Project description:Despite recent extensive genomic and genetic studies on behavioral responses to ethanol, relatively few new therapeutic targets for the treatment of alcohol use disorder have been validated. Here we describe a cross-species genomic approach focused on identifying gene networks associated with chronic ethanol consumption. To identify brain mechanisms underlying a chronic ethanol consumption phenotype highly relevant to human alcohol use disorder, and to elucidate potential future therapeutic targets, we conducted a genomic study in a nonhuman primate model of chronic open-access ethanol consumption. Microarray analysis of RNA expression in anterior cingulate and subgenual cortices from rhesus macaques was performed across multiple cohorts of animals. Gene networks correlating with ethanol consumption or showing enrichment for ethanol-regulated genes were identified, as were major ethanol-related hub genes within these networks. A subsequent consensus module analysis was used to co-analyze monkey data with expression data from a chronic intermittent ethanol vapor-exposure and consumption model in C57BL/6J mice. Ethanol-related gene networks conserved between primates and rodents were enriched for genes involved discrete biological functions, including; myelination, synaptic transmission, chromatin modification, Golgi apparatus function, translation, cellular respiration, and RNA processing. The myelin-related network, in particular, showed strong correlations with ethanol consumption behavior and displayed marked network reorganization between control and ethanol-drinking animals. Further bioinformatics analysis revealed that these networks also showed highly significant overlap with other ethanol-regulated gene sets. Altogether, these studies provide robust primate and rodent cross-species validation of gene networks associated with chronic ethanol consumption. Our results also suggest potential novel focal points for future therapeutic interventions in alcohol use disorder.

Project description:Chronic and binge ethanol consumption in humans and in animal models has been associated with the induction of injury (such as fibrosis and scarring) in the liver as well as the intestine, brain, lung and immune system. The effects of chronic ethanol consumption on the human kidney are protective as seen in large population studies are controversial with the preponderance of the data suggesting protection less so than injury. The most recent meta-analysis was by Konig et al (2015) who studied 5476 participants aged 28–75 years from the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study to assess associations between alcohol consumption and risk of chronic kidney disease (CKD). They found in this population-based cohort, alcohol consumption was inversely associated with the risk of developing CKD. The protective effects of ethanol on the kidney present a unique model system to develop new hypothesis on protection against end organ damage by fibrosis. The data on the effects of alcohol or alcohol consumption at the molecular level on renal parenchyma are sparse. In cell culture and animal models chronic ethanol exposure has been show to induce protein post-translational modification (acetylation), protein expression (upregulation of cytochrome P450 CYP2E1 and local platelet-activating factor receptor (PAFR) ligand formation) as well as neutrophil infiltration and activation. Since hepatocytes do not express PAFR, these data suggest that the response of the kidney to chronic alcohol consumption is distinct from that of the liver or lung. Therefore, we hypothesized that mechanisms of ethanol-induced renal injury or protection are regulated by a protein signaling networks (PSN) modulated acutely by the phosphoproteome and long term epigenetically by the acetylproteome. To address this hypothesis we have initiated a tiered proteomics study to determine the effects of chronic alcohol consumption on the murine kidney and with a secondary insult of acute exposure of lipopolysaccharide (LPS) on the renal proteome, phosphoproteome and the acetylproteome. Data have already been collected on the total proteome and the phosphoproteome using a multiplexing approach. Data will be collected early spring on the acetylproteome.

Project description:Introduction: Though heavy alcohol drinking has been well characterized as causing a variety of injuries, recent epidemiological evidence in humans suggests moderate consumption may provide beneficial effects. For example, there exists a J- or U-shaped relationship between the level of alcohol intake and cardiovascular disease risk. We investigated the underlying mechanisms of these positive consequences by identifying which genes are responsive to moderate alcohol intake in the liver, the primary site for alcohol metabolism. Methods: Twelve female, inbred, alcohol-preferring (iP10a) rats were split equally between chronic water exposure and voluntary chronic ethanol exposure. Hepatic cholesterol and triglyceride levels were analyzed both histologically and biochemically. Hepatic transcriptomes were paired-end sequenced on the Illumina HiScanSQ system. Reads were analyzed and mapped using CLCbio Genomics Workbench 4.9. We confirmed altered expression of a subset of genes using TaqMan-based qRT-PCR. To quantify DNA methylation, we first digested DNA with methylation sensitive restriction enzymes and then performed qPCR using TaqMan assays surrounding the digest sites. Calculating M-NM-^TCt between a mock digest and digest determines the percent methylation in that locus. Results: Voluntary alcohol consumption in iP10a rats modeled moderate consumption in humans. These levels did not result in intrahepatic fat accumulation. Sequencing produced ~1.2 Gb of sequence per sample, and 65% of reads mapped uniquely. Using a FDR corrected p value of 0.05 we found 250 altered transcripts. Ontology analysis of genes with a fold change M-bM-^IM-%1.3 identified many cholesterol synthesis genes and cytoskeleton subunit genes, all of which were down-regulated. Of the 28 genes reanalyzed by qRT-PCR, altered expression was confirmed in 24 genes including the majority of the cholesterol synthesis and cytoskeleton subunit genes. Lastly, we profiled methylation throughout the promoter and gene body of four genes elicited in the RNA-Seq experiment. We found that alcohol caused demethylation at all loci; however this loss happened in a site-specific, tightly regulated manner. Conclusion: Voluntary consumption in the iP10a animals models moderate consumption in humans, does not produce intrahepatic fat accumulation, and causes down-regulation of a majority of cholesterol synthesis genes. Moderate alcohol also results in a tightly-regulated demethylation effect. Our results explain, at least in part, the J- or U-shaped relationship between level of alcohol intake and cardiovascular disease risk. We sequenced 12 female iP10a rat hepatic transcriptomes providing 6 biological replicates for water control and 6 for ethanol treatment.

Dataset Information

E-GEOD-13524

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