Coordinated dysregulation of mRNAs and microRNAs in the rat medial prefrontal cortex following a history of alcohol dependence

Abstract

Long-term changes in brain gene expression have been identified in alcohol dependence, but underlying mechanisms remain unknown. Here, we examined the potential role of microRNAs for persistent gene expression changes in the rat medial prefrontal cortex after a history of alcohol dependence. Two-bottle free-choice alcohol consumption increased following 7-week exposure to intermittent alcohol intoxication. A bioinformatic approach using microarray analysis, qPCR, bioinformatic analysis, and microRNA-mRNA integrative analysis identified expression patterns indicative of a disruption in synaptic processes and neuroplasticity. 41 rat-microRNAs and 165 mRNAs in the medial prefrontal cortex were significantly altered after chronic alcohol exposure. A subset of the microRNAs and mRNAs was confirmed by qPCR. Gene ontology categories of differential expression pointed to functional processes commonly associated with neurotransmission, neuroadaptation, and synaptic plasticity. microRNA-mRNA expression pairing identified 33 microRNAs putatively targeting 89 mRNAs suggesting transcriptional networks involved in axonal guidance and neurotransmitter signaling. Our results demonstrate a significant shift in microRNA expression patterns in the medial prefrontal cortex following a history of dependence. Due to their global regulation of multiple downstream target transcripts, microRNAs may play a pivotal role in the reorganization of synaptic connections and long term neuroadaptations in alcohol dependence. microRNA-mediated alterations of transcriptional networks may be involved in disrupted prefrontal control over alcohol-drinking observed in alcoholic patients.

Synaptic microRNAs Coordinately Regulate Synaptic mRNAs: Perturbation by Chronic Alcohol Consumption

“…We used a combination of unbiased methods to reveal key microRNAs and their targets. Chronic alcohol consumption caused robust changes in synaptic microRNA expression levels consistent with those seen in human alcoholics (Lewohl et al, 2011) and in other animal models of dependence Alcohol-responsive synaptic microRNAs and mRNAs D Most et al Nunez et al, 2013;Tapocik et al, 2013). We further identified microRNAs with overlapping patterns of expression that correlated with alcohol consumption.…”

“…For cell types and immune response enrichment, we used the following lists of genes: neurons, astrocytes and oligodendrocytes (Cahoy et al, 2008), microglia (cured from Oldham et al, 2008), and glutamate/GABA (Sugino et al, 2006). For cross species comparison, we used lists from alcohol vapor-treated rats (Tapocik et al, 2013) and human alcoholics (Lewohl et al, 2011) to identify conserved alcoholresponsive microRNAs. Drugs that potentially target the alcohol-responsive mRNAs and the 'mRNA targets of the alcohol-responsive microRNAs' were found using Ingenuity Pathway Analysis (IPA, Ingenuity Systems, Qiagen, CA).…”

“…Exposure to alcohol and other drugs of abuse modulates microRNA expression in the brain (Pietrzykowski et al, 2008;He et al, 2010;Eipper-Mains et al, 2011;Lewohl et al, 2011;Tapocik et al, 2013). MicroRNAs have important roles in learning and memory (Konopka et al, 2010), and are also altered in addiction-related behaviors, such as cocaineconditioned place preference (Chandrasekar and Dreyer, 2011), cocaine-seeking behavior , and selfadministration of alcohol (Tapocik et al, 2014).…”

“…Little is known about the microRNAs involved in the regulation of synaptic mRNA translation during alcohol dependence. Studies investigating the effects of chronic alcohol consumption in standard tissue (total homogenate, TH) preparations found a persistent change in the expression of microRNAs and their target mRNAs in humans, mice, and rats (Lewohl et al, 2011;Gorini et al, 2013;Nunez et al, 2013;Tapocik et al, 2013). However, the standard TH preparation likely underestimates the number and magnitude of alcoholresponsive transcripts localized in the synapse (Lewohl et al, 2011;Most et al, 2014).…”

Proteomic Approaches and Identification of Novel Therapeutic Targets for Alcoholism

“…The application of comprehensive, integrative approaches will define the future of alcohol research (Rodd et al, 2007;Tabakoff et al, 2009;Tapocik et al, 2013) and promises to be fruitful in elucidating the mechanisms underlying alcohol addiction. Genetic and biological studies in animal models or post-mortem human brain, with epidemiological and clinical surveys on human subjects, should be integrated with genomic data.…”