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

## TL;DR

Low-passage dermal papilla cell exosomes, particularly those containing miR-218–5p, promote hair follicle growth and could be used to treat hair disorders or improve wool production.

## Contribution

The study identifies miR-218–5p in low-passage dermal papilla cell exosomes as a novel modulator of hair follicle growth and development.

## Key findings

- Low-passage dermal papilla cell exosomes significantly promote hair follicle stem cell proliferation.
- Exosomal miR-218–5p is upregulated in low-passage cells and affects gene expression in hair follicle stem cells.
- Exosomal miR-218–5p is involved in signaling pathways related to hair follicle growth and promotes hair growth in vitro.

## Abstract

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, in vitro 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.