1
|
Echeverría F, Gonzalez-Sanabria N, Alvarado-Sanchez R, Fernández M, Castillo K, Latorre R. Large conductance voltage-and calcium-activated K + (BK) channel in health and disease. Front Pharmacol 2024; 15:1373507. [PMID: 38584598 PMCID: PMC10995336 DOI: 10.3389/fphar.2024.1373507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 03/12/2024] [Indexed: 04/09/2024] Open
Abstract
Large Conductance Voltage- and Calcium-activated K+ (BK) channels are transmembrane pore-forming proteins that regulate cell excitability and are also expressed in non-excitable cells. They play a role in regulating vascular tone, neuronal excitability, neurotransmitter release, and muscle contraction. Dysfunction of the BK channel can lead to arterial hypertension, hearing disorders, epilepsy, and ataxia. Here, we provide an overview of BK channel functioning and the implications of its abnormal functioning in various diseases. Understanding the function of BK channels is crucial for comprehending the mechanisms involved in regulating vital physiological processes, both in normal and pathological conditions, controlled by BK. This understanding may lead to the development of therapeutic interventions to address BK channelopathies.
Collapse
Affiliation(s)
- Felipe Echeverría
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Naileth Gonzalez-Sanabria
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Rosangelina Alvarado-Sanchez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Miguel Fernández
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Karen Castillo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro de Investigación de Estudios Avanzados del Maule, Vicerrectoría de Investigación y Postgrado, Universidad Católica del Maule, Talca, Chile
| | - Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| |
Collapse
|
2
|
Okhuarobo A, Kreifeldt M, Gandhi PJ, Lopez C, Martinez B, Fleck K, Bajo M, Bhattacharyya P, Dopico AM, Roberto M, Roberts AJ, Homanics GE, Contet C. Ethanol's interaction with BK channel α subunit residue K361 does not mediate behavioral responses to alcohol in mice. Mol Psychiatry 2024; 29:529-542. [PMID: 38135755 PMCID: PMC11116116 DOI: 10.1038/s41380-023-02346-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023]
Abstract
Large conductance potassium (BK) channels are among the most sensitive molecular targets of ethanol and genetic variations in the channel-forming α subunit have been nominally associated with alcohol use disorders. However, whether the action of ethanol at BK α influences the motivation to drink alcohol remains to be determined. To address this question, we first tested the effect of systemically administered BK channel modulators on voluntary alcohol consumption in C57BL/6J males. Penitrem A (blocker) exerted dose-dependent effects on moderate alcohol intake, while paxilline (blocker) and BMS-204352 (opener) were ineffective. Because pharmacological manipulations are inherently limited by non-specific effects, we then sought to investigate the behavioral relevance of ethanol's direct interaction with BK α by introducing in the mouse genome a point mutation known to render BK channels insensitive to ethanol while preserving their physiological function. The BK α K361N substitution prevented ethanol from reducing spike threshold in medial habenula neurons. However, it did not alter acute responses to ethanol in vivo, including ataxia, sedation, hypothermia, analgesia, and conditioned place preference. Furthermore, the mutation did not have reproducible effects on alcohol consumption in limited, continuous, or intermittent access home cage two-bottle choice paradigms conducted in both males and females. Notably, in contrast to previous observations made in mice missing BK channel auxiliary β subunits, the BK α K361N substitution had no significant impact on ethanol intake escalation induced by chronic intermittent alcohol vapor inhalation. It also did not affect the metabolic and locomotor consequences of chronic alcohol exposure. Altogether, these data suggest that the direct interaction of ethanol with BK α does not mediate the alcohol-related phenotypes examined here in mice.
Collapse
Affiliation(s)
- Agbonlahor Okhuarobo
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | - Max Kreifeldt
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | - Pauravi J Gandhi
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | - Catherine Lopez
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | - Briana Martinez
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | - Kiera Fleck
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | - Michal Bajo
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | | | - Alex M Dopico
- University of Tennessee Health Science Center, Department of Pharmacology, Addiction Science, and Toxicology, Memphis, TN, USA
| | - Marisa Roberto
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | - Amanda J Roberts
- The Scripps Research Institute, Animals Models Core Facility, La Jolla, CA, USA
| | - Gregg E Homanics
- University of Pittsburgh, Department of Anesthesiology and Perioperative Medicine, Pittsburgh, PA, USA
| | - Candice Contet
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA.
| |
Collapse
|
3
|
Taylor A, Adank DN, Young PA, Quan Y, Nabit BP, Winder DG. Forced Abstinence from Volitional Ethanol Intake Drives a Vulnerable Period of Hyperexcitability in BNST-Projecting Insular Cortex Neurons. J Neurosci 2024; 44:e1121232023. [PMID: 38050120 PMCID: PMC10860622 DOI: 10.1523/jneurosci.1121-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 10/26/2023] [Accepted: 11/13/2023] [Indexed: 12/06/2023] Open
Abstract
The insular cortex (IC) integrates sensory and interoceptive cues to inform downstream circuitry executing adaptive behavioral responses. The IC communicates with areas involved canonically in stress and motivation. IC projections govern stress and ethanol recruitment of bed nucleus of the stria terminalis (BNST) activity necessary for the emergence of negative affective behaviors during alcohol abstinence. Here, we assess the impact of the chronic drinking forced abstinence (CDFA) volitional home cage ethanol intake paradigm on synaptic and excitable properties of IC neurons that project to the BNST (IC→BNST). Using whole-cell patch-clamp electrophysiology, we investigated IC→BNST circuitry 24 h or 2 weeks following forced abstinence (FA) in female C57BL6/J mice. We find that IC→BNST cells are transiently more excitable following acute ethanol withdrawal. In contrast, in vivo ethanol exposure via intraperitoneal injection, ex vivo via ethanol wash, and acute FA from a natural reward (sucrose) all failed to alter excitability. In situ hybridization studies revealed that at 24 h post FA BK channel mRNA expression is reduced in IC. Further, pharmacological inhibition of BK channels mimicked the 24 h FA phenotype, while BK activation was able to decrease AP firing in control and 24 h FA subjects. All together these data suggest a novel mechanism of homeostatic plasticity that occurs in the IC→BNST circuitry following chronic drinking.
Collapse
Affiliation(s)
- Anne Taylor
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee 37235
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37235
| | - Danielle N Adank
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee 37235
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37235
| | - Phoebe A Young
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37235
| | - Yizhen Quan
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37235
| | - Brett P Nabit
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37235
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37235
| | - Danny G Winder
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee 37235
- Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, Tennessee 37235
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37235
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37235
| |
Collapse
|
4
|
Martins AC, Virgolini MB, Ávila DS, Scharf P, Li J, Tinkov AA, Skalny AV, Bowman AB, Rocha JBT, Aschner M. Mitochondria in the Spotlight: C. elegans as a Model Organism to Evaluate Xenobiotic-Induced Dysfunction. Cells 2023; 12:2124. [PMID: 37681856 PMCID: PMC10486742 DOI: 10.3390/cells12172124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/19/2023] [Accepted: 08/20/2023] [Indexed: 09/09/2023] Open
Abstract
Mitochondria play a crucial role in cellular respiration, ATP production, and the regulation of various cellular processes. Mitochondrial dysfunctions have been directly linked to pathophysiological conditions, making them a significant target of interest in toxicological research. In recent years, there has been a growing need to understand the intricate effects of xenobiotics on human health, necessitating the use of effective scientific research tools. Caenorhabditis elegans (C. elegans), a nonpathogenic nematode, has emerged as a powerful tool for investigating toxic mechanisms and mitochondrial dysfunction. With remarkable genetic homology to mammals, C. elegans has been used in studies to elucidate the impact of contaminants and drugs on mitochondrial function. This review focuses on the effects of several toxic metals and metalloids, drugs of abuse and pesticides on mitochondria, highlighting the utility of C. elegans as a model organism to investigate mitochondrial dysfunction induced by xenobiotics. Mitochondrial structure, function, and dynamics are discussed, emphasizing their essential role in cellular viability and the regulation of processes such as autophagy, apoptosis, and calcium homeostasis. Additionally, specific toxins and toxicants, such as arsenic, cadmium, and manganese are examined in the context of their impact on mitochondrial function and the utility of C. elegans in elucidating the underlying mechanisms. Furthermore, we demonstrate the utilization of C. elegans as an experimental model providing a promising platform for investigating the intricate relationships between xenobiotics and mitochondrial dysfunction. This knowledge could contribute to the development of strategies to mitigate the adverse effects of contaminants and drugs of abuse, ultimately enhancing our understanding of these complex processes and promoting human health.
Collapse
Affiliation(s)
- Airton C. Martins
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA;
| | - Miriam B. Virgolini
- Departamento de Farmacología Otto Orsingher, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina
- Instituto de Farmacología Experimental de Córdoba-Consejo Nacional de Investigaciones Técnicas (IFEC-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina
| | - Daiana Silva Ávila
- Laboratory of Biochemistry and Toxicology in Caenorhabditis Elegans, Universidade Federal do Pampa, Campus Uruguaiana, BR-472 Km 592, Uruguaiana 97500-970, RS, Brazil
| | - Pablo Scharf
- Department of Clinical and Toxicological Analyses, Faculty of Pharmaceutical Sciences, University of São Paulo, São Paulo 05508-000, SP, Brazil
| | - Jung Li
- College of Osteopathic Medicine, Des Moines University, Des Moines, IA 50312, USA
| | - Alexey A. Tinkov
- Laboratory of Ecobiomonitoring and Quality Control, Yaroslavl State University, Yaroslavl 150003, Russia
- Laboratory of Molecular Dietetics, IM Sechenov First Moscow State Medical University (Sechenov University), Moscow 119435, Russia
| | - Anatoly V. Skalny
- Laboratory of Ecobiomonitoring and Quality Control, Yaroslavl State University, Yaroslavl 150003, Russia
- Laboratory of Molecular Dietetics, IM Sechenov First Moscow State Medical University (Sechenov University), Moscow 119435, Russia
- Peoples Friendship University of Russia (RUDN University), Moscow 117198, Russia
| | - Aaron B. Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN 47907-2051, USA
| | - João B. T. Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria 97105-900, RS, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA;
| |
Collapse
|
5
|
van Wijk MH, Davies AG, Sterken MG, Mathies LD, Quamme EC, Blackwell GG, Riksen JAG, Kammenga JE, Bettinger JC. Natural allelic variation modifies acute ethanol response phenotypes in wild strains of C. elegans. ALCOHOL, CLINICAL & EXPERIMENTAL RESEARCH 2023; 47:1505-1517. [PMID: 37356915 DOI: 10.1111/acer.15139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/12/2023] [Accepted: 06/20/2023] [Indexed: 06/27/2023]
Abstract
BACKGROUND Genetic variation contributes to the likelihood that an individual will develop an alcohol use disorder (AUD). Traditional laboratory studies in animal models have elucidated the molecular pharmacology of ethanol, but laboratory-derived genetic manipulations rarely model the naturally occurring genetic variation observed in wild populations. Rather, these manipulations are biased toward identifying genes of central importance in the phenotypes. Because changes in such genes can confer selective disadvantages, they are not ideal candidates for carrying AUD risk alleles in humans. We sought to exploit Caenorhabditis elegans to identify allelic variation existing in the wild that modulates ethanol response behaviors. METHODS We tested the acute ethanol responses of four strains recently isolated from the wild (JU1511, JU1926, JU1931, and JU1941) and 41 multiparental recombinant inbred lines (mpRILs) derived from them. We assessed locomotion at 10, 30, and 50 min on low and high ethanol concentrations. We performed principal component analyses (PCA) on the different phenotypes, tested for transgressive behavior, calculated heritability, and determined the correlations between behavioral responses. RESULTS We observed a range of responses to ethanol across the strains. We detected a low-concentration locomotor activation effect in some of the mpRILs not seen in the laboratory wild-type strain. PCA showed different ethanol response behaviors to be independent. We observed transgressive behavior for many of the measured phenotypes and found that multiple behaviors were uncorrelated. The average broad-sense heritability for all phenotypes was 23.2%. CONCLUSIONS Genetic variation significantly affects multiple acute ethanol response behaviors, many of which are independent of one another. This suggests that the genetic variation captured by these strains likely affects multiple biological mechanisms through which ethanol acts. Further study of these strains may allow these distinct mechanisms to be identified.
Collapse
Affiliation(s)
- Marijke H van Wijk
- Laboratory of Nematology, Wageningen University & Research, Wageningen, The Netherlands
| | - Andrew G Davies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Mark G Sterken
- Laboratory of Nematology, Wageningen University & Research, Wageningen, The Netherlands
| | - Laura D Mathies
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Elizabeth C Quamme
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - GinaMari G Blackwell
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Joost A G Riksen
- Laboratory of Nematology, Wageningen University & Research, Wageningen, The Netherlands
| | - Jan E Kammenga
- Laboratory of Nematology, Wageningen University & Research, Wageningen, The Netherlands
| | - Jill C Bettinger
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| |
Collapse
|
6
|
Didier N, Vena A, Feather AR, Grant JE, King AC. Holding your liquor: Comparison of alcohol-induced psychomotor impairment in drinkers with and without alcohol use disorder. Alcohol Clin Exp Res 2023. [PMID: 37330919 DOI: 10.1111/acer.15080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 04/03/2023] [Indexed: 06/20/2023]
Abstract
BACKGROUND Behavioral tolerance to alcohol underscores the widely accepted notion that individuals who regularly drink alcohol become less sensitive to its impairing effects. However, previous research assessing alcohol-induced impairment in humans has primarily focused on social drinkers. This has limited our understanding of the nature and extent of behavioral tolerance among heavier drinkers, such as those with alcohol use disorder (AUD). METHODS Data from three cohorts of the Chicago Social Drinking Project were evaluated to examine the acute effects of alcohol on psychomotor performance across the breath alcohol curve in light drinkers (LDs; n = 86), heavy drinkers (HDs; n = 208), and individuals with AUD (AUDs; n = 103). Before and at several intervals after ingesting either alcohol (0.8 g/kg, peak BrAC = 0.09 g/dL) or placebo in two random-order laboratory sessions, participants completed a test of fine motor coordination (Grooved Pegboard), a test of perceptual-motor processing (Digit Symbol Substitution Task), and a self-reported survey of perceived impairment. Sixty individuals with AUD completed a third session with a very high dose of alcohol (1.2 g/kg, peak BrAC = 0.13 g/dL). RESULTS The AUD and HD groups, relative to the LD group, perceived less impairment and demonstrated greater behavioral tolerance to an intoxicating dose of alcohol, exhibited by reduced peak impairment and a quicker return to baseline performance on psychomotor measures. Among individuals with AUD who consumed the very high dose, impairment was more than double that following the usual high dose, and it exceeded the impairment among LDs following the usual high dose. CONCLUSIONS In this sample of young adult drinkers, relative to the LD group, those with heavier drinking patterns (AUD and HD groups) showed greater behavioral tolerance to 0.8 g/kg alcohol, a dose typically associated with a binge drinking episode. However, when challenged with a very high alcohol dose commensurate with high-intensity drinking, individuals with AUD showed substantial psychomotor impairment.
Collapse
Affiliation(s)
- Nathan Didier
- Department of Psychiatry and Behavioral Neuroscience, The University of Chicago, Chicago, Illinois, USA
| | - Ashley Vena
- Department of Psychiatry and Behavioral Neuroscience, The University of Chicago, Chicago, Illinois, USA
| | - Abigayle R Feather
- Department of Psychiatry and Behavioral Neuroscience, The University of Chicago, Chicago, Illinois, USA
| | - Jon E Grant
- Department of Psychiatry and Behavioral Neuroscience, The University of Chicago, Chicago, Illinois, USA
| | - Andrea C King
- Department of Psychiatry and Behavioral Neuroscience, The University of Chicago, Chicago, Illinois, USA
| |
Collapse
|
7
|
Williams J, Xu S, Ferreira MAR. BGWAS: Bayesian variable selection in linear mixed models with nonlocal priors for genome-wide association studies. BMC Bioinformatics 2023; 24:194. [PMID: 37170185 PMCID: PMC10176706 DOI: 10.1186/s12859-023-05316-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 04/30/2023] [Indexed: 05/13/2023] Open
Abstract
BACKGROUND Genome-wide association studies (GWAS) seek to identify single nucleotide polymorphisms (SNPs) that cause observed phenotypes. However, with highly correlated SNPs, correlated observations, and the number of SNPs being two orders of magnitude larger than the number of observations, GWAS procedures often suffer from high false positive rates. RESULTS We propose BGWAS, a novel Bayesian variable selection method based on nonlocal priors for linear mixed models specifically tailored for genome-wide association studies. Our proposed method BGWAS uses a novel nonlocal prior for linear mixed models (LMMs). BGWAS has two steps: screening and model selection. The screening step scans through all the SNPs fitting one LMM for each SNP and then uses Bayesian false discovery control to select a set of candidate SNPs. After that, a model selection step searches through the space of LMMs that may have any number of SNPs from the candidate set. A simulation study shows that, when compared to popular GWAS procedures, BGWAS greatly reduces false positives while maintaining the same ability to detect true positive SNPs. We show the utility and flexibility of BGWAS with two case studies: a case study on salt stress in plants, and a case study on alcohol use disorder. CONCLUSIONS BGWAS maintains and in some cases increases the recall of true SNPs while drastically lowering the number of false positives compared to popular SMA procedures.
Collapse
Affiliation(s)
- Jacob Williams
- Department of Statistics, Virginia Tech, Blacksburg, 24061, USA.
| | - Shuangshuang Xu
- Department of Statistics, Virginia Tech, Blacksburg, 24061, USA
| | | |
Collapse
|
8
|
Mysiewicz S, North KC, Moreira L, Odum SJ, Bukiya AN, Dopico AM. Interspecies and regional variability of alcohol action on large cerebral arteries: regulation by KCNMB1 proteins. Am J Physiol Regul Integr Comp Physiol 2023; 324:R480-R496. [PMID: 36717168 PMCID: PMC10027090 DOI: 10.1152/ajpregu.00103.2022] [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: 05/12/2022] [Revised: 01/23/2023] [Accepted: 01/23/2023] [Indexed: 02/01/2023]
Abstract
Alcohol intake leading to blood ethanol concentrations (BEC) ≥ legal intoxication modifies brain blood flow with increases in some regions and decreases in others. Brain regions receive blood from the Willis' circle branches: anterior, middle (MCA) and posterior cerebral (PCA), and basilar (BA) arteries. Rats and mice have been used to identify the targets mediating ethanol-induced effects on cerebral arteries, with conclusions being freely interchanged, albeit data were obtained in different species/arterial branches. We tested whether ethanol action on cerebral arteries differed between male rat and mouse and/or across different brain regions and identified the targets of alcohol action. In both species and all Willis' circle branches, ethanol evoked reversible and concentration-dependent constriction (EC50s ≈ 37-86 mM; below lethal BEC in alcohol-naïve humans). Although showing similar constriction to depolarization, both species displayed differential responses to ethanol: in mice, MCA constriction was highly sensitive to the presence/absence of the endothelium, whereas in rat PCA was significantly more sensitive to ethanol than its mouse counterpart. In the rat, but not the mouse, BA was more ethanol sensitive than other branches. Both interspecies and regional variability were ameliorated by endothelium. Selective large conductance (BK) channel block in de-endothelialized vessels demonstrated that these channels were the effectors of alcohol-induced cerebral artery constriction across regions and species. Variabilities in alcohol actions did not fully matched KCNMB1 expression across vessels. However, immunofluorescence data from KCNMB1-/- mouse arteries electroporated with KCNMB1-coding cDNA demonstrate that KCNMB1 proteins, which regulate smooth muscle (SM) BK channel function and vasodilation, regulate interspecies and regional variability of brain artery responses to alcohol.
Collapse
Affiliation(s)
- Steven Mysiewicz
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Kelsey C North
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Luiz Moreira
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Schyler J Odum
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Anna N Bukiya
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee, United States
| | - Alex M Dopico
- Department of Pharmacology, Addiction Science, and Toxicology, College of Medicine, The University of Tennessee Health Science Center, Memphis, Tennessee, United States
| |
Collapse
|
9
|
Williams J, Ferreira MAR, Ji T. BICOSS: Bayesian iterative conditional stochastic search for GWAS. BMC Bioinformatics 2022; 23:475. [DOI: 10.1186/s12859-022-05030-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 10/31/2022] [Indexed: 11/15/2022] Open
Abstract
Abstract
Background
Single marker analysis (SMA) with linear mixed models for genome wide association studies has uncovered the contribution of genetic variants to many observed phenotypes. However, SMA has weak false discovery control. In addition, when a few variants have large effect sizes, SMA has low statistical power to detect small and medium effect sizes, leading to low recall of true causal single nucleotide polymorphisms (SNPs).
Results
We present the Bayesian Iterative Conditional Stochastic Search (BICOSS) method that controls false discovery rate and increases recall of variants with small and medium effect sizes. BICOSS iterates between a screening step and a Bayesian model selection step. A simulation study shows that, when compared to SMA, BICOSS dramatically reduces false discovery rate and allows for smaller effect sizes to be discovered. Finally, two real world applications show the utility and flexibility of BICOSS.
Conclusions
When compared to widely used SMA, BICOSS provides higher recall of true SNPs while dramatically reducing false discovery rate.
Collapse
|
10
|
Guzman DM, Chakka K, Shi T, Marron A, Fiorito AE, Rahman NS, Ro S, Sucich DG, Pierce JT. Transgenerational effects of alcohol on behavioral sensitivity to alcohol in Caenorhabditis elegans. PLoS One 2022; 17:e0271849. [PMID: 36256641 PMCID: PMC9578632 DOI: 10.1371/journal.pone.0271849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 09/29/2022] [Indexed: 11/06/2022] Open
Abstract
Alcohol abuse and dependence have a substantial heritable component. Although the genome has been considered the sole vehicle of heritable phenotypes, recent studies suggest that drug or alcohol exposure may induce alterations in gene expression that are transmitted across generations. Still, the transgenerational impact of alcohol use (and abuse) remains largely unexplored in part because multigenerational studies using rodent models present challenges for time, sample size, and genetic heterogeneity. Here, we took advantage of the extremely short generation time, large broods, and clonal form of reproduction of the nematode Caenorhabditis elegans. We developed a model of pre-fertilization parental alcohol exposure to test alterations in behavioral responses to acute alcohol treatment (referred to in short as intoxication) in subsequent F1, F2 and F3 generations. We found that chronic and intermittent alcohol-treatment paradigms resulted in opposite changes to intoxication sensitivity of F3 progeny that were only apparent when controlling for yoked trials. Chronic alcohol-treatment paradigm in the parental generation resulted in alcohol-naïve F3 progeny displaying moderate resistance to intoxication. Intermittent treatment resulted in alcohol-naïve F3 progeny displaying moderate hypersensitivity to intoxication. Further study of these phenomena using this new C. elegans model may yield mechanistic insights into how transgenerational effects may occur in other animals.
Collapse
Affiliation(s)
- Dawn M. Guzman
- Department of Neuroscience, Waggoner Center for Alcohol and Addiction Research, Center for Learning and Memory, University of Texas at Austin, Austin, Texas, United States of America
| | - Keerthana Chakka
- Department of Neuroscience, Waggoner Center for Alcohol and Addiction Research, Center for Learning and Memory, University of Texas at Austin, Austin, Texas, United States of America
| | - Ted Shi
- Department of Neuroscience, Waggoner Center for Alcohol and Addiction Research, Center for Learning and Memory, University of Texas at Austin, Austin, Texas, United States of America
| | - Alyssa Marron
- Department of Neuroscience, Waggoner Center for Alcohol and Addiction Research, Center for Learning and Memory, University of Texas at Austin, Austin, Texas, United States of America
| | - Ansley E. Fiorito
- Department of Neuroscience, Waggoner Center for Alcohol and Addiction Research, Center for Learning and Memory, University of Texas at Austin, Austin, Texas, United States of America
| | - Nima S. Rahman
- Department of Neuroscience, Waggoner Center for Alcohol and Addiction Research, Center for Learning and Memory, University of Texas at Austin, Austin, Texas, United States of America
| | - Stephanie Ro
- Department of Neuroscience, Waggoner Center for Alcohol and Addiction Research, Center for Learning and Memory, University of Texas at Austin, Austin, Texas, United States of America
| | - Dylan G. Sucich
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Jonathan T. Pierce
- Department of Neuroscience, Waggoner Center for Alcohol and Addiction Research, Center for Learning and Memory, University of Texas at Austin, Austin, Texas, United States of America
| |
Collapse
|
11
|
Albrecht PA, Fernandez-Hubeid L.E, Deza-Ponzio R, Virgolini MB. The intertwining between lead and ethanol in the model organism Caenorhabditis elegans. FRONTIERS IN TOXICOLOGY 2022; 4:991787. [PMID: 36204698 PMCID: PMC9531147 DOI: 10.3389/ftox.2022.991787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022] Open
Abstract
Caenorhabditis elegans (C. elegans) is a model organism widely used to evaluate the mechanistic aspects of toxicants with the potential to predict responses comparable to those of mammals. We report here the consequences of developmental lead (Pb) exposure on behavioral responses to ethanol (EtOH) in C. elegans. In addition, we present data on morphological alterations in the dopamine (DA) synapse and DA-dependent behaviors aimed to dissect the neurobiological mechanisms that underlie the relationship between these neurotoxicants. Finally, the escalation to superior animals that parallels the observed effects in both experimental models with references to EtOH metabolism and oxidative stress is also discussed. Overall, the literature revised here underpins the usefulness of C. elegans to evidence behavioral responses to a combination of neurotoxicants in mechanistic-orientated studies.
Collapse
Affiliation(s)
- P. A. Albrecht
- Departamento de Farmacología Otto Orsingher, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Instituto de Farmacología Experimental de Córdoba-Consejo Nacional de Investigaciones Científicas y Técnicas (IFEC-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - L .E. Fernandez-Hubeid
- Departamento de Farmacología Otto Orsingher, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Instituto de Farmacología Experimental de Córdoba-Consejo Nacional de Investigaciones Científicas y Técnicas (IFEC-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - R. Deza-Ponzio
- Departamento de Farmacología Otto Orsingher, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Instituto de Farmacología Experimental de Córdoba-Consejo Nacional de Investigaciones Científicas y Técnicas (IFEC-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - M. B. Virgolini
- Departamento de Farmacología Otto Orsingher, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- Instituto de Farmacología Experimental de Córdoba-Consejo Nacional de Investigaciones Científicas y Técnicas (IFEC-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- *Correspondence: M. B. Virgolini,
| |
Collapse
|
12
|
Convergence of case-specific epigenetic alterations identify a confluence of genetic vulnerabilities tied to opioid overdose. Mol Psychiatry 2022; 27:2158-2170. [PMID: 35301427 PMCID: PMC9133127 DOI: 10.1038/s41380-022-01477-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 01/19/2022] [Accepted: 02/08/2022] [Indexed: 11/08/2022]
Abstract
Opioid use disorder is a highly heterogeneous disease driven by a variety of genetic and environmental risk factors which have yet to be fully elucidated. Opioid overdose, the most severe outcome of opioid use disorder, remains the leading cause of accidental death in the United States. We interrogated the effects of opioid overdose on the brain using ChIP-seq to quantify patterns of H3K27 acetylation in dorsolateral prefrontal cortical neurons isolated from 51 opioid-overdose cases and 51 accidental death controls. Among opioid cases, we observed global hypoacetylation and identified 388 putative enhancers consistently depleted for H3K27ac. Machine learning on H3K27ac patterns predicted case-control status with high accuracy. We focused on case-specific regulatory alterations, revealing 81,399 hypoacetylation events, uncovering vast inter-patient heterogeneity. We developed a strategy to decode this heterogeneity based on convergence analysis, which leveraged promoter-capture Hi-C to identify five genes over-burdened by alterations in their regulatory network or "plexus": ASTN2, KCNMA1, DUSP4, GABBR2, ENOX1. These convergent loci are enriched for opioid use disorder risk genes and heritability for generalized anxiety, number of sexual partners, and years of education. Overall, our multi-pronged approach uncovers neurobiological aspects of opioid use disorder and captures genetic and environmental factors perpetuating the opioid epidemic.
Collapse
|
13
|
Sheardown E, Mech AM, Petrazzini MEM, Leggieri A, Gidziela A, Hosseinian S, Sealy IM, Torres-Perez JV, Busch-Nentwich EM, Malanchini M, Brennan CH. Translational relevance of forward genetic screens in animal models for the study of psychiatric disease. Neurosci Biobehav Rev 2022; 135:104559. [PMID: 35124155 PMCID: PMC9016269 DOI: 10.1016/j.neubiorev.2022.104559] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 12/10/2021] [Accepted: 02/01/2022] [Indexed: 12/16/2022]
Abstract
Psychiatric disorders represent a significant burden in our societies. Despite the convincing evidence pointing at gene and gene-environment interaction contributions, the role of genetics in the etiology of psychiatric disease is still poorly understood. Forward genetic screens in animal models have helped elucidate causal links. Here we discuss the application of mutagenesis-based forward genetic approaches in common animal model species: two invertebrates, nematodes (Caenorhabditis elegans) and fruit flies (Drosophila sp.); and two vertebrates, zebrafish (Danio rerio) and mice (Mus musculus), in relation to psychiatric disease. We also discuss the use of large scale genomic studies in human populations. Despite the advances using data from human populations, animal models coupled with next-generation sequencing strategies are still needed. Although with its own limitations, zebrafish possess characteristics that make them especially well-suited to forward genetic studies exploring the etiology of psychiatric disorders.
Collapse
Affiliation(s)
- Eva Sheardown
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK
| | - Aleksandra M Mech
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK
| | | | - Adele Leggieri
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK
| | - Agnieszka Gidziela
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK
| | - Saeedeh Hosseinian
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK
| | - Ian M Sealy
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, UK
| | - Jose V Torres-Perez
- UK Dementia Research Institute at Imperial College London and Department of Brain Sciences, Imperial College London, 86 Wood Lane, London W12 0BZ, UK
| | - Elisabeth M Busch-Nentwich
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK
| | - Margherita Malanchini
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK
| | - Caroline H Brennan
- School of Biological and Behavioural Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, England, UK.
| |
Collapse
|
14
|
Salim C, Kan AK, Batsaikhan E, Patterson EC, Jee C. Neuropeptidergic regulation of compulsive ethanol seeking in C. elegans. Sci Rep 2022; 12:1804. [PMID: 35110557 PMCID: PMC8810865 DOI: 10.1038/s41598-022-05256-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 01/07/2022] [Indexed: 11/09/2022] Open
Abstract
Despite the catastrophic consequences of alcohol abuse, alcohol use disorders (AUD) and comorbidities continue to strain the healthcare system, largely due to the effects of alcohol-seeking behavior. An improved understanding of the molecular basis of alcohol seeking will lead to enriched treatments for these disorders. Compulsive alcohol seeking is characterized by an imbalance between the superior drive to consume alcohol and the disruption or erosion in control of alcohol use. To model the development of compulsive engagement in alcohol seeking, we simultaneously exploited two distinct and conflicting Caenorhabditis elegans behavioral programs, ethanol preference and avoidance of aversive stimulus. We demonstrate that the C. elegans model recapitulated the pivotal features of compulsive alcohol seeking in mammals, specifically repeated attempts, endurance, and finally aversion-resistant alcohol seeking. We found that neuropeptide signaling via SEB-3, a CRF receptor-like GPCR, facilitates the development of ethanol preference and compels animals to seek ethanol compulsively. Furthermore, our functional genomic approach and behavioral elucidation suggest that the SEB-3 regulates another neuropeptidergic signaling, the neurokinin receptor orthologue TKR-1, to facilitate compulsive ethanol-seeking behavior.
Collapse
Affiliation(s)
- Chinnu Salim
- Department of Pharmacology, Addiction Science and Toxicology, College of Medicine, University of Tennessee Health Science Center (UTHSC), 71 S. Manassas St., Suite 217, Memphis, TN, 38103, USA
| | - Ann Ke Kan
- Department of Pharmacology, Addiction Science and Toxicology, College of Medicine, University of Tennessee Health Science Center (UTHSC), 71 S. Manassas St., Suite 217, Memphis, TN, 38103, USA
| | - Enkhzul Batsaikhan
- Department of Pharmacology, Addiction Science and Toxicology, College of Medicine, University of Tennessee Health Science Center (UTHSC), 71 S. Manassas St., Suite 217, Memphis, TN, 38103, USA
| | - E Clare Patterson
- Department of Pharmacology, Addiction Science and Toxicology, College of Medicine, University of Tennessee Health Science Center (UTHSC), 71 S. Manassas St., Suite 217, Memphis, TN, 38103, USA
| | - Changhoon Jee
- Department of Pharmacology, Addiction Science and Toxicology, College of Medicine, University of Tennessee Health Science Center (UTHSC), 71 S. Manassas St., Suite 217, Memphis, TN, 38103, USA.
| |
Collapse
|
15
|
Pandey P, Singh A, Kaur H, Ghosh-Roy A, Babu K. Increased dopaminergic neurotransmission results in ethanol dependent sedative behaviors in Caenorhabditis elegans. PLoS Genet 2021; 17:e1009346. [PMID: 33524034 PMCID: PMC7877767 DOI: 10.1371/journal.pgen.1009346] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 02/11/2021] [Accepted: 01/06/2021] [Indexed: 12/19/2022] Open
Abstract
Ethanol is a widely used drug, excessive consumption of which could lead to medical conditions with diverse symptoms. Ethanol abuse causes dysfunction of memory, attention, speech and locomotion across species. Dopamine signaling plays an essential role in ethanol dependent behaviors in animals ranging from C. elegans to humans. We devised an ethanol dependent assay in which mutants in the dopamine autoreceptor, dop-2, displayed a unique sedative locomotory behavior causing the animals to move in circles while dragging the posterior half of their body. Here, we identify the posterior dopaminergic sensory neuron as being essential to modulate this behavior. We further demonstrate that in dop-2 mutants, ethanol exposure increases dopamine secretion and functions in a DVA interneuron dependent manner. DVA releases the neuropeptide NLP-12 that is known to function through cholinergic motor neurons and affect movement. Thus, DOP-2 modulates dopamine levels at the synapse and regulates alcohol induced movement through NLP-12.
Collapse
Affiliation(s)
- Pratima Pandey
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, India
| | - Anuradha Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, India
| | - Harjot Kaur
- National Brain Research Centre, Gurgaon, India
| | | | - Kavita Babu
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Mohali, India
- Centre for Neuroscience, Indian Institute of Science (IISc), Bangalore, India
| |
Collapse
|
16
|
Shaidullov I, Ermakova E, Gaifullina A, Mosshammer A, Yakovlev A, Weiger TM, Hermann A, Sitdikova G. Alcohol metabolite acetic acid activates BK channels in a pH-dependent manner and decreases calcium oscillations and exocytosis of secretory granules in rat pituitary GH3 cells. Pflugers Arch 2021; 473:67-77. [PMID: 33113008 DOI: 10.1007/s00424-020-02484-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 12/11/2022]
Abstract
Acetaldehyde and acetic acid/acetate, the active metabolites of alcohol (ethanol, EtOH), generate actions of their own ranging from behavioral, physiological, to pathological/cancerogenic effects. EtOH and acetaldehyde have been studied to some depth, whereas the effects of acetic acid have been less well explored. In this study, we investigated the effect of acetic acid on big conductance calcium-activated potassium (BK) channels present in GH3 rat pituitary tumor cells in more detail. In whole cell voltage clamp recordings, extracellular application of acetic acid increased total outward currents in a dose-dependent manner. This effect was prevented after the application of the specific BK channel blocker paxilline. Acetic acid action was pH-dependent-in whole cell current and single BK channel recordings, open probability (Po) was significantly increased by extracellular pH reduction and decreased by neutral or base pH. Acetic acid hyperpolarized the membrane potential, whereas acidic physiological solution had a depolarizing effect. Moreover, acetic acid reduced calcium (Ca2+) oscillations and exocytosis of growth hormone contained secretory granules from GH3 cells. These effects were partially prevented by BK inhibitors-tetraethylammonium or paxillin. In conclusion, our experiments indicate that acetic acid activates BK channels in GH3 cells which eventually contribute to acetic acid-induced membrane hyperpolarization, cessation of Ca2+ oscillations, and decrease of growth hormone release.
Collapse
Affiliation(s)
- Ilnar Shaidullov
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str. 18, Kazan, 420008, Russia
| | - Elizaveta Ermakova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str. 18, Kazan, 420008, Russia
| | | | - Anna Mosshammer
- Department of Neurophysiology and Neuropharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Aleksey Yakovlev
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str. 18, Kazan, 420008, Russia
| | - Thomas M Weiger
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | - Anton Hermann
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | - Guzel Sitdikova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kremlevskaya str. 18, Kazan, 420008, Russia.
| |
Collapse
|
17
|
Parker CC, Lusk R, Saba LM. Alcohol Sensitivity as an Endophenotype of Alcohol Use Disorder: Exploring Its Translational Utility between Rodents and Humans. Brain Sci 2020; 10:E725. [PMID: 33066036 PMCID: PMC7600833 DOI: 10.3390/brainsci10100725] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/06/2020] [Accepted: 10/09/2020] [Indexed: 12/21/2022] Open
Abstract
Alcohol use disorder (AUD) is a complex, chronic, relapsing disorder with multiple interacting genetic and environmental influences. Numerous studies have verified the influence of genetics on AUD, yet the underlying biological pathways remain unknown. One strategy to interrogate complex diseases is the use of endophenotypes, which deconstruct current diagnostic categories into component traits that may be more amenable to genetic research. In this review, we explore how an endophenotype such as sensitivity to alcohol can be used in conjunction with rodent models to provide mechanistic insights into AUD. We evaluate three alcohol sensitivity endophenotypes (stimulation, intoxication, and aversion) for their translatability across human and rodent research by examining the underlying neurobiology and its relationship to consumption and AUD. We show examples in which results gleaned from rodents are successfully integrated with information from human studies to gain insight in the genetic underpinnings of AUD and AUD-related endophenotypes. Finally, we identify areas for future translational research that could greatly expand our knowledge of the biological and molecular aspects of the transition to AUD with the broad hope of finding better ways to treat this devastating disorder.
Collapse
Affiliation(s)
- Clarissa C. Parker
- Department of Psychology and Program in Neuroscience, Middlebury College, Middlebury, VT 05753, USA
| | - Ryan Lusk
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA;
| | - Laura M. Saba
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA;
| |
Collapse
|
18
|
Schmitt RE, Messick MR, Shell BC, Dunbar EK, Fang H, Shelton KL, Venton BJ, Pletcher SD, Grotewiel M. Dietary yeast influences ethanol sedation in Drosophila via serotonergic neuron function. Addict Biol 2020; 25:e12779. [PMID: 31169340 DOI: 10.1111/adb.12779] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Revised: 03/23/2019] [Accepted: 05/02/2019] [Indexed: 01/10/2023]
Abstract
Abuse of alcohol is a major clinical problem with far-reaching health consequences. Understanding the environmental and genetic factors that contribute to alcohol-related behaviors is a potential gateway for developing novel therapeutic approaches for patients that abuse the drug. To this end, we have used Drosophila melanogaster as a model to investigate the effect of diet, an environmental factor, on ethanol sedation. Providing flies with diets high in yeast, a routinely used component of fly media, increased their resistance to ethanol sedation. The yeast-induced resistance to ethanol sedation occurred in several different genetic backgrounds, was observed in males and females, was elicited by yeast from different sources, was readily reversible, and was associated with increased nutrient intake as well as decreased internal ethanol levels. Inhibition of serotonergic neuron function using multiple independent genetic manipulations blocked the effect of yeast supplementation on ethanol sedation, nutrient intake, and internal ethanol levels. Our results demonstrate that yeast is a critical dietary component that influences ethanol sedation in flies and that serotonergic signaling is required for the effect of dietary yeast on nutrient intake, ethanol uptake/elimination, and ethanol sedation. Our studies establish the fly as a model for diet-induced changes in ethanol sedation and raise the possibility that serotonin might mediate the effect of diet on alcohol-related behavior in other species.
Collapse
Affiliation(s)
- Rebecca E. Schmitt
- Department of Human and Molecular Genetics Virginia Commonwealth University Richmond VA USA
| | - Monica R. Messick
- Department of Human and Molecular Genetics Virginia Commonwealth University Richmond VA USA
| | - Brandon C. Shell
- Department of Human and Molecular Genetics Virginia Commonwealth University Richmond VA USA
| | - Ellyn K. Dunbar
- Department of Human and Molecular Genetics Virginia Commonwealth University Richmond VA USA
| | - Huai‐Fang Fang
- Department of Chemistry and Neuroscience Graduate Program University of Virginia Charlottesville VA USA
| | - Keith L. Shelton
- Department of Pharmacology and Toxicology Virginia Commonwealth University Richmond VA USA
| | - B. Jill Venton
- Department of Chemistry and Neuroscience Graduate Program University of Virginia Charlottesville VA USA
| | - Scott D. Pletcher
- Department of Molecular and Integrative Physiology and Geriatrics Center University of Michigan Ann Arbor MI USA
| | - Mike Grotewiel
- Department of Human and Molecular Genetics Virginia Commonwealth University Richmond VA USA
- Virginia Commonwealth University Alcohol Research Center Richmond VA USA
| |
Collapse
|
19
|
Cheung TP, Choe JY, Richmond JE, Kim H. BK channel density is regulated by endoplasmic reticulum associated degradation and influenced by the SKN-1A/NRF1 transcription factor. PLoS Genet 2020; 16:e1008829. [PMID: 32502151 PMCID: PMC7299407 DOI: 10.1371/journal.pgen.1008829] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 06/17/2020] [Accepted: 05/05/2020] [Indexed: 12/19/2022] Open
Abstract
Ion channels are present at specific levels within subcellular compartments of excitable cells. The regulation of ion channel trafficking and targeting is an effective way to control cell excitability. The BK channel is a calcium-activated potassium channel that serves as a negative feedback mechanism at presynaptic axon terminals and sites of muscle excitation. The C. elegans BK channel ortholog, SLO-1, requires an endoplasmic reticulum (ER) membrane protein for efficient anterograde transport to these locations. Here, we found that, in the absence of this ER membrane protein, SLO-1 channels that are seemingly normally folded and expressed at physiological levels undergo SEL-11/HRD1-mediated ER-associated degradation (ERAD). This SLO-1 degradation is also indirectly regulated by a SKN-1A/NRF1-mediated transcriptional mechanism that controls proteasome levels. Therefore, our data indicate that SLO-1 channel density is regulated by the competitive balance between the efficiency of ER trafficking machinery and the capacity of ERAD. Excitable cells, such as neurons and muscles, are essential for the movement and behavior of animals. These cells express a set of specific types of ion channels that allow the selective passage of ions across the plasma membrane. The alteration in the levels of these ion channels influences cell excitability and the function of excitable cells. The regulation of ion channel trafficking and targeting is an effective way to control the function of excitable cells. The BK SLO-1 channel is a calcium-activated potassium channel that reduces excitability at presynaptic axon terminals and sites of muscle excitation. In a C. elegans genetic study, authors found that the delayed exit of SLO-1 channels from the ER causes their degradation by a mechanism called ER-associated degradation (ERAD). Interestingly, the same components that directly mediate SLO-1 ERAD also process a key transcriptional factor that maintains proteasome levels, thus indirectly influencing SLO-1 degradation. These data show that the levels of SLO-1 channels are regulated by the competitive balance between the efficiency of ER trafficking machinery and the capacity of ERAD.
Collapse
Affiliation(s)
- Timothy P. Cheung
- Center for Cancer Cell Biology, Immunology, and Infection, Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine & Science, North Chicago, Illinois, United States of America
- School of Graduate & Postdoctoral Studies, Rosalind Franklin University of Medicine & Science, North Chicago, Illinois, United States of America
| | - Jun-Yong Choe
- School of Graduate & Postdoctoral Studies, Rosalind Franklin University of Medicine & Science, North Chicago, Illinois, United States of America
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine & Science, North Chicago, Illinois United States of America
| | - Janet E. Richmond
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Hongkyun Kim
- Center for Cancer Cell Biology, Immunology, and Infection, Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine & Science, North Chicago, Illinois, United States of America
- School of Graduate & Postdoctoral Studies, Rosalind Franklin University of Medicine & Science, North Chicago, Illinois, United States of America
- * E-mail:
| |
Collapse
|
20
|
Thompson A, Cook J, Choquet H, Jorgenson E, Yin J, Kinnunen T, Barclay J, Morris AP, Pirmohamed M. Functional validity, role, and implications of heavy alcohol consumption genetic loci. SCIENCE ADVANCES 2020; 6:eaay5034. [PMID: 31998841 PMCID: PMC6962045 DOI: 10.1126/sciadv.aay5034] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 11/11/2019] [Indexed: 06/10/2023]
Abstract
High alcohol consumption is a risk factor for morbidity and mortality, yet few genetic loci have been robustly associated with alcohol intake. Here, we use U.K. Biobank (n = 125,249) and GERA (n = 47,967) datasets to determine genetic factors associated with extreme population-level alcohol consumption and examine the functional validity of outcomes using model organisms and in silico techniques. We identified six loci attaining genome-wide significant association with alcohol consumption after meta-analysis and meeting our criteria for replication: ADH1B (lead SNP: rs1229984), KLB (rs13130794), BTF3P13 (rs144198753), GCKR (rs1260326), SLC39A8 (rs13107325), and DRD2 (rs11214609). A conserved role in phenotypic responses to alcohol was observed for all genetic targets available for investigation (ADH1B, GCKR, SLC39A8, and KLB) in Caenorhabditis elegans. Evidence of causal links to lung cancer, and shared genetic architecture with gout and hypertension was also found. These findings offer insight into genes, pathways, and relationships for disease risk associated with high alcohol consumption.
Collapse
Affiliation(s)
- Andrew Thompson
- Wolfson Centre for Personalised Medicine, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
- MRC Centre for Drug Safety Science, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
- Liverpool Centre for Alcohol Research University of Liverpool, Liverpool, UK
| | - James Cook
- Biostatistics, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Hélène Choquet
- Division of Research, Kaiser Permanente Northern California, Oakland, CA 94612, USA
| | - Eric Jorgenson
- Division of Research, Kaiser Permanente Northern California, Oakland, CA 94612, USA
| | - Jie Yin
- Division of Research, Kaiser Permanente Northern California, Oakland, CA 94612, USA
| | - Tarja Kinnunen
- Department of Biological and Geographical Sciences, School of Applied Sciences, University of Huddersfield, Huddersfield, UK
| | - Jeff Barclay
- Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Andrew P. Morris
- Biostatistics, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Munir Pirmohamed
- Wolfson Centre for Personalised Medicine, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
- MRC Centre for Drug Safety Science, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
- Liverpool Centre for Alcohol Research University of Liverpool, Liverpool, UK
| |
Collapse
|
21
|
Scholz H. Unraveling the Mechanisms of Behaviors Associated With AUDs Using Flies and Worms. Alcohol Clin Exp Res 2019; 43:2274-2284. [PMID: 31529787 DOI: 10.1111/acer.14199] [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: 07/30/2019] [Accepted: 09/11/2019] [Indexed: 12/11/2022]
Abstract
Alcohol use disorders (AUDs) are very common worldwide and negatively affect both individuals and societies. To understand how normal behavior turns into uncontrollable use of alcohol, several approaches have been utilized in the last decades. However, we still do not completely understand how AUDs evolve or how they are maintained in the brains of affected individuals. In addition, efficient and effective treatment is still in need of development. This review focuses on alternative approaches developed over the last 20 years using Drosophila melanogaster (Drosophila) and Caenorhabditis elegans (C. elegans) as genetic model systems to determine the mechanisms underlying the action of ethanol (EtOH) and behaviors associated with AUDs. All the results and insights of studies over the last 20 years cannot be comprehensively summarized. Thus, a few prominent examples are provided highlighting the principles of the genes and mechanisms that have been uncovered and are involved in the action of EtOH at the cellular level. In addition, examples are provided of the genes and mechanisms that regulate behaviors relevant to acquiring and maintaining excessive alcohol intake, such as decision making, reward and withdrawal, and/or relapse regulation. How the insight gained from the results of Drosophila and C. elegans models can be translated to higher organisms, such as rodents and/or humans, is discussed, as well as whether these insights have any relevance or impact on our understanding of the mechanisms underlying AUDs in humans. Finally, future directions are presented that might facilitate the identification of drugs to treat AUDs.
Collapse
Affiliation(s)
- Henrike Scholz
- From the, Department of Biology, Institute for Zoology, Albertus-Magnus University of Cologne, Cologne, Germany
| |
Collapse
|
22
|
BK channel clustering is required for normal behavioral alcohol sensitivity in C. elegans. Sci Rep 2019; 9:10224. [PMID: 31308408 PMCID: PMC6629859 DOI: 10.1038/s41598-019-46615-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 07/02/2019] [Indexed: 02/05/2023] Open
Abstract
The large conductance, calcium- and voltage-activated potassium channel, known as the BK channel, is one of the central proteins that mediate alcohol intoxication and tolerance across species. Although ethanol targets BK channels through direct interaction, how ethanol-mediated BK channel activation causes behavioral intoxication is poorly understood. In. C. elegans, loss of function in SLO-1, the BK channel ortholog, confers profound ethanol resistance in movement and egg-laying behaviors. Here, we show that depletion of SLO-1 channels clustered at the active zones with no change in the overall channel expression level results in locomotory resistance to the intoxicating effect of ethanol, equivalent to that of slo-1 loss-of-function mutants. Likewise, depletion of clustered SLO-1 channels in the sarcolemma and neurons leads to ethanol-resistant egg-laying behavior. By contrast, reduction in the overall SLO-1 channel level by over 70% causes only moderate ethanol resistance in movement, and minimal, if any, resistance in egg laying. Our findings strongly suggest that behavioral ethanol sensitivity is conferred by local, but not global, depression of excitability via clustered BK channels. Given that clustered BK channels are functionally coupled to, and localize near, calcium channels, ethanol may mediate its behavioral effects by targeting BK channels and their coupled calcium channels.
Collapse
|
23
|
Katner SN, Bredhold KE, Steagall KB, Bell RL, Neal-Beliveau BS, Cheong MC, Engleman EA. Caenorhabditis elegans as a model system to identify therapeutics for alcohol use disorders. Behav Brain Res 2019; 365:7-16. [PMID: 30802531 DOI: 10.1016/j.bbr.2019.02.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 01/15/2019] [Accepted: 02/10/2019] [Indexed: 02/04/2023]
Abstract
Alcohol use disorders (AUDs) cause serious problems in society and few effective treatments are available. Caenorhabditis elegans (C. elegans) is an excellent invertebrate model to study the neurobiological basis of human behavior with a conserved, fully tractable genome, and a short generation time for fast generation of data at a fraction of the cost of other organisms. C. elegans demonstrate movement toward, and concentration-dependent self-exposure to various psychoactive drugs. The discovery of opioid receptors in C. elegans provided the impetus to test the hypothesis that C. elegans may be used as a medications screen to identify new AUD treatments. We tested the effects of naltrexone, an opioid antagonist and effective treatment for AUDs, on EtOH preference in C. elegans. Six-well agar test plates were prepared with EtOH placed in a target zone on one side and water in the opposite target zone of each well. Worms were treated with naltrexone before EtOH preference testing and then placed in the center of each well. Wild-type worms exhibited a concentration-dependent preference for 50, 70 and 95% EtOH. Naltrexone blocked acute EtOH preference, but had no effect on attraction to food or benzaldehyde in wild-type worms. Npr-17 opioid receptor knockout mutants did not display a preference for EtOH. In contrast, npr-17 opioid receptor rescue mutants exhibited significant EtOH preference behavior, which was attenuated by naltrexone. Chronic EtOH exposure induced treatment resistance and compulsive-like behavior. These data indicate that C. elegans can serve as a model system to identify compounds to treat AUDs.
Collapse
Affiliation(s)
- Simon N Katner
- Department of Psychiatry & Institute of Psychiatric Research, Indianapolis, IN, 46202, USA.
| | | | - Kevin B Steagall
- Department of Psychiatry & Institute of Psychiatric Research, Indianapolis, IN, 46202, USA
| | - Richard L Bell
- Department of Psychiatry & Institute of Psychiatric Research, Indianapolis, IN, 46202, USA
| | | | - Mi C Cheong
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, 75390, USA
| | - Eric A Engleman
- Department of Psychiatry & Institute of Psychiatric Research, Indianapolis, IN, 46202, USA
| |
Collapse
|
24
|
Morel C, Montgomery S, Han MH. Nicotine and alcohol: the role of midbrain dopaminergic neurons in drug reinforcement. Eur J Neurosci 2018; 50:2180-2200. [PMID: 30251377 DOI: 10.1111/ejn.14160] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 07/31/2018] [Accepted: 08/20/2018] [Indexed: 12/11/2022]
Abstract
Nicotine and alcohol addiction are leading causes of preventable death worldwide and continue to constitute a huge socio-economic burden. Both nicotine and alcohol perturb the brain's mesocorticolimbic system. Dopamine (DA) neurons projecting from the ventral tegmental area (VTA) to multiple downstream structures, including the nucleus accumbens, prefrontal cortex, and amygdala, are highly involved in the maintenance of healthy brain function. VTA DA neurons play a crucial role in associative learning and reinforcement. Nicotine and alcohol usurp these functions, promoting reinforcement of drug taking behaviors. In this review, we will first describe how nicotine and alcohol individually affect VTA DA neurons by examining how drug exposure alters the heterogeneous VTA microcircuit and network-wide projections. We will also examine how coadministration or previous exposure to nicotine or alcohol may augment the reinforcing effects of the other. Additionally, this review briefly summarizes the role of VTA DA neurons in nicotine, alcohol, and their synergistic effects in reinforcement and also addresses the remaining questions related to the circuit-function specificity of the dopaminergic system in mediating nicotine/alcohol reinforcement and comorbidity.
Collapse
Affiliation(s)
- Carole Morel
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, Icahn Building Floor 12 Room 12-75B, 1425 Madison Ave, New York, NY 10029, USA.,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Center for Affective Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Sarah Montgomery
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, Icahn Building Floor 12 Room 12-75B, 1425 Madison Ave, New York, NY 10029, USA.,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Center for Affective Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ming-Hu Han
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, Icahn Building Floor 12 Room 12-75B, 1425 Madison Ave, New York, NY 10029, USA.,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Center for Affective Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| |
Collapse
|
25
|
Tang J, Youngentob SL, Glendinning JI. Postnatal Exposure to Ethanol Increases Its Oral Acceptability to Adolescent Rats. Chem Senses 2018; 43:655-664. [PMID: 30169758 DOI: 10.1093/chemse/bjy056] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The aversive flavor of ethanol limits intake by many consumers. We asked whether intermittent consumption of ethanol increases its oral acceptability, using rats as a model system. We focused on adolescent rats because they (like their human counterparts) have a higher risk for alcohol overconsumption than do adult rats following experience with the drug. We measured the impact of ethanol exposure on 1) the oral acceptability of ethanol and surrogates for its bitter (quinine) and sweet (sucrose) flavor components in brief-access lick tests and 2) responses of the glossopharyngeal (GL) taste nerve to oral stimulation with the same chemical stimuli. During the exposure period, the experimental rats had access to chow, water and 10% ethanol every other day for 16 days; the control rats had access to chow and water over the same time period. The experimental rats consumed 7-14 g/day of 10% ethanol across the exposure period. This ethanol consumption significantly increased the oral acceptability of 3%, 6% and 10% ethanol, but had no impact on the oral acceptability of quinine, sucrose or NaCl. The ethanol exposure also diminished responses of the GL nerve to oral stimulation with ethanol, but not quinine, sucrose or NaCl. Taken together, these findings indicate that ethanol consumption increases the oral acceptability of ethanol in adolescent rats and that this increased oral acceptability is mediated, at least in part, by an exposure-induced reduction in responsiveness of the peripheral taste system to ethanol per se, rather than its bitter and sweet flavor components.
Collapse
Affiliation(s)
- Joyce Tang
- Department of Biology, Program in Neuroscience and Behavior, Barnard College, Columbia University, New York, NY, USA
| | - Steven L Youngentob
- University of Tennessee Health Science Center, Memphis, TN, USA
- SUNY Developmental Exposure Ethanol Research Center, Binghamton University, Binghamton, NY, USA
| | - John I Glendinning
- Department of Biology, Program in Neuroscience and Behavior, Barnard College, Columbia University, New York, NY, USA
- SUNY Developmental Exposure Ethanol Research Center, Binghamton University, Binghamton, NY, USA
| |
Collapse
|
26
|
Engleman EA, Steagall KB, Bredhold KE, Breach M, Kline HL, Bell RL, Katner SN, Neal-Beliveau BS. Caenorhabditis elegans Show Preference for Stimulants and Potential as a Model Organism for Medications Screening. Front Physiol 2018; 9:1200. [PMID: 30214414 PMCID: PMC6125605 DOI: 10.3389/fphys.2018.01200] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 08/10/2018] [Indexed: 12/20/2022] Open
Abstract
The nematode Caenorhabditis elegans (C. elegans) is a popular invertebrate model organism to study neurobiological disease states. This is due in part to the intricate mapping of all neurons and synapses of the entire animal, the wide availability of mutant strains, and the genetic and molecular tools that can be used to manipulate the genome and gene expression. We have shown that, C. elegans develops a conditioned preference for cues that had previously been paired with either cocaine or methamphetamine exposure that is dependent on dopamine neurotransmission, similar to findings using place conditioning with rats and mice. In the current study, we show C. elegans also display a preference for, and self-exposure to, cocaine and nicotine. This substance of abuse (SOA) preference response can be selectively blocked by pretreatment with naltrexone and is consistent with the recent discovery of an opioid receptor system in C. elegans. In addition, pre-exposure to the smoking cessation treatment varenicline also inhibits self-exposure to nicotine. Exposure to concentrations of treatments that inhibit SOA preference/self-exposure did not induce any significant inhibition of locomotor activity or affect food or benzaldehyde chemotaxis. These data provide predictive validity for the development of high-throughput C. elegans behavioral medication screens. These screens could enable fast and accurate generation of data to identify compounds that may be effective in treating human addiction. The successful development and validation of such models would introduce powerful and novel tools in the search for new pharmacological treatments for substance use disorders, and provide a platform to study the mechanisms that underlie addictions.
Collapse
Affiliation(s)
- Eric A Engleman
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Kevin B Steagall
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Kristin E Bredhold
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Michaela Breach
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Hannah L Kline
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Richard L Bell
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Simon N Katner
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Bethany S Neal-Beliveau
- Department of Psychology, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN, United States
| |
Collapse
|
27
|
Scott LL, Iyer S, Philpo AE, Avalos MN, Wu NS, Shi T, Prakash BA, Nguyen TT, Mihic SJ, Aldrich RW, Pierce JT. A Novel Peptide Restricts Ethanol Modulation of the BK Channel In Vitro and In Vivo. J Pharmacol Exp Ther 2018; 367:282-290. [PMID: 30158242 DOI: 10.1124/jpet.118.251918] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 08/20/2018] [Indexed: 12/13/2022] Open
Abstract
Alcohol is a widely used and abused substance. A major unresolved issue in the alcohol research field is determining which of the many alcohol target proteins identified to date is responsible for shaping each specific alcohol-related behavior. The large-conductance, calcium- and voltage-activated potassium channel (BK channel) is a conserved target of ethanol. Genetic manipulation of the highly conserved BKα channel influences alcohol-related behaviors across phylogenetically diverse species that include worm, fly, mouse, and man. A pharmacological tool that prevents alcohol's action at a single target, like the BK channel, would complement genetic approaches in the quest to define the behavioral consequences of alcohol at each target. To identify agents that specifically modulate the action of ethanol at the BK channel, we executed a high-throughput phagemid-display screen in combination with a Caenorhabditis elegans behavioral genetics assay. This screen selected a novel nonapeptide, LS10, which moderated acute ethanol intoxication in a BK channel-humanized C. elegans strain without altering basal behavior. LS10's action in vivo was dependent upon BK channel functional activity. Single-channel electrophysiological recordings in vitro showed that preincubation with a submicromolar concentration of LS10 restricted ethanol-induced changes in human BKα channel gating. In contrast, no substantial changes in basal human BKα channel function were observed after LS10 application. The results obtained with the LS10 peptide provide proof-of-concept evidence that a combined phagemid-display/behavioral genetics screening approach can provide novel tools for understanding the action of alcohol at the BK channel and how this, in turn, exerts influence over central nervous system function.
Collapse
Affiliation(s)
- Luisa L Scott
- Waggoner Center for Alcohol and Addiction Research (L.L.S., S.I., A.E.P., M.N.A., N.S.W., T.S., B.A.P., T.-T.N., S.J.M., R.W.A., J.T.P.), Department of Neuroscience (S.J.M., R.W.A., J.T.P.), and Center for Learning and Memory (R.W.A., J.T.P.), The University of Texas at Austin, Austin, Texas
| | - Sangeetha Iyer
- Waggoner Center for Alcohol and Addiction Research (L.L.S., S.I., A.E.P., M.N.A., N.S.W., T.S., B.A.P., T.-T.N., S.J.M., R.W.A., J.T.P.), Department of Neuroscience (S.J.M., R.W.A., J.T.P.), and Center for Learning and Memory (R.W.A., J.T.P.), The University of Texas at Austin, Austin, Texas
| | - Ashley E Philpo
- Waggoner Center for Alcohol and Addiction Research (L.L.S., S.I., A.E.P., M.N.A., N.S.W., T.S., B.A.P., T.-T.N., S.J.M., R.W.A., J.T.P.), Department of Neuroscience (S.J.M., R.W.A., J.T.P.), and Center for Learning and Memory (R.W.A., J.T.P.), The University of Texas at Austin, Austin, Texas
| | - Melva N Avalos
- Waggoner Center for Alcohol and Addiction Research (L.L.S., S.I., A.E.P., M.N.A., N.S.W., T.S., B.A.P., T.-T.N., S.J.M., R.W.A., J.T.P.), Department of Neuroscience (S.J.M., R.W.A., J.T.P.), and Center for Learning and Memory (R.W.A., J.T.P.), The University of Texas at Austin, Austin, Texas
| | - Natalie S Wu
- Waggoner Center for Alcohol and Addiction Research (L.L.S., S.I., A.E.P., M.N.A., N.S.W., T.S., B.A.P., T.-T.N., S.J.M., R.W.A., J.T.P.), Department of Neuroscience (S.J.M., R.W.A., J.T.P.), and Center for Learning and Memory (R.W.A., J.T.P.), The University of Texas at Austin, Austin, Texas
| | - Ted Shi
- Waggoner Center for Alcohol and Addiction Research (L.L.S., S.I., A.E.P., M.N.A., N.S.W., T.S., B.A.P., T.-T.N., S.J.M., R.W.A., J.T.P.), Department of Neuroscience (S.J.M., R.W.A., J.T.P.), and Center for Learning and Memory (R.W.A., J.T.P.), The University of Texas at Austin, Austin, Texas
| | - Brooke A Prakash
- Waggoner Center for Alcohol and Addiction Research (L.L.S., S.I., A.E.P., M.N.A., N.S.W., T.S., B.A.P., T.-T.N., S.J.M., R.W.A., J.T.P.), Department of Neuroscience (S.J.M., R.W.A., J.T.P.), and Center for Learning and Memory (R.W.A., J.T.P.), The University of Texas at Austin, Austin, Texas
| | - Thanh-Tu Nguyen
- Waggoner Center for Alcohol and Addiction Research (L.L.S., S.I., A.E.P., M.N.A., N.S.W., T.S., B.A.P., T.-T.N., S.J.M., R.W.A., J.T.P.), Department of Neuroscience (S.J.M., R.W.A., J.T.P.), and Center for Learning and Memory (R.W.A., J.T.P.), The University of Texas at Austin, Austin, Texas
| | - S John Mihic
- Waggoner Center for Alcohol and Addiction Research (L.L.S., S.I., A.E.P., M.N.A., N.S.W., T.S., B.A.P., T.-T.N., S.J.M., R.W.A., J.T.P.), Department of Neuroscience (S.J.M., R.W.A., J.T.P.), and Center for Learning and Memory (R.W.A., J.T.P.), The University of Texas at Austin, Austin, Texas
| | - Richard W Aldrich
- Waggoner Center for Alcohol and Addiction Research (L.L.S., S.I., A.E.P., M.N.A., N.S.W., T.S., B.A.P., T.-T.N., S.J.M., R.W.A., J.T.P.), Department of Neuroscience (S.J.M., R.W.A., J.T.P.), and Center for Learning and Memory (R.W.A., J.T.P.), The University of Texas at Austin, Austin, Texas
| | - Jonathan T Pierce
- Waggoner Center for Alcohol and Addiction Research (L.L.S., S.I., A.E.P., M.N.A., N.S.W., T.S., B.A.P., T.-T.N., S.J.M., R.W.A., J.T.P.), Department of Neuroscience (S.J.M., R.W.A., J.T.P.), and Center for Learning and Memory (R.W.A., J.T.P.), The University of Texas at Austin, Austin, Texas
| |
Collapse
|
28
|
Small molecule modulators of σ2R/Tmem97 reduce alcohol withdrawal-induced behaviors. Neuropsychopharmacology 2018; 43:1867-1875. [PMID: 29728649 PMCID: PMC6046036 DOI: 10.1038/s41386-018-0067-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 03/09/2018] [Accepted: 04/05/2018] [Indexed: 12/29/2022]
Abstract
Repeated cycles of intoxication and withdrawal enhance the negative reinforcing properties of alcohol and lead to neuroadaptations that underlie withdrawal symptoms driving alcohol dependence. Pharmacotherapies that target these neuroadaptations may help break the cycle of dependence. The sigma-1 receptor (σ1R) subtype has attracted interest as a possible modulator of the rewarding and reinforcing effects of alcohol. However, whether the sigma-2 receptor, recently cloned and identified as transmembrane protein 97 (σ2R/TMEM97), plays a role in alcohol-related behaviors is currently unknown. Using a Caenorhabditis elegans model, we identified two novel, selective σ2R/Tmem97 modulators that reduce alcohol withdrawal behavior via an ortholog of σ2R/TMEM97. We then show that one of these compounds blunted withdrawal-induced excessive alcohol drinking in a well-established rodent model of alcohol dependence. These discoveries provide the first evidence that σ2R/TMEM97 is involved in alcohol withdrawal behaviors and that this receptor is a potential new target for treating alcohol use disorder.
Collapse
|
29
|
Pierce JT. Calnexin revealed as an ether-a-go-go chaperone by getting mutant worms up and going. J Gen Physiol 2018; 150:1059-1061. [PMID: 29970410 PMCID: PMC6080892 DOI: 10.1085/jgp.201812068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Pierce examines new work revealing that calnexin controls the biogenesis of ERG-type K+ channels in Caenorhabditis elegans. The role of ion channels in cell excitability was first revealed in a series of voltage clamp experiments by Hodgkin and Huxley in the 1950s. However, it was not until the 1970s that patch-clamp recording ushered in a revolution that allowed physiologists to witness how ion channels flicker open and closed at angstrom scale and with microsecond resolution. The unexpectedly tight seal made by the patch pipette in the whole-cell configuration later allowed molecular biologists to suck up the insides of identified cells to unveil their unique molecular contents. By refining these techniques, researchers have scrutinized the surface and contents of excitable cells in detail over the past few decades. However, these powerful approaches do not discern which molecules are responsible for the dynamic control of the genesis, abundance, and subcellular localization of ion channels. In this dark territory, teams of unknown and poorly understood molecules guide specific ion channels through translation, folding, and modification, and then they shuttle them toward and away from distinct membrane domains via different subcellular routes. A central challenge in understanding these processes is the likelihood that these diverse regulatory molecules may be specific to ion channel subtypes, cell types, and circumstance. In work described in this issue, Bai et al. (2018. J. Gen. Physiol.https://doi.org/10.1085/jgp.201812025) begin to shed light on the biogenesis of UNC-103, a K+ channel found in Caenorhabditis elegans.
Collapse
Affiliation(s)
- Jonathan T Pierce
- Institute for Neuroscience, Institute for Cellular and Molecular Biology, Center for Learning and Memory, Waggoner Center for Alcohol and Addiction Research, Department of Neuroscience, The University of Texas at Austin, Austin, TX
| |
Collapse
|
30
|
Hughes V, Richardson MJE, Wall MJ. Acute ethanol exposure has bidirectional actions on the endogenous neuromodulator adenosine in rat hippocampus. Br J Pharmacol 2018; 175:1471-1485. [PMID: 29361192 PMCID: PMC5901169 DOI: 10.1111/bph.14152] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/19/2017] [Accepted: 12/25/2017] [Indexed: 02/07/2023] Open
Abstract
Background and Purpose Ethanol is a widely used recreational drug with complex effects on physiological and pathological brain function. In epileptic patients, the use of ethanol can modify seizure initiation and subsequent seizure activity with reports of ethanol being both pro‐ and anticonvulsant. One proposed target of ethanol's actions is the neuromodulator adenosine, which is released during epileptic seizures to feedback and inhibit the occurrence of subsequent seizures. Here, we investigated the actions of acute ethanol exposure on adenosine signalling in rat hippocampus. Experimental Approach We have combined electrophysiology with direct measurements of extracellular adenosine using microelectrode biosensors in rat hippocampal slices. Key Results We found that ethanol has bidirectional actions on adenosine signalling: depressant concentrations of ethanol (50 mM) increased the basal extracellular concentration of adenosine under baseline conditions, leading to the inhibition of synaptic transmission, but it inhibited adenosine release during evoked seizure activity in brain slices. The reduction in activity‐dependent adenosine release was in part produced by effects on NMDA receptors, although other mechanisms also appeared to be involved. Low concentrations of ethanol (10–15 mM) enhanced pathological network activity by selectively blocking activity‐dependent adenosine release. Conclusions and Implications The complex dose‐dependent actions of ethanol on adenosine signalling could in part explain the mixture of pro‐convulsant and anticonvulsant actions of ethanol that have previously been reported.
Collapse
Affiliation(s)
- Victoria Hughes
- School of Life Sciences, University of Warwick, Coventry, UK
| | | | - Mark J Wall
- School of Life Sciences, University of Warwick, Coventry, UK
| |
Collapse
|
31
|
Abrahao KP, Salinas AG, Lovinger DM. Alcohol and the Brain: Neuronal Molecular Targets, Synapses, and Circuits. Neuron 2017; 96:1223-1238. [PMID: 29268093 PMCID: PMC6566861 DOI: 10.1016/j.neuron.2017.10.032] [Citation(s) in RCA: 243] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 09/30/2017] [Accepted: 10/27/2017] [Indexed: 12/13/2022]
Abstract
Ethanol is one of the most commonly abused drugs. Although environmental and genetic factors contribute to the etiology of alcohol use disorders, it is ethanol's actions in the brain that explain (1) acute ethanol-related behavioral changes, such as stimulant followed by depressant effects, and (2) chronic changes in behavior, including escalated use, tolerance, compulsive seeking, and dependence. Our knowledge of ethanol use and abuse thus relies on understanding its effects on the brain. Scientists have employed both bottom-up and top-down approaches, building from molecular targets to behavioral analyses and vice versa, respectively. This review highlights current progress in the field, focusing on recent and emerging molecular, cellular, and circuit effects of the drug that impact ethanol-related behaviors. The focus of the field is now on pinpointing which molecular effects in specific neurons within a brain region contribute to behavioral changes across the course of acute and chronic ethanol exposure.
Collapse
Affiliation(s)
- Karina P Abrahao
- Laboratory for Integrative Neuroscience, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892, USA
| | - Armando G Salinas
- Laboratory for Integrative Neuroscience, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892, USA
| | - David M Lovinger
- Laboratory for Integrative Neuroscience, Division of Intramural Clinical and Biological Research, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892, USA.
| |
Collapse
|
32
|
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.
Collapse
|
33
|
Alcohol Regulates BK Surface Expression via Wnt/β-Catenin Signaling. J Neurosci 2017; 36:10625-10639. [PMID: 27733613 DOI: 10.1523/jneurosci.0491-16.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 07/27/2016] [Indexed: 12/26/2022] Open
Abstract
It has been suggested that drug tolerance represents a form of learning and memory, but this has not been experimentally established at the molecular level. We show that a component of alcohol molecular tolerance (channel internalization) from rat hippocampal neurons requires protein synthesis, in common with other forms of learning and memory. We identify β-catenin as a primary necessary protein. Alcohol increases β-catenin, and blocking accumulation of β-catenin blocks alcohol-induced internalization in these neurons. In transfected HEK293 cells, suppression of Wnt/β-catenin signaling blocks ethanol-induced internalization. Conversely, activation of Wnt/β-catenin reduces BK current density. A point mutation in a putative glycogen synthase kinase phosophorylation site within the S10 region of BK blocks internalization, suggesting that Wnt/β-catenin directly regulates alcohol-induced BK internalization via glycogen synthase kinase phosphorylation. These findings establish de novo protein synthesis and Wnt/β-catenin signaling as critical in mediating a persistent form of BK molecular alcohol tolerance establishing a commonality with other forms of long-term plasticity. SIGNIFICANCE STATEMENT Alcohol tolerance is a key step toward escalating alcohol consumption and subsequent dependence. Our research aims to make significant contributions toward novel, therapeutic approaches to prevent and treat alcohol misuse by understanding the molecular mechanisms of alcohol tolerance. In our current study, we identify the role of a key regulatory pathway in alcohol-induced persistent molecular changes within the hippocampus. The canonical Wnt/β-catenin pathway regulates BK channel surface expression in a protein synthesis-dependent manner reminiscent of other forms of long-term hippocampal neuronal adaptations. This unique insight opens the possibility of using clinically tested drugs, targeting the Wnt/β-catenin pathway, for the novel use of preventing and treating alcohol dependency.
Collapse
|
34
|
Behavioral Deficits Following Withdrawal from Chronic Ethanol Are Influenced by SLO Channel Function in Caenorhabditis elegans. Genetics 2017; 206:1445-1458. [PMID: 28546434 DOI: 10.1534/genetics.116.193102] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 04/29/2017] [Indexed: 01/03/2023] Open
Abstract
Symptoms of withdrawal from chronic alcohol use are a driving force for relapse in alcohol dependence. Thus, uncovering molecular targets to lessen their severity is key to breaking the cycle of dependence. Using the nematode Caenorhabditis elegans, we tested whether one highly conserved ethanol target, the large-conductance, calcium-activated potassium channel (known as the BK channel or Slo1), modulates ethanol withdrawal. Consistent with a previous report, we found that C. elegans displays withdrawal-related behavioral impairments after cessation of chronic ethanol exposure. We found that the degree of impairment is exacerbated in worms lacking the worm BK channel, SLO-1, and is reduced by selective rescue of this channel in the nervous system. Enhanced SLO-1 function, via gain-of-function mutation or overexpression, also dramatically reduced behavioral impairment during withdrawal. Consistent with these results, we found that chronic ethanol exposure decreased SLO-1 expression in a subset of neurons. In addition, we found that the function of a distinct, conserved Slo family channel, SLO-2, showed an inverse relationship to withdrawal behavior, and this influence depended on SLO-1 function. Together, our findings show that modulation of either Slo family ion channel bidirectionally regulates withdrawal behaviors in worm, supporting further exploration of the Slo family as targets for normalizing behaviors during alcohol withdrawal.
Collapse
|
35
|
Ethanol-Sensitive Pacemaker Neurons in the Mouse External Globus Pallidus. Neuropsychopharmacology 2017; 42:1070-1081. [PMID: 27827370 PMCID: PMC5506786 DOI: 10.1038/npp.2016.251] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 10/26/2016] [Accepted: 10/27/2016] [Indexed: 11/27/2022]
Abstract
Although ethanol is one of the most widely used drugs, we still lack a full understanding of which neuronal subtypes are affected by this drug. Pacemaker neurons exert powerful control over brain circuit function, but little is known about ethanol effects on these types of neurons. Neurons in the external globus pallidus (GPe) generate pacemaker activity that controls basal ganglia, circuitry associated with habitual and compulsive drug use. We performed patch-clamp recordings from GPe neurons and found that bath application of ethanol dose-dependently decreased the firing rate of low-frequency GPe neurons, but did not alter the firing of high-frequency neurons. GABA or glutamate receptor antagonists did not block the ethanol effect. The GPe is comprised of a heterogeneous population of neurons. We used Lhx6-EGFP and Npas1-tdTm mice strains to identify low-frequency neurons. Lhx6 and Npas1 neurons exhibited decreased firing with ethanol, but only Npas1 neurons were sensitive to 10 mM ethanol. Large-conductance voltage and Ca2+-activated K+ (BK) channel have a key role in the ethanol effect on GPe neurons, as the application of BK channel inhibitors blocked the ethanol-induced firing decrease. Ethanol also increased BK channel open probability measured in single-channel recordings from Npas1-tdTm neurons. In addition, in vivo electrophysiological recordings from GPe showed that ethanol decreased the firing of a large subset of low-frequency neurons. These findings indicate how selectivity of ethanol effects on pacemaker neurons can occur, and enhance our understanding of the mechanisms contributing to acute ethanol effects on the basal ganglia.
Collapse
|
36
|
Warden AS, Mayfield RD. Gene expression profiling in the human alcoholic brain. Neuropharmacology 2017; 122:161-174. [PMID: 28254370 DOI: 10.1016/j.neuropharm.2017.02.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 02/13/2017] [Accepted: 02/17/2017] [Indexed: 01/12/2023]
Abstract
Long-term alcohol use causes widespread changes in gene expression in the human brain. Aberrant gene expression changes likely contribute to the progression from occasional alcohol use to alcohol use disorder (including alcohol dependence). Transcriptome studies have identified individual gene candidates that are linked to alcohol-dependence phenotypes. The use of bioinformatics techniques to examine expression datasets has provided novel systems-level approaches to transcriptome profiling in human postmortem brain. These analytical advances, along with recent developments in next-generation sequencing technology, have been instrumental in detecting both known and novel coding and non-coding RNAs, alternative splicing events, and cell-type specific changes that may contribute to alcohol-related pathologies. This review offers an integrated perspective on alcohol-responsive transcriptional changes in the human brain underlying the regulatory gene networks that contribute to alcohol dependence. This article is part of the Special Issue entitled "Alcoholism".
Collapse
Affiliation(s)
- Anna S Warden
- Institute for Neuroscience, The University of Texas at Austin, 1 University Station, C7000, Austin, TX 78712, USA; Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, 2500 Speedway, A4800, Austin, TX 78712, USA
| | - R Dayne Mayfield
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, 2500 Speedway, A4800, Austin, TX 78712, USA.
| |
Collapse
|
37
|
Reilly MT, Noronha A, Goldman D, Koob GF. Genetic studies of alcohol dependence in the context of the addiction cycle. Neuropharmacology 2017; 122:3-21. [PMID: 28118990 DOI: 10.1016/j.neuropharm.2017.01.017] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/13/2017] [Accepted: 01/19/2017] [Indexed: 12/16/2022]
Abstract
Family, twin and adoption studies demonstrate clearly that alcohol dependence and alcohol use disorders are phenotypically complex and heritable. The heritability of alcohol use disorders is estimated at approximately 50-60% of the total phenotypic variability. Vulnerability to alcohol use disorders can be due to multiple genetic or environmental factors or their interaction which gives rise to extensive and daunting heterogeneity. This heterogeneity makes it a significant challenge in mapping and identifying the specific genes that influence alcohol use disorders. Genetic linkage and (candidate gene) association studies have been used now for decades to map and characterize genomic loci and genes that underlie the genetic vulnerability to alcohol use disorders. These approaches have been moderately successful in identifying several genes that contribute to the complexity of alcohol use disorders. Recently, genome-wide association studies have become one of the major tools for identifying genes for alcohol use disorders by examining correlations between millions of common single-nucleotide polymorphisms with diagnosis status. Genome-wide association studies are just beginning to uncover novel biology; however, the functional significance of results remains a matter of extensive debate and uncertainty. In this review, we present a select group of genome-wide association studies of alcohol dependence, as one example of a way to generate functional hypotheses, within the addiction cycle framework. This analysis may provide novel directions for validating the functional significance of alcohol dependence candidate genes. This article is part of the Special Issue entitled "Alcoholism".
Collapse
Affiliation(s)
- Matthew T Reilly
- National Institutes of Health (NIH), National Institute on Alcohol Abuse and Alcoholism (NIAAA), Division of Neuroscience and Behavior, 5635 Fishers Lane, Bethesda, MD 20852, USA.
| | - Antonio Noronha
- National Institutes of Health (NIH), National Institute on Alcohol Abuse and Alcoholism (NIAAA), Division of Neuroscience and Behavior, 5635 Fishers Lane, Bethesda, MD 20852, USA
| | - David Goldman
- National Institutes of Health (NIH), National Institute on Alcohol Abuse and Alcoholism (NIAAA), Chief, Laboratory of Neurogenetics, 5635 Fishers Lane, Bethesda, MD 20852, USA
| | - George F Koob
- National Institutes of Health (NIH), National Institute on Alcohol Abuse and Alcoholism (NIAAA), Director NIAAA, 5635 Fishers Lane, Bethesda, MD 20852, USA
| |
Collapse
|
38
|
Voltage-Sensitive Potassium Channels of the BK Type and Their Coding Genes Are Alcohol Targets in Neurons. Handb Exp Pharmacol 2017; 248:281-309. [PMID: 29204711 DOI: 10.1007/164_2017_78] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Among all members of the voltage-gated, TM6 ion channel superfamily, the proteins that constitute calcium- and voltage-gated potassium channels of large conductance (BK) and their coding genes are unique for their involvement in ethanol-induced disruption of normal physiology and behavior. Moreover, in vitro studies document that BK activity is modified by ethanol with an EC50~23 mM, which is near blood alcohol levels considered legal intoxication in most states of the USA (0.08 g/dL = 17.4 mM). Following a succinct introduction to our current understanding of BK structure and function in central neurons, with a focus on neural circuits that contribute to the neurobiology of alcohol use disorders (AUD), we review the modifications in organ physiology by alcohol exposure via BK and the different molecular elements that determine the ethanol response of BK in alcohol-naïve systems, including the role of an ethanol-recognizing site in the BK-forming slo1 protein, modulation of accessory BK subunits, and their coding genes. The participation of these and additional elements in determining the response of a system or an organism to protracted ethanol exposure is consequently analyzed, with insights obtained from invertebrate and vertebrate models. Particular emphasis is put on the role of BK and coding genes in different forms of tolerance to alcohol exposure. We finally discuss genetic results on BK obtained in invertebrate organisms and rodents in light of possible extrapolation to human AUD.
Collapse
|
39
|
Kuntamallappanavar G, Dopico AM. Alcohol modulation of BK channel gating depends on β subunit composition. J Gen Physiol 2016; 148:419-440. [PMID: 27799321 PMCID: PMC5089933 DOI: 10.1085/jgp.201611594] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 10/14/2016] [Indexed: 01/01/2023] Open
Abstract
In most mammalian tissues, Ca2+i/voltage-gated, large conductance K+ (BK) channels consist of channel-forming slo1 and auxiliary (β1-β4) subunits. When Ca2+i (3-20 µM) reaches the vicinity of BK channels and increases their activity at physiological voltages, β1- and β4-containing BK channels are, respectively, inhibited and potentiated by intoxicating levels of ethanol (50 mM). Previous studies using different slo1s, lipid environments, and Ca2+i concentrations-all determinants of the BK response to ethanol-made it impossible to determine the specific contribution of β subunits to ethanol action on BK activity. Furthermore, these studies measured ethanol action on ionic current under a limited range of stimuli, rendering no information on the gating processes targeted by alcohol and their regulation by βs. Here, we used identical experimental conditions to obtain single-channel and macroscopic currents of the same slo1 channel ("cbv1" from rat cerebral artery myocytes) in the presence and absence of 50 mM ethanol. First, we assessed the role five different β subunits (1,2,2-IR, 3-variant d, and 4) in ethanol action on channel function. Thus, two phenotypes were identified: (1) ethanol potentiated cbv1-, cbv1+β3-, and cbv1+β4-mediated currents at low Ca2+i while inhibiting current at high Ca2+i, the potentiation-inhibition crossover occurring at 20 µM Ca2+i; (2) for cbv1+β1, cbv1+wt β2, and cbv1+β2-IR, this crossover was shifted to ∼3 µM Ca2+i Second, applying Horrigan-Aldrich gating analysis on both phenotypes, we show that ethanol fails to modify intrinsic gating and the voltage-dependent parameters under examination. For cbv1, however, ethanol (a) drastically increases the channel's apparent Ca2+ affinity (nine-times decrease in Kd) and (b) very mildly decreases allosteric coupling between Ca2+ binding and channel opening (C). The decreased Kd leads to increased channel activity. For cbv1+β1, ethanol (a) also decreases Kd, yet this decrease (two times) is much smaller than that of cbv1; (b) reduces C; and (c) decreases coupling between Ca2+ binding and voltage sensing (parameter E). Decreased allosteric coupling leads to diminished BK activity. Thus, we have identified critical gating modifications that lead to the differential actions of ethanol on slo1 with and without different β subunits.
Collapse
Affiliation(s)
- Guruprasad Kuntamallappanavar
- Department of Pharmacology, College of Medicine, The University of Tennessee Health Science Center, Memphis, TN 38103
| | - Alex M Dopico
- Department of Pharmacology, College of Medicine, The University of Tennessee Health Science Center, Memphis, TN 38103
| |
Collapse
|
40
|
Cochet-Escartin O, Carter JA, Chakraverti-Wuerthwein M, Sinha J, Collins EMS. Slo1 regulates ethanol-induced scrunching in freshwater planarians. Phys Biol 2016; 13:055001. [DOI: 10.1088/1478-3975/13/5/055001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
41
|
Dopico AM, Bukiya AN, Kuntamallappanavar G, Liu J. Modulation of BK Channels by Ethanol. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 128:239-79. [PMID: 27238266 PMCID: PMC5257281 DOI: 10.1016/bs.irn.2016.03.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In alcohol-naïve systems, ethanol (<100mM) exposure of calcium-gated BK channels perturbs physiology and behavior. Brief (several minutes) ethanol exposure usually leads to increased BK current, which results from ethanol interaction with a pocket mapped to the BK channel-forming slo1 protein cytosolic tail domain. The importance of this region in ethanol-induced intoxication has been independently supported by an unbiased screen of Caenorhabditis elegans slo1 mutants. However, ethanol-induced BK activation is not universal as refractoriness and inhibition have been reported. The final effect depends on many factors, including intracellular calcium levels, slo1 isoform, BK beta subunit composition, posttranslational modification of BK proteins, channel lipid microenvironment, and type of ethanol administration. Studies in Drosophila melanogaster, C. elegans, and rodents show that protracted/repeated ethanol administration leads to tolerance to ethanol-induced modification of BK-driven physiology and behavior. Unveiling the mechanisms underlying tolerance is of major importance, as tolerance to ethanol has been proposed as predictor of risk for alcoholism.
Collapse
Affiliation(s)
- A M Dopico
- College of Medicine, The University of Tennessee Health Science Center, Memphis, TN, United States.
| | - A N Bukiya
- College of Medicine, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - G Kuntamallappanavar
- College of Medicine, The University of Tennessee Health Science Center, Memphis, TN, United States
| | - J Liu
- College of Medicine, The University of Tennessee Health Science Center, Memphis, TN, United States
| |
Collapse
|
42
|
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.
Collapse
|
43
|
Kreifeldt M, Cates-Gatto C, Roberts AJ, Contet C. BK Channel β1 Subunit Contributes to Behavioral Adaptations Elicited by Chronic Intermittent Ethanol Exposure. Alcohol Clin Exp Res 2015; 39:2394-402. [PMID: 26578345 DOI: 10.1111/acer.12911] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 09/16/2015] [Indexed: 11/30/2022]
Abstract
BACKGROUND Large conductance, calcium- and voltage-activated potassium (BK) channels regulate neuronal excitability and neurotransmission. They can be directly activated by ethanol (EtOH) and they may be implicated in EtOH dependence. In this study, we sought to determine the influence of the auxiliary β1 and β4 subunits on EtOH metabolism, acute sensitivity to EtOH intoxication, acute functional tolerance, chronic tolerance, and handling-induced convulsions during withdrawal. METHODS Motor coordination, righting reflex, and body temperature were evaluated in BK β1 and β4 knockout, heterozygous, and wild-type mice following acute EtOH administration. Chronic tolerance and physical dependence were induced by chronic intermittent inhalation of EtOH vapor. RESULTS Constitutive deficiency in BK β1 or β4 subunits did not alter the clearance rate of EtOH, acute sensitivity to EtOH-induced ataxia, sedation, and hypothermia, nor acute functional tolerance to ataxia. BK β1 deletion reduced chronic tolerance to sedation and abolished chronic tolerance to hypothermia, while BK β4 deletion did not affect these adaptations to chronic EtOH exposure. Finally, the absence of BK β1 accelerated the appearance, while the absence of BK β4 delayed the resolution, of the hyperexcitable state associated with EtOH withdrawal. CONCLUSIONS Altogether, the present findings reveal the critical role of BK β1 in behavioral adaptations to prolonged, repeated EtOH intoxication.
Collapse
Affiliation(s)
- Max Kreifeldt
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California
| | - Chelsea Cates-Gatto
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, California
| | - Amanda J Roberts
- Molecular and Cellular Neuroscience Department, The Scripps Research Institute, La Jolla, California
| | - Candice Contet
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California
| |
Collapse
|
44
|
Korpi ER, den Hollander B, Farooq U, Vashchinkina E, Rajkumar R, Nutt DJ, Hyytiä P, Dawe GS. Mechanisms of Action and Persistent Neuroplasticity by Drugs of Abuse. Pharmacol Rev 2015; 67:872-1004. [DOI: 10.1124/pr.115.010967] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
|
45
|
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.
Collapse
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
| |
Collapse
|
46
|
Dopico AM, Bukiya AN, Martin GE. Ethanol modulation of mammalian BK channels in excitable tissues: molecular targets and their possible contribution to alcohol-induced altered behavior. Front Physiol 2014; 5:466. [PMID: 25538625 PMCID: PMC4256990 DOI: 10.3389/fphys.2014.00466] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 11/13/2014] [Indexed: 11/30/2022] Open
Abstract
In most tissues, the function of Ca2+- and voltage-gated K+ (BK) channels is modified in response to ethanol concentrations reached in human blood during alcohol intoxication. In general, modification of BK current from ethanol-naïve preparations in response to brief ethanol exposure results from changes in channel open probability without modification of unitary conductance or change in BK protein levels in the membrane. Protracted and/or repeated ethanol exposure, however, may evoke changes in BK expression. The final ethanol effect on BK open probability leading to either BK current potentiation or BK current reduction is determined by an orchestration of molecular factors, including levels of activating ligand (Ca2+i), BK subunit composition and post-translational modifications, and the channel's lipid microenvironment. These factors seem to allosterically regulate a direct interaction between ethanol and a recognition pocket of discrete dimensions recently mapped to the channel-forming (slo1) subunit. Type of ethanol exposure also plays a role in the final BK response to the drug: in several central nervous system regions (e.g., striatum, primary sensory neurons, and supraoptic nucleus), acute exposure to ethanol reduces neuronal excitability by enhancing BK activity. In contrast, protracted or repetitive ethanol administration may alter BK subunit composition and membrane expression, rendering the BK complex insensitive to further ethanol exposure. In neurohypophyseal axon terminals, ethanol potentiation of BK channel activity leads to a reduction in neuropeptide release. In vascular smooth muscle, however, ethanol inhibition of BK current leads to cell contraction and vascular constriction.
Collapse
Affiliation(s)
- Alex M Dopico
- Department of Pharmacology, College of Medicine, The University of Tennessee Health Science Center Memphis, TN, USA
| | - Anna N Bukiya
- Department of Pharmacology, College of Medicine, The University of Tennessee Health Science Center Memphis, TN, USA
| | - Gilles E Martin
- Department of Psychiatry, The University of Massachusetts Medical School Worcester, MA, USA
| |
Collapse
|