Adipose mesenchymal stem cell-derived exosomes accelerate skin wound healing via the lncRNA H19/miR-19b/SOX9 axis

It has been reported that adipose mesenchymal stem cells (ADSCs) accelerate wound healing. Moreover, exosomes, which serve as paracrine factors, play a vital role in wound healing. However, the mechanism remains unclear. This research aimed to determine the roles of exosomes derived from ADSCs (ADSC-Exos) in wound skin tissue repair. Flow cytometry and electron microscopy were carried out to identify ADSCs and ADSC-Exos, respectively; RT-qPCR was performed to assess the lncRNA H19 (H19), microRNA19b (miR-19b) and SRY-related high-mobility-group box 9 (SOX9) levels; Western blotting was carried out to evaluate collagen and β-catenin expression; CCK-8, scratch and transwell assays were conducted to evaluate human skin fibroblast (HSF) cell proliferation, migration and invasion, respectively; the potential binding sites between H19 and miR-19b, miR-19b and SOX9 were detected by dual-luciferase reporter gene assay and RIP assay; and H&E staining was conducted to observe skin wound tissues. ADSC-Exos accelerated the proliferation, migration and invasion of HSF cells via H19. H19 acts as a molecular sponge towards miR-19b, which targets SOX9. ADSC-Exos inhibited miR-19b expression via H19, resulting in accelerated HSF proliferation, migration and invasion. ADSC-Exos upregulated SOX9 to activate the Wnt/β-catenin pathway, resulting in accelerated HSF cell proliferation, migration and invasion, and ADSC-Exos promoted skin wound healing via H19 in mice.The high expression of H19 in ADSC-Exos may upregulate SOX9 expression via miR-19b to accelerate wound healing of skin tissues. Our study may provide novel perspectives for therapy to accelerate skin wound healing.