Stromal cells-specific retinoic acid determines parturition timing at single-cell and spatial-temporal resolution.

The underlying mechanisms governing parturition remain largely elusive due to limited knowledge of parturition preparation and initiation. Accumulated evidences indicate that maternal decidua plays a critical role in parturition initiation. To comprehensively decrypt the cell heterogeneity in decidua approaching parturition, we investigate the roles of various cell types in mouse decidua process and reveal previously unappreciated insights in parturition initiation utilizing single-cell RNA sequencing (scRNA-seq). We enumerate the cell types in decidua and identity five different stromal cells populations and one decidualized stromal cells. Furthermore, our study unravels that stromal cells prepare for parturition by regulating local retinol acid (RA) synthesis. RA supplement decreases expression of extracellular matrix-related genes in vitro and accelerates the timing of parturition in vivo. Collectively, the discovery of contribution of stromal cells in parturition expands current knowledge about parturition and opens up avenues for the intervention of preterm birth (PTB).

Traditional Chinese medicine Dingkun Pill facilitates uterine receptivity for implantation in mice†.

Dingkun Pill (DK) is one of the representative traditional Chinese medicines, which has been used in the treatment of gynecological diseases for hundreds of years. Accumulative observations and evidence have shown the beneficial effects of DK, including enhancing the function of hypothalamic-pituitary-ovarian axis. However, the underlying mechanisms remain elusive. In this study, the effects of DK on uterine receptivity and implantation were explored by a series of studies with different mouse models. The results showed that DK can advance the time of implantation by influencing the expression of estrogen target genes to facilitate embryo implantation. DK was efficient to activate embryo implantation at the presence of suboptimal estrogen in delayed implantation mouse model. Our further study revealed that the improvement of DK on receptivity establishment is attributed to the differential regulation of DK on implantation-associated genes. This study provides previously unappreciated molecular mechanism of DK in embryo implantation and benefits the potential clinical application of DK in human reproduction improvement.