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: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:BackgroundThe prefrontal cortex (PFC) acts as an integrative hub for the processing of cortical and subcortical input into meaningful efferent signaling, permitting complex associative behaviors. PFC dysfunction is consistently observed with ethanol (EtOH) dependence and is a core component of the pathology of alcohol use disorders in current models of addiction. While intracortical gamma-aminobutryric acid (GABA)ergic neurotransmission is understood to be essential for maintaining coordinated network activity within the cortex, relatively little is known regarding functional GABAergic adaptations in PFC during EtOH dependence.MethodsIn the present study, male and female (> postnatal day 60) Sprague-Dawley rats were administered EtOH (5.0 g/kg; intragastric gavage) for 14 to 15 consecutive days. Twenty-four hours after the final administration, animals were sacrificed and brains extracted for electrophysiological recordings of isolated GABAA receptor-mediated currents or analysis of GABAA receptor subunit protein expression in deep-layer PFC neurons.ResultsChronic EtOH exposure significantly attenuated activity-dependent spontaneous GABAA receptor-mediated inhibitory postsynaptic current (IPSC) frequency with no effect on amplitude. Furthermore, analysis of IPSC decay kinetics revealed a significant enhancement of IPSC decay time that was associated with decrements in expression of the α1 GABAA receptor subunit, indicative of further impaired phasic inhibition. These phenomena occurred irrespective of neuron projection destination and sex. Based on previous observations by our laboratory of an epigenetic mechanism for EtOH-induced changes in cortical GABAA receptor subunit expression, the histone deacetylase inhibitor Trichostatin A was administered to water- and EtOH-exposed animals, and prevented EtOH-induced changes in spontaneous IPSC frequency, IPSC decay kinetics, and GABAA receptor subunit expression.ConclusionsTaken together, these results demonstrate that chronic EtOH exposure impairs synaptic inhibitory neurotransmission in deep-layer pyramidal neurons of the medial PFC in both male and female rats. These maladaptations occur in neurons projecting to numerous regions implicated in the sequelae of EtOH dependence, offering a mechanistic link between the manifestation of PFC dysfunction and negative affective states observed with extended consumption.

Dataset Information

Prefrontal cortex expression of chromatin modifier genes in male WSP and WSR mice changes across ethanol dependence, withdrawal, and abstinence.

Publications

Prefrontal cortex expression of chromatin modifier genes in male WSP and WSR mice changes across ethanol dependence, withdrawal, and abstinence.

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