Multifunctional Elastin-Like Polypeptide Fusion Protein Coacervates Inhibit Receptor-Mediated Proinflammatory Signals and Promote Angiogenesis in Mouse Diabetic Wounds

Objective Chronic skin wounds are one of the most devastating complications in diabetic patients due to the formation of advanced glycation end products (AGEs) resulting from non-enzymatic glycation of proteins and lipids in hyperglycemia. AGEs, upon binding their receptors (RAGEs), trigger pro-inflammatory signals that impair wound healing in diabetes and contribute to the pathology of chronic skin wounds. Approach We previously developed a recombinant fusion protein containing the binding domain of RAGE (vRAGE) linked to elastin-like polypeptides (ELPs) that acts as a competitive inhibitor of AGEs, and another ELP fusion protein containing stromal cell-derived factor 1 (SDF1) that promotes revascularization. Herein, we report the effects of protein coacervates incorporating both vRAGE-ELP and SDF1-ELP on wound healing in an in vitro diabetes-mimicking cell culture system, and in in vivo in full-thickness wounds on diabetic mice. Results The combination of vRAGE-ELP and SDF1-ELP increased cell metabolic activity in AGE-stimulated endothelial cells, promoted in vitro tube formation and accelerated healing in an in vitro cell migration assay. When used in a single topical application on full-thickness excisional skin wounds in diabetic mice, wound closure in the combination groups reached almost 100% on post-wounding day 35, compared to 62% and 85% on the same days in animals treated with fibrin gel control and vehicle control consisting of ELP alone. Innovation To our knowledge, this is the first study that attempts to reverse the AGE-RAGE-mediated signaling as well as to promote cell proliferation and vascularization in one single treatment. Conclusion The co-delivery of vRAGE-ELP and SDF1-ELP has potential for the treatment of diabetic wounds.