Investigating the expression pattern and WNT-dependence of pro-migratory genes during mouse hair placode development

Abstract

Epithelial cell migration is a striking phenomenon in which cells that are tightly adhered in an epithelium, can undergo dynamic movements while generally maintaining their structural morphology. In development, epithelial cell migration can occur without the activation of a full epithelial to mesenchymal transition (EMT), through a “partial-EMT”. Hair follicle morphogenesis is a useful model for studying epithelial cell migration and partial-EMT, because it has been shown to demonstrate EMT characteristic behaviors . In this study, we investigated the spatial expression and WNT-dependence of pro-migratory genes in early hair follicle progenitors. Using hybridization chain reaction to determine gene expression in mouse embryonic skin explants, we identified that Myosin-X (Myo10), Snai2, and S100A9 are upregulated in inner cells of placodes. Our results revealed the previously unknown spatial expression patterns of pro-migratory genes, linking them to a population of cells proven to exhibit migration. Further, our work supports a role for Wnt signaling and/or positional location inside a developing placode in the modulation of these genes. Inner cells must activate a transcriptional program that grants migration among cells closely bound in an epithelium. Our findings start to characterize the expression and regulation of genes involved in a p-EMT-like event resulting in motility. These findings are not only crucial to developmental biologists, but also for cancer research as partial-EMTs are frequently implicated in cancers with increased metastatic potential.