Measuring the Stiffness of Ex Vivo Mouse Aortas Using Atomic Force Microscopy

Surface engineered polymersomes for enhanced modulation of dendritic cells during cardiovascular immunotherapy

The principle cause of cardiovascular disease (CVD) is atherosclerosis, a chronic inflammatory condition characterized by immunologically complex fatty lesions within the intima of arterial vessel walls. Dendritic cells (DCs) are key regulators of atherosclerotic inflammation, with mature DCs generating pro-inflammatory signals within vascular lesions and tolerogenic DCs eliciting atheroprotective cytokine profiles and regulatory T cell (Treg) activation. Here, we engineered the surface chemistry and morphology of synthetic nanocarriers composed of poly(ethylene glycol)-b-poly(propylene sulfide) copolymers to selectively target and modulate DCs by transporting the anti-inflammatory agent 1, 25-Dihydroxyvitamin D3 (aVD) and ApoB-100 derived antigenic peptide P210. Polymersomes decorated with an optimized surface display and density for a lipid construct of the P-D2 peptide, which binds CD11c on the DC surface, significantly enhanced the cytosolic delivery and resulting immunomodulatory capacity of aVD in vitro. Intravenous administration of the optimized polymersomes achieved selective targeting of DCs in atheroma and spleen compared to all other cell populations, including both immune and CD45- cells, and locally increased the presence of tolerogenic DCs and cytokines. aVD-loaded polymersomes significantly inhibited atherosclerotic lesion development in high fat diet-fed ApoE-/- mice following 8 weeks of administration. Incorporation of the P210 peptide generated the largest reductions in vascular lesion area (~33%, p<0.001), macrophage content (~55%, p<0.001), and vascular stiffness (4.8-fold). These results correlated with an ~6.5-fold increase in levels of Foxp3+ regulatory T cells within atherosclerotic lesions. Our results validate the key role of DC immunomodulation during aVD-dependent inhibition of atherosclerosis and demonstrate the therapeutic enhancement and dosage lowering capability of cell-targeted nanotherapy in the treatment of CVD.