HMGB1 Accelerates Wound Healing by Promoting the Differentiation of Epidermal Stem Cells via the “HMGB1-TLR4-Wnt/Notch” Axis

<b>Objective:</b> Impairments in the differentiation and migratory capacity of epidermal stem cells (ESCs) are pivotal factors contributing to delayed wound healing. High mobility group box1 (HMGB1) has recently emerged as a potential target for tissue repair. Therefore, we aimed to investigate the role and molecular mechanisms of HMGB1 in ESCs during the wound-healing process. <b>Approach:</b> Initially, we examined the expression of HMGB1 and the differentiation of ESCs in normal skin, normal wounds and chronic wounds. Then, we assessed the ESC migration and differentiation, and the key markers in the Wnt/Notch signaling pathways, after treatment of HMGB1 and inhibitor, and the knockdown of toll-like receptor 4 (TLR4), using scratch assay, qPCR, western blotting, and immunofluorescence. Finally, we conducted mice models to analyze the healing rates and quality <i>in vivo</i>. <b>Results:</b> HMGB1 was decreased across all epidermal layers, and the differentiation of ESCs was hindered in diabetic foot ulcer. <i>In vitro</i>, HMGB1 enhanced both the migration and differentiation of ESCs while stimulating the expression of the Wnt/Notch pathway within ESCs. However, the downregulation of TLR4 negated these effects. Finally, our <i>in vivo</i> experiments provided evidence that HMGB1 facilitates wound healing and epidermis differentiation <i>via</i> TLR4 and Wnt/Notch signaling pathways. <b>Innovation:</b> This study innovatively introduces HMGB1 as a novel target for skin wound healing and elucidates its mechanisms of action. <b>Conclusions:</b> HMGB1 accelerated wound healing by promoting the differentiation of epidermal stem cells through the "HMGB1-TLR4-Wnt/Notch" axis, which reveals a new potential mechanism and target to expedite wound healing.