Nestin as a Marker of Unipotent Embryonic and Adult Progenitors Differentiating into an Epithelial Cell Lineage of the Hair Follicles

This study investigated the role of nestin, an intermediate filament protein, in hair follicle (HF) development and differentiation. The researchers used genetically modified mice to trace nestin-expressing cells during HF morphogenesis and in adult HFs. They discovered that nestin-expressing cells appear in the epithelial layer of embryonic HFs at the peg stage and express keratin 14 (K14) and K5, but not other markers like vimentin or SOX2. In adult HFs, nestin-expressing cells were not marked by K15, which is associated with multipotent stem cells. However, after inducing hair growth by depilation, most outer root sheath (ORS) keratinocytes in the new anagen HFs were derived from nestin-expressing cells. The study concludes that nestin marks unipotent progenitor cells in both embryonic and adult HFs that are capable of differentiating into ORS keratinocytes.