(89c) Wnt/BMP Regulates Multipotency of Neural Crest Stem Cells Via Metabolic and Epigenetic Rewiring

Neural crest (NC) cells are a multipotent stem cell population that give rise to a diverse array of cells in the body, including peripheral neurons, Schwann cells (SC), smooth muscle cells, and melanocytes. Neural crest (NC) induction during embryogenesis takes place in response to two key signaling events: the Wnt pathway that is active at the neural plate border; and BMP signaling from the developing mesoderm. Although multipotent NC cells are thought to change their metabolism during differentiation, yet the specific metabolites and metabolic signals that govern NC multipotency remain speculative. In our lab, we have isolated NC-like stem cells (NCSCs) from adult skin tissue, and have shown that these resemble the NCs that originate during development, including their differentiation potential. However, just like embryonic NCs, skin derived NCs are also transient, and lose their stem cell-like characteristics over time in culture.

In this regard, we mimicked the developmental microenvironment during NC induction and treated the cells will BMP2 and the Wnt agonist CHIR99021 to preserve multipotency of skin-derived NCSCs. Combinatorial Wnt/BMP2 signaling sustained the expression of transient NC genes including Sox10, Pax7, AP2A, HNK1 and TrkC in culture. Subsequently, this treatment enhanced the differentiation of NCSCs to melanocytes, schwann cells and smooth muscle cells, as indicated by increased expression of MITF, KROX20 and αSMA respectively. We discovered that Wnt/BMP signaling rewired the metabolic landscape of NCSCs to confer multipotency. This was achieved by activating anaerobic glycolysis in NCSCs treated with CHIR99021 and BMP2, which increased lactate production, glucose consumption and sensitivity to insulin stimulation. Additionally, we observed that CHIR/BMP2 treatment accelerated enzyme kinetics for the key glycolytic enzymes phosphofructokinase (PFK) and Pyruvate Kinase (PK) in NCSCs. Energy demands of multipotent NCSCs were evaluated by employing the Seahorse ATP Rate assay. Indeed, cells treated with the chemicals derived most of their ATP from glycolysis, and the mitochondrial activity was diminished. Taken, together, this study elucidates how developmental events control carbon metabolism and bioenergetics state of NCs, which is important understanding metabolic disorders arising from dysregulation of NC induction and differentiation during embryogenesis; as well as in maintaining NC multipotency for treatment of demyelinating and other diseases.