Analysis of early human neural crest development

Abstract

The outstanding migration and differentiation capacities of neural crest cells (NCCs) have fascinated scientists since Wilhelm His described this cell population in 1868. Today, after intense research using vertebrate model organisms, we have gained considerable knowledge regarding the origin, migration and differentiation of NCCs. However, our understanding of NCC development in human embryos remains largely uncharacterized, despite the role the neural crest plays in several human pathologies. Here, we report for the first time the expression of a battery of molecular markers before, during, or following NCC migration in human embryos from Carnegie Stages (CS) 12 to 18. Our work demonstrates the expression of Sox9, Sox10 and Pax3 transcription factors in premigratory NCCs, while actively migrating NCCs display the additional transcription factors Pax7 and AP-2α. Importantly, while HNK-1 labels few migrating NCCs, p75NTR labels a large proportion of this population. However, the broad expression of p75NTR – and other markers - beyond the neural crest stresses the need for the identification of additional markers to improve our capacity to investigate human NCC development, and to enable the generation of better diagnostic and therapeutic tools.

Sox9 plays multiple roles in the lung epithelium during branching morphogenesis

“…Therefore, our results demonstrating disruption of the stabilized microtubule network on the basal side of the lung epithelium in Sox9 LOF lungs, and the disorganized microtubule network observed in Sox9 LOF distal epithelial cells in the in vitro migration assay, may be explained by perturbations in the ECM. Although the link between Sox9 and cell migration/microtubule organization may be indirect, in other systems Sox9 is critical for cell migration, including neural crest cells during development (73) and tumor metastasis in breast, colon, prostate, and melanoma cancers (74)(75)(76)(77). In future studies, it will be pertinent to determine how Sox9 is mechanistically regulating acetylated tubulin and epithelial cell movement during lung branching morphogenesis.…”

Signaling pathways and tissue interactions in neural plate border formation

“…In these embryos, Pax3, Sox9 and Sox10 have been detected in premigratory NC, whereas migrating NC cells additionally expressed Ap2a and Pax7. 73 Importantly, a recent study revealed that NC induction in hESCs is preceded by the expression of NPB markers Pax3, Pax7, Msx1 and Ap2a, shortly after also the NC marker snail2 is detected. This study further demonstrated that NC induction in hESCs requires Wnt/b-Catenin, BMP and FGF signaling, which indicates that the basic mechanisms of early NPB and NC induction are also conserved in humans.…”

Bone morphogenetic protein 4 promotes craniofacial neural crest induction from human pluripotent stem cells

“…The expression of PAX3, SOX9, and SOX10 in premigratory NC cells and that of PAX7, SOX9, AP2a, and p75 NTR in migratory NC cells has been demonstrated in addition to the expression of SOX10 in human embryos (Betters et al, 2010). Overall, these results indicate that SOX10 and other NC marker genes, in addition to p75 NTR and HNK1, are required for the definitive characterization of NC cells in vivo and in vitro.…”

“…However, a previous study reported that both p75 NTR− and p75 NTR+ cells express other NC markers and are able to differentiate into NC cell derivatives in vitro (Curchoe et al, 2010). A further study of migratory NC cells in early human embryos demonstrated that in vivo p75 NTR+ /HNK1 + cells were localized to a small subset of migratory NC cells and cells of the ventral neural tube in vivo (Betters et al, 2010). It is likely that additional markers are required for definitive characterization of NC cell subsets derived hESC cultures.…”

“…Comparison of expression profiles of the 72 genes in NC cells induced by NC or NC-B culture condition demonstrated that both conditions induced the expression of AP2a, MSX1, and (Fig. 2A) MSX2 genes, which are abundant in both early NC and mesenchymal NC cells in pharyngeal arches (Betters et al, 2010, Brunskill et al, 2014, Nelms and Labosky, 2010 (Fig.3, Table S3). Cells induced by the NC culture condition had high expression of the early NC markers, FOXD3 and PAX3, in addition to PAX7, PAX8, SOX10, and SNAI2 (Fig.3, Table S3).…”