Abstract 15700: Targeted Nanoparticle Delivery of a Protein Arginine Deiminase-4 Inhibitor Limits Arterial Intimal Netosis and Preserves Endothelial Integrity in Mouse Arterial Erosion-like Injury

Abstract

Introduction: Superficial plaque erosion has emerged as a growing cause of residual thrombotic complications of atherosclerosis in an era of effective lipid lowering, anti-hypertensive therapy, and smoking cessation. The mechanisms of plaque erosion remain poorly understood, and we currently lack validated effective diagnostics or therapeutics for superficial erosion. Lesions complicated by erosion have a rich extracellular matrix, sparse lipid, and few mononuclear cells, but do harbor neutrophil extracellular traps (NETs). We recently reported that NETs amplify and propagate the endothelial damage at the site of arterial lesions that recapitulate in mice elements of superficial erosion. We previously showed that genetic loss of protein arginine deiminase (PAD)-4 function inhibited NETosis and preserved endothelial integrity. Hypothesis: We hypothesized that Col IV-targeted NPs (Col IV-NPs) can deliver PAD4 inhibitors selectively to regions of EC sloughing and collagen IV-rich basement membrane exposure, and attenuate the amplification, persistence, and propagation of superficial erosion and consequent thrombosis. Methods: We developed Col IV-NPs to deliver PAD4 inhibitors selectively to regions of endothelial cell sloughing and collagen IV-rich basement membrane exposure using our validated experimental preparation that reproduces in mice some of the conditions ascribed to lesions associated with superficial erosion. Results and Conclusions: We first demonstrated the binding of the targeting ligand in vitro and evaluated Col IV NP targeting towards areas of denuded endothelium in vivo in this mouse preparation. Delivery of the PAD4 inhibitor GSK484 as cargo in these nanoparticles reduced NETs release at sites of eroded areas. Compared to non-targeted NPs, Col IV NPs showed a 1.8-fold increased accumulation at regions of endothelial injury (p<0.0001). When loaded with the PAD4 inhibitor GSK484, Col IV NPs effectively reduced NET accumulation by 2.5 fold at sites of intimal lesions (p<0.01) and preserved endothelial continuity (a 4-fold increase in endothelial continuity percentage, p<0.001). These results indicate the feasibility of using nanotechnology to address the unmet need of specific therapy for superficial erosion.