Abstract

https://us06web.zoom.us/j/82089026611?pwd=L2FyclJFL2lYR0J3SFBDbHQyUFp6UT09

Abstract: The interaction between cells and their microenvironments is critical for determining the shape and pattern of tissues. Most mammalian ectodermal appendages, including hair follicles, are formed from the 2D flat epithelial primordia called placodes. However, how these flat disc structures eventually transform into a variety of unique 3D shapes with patterned cellular organization remains largely unknown. We combined live imaging and single-cell transcriptomics to capture a dynamic cell lineage progression and transcriptome changes in the entire epithelium of the mouse hair follicle as it develops. By following single-cells over time, we found that hair placodes are organized into concentric rings of progenitor cell populations, which telescope out to form longitudinally aligned 3D cylindrical functional compartments. Prospective hair follicle stem cells are derived from the peripheral ring of the placode basal layer, where the characteristic state of adult hair follicle stem cells is observed. Combining these findings with previous work on the development of appendages in insects, we provide the ‘telescope model’ for the development of mammalian surface ectodermal organs. To further investigate how extracellular matrix dynamics is involved in this process, we established a live imaging system that allows us to visualise and quantify basement membrane dynamics together with multicellular dynamics. In this talk, I will discuss the mechanisms coupling skin organogenesis with signal and cellular compartmentalization during dynamic morphogenetic events.