Insights into the single-cell transcriptome characteristics of porcine endometrium with embryo loss

Reproductive disorders are a concern in the pig industry. Successful gestation processes are closely related to a suitable endometrial microenvironment, and the physiological mechanisms leading to failed pregnancy during the peri-implantation period remain unclear. We constructed single-cell transcriptome profiles of peri-implantation embryo loss and successful gestation endometrial tissues and identified 22 cell subpopulations, with epithelial and stromal cells being the predominant endometrial cell types. The two tissues showed marked differences in cell type composition, especially among epithelial cell subpopulations. We also observed functional differences between epithelial and stromal cells in tissues from embryonic loss and successful gestation, as well as the expression levels and differentiation trajectories of genes associated with embryo attachment and endometrial receptivity in epithelial and stromal cells. The results of cell communication interactions analysis showed that ciliated cells were more active in endometrial tissue with embryo loss, and there were differences in the types of endometrial cells with major roles in embryo loss and embryo implantation successful tissues for bone morphogenic protein, insulin-like growth factor, and transforming growth factor-beta signaling networks associated with embryo implantation. In addition, we compared the functional differences in immune cells between the two tissue types and the expression levels of genes related to the inflammatory microenvironment. Overall, the present study revealed the molecular features of endometrial cell transcription in embryo-lost endometrial tissues, providing deeper insights into the endometrial microenvironment of reproductive disorders, which may inform the etiological, diagnostic, and therapeutic studies of reproductive disorders.