Maternal methyl-donor supplementation and hypothalamic methylation stability

Background: Maternal nutrition can shape fetal epigenetic programming with long-term health effects. This study tested whether central and peripheral tissues differ in responsiveness to maternal methyl-donor supplementation. Methods: C57BL/6 dams received either standard chow (control) or a methyl-donor-enriched diet during pregnancy. Offspring were allocated to three groups: (1) control (mother and offspring on standard chow), (2) prenatal exposure (mother on methyl-donor diet during pregnancy, offspring on standard chow thereafter), and (3) combined exposure (mother on methyl-donor diet during pregnancy and lactation, offspring continued methyl-donor diet postnatally). Global DNA methylation was measured by ELISA in brain and hypothalamus (n = 10) and in liver, spleen, and heart (n = 5). Exploratory hypothalamic gene expression analysis compared group 2 vs. controls (n = 4). Results: Prenatal supplementation was associated with increased global 5-methylcytosine levels in brain and hypothalamus (both p < 0.01). In the hypothalamus, this elevation persisted irrespective of later diet, whereas peripheral organs displayed ongoing plasticity and responded strongly to postnatal exposure. Microarray analysis identified 36 differentially expressed hypothalamic transcripts, including genes previously linked to methylation-related pathways. Conclusion: Maternal methyl-donor supplementation is associated with a stable hypothalamic methylation profile established during intrauterine life, while peripheral organs remain epigenetically adaptable. These findings reveal an organ-specific divergence in developmental programming, with exploratory gene expression suggesting functional consequences.