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Mulholland PJ, Padula AE, Wilhelm LJ, Park B, Grant KA, Ferguson BM, Cervera-Juanes R. Cross-species epigenetic regulation of nucleus accumbens KCNN3 transcripts by excessive ethanol drinking. Transl Psychiatry 2023; 13:364. [PMID: 38012158 PMCID: PMC10682415 DOI: 10.1038/s41398-023-02676-z] [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: 11/07/2023] [Revised: 11/14/2023] [Accepted: 11/17/2023] [Indexed: 11/29/2023] Open
Abstract
The underlying genetic and epigenetic mechanisms driving functional adaptations in neuronal excitability and excessive alcohol intake are poorly understood. Small-conductance Ca2+-activated K+ (KCa2 or SK) channels encoded by the KCNN family of genes have emerged from preclinical studies as a key contributor to alcohol-induced functional neuroadaptations in alcohol-drinking monkeys and alcohol-dependent mice. Here, this cross-species analysis focused on KCNN3 DNA methylation, gene expression, and single nucleotide polymorphisms, including alternative promoters in KCNN3, that could influence surface trafficking and function of KCa2 channels. Bisulfite sequencing analysis of the nucleus accumbens tissue from alcohol-drinking monkeys and alcohol-dependent mice revealed a differentially methylated region in exon 1A of KCNN3 that overlaps with a predicted promoter sequence. The hypermethylation of KCNN3 in the accumbens paralleled an increase in the expression of alternative transcripts that encode apamin-insensitive and dominant-negative KCa2 channel isoforms. A polymorphic repeat in macaque KCNN3 encoded by exon 1 did not correlate with alcohol drinking. At the protein level, KCa2.3 channel expression in the accumbens was significantly reduced in very heavy-drinking monkeys. Together, our cross-species findings on epigenetic dysregulation of KCNN3 represent a complex mechanism that utilizes alternative promoters to potentially impact the firing of accumbens neurons. Thus, these results provide support for hypermethylation of KCNN3 as a possible key molecular mechanism underlying harmful alcohol intake and alcohol use disorder.
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Affiliation(s)
- Patrick J Mulholland
- Department of Neuroscience, Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Audrey E Padula
- Department of Neuroscience, Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Larry J Wilhelm
- Department of Translational Neuroscience, Atrium Health Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - Byung Park
- Department of Public Health and Preventive Medicine, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Kathleen A Grant
- Department of Neurosciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, 97006, USA
| | - Betsy M Ferguson
- Department of Neurosciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, 97006, USA
| | - Rita Cervera-Juanes
- Department of Translational Neuroscience, Atrium Health Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA.
- Center for Precision Medicine, Atrium Health Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA.
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2
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Mulholland PJ, Berto S, Wilmarth PA, McMahan C, Ball LE, Woodward JJ. Adaptor protein complex 2 in the orbitofrontal cortex predicts alcohol use disorder. Mol Psychiatry 2023; 28:4766-4776. [PMID: 37679472 PMCID: PMC10918038 DOI: 10.1038/s41380-023-02236-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/17/2023] [Accepted: 08/23/2023] [Indexed: 09/09/2023]
Abstract
Alcohol use disorder (AUD) is a life-threatening disease characterized by compulsive drinking, cognitive deficits, and social impairment that continue despite negative consequences. The inability of individuals with AUD to regulate drinking may involve functional deficits in cortical areas that normally balance actions that have aspects of both reward and risk. Among these, the orbitofrontal cortex (OFC) is critically involved in goal-directed behavior and is thought to maintain a representation of reward value that guides decision making. In the present study, we analyzed post-mortem OFC brain samples collected from age- and sex-matched control subjects and those with AUD using proteomics, bioinformatics, machine learning, and reverse genetics approaches. Of the 4,500+ total unique proteins identified in the proteomics screen, there were 47 proteins that differed significantly by sex that were enriched in processes regulating extracellular matrix and axonal structure. Gene ontology enrichment analysis revealed that proteins differentially expressed in AUD cases were involved in synaptic and mitochondrial function, as well as transmembrane transporter activity. Alcohol-sensitive OFC proteins also mapped to abnormal social behaviors and social interactions. Machine learning analysis of the post-mortem OFC proteome revealed dysregulation of presynaptic (e.g., AP2A1) and mitochondrial proteins that predicted the occurrence and severity of AUD. Using a reverse genetics approach to validate a target protein, we found that prefrontal Ap2a1 expression significantly correlated with voluntary alcohol drinking in male and female genetically diverse mouse strains. Moreover, recombinant inbred strains that inherited the C57BL/6J allele at the Ap2a1 interval consumed higher amounts of alcohol than those that inherited the DBA/2J allele. Together, these findings highlight the impact of excessive alcohol consumption on the human OFC proteome and identify important cross-species cortical mechanisms and proteins that control drinking in individuals with AUD.
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Affiliation(s)
- Patrick J Mulholland
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, 29425, USA.
- Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC, 29425, USA.
| | - Stefano Berto
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Phillip A Wilmarth
- Proteomics Shared Resource, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR, 97239, USA
| | - Christopher McMahan
- School of Mathematical and Statistical Sciences, Clemson-MUSC Artificial Intelligence Hub, Clemson University, Clemson, SC, 29634-0975, USA
| | - Lauren E Ball
- Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - John J Woodward
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, 29425, USA
- Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC, 29425, USA
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3
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Juanes RC, Mulholland P, Padula A, Wilhelm L, Park B, Grant K, Ferguson B. Cross-species epigenetic regulation of nucleus accumbens KCNN3 transcripts by excessive ethanol drinking. RESEARCH SQUARE 2023:rs.3.rs-3315122. [PMID: 37790552 PMCID: PMC10543433 DOI: 10.21203/rs.3.rs-3315122/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
The underlying genetic and epigenetic mechanisms driving functional adaptations in neuronal excitability and excessive alcohol intake are poorly understood. Small-conductance Ca2+-activated K+ (KCa2 or SK) channels encoded by the KCNN family of genes have emerged from preclinical studies as a key contributor to alcohol-induced functional neuroadaptations in alcohol-drinking monkeys and alcohol dependent mice. Here, this cross-species analysis focused on KCNN3 DNA methylation, gene expression, and single nucleotide polymorphisms including alternative promoters in KCNN3 that could influence surface trafficking and function of KCa2 channels. Bisulfite sequencing analysis of the nucleus accumbens tissue from alcohol-drinking monkeys and alcohol dependent mice revealed a differentially methylated region in exon 1A of KCNN3 that overlaps with a predicted promoter sequence. The hypermethylation of KCNN3 in the accumbens paralleled an increase in expression of alternative transcripts that encode apamin-insensitive and dominant-negative KCa2 channel isoforms. A polymorphic repeat in macaque KCNN3 encoded by exon 1 did not correlate with alcohol drinking. At the protein level, KCa2.3 channel expression in the accumbens was significantly reduced in very heavy drinking monkeys. Together, our cross-species findings on epigenetic dysregulation of KCNN3 represent a complex mechanism that utilizes alternative promoters to impact firing of accumbens neurons. Thus, these results provide support for hypermethylation of KCNN3 as a possible key molecular mechanism underlying harmful alcohol intake and alcohol use disorder.
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Affiliation(s)
| | | | | | | | | | | | - Betsy Ferguson
- Oregon Health & Sciences University/Oregon National Primate Research Center
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4
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Mulholland PJ, Berto S, Wilmarth PA, McMahan C, Ball LE, Woodward JJ. Adaptor protein complex 2 in the orbitofrontal cortex predicts alcohol use disorder. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.28.542637. [PMID: 37398482 PMCID: PMC10312445 DOI: 10.1101/2023.05.28.542637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Alcohol use disorder (AUD) is a life-threatening disease characterized by compulsive drinking, cognitive deficits, and social impairment that continue despite negative consequences. The inability of individuals with AUD to regulate drinking may involve functional deficits in cortical areas that normally balance actions that have aspects of both reward and risk. Among these, the orbitofrontal cortex (OFC) is critically involved in goal-directed behavior and is thought to maintain a representation of reward value that guides decision making. In the present study, we analyzed post-mortem OFC brain samples collected from age- and sex-matched control subjects and those with AUD using proteomics, bioinformatics, machine learning, and reverse genetics approaches. Of the 4,500+ total unique proteins identified in the proteomics screen, there were 47 proteins that differed significantly by sex that were enriched in processes regulating extracellular matrix and axonal structure. Gene ontology enrichment analysis revealed that proteins differentially expressed in AUD cases were involved in synaptic and mitochondrial function, as well as transmembrane transporter activity. Alcohol-sensitive OFC proteins also mapped to abnormal social behaviors and social interactions. Machine learning analysis of the post-mortem OFC proteome revealed dysregulation of presynaptic (e.g., AP2A1) and mitochondrial proteins that predicted the occurrence and severity of AUD. Using a reverse genetics approach to validate a target protein, we found that prefrontal Ap2a1 expression significantly correlated with voluntary alcohol drinking in male and female genetically diverse mouse strains. Moreover, recombinant inbred strains that inherited the C57BL/6J allele at the Ap2a1 interval consumed higher amounts of alcohol than those that inherited the DBA/2J allele. Together, these findings highlight the impact of excessive alcohol consumption on the human OFC proteome and identify important cross-species cortical mechanisms and proteins that control drinking in individuals with AUD.
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Mineur YS, Garcia-Rivas V, Thomas MA, Soares AR, McKee SA, Picciotto MR. Sex differences in stress-induced alcohol intake: a review of preclinical studies focused on amygdala and inflammatory pathways. Psychopharmacology (Berl) 2022; 239:2041-2061. [PMID: 35359158 PMCID: PMC9704113 DOI: 10.1007/s00213-022-06120-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 03/14/2022] [Indexed: 02/06/2023]
Abstract
Clinical studies suggest that women are more likely than men to relapse to alcohol drinking in response to stress; however, the mechanisms underlying this sex difference are not well understood. A number of preclinical behavioral models have been used to study stress-induced alcohol intake. Here, we review paradigms used to study effects of stress on alcohol intake in rodents, focusing on findings relevant to sex differences. To date, studies of sex differences in stress-induced alcohol drinking have been somewhat limited; however, there is evidence that amygdala-centered circuits contribute to effects of stress on alcohol seeking. In addition, we present an overview of inflammatory pathways leading to microglial activation that may contribute to alcohol-dependent behaviors. We propose that sex differences in neuronal function and inflammatory signaling in circuits centered on the amygdala are involved in sex-dependent effects on stress-induced alcohol seeking and suggest that this is an important area for future studies.
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Affiliation(s)
- Yann S Mineur
- Department of Psychiatry, Yale University, 34 Park Street, 3Rd Floor Research, New Haven, CT, 06508, USA
| | - Vernon Garcia-Rivas
- Department of Psychiatry, Yale University, 34 Park Street, 3Rd Floor Research, New Haven, CT, 06508, USA
| | - Merrilee A Thomas
- Department of Psychiatry, Yale University, 34 Park Street, 3Rd Floor Research, New Haven, CT, 06508, USA
| | - Alexa R Soares
- Department of Psychiatry, Yale University, 34 Park Street, 3Rd Floor Research, New Haven, CT, 06508, USA
- Yale Interdepartmental Neuroscience Program, New Haven, CT, USA
| | - Sherry A McKee
- Department of Psychiatry, Yale University, 34 Park Street, 3Rd Floor Research, New Haven, CT, 06508, USA
| | - Marina R Picciotto
- Department of Psychiatry, Yale University, 34 Park Street, 3Rd Floor Research, New Haven, CT, 06508, USA.
- Yale Interdepartmental Neuroscience Program, New Haven, CT, USA.
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Bloch S, Holleran KM, Kash TL, Vazey EM, Rinker JA, Lebonville CL, O'Hara K, Lopez MF, Jones SR, Grant KA, Becker HC, Mulholland PJ. Assessing negative affect in mice during abstinence from alcohol drinking: Limitations and future challenges. Alcohol 2022; 100:41-56. [PMID: 35181404 PMCID: PMC8983487 DOI: 10.1016/j.alcohol.2022.02.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 02/09/2022] [Accepted: 02/09/2022] [Indexed: 01/09/2023]
Abstract
Alcohol use disorder (AUD) is frequently comorbid with mood disorders, and these co-occurring neuropsychiatric disorders contribute to the development and maintenance of alcohol dependence and relapse. In preclinical models, mice chronically exposed to alcohol display anxiety-like and depressive-like behaviors during acute withdrawal and protracted abstinence. However, in total, results from studies using voluntary alcohol-drinking paradigms show variable behavioral outcomes in assays measuring negative affective behaviors. Thus, the main objective of this review is to summarize the literature on the variability of negative affective behaviors in mice after chronic alcohol exposure. We compare the behavioral phenotypes that emerge during abstinence across different exposure models, including models of alcohol and stress interactions. The complicated outcomes from these studies highlight the difficulties of assessing negative affective behaviors in mouse models designed for the study of AUD. We discuss new behavioral assays, comprehensive platforms, and unbiased machine-learning algorithms as promising approaches to better understand the interaction between alcohol and negative affect in mice. New data-driven approaches in the understanding of mouse behavior hold promise for improving the identification of mechanisms, cell subtypes, and neurocircuits that mediate negative affect. In turn, improving our understanding of the neurobehavioral basis of alcohol-associated negative affect will provide a platform to test hypotheses in mouse models that aim to improve the development of more effective strategies for treating individuals with AUD and co-occurring mood disorders.
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Affiliation(s)
- Solal Bloch
- Department of Neuroscience, Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC 29425, United States
| | - Katherine M Holleran
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27101, United States
| | - Thomas L Kash
- Bowles Center for Alcohol Studies, Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, United States
| | - Elena M Vazey
- Department of Biology, University of Massachusetts Amherst, Amherst, MA 01003, United States
| | - Jennifer A Rinker
- Department of Neuroscience, Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC 29425, United States
| | - Christina L Lebonville
- Department of Neuroscience, Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC 29425, United States
| | - Krysten O'Hara
- Department of Neuroscience, Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC 29425, United States
| | - Marcelo F Lopez
- Department of Psychiatry & Behavioral Sciences, Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC 29425, United States
| | - Sara R Jones
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27101, United States
| | - Kathleen A Grant
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR 97006, United States
| | - Howard C Becker
- Department of Psychiatry & Behavioral Sciences, Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC 29425, United States
| | - Patrick J Mulholland
- Department of Neuroscience, Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC 29425, United States.
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McCoy MT, Jayanthi S, Cadet JL. Potassium Channels and Their Potential Roles in Substance Use Disorders. Int J Mol Sci 2021; 22:1249. [PMID: 33513859 PMCID: PMC7865894 DOI: 10.3390/ijms22031249] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 01/12/2023] Open
Abstract
Substance use disorders (SUDs) are ubiquitous throughout the world. However, much remains to be done to develop pharmacotherapies that are very efficacious because the focus has been mostly on using dopaminergic agents or opioid agonists. Herein we discuss the potential of using potassium channel activators in SUD treatment because evidence has accumulated to support a role of these channels in the effects of rewarding drugs. Potassium channels regulate neuronal action potential via effects on threshold, burst firing, and firing frequency. They are located in brain regions identified as important for the behavioral responses to rewarding drugs. In addition, their expression profiles are influenced by administration of rewarding substances. Genetic studies have also implicated variants in genes that encode potassium channels. Importantly, administration of potassium agonists have been shown to reduce alcohol intake and to augment the behavioral effects of opioid drugs. Potassium channel expression is also increased in animals with reduced intake of methamphetamine. Together, these results support the idea of further investing in studies that focus on elucidating the role of potassium channels as targets for therapeutic interventions against SUDs.
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Affiliation(s)
| | | | - Jean Lud Cadet
- Molecular Neuropsychiatry Research Branch, NIDA Intramural Research Program, Baltimore, MD 21224, USA; (M.T.M.); (S.J.)
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