AIMP1-Derived Peptide Secreted from Hair Follicle Stem Cells Activates Dermal Papilla Cells to Promote Hair Growth

The study found that a fragment derived from aminoacyl-tRNA synthetase-interacting multifunctional protein1 (AIMP1) is secreted from hair follicle stem cells (HFSCs) and activates dermal papilla cells (DPCs), which are crucial for hair follicle maintenance. A decrease in AIMP1 levels in hair follicles was associated with hair loss. Hair regrowth in mice induced with AIMP1 was faster than in non-induced mice. The active region of AIMP1 was identified as 41 amino acids (TN41, aa 6-46). This fragment, generated by MMP1, was secreted from Wnt-treated HFSCs to activate DPCs via FGFR2. TN41 activated Akt and ERK, increased β-catenin, and enhanced DPCs activation. It also promoted hair shaft elongation in cultured human hair follicles and improved the hair-inducing activity of cultured DPC spheroids. Therefore, the AIMP1 fragment secreted from HFSCs may stimulate active hair regrowth by activating DPCs.