MAFB Overexpression in Macrophages Promotes Wound Healing in Diabetic Foot Ulcer by Transcriptionally Activating WDR74 to Drive a Tissue-Repair Phenotype and Suppress Inflammation and Oxidative Stress.

Diabetic foot ulcer (DFU) represents a significant challenge in clinical management due to its complexity and the impaired wound-healing process associated with diabetes. The role of MAF bZIP transcription factor B (MAFB) in regulating macrophage polarization and its potential impact on DFU healing is an area of growing interest. This study investigates the molecular mechanisms by which MAFB influences diabetic wound healing. MAFB and WD repeat domain 74 (WDR74) protein levels were evaluated using western blotting. mRNA expression of target genes was quantified through quantitative real-time polymerase chain reaction. Flow cytometry was utilized to analyze the proportion of cluster of differentiation 206 (CD206) and CD86-positive cells. Enzyme-linked immunosorbent assays were conducted to measure the concentrations of interleukin-6, tumor necrosis factor-alpha, and interleukin-10. Malondialdehyde production and superoxide dismutase activity were determined using colorimetric assays. Reactive oxygen species levels were quantified with a fluorometric assay. Chromatin immunoprecipitation and dual-luciferase reporter assays were performed to examine the interaction between MAFB and WDR74. Furthermore, a rat model of DFU was established to validate in vivo findings regarding MAFB's role in M2 polarization, inflammation, and oxidative stress. Histological evaluation of wound tissues was performed using hematoxylin and eosin (H&E)and Masson's trichrome staining. The results showed that elevated MAFB levels in LPS-stimulated RAW264.7 macrophages led to a shift towards an M2 phenotype, alongside decreased inflammatory responses and oxidative stress. Mechanistically, MAFB was found to activate the transcription of WDR74 in these macrophages. Notably, WDR74 upregulation promoted M2 polarization and mitigated inflammation and oxidative stress in LPS-treated cells, whereas silencing WDR74 reversed the beneficial effects of MAFB overexpression. Further, in vivo, MAFB promoted wound healing of DFU rats by repressing inflammatory and oxidative stress responses. Thus, MAFB overexpression promoted diabetic foot ulcer healing by fostering a tissue repair phenotype and suppressing inflammation and oxidative stress through the transcriptional activation of WDR74. These findings underscore the potential of MAFB as a therapeutic target for improving diabetic wound healing, which could lead to novel clinical strategies for treating DFUs.