Engineered cytokines target atherosclerotic plaques and locally suppress inflammation

Abstract

Chronic inflammatory diseases are often treated with corticosteroids or TNF blockers to suppress overactive immune responses. However, these immunosuppressants also dampen healthy immune responses to opportunistic pathogens (e.g., respiratory viruses) and are associated with adverse effects. Targeted immunotherapies are needed to provide local immunosuppression without systemic effects. In the context of atherosclerosis, the anti-inflammatory cytokine IL-10 has been shown to suppress vascular inflammation, but its poor pharmacokinetic profile and pleiotropic effects have limited its therapeutic potential. To overcome these challenges, we engineered IL-10 to specifically target atherosclerotic plaques. We accomplished this goal by constructing fusion proteins in which one side is IL-10 and the other side is an antibody fragment (Fab) that binds to protein epitopes of low-density lipoprotein (LDL). In murine models of atherosclerosis, we show that systemically administered Fab-IL-10 constructs bind circulating LDL and hitchhike a ride to atherosclerotic plaques. In a biodistribution study, we observe elevated levels of IL-10 in the aorta but not the lungs of hyperlipidemic mice, indicative of targeted delivery. The targeted Fab-IL-10 constructs significantly reduce aortic immune cell infiltration to levels comparable to healthy mice, whereas non-targeted IL-10 has no therapeutic effect. Mechanistically, we demonstrate that Fab-IL-10 constructs are preferentially taken up by macrophages to exert an anti-inflammatory effect. This platform technology can be applied to a variety of cytokines and shows promise as a potential targeted anti-inflammatory therapy. Supported by the Chicago Immunoengineering Innovation Center, the NIH National Heart, Lung, and Blood Institute, and the American Heart Association.