Breviscapine enhances angiogenesis in diabetic wound healing by regulating macrophage polarization via mitochondrial metabolic reprogramming
Description
The impaired angiogenesis driven by persistent inflammatory responses is the pivotal pathogenic step in the progression of diabetic ulcers (DU) to chronic non-healing wounds. Breviscapine has been widely used clinically as an adjunctive therapy for DU, but its precise role and molecular mechanisms in DU reparation remain unclear. The present study aimed at investigating the positive effects and potential mechanism of breviscapine on DU wound healing. We first constructed DU mice model to evaluate the efficacy of breviscapine. The results indicated that breviscapine effectively improved wound skin pathological damage and promoted angiogenesis in DU mice. Breviscapine significantly promoted macrophage polarization toward the pro-reparative M2 phenotype, reduced the secretion of inflammatory cytokines IL-1β and TNF-α, and enhanced the release of anti-inflammatory factor IL-10 and pro-angiogenic factor VEGF in DU mice and HG-induced RAW264.7 cells. Additionally, we treated HUVECs with conditioned medium derived from HG-induced RAW264.7 to examine whether macrophage polarization status affects angiogenesis. Notably, HG-induced RAW264.7 markedly weakened the proliferation, migration, and angiogenic capabilities of HUVECs, which were reversed by breviscapine. Proteomics technology was employed to investigate the potential mechanism by which breviscapine regulated macrophage polarization. Results revealed that in DU mice skin and HG-induced RAW264.7, breviscapine remarkably suppressed the abnormal overexpression of mitochondrial enzyme Arg2, mitigated mitochondrial impairment, and blocked metabolic reprogramming from mitochondrial oxidative phosphorylation to glycolysis, thereby promoting macrophage M2 polarization. To further elucidate the role of Arg2 in the breviscapine protection mechanism, we transfected HG-induced RAW264.7 with plasmid pcDNA3.1-EGFP-Arg2 and siRNA-Arg2. Overexpression of Arg2 in RAW264.7 further aggravated mitochondrial damage and metabolic reprogramming, curtailing M2 polarization, which could be reversed by breviscapine. Meanwhile, breviscapine significantly restored the exacerbated angiogenesis impairment in HUVECs mediated by Arg2 overexpression in RAW264.7 cells. Nevertheless, Arg2 knockdown mimicked the effects of breviscapine, restoring mitochondrial function and OXPHOS metabolism in HG-induced RAW264.7 which facilitated macrophage M2 polarization , thereby exerting a pro-angiogenic impact on HUVECs. Overall, this study demonstrated that breviscapine could promote M2 polarization of macrophages by inhibiting Arg2-mediated mitochondrial metabolic reprogramming, thereby enhancing angiogenesis in DU wound healing.