Pore-forming toxin-like protein complex expressed by frog promotes tissue repair

Tissue repair is a highly dynamic process, and the immediate onset of acute inflammation has been considered necessary for repair. Pore-forming proteins are important, both in pathogen invasion and host immunity. However, their roles in wound healing and tissue repair are unclear. βγ-crystallin fused aerolysin-like protein (α-subunit) and trefoil factor (β-subunit) complex (βγ-CAT) is a complex of a bacterial pore-forming toxin aerolysin-like protein and trefoil factor identified in the frog Bombina maxima. In this study, we established mouse cutaneous wound models to explore the effects of βγ-CAT on skin wound healing. βγ-CAT accelerated the healing of full-thickness wounds by improving re-epithelialization. This complex relieved dermal edema and promoted scarless healing. βγ-CAT treatment resulted in a rapid release of IL-1β, which initiated an acute inflammation response in the early stage of healing. Meanwhile, the expression levels of TGF-β1, VEGF, and bFGF and the recruitment of M2 macrophages around the wound significantly increased after βγ-CAT treatment. βγ-CAT protected skin wounds against methicillin-resistant Staphylococcus aureus by improving neutrophil recruitment at the site of the wound. Overall, our results suggest that βγ-CAT can promote tissue repair and protect skin wounds against antibiotic-resistant bacterial infection by triggering the acute inflammatory response. This is the first example that aerolysin-like pore-forming proteins widely existing in plants and animals may act in wound healing and tissue repair.-Gao, Z.-H., Deng, C.-J., Xie, Y.-Y., Guo, X.-L., Wang, Q.-Q., Liu, L.-Z., Lee, W.-H., Li, S.-A., Zhang, Y. Pore-forming toxin-like protein complex expressed by frog promotes tissue repair.