Fetal Matrix Cells (HF)

Fetal matrix cells are lineage-restricted precursors of the inner root sheath (IRS) and hair shaft (HS) layers, organized in proximo-distal columns adjacent to the dermal papilla (DP). Matrix cells undergo asymmetric cell division upon Noggin signaling from the DP, and produce daughter cells for the next layer. In turn, the daughter cells symmetrically divide and generate the layer of post-mitotic cells, located far from the DP, which can undergo terminal differentiation.