A novel preclinical strategy for diabetic wound: CITED2-loaded hydrogel spray targeted macrophage reprogramming

Diabetic wounds resent a considerable clinical challenge due to impaired healing, which results from persistent inflammation and dysregulated macrophage polarization. This study identifies CITED2 as a critical regulator of diabetic wound repair, primarily through its role in modulating macrophage plasticity. We demonstrate that CITED2 exhibits phase-specific expression during normal wound healing, and its downregulation in diabetic wounds disrupts the transition from M1 to M2 macrophages. Local administration of recombinant CITED2 protein accelerates wound closure by promoting the shift of macrophages toward the anti-inflammatory M2 phenotype, thereby enhancing re-epithelialization, collagen deposition, and angiogenesis. Transcriptomic analysis reveals that CITED2 potentially mediates the activation of PPAR-γ signaling and the upregulation of anti-inflammatory genes. Further immunofluorescence analysis of wound tissues shows an upregulation of anti-inflammatory genes (IL10, Gpnmb, and Nr1d1) and a downregulation of pro-inflammatory genes (IL-6, IL-1β, and TNF-α). Additionally, in vitro experiments indicate that conditioned medium from CITED2-treated macrophages significantly enhances the proliferation and migration capabilities of endothelial cells and fibroblasts. Notably, short-term CITED2 treatment (3 days) achieves comparable efficacy to a 14-day rhFGF therapy. To facilitate clinical translation, we developed a fibrin-thrombin-PEG hydrogel spray (Fib-Thr-PEG-CITED2) that exhibits favorable anti-inflammatory and hemostatic properties, along with demonstrated biosafety. In diabetic mouse wounds, the Fib-Thr-PEG-CITED2 hydrogel spray shows superior wound healing effects compared to CITED2 alone or Fib-Thr-PEG controls. These findings establish CITED2 as a novel therapeutic target and the Fib-Thr-PEG-CITED2 hydrogel as a potential strategy for diabetic wound management.