Single-Cell Transcriptional Landscapes of Bovine Peri-Implantation Development

Abstract

Supporting healthy pregnancy outcomes requires a comprehensive understanding of the cellular hierarchy and underlying molecular mechanisms during peri-implantation development. Here, we present single-cell transcriptomes of bovine peri-implantation embryo development at day 12, 14, 16 and 18, when most pregnancy failure occurs in cattle. We defined the development and dynamic progression of cellular composition and gene expression of embryonic disc, hypoblast, and trophoblast lineages in bovine peri-implantation. Notably, the transcriptomic mapping of trophoblast development revealed a previously unrecognized primitive trophoblast cell lineage that is responsible for pregnancy maintenance in bovine prior to the time when binucleate cells emerge. We analyzed novel markers for the cell lineage development and identified cell-cell communication signaling underling embryonic and extraembryonic cell interaction to ensure proper early development. 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.

Keywords: single cell RNA-seq, bovine peri-implantation, trophoblast, hypoblast, embryonic disc