Metabolic pathways are transpiring to be significant regulatory sites that participate in controlling stem cell fates. One common feature in stem cell differentiation is the metabolic remodelling from aerobic glycolysis to respiration during the exit from pluripotency, with distinct paths taken by different germ layers. Since glycolytic enzymes have been reproducibly found to associate with RNA, we studied the conserved interaction of enolase 1 (ENO1) with RNA in vitro, in human cells, and during mouse embryonic stem cell differentiation. We show that ENO1 specifically binds RNA targets in human and murine cells. RNA ligands inhibit ENO1’s enzymatic activity in vitro, and ENO1’s enzymatic substrates specifically compete with its RNA binding. Increasing the concentration of RNA ligands in cultured cells inhibits glycolysis. We demonstrate that the differentiation of embryonic stem cells to specific germ layers involves changes in ENO1’s RNA binding. Importantly, pluripotent stem cells expressing an ENO1 mutant that is hyper-inhibited by RNA are severely impaired in their glycolytic capacity and in endodermal differentiation, whereas cells with an RNA binding-deficient ENO1 mutant display disproportionately high endodermal marker expression. The data uncover ENO1 riboregulation as a novel form of metabolic control. They also describe an unprecedented mechanism underlying the regulation of stem cell differentiation.
26/03/2021 Ina Huppertz, European Molecular Biology Laboratory (EMBL)