Placenta insufficiency caused by abnormal folate metabolism linked to fetal growth restriction across gestation and generations [RNA-Seq]

Folate is important for fetal development and growth, yet its role in placentation is understudied. Here we report that disrupting folate metabolism by the hypomorphic Mtrr mutation in mice causes morphological and functional defects in their placentas that correspond with early- and late-onset fetal growth restriction. Remarkably, Mtrr heterozygous males initiate inheritance of similar placenta phenotypes and fetal growth defects in their wildtype grandprogeny. An integrated genome-wide approach shows placental transcriptional change and epigenetic instability is caused by an intrinsic or ancestral Mtrr mutation, affecting genes important for placenta development and function (e.g., pregnancy specific glycoprotein (Psg)/Ceacams). Crucially, we establish a functional association between mouse placenta transcript levels and fetal size and identify a human PSG gene variant linked to birthweight. This study provides molecular insight into how folate metabolism influences placental development and attributes a potential multigenerational epigenetic mechanism to unexplained cases of fetal growth defects. Overall design: RNA-seq from E10.5 mouse placentas to assess the intrinsic and ancestral effect of an Mtrrgt allele impairing folate metabolism