Exosomes serve as a crucial mediator of epithelial–fibroblast communication during hair follicle morphogenesis in cashmere goats

The formation of dermal condensates (DCs) through fibroblasts is a pivotal event in hair follicle morphogenesis in cashmere goats, a process that intricately involves epithelial-fibroblast communication. Exosomes (Exos), as essential mediators of intercellular communication, have garnered increasing attention in recent years, yet their precise role in hair follicle morphogenesis remains largely unknown. In this study, we focused on isolating and identifying epithelial cell-derived exosomes (Epi-Exos) from Inner Mongolian cashmere goats. Our experiments demonstrated that Epi-Exos could efficiently enter fibroblasts within 12 h of co-culture. Both direct co-culture of epithelial cells with fibroblasts and co-culture with Epi-Exos alone revealed that Epi-Exos promoted fibroblast migration while inhibiting their proliferation, changes that mirror the cellular biological characteristics observed during DC formation. Furthermore, recognizing the abundance of miRNAs carried by Exos, we conducted small RNA sequencing (small RNA-seq) on Epi-Exos. This analysis identified a panel of 54 highly expressed miRNAs within the Epi-Exos, 34 of which were also found to be abundant in fetal skin tissues of Inner Mongolian cashmere goats. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that these miRNAs were significantly enriched in cellular processes and signaling pathways related to hair follicle morphogenesis. Notably, our findings offer new perspectives on the role of miRNAs in Epi-Exos regulating DC formation and hair follicle morphogenesis in cashmere goats, with significant implications for understanding hair follicle development mechanisms and potential clinical or production benefits, including improved cashmere quality and yield through targeted exosome-mediated signaling manipulation.