Hypoxia Combined With Substance P Pretreatment of ADSC ‐Exos Promotes Recruitment and Differentiation of EPCs by Activating YAP / TEAD3 to Treat Diabetic Foot Ulcer

Diabetic ulcers are associated with high amputation and mortality rates, significantly impacting patients' life quality. Both hypoxia and substance P (SP) treated-ADSC-Exos promote wound healing and angiogenesis in diabetic foot ulcers. However, the effects of combined hypoxia and SP pretreatment remain unclear. ADSCs were isolated and treated with hypoxia and SP, and then ADSC-Exos were extracted and identified. A diabetic foot ulcer mice model was established and treated with hypoxia plus SP preconditioned ADSC-Exos. Wound area and the expression of CD31 and CD34 in the gastrocnemius muscle were assessed. Endothelial progenitor cells (EPCs) were isolated from healthy and diabetic mice, and the migration capacity, differentiation potential, and tubule formation ability were evaluated. CXCR4 expression in ADSC, ADSC-Exos, and EPCs treated with ADSC-Exos was measured. TFDB prediction, ChIP, and dual-luciferase assays were used to explore TEAD3 transcriptional regulation of CXCR4. ADSC-Exos were isolated successfully. Hypoxia plus SP preconditioned ADSC-Exos improved wound healing and angiogenesis in diabetic mice. In vitro, they also promoted EPC migration, endothelial differentiation, and tube formation. The expression of CXCR4 increased in ADSC and ADSC-Exos treated with hypoxia plus SP, and surface CXCR4 was elevated in EPCs. Knockdown of CXCR4 counteracted the pro-angiogenic effects of hypoxia plus SP treated ADSC-Exos in diabetic mice. Mechanistically, hypoxia/SP activated YAP signaling, promoting TEAD3-mediated transcription of CXCR4, while inhibition of YAP-TEAD interaction reduced CXCR4 expression. Hypoxia combined with SP promotes CXCR4 expression in ADSCs by activating the YAP/TEAD3 signaling pathway, thereby increasing CXCR4 levels in ADSC-Exos, and finally promotes the recruitment and differentiation of EPCs to treat diabetic foot ulcer.