennessee Health Science Center, Memphis, TN, United States
| | - Megan K Mulligan
- University of Tennessee Health Science Center, Memphis, TN, United States
| | - Michael F Miles
- University of Tennessee Health Science Center, Memphis, TN, United States
| | - Marcelo F Lopez
- University of Tennessee Health Science Center, Memphis, TN, United States
| | - Robert Hitzemann
- Oregon Health and Science University, Portland, OR, United States
| | - Ovidiu D Iancu
- Oregon Health and Science University, Portland, OR, United States
| | | | | | | | | | - James B Daunais
- Wake Forest School of Medicine, Winston-Salem, NC, United States
| | | | - Robert P Searles
- Oregon Health and Science University, Portland, OR, United States
| | | | - Kathleen A Grant
- Oregon Health and Science University, Portland, OR, United States
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Ethanol Regulates Presynaptic Activity and Sedation through Presynaptic Unc13 Proteins in Drosophila. eNeuro 2018; 5:eN-NWR-0125-18. [PMID: 29911175 PMCID: PMC6001265 DOI: 10.1523/eneuro.0125-18.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 05/09/2018] [Accepted: 05/12/2018] [Indexed: 11/21/2022] Open
Abstract
Ethanol has robust effects on presynaptic activity in many neurons, however, it is not yet clear how this drug acts within this compartment to change neural activity, nor the significance of this change on behavior and physiology in vivo. One possible presynaptic effector for ethanol is the Munc13-1 protein. Herein, we show that ethanol binding to the rat Munc13-1 C1 domain, at concentrations consistent with binge exposure, reduces diacylglycerol (DAG) binding. The inhibition of DAG binding is predicted to reduce the activity of Munc13-1 and presynaptic release. In Drosophila, we show that sedating concentrations of ethanol significantly reduce synaptic vesicle release in olfactory sensory neurons (OSNs), while having no significant impact on membrane depolarization and Ca2+ influx into the presynaptic compartment. These data indicate that ethanol targets the active zone in reducing synaptic vesicle exocytosis. Drosophila, haploinsufficent for the Munc13-1 ortholog Dunc13, are more resistant to the effect of ethanol on presynaptic inhibition. Genetically reducing the activity of Dunc13 through mutation or expression of RNAi transgenes also leads to a significant resistance to the sedative effects of ethanol. The neuronal expression of Munc13-1 in heterozygotes for a Dunc13 loss-of-function mutation can largely rescue the ethanol sedation resistance phenotype, indicating a conservation of function between Munc13-1 and Dunc13 in ethanol sedation. Hence, reducing Dunc13 activity leads to naïve physiological and behavioral resistance to sedating concentrations of ethanol. We propose that reducing Dunc13 activity, genetically or pharmacologically by ethanol binding to the C1 domain of Munc13-1/Dunc13, promotes a homeostatic response that leads to ethanol tolerance.
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Ethanol Stimulates Locomotion via a G αs-Signaling Pathway in IL2 Neurons in Caenorhabditis elegans. Genetics 2017; 207:1023-1039. [PMID: 28951527 PMCID: PMC5676223 DOI: 10.1534/genetics.117.300119] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 09/23/2017] [Indexed: 01/21/2023] Open
Abstract
Alcohol abuse is among the top causes of preventable death, generating considerable financial, health, and societal burdens. Paradoxically, alcohol... Alcohol is a potent pharmacological agent when consumed acutely at sufficient quantities and repeated overuse can lead to addiction and deleterious effects on health. Alcohol is thought to modulate neuronal function through low-affinity interactions with proteins, in particular with membrane channels and receptors. Paradoxically, alcohol acts as both a stimulant and a sedative. The exact molecular mechanisms for the acute effects of ethanol on neurons, as either a stimulant or a sedative, however remain unclear. We investigated the role that the heat shock transcription factor HSF-1 played in determining a stimulatory phenotype of Caenorhabditis elegans in response to physiologically relevant concentrations of ethanol (17 mM; 0.1% v/v). Using genetic techniques, we demonstrate that either RNA interference of hsf-1 or use of an hsf-1(sy441) mutant lacked the enhancement of locomotion in response to acute ethanol exposure evident in wild-type animals. We identify that the requirement for HSF-1 in this phenotype was IL2 neuron-specific and required the downstream expression of the α-crystallin ortholog HSP-16.48. Using a combination of pharmacology, optogenetics, and phenotypic analyses we determine that ethanol activates a Gαs-cAMP-protein kinase A signaling pathway in IL2 neurons to stimulate nematode locomotion. We further implicate the phosphorylation of a specific serine residue (Ser322) on the synaptic protein UNC-18 as an end point for the Gαs-dependent signaling pathway. These findings establish and characterize a distinct neurosensory cell signaling pathway that determines the stimulatory action of ethanol and identifies HSP-16.48 and HSF-1 as novel regulators of this pathway.
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8
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Adkins AE, Hack LM, Bigdeli TB, Williamson VS, McMichael GO, Mamdani M, Edwards A, Aliev F, Chan RF, Bhandari P, Raabe RC, Alaimo JT, Blackwell GG, Moscati AA, Poland RS, Rood B, Patterson DG, Walsh D, Whitfield JB, Zhu G, Montgomery GW, Henders AK, Martin NG, Heath AC, Madden PA, Frank J, Ridinger M, Wodarz N, Soyka M, Zill P, Ising M, Nöthen MM, Kiefer F, Rietschel M, Gelernter J, Sherva R, Koesterer R, Almasy L, Zhao H, Kranzler HR, Farrer LA, Maher BS, Prescott CA, Dick DM, Bacanu SA, Mathies LD, Davies AG, Vladimirov VI, Grotewiel M, Bowers MS, Bettinger JC, Webb BT, Miles MF, Kendler KS, Riley BP. Genomewide Association Study of Alcohol Dependence Identifies Risk Loci Altering Ethanol-Response Behaviors in Model Organisms. Alcohol Clin Exp Res 2017; 41:911-928. [PMID: 28226201 PMCID: PMC5404949 DOI: 10.1111/acer.13362] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 02/16/2017] [Indexed: 01/23/2023]
Abstract
BACKGROUND Alcohol dependence (AD) shows evidence for genetic liability, but genes influencing risk remain largely unidentified. METHODS We conducted a genomewide association study in 706 related AD cases and 1,748 unscreened population controls from Ireland. We sought replication in 15,496 samples of European descent. We used model organisms (MOs) to assess the role of orthologous genes in ethanol (EtOH)-response behaviors. We tested 1 primate-specific gene for expression differences in case/control postmortem brain tissue. RESULTS We detected significant association in COL6A3 and suggestive association in 2 previously implicated loci, KLF12 and RYR3. None of these signals are significant in replication. A suggestive signal in the long noncoding RNA LOC339975 is significant in case:control meta-analysis, but not in a population sample. Knockdown of a COL6A3 ortholog in Caenorhabditis elegans reduced EtOH sensitivity. Col6a3 expression correlated with handling-induced convulsions in mice. Loss of function of the KLF12 ortholog in C. elegans impaired development of acute functional tolerance (AFT). Klf12 expression correlated with locomotor activation following EtOH injection in mice. Loss of function of the RYR3 ortholog reduced EtOH sensitivity in C. elegans and rapid tolerance in Drosophila. The ryanodine receptor antagonist dantrolene reduced motivation to self-administer EtOH in rats. Expression of LOC339975 does not differ between cases and controls but is reduced in carriers of the associated rs11726136 allele in nucleus accumbens (NAc). CONCLUSIONS We detect association between AD and COL6A3, KLF12, RYR3, and LOC339975. Despite nonreplication of COL6A3, KLF12, and RYR3 signals, orthologs of these genes influence behavioral response to EtOH in MOs, suggesting potential involvement in human EtOH response and AD liability. The associated LOC339975 allele may influence gene expression in human NAc. Although the functions of long noncoding RNAs are poorly understood, there is mounting evidence implicating these genes in multiple brain functions and disorders.
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Affiliation(s)
- Amy E. Adkins
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
| | - Laura M. Hack
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
| | - Tim B. Bigdeli
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
| | - Vernell S. Williamson
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
| | - G. Omari McMichael
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
| | - Mohammed Mamdani
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
| | - Alexis Edwards
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
| | - Fazil Aliev
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
| | - Robin F. Chan
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Human & Molecular Genetics, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - Poonam Bhandari
- Department of Human & Molecular Genetics, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - Richard C. Raabe
- Department of Pharmacology & Toxicology, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - Joseph T. Alaimo
- Department of Pharmacology & Toxicology, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - GinaMari G. Blackwell
- Department of Pharmacology & Toxicology, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - Arden A. Moscati
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
| | - Ryan S. Poland
- Department of Pharmacology & Toxicology, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - Benjamin Rood
- Department of Pharmacology & Toxicology, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - Diana G. Patterson
- Shaftesbury Square Hospital, 116-120 Great Victoria Street, Belfast,
BT2 7BG, United Kingdom
| | - Dermot Walsh
- Health Research Board, 67-72 Lower Mount Street, Dublin 2,
Ireland
| | | | - John B. Whitfield
- Genetic Epidemiology, QIMR Berghofer Medical Research Institute,
Royal Brisbane and Women’s Hospital, 300 Herston Road, Brisbane, QLD 4006,
Australia
| | - Gu Zhu
- Genetic Epidemiology, QIMR Berghofer Medical Research Institute,
Royal Brisbane and Women’s Hospital, 300 Herston Road, Brisbane, QLD 4006,
Australia
| | - Grant W. Montgomery
- Genetic Epidemiology, QIMR Berghofer Medical Research Institute,
Royal Brisbane and Women’s Hospital, 300 Herston Road, Brisbane, QLD 4006,
Australia
| | - Anjali K. Henders
- Genetic Epidemiology, QIMR Berghofer Medical Research Institute,
Royal Brisbane and Women’s Hospital, 300 Herston Road, Brisbane, QLD 4006,
Australia
| | - Nicholas G. Martin
- Genetic Epidemiology, QIMR Berghofer Medical Research Institute,
Royal Brisbane and Women’s Hospital, 300 Herston Road, Brisbane, QLD 4006,
Australia
| | - Andrew C. Heath
- Department of Psychiatry, Washington University School of Medicine,
4560 Clayton Ave., Suite 1000, St. Louis, MO, 63110, USA
| | - Pamela A.F. Madden
- Department of Psychiatry, Washington University School of Medicine,
4560 Clayton Ave., Suite 1000, St. Louis, MO, 63110, USA
| | - Josef Frank
- Department of Genetic Epidemiology in Psychiatry, Central Institute
of Mental Health, Medical Faculty Mannheim/Heidelberg University, J 5, 68159
Mannheim, Germany
| | - Monika Ridinger
- Department of Psychiatry, University Hospital Regensburg,
University of Regensburg, 93042 Regensburg, Germany
| | - Norbert Wodarz
- Department of Psychiatry, University Hospital Regensburg,
University of Regensburg, 93042 Regensburg, Germany
| | - Michael Soyka
- Privatklinik Meiringen, Willigen, 3860 Meiringen, Switzerland
- Department of Psychiatry and Psychotherapy, University of Munich,
Nussbaumstrasse 7, 80336 Munich, Germany
| | - Peter Zill
- Department of Psychiatry and Psychotherapy, University of Munich,
Nussbaumstrasse 7, 80336 Munich, Germany
| | - Marcus Ising
- Department of Molecular Psychology, Max-Planck-Institute of
Psychiatry, Kraepelinstrasse 2–10, 80804 Munich, Germany
| | - Markus M Nöthen
- Department of Genomics, Life & Brain Center, University of
Bonn, Sigmund-Freud-Strasse 25, D-53127 Bonn, Germany
- Department of Institute of Human Genetics, University of Bonn,
Sigmund-Freud-Strasse 25, D-53127 Bonn, Germany
- German Center for Neurodegenerative Diseases (DZNE), University of
Bonn, Sigmund-Freud-Strasse 25, D-53127 Bonn, Germany
| | - Falk Kiefer
- Department of Addictive Behavior and Addiction Medicine, Central
Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, J 5,
68159 Mannheim, Germany
| | - Marcella Rietschel
- Department of Genetic Epidemiology in Psychiatry, Central Institute
of Mental Health, Medical Faculty Mannheim/Heidelberg University, J 5, 68159
Mannheim, Germany
| | | | - Joel Gelernter
- Department of Psychiatry, Yale University School of Medicine, 333
Cedar Street, New Haven, CT, 06510, USA
- Department of Neurobiology, Yale University School of Medicine, 333
Cedar Street, New Haven, CT, 06510, USA
- Department of Genetics, Yale University School of Medicine, 333
Cedar Street, New Haven, CT, 06510, USA
- Department of Psychiatry, VA CT Healthcare Center, 950 Campbell
Avenue, West Haven, CT, 06516, USA
| | - Richard Sherva
- Department of Medicine (Biomedical Genetics), Boston University
School of Medicine, 72 East Concord Street, Boston, MA, 02118, USA
| | - Ryan Koesterer
- Department of Medicine (Biomedical Genetics), Boston University
School of Medicine, 72 East Concord Street, Boston, MA, 02118, USA
| | - Laura Almasy
- Texas Biomedical Research Institute, Department of Genetics, P.O.
Box 760549, San Antonio, TX, 78245-0549, USA
| | - Hongyu Zhao
- Department of Genetics, Yale University School of Medicine, 333
Cedar Street, New Haven, CT, 06510, USA
- Department of Biostatistics, Yale University School of Medicine,
333 Cedar Street, New Haven, CT, 06510, USA
| | - Henry R. Kranzler
- Department of Psychiatry, University of Pennsylvania Perelman
School of Medicine, Treatment Research Center, 3900 Chestnut Street, Philadelphia,
PA 19104, USA
- VISN 4 MIRECC, Philadelphia VA Medical Center, 3900 Woodland
Avenue, Philadelphia, PA, 19104, USA
| | - Lindsay A. Farrer
- Department of Psychiatry, VA CT Healthcare Center, 950 Campbell
Avenue, West Haven, CT, 06516, USA
- Department of Neurology, Boston University School of Medicine, 72
East Concord Street, Boston, MA, 02118, USA
- Department of Ophthalmology, Boston University School of Medicine,
72 East Concord Street, Boston, MA, 02118, USA
- Department of Genetics and Genomics, Boston University School of
Medicine, 72 East Concord Street, Boston, MA, 02118, USA
- Department of Epidemiology and Biostatistics, Boston University
School of Public Health, 715 Albany Street, Boston, MA, 02118, USA
| | - Brion S. Maher
- Department of Mental Health, Johns Hopkins Bloomberg School of
Public Health, 624 N. Broadway, 8th Floor, Baltimore, MD, 21205, USA
| | - Carol A. Prescott
- Department of Psychology, University of Southern California, SGM
501, 3620 South McClintock Ave., Los Angeles, CA, 90089-1061, USA
| | - Danielle M. Dick
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
- Department of Human & Molecular Genetics, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - Silviu A. Bacanu
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
| | - Laura D. Mathies
- Department of Pharmacology & Toxicology, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - Andrew G. Davies
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Pharmacology & Toxicology, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - Vladimir I. Vladimirov
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
- Lieber Institute for Brain Development, Johns Hopkins University,
855 North Wolfe Street Suite 300, Baltimore, MD, 21205, USA
- Center for Biomarker Research and Personalized Medicine, School of
Pharmacy, PO Box 980533, Virginia Commonwealth University, Richmond, VA 23298-0533,
USA
| | - Mike Grotewiel
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Human & Molecular Genetics, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - M. Scott Bowers
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
- Department of Pharmacology & Toxicology, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - Jill C. Bettinger
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Pharmacology & Toxicology, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - Bradley T. Webb
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
| | - Michael F. Miles
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Human & Molecular Genetics, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Pharmacology & Toxicology, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - Kenneth S. Kendler
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
- Department of Human & Molecular Genetics, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
| | - Brien P. Riley
- Virginia Commonwealth University Alcohol Research Center, PO Box
980424, Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
- Department of Psychiatry, PO Box 980424, Virginia Commonwealth
University, Richmond, VA, 23298-0424, USA
- Department of Human & Molecular Genetics, PO Box 980424,
Virginia Commonwealth University, Richmond, VA, 23298-0424, USA
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9
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Gioia DA, McCool B. Strain-Dependent Effects of Acute Alcohol on Synaptic Vesicle Recycling and Post-Tetanic Potentiation in Medial Glutamate Inputs to the Mouse Basolateral Amygdala. Alcohol Clin Exp Res 2017; 41:735-746. [PMID: 28118494 DOI: 10.1111/acer.13343] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 01/14/2017] [Indexed: 12/31/2022]
Abstract
BACKGROUND Inbred mouse strains are differentially sensitive to the acute effects of ethanol (EtOH) and are useful tools for examining how unique genomes differentially affect alcohol-related behaviors and physiology. DBA/2J mice have been shown to be sensitive to the acute anxiolytic effects of alcohol as well as the anxiogenic effects of withdrawal from chronic alcohol exposure, while B6 mice are resistant to both. Considering that the basolateral amygdala (BLA) is an important brain region for the acute and chronic effects of EtOH on fear and anxiety related behaviors, we hypothesized that there would be strain-dependent differences in the acute effects of EtOH in BLA slices. METHODS We utilized patch clamp electrophysiology in BLA coronal slices from 4 inbred mouse strains (A/J, BALBcJ, C57BL/6J, and DBA/2J) to examine how genetic background influences acute EtOH effects on synaptic vesicle recycling and post-tetanic potentiation (PTP) in response to low (2 Hz)- and high (40 Hz)-frequency stimulation. RESULTS We found that EtOH inhibited synaptic vesicle recycling in a strain- and stimulation frequency-dependent manner. Vesicle recycling in DBA/2J and BALBcJ cells was inhibited by acute EtOH during both low- and high-frequency stimulation, while recycling measured from A/J cells was sensitive only during high-frequency stimulation. Recycling at C57BL/6J synapses was insensitive to EtOH regardless of stimulation frequency. We additionally found that cells from DBA/2J and BALBcJ mice were sensitive to EtOH-mediated inhibition of PTP. CONCLUSIONS Acute EtOH application inhibited vesicle recycling and PTP at glutamatergic synapses in both a strain- and frequency-dependent fashion. Several presynaptic proteins that contribute to synaptic vesicle priming in addition to PTP have been implicated in alcohol-related behaviors, including Munc13, Munc18, and RIM proteins, making them potential candidates for the molecular mechanism controlling these effects.
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Affiliation(s)
- Dominic A Gioia
- Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Brian McCool
- Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina
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10
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Gavin DP, Kusumo H, Zhang H, Guidotti A, Pandey SC. Role of Growth Arrest and DNA Damage-Inducible, Beta in Alcohol-Drinking Behaviors. Alcohol Clin Exp Res 2016; 40:263-72. [PMID: 26842245 DOI: 10.1111/acer.12965] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/13/2015] [Indexed: 12/26/2022]
Abstract
BACKGROUND The contribution of epigenetic factors, such as histone acetylation and DNA methylation, to the regulation of alcohol-drinking behavior has been increasingly recognized over the last several years. GADD45b is a protein demonstrated to be involved in DNA demethylation at neurotrophic factor gene promoters, including at brain-derived neurotrophic factor (Bdnf) which has been highly implicated in alcohol-drinking behavior. METHODS DNA methyltransferase-1 (Dnmt1), 3a, and 3b, and Gadd45a, b, and g mRNA were measured in the nucleus accumbens (NAc) and ventral tegmental areas of high ethanol (EtOH) consuming C57BL/6J (C57) and low alcohol consuming DBA/2J (DBA) mice using quantitative reverse transcriptase polymerase chain reaction (PCR). In the NAc, GADD45b protein was measured via immunohistochemistry and Bdnf9a mRNA using in situ PCR. Bdnf9a promoter histone H3 acetylated at lysines 9 and 14 (H3K9,K14ac) was measured using chromatin immunoprecipitation, and 5-methylcytosine (5MC) and 5-hydroxymethylcytosine (5HMC) using methylated DNA immunoprecipitation. Alcohol-drinking behavior was evaluated in Gadd45b haplodeficient (+/-) and null mice (-/-) utilizing drinking-in-the-dark (DID) and 2-bottle free-choice paradigms. RESULTS C57 mice had lower levels of Gadd45b and g mRNA and GADD45b protein in the NAc relative to the DBA strain. C57 mice had lower NAc shell Bdnf9a mRNA levels, Bdnf9a promoter H3K9,K14ac, and higher Bdnf9a promoter 5HMC and 5MC. Acute EtOH increased GADD45b protein, Bdnf9a mRNA, and histone acetylation and decreased 5HMC in C57 mice. Gadd45b +/- mice displayed higher drinking behavior relative to wild-type littermates in both DID and 2-bottle free-choice paradigms. CONCLUSIONS These data indicate the importance of the DNA demethylation pathway and its interactions with histone posttranslational modifications in alcohol-drinking behavior. Further, we suggest that lower DNA demethylation protein GADD45b levels may affect Bdnf expression possibly leading to altered alcohol-drinking behavior.
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Affiliation(s)
- David P Gavin
- Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois.,Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois
| | - Handojo Kusumo
- Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois.,Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois
| | - Huaibo Zhang
- Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois.,Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois
| | - Alessandro Guidotti
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois
| | - Subhash C Pandey
- Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois.,Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois
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11
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Johnson JR, Rajamanoharan D, McCue HV, Rankin K, Barclay JW. Small Heat Shock Proteins Are Novel Common Determinants of Alcohol and Nicotine Sensitivity in Caenorhabditis elegans. Genetics 2016; 202:1013-27. [PMID: 26773049 PMCID: PMC4788107 DOI: 10.1534/genetics.115.185025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 01/11/2016] [Indexed: 12/26/2022] Open
Abstract
Addiction to drugs is strongly determined by multiple genetic factors. Alcohol and nicotine produce distinct pharmacological effects within the nervous system through discrete molecular targets; yet, data from family and twin analyses support the existence of common genetic factors for addiction in general. The mechanisms underlying addiction, however, are poorly described and common genetic factors for alcohol and nicotine remain unidentified. We investigated the role that the heat shock transcription factor, HSF-1, and its downstream effectors played as common genetic modulators of sensitivity to addictive substances. Using Caenorhabditis elegans, an exemplary model organism with substance dose-dependent responses similar to mammals, we demonstrate that HSF-1 altered sensitivity to both alcohol and nicotine. Using a combination of a targeted RNAi screen of downstream factors and transgenic approaches we identified that these effects were contingent upon the constitutive neuronal expression of HSP-16.48, a small heat shock protein (HSP) homolog of human α-crystallin. Furthermore we demonstrated that the function of HSP-16.48 in drug sensitivity surprisingly was independent of chaperone activity during the heat shock stress response. Instead we identified a distinct domain within the N-terminal region of the HSP-16.48 protein that specified its function in comparison to related small HSPs. Our findings establish and characterize a novel genetic determinant underlying sensitivity to diverse addictive substances.
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Affiliation(s)
- James R Johnson
- The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - Dayani Rajamanoharan
- The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - Hannah V McCue
- The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - Kim Rankin
- The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - Jeff W Barclay
- The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, United Kingdom
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12
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Mayfield J, Arends MA, Harris RA, Blednov YA. Genes and Alcohol Consumption: Studies with Mutant Mice. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 126:293-355. [PMID: 27055617 PMCID: PMC5302130 DOI: 10.1016/bs.irn.2016.02.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this chapter, we review the effects of global null mutant and overexpressing transgenic mouse lines on voluntary self-administration of alcohol. We examine approximately 200 publications pertaining to the effects of 155 mouse genes on alcohol consumption in different drinking models. The targeted genes vary in function and include neurotransmitter, ion channel, neuroimmune, and neuropeptide signaling systems. The alcohol self-administration models include operant conditioning, two- and four-bottle choice continuous and intermittent access, drinking in the dark limited access, chronic intermittent ethanol, and scheduled high alcohol consumption tests. Comparisons of different drinking models using the same mutant mice are potentially the most informative, and we will highlight those examples. More mutants have been tested for continuous two-bottle choice consumption than any other test; of the 137 mouse genes examined using this model, 97 (72%) altered drinking in at least one sex. Overall, the effects of genetic manipulations on alcohol drinking often depend on the sex of the mice, alcohol concentration and time of access, genetic background, as well as the drinking test.
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Affiliation(s)
- J Mayfield
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, United States
| | - M A Arends
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, United States
| | - R A Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, United States.
| | - Y A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, United States
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13
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Caenorhabditis elegans as a Model to Study the Molecular and Genetic Mechanisms of Drug Addiction. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 137:229-52. [PMID: 26810004 DOI: 10.1016/bs.pmbts.2015.10.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Drug addiction takes a massive toll on society. Novel animal models are needed to test new treatments and understand the basic mechanisms underlying addiction. Rodent models have identified the neurocircuitry involved in addictive behavior and indicate that rodents possess some of the same neurobiologic mechanisms that mediate addiction in humans. Recent studies indicate that addiction is mechanistically and phylogenetically ancient and many mechanisms that underlie human addiction are also present in invertebrates. The nematode Caenorhabditis elegans has conserved neurobiologic systems with powerful molecular and genetic tools and a rapid rate of development that enables cost-effective translational discovery. Emerging evidence suggests that C. elegans is an excellent model to identify molecular mechanisms that mediate drug-induced behavior and potential targets for medications development for various addictive compounds. C. elegans emit many behaviors that can be easily quantitated including some that involve interactions with the environment. Ethanol (EtOH) is the best-studied drug-of-abuse in C. elegans and at least 50 different genes/targets have been identified as mediating EtOH's effects and polymorphisms in some orthologs in humans are associated with alcohol use disorders. C. elegans has also been shown to display dopamine and cholinergic system-dependent attraction to nicotine and demonstrate preference for cues previously associated with nicotine. Cocaine and methamphetamine have been found to produce dopamine-dependent reward-like behaviors in C. elegans. These behavioral tests in combination with genetic/molecular manipulations have led to the identification of dozens of target genes/systems in C. elegans that mediate drug effects. The one target/gene identified as essential for drug-induced behavioral responses across all drugs of abuse was the cat-2 gene coding for tyrosine hydroxylase, which is consistent with the role of dopamine neurotransmission in human addiction. Overall, C. elegans can be used to model aspects of drug addiction and identify systems and molecular mechanisms that mediate drug effects. The findings are surprisingly consistent with analogous findings in higher-level organisms. Further, model refinement is warranted to improve model validity and increase utility for medications development.
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14
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Grotewiel M, Bettinger JC. Drosophila and Caenorhabditis elegans as Discovery Platforms for Genes Involved in Human Alcohol Use Disorder. Alcohol Clin Exp Res 2015; 39:1292-311. [PMID: 26173477 PMCID: PMC4656040 DOI: 10.1111/acer.12785] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 05/18/2015] [Indexed: 01/08/2023]
Abstract
BACKGROUND Despite the profound clinical significance and strong heritability of alcohol use disorder (AUD), we do not yet have a comprehensive understanding of the naturally occurring genetic variance within the human genome that drives its development. This lack of understanding is likely to be due in part to the large phenotypic and genetic heterogeneities that underlie human AUD. As a complement to genetic studies in humans, many laboratories are using the invertebrate model organisms (iMOs) Drosophila melanogaster (fruit fly) and Caenorhabditis elegans (nematode worm) to identify genetic mechanisms that influence the effects of alcohol (ethanol) on behavior. While these extremely powerful models have identified many genes that influence the behavioral responses to alcohol, in most cases it has remained unclear whether results from behavioral-genetic studies in iMOs are directly applicable to understanding the genetic basis of human AUD. METHODS In this review, we critically evaluate the utility of the fly and worm models for identifying genes that influence AUD in humans. RESULTS Based on results published through early 2015, studies in flies and worms have identified 91 and 50 genes, respectively, that influence 1 or more aspects of behavioral responses to alcohol. Collectively, these fly and worm genes correspond to 293 orthologous genes in humans. Intriguingly, 51 of these 293 human genes have been implicated in AUD by at least 1 study in human populations. CONCLUSIONS Our analyses strongly suggest that the Drosophila and C. elegans models have considerable utility for identifying orthologs of genes that influence human AUD.
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Affiliation(s)
- Mike Grotewiel
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia
- Virginia Commonwealth University Alcohol Research Center, Richmond, Virginia
| | - Jill C Bettinger
- Department of Pharmacology and Toxicology , Virginia Commonwealth University, Richmond, Virginia
- Virginia Commonwealth University Alcohol Research Center, Richmond, Virginia
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15
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Davies AG, Blackwell GG, Raabe RC, Bettinger JC. An Assay for Measuring the Effects of Ethanol on the Locomotion Speed of Caenorhabditis elegans. J Vis Exp 2015:52681. [PMID: 25938273 PMCID: PMC4476067 DOI: 10.3791/52681] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Alcohol use disorders are a significant public health concern, for which there are few effective treatment strategies. One difficulty that has delayed the development of more effective treatments is the relative lack of understanding of the molecular underpinnings of the effects of ethanol on behavior. The nematode, Caenorhabditis elegans (C. elegans), provides a useful model in which to generate and test hypotheses about the molecular effects of ethanol. Here, we describe an assay that has been developed and used to examine the roles of particular genes and environmental factors in behavioral responses to ethanol, in which locomotion is the behavioral output. Ethanol dose-dependently causes an acute depression of crawling on an agar surface. The effects are dynamic; animals exposed to a high concentration demonstrate an initial strong depression of crawling, referred to here as initial sensitivity, and then partially recover locomotion speed despite the continued presence of the drug. This ethanol-induced behavioral plasticity is referred to here as the development of acute functional tolerance. This assay has been used to demonstrate that these two phenotypes are distinct and genetically separable. The straightforward locomotion assay described here is suitable for examining the effects of both genetic and environmental manipulations on these acute behavioral responses to ethanol in C. elegans.
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Affiliation(s)
- Andrew G Davies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University; VCU Alcohol Research Center, Virginia Commonwealth University
| | - GinaMari G Blackwell
- Department of Pharmacology and Toxicology, Virginia Commonwealth University; VCU Alcohol Research Center, Virginia Commonwealth University
| | - Richard C Raabe
- Department of Pharmacology and Toxicology, Virginia Commonwealth University
| | - Jill C Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University; VCU Alcohol Research Center, Virginia Commonwealth University;
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16
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SWI/SNF chromatin remodeling regulates alcohol response behaviors in Caenorhabditis elegans and is associated with alcohol dependence in humans. Proc Natl Acad Sci U S A 2015; 112:3032-7. [PMID: 25713357 DOI: 10.1073/pnas.1413451112] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Alcohol abuse is a widespread and serious problem. Understanding the factors that influence the likelihood of abuse is important for the development of effective therapies. There are both genetic and environmental influences on the development of abuse, but it has been difficult to identify specific liability factors, in part because of both the complex genetic architecture of liability and the influences of environmental stimuli on the expression of that genetic liability. Epigenetic modification of gene expression can underlie both genetic and environmentally sensitive variation in expression, and epigenetic regulation has been implicated in the progression to addiction. Here, we identify a role for the switching defective/sucrose nonfermenting (SWI/SNF) chromatin-remodeling complex in regulating the behavioral response to alcohol in the nematode Caenorhabditis elegans. We found that SWI/SNF components are required in adults for the normal behavioral response to ethanol and that different SWI/SNF complexes regulate different aspects of the acute response to ethanol. We showed that the SWI/SNF subunits SWSN-9 and SWSN-7 are required in neurons and muscle for the development of acute functional tolerance to ethanol. Examination of the members of the SWI/SNF complex for association with a diagnosis of alcohol dependence in a human population identified allelic variation in a member of the SWI/SNF complex, suggesting that variation in the regulation of SWI/SNF targets may influence the propensity to develop abuse disorders. Together, these data strongly implicate the chromatin remodeling associated with SWI/SNF complex members in the behavioral responses to alcohol across phyla.
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17
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A novel cholinergic action of alcohol and the development of tolerance to that effect in Caenorhabditis elegans. Genetics 2014; 199:135-49. [PMID: 25342716 DOI: 10.1534/genetics.114.171884] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Understanding the genes and mechanisms involved in acute alcohol responses has the potential to allow us to predict an individual's predisposition to developing an alcohol use disorder. To better understand the molecular pathways involved in the activating effects of alcohol and the acute functional tolerance that can develop to such effects, we characterized a novel ethanol-induced hypercontraction response displayed by Caenorhabditis elegans. We compared body size of animals prior to and during ethanol treatment and showed that acute exposure to ethanol produced a concentration-dependent decrease in size followed by recovery to their untreated size by 40 min despite continuous treatment. An increase in cholinergic signaling, leading to muscle hypercontraction, is implicated in this effect because pretreatment with mecamylamine, a nicotinic acetylcholine receptor (nAChR) antagonist, blocked ethanol-induced hypercontraction, as did mutations causing defects in cholinergic signaling (cha-1 and unc-17). Analysis of mutations affecting specific subunits of nAChRs excluded a role for the ACR-2R, the ACR-16R, and the levamisole-sensitive AChR and indicated that this excitation effect is dependent on an uncharacterized nAChR that contains the UNC-63 α-subunit. We performed a forward genetic screen and identified eg200, a mutation that affects a conserved glycine in EAT-6, the α-subunit of the Na(+)/K(+) ATPase. The eat-6(eg200) mutant fails to develop tolerance to ethanol-induced hypercontraction and remains contracted for at least 3 hr of continuous ethanol exposure. These data suggest that cholinergic signaling through a specific α-subunit-containing nAChR is involved in ethanol-induced excitation and that tolerance to this ethanol effect is modulated by Na(+)/K(+) ATPase function.
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18
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Conserved single residue in the BK potassium channel required for activation by alcohol and intoxication in C. elegans. J Neurosci 2014; 34:9562-73. [PMID: 25031399 DOI: 10.1523/jneurosci.0838-14.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Alcohol directly modulates the BK potassium channel to alter behaviors in species ranging from invertebrates to humans. In the nematode Caenorhabditis elegans, mutations that eliminate the BK channel, SLO-1, convey dramatic resistance to intoxication by ethanol. We hypothesized that certain conserved amino acids are critical for ethanol modulation, but not for basal channel function. To identify such residues, we screened C. elegans strains with different missense mutations in the SLO-1 channel. A strain with the SLO-1 missense mutation T381I in the RCK1 domain was highly resistant to intoxication. This mutation did not interfere with other BK channel-dependent behaviors, suggesting that the mutant channel retained normal in vivo function. Knock-in of wild-type versions of the worm or human BK channel rescued intoxication and other BK channel-dependent behaviors in a slo-1-null mutant background. In contrast, knock-in of the worm T381I or equivalent human T352I mutant BK channel selectively rescued BK channel-dependent behaviors while conveying resistance to intoxication. Single-channel patch-clamp recordings confirmed that the human BK channel engineered with the T352I missense mutation was insensitive to activation by ethanol, but otherwise had normal conductance, potassium selectivity, and only subtle differences in voltage dependence. Together, our behavioral and electrophysiological results demonstrate that the T352I mutation selectively disrupts ethanol modulation of the BK channel. The T352I mutation may alter a binding site for ethanol and/or interfere with ethanol-induced conformational changes that are critical for behavioral responses to ethanol.
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19
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Raabe RC, Mathies LD, Davies AG, Bettinger JC. The omega-3 fatty acid eicosapentaenoic acid is required for normal alcohol response behaviors in C. elegans. PLoS One 2014; 9:e105999. [PMID: 25162400 PMCID: PMC4146551 DOI: 10.1371/journal.pone.0105999] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 08/01/2014] [Indexed: 12/18/2022] Open
Abstract
Alcohol addiction is a widespread societal problem, for which there are few treatments. There are significant genetic and environmental influences on abuse liability, and understanding these factors will be important for the identification of susceptible individuals and the development of effective pharmacotherapies. In humans, the level of response to alcohol is strongly predictive of subsequent alcohol abuse. Level of response is a combination of counteracting responses to alcohol, the level of sensitivity to the drug and the degree to which tolerance develops during the drug exposure, called acute functional tolerance. We use the simple and well-characterized nervous system of Caenorhabditis elegans to model the acute behavioral effects of ethanol to identify genetic and environmental factors that influence level of response to ethanol. Given the strong molecular conservation between the neurobiological machinery of worms and humans, cellular-level effects of ethanol are likely to be conserved. Increasingly, variation in long-chain polyunsaturated fatty acid levels has been implicated in complex neurobiological phenotypes in humans, and we recently found that fatty acid levels modify ethanol responses in worms. Here, we report that 1) eicosapentaenoic acid, an omega-3 polyunsaturated fatty acid, is required for the development of acute functional tolerance, 2) dietary supplementation of eicosapentaenoic acid is sufficient for acute tolerance, and 3) dietary eicosapentaenoic acid can alter the wild-type response to ethanol. These results suggest that genetic variation influencing long-chain polyunsaturated fatty acid levels may be important abuse liability loci, and that dietary polyunsaturated fatty acids may be an important environmental modulator of the behavioral response to ethanol.
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Affiliation(s)
- Richard C. Raabe
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Laura D. Mathies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Andrew G. Davies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- VCU-Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Jill C. Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- VCU-Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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Dwyer DS, Aamodt E, Cohen B, Buttner EA. Drug elucidation: invertebrate genetics sheds new light on the molecular targets of CNS drugs. Front Pharmacol 2014; 5:177. [PMID: 25120487 PMCID: PMC4112795 DOI: 10.3389/fphar.2014.00177] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 07/09/2014] [Indexed: 02/02/2023] Open
Abstract
Many important drugs approved to treat common human diseases were discovered by serendipity, without a firm understanding of their modes of action. As a result, the side effects and interactions of these medications are often unpredictable, and there is limited guidance for improving the design of next-generation drugs. Here, we review the innovative use of simple model organisms, especially Caenorhabditis elegans, to gain fresh insights into the complex biological effects of approved CNS medications. Whereas drug discovery involves the identification of new drug targets and lead compounds/biologics, and drug development spans preclinical testing to FDA approval, drug elucidation refers to the process of understanding the mechanisms of action of marketed drugs by studying their novel effects in model organisms. Drug elucidation studies have revealed new pathways affected by antipsychotic drugs, e.g., the insulin signaling pathway, a trace amine receptor and a nicotinic acetylcholine receptor. Similarly, novel targets of antidepressant drugs and lithium have been identified in C. elegans, including lipid-binding/transport proteins and the SGK-1 signaling pathway, respectively. Elucidation of the mode of action of anesthetic agents has shown that anesthesia can involve mitochondrial targets, leak currents, and gap junctions. The general approach reviewed in this article has advanced our knowledge about important drugs for CNS disorders and can guide future drug discovery efforts.
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Affiliation(s)
- Donard S. Dwyer
- Department of Psychiatry–Department of Pharmacology, Toxicology and Neuroscience, Louisiana State University Health Sciences Center-ShreveportShreveport, LA, USA
| | - Eric Aamodt
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center-ShreveportShreveport, LA, USA
| | - Bruce Cohen
- Department of Psychiatry, Harvard Medical SchoolBoston, MA, USA
- Mailman Research Center, McLean HospitalBelmont, MA, USA
| | - Edgar A. Buttner
- Mailman Research Center, McLean HospitalBelmont, MA, USA
- Department of Neurology–Department of Psychiatry, McLean Hospital, Harvard Medical SchoolBelmont, MA, USA
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Nematodes feel a craving--using Caenorhabditis elegans as a model to study alcohol addiction. Neurosci Bull 2014; 30:595-600. [PMID: 25008572 DOI: 10.1007/s12264-014-1451-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 05/12/2014] [Indexed: 10/25/2022] Open
Abstract
Alcohol is the most frequently-used addictive drug. However, the mechanism by which its consumption leads to addiction remains largely elusive. Given the conservation of behavioral reactions to alcohol, Caenorhabitis elegans (C. elegans) has been effectively used as a model system to investigate the relevant molecular targets and pathways mediating these responses. In this article, we review the roles of BK channels (also called SLO-1), the lipid microenvironment, receptors, the synaptic machinery, and neurotransmitters in both the acute and chronic effects of alcohol. We provide an overview of the genes and mechanisms involved in alcoholismrelated behaviors in C. elegans.
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Johnson JR, Kashyap S, Rankin K, Barclay JW. Rab-3 and unc-18 interactions in alcohol sensitivity are distinct from synaptic transmission. PLoS One 2013; 8:e81117. [PMID: 24244732 PMCID: PMC3828271 DOI: 10.1371/journal.pone.0081117] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 10/18/2013] [Indexed: 01/31/2023] Open
Abstract
The molecular mechanisms underlying sensitivity to alcohol are incompletely understood. Recent research has highlighted the involvement of two presynaptic proteins, Munc18 and Rab3. We have previously characterised biochemically a number of specific Munc18 point mutations including an E466K mutation that augments a direct Rab3 interaction. Here the phenotypes of this and other Munc18 mutations were assessed in alcohol sensitivity and exocytosis using Caenorhabditis elegans. We found that expressing the orthologous E466K mutation (unc-18 E465K) enhanced alcohol sensitivity. This enhancement in sensitivity was surprisingly independent of rab-3. In contrast unc-18 R39C, which decreases syntaxin binding, enhanced sensitivity to alcohol in a manner requiring rab-3. Finally, overexpression of R39C could suppress partially the reduction in neurotransmitter release in rab-3 mutant worms, whereas wild-type or E465K mutants showed no rescue. These data indicate that the epistatic interactions between unc-18 and rab-3 in modulating sensitivity to alcohol are distinct from interactions affecting neurotransmitter release.
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Affiliation(s)
- James R. Johnson
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Sudhanva Kashyap
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Kim Rankin
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Jeff W. Barclay
- Department of Cellular and Molecular Physiology, The Physiological Laboratory, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
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Mustard JA. The buzz on caffeine in invertebrates: effects on behavior and molecular mechanisms. Cell Mol Life Sci 2013; 71:1375-82. [PMID: 24162934 DOI: 10.1007/s00018-013-1497-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 09/12/2013] [Accepted: 10/14/2013] [Indexed: 10/26/2022]
Abstract
A number of recent studies from as diverse fields as plant-pollinator interactions, analyses of caffeine as an environmental pollutant, and the ability of caffeine to provide protection against neurodegenerative diseases have generated interest in understanding the actions of caffeine in invertebrates. This review summarizes what is currently known about the effects of caffeine on behavior and its molecular mechanisms in invertebrates. Caffeine appears to have similar effects on locomotion and sleep in both invertebrates and mammals. Furthermore, as in mammals, caffeine appears to have complex effects on learning and memory. However, the underlying mechanisms for these effects may differ between invertebrates and vertebrates. While caffeine's ability to cause release of intracellular calcium stores via ryanodine receptors and its actions as a phosphodiesterase inhibitor have been clearly established in invertebrates, its ability to interact with invertebrate adenosine receptors remains an important open question. Initial studies in insects and mollusks suggest an interaction between caffeine and the dopamine signaling pathway; more work needs to be done to understand the mechanisms by which caffeine influences signaling via biogenic amines. As of yet, little is known about whether other actions of caffeine in vertebrates, such as its effects on GABAA and glycine receptors, are conserved. Furthermore, the pharmacokinetics of caffeine remains to be elucidated. Overall behavioral responses to caffeine appear to be conserved amongst organisms; however, we are just beginning to understand the mechanisms underlying its effects across animal phyla.
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Affiliation(s)
- Julie A Mustard
- School of Life Sciences, Arizona State University, Tempe, AZ, 85287, USA,
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Effect of chronic ethanol treatment on μ-opioid receptor function, interacting proteins and morphine-induced place preference. Psychopharmacology (Berl) 2013; 228:207-15. [PMID: 23430162 DOI: 10.1007/s00213-013-3023-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Accepted: 02/05/2013] [Indexed: 01/03/2023]
Abstract
RATIONALE Both the acute and chronic consumption of ethanol have been reported to modify several molecular events in the central nervous system, and the endogenous μ-opioid receptor system is involved in the reinforcing/rewarding effects of ethanol. OBJECTIVES The present study was designed to clarify the effects of chronic ethanol treatment on cellular processes involving μ-opioid receptor and the development of morphine-induced rewarding effects. METHODS Male C57BL/6J mice were continuously treated with a liquid diet containing 3.0 w/v ethanol. The direct involvement of μ-opioid receptor functions in the activation of G-proteins and changes in protein levels in the lower midbrain of mice after chronic treatment with ethanol were investigated by a [(35)S] GTPγS binding assay and Western blotting, respectively. The rewarding effects of morphine (5 mg/kg) under treatment with ethanol were measured by the conditioned place preference paradigm. RESULTS The function of μ-opioid receptor was increased by treatment with ethanol in the lower midbrain using [(35)S] GTPγS binding assay. Furthermore, the GRK2 protein level was significantly increased by treatment with ethanol. Chronic treatment with ethanol enhanced the rewarding effects of morphine. On the other hand, this enhancement of the rewarding effects of morphine by ethanol treatment was significantly inhibited by the GRK2 inhibitor β-adrenergic receptor kinase 1 inhibitor. CONCLUSIONS The present study demonstrated that chronic treatment with ethanol enhanced the rewarding effects of morphine by up-regulating functional changes in μ-opioid receptor, mediated by GRK2.
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Kapfhamer D, King I, Zou ME, Lim JP, Heberlein U, Wolf FW. JNK pathway activation is controlled by Tao/TAOK3 to modulate ethanol sensitivity. PLoS One 2012; 7:e50594. [PMID: 23227189 PMCID: PMC3515618 DOI: 10.1371/journal.pone.0050594] [Citation(s) in RCA: 30] [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: 07/09/2012] [Accepted: 10/25/2012] [Indexed: 02/08/2023] Open
Abstract
Neuronal signal transduction by the JNK MAP kinase pathway is altered by a broad array of stimuli including exposure to the widely abused drug ethanol, but the behavioral relevance and the regulation of JNK signaling is unclear. Here we demonstrate that JNK signaling functions downstream of the Sterile20 kinase family gene tao/Taok3 to regulate the behavioral effects of acute ethanol exposure in both the fruit fly Drosophila and mice. In flies tao is required in neurons to promote sensitivity to the locomotor stimulant effects of acute ethanol exposure and to establish specific brain structures. Reduced expression of key JNK pathway genes substantially rescued the structural and behavioral phenotypes of tao mutants. Decreasing and increasing JNK pathway activity resulted in increased and decreased sensitivity to the locomotor stimulant properties of acute ethanol exposure, respectively. Further, JNK expression in a limited pattern of neurons that included brain regions implicated in ethanol responses was sufficient to restore normal behavior. Mice heterozygous for a disrupted allele of the homologous Taok3 gene (Taok3Gt) were resistant to the acute sedative effects of ethanol. JNK activity was constitutively increased in brains of Taok3Gt/+ mice, and acute induction of phospho-JNK in brain tissue by ethanol was occluded in Taok3Gt/+ mice. Finally, acute administration of a JNK inhibitor conferred resistance to the sedative effects of ethanol in wild-type but not Taok3Gt/+ mice. Taken together, these data support a role of a TAO/TAOK3-JNK neuronal signaling pathway in regulating sensitivity to acute ethanol exposure in flies and in mice.
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Affiliation(s)
- David Kapfhamer
- The Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
- * E-mail: (DK); (FWW)
| | - Ian King
- Department of Anatomy, Program in Neuroscience, University of California San Francisco, San Francisco, California, United States of America
| | - Mimi E. Zou
- The Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
| | - Jana P. Lim
- The Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
| | - Ulrike Heberlein
- The Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
- Department of Anatomy, Program in Neuroscience, University of California San Francisco, San Francisco, California, United States of America
| | - Fred W. Wolf
- The Ernest Gallo Clinic and Research Center, University of California San Francisco, Emeryville, California, United States of America
- * E-mail: (DK); (FWW)
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26
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Neurotransmitter release mechanisms studied in Caenorhabditis elegans. Cell Calcium 2012; 52:289-95. [DOI: 10.1016/j.ceca.2012.03.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 03/19/2012] [Accepted: 03/25/2012] [Indexed: 01/15/2023]
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Kapfhamer D, Taylor S, Zou ME, Lim JP, Kharazia V, Heberlein U. Taok2 controls behavioral response to ethanol in mice. GENES BRAIN AND BEHAVIOR 2012; 12:87-97. [PMID: 22883308 DOI: 10.1111/j.1601-183x.2012.00834.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 05/30/2012] [Accepted: 08/02/2012] [Indexed: 01/27/2023]
Abstract
Despite recent advances in the understanding of ethanol's biological action, many of the molecular targets of ethanol and mechanisms behind ethanol's effect on behavior remain poorly understood. In an effort to identify novel genes, the products of which regulate behavioral responses to ethanol, we recently identified a mutation in the dtao gene that confers resistance to the locomotor stimulating effect of ethanol in Drosophila. dtao encodes a member of the Ste20 family of serine/threonine kinases implicated in MAP kinase signaling pathways. In this study, we report that conditional ablation of the mouse dtao homolog, Taok2, constitutively and specifically in the nervous system, results in strain-specific and overlapping alterations in ethanol-dependent behaviors. These data suggest a functional conservation of dtao and Taok2 in mediating ethanol's biological action and identify Taok2 as a putative candidate gene for ethanol use disorders in humans.
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Affiliation(s)
- D Kapfhamer
- The Ernest Gallo Clinic and Research Center, University of California at San Francisco, Emeryville, CA 94608, USA.
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Wolen AR, Phillips CA, Langston MA, Putman AH, Vorster PJ, Bruce NA, York TP, Williams RW, Miles MF. Genetic dissection of acute ethanol responsive gene networks in prefrontal cortex: functional and mechanistic implications. PLoS One 2012; 7:e33575. [PMID: 22511924 PMCID: PMC3325236 DOI: 10.1371/journal.pone.0033575] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 02/15/2012] [Indexed: 01/21/2023] Open
Abstract
Background Individual differences in initial sensitivity to ethanol are strongly related to the heritable risk of alcoholism in humans. To elucidate key molecular networks that modulate ethanol sensitivity we performed the first systems genetics analysis of ethanol-responsive gene expression in brain regions of the mesocorticolimbic reward circuit (prefrontal cortex, nucleus accumbens, and ventral midbrain) across a highly diverse family of 27 isogenic mouse strains (BXD panel) before and after treatment with ethanol. Results Acute ethanol altered the expression of ∼2,750 genes in one or more regions and 400 transcripts were jointly modulated in all three. Ethanol-responsive gene networks were extracted with a powerful graph theoretical method that efficiently summarized ethanol's effects. These networks correlated with acute behavioral responses to ethanol and other drugs of abuse. As predicted, networks were heavily populated by genes controlling synaptic transmission and neuroplasticity. Several of the most densely interconnected network hubs, including Kcnma1 and Gsk3β, are known to influence behavioral or physiological responses to ethanol, validating our overall approach. Other major hub genes like Grm3, Pten and Nrg3 represent novel targets of ethanol effects. Networks were under strong genetic control by variants that we mapped to a small number of chromosomal loci. Using a novel combination of genetic, bioinformatic and network-based approaches, we identified high priority cis-regulatory candidate genes, including Scn1b, Gria1, Sncb and Nell2. Conclusions The ethanol-responsive gene networks identified here represent a previously uncharacterized intermediate phenotype between DNA variation and ethanol sensitivity in mice. Networks involved in synaptic transmission were strongly regulated by ethanol and could contribute to behavioral plasticity seen with chronic ethanol. Our novel finding that hub genes and a small number of loci exert major influence over the ethanol response of gene networks could have important implications for future studies regarding the mechanisms and treatment of alcohol use disorders.
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Affiliation(s)
- Aaron R. Wolen
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Charles A. Phillips
- Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Michael A. Langston
- Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Alex H. Putman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Paul J. Vorster
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Nathan A. Bruce
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Timothy P. York
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Robert W. Williams
- Department of Anatomy and Neurobiology, University of Tennessee Health Sciences, Memphis, Tennessee, United States of America
| | - Michael F. Miles
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Neurology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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Alaimo JT, Davis SJ, Song SS, Burnette CR, Grotewiel M, Shelton KL, Pierce-Shimomura JT, Davies AG, Bettinger JC. Ethanol metabolism and osmolarity modify behavioral responses to ethanol in C. elegans. Alcohol Clin Exp Res 2012; 36:1840-50. [PMID: 22486589 DOI: 10.1111/j.1530-0277.2012.01799.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 02/10/2012] [Indexed: 12/29/2022]
Abstract
BACKGROUND Ethanol (EtOH) is metabolized by a 2-step process in which alcohol dehydrogenase (ADH) oxidizes EtOH to acetaldehyde, which is further oxidized to acetate by aldehyde dehydrogenase (ALDH). Although variation in EtOH metabolism in humans strongly influences the propensity to chronically abuse alcohol, few data exist on the behavioral effects of altered EtOH metabolism. Here, we used the nematode Caenorhabditis elegans to directly examine how changes in EtOH metabolism alter behavioral responses to alcohol during an acute exposure. Additionally, we investigated EtOH solution osmolarity as a potential explanation for contrasting published data on C. elegans EtOH sensitivity. METHODS We developed a gas chromatography assay and validated a spectrophotometric method to measure internal EtOH in EtOH-exposed worms. Further, we tested the effects of mutations in ADH and ALDH genes on EtOH tissue accumulation and behavioral sensitivity to the drug. Finally, we tested the effects of EtOH solution osmolarity on behavioral responses and tissue EtOH accumulation. RESULTS Only a small amount of exogenously applied EtOH accumulated in the tissues of C. elegans and consequently their tissue concentrations were similar to those that intoxicate humans. Independent inactivation of an ADH-encoding gene (sodh-1) or an ALDH-encoding gene (alh-6 or alh-13) increased the EtOH concentration in worms and caused hypersensitivity to the acute sedative effects of EtOH on locomotion. We also found that the sensitivity to the depressive effects of EtOH on locomotion is strongly influenced by the osmolarity of the exogenous EtOH solution. CONCLUSIONS Our results indicate that EtOH metabolism via ADH and ALDH has a statistically discernable but surprisingly minor influence on EtOH sedation and internal EtOH accumulation in worms. In contrast, the osmolarity of the medium in which EtOH is delivered to the animals has a more substantial effect on the observed sensitivity to EtOH.
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Affiliation(s)
- Joseph T Alaimo
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
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Davies AG, Friedberg RI, Gupta H, Chan CL, Shelton KL, Bettinger JC. Different genes influence toluene- and ethanol-induced locomotor impairment in C. elegans. Drug Alcohol Depend 2012; 122:47-54. [PMID: 21945072 PMCID: PMC3260412 DOI: 10.1016/j.drugalcdep.2011.08.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 08/12/2011] [Accepted: 08/31/2011] [Indexed: 01/25/2023]
Abstract
BACKGROUND The abused volatile solvent toluene shares many behavioral effects with classic central nervous system depressants such as ethanol. Similarities between toluene and ethanol have also been demonstrated using in vitro electrophysiology. Together, these studies suggest that toluene and ethanol may be acting, at least in part, via common mechanisms. METHODS We used the genetic model, Caenorhabditis elegans, to examine the behavioral effects of toluene in a simple system, and used mutant strains known to have altered responses to other CNS depressants to examine the involvement of those genes in the motor effects induced by toluene. RESULTS Toluene vapor brings about an altered pattern of locomotion in wild-type worms that is visibly distinct from that generated by ethanol. Mutants of the slo-1, rab-3 and unc-64 genes that are resistant to ethanol or the volatile anesthetic halothane show no resistance to toluene. A mutation in the unc-79 gene results in hypersensitivity to ethanol, halothane and toluene indicating a possible convergence of mechanisms of the three compounds. We screened for, and isolated, two mutations that generate resistance to the locomotor depressing effects of toluene and do not alter sensitivity to ethanol. CONCLUSIONS In C. elegans, ethanol and toluene have distinct behavioral effects and minimal overlap in terms of the genes responsible for these effects. These findings demonstrate that the C. elegans model system provides a unique and sensitive means of delineating both the commonalities as well as the differences in the neurochemical effects of classical CNS depressants and abused volatile inhalants.
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Affiliation(s)
- Andrew G. Davies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University Richmond, VA 23298-0613 USA,Department of Psychiatry, Virginia Commonwealth University Richmond, VA 23298-0613 USA,Institute for Drug and Alcohol Studies, Virginia Commonwealth University Richmond, VA 23298-0613 USA,Virginia Commonwealth University – Alcohol Research Center Virginia Commonwealth University Richmond, VA 23298-0613 USA,Corresponding author Andrew G. Davies, Ph.D. Department of Pharmacology and Toxicology Virginia Commonwealth University P.O. Box 980613 Richmond VA, 23298-0613 (804) 828-2068 (w) (804) 828-4794 (fax)
| | - Ryan I. Friedberg
- Department of Pharmacology and Toxicology, Virginia Commonwealth University Richmond, VA 23298-0613 USA
| | - Hersh Gupta
- Department of Pharmacology and Toxicology, Virginia Commonwealth University Richmond, VA 23298-0613 USA
| | - Chung-Lung Chan
- Department of Pharmacology and Toxicology, Virginia Commonwealth University Richmond, VA 23298-0613 USA
| | - Keith L. Shelton
- Department of Pharmacology and Toxicology, Virginia Commonwealth University Richmond, VA 23298-0613 USA,Institute for Drug and Alcohol Studies, Virginia Commonwealth University Richmond, VA 23298-0613 USA
| | - Jill C. Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University Richmond, VA 23298-0613 USA,Department of Psychiatry, Virginia Commonwealth University Richmond, VA 23298-0613 USA,Institute for Drug and Alcohol Studies, Virginia Commonwealth University Richmond, VA 23298-0613 USA,Virginia Commonwealth University – Alcohol Research Center Virginia Commonwealth University Richmond, VA 23298-0613 USA
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Bhandari P, Hill JS, Farris SP, Costin B, Martin I, Chan CL, Alaimo JT, Bettinger JC, Davies AG, Miles MF, Grotewiel M. Chloride intracellular channels modulate acute ethanol behaviors in Drosophila, Caenorhabditis elegans and mice. GENES BRAIN AND BEHAVIOR 2012; 11:387-97. [PMID: 22239914 DOI: 10.1111/j.1601-183x.2012.00765.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Identifying genes that influence behavioral responses to alcohol is critical for understanding the molecular basis of alcoholism and ultimately developing therapeutic interventions for the disease. Using an integrated approach that combined the power of the Drosophila, Caenorhabditis elegans and mouse model systems with bioinformatics analyses, we established a novel, conserved role for chloride intracellular channels (CLICs) in alcohol-related behavior. CLIC proteins might have several biochemical functions including intracellular chloride channel activity, modulation of transforming growth factor (TGF)-β signaling, and regulation of ryanodine receptors and A-kinase anchoring proteins. We initially identified vertebrate Clic4 as a candidate ethanol-responsive gene via bioinformatic analysis of data from published microarray studies of mouse and human ethanol-related genes. We confirmed that Clic4 expression was increased by ethanol treatment in mouse prefrontal cortex and also uncovered a correlation between basal expression of Clic4 in prefrontal cortex and the locomotor activating and sedating properties of ethanol across the BXD mouse genetic reference panel. Furthermore, we found that disruption of the sole Clic Drosophila orthologue significantly blunted sensitivity to alcohol in flies, that mutations in two C. elegans Clic orthologues, exc-4 and exl-1, altered behavioral responses to acute ethanol in worms and that viral-mediated overexpression of Clic4 in mouse brain decreased the sedating properties of ethanol. Together, our studies demonstrate key roles for Clic genes in behavioral responses to acute alcohol in Drosophila, C. elegans and mice.
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Affiliation(s)
- P Bhandari
- Department of Human and Molecular Genetics, Department of Pharmacology and Toxicology, Virginia Commonwealth University Alcohol Research Center, Richmond, VA, USA
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Castro PV, Khare S, Young BD, Clarke SG. Caenorhabditis elegans battling starvation stress: low levels of ethanol prolong lifespan in L1 larvae. PLoS One 2012; 7:e29984. [PMID: 22279556 PMCID: PMC3261173 DOI: 10.1371/journal.pone.0029984] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 12/08/2011] [Indexed: 12/24/2022] Open
Abstract
The nematode Caenorhabditis elegans arrests development at the first larval stage if food is not present upon hatching. Larvae in this stage provide an excellent model for studying stress responses during development. We found that supplementing starved larvae with ethanol markedly extends their lifespan within this L1 diapause. The effects of ethanol-induced lifespan extension can be observed when the ethanol is added to the medium at any time between 0 and 10 days after hatching. The lowest ethanol concentration that extended lifespan was 1 mM (0.005%); higher concentrations to 68 mM (0.4%) did not result in increased survival. In spite of their extended survival, larvae did not progress to the L2 stage. Supplementing starved cultures with n-propanol and n-butanol also extended lifespan, but methanol and isopropanol had no measurable effect. Mass spectrometry analysis of nematode fatty acids and amino acids revealed that L1 larvae can incorporate atoms from ethanol into both types of molecules. Based on these data, we suggest that ethanol supplementation may extend the lifespan of L1 larvae by either serving as a carbon and energy source and/or by inducing a stress response.
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Affiliation(s)
- Paola V. Castro
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Shilpi Khare
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Brian D. Young
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California Los Angeles, Los Angeles, California, United States of America
| | - Steven G. Clarke
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Bendena WG, Campbell J, Zara L, Tobe SS, Chin-Sang ID. Select Neuropeptides and their G-Protein Coupled Receptors in Caenorhabditis Elegans and Drosophila Melanogaster. Front Endocrinol (Lausanne) 2012; 3:93. [PMID: 22908006 PMCID: PMC3414713 DOI: 10.3389/fendo.2012.00093] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 07/14/2012] [Indexed: 12/18/2022] Open
Abstract
The G-protein coupled receptor (GPCR) family is comprised of seven transmembrane domain proteins and play important roles in nerve transmission, locomotion, proliferation and development, sensory perception, metabolism, and neuromodulation. GPCR research has been targeted by drug developers as a consequence of the wide variety of critical physiological functions regulated by this protein family. Neuropeptide GPCRs are the least characterized of the GPCR family as genetic systems to characterize their functions have lagged behind GPCR gene discovery. Drosophila melanogaster and Caenorhabditis elegans are genetic model organisms that have proved useful in characterizing neuropeptide GPCRs. The strength of a genetic approach leads to an appreciation of the behavioral plasticity that can result from subtle alterations in GPCRs or regulatory proteins in the pathways that GPCRs control. Many of these invertebrate neuropeptides, GPCRs, and signaling pathway components serve as models for mammalian counterparts as they have conserved sequences and function. This review provides an overview of the methods to match neuropeptides to their cognate receptor and a state of the art account of neuropeptide GPCRs that have been characterized in D. melanogaster and C. elegans and the behaviors that have been uncovered through genetic manipulation.
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Affiliation(s)
- William G. Bendena
- Department of Biology, Queen’s UniversityKingston, ON, Canada
- *Correspondence: William G. Bendena, Department of Biology, Queen’s University, Kingston, ON, Canada K7L 3N6. e-mail:
| | - Jason Campbell
- Department of Biology, Queen’s UniversityKingston, ON, Canada
| | - Lian Zara
- Department of Biology, Queen’s UniversityKingston, ON, Canada
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Wang Y, Tang L, Feng X, Du W, Liu BF. Ethanol interferes with gustatory plasticity in Caenorhabditis elegans. Neurosci Res 2011; 71:341-7. [DOI: 10.1016/j.neures.2011.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 07/25/2011] [Accepted: 08/18/2011] [Indexed: 12/01/2022]
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Wang X, Sliwoski GR, Buttner EA. The relevance of Caenorhabditis elegans genetics for understanding human psychiatric disease. Harv Rev Psychiatry 2011; 19:210-8. [PMID: 21790269 DOI: 10.3109/10673229.2011.599185] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Wolstenholme JT, Warner JA, Capparuccini MI, Archer KJ, Shelton KL, Miles MF. Genomic analysis of individual differences in ethanol drinking: evidence for non-genetic factors in C57BL/6 mice. PLoS One 2011; 6:e21100. [PMID: 21698166 PMCID: PMC3116881 DOI: 10.1371/journal.pone.0021100] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Accepted: 05/20/2011] [Indexed: 01/26/2023] Open
Abstract
Genetic analysis of factors affecting risk to develop excessive ethanol drinking has been extensively studied in humans and animal models for over 20 years. However, little progress has been made in determining molecular mechanisms underlying environmental or non-genetic events contributing to variation in ethanol drinking. Here, we identify persistent and substantial variation in ethanol drinking behavior within an inbred mouse strain and utilize this model to identify gene networks influencing such “non-genetic” variation in ethanol intake. C57BL/6NCrl mice showed persistent inter-individual variation of ethanol intake in a two-bottle choice paradigm over a three-week period, ranging from less than 1 g/kg to over 14 g/kg ethanol in an 18 h interval. Differences in sweet or bitter taste susceptibility or litter effects did not appreciably correlate with ethanol intake variation. Whole genome microarray expression analysis in nucleus accumbens, prefrontal cortex and ventral midbrain region of individual animals identified gene expression patterns correlated with ethanol intake. Results included several gene networks previously implicated in ethanol behaviors, such as glutamate signaling, BDNF and genes involved in synaptic vesicle function. Additionally, genes functioning in epigenetic chromatin or DNA modifications such as acetylation and/or methylation also had expression patterns correlated with ethanol intake. In verification for the significance of the expression findings, we found that a histone deacetylase inhibitor, trichostatin A, caused an increase in 2-bottle ethanol intake. Our results thus implicate specific brain regional gene networks, including chromatin modification factors, as potentially important mechanisms underlying individual variation in ethanol intake.
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Affiliation(s)
- Jennifer T. Wolstenholme
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Jon A. Warner
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Maria I. Capparuccini
- Department of Biostatistics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Kellie J. Archer
- Department of Biostatistics, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Keith L. Shelton
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Michael F. Miles
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Neurology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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Lasek AW, Giorgetti F, Berger KH, Tayor S, Heberlein U. Lmo genes regulate behavioral responses to ethanol in Drosophila melanogaster and the mouse. Alcohol Clin Exp Res 2011; 35:1600-6. [PMID: 21599714 DOI: 10.1111/j.1530-0277.2011.01506.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Previous work from our laboratory demonstrated a role for the Drosophila Lim-only (dLmo) gene in regulating behavioral responses to cocaine. Herein, we examined whether dLmo influences the flies' sensitivity to ethanol's sedating effects. We also investigated whether 1 of the mammalian homologs of dLmo, Lmo3, is involved in behavioral responses to ethanol in mice. METHODS To examine dLmo function in ethanol-induced sedation, mutant flies with reduced or increased dLmo expression were tested using the loss of righting (LOR) assay. To determine whether mouse Lmo3 regulates behavioral responses to ethanol, we generated transgenic mice expressing a short-hairpin RNA targeting Lmo3 for RNA interference-mediated knockdown by lentiviral infection of single cell embryos. Adult founder mice, expressing varying amounts of Lmo3 in the brain, were tested using ethanol loss-of-righting-reflex (LORR) and 2-bottle choice ethanol consumption assays. RESULTS We found that in flies, reduced dLmo activity increased sensitivity to ethanol-induced sedation, whereas increased expression of dLmo led to increased resistance to ethanol-induced sedation. In mice, reduced levels of Lmo3 were correlated with increased sedation time in the LORR test and decreased ethanol consumption in the 2-bottle choice protocol. CONCLUSIONS These data describe a novel and conserved role for Lmo genes in flies and mice in behavioral responses to ethanol. These studies also demonstrate the feasibility of rapidly translating findings from invertebrate systems to mammalian models of alcohol abuse by combining RNA interference in transgenic mice and behavioral testing.
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Affiliation(s)
- Amy W Lasek
- Ernest Gallo Clinic and Research Center, University of California at San Francisco, California, USA.
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Kawli T, He F, Tan MW. It takes nerves to fight infections: insights on neuro-immune interactions from C. elegans. Dis Model Mech 2010; 3:721-31. [PMID: 20829562 PMCID: PMC2965399 DOI: 10.1242/dmm.003871] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The innate immune response is evoked as a consequence of interactions between invading foreign infectious agents and host immune cells. A successful innate immune response is pivotal in maintaining the delicate balance between health and disease; an insufficient response results in infection, whereas an excessive response results in prolonged inflammation and tissue damage. Alterations in the state and function of the nervous system influence the immune response. The nervous system regulates innate immune responses through the release of neurotransmitters, neuropeptides and neurohormones. However, many questions related to the molecular and cellular mechanisms involved, the physiological role of the link between the immune and the nervous system, and the biological significance of neuro-immune interactions remain unresolved. The interactions between the nematode Caenorhabditis elegans and its pathogens provide insights into mechanisms of neuroendocrine regulation of immunity and address many outstanding issues related to neuro-immune interactions.
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Affiliation(s)
- Trupti Kawli
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 394305, USA
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Wang Y, Wang J, Du W, Feng XJ, Liu BF. Identification of the neuronal effects of ethanol on C. elegans by in vivo fluorescence imaging on a microfluidic chip. Anal Bioanal Chem 2010; 399:3475-81. [DOI: 10.1007/s00216-010-4148-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2010] [Revised: 08/18/2010] [Accepted: 08/18/2010] [Indexed: 11/24/2022]
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A differential role for neuropeptides in acute and chronic adaptive responses to alcohol: behavioural and genetic analysis in Caenorhabditis elegans. PLoS One 2010; 5:e10422. [PMID: 20454655 PMCID: PMC2862703 DOI: 10.1371/journal.pone.0010422] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Accepted: 04/02/2010] [Indexed: 11/19/2022] Open
Abstract
Prolonged alcohol consumption in humans followed by abstinence precipitates a withdrawal syndrome consisting of anxiety, agitation and in severe cases, seizures. Withdrawal is relieved by a low dose of alcohol, a negative reinforcement that contributes to alcohol dependency. This phenomenon of ‘withdrawal relief’ provides evidence of an ethanol-induced adaptation which resets the balance of signalling in neural circuits. We have used this as a criterion to distinguish between direct and indirect ethanol-induced adaptive behavioural responses in C. elegans with the goal of investigating the genetic basis of ethanol-induced neural plasticity. The paradigm employs a ‘food race assay’ which tests sensorimotor performance of animals acutely and chronically treated with ethanol. We describe a multifaceted C. elegans ‘withdrawal syndrome’. One feature, decrease reversal frequency is not relieved by a low dose of ethanol and most likely results from an indirect adaptation to ethanol caused by inhibition of feeding and a food-deprived behavioural state. However another aspect, an aberrant behaviour consisting of spontaneous deep body bends, did show withdrawal relief and therefore we suggest this is the expression of ethanol-induced plasticity. The potassium channel, slo-1, which is a candidate ethanol effector in C. elegans, is not required for the responses described here. However a mutant deficient in neuropeptides, egl-3, is resistant to withdrawal (although it still exhibits acute responses to ethanol). This dependence on neuropeptides does not involve the NPY-like receptor npr-1, previously implicated in C. elegans ethanol withdrawal. Therefore other neuropeptide pathways mediate this effect. These data resonate with mammalian studies which report involvement of a number of neuropeptides in chronic responses to alcohol including corticotrophin-releasing-factor (CRF), opioids, tachykinins as well as NPY. This suggests an evolutionarily conserved role for neuropeptides in ethanol-induced plasticity and opens the way for a genetic analysis of the effects of alcohol on a simple model system.
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Abstract
Acute exposure to ethanol is known to modulate signalling within the nervous system. Physiologically these effects are both presynaptic and postsynaptic in origin; however, considerably more research has focused primarily on postsynaptic targets. Recent research using the model organism Caenorhabditis elegans has determined a role for specific proteins (Munc18-1 and Rab3) and processes (synaptic vesicle recruitment and fusion) in transducing the presynaptic effects of ethanol. In the present paper, we review these results, identifying the proteins and protein interactions involved in ethanol sensitivity and discuss their links with mammalian studies of alcohol abuse.
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Bhandari P, Kendler KS, Bettinger JC, Davies AG, Grotewiel M. An assay for evoked locomotor behavior in Drosophila reveals a role for integrins in ethanol sensitivity and rapid ethanol tolerance. Alcohol Clin Exp Res 2009; 33:1794-805. [PMID: 19645731 DOI: 10.1111/j.1530-0277.2009.01018.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Ethanol induces similar behavioral responses in mammals and the fruit fly, Drosophila melanogaster. By coupling assays for ethanol-related behavior to the genetic tools available in flies, a number of genes have been identified that influence physiological responses to ethanol. To enhance the utility of the Drosophila model for investigating genes involved in ethanol-related behavior, we explored the value of an assay that measures the sedative effects of ethanol on negative geotaxis, an evoked locomotor response. METHODS We established eRING (ethanol Rapid Iterative Negative Geotaxis) as an assay for quantitating the sedative effects of ethanol on negative geotaxis (i.e., startle-induced climbing). We validated the assay by assessing acute sensitivity to ethanol and rapid ethanol tolerance in several different control strains and in flies with mutations known to disrupt these behaviors. We also used eRING in a candidate screen to identify mutants with altered ethanol-related behaviors. RESULTS Negative geotaxis measured in eRING assays was dose-dependently impaired by ethanol exposure. Flies developed tolerance to the intoxicating effects of ethanol when tested during a second exposure. Ethanol sensitivity and rapid ethanol tolerance varied across 4 control strains, but internal ethanol concentrations were indistinguishable in the 4 strains during a first and second challenge with ethanol. Ethanol sensitivity and rapid ethanol tolerance, respectively, were altered in flies with mutations in amnesiac and hangover, genes known to influence these traits. Additionally, mutations in the beta integrin gene myospheroid and the alpha integrin gene scab increased the initial sensitivity to ethanol and enhanced the development of rapid ethanol tolerance without altering internal ethanol concentrations. CONCLUSIONS The eRING assay is suitable for investigating genetic mechanisms that influence ethanol sensitivity and rapid ethanol tolerance. Ethanol sensitivity and rapid ethanol tolerance depend on the function of alpha and beta integrins in flies.
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Affiliation(s)
- Poonam Bhandari
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia 23113, USA
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Graham ME, Edwards MR, Holden-Dye L, Morgan A, Burgoyne RD, Barclay JW. UNC-18 modulates ethanol sensitivity in Caenorhabditis elegans. Mol Biol Cell 2008; 20:43-55. [PMID: 18923141 DOI: 10.1091/mbc.e08-07-0689] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Acute ethanol exposure affects the nervous system as a stimulant at low concentrations and as a depressant at higher concentrations, eventually resulting in motor dysfunction and uncoordination. A recent genetic study of two mouse strains with varying ethanol preference indicated a correlation with a polymorphism (D216N) in the synaptic protein Munc18-1. Munc18-1 functions in exocytosis via a number of discrete interactions with the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein syntaxin-1. We report that the mutation affects binding to syntaxin but not through either a closed conformation mode of interaction or through binding to the syntaxin N terminus. The D216N mutant instead has a specific impairment in binding the assembled SNARE complex. Furthermore, the mutation broadens the duration of single exocytotic events. Expression of the orthologous mutation (D214N) in the Caenorhabditis elegans UNC-18 null background generated transgenic rescues with phenotypically similar locomotion to worms rescued with the wild-type protein. Strikingly, D214N worms were strongly resistant to both stimulatory and sedative effects of acute ethanol. Analysis of an alternative Munc18-1 mutation (I133V) supported the link between reduced SNARE complex binding and ethanol resistance. We conclude that ethanol acts, at least partially, at the level of vesicle fusion and that its acute effects are ameliorated by point mutations in UNC-18.
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Affiliation(s)
- Margaret E Graham
- The Physiological Laboratory, School of Biomedical Sciences, University of Liverpool, United Kingdom
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