Single-cell analysis reveals the metabolic characteristics of porcine trophoblast cells during early pregnancy.

The placenta is a crucial temporary organ during pregnancy, and its normal development is essential for the establishment of pregnancy. The porcine placenta is a non-invasive epitheliochorial placenta, and the implantation period (days 12-30 of pregnancy) serves as a critical junction throughout pregnancy, determining the success of pregnancy. During this period, the placenta undergoes intense cell proliferation and migration, and these processes require substantial energy support. However, the metabolic features of the placenta during this stage remain largely unexplored. This study integrated single-cell data from porcine placentas on days 16, 20, 24, and 28 of pregnancy to elucidate the metabolic landscape of the porcine placenta during early pregnancy. Our results indicate that trophoblast cells are among the most metabolically active cell types in the placenta. Furthermore, trophoblast cells exhibited highly active amino acid metabolism and sphingolipid metabolism, and different trophoblast subclusters had distinct metabolic characteristics. Through Cellchat and MEBOCOST analyses, it was found that different trophoblast subclusters may regulate the normal functions of other trophoblast subclusters via distinct metabolic signals. Additionally, it was found that there is sphingosine-1-phosphate (S1P)-mediated communication between trophoblast cells and endothelial cells (ECs). Our analysis provides new insights into understanding the dynamic changes of trophoblast cell metabolism in early porcine pregnancy and helps us understand the metabolic mechanisms during the development of trophoblast cells at the molecular dynamic level.