MFGE8-primed fibroblasts reprogram the immunosuppressed microenvironment to promote diabetic wound healing.

BACKGROUND

Chronic diabetic ulcers exhibit a dysregulated immune microenvironment characterized by aberrant leukocyte responses and dysfunctional fibroblast activation. Identifying molecular regulators of fibroblast-driven immune responses may provide therapeutic targets to restore effective wound repair in these chronic wounds.

METHODS

Bulk RNA-seq (GSE199939) and scRNA-seq (GSE165816) datasets from human DFUs were integrated to identify alterations in MFGE8 expression in wound fibroblasts. These findings were validated by immunofluorescence staining and RT-qPCR in db/db mouse wounds. Cytokine screening assays were performed to identify upstream regulators of MFGE8 dysregulation. The effects of MFGE8 on fibroblast immune activity were assessed by RT-qPCR, Western blotting, ELISA, and Transwell migration assays. To evaluate its therapeutic potential in vivo, a single-dose of MFGE8-prestimulatedd fibroblasts were locally delivered into db/db mouse wounds, followed by wound healing assessment, immunofluorescence staining, and transcriptomic analysis.

RESULTS

MFGE8 was markedly downregulated in fibroblasts from DFUs. TNF-α and IL-1α robustly induced MFGE8 expression in dermal fibroblasts. Recombinant MFGE8 reprogrammed fibroblasts toward a pro-inflammatory phenotype, significantly increasing the expression of IL1B, IL6, CXCL8, CXCL1, and CCL2, and enhancing macrophage migration in vitro. In db/db mice, MFGE8-prestimulated fibroblasts increased macrophage infiltration, activated inflammatory and pro-repair transcriptional programs, and accelerated wound closure.

CONCLUSION

These findings establish MFGE8 as a key regulator of fibroblast inflammatory competence and support a cell-based immunomodulatory strategy to promote healing in chronic diabetic wounds.