TGF-β signaling controls neural crest developmental plasticity via SMAD2/3 [ATAC-seq]

The neural crest is a highly plastic stem cell population that represents a notable exception to the germ layer theory. Despite being of ectodermal origin, these cells can differentiate into skeletal derivatives like cartilage and bone, tissues that are typically formed by mesoderm. The inductive program that endows the neural crest with these unique properties is still poorly understood. Here, we report that Smad2/3-mediated TGFβ signaling endows cranial neural crest cells with enhanced developmental potential. Our results show that TGFβ signaling modulates neural crest axial identity and directly activates the gene circuits that support skeletal differentiation. Cooperation between TGFβ and low levels of WNT-signaling in the embryonic head activates cranial-specific cis-regulatory elements of anterior genes. Activation of the TGFβ pathway allowed reprogramming of trunk neural crest cells to adopt an anterior identity and led to the development of an improved protocol for the generation of human cranial neural crest cells. Our findings indicate TGFβ signaling is required for the specification of cranial neural crest cells, endowing them with the potential to give rise to the craniofacial skeleton. We performed ATAC-seq analysis on neural crest explant cultures under different TGFB1 and CHIR99021 treatment conditions.