Single-cell trascriptiponal landscapes of bovine peri-implantation development

Supporting healthy pregnancy outcomes requires a comprehensive understanding of the cellular hierarchy and underlying molecular mechanisms during peri-implantation development. Here, we presented a single-cell transcriptome-wide view of the bovine peri-implantation embryo development at day 12, 14, 16 and 18, when most of the pregnancy failure occurs. We defined the development and dynamic progression of cellular composition and gene expression of embryonic disc, hypoblast, and trophoblast lineages during bovine peri-implantation development. Notably, the comprehensive transcriptomic mapping of trophoblast development revealed a previous unrecognized primitive trophoblast cell lineage that are responsible for pregnancy maintenance in bovine prior to the time when binucleate cell emerges. We analyzed novel markers for the cell lineage development during bovine early development. We also identified cell-cell communication signaling underling embryonic and extraembryonic cells interact to ensure proper early development in bovine. Collectively, our work provides foundational information to discover essential biological pathways underpinning bovine peri-implantation development and the molecular causes of the early pregnancy failure during this critical period. Overall design: Single-cell from single elongation embryos were isolated with trypLE, resuspended in 0.04% BSA and analyzed using scRNAseq.