51
|
Arnold PR, Wells AD, Li XC. Diversity and Emerging Roles of Enhancer RNA in Regulation of Gene Expression and Cell Fate. Front Cell Dev Biol 2020; 7:377. [PMID: 31993419 PMCID: PMC6971116 DOI: 10.3389/fcell.2019.00377] [Citation(s) in RCA: 120] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/17/2019] [Indexed: 12/27/2022] Open
Abstract
Enhancers are cis-regulatory elements in the genome that cooperate with promoters to control target gene transcription. Unlike promoters, enhancers are not necessarily adjacent to target genes and can exert their functions regardless of enhancer orientations, positions and spatial segregations from target genes. Thus, for a long time, the question as to how enhancers act in a temporal and spatial manner attracted considerable attention. The recent discovery that enhancers are also abundantly transcribed raises interesting questions about the exact roles of enhancer RNA (eRNA) in gene regulation. In this review, we highlight the process of enhancer transcription and the diverse features of eRNA. We review eRNA functions, which include enhancer-promoter looping, chromatin modifying, and transcription regulating. As eRNA are transcribed from active enhancers, they exhibit tissue and lineage specificity, and serve as markers of cell state and function. Finally, we discuss the unique relationship between eRNA and super enhancers in phase separation wherein eRNA may contribute significantly to cell fate decisions.
Collapse
Affiliation(s)
- Preston R Arnold
- Texas A&M Health Science Center, College of Medicine, Bryan, TX, United States.,Immunobiology and Transplant Sciences, Department of Surgery, Houston Methodist Hospital, Houston, TX, United States
| | - Andrew D Wells
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Xian C Li
- Immunobiology and Transplant Sciences, Department of Surgery, Houston Methodist Hospital, Houston, TX, United States
| |
Collapse
|
52
|
MicroRNA-137 Drives Epigenetic Reprogramming in the Adult Amygdala and Behavioral Changes after Adolescent Alcohol Exposure. eNeuro 2019; 6:ENEURO.0401-19.2019. [PMID: 31740576 PMCID: PMC6917896 DOI: 10.1523/eneuro.0401-19.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 10/22/2019] [Indexed: 12/20/2022] Open
Abstract
Adolescent binge drinking is a serious public health concern and a risk factor for alcohol use disorder (AUD) and comorbid anxiety in adulthood. Chromatin remodeling mediated by epigenetic enzymes including lysine-specific demethylase 1 (LSD1) due to adolescent alcohol exposure may play a role in adult psychopathology. The mechanism by which adolescent alcohol exposure mechanistically regulates epigenetic reprogramming and behavioral changes in adulthood is unknown. We investigated the role of microRNA-137 (miR-137), which is crucial for normal neurodevelopment and targets LSD1, in adolescent intermittent ethanol (AIE) exposure-induced anxiety-like and alcohol-drinking behaviors and related epigenetic reprogramming in the amygdala in adulthood. Adolescent rats were exposed to 2 g/kg ethanol (2 d on/off; AIE) or adolescent intermittent saline (AIS) during postnatal days (PND)28-PND41 and allowed to grow to adulthood for analysis of behavior, miRNA expression, and epigenetic measures in the amygdala. Interestingly, miR-137 was increased and its target genes Lsd1 and Lsd1 + 8a were decreased in the AIE adult amygdala. Infusion of miR-137 antagomir directly into the central nucleus of the amygdala (CeA) rescues AIE-induced alcohol-drinking and anxiety-like behaviors via normalization of decreased Lsd1 expression, decreased LSD1 occupancy, and decreased Bdnf IV expression due to increased H3K9 dimethylation in AIE adult rats. Further, concomitant Lsd1 small interfering RNA (siRNA) infusion into the CeA prevents the miR-137-mediated reversal of AIE-induced adult anxiety and chromatin remodeling at the Bdnf IV promoter. These novel results highlight miR-137 as a potential therapeutic target for anxiety and AUD susceptibility after adolescent alcohol exposure in adulthood.
Collapse
|
53
|
Sakharkar AJ, Kyzar EJ, Gavin DP, Zhang H, Chen Y, Krishnan HR, Grayson DR, Pandey SC. Altered amygdala DNA methylation mechanisms after adolescent alcohol exposure contribute to adult anxiety and alcohol drinking. Neuropharmacology 2019; 157:107679. [PMID: 31229451 PMCID: PMC6681823 DOI: 10.1016/j.neuropharm.2019.107679] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 06/08/2019] [Accepted: 06/18/2019] [Indexed: 01/04/2023]
Abstract
Binge drinking during adolescence increases the risk for neuropsychiatric disorders including alcoholism in adulthood. DNA methylation in post-mitotic neurons is an important epigenetic modification that plays a crucial role in neurodevelopment. We examined the effects of intermittent ethanol exposure during adolescence on adult behavior and whether DNA methylation changes provide a plausible explanation for the lasting effects of this developmental insult. One hour after last adolescent intermittent ethanol (AIE), growth arrest and DNA damage inducible protein 45 (Gadd45a, Gadd45b, and Gadd45g) mRNA expression was increased and DNA methyltransferase (DNMT) activity and Dnmt3b expression was decreased in the amygdala as compared to adolescent intermittent saline (AIS) rats. However, AIE rats 24 h after last exposure displayed increased DNMT activity but normalized Gadd45 and Dnmt3b mRNA expression compared to AIS rats. In adulthood, rats exposed to AIE show increased Dnmt3b mRNA expression and DNMT activity, along with decreased Gadd45g mRNA expression in the amygdala. DNA methylation of neuropeptide Y (Npy) and brain-derived neurotrophic factor (Bdnf) exon IV is increased in the AIE adult amygdala compared to AIS adult rats. Treatment with the DNMT inhibitor 5-azacytidine (5-azaC) at adulthood normalizes the AIE-induced DNA hypermethylation of Npy and Bdnf exon IV with concomitant reversal of AIE-induced anxiety-like and alcohol-drinking behaviors. These results suggest that binge-like ethanol exposure during adolescence leads to dysregulation in DNA methylation mechanisms in the amygdala which may contribute to behavioral phenotypes of anxiety and alcohol use in adulthood.
Collapse
Affiliation(s)
- Amul J Sakharkar
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, 60612, USA; Jesse Brown Veterans Affairs Medical Center, Chicago, IL, 60612, USA
| | - Evan J Kyzar
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, 60612, USA; Jesse Brown Veterans Affairs Medical Center, Chicago, IL, 60612, USA
| | - David P Gavin
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, 60612, USA; Jesse Brown Veterans Affairs Medical Center, Chicago, IL, 60612, USA
| | - Huaibo Zhang
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, 60612, USA; Jesse Brown Veterans Affairs Medical Center, Chicago, IL, 60612, USA
| | - Ying Chen
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Harish R Krishnan
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, 60612, USA; Jesse Brown Veterans Affairs Medical Center, Chicago, IL, 60612, USA
| | - Dennis R Grayson
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, 60612, USA
| | - Subhash C Pandey
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, 60612, USA; Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, 60612, USA; Jesse Brown Veterans Affairs Medical Center, Chicago, IL, 60612, USA.
| |
Collapse
|
54
|
Waeiss RA, Knight CP, Carvajal GB, Bell RL, Engleman EA, McBride WJ, Hauser SR, Rodd ZA. Peri-adolescent alcohol consumption increases sensitivity and dopaminergic response to nicotine during adulthood in female alcohol-preferring (P) rats: Alterations to α7 nicotinic acetylcholine receptor expression. Behav Brain Res 2019; 376:112190. [PMID: 31473285 DOI: 10.1016/j.bbr.2019.112190] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 08/05/2019] [Accepted: 08/28/2019] [Indexed: 12/11/2022]
Abstract
Adolescent alcohol drinking has been linked to increased risk for drug abuse during adulthood. Nicotine microinjected directly into the posterior ventral tegmental area (pVTA) stimulates dopamine (DA) release in the nucleus accumbens (NAc) shell. The α7 nicotinic acetylcholine receptor (nAChR) is a potent regulator of dopaminergic activity in the pVTA. The current experiments examined the effects of peri-adolescent ethanol (EtOH) drinking on the ability of intra-pVTA nicotine to stimulate DA release during adulthood and alterations in α7 nAChR expression within the pVTA. Alcohol-preferring (P) female rats consumed EtOH and/or water during adolescence (post-natal day [PND] 30-60) or adulthood (PND 90-120). Thirty days following removal of EtOH, subjects received microinjections of 1 μM, 10 μM, or 50 μM nicotine into the pVTA concurrently with microdialysis for extracellular DA in the NAc shell. Brains were harvested from an additional cohort after PND 90 for quantification of α7 nAChR within the pVTA. The results indicated that only adolescent EtOH consumption produced a leftward and upward shift in the dose response curve for nicotine to stimulate DA release in the NAc shell. Investigation of α7 nAChR expression within the pVTA revealed a significant increase in animals that consumed EtOH during adolescence compared to naïve animals. The data suggests that peri-adolescent EtOH consumption produced cross-sensitization to the effects of nicotine during adulthood. The interaction between adolescent EtOH consumption and inflated adult risk for drug dependency could be predicated, at least in part, upon alterations in α7 nAChR expression within the mesolimbic reward pathway.
Collapse
Affiliation(s)
- Robert A Waeiss
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, United States.
| | - Christopher P Knight
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| | - Gustavo B Carvajal
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| | - Richard L Bell
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, United States; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| | - Eric A Engleman
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, United States; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| | - William J McBride
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, United States; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| | - Sheketha R Hauser
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| | - Zachary A Rodd
- Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN, 46202, United States; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
| |
Collapse
|
55
|
Crews FT, Robinson DL, Chandler LJ, Ehlers CL, Mulholland PJ, Pandey SC, Rodd ZA, Spear LP, Swartzwelder HS, Vetreno RP. Mechanisms of Persistent Neurobiological Changes Following Adolescent Alcohol Exposure: NADIA Consortium Findings. Alcohol Clin Exp Res 2019; 43:1806-1822. [PMID: 31335972 PMCID: PMC6758927 DOI: 10.1111/acer.14154] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 07/12/2019] [Indexed: 12/13/2022]
Abstract
The Neurobiology of Adolescent Drinking in Adulthood (NADIA) Consortium has focused on the impact of adolescent binge drinking on brain development, particularly on effects that persist into adulthood. Adolescent binge drinking is common, and while many factors contribute to human brain development and alcohol use during adolescence, animal models are critical for understanding the specific consequences of alcohol exposure during this developmental period and the underlying mechanisms. Using adolescent intermittent ethanol (AIE) exposure models, NADIA investigators identified long-lasting AIE-induced changes in adult behavior that are consistent with observations in humans, such as increased alcohol drinking, increased anxiety (particularly social anxiety), increased impulsivity, reduced behavioral flexibility, impaired memory, disrupted sleep, and altered responses to alcohol. These behavioral changes are associated with multiple molecular, cellular, and physiological alterations in the brain that persist long after AIE exposure. At the molecular level, AIE results in long-lasting changes in neuroimmune/trophic factor balance and epigenetic-microRNA (miRNA) signaling across glia and neurons. At the cellular level, AIE history is associated in adulthood with reduced expression of cholinergic, serotonergic, and dopaminergic neuron markers, attenuated cortical thickness, decreased neurogenesis, and altered dendritic spine and glial morphology. This constellation of molecular and cellular adaptations to AIE likely contributes to observed alterations in neurophysiology, measured by synaptic physiology, EEG patterns, and functional connectivity. Many of these AIE-induced brain changes replicate findings seen in postmortem brains of humans with alcohol use disorder (AUD). NADIA researchers are now elucidating mechanisms of these adaptations. Emerging data demonstrate that exercise, antiinflammatory drugs, anticholinesterases, histone deacetylase inhibitors, and other pharmacological compounds are able to prevent (administered during AIE) and/or reverse (given after AIE) AIE-induced pathology in adulthood. These studies support hypotheses that adolescent binge drinking increases risk of adult hazardous drinking and influences brain development, and may provide insight into novel therapeutic targets for AIE-induced neuropathology and AUDs.
Collapse
Affiliation(s)
- Fulton T Crews
- Bowles Center for Alcohol Studies, School of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - Donita L Robinson
- Bowles Center for Alcohol Studies, School of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - L Judson Chandler
- Department of Neuroscience, Charleston Alcohol Research Center, Charleston, South Carolina
| | - Cindy L Ehlers
- Department of Neurosciences, The Scripps Research Institute, La Jolla, California
| | - Patrick J Mulholland
- Department of Neuroscience, Charleston Alcohol Research Center, Charleston, South Carolina
| | - Subhash C Pandey
- Center for Alcohol Research in Epigenetics, Department of Psychiatry, University of Illinois at Chicago and Jesse Brown VA Medical Center, Chicago, Illinois
| | - Zachary A Rodd
- Department of Psychiatry and Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, Indiana
| | - Linda P Spear
- Developmental Exposure Alcohol Research Center, Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, New York
| | - H Scott Swartzwelder
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, North Carolina
| | - Ryan P Vetreno
- Bowles Center for Alcohol Studies, School of Medicine, University of North Carolina, Chapel Hill, North Carolina
| |
Collapse
|
56
|
Wolstenholme JT, Miles MF. Connecting the Dots: Adolescent Alcohol, Enhancer RNA, and Anxiety. Biol Psychiatry 2019; 85:884-885. [PMID: 31122337 DOI: 10.1016/j.biopsych.2019.04.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 04/03/2019] [Indexed: 12/22/2022]
Affiliation(s)
- Jennifer T Wolstenholme
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia; Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia
| | - Michael F Miles
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia; Department of Neurology, Virginia Commonwealth University, Richmond, Virginia; Virginia Commonwealth University Alcohol Research Center, Virginia Commonwealth University, Richmond, Virginia.
| |
Collapse
|