Exosomal miRNA-218–5p derived from low-passage dermal papilla cells modulates hair follicle growth and development

Exosomes are nanoscale particles that participate in multiple biological processes and are secreted by various cell types. Exosomes derived from dermal papilla cells (DPC-Exos) regulate hair follicle (HF) growth and development. In this study, HF development-related genes were significantly expressed in low-passage dermal papilla cells (DPCs). Low-passage DPC-Exos promoted hair follicle stem cell (HFSC) proliferation. After the collection of DPC-Exos, miRNA sequencing identified 36 differentially expressed (DE) miRNAs between low-passage and high-passage DPC-Exos. Among these, miR-218-5p was significantly upregulated in low-passage DPC-Exos and dysregulated HF growth and development-related gene expression in HFSCs. Furthermore, the transport mechanism of exosomal miR-218-5p from DPCs is into HFSCs was verified. RNA sequencing of HFSCs treated with exosomal miR-218-5p identified differentially expressed genes (DEGs). The results indicated involvement of miR-218-5p in signaling pathways related to HF growth and development. Additionally, <i>in vitro</i> HF organ culture experiments demonstrated that exosomal miR-218-5p actively promotes hair growth. In summary, low-passage DPC-Exos enhance HFSC proliferation. Exosomal miR-218-5p may serve as a biomarker and therapeutic target for human hair disorders and as a tool to improve wool production in mammals.