Ferroptosis plays an essential role in the development of diabetes and its complications, suggesting its potential as a therapeutic target. Stem cell-derived extracellular vesicles (EVs) are increasingly being developed as nano-scale drug carriers. The aim of this study was to determine the role of ferroptosis in the pathogenesis of diabetic wound healing and evaluate the therapeutic effects of coenzyme Q10 (Q10)-stimulated exosmes derived from mesenchymal stem cells (MSCs).

Human keratinocytes (HaCaTs) were exposed to high glucose (HG) conditions in vitro to mimic diabetic conditions, and the ferroptosis markers and expression level of acyl-coenzyme A synthase long-chain family member 4 (ACSL4) were determined. Exosomes were isolated from control and Q10-primed umbilical cord mesenchymal stem cells (huMSCs) and characterized by tramsmission electron microscopy and immunofluorescence staining. The HG-treated HaCaTs were cultured in the presence of exosomes derived from Q10-treated huMSCs (Q10-Exo) and their in vitro migratory capacity was analyzed.

Q10-Exo significantly improved keratinocyte viability and inhibited ferroptosis in vitro. miR-548ai and miR-660 were upregulated in the Q10-Exo and taken up by HaCaT cells. Furthermore, miR-548ai and miR-660 mimics downregulated ACSL4-inhibited ferroptosis in the HG-treated HaCaT cells and enhanced their proliferation and migration. However, simultaneous upregulation of ACSL4 reversed their effects. Q10-Exo also accelerated diabetic wound healing in a mouse model by inhibiting ACSL4-induced ferroptosis.

Q10-Exo promoted the proliferation and migration of keratinocytes and inhibited ferroptosis under hyperglycemic conditions by delivering miR-548ai and miR-660. Q10-Exo also enhanced cutaneous wound healing in diabetic mice by repressing ACSL4-mediated ferroptosis.

Epidermal stem cells (ESCs) are primarily located in the basal layer of the epidermis and play a crucial role in wound healing. ESCs-derived exosomes (ESCs-Exo) are emerging as promising candidates for skin regeneration and wound healing. However, the underlying mechanisms remain unclear. This study aims to investigate the role and mechanisms of ESCs-Exo in promoting the proliferation, migration, and collagen synthesis of human skin fibroblasts (HSFBs).

This study generated, isolated, and characterized ESC-Exos. The effects of ESCs-Exo on the proliferation of human skin fibroblasts (HSFBs) were detected via Cell Counting Kit-8 (CCK8), 5-Ethynyl-2'-deoxyuridine (EdU), and Proliferating Cell Nuclear Antigen (PCNA) and Marker of Proliferation Ki-67 (MKI67) gene expression methods. The effect of ESCs-Exo on the migration of HSFBs was detected via a transwell assay and a scratch test. The concentrations of collagen secreted by the HSFBs and the mRNAs of the two kinds of collagen expressed by the HSFBs were analyzed. We also analyzed the phosphorylation of Protein Kinase N1 (PKN1) and the expression of cyclins via western blotting. Finally, the effect of ESCs-Exo on wound healing was verified by animal experiments, and the key genes and signaling pathways of ESCs-Exo were excavated by transcriptomic analysis.

Western blotting revealed that the exosomes of ESCs highly expressed established markers such as Alix, CD63, and CD9. ESC-Exos significantly promoted HSFB proliferation and migration in a dose-dependent manner, as well as HSFB collagen synthesis, and effectively increased the ratio of collagen III/I. In addition, bioinformatics analysis showed that the expression of key gene C-X-C motif chemokine ligand 9 was lower in the ESCs-Exo group, which may promote wound healing by regulating PKN1-cyclin and tumor necrosis factor signaling pathways. Animal experiments demonstrated that ESCs-Exo could reduce inflammation and accelerate wound healing.

In this study, we found that ESCs-Exo may improve wound healing by promoting the proliferation and migration of HSFBs.