Glucose-dependent signalling pathways regulate TE differentiation in bovine embryos

Glucose uptake and metabolism increase markedly during the transition from morula to blastocyst. However, the functional roles of glucose during this process in bovine embryos remain incompletely understood. Here, we demonstrate that glucose specifically modulates trophectoderm (TE) differentiation without affecting the inner cell mass (ICM), acting through Hippo signalling via the hexosamine biosynthetic pathway (HBP) and the pentose phosphate pathway (PPP) rather than glycolysis. Consistently, scRNA-seq analysis reveals that unlike glycolysis-related genes, which show only stage-specific changes, HBP- and PPP-related genes exhibit significant differential expression between the TE and ICM lineages. Furthermore, we found that glucose deprivation does not impair pyruvate uptake or intracellular pyruvate levels in blastocysts, yet it significantly depletes the terminal metabolites of the HBP and PPP. Together, these findings reveal that glucose-dependent regulation of TE differentiation is conserved in bovine embryos.