Abstract
Diabetic wounds are complicated by underlying peripheral vasculopathy. Reliance on vascular endothelial growth factor (VEGF) therapy to improve perfusion makes logical sense, yet clinical study outcomes on rescuing diabetic wound vascularization have yielded disappointing results. Our previous work has identified that low endothelial phospholipase Cγ2 (PLCγ2) expression hinders the therapeutic effect of VEGF on the diabetic ischemic limb. In this work, guided by single-cell RNA sequencing of human wound edge, we test the efficacy of gene-targeted therapeutic demethylation intending to improve VEGF-mediated neovascularization. PLCγ2 expression was diminished in all five identified diabetic wound-edge endothelial subclusters encompassing arterial, venous, and capillary cells. Such low expression was associated with hypermethylated PLCγ2 promoter. PLCγ2 promoter was also hypermethylated at murine diabetic ischemic wound edge. To specifically demethylate endothelial PLCγ2 promoter during VEGF therapy, a CRISPR-dCas9-based demethylation cocktail was delivered to the ischemic wound edge using tissue nanotransfection (TNT) technology. Demethylation-based upregulation of PLCγ2 during VEGF therapy improved wound tissue blood flow with an increased abundance of von Willebrand factor (vWF)+/PLCγ2+ vascular tissue elements by activating p44/p42-mitogen-activated protein kinase (MAPK) → hypoxia-inducible factor [HIF]-1α pathway. Taken together, TNT-based delivery of plasmids to demethylate the PLCγ2 gene promoter activity led to significant improvements in VEGF therapy for cutaneous diabetic wounds, resulting in better perfusion and accelerated wound closure.