Mouse placentae generated by in vitro fertilization exhibit altered gene expression, activated hypoxia responses and reduced fitness.

In this study, we utilized single-nucleus RNA sequencing to quantify alterations in the gene expression programs of mouse placentas conceived through in vitro fertilization (IVF). We identified genetic programs exhibiting both global and cell type specific differences between IVF and natural in vivo fertilization groups. Gene set enrichment analysis revealed pathways associated with parietal trophoblast giant cell differentiation and implicated in the regulation of lactation (placental lactogens), along with Hypoxia-inducible factor dependent gene expression. Importantly, IVF-derived conceptuses showed increased abortion rates when their surrogate mothers were exposed to hypoxia (10.5% O2) during pregnancy (from E7.5 to 12.5). Collectively, our findings shed light on the cellular and molecular underpinnings driving differences in pregnancy outcomes associated with these conception methods and indicate that IVF can sensitize embryos to additional stressful events, as proposed by the developmental origin of health and disease hypothesis. Mouse placentas were generated by transferring E3.5 blastocysts conceived either in vivo (FB) or by in vitro fertilization (IVF) into pseudopregnant recipients. On embryonic day 12.5, placentas were collected, flash-frozen, and processed for single-nucleus RNA sequencing. Nuclei were isolated with the Singulator 100, counted, and barcoded using the 10X Genomics Chromium Next GEM Single Cell 3 v3.1 kit. Libraries were sequenced on an Illumina NovaSeq 6000. Data processing included quality control, clustering, and differential gene expression analysis to compare IVF and FB placentas.