Single-cell RNA sequencing reveals distinct gene expression patterns in glucose metabolism of human preimplantation embryos.

Precise regulation of glucose metabolism-related genes is essential for early embryonic development. Although previous research has yielded detailed information on the biochemical processes, little is yet known of the dynamic gene expression profiles in glucose metabolism of preimplantation embryos at a single-cell resolution. In the present study, we performed integrated analysis of single-cell RNA sequencing (scRNA-seq) data of human preimplantation embryos that had been cultured in sequential medium. Different cells in the same embryo have similar gene expression patterns in glucose metabolism. During the switch from the cleavage to morula stage, the expression of glycolysis-related genes, such as glucose transporter genes (solute carrier family 2 (facilitated glucose transporter), member 1 (SLC2A1) and solute carrier family 2 (facilitated glucose transporter), member 3 (SLC2A3) and genes encoding hexokinase, phosphofructokinase, pyruvate kinase and lactate dehydrogenase, is increased. The genes involved in the pentose phosphate pathway are highly expressed at the cleavage stage, generating the reducing power to balance oxidative stress derived from biosynthesis. Expression of the genes involved in the biosynthesis of glycerophospholipids is increased after the morula stage. Nevertheless, the expression of tricarboxylic acid-related genes remains relatively unchanged during the preimplantation stages. In conclusion, we discovered that the gene expression profiles are dynamic according to glucose utilisation in the embryos at different stages, which contributes to our understanding of regulatory mechanisms of glucose metabolism-related genes in human preimplantation embryos.