Rationale Neutrophil extracellular trap (NET) formation promotes vascular damage, thrombosis, and activation of interferon-α-producing plasmacytoid dendritic cells in diseased arteries. Peptidylarginine deiminase inhibition is a strategy that can decrease in vivo NET formation. Objective To test whether peptidylarginine deiminase inhibition, a novel approach to targeting arterial disease, can reduce vascular damage and inhibit innate immune responses in murine models of atherosclerosis. Methods and Results Apolipoprotein-E (Apoe)−/− mice demonstrated enhanced NET formation, developed autoantibodies to NETs, and expressed high levels of interferon-α in diseased arteries. Apoe−/− mice were treated for 11 weeks with daily injections of Cl-amidine, a peptidylarginine deiminase inhibitor. Peptidylarginine deiminase inhibition blocked NET formation, reduced atherosclerotic lesion area, and delayed time to carotid artery thrombosis in a photochemical injury model. Decreases in atherosclerosis burden were accompanied by reduced recruitment of netting neutrophils and macrophages to arteries, as well as by reduced arterial interferon-α expression. Conclusions Pharmacological interventions that block NET formation can reduce atherosclerosis burden and arterial thrombosis in murine systems. These results support a role for aberrant NET formation in the pathogenesis of atherosclerosis through modulation of innate immune responses.

Objective picardial adipose tissue is associated with coronary artery disease, however the causal relationship between perivascular adipose tissue and local atherogenesis is unclear. Methods and Results Apolipoprotein E deficient (ApoE−/−) mice underwent transplantation of visceral or subcutaneous adipose tissue immediately adjacent to the right common carotid artery. Carotid arteries with fat transplants were analyzed for atherosclerosis by surface oil-red-O staining and cross-sectional analysis. Vascular function of the carotid arteries was assessed using pressure myography. Visceral fat transplants were also performed to ApoE−/− mice with neutralization of P-selectin glycoprotein ligand-1 (Psgl-1). Atherosclerosis surface area and lesion thickness were greater in mice receiving the perivascular visceral fat compared to the subcutaneous fat. Mice with visceral fat transplants also displayed more complicated atherosclerotic lesions with evidence of atherothrombosis. Serum Mcp-1 was higher in mice receiving visceral fat transplants compared to subcutaneous transplants. Visceral fat transplantation also caused impaired endothelial-dependent relaxation of the carotid artery. Psgl-1 deficiency or neutralization of Psgl-1 with an anti-Psgl-1 antibody was protective against perivascular visceral adipose tissue-induced atherosclerosis and was associated with reduced Mcp-1 levels. Conclusions Perivascular visceral fat leads to endothelial dysfunction and accelerated atherosclerosis. This proatherogenic effect of perivascular adipose tissue is blocked by neutralization of Psgl-1.