Investigating the relationship between cell fate and collective cell migration in hair follicle morphogenesis

Abstract

Various processes of life such as development, wound healing, and cancer metastasis depend on collective cell movement, where cells that are connected with each other and exhibit shared cellular polarity move in a collective manner. The skin tissue, in particular, is a site where collective cell movement is constantly in play. During embryonic hair follicle development, hair placodes comprised of two distinct cell types undergo collective cell rearrangements in a counter-rotational pattern. Previous research has revealed the two cell types have distinct transcriptional profiles, and the presence of both cell types is required for counter-rotational movements. However, how each cell type and its respective transcriptional profile contributes to the counter-rotational movement of the placode is still not known. Here we show that the outer cell fate contributes to the directionality of the collective cell movement during placode polarization. When outer cells are lost, the placode fails to polarize, which usually results from a loss of placode directionality. We additionally show our attempt to eliminate the inner cell fate through manipulation of the dermal condensate, a collection of specified dermal fibroblasts below the placode. While we were unable to deplete the inner cell population nor the dermal condensate, we gained insight on the robustness of the dermal condensate population. Our results demonstrate the interplay necessary between different cell types during a dynamic process of development where cells work together to ensure proper cell specification and tissue morphogenesis. My study brings up interesting aspects of hair follicle development that have yet to be explained. The questions that arise during the study may fuel future research and projects to better understand hair follicle morphogenesis and collective cell movement.