Wilson disease (WD) is an inherited, autosomal recessive, copper (Cu) accumulation disorder, which is caused by the dysfunction of a Cu-transporting P-type ATPase that is crucial in the hepatocellular utilization and biliary excretion f Cu. WD is characterized by a remarkable heterogeneity in its clinical hepatic presentation. The failure to identify specific genotype-to-phenotype correlations could be due in part to the presence of epigenetic factors affecting phenotype expression. The HYPOTHESIS of the proposed research is that the gestational supply of dietary methyl groups modifies fetal DNA methylation mechanisms that regulate the expression of genes involved in liver damage in WD and persist through subsequent life of the offspring. We will test this hypothesis in the tx-j mouse model of WD, which we have previously characterized as showing global DNA hypomethylation and changes in the expression of genes related to hepatic methionine metabolism.
Our SPECIFIC AIMS will be to test if 1) Specific Aim 1: maternal methyl status during pregnancy will affect transcriptome and methylome status in fetal liver;2) Specific Aim 2: maternal methyl status during pregnancy will affect parameters of methionine metabolism and persisting changes in on hepatic global DNA methylation and gene expression in 4 month old offspring. The study will be conducted on livers of fetuses from tx-j and wild-type dams fed a choline-supplemented or control diets before mating and during gestation (Specific Aim 1), and on livers from offspring of tx-j and wild-type dams. The proposed experiments will use epigenetic techniques of dot-blot for global DNA methylation, RNA-sequencing analysis, and MethylC-seq analysis to determine the gene specific methylation status of CpG sites genome-wide. The anticipated findings are that aberrant fetal methionine metabolism and altered global and gene-specific DNA methylation will persist in offspring and be prevented by maternal dietary provision of choline. These findings will provide important evidence that WD is a condition characterized not only by Cu accumulation but also by global DNA hypomethylation which can be corrected by provision of methyl groups in the maternal diet. Positive results from this study will provide a rationale for the potential use of agents that modify gene methylation status in the prevention and/or treatment of clinical manifestations of WD. The present proposal is a novel departure based on current K08 progress and will form the basis for a subsequent R01 application to study methylation status over the lifespan of animal models and humans with WD by exploring the addition of dietary methyl donors such as choline to the traditional anti-Cu treatment in order to modify the disease course in difficult and less responsive cases and as adjuvant to traditional anti-Cu agents.
Epigenetic and environmental factors may contribute to the phenotypic presentation of Wilson disease. We will study the effects of gestational supply of dietary methyl groups on fetal and offspring DNA methylation mechanisms that regulate the expression of genes involved in liver damage in an animal model of Wilson Disease. The study will provide insights into the role of methyl donors to modify the disease course in difficult and less responsive cases.
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| Medici, Valentina; Kieffer, Dorothy A; Shibata, Noreene M et al. (2016) Wilson Disease: Epigenetic effects of choline supplementation on phenotype and clinical course in a mouse model. Epigenetics 11:804-818 |
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