The liver X-receptor gene promoter is hypermethylated in a mouse model of prenatal protein restriction

Abstract

van Straten EME, Bloks VW, Huijkman NCA, Baller JFW, van Meer H, Lü tjohann D, Kuipers F, Plö sch T. The liver X-receptor gene promoter is hypermethylated in a mouse model of prenatal protein restriction. Am J Physiol Regul Integr Comp Physiol 298: R275-R282, 2010. First published November 4, 2009 doi:10.1152/ajpregu.00413.2009.-Prenatal nutrition as influenced by the nutritional status of the mother has been identified as a determinant of adult disease. Feeding low-protein diets during pregnancy in rodents is a well-established model to induce programming events in offspring. We hypothesized that protein restriction would influence fetal lipid metabolism by inducing epigenetic adaptations. Pregnant C57BL/6J mice were exposed to a protein-restriction protocol (9% vs. 18% casein). Shortly before birth, dams and fetuses were killed. To identify putative epigenetic changes, CG-dinucleotiderich region in the promoter of a gene (CpG island) methylation microarrays were performed on DNA isolated from fetal livers. Two hundred four gene promoter regions were differentially methylated upon protein restriction. The liver X-receptor (Lxr) alpha promoter was hypermethylated in protein-restricted pups. Lxr alpha is a nuclear receptor critically involved in control of cholesterol and fatty acid metabolism. The mRNA level of Lxra was reduced by 32% in fetal liver upon maternal protein restriction, whereas expression of the Lxr target genes Abcg5/Abcg8 was reduced by 56% and 51%, respectively, measured by real-time quantitative PCR. The same effect, although less pronounced, was observed in the fetal intestine. In vitro methylation of a mouse Lxra-promoter/luciferase expression cassette resulted in a 24-fold transcriptional repression. Our study demonstrates that, in mice, protein restriction during pregnancy interferes with DNA methylation in fetal liver. Lxra is a target of differential methylation, and Lxra transcription is dependent on DNA methylation. It is tempting to speculate that perinatal nutrition may influence adult lipid metabolism by DNA methylation, which may contribute to the epidemiological relation between perinatal/neonatal nutrition and adult disease.programming; epigenetics; CpG island methylation microarray AN OVERWHELMING BODY OF EVIDENCE links fetal (mal)nutrition to the development of chronic diseases at adult age [developmental origins of health and disease hypothesis (4, 5)]. Epidemiological data show that children small for gestational age, who were undernourished during intrauterine development, have a higher risk of developing cardiovascular diseases or the metabolic syndrome in adulthood (3). In humans, fetal malnutrition is related to external factors (starvation, malnutrition, drug consumption of the mother) or to internal factors, such as placental dysfunction leading to reduced routing of nutrients to the fetus (32).Knowledge of underlying mechanisms of metabolic programming may help to design strategies to halt the current epidemic in metabolic diseases. For this purpose, several animal mo...

Maternal protein restriction leads to enhanced hepatic gluconeogenic gene expression in adult male rat offspring due to impaired expression of the liver X receptor

“…Previous studies strongly suggest the role of epigenetics in mediating the effects of fetal programming longterm into adulthood (Rees et al 2000, Lillycrop et al 2005, Burdge et al 2007, Park et al 2008, van Straten et al 2010. By 4 months of age, we demonstrated that LP males exhibited significantly decreased acetylation of histone H3 (K9,14) associated with trends of decreased RNA polymerase II recruitment and decreased methylation of histone H3 (K4) surrounding the promoter of Lxra.…”

“…Forward (5 0 -GGCTTCACTGGTTGATCCAT-3 0 ) and reverse (5 0 -AGGGGGTTGATTCTTGAGGT-3 0 ) primers were designed to amplify the K135 to C144 bp region surrounding the C1 bp TSS of Lxra. Recent evidence indicates that there is epigenetic regulation in the CG-rich regions of the Lxra promoter around the TSS in another rodent model of MPR (van Straten et al 2010). Thus, primers around the promoter were used to examine the binding of RNA polymerase II, acetylation of histone H3 (K9,14), methylation of histone H3 (K4) and trimethylation of histone H3 (K9) at the TSS of Lxra.…”

“…This was found to be due, in part, to repressive changes in histone modifications at the LXRE site of the Cyp7a1 promoter. Other studies in mice have demonstrated that MPR leads to hypermethylation of the Lxra (Nr1h3) promoter in association with decreased Lxra mRNA in the liver tissue of embryonic day 19.5 fetuses, however the effect on posttranslational histone modifications surrounding Lxra remains elusive (van Straten et al 2010). While others and we have demonstrated that MPR can lead to long-term epigenetic alterations of LXR-target genes involved in cholesterol and lipid homeostasis, it is not known if LXR-target genes impairing hepatic gluconeogenesis are altered.…”

Epigenetic regulation in obesity

“…74 Similarly, a liver X receptor involved in cholesterol and fatty acid metabolism was hypomethylated in rodent offspring from maternal protein restriction. 75 Folate supplementation has been used to restore methylation back to wild-type levels because folate is a methyl donor and has been linked to DNA methylation in a dose-dependent manner, as reviewed by Kim. 76 The hypomethylation of Ppar-a after in utero exposure to protein restriction was rescued by folate supplementation to the postweaning young offspring.…”

Epigenetics: Understanding How our Choices Lead to our Diseases

“…Epigenetic changes occur most often during gestation, neonatal development, puberty, and old age [9]. However, animal studies and human epidemiologic data suggest that long-term epigenetic changes that manifest in disease phenotypes are especially critical during the prenatal and neonatal stages as well as during times of 'dietary transition' in adulthood [32][33][34][35].…”