uPAR-Guided Dendrimer Gel Nanoparticles Reprogram Inflammation to Stabilize Atherosclerotic Plaques

Atherosclerosis is characterized by lipid deposition, chronic inflammation, and apoptosis within the arterial wall, leading to plaque progression and instability. Current lipid-lowering therapies fail to fully address residual cardiovascular risk driven by local inflammation and cell death. Here, we report the development of uPA-functionalized, rapamycin-encapsulated dendrimer nanoparticles (G5PM-uPA/RA) that preferentially accumulate in urokinase plasminogen activator receptor (uPAR)-enriched atherosclerotic plaque, including macrophage- and apoptosis-rich lesion microenvironments. G5PM-uPA/RA was constructed by cross-linking reaction-enabled flash nanoprecipitation in a custom-made multi-inlet vortex mixer, followed by thiol-maleimide conjugation of uPA for uPAR-guided targeting. The nanoparticles demonstrated uniform morphology, favorable stability, and efficient rapamycin loading. In vitro, G5PM-uPA/RA exhibited enhanced macrophage uptake (1.3-fold than nontargeted form), sustained intracellular drug retention (2.2-fold than free drug), and effective suppression of inflammatory cytokine TNF-α release (-10%). In vivo biodistribution studies in Ldlr^-/- mice confirmed accumulation of G5PM-uPA/RA in aortic lesions. Four weeks of G5PM-uPA/RA treatment in Ldlr^-/- mice led to significant reduction in plaque burden (-52% in whole aorta, -41% in aortic root), necrotic core size (-68%), proinflammatory cytokines (-59% for TNF-α, -57% for IL-6), and apoptosis (-61%), while promoting fibrous cap thickening (+60%). Importantly, systemic toxicity was not observed. Collectively, these findings demonstrate that G5PM-uPA/RA offers an effective and safe strategy for inflammation modulation and plaque stabilization, providing a promising nanomedicine platform for atherosclerosis therapy.