Endocrine Abstracts

Obese mothers during pregnancy have been linked with complications of metabolic diseases and long-term health outcomes. Maternal nutrition plays a pivotal role in fetal development and in-utero programming events. Among key micronutrients, vitamin B12 is essential for DNA synthesis and neurological development. Its deficiency has been associated with adverse outcomes, including neural-tube defects, intrauterine growth restriction, and increased risk of metabolic disorders in offspring potentially through epigenetic mechanisms affecting placental function and fetal metabolism. In this study we aim to identify epigenetically regulated genes and miRNAs due to B12 deficiency through comprehensive integrated multi-omics in placental tissues. Human placental tissues (n = 50) from pregnant women (PRiDE Cohort) were profiled for differentially methylated regions (RRBS-seq), differentially expressed genes (RNA-seq) and differentially expressed miRNAs (sRNA-seq) in mothers with sufficient (>150 pmol/l) and deficient B12 (<150 pmol/l) levels adjusting for maternal age, fetal-sex and body mass index. Mothers with vitamin B12 deficiency exhibited higher BMI, lower folate, and elevated fasting glucose and homocysteine levels compared to those with sufficient B12, while gestational age and neonatal characteristics didn’t differ significantly. Integration of placental multi-omics identified extensive molecular alterations, including 14,219 differentially methylated regions, 208 differentially expressed genes, and 46 miRNAs. Forty-three genes were both differentially methylated and expressed, 24 of which were also targeted by 5 miRNAs; an additional 145 genes were miRNA-regulated independently of methylation. qPCR validation confirmed upregulation of ZBTB16 and downregulation of AGPAT5, both correlating with maternal B12 levels. Pathway enrichment highlighted neuronal differentiation, IL6 production, lipid metabolism, complement cascades, and cytoskeletal organization, suggesting a key regulatory role of maternal B12 in placental gene expression and metabolic programming. Our findings reveal epigenetically regulated targets associated with maternal B12 deficiency, highlighting placental epigenomic and transcriptomic changes, with ZBTB16 and AGPAT5 suggesting potential mediation of effects on neurodevelopment and offspring metabolic outcomes.