Optogenetic engineered umbilical cord MSC-derived exosomes for remodeling of the immune microenvironment in diabetic wounds and the promotion of tissue repair

Background Angiogenesis and tissue repair in chronic non-healing diabetic wounds remain critical clinical problems. Engineered MSC-derived exosomes have significant potential for the promotion of wound healing. Here, we discuss the effects and mechanisms of eNOS-rich umbilical cord MSC exosomes (UCMSC-exo/eNOS) modified by genetic engineering and optogenetic techniques on diabetic chronic wound repair. Methods Umbilical cord mesenchymal stem cells were engineered to express two recombinant proteins. Large amounts of eNOS were loaded into UCMSC-exo using the EXPLOR system under blue light irradiation. The effects of UCMSC-exo/eNOS on the biological functions of fibroblasts and vascular endothelial cells in vitro were evaluated. Full-thickness skin wounds were constructed on the backs of diabetic mice to assess the role of UCMSC-exo/eNOS in vascular neogenesis and the immune microenvironment, and to explore the related molecular mechanisms. Results eNOS was substantially enriched in UCMSCs- exo by endogenous cellular activities under blue light irradiation. UCMSC-exo/eNOS significantly improved the biological functions of cells after high-glucose treatment and reduced the expression of inflammatory factors and apoptosis induced by oxidative stress. In vivo, UCMSC-exo/eNOS significantly improved the rate of wound closure and enhanced vascular neogenesis and matrix remodeling in diabetic mice. UCMSC-exo/eNOS also improved the inflammatory profile at the wound site and modulated the associated immune microenvironment, thus significantly promoting tissue repair. Conclusion This study provides a novel therapeutic strategy based on engineered stem cell- derived exosomes for the promotion of angiogenesis and tissue repair in chronic diabetic wounds.

Automated summary

Engineered MSC-derived exosomes with high expression of eNOS were shown to improve the biological functions of cells and promote tissue repair in chronic non-healing diabetic wounds. These exosomes significantly enhanced wound closure rate, vascular neogenesis, and matrix remodeling in diabetic mice. They also modulated the inflammatory profile and immune microenvironment at the wound site.