Effects of alcohol on the transcriptome, methylome, and metabolome of in vitro gastrulating human embryonic cells

Prenatal alcohol exposure (PAE) affects embryonic development, causing a variable fetal alcohol spectrum disorder (FASD) phenotype with neurodevelopmental disorders and birth defects. To explore the effects of PAE on gastrulation, we used an in vitro model with subchronic moderate (20 mM) and severe (70 mM) ethanol exposures during the differentiation of human embryonic stem cells into germ layer cells. We analysed genome-wide gene expression (mRNA sequencing), DNA methylation (EPIC Illumina microarrays), and metabolome (non-targeted LC-MS method) of the endodermal, mesodermal, and ectodermal cells. The largest number of ethanol-induced alterations were observed in the endodermal cells, whereas the most prominent changes were seen in the ectodermal cells. Genes of the major morphogen signaling pathways involved in gastrulation and body patterning were affected by ethanol. Many of the altered genes, such as BMP4 , FGF8 , SIX3, and LHX2 , have been previously associated with PAE and phenotypes of FASD, like defects in heart and corpus callosum development as well as holoprosencephaly. Furthermore, methionine metabolism was altered in all germ layer cells. Our findings support the early origin of alcohol-induced developmental disorders and strengthen the role of methionine cycle in the etiology of FASD.