File:Model neural crest mesenchymal condensation.jpg

Model Pharyngeal Arch Neural Crest Mesenchymal Condensation

A framework of the steps during endochondral ossification in the pharyngeal arch skeletal elements during specification, condensation and overt differentiation.

1. Local BMP and FGF signaling induce prechondrogenic cell fate in neural crest mesenchyme that has migrated to the pharyngeal arches.
2. BMP is required to maintain this fate, which in turn promotes ROCK/Myosin II mediated self-assembly of the mesenchyme, through a combination of tensile force driving cell shape changes.
3. Actomyosin contractions and differential cell cortex tension lead to cell shape changes and the physically mediated regulation of downstream signaling activity of BMP, FGF and reduced TGF-β signaling.
4. These forces are responsible for the size and shape of the condensation, stimulating the nascent cartilage cells to undergo overt differentiation into chondrocytes, which in turn exhibit enhanced BMP, FGF and TGF-β signaling.
5. TGF-β activation of Smad2/3 specifically activates RhoA/ROCK mediated cytoskeletal reorganization and chondrocyte specific gene expression in mesenchyme stem cells.
6. At the point of condensation TGF-β activity must be suppressed in order to maintain prechondrogenic identity, but thereafter, active TGF-β signaling induces overt differentiation into chondrocytes through Smad2/3 mediated signaling.

Links: Neural Crest Development

Reference

<pubmed>26237312</pubmed>| PLoS One.

Copyright

© 2015 Ray, Chapman. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Fig 8. Model of skeletal condensation. Journal.pone.0134702.g008.jpg

doi:10.1371/journal.pone.0134702.g008