Lactate Enhances Mouse ES Cell Differentiation Toward XEN Cells In Vitro

Metabolism plays a crucial role for cell survival and function; however, recent evidence has implicated it in regulating embryonic development. In the embryo, the inner cell mass undergoes orchestrated cellular divisions resulting in the formation of pluripotent epiblast stem cells and primitive endoderm cells. However, both lineages can be captured in vitro as embryonic stem (ES) cells and extraembryonic endoderm (XEN) cells. Concomitantly, changes in the metabolic profile occurs during development, and are well documented in the embryonic lineages. However, a comprehensive multi-omic analysis of these features in XEN cells remains lacking. We observed that mouse XEN cells exhibited high sensitivity to glycolytic inhibition in addition to maintaining elevated intra- and extracellular lactate levels in vitro. Extraembryonic endoderm cells maintain high lactate levels by increased LDHA activity, and re-routing pyruvate away from the mitochondria resulting in reduced mitochondrial activity due to disruptions in electron transport chain stoichiometry. Importantly, exogenous lactate supplementation or promoting intracellular lactate accumulation enhances XEN differentiation in vitro. These results highlight how lactate contributes to XEN differentiation in vitro and may serve to enhance reprogramming efficiency of cells used for regenerative medicine.