Cx43 hemichannel-mediated paracrine involves in the promotion of MSCs on skin wound healing.

BACKGROUND: Mesenchymal stem cells (MSCs) exhibit therapeutic potential in wound healing, primarily through their paracrine effects. However, the specific mechanisms underlying these effects remain ambiguous. Connexin 43 (Cx43), the most abundantly expressed connexins in MSCs, forms hemichannels that mediate the paracrine release of small molecules, suggesting a potential role in MSC-mediated wound healing. METHODS: A full-thickness skin wound model was established in mice to investigate the role of Cx43 hemichannels in MSC-mediated wound healing. Wounds were treated with MSC-conditioned medium (MSC CM), Cx43 hemichannel-inhibited medium (18α-GA CM), or control medium (CTRL CM, complete medium). The assessment of wound healing was conducted through histological and immunofluorescence analyses. Besides, macrophages, endothelial cells, and fibroblasts treated with the three media were subjected to in vitro investigations. The underlying mechanisms were investigated using qRT-PCR, Western blotting, and immunofluorescence. RESULTS: MSC CM promoted wound healing partly through Cx43-dependent mechanisms. Cx43 hemichannel-dependent ATP release activated purinergic receptors and the AKT signaling pathway to facilitate macrophage polarization during the inflammatory phase of wound healing. Inhibition of Cx43 hemichannels prevented MSC CM-induced angiogenesis activation and fibroblast migration during the proliferation phase. CONCLUSIONS: Our findings reveal a novel mechanism that MSCs promote wound healing through Cx43 hemichannel-mediated paracrine, mainly ATP secretion. MSC CM facilitates macrophage polarization, angiogenesis, and fibroblast migration, ultimately enhancing tissue repair. Our finding identifies a novel role for Cx43 hemichannels in the process that MSCs facilitate tissue repair and offer a promising therapeutic strategy in clinical applications to improve wound healing.