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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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Brockmeier EK, Basili D, Herbert J, Rendal C, Boakes L, Grauslys A, Taylor NS, Danby EB, Gutsell S, Kanda R, Cronin M, Barclay J, Antczak P, Viant MR, Hodges G, Falciani F. Data-driven learning of narcosis mode of action identifies a CNS transcriptional signature shared between whole organism Caenorhabditis elegans and a fish gill cell line. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 849:157666. [PMID: 35908689 DOI: 10.1016/j.scitotenv.2022.157666] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 06/27/2022] [Accepted: 07/23/2022] [Indexed: 06/15/2023]
Abstract
With the large numbers of man-made chemicals produced and released in the environment, there is a need to provide assessments on their potential effects on environmental safety and human health. Current regulatory frameworks rely on a mix of both hazard and risk-based approaches to make safety decisions, but the large number of chemicals in commerce combined with an increased need to conduct assessments in the absence of animal testing makes this increasingly challenging. This challenge is catalysing the use of more mechanistic knowledge in safety assessment from both in silico and in vitro approaches in the hope that this will increase confidence in being able to identify modes of action (MoA) for the chemicals in question. Here we approach this challenge by testing whether a functional genomics approach in C. elegans and in a fish cell line can identify molecular mechanisms underlying the effects of narcotics, and the effects of more specific acting toxicants. We show that narcosis affects the expression of neuronal genes associated with CNS function in C. elegans and in a fish cell line. Overall, we believe that our study provides an important step in developing mechanistically relevant biomarkers which can be used to screen for hazards, and which prevent the need for repeated animal or cross-species comparisons for each new chemical.
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Affiliation(s)
- Erica K Brockmeier
- Department of Biochemistry & System Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Danilo Basili
- Department of Biochemistry & System Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Safety and Environmental Assurance Centre (SEAC), Unilever, Colworth Park, Sharnbrook, UK
| | - John Herbert
- Department of Biochemistry & System Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Cecilie Rendal
- Safety and Environmental Assurance Centre (SEAC), Unilever, Colworth Park, Sharnbrook, UK
| | - Leigh Boakes
- Department of Biochemistry & System Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Christeyns Food Hygiene, Warrington, UK
| | - Arturas Grauslys
- Department of Biochemistry & System Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Computational Biology Facility (CBF), University of Liverpool, Liverpool, UK
| | - Nadine S Taylor
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Emma Butler Danby
- Safety and Environmental Assurance Centre (SEAC), Unilever, Colworth Park, Sharnbrook, UK
| | - Steve Gutsell
- Safety and Environmental Assurance Centre (SEAC), Unilever, Colworth Park, Sharnbrook, UK
| | - Rakesh Kanda
- Institute of Environment, Health and Societies, Brunel University, London, UK
| | - Mark Cronin
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, UK
| | - Jeff Barclay
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Philipp Antczak
- Department of Biochemistry & System Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Computational Biology Facility (CBF), University of Liverpool, Liverpool, UK
| | - Mark R Viant
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Geoff Hodges
- Safety and Environmental Assurance Centre (SEAC), Unilever, Colworth Park, Sharnbrook, UK
| | - Francesco Falciani
- Department of Biochemistry & System Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Computational Biology Facility (CBF), University of Liverpool, Liverpool, UK.
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Li Y, Jiang L, Wang L, Wang C, Liu C, Guo A, Liu M, Zhang L, Ma C, Zhang X, Gao S, Liu JY. p.His16Arg of STXBP1 (MUNC18-1) Associated With Syntaxin 3B Causes Autosomal Dominant Congenital Nystagmus. Front Cell Dev Biol 2020; 8:591781. [PMID: 33251218 PMCID: PMC7672047 DOI: 10.3389/fcell.2020.591781] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/15/2020] [Indexed: 02/04/2023] Open
Abstract
Congenital nystagmus (CN) is an ocular movement disorder manifested as involuntary conjugated binocular oscillation and usually occurs in early infancy. The pathological mechanism underlying CN is still poorly understood. We mapped a novel genetic locus 9q33.1-q34.2 in a larger Chinese family with autosomal dominant CN and identified a variant (c.47A>G/p.His16Arg) of STXBP1 by exome sequencing, which fully co-segregated with the nystagmus phenotype in this family and was absent in 571 healthy unrelated individuals. The STXBP1 encodes syntaxin binding protein 1 (also known as MUNC18-1), which plays a pivotal role in neurotransmitter release. In unc-18 (nematode homolog of MUNC18-1) null Caenorhabditis elegans, we found that the p.His16Arg exhibits a compromised ability to rescue the locomotion defect and aldicarb sensitivity, indicating a functional defect in neurotransmitter release. In addition, we also found an enhanced binding of the p.His16Arg mutant to syntaxin 3B, which is a homolog of syntaxin 1A and specifically located in retinal ribbon synapses. We hypothesize that the variant p.His16Arg of STXBP1 is likely to affect neurotransmitter release in the retina, which may be the underlying etiology of CN in this family. Our results provide a new perspective on understanding the molecular mechanism of CN.
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Affiliation(s)
- Yulei Li
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.,School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, China
| | - Lei Jiang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Lejin Wang
- Department of Ophthalmology, Peking University People's Hospital, Beijing, China
| | - Cheng Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Chunjie Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Anyuan Guo
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Mugen Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Luoying Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Cong Ma
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Xianqin Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Shangbang Gao
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Yu Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
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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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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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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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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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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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