Neural crest emigration: From start to stop

Abstract

Within the dynamic context of a developing embryo, the multicellular patterns formed are extraordinarily precise. Through cell-cell communication, neighboring progenitors coordinate their activities, sequentially generating distinct tissues. The development of the dorsal neural tube remarkably illustrates this principle. It first generates neural crest (NC) cells, precursors of most of the peripheral nervous system, and then becomes the roof plate (RP) of the central nervous system. While the molecular network regulating emigration of NC progenitors has been extensively studied, the mechanisms by which dorsal neural tube precursors transit from an initial NC fate to a definitive RP identity remain widely open to investigation. Critical differences exist between premigratory NC and RP cells. Whereas the former extensively proliferate and undergo an epithelial-to-mesenchymal transition that generates cellular migrations, the latter progressively exit the cell cycle and regain epithelial traits including apico-basal polarity and regeneration of a laminin-containing basement membrane. To understand this transition, the nature of the cross-talk between these two sequentially forming progenitor subsets should be unraveled, including the identity and mode of action of signals that, on the one hand, induce the arrest of NC emigration, and, on the other hand, promote formation of a definitive RP.

Rapamycin rescues BMP mediated midline craniosynostosis phenotype through reduction of mTOR signaling in a mouse model

“…Neural crest cells represent a transient cell population capable of self-renewal and multipotency (Crane & Trainor, 2006;Kalcheim, 2018). Cranial neural crest cells arise from the anterior portion of the neural tube and migrate superficially to give rise to the majority of anterior craniofacial structures and differentiate into several different cell types including osteoblasts and chondrocytes (Chen et al, 2017;Mishina & Snider, 2014;Noden & Trainor, 2005).…”

BMP4 patterns Smad activity and generates stereotyped cell fate organisation in spinal organoids

“…In order to gain insight into these mechanisms, we focused on cellular subtypes generated in the dorsal part of the embryonic spinal cord (Kalcheim, 2018;Lai et al, 2016). The spinal cord itself originates from cells of the caudal lateral epiblast (or CLE) that transit through a pre-neural (PNP) state before acquiring a full neurogenic progenitor (NP) state (Gouti et al, 2015;Henrique et al, 2015).…”

“…NP are then directed towards specific neurogenic programmes, depending on their position along the dorso-ventral (D-V) axis of the neural tube ( Fig. 1A) (Kalcheim, 2018;Lai et al, 2016). On the dorsal side, NP comprise 6 pools of discrete cell types, named from dorsal to ventral dp1 to dp6 NP, as well as a group of very dorsal cells that will give rise to neural crest cells (ncc) and the roof plate (rp) (Fig.…”

“…The commitment of NP towards these discrete dorsal fates is determined by the activity of specific combinations of transcription factors (TF), that display stereotypic temporal and spatial profiles of expression ( Fig. 1A) (Kalcheim, 2018;Lai et al, 2016). The profiles of TF marking the ncc, rp, dp1 to dp3 cells are in part generated in response to gradients of diffusing Bone Morphogenetic Proteins (BMPs) secreted first from the non-neural ectoderm, the precursors of ncc and rp cells, then by the rp cells (Kalcheim, 2018;Le Dréau and Martí, 2013;Zagorski et al, 2017).…”

“…1A) (Kalcheim, 2018;Lai et al, 2016). The profiles of TF marking the ncc, rp, dp1 to dp3 cells are in part generated in response to gradients of diffusing Bone Morphogenetic Proteins (BMPs) secreted first from the non-neural ectoderm, the precursors of ncc and rp cells, then by the rp cells (Kalcheim, 2018;Le Dréau and Martí, 2013;Zagorski et al, 2017). Studies using classical developmental approaches led to the model in which the concentration, timing, and duration of BMP exposure are interpreted by PNP and NP cells to guide them towards a specific fate.…”