Withdrawal from chronic alcohol exposure leads to tissue-specific recovery of the zebrafish transcriptome
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ABSTRACT: Alcohol consumption can lead to a wide-range of systemic disorders brought about by transcriptional changes. Recent studies have shown altered behavioral and expression changes in zebrafish on exposure to alcohol. We have identified changes associated with transcriptome profiles in response to chronic alcohol exposure and extent of recovery upon withdrawal. Our results indicate a tissue-specific response where the brain responds positively to withdrawal when compared to liver. We identified two distinct classes of genes in response to withdrawal from alcohol exposure – one group recovered the pre-exposure expression profile while the other set of genes retained altered expression profiles despite withdrawing from alcohol whose altered expression profiles remained changed even after withdrawal. We also examined gender-specific responses to alcohol. Male fish appear to be more susceptible to changes induced by alcohol indicated by a higher percent of genes appearing to change their expression profiles when compared to females. Female fish appear to show a better recovery as compared to males as a sizable number of genes appear to have their expression levels recovered upon the introduction of withdrawal. Overall, our work identifies pathways / genes perturbed by exposure to alcohol and demonstrates the extent of tissue-specific transcriptional changes and takes into account the variability of gender in assessing the effect of chronic alcoholism and withdrawal.
Project description:While women are more vulnerable than men to many of the medical consequences of alcohol abuse, the role of sex in the response to ethanol is controversial. Neuroadaptive responses that result in the hyperexcitability associated with withdrawal from chronic ethanol likely reflect gene expression changes. We have examined both genders for the effects of withdrawal on brain gene expression using mice with divergent withdrawal severity that have been selectively bred from a genetically heterogeneous population. A total of 295 genes were identified as ethanol regulated from each gender of each selected line by microarray analyses. Hierarchical cluster analysis of the arrays revealed that the transcriptional response correlated with sex rather than with the selected withdrawal phenotype. Consistent with this, gene ontology category over-representation analysis identified cell death and DNA/RNA binding as targeted classes of genes in females, while in males, protein degradation, and calcium ion binding pathways weremore altered by alcohol. Examination of ethanol regulated genes and these distinct signaling pathways suggested enhanced neurotoxicity in females. Histopathological analysis of brain damage following ethanol withdrawal confirmed elevated cell death in female but not male mice. The sexually dimorphic response was observed irrespective of withdrawal phenotype. Combined, these results indicate a fundamentally distinct neuroadaptive response in females compared to males during chronic ethanol withdrawal and are consistent with observations that female alcoholics may be more vulnerable than males to ethanol-induced brain damage associated with alcohol abuse.
Project description:While women are more vulnerable than men to many of the medical consequences of alcohol abuse, the role of sex in the response to ethanol is controversial. Neuroadaptive responses that result in the hyperexcitability associated with withdrawal from chronic ethanol likely reflect gene expression changes. We have examined both genders for the effects of withdrawal on brain gene expression using mice with divergent withdrawal severity that have been selectively bred from a genetically heterogeneous population. A total of 295 genes were identified as ethanol regulated from each gender of each selected line by microarray analyses. Hierarchical cluster analysis of the arrays revealed that the transcriptional response correlated with sex rather than with the selected withdrawal phenotype. Consistent with this, gene ontology category over-representation analysis identified cell death and DNA/RNA binding as targeted classes of genes in females, while in males, protein degradation, and calcium ion binding pathways weremore altered by alcohol. Examination of ethanol regulated genes and these distinct signaling pathways suggested enhanced neurotoxicity in females. Histopathological analysis of brain damage following ethanol withdrawal confirmed elevated cell death in female but not male mice. The sexually dimorphic response was observed irrespective of withdrawal phenotype. Combined, these results indicate a fundamentally distinct neuroadaptive response in females compared to males during chronic ethanol withdrawal and are consistent with observations that female alcoholics may be more vulnerable than males to ethanol-induced brain damage associated with alcohol abuse. A total of 32 microarrays were run with 4 biological replicates per treatment, line, and sex. Selection replicates (i.e. WSP-1 and WSP-2) for each treatment, line, and sex were collapsed to improve statistical power (n=4) and to facilitate in the identification of phenotype related effects and exclude selection artifacts. For comparisons, EtOH regulation was determined by comparing 4 arrays from (for example) Male WSR EtOH treated versus 4 arrays from Male WSR Air treated arrays.
Project description:Ethanol is the most common substance of abuse in the US, and abuse can lead to physical dependence, addiction, brain damage and premature death. The cycle of alcohol addiction has been described as a composite consisting of three stages: intoxication, withdrawal and craving/abstinence. As a complex brain disorder, there is evidence for both a genetic contribution to risk and sexually-dimorphic responses in alcoholism, but an overall understanding of the biological contributions and the neuroadaptive underpinnings of alcohol addiction is limited. Utilizing novel genetic animal models with highly divergent withdrawal severity, Withdrawal Seizure-Resistant (WSR) and Withdrawal Seizure-Prone (WSP) selected lines of mice and by examining both sexes, the distinct or common contributions of response to alcohol genotype/phenotype and of sex to addiction stages over time were characterized. Transcriptional profiling was performed to identify neuroadaptive changes as a consequence of chronic intoxication in the medial prefrontal cortex (mPFC). Significant expression differences were identified for each line and tracked over a behaviorally-relevant time course that covered each stage of alcohol addiction; i.e., after chronic intoxication, during peak withdrawal, and after a defined period of abstinence. Females were more responsive to ethanol with higher fold expression differences. Data structure was analyzed by bioinformatics, which showed a strong effect of sex with high similarity of male vs. female expression profiles during chronic intoxication and at peak withdrawal irrespective of genetic background. However, during abstinence, striking differences were observed instead between the lines/phenotypes irrespective of sex. Because sex was the strongest influence on neuroadaptive changes overall, confirmation analysis compared males vs. females. Notably, results revealed distinct inflammatory signaling between males and females at peak withdrawal, with a pro-inflammatory inflammotoxic phenotype in females but in contrast overall suppression of immune signaling in males. Thus, the early response to chronic intoxication is strongly influenced by sex while pathways that are altered during a period of abstinence are dependent on genotype. Combined, these results suggest that each stage of the addiction cycle is influenced differentially by sex vs. genetic background and support the development of distinct translational targets for stage- and sex-specific therapies for the treatment of alcohol withdrawal and the maintenance of sobriety.
Project description:Rats were trained to orally self-administer alcohol in a concurrent, two-lever, free-choice contingency using a modification of the sweet solution fading procedure (O'Dell et al., 2004; Roberts et al., 2000; Vendruscolo et al., 2012). Following acquisition of self-administration, rats were allowed to self-administer unsweetened alcohol (10%) for 4 weeks and were then assigned to two groups matched by levels of responding: one group (dependent group) was exposed to chronic, intermittent ethanol vapors for 4 weeks to induce dependence; the other group (nondependent group) was not exposed to ethanol vapor. After a month of vapor exposure, rats were again tested during acute withdrawal (6-8 hours after removal from the vapor chambers) until stable levels of alcohol intake were achieved. As expected, alcohol vapor-exposed rats self-administered significantly greater amounts of alcohol than control rats not exposed to alcohol vapor during acute withdrawal. Rats were sacrificed during protracted abstinence (3 weeks after the end of alcohol vapor exposure) along with age-matched alcohol naive rats.
Project description:The objective of The Center for Alcohol Research in Epigenetics (CARE) is to identify gene regulatory pathways in hippocampus that are altered in response to chronic ethanol administration and withdrawal.
Project description:Rats were trained to orally self-administer alcohol in a concurrent, two-lever, free-choice contingency using a modification of the sweet solution fading procedure (O'Dell et al., 2004; Roberts et al., 2000; Vendruscolo et al., 2012). Following acquisition of self-administration, rats were allowed to self-administer unsweetened alcohol (10%) for 4 weeks and were then assigned to two groups matched by levels of responding: one group (dependent group) was exposed to chronic, intermittent ethanol vapors for 4 weeks to induce dependence; the other group (nondependent group) was not exposed to ethanol vapor. After a month of vapor exposure, rats were again tested during acute withdrawal (6-8 hours after removal from the vapor chambers) until stable levels of alcohol intake were achieved. As expected, alcohol vapor-exposed rats self-administered significantly greater amounts of alcohol than control rats not exposed to alcohol vapor during acute withdrawal. Rats were sacrificed during protracted abstinence (3 weeks after the end of alcohol vapor exposure) along with age-matched alcohol naive rats. 96 gene expression profiles (GEP) were obtained from 8 brain regions believed to be relevant in alcoholM-bM-^@M-^Ys reinforcing properties using the Affymetrix RN230.2 platform. Specifically, the following brain regions were microdissected and analyzed from nondependent and dependent alcohol self-administering rats as well as age-matched alcohol naive rats: (a) medial prefrontal cortex (MPF), (b) shell and (c) core NAc sub-regions, (d) central nucleus (CeA) and (e) basolateral nucleus of the amygdala (BLA), (f) dorsolateral and (g) ventral bed nucleus of the stria terminalis (BNST), and (h) ventral tegmental area (VTA).
Project description:The early exposure to the artificial odorant phenyl ethyl alcohol (PEA) is correlated with odor memory formation and the changes in gene expression in olfactory epithelium of zebrafish. In this study we performed a transcriptomic analysis using RNA seq, in order to compare the gene expression in the olfactory epithelium of adult zebrafish between PEA exposed fish during the early development and non-exposed fish
Project description:The objective of The Center for Alcohol Research in Epigenetics (CARE) is to identify gene regulatory pathways in ventral tegmental area (VTA) that are altered in response to chronic ethanol administration and withdrawal.
Project description:Ethanol is the most common substance of abuse in the US, and abuse can lead to physical dependence, addiction, brain damage and premature death. The cycle of alcohol addiction has been described as a composite consisting of three stages: intoxication, withdrawal and craving/abstinence. As a complex brain disorder, there is evidence for both a genetic contribution to risk and sexually-dimorphic responses in alcoholism, but an overall understanding of the biological contributions and the neuroadaptive underpinnings of alcohol addiction is limited. Utilizing novel genetic animal models with highly divergent withdrawal severity, Withdrawal Seizure-Resistant (WSR) and Withdrawal Seizure-Prone (WSP) selected lines of mice and by examining both sexes, the distinct or common contributions of response to alcohol genotype/phenotype and of sex to addiction stages over time were characterized. Transcriptional profiling was performed to identify neuroadaptive changes as a consequence of chronic intoxication in the medial prefrontal cortex (mPFC). Significant expression differences were identified for each line and tracked over a behaviorally-relevant time course that covered each stage of alcohol addiction; i.e., after chronic intoxication, during peak withdrawal, and after a defined period of abstinence. Females were more responsive to ethanol with higher fold expression differences. Data structure was analyzed by bioinformatics, which showed a strong effect of sex with high similarity of male vs. female expression profiles during chronic intoxication and at peak withdrawal irrespective of genetic background. However, during abstinence, striking differences were observed instead between the lines/phenotypes irrespective of sex. Because sex was the strongest influence on neuroadaptive changes overall, confirmation analysis compared males vs. females. Notably, results revealed distinct inflammatory signaling between males and females at peak withdrawal, with a pro-inflammatory inflammotoxic phenotype in females but in contrast overall suppression of immune signaling in males. Thus, the early response to chronic intoxication is strongly influenced by sex while pathways that are altered during a period of abstinence are dependent on genotype. Combined, these results suggest that each stage of the addiction cycle is influenced differentially by sex vs. genetic background and support the development of distinct translational targets for stage- and sex-specific therapies for the treatment of alcohol withdrawal and the maintenance of sobriety. A total of 32 microarrays were run with 4 biological replicates per treatment, line, and sex. Selection replicates (i.e. WSP-1 and WSP-2) for each treatment, line, and sex were collapsed to improve statistical power (n=4) and to facilitate in the identification of phenotype related effects and exclude selection artifacts. For comparisons, EtOH regulation was determined by comparing 4 arrays from (for example) Male WSR EtOH treated versus 4 arrays from Male WSR Air treated arrays.
Project description:Alcohol use disorder (AUD) is a chronic mental illness in which patients often achieve protracted periods of abstinence prior to relapse. Epigenetic mechanisms may provide an explanation for the persisting gene expression changes that can be observed even after long periods of abstinence and may contribute to relapse. In this study we examined two stable histone modifications, histone 3 lysine 4 tri-methylation (H3K4me3) and histone 3 lysine 27 tri-methylation (H3K27me3), in the prefrontal cortex of Withdrawal Seizure Resistant (WSR) mice 21 days after 72 hours of ethanol vapor exposure. These histone modifications were selected because they are associated with active promoters (H3K4me3) and repressed gene expression in a euchromatic environment (H3K27me3). We performed a genome-wide analysis to identify differences in H3K4me3 and H3K27me3 levels in post-ethanol exposure vs. control mice by ChIP-seq. We detected a global reduction in H3K4me3 peaks and increase in H3K27me3 peaks in post-ethanol exposure mice compared to controls, these changes are consistent with persistent reductions in gene expression and suggest differential epigenetic regulation of genes during this post-exposure period. We also examined the correspondence between genes that displayed changes in H3K4me3 and/or H3K27me3 and were differentially expressed. The expression of 52% of the genes with altered H3K4me3 binding and 40% of genes with H3K27me3 differences found here is altered by ethanol exposure based on analysis of prior studies. Finally, pathway analysis of genes displaying changes in H3K4me3 and H3K27me3 revealed enrichment for genes involved in proteoglycan and calcium signaling pathways, respectively. The chromatin changes associated with the 21-day post-exposure period suggest that this period is a unique state in the addiction cycle that differs from ethanol intoxication and acute withdrawal. These results provide insights into the enduring effects of ethanol on proteoglycan and calcium signaling genes in the brain.