Recombinant human annexin A5 accelerates diabetic wounds healing by regulating skin inflammation

Abstract

One of the key obstacles to the healing of diabetic wound is the persistence of active inflammation. We previously demonstrated the potential of cell-free fat extract (CEFFE) to promote the healing of diabetic wounds, and annexin A5 (A5) is a crucial anti-inflammatory protein within CEFFE. This study aimed to evaluate the therapeutic potential of A5 in diabetic wounds. A5 was loaded into GelMA hydrogels and applied to skin wounds of diabetic mice in vivo. The diabetic wounds with the treatment of GelMA-A5 were observed for 14 days and evaluated by histological analysis. Accessment of inflammation regulation were conducted through anti-CD68 staining, anti-CD86 and anti-CD206 staining, and qRT-PCR of wound tissue. In presence of A5, macrophages stimulated by lipopolysaccharide (LPS) in vitro, and detected through qRT-PCR, flow cytometry, and immunocytofluorescence staining. Besides, epithelial cells were co-cultured with A5 for epithelialization regulation by CCK-8 assay and cell migration assay. A5 could promote diabetic wound healing and regulate inflammations by promoting the transition of macrophages from M1 to M2 phenotype. In vitro experiments demonstrated that A5 exerted a significant effect on reducing pro-inflammatory factors and inhibiting the polarization of macrophages from M0 toward M1 phenotype. A5 significantly promoted the migration of epithelial cells. Annexin A5 has a significant impact on the regulation of macrophage inflammation and promotion of epithelialization.