Intranasal Delivery of E-Selectin Reduces Atherosclerosis in ApoE−/− Mice

Xinhui Li,Marcelo Amar,Ranil De Silva,Kory R Johnson,John M Hallenbeck,Alan T Remaley,Jacqueline A Quandt,Abdel G Elkahloun,Mark Bryant,Alma Zernecke

doi:10.1371/journal.pone.0020620

Abstract

Mucosal tolerance to E-selectin prevents stroke and protects against ischemic brain damage in experimental models of stroke studying healthy animals or spontaneously hypertensive stroke-prone rats. A reduction in inflammation and neural damage was associated with immunomodulatory or “tolerogenic” responses to E-selectin. The purpose of the current study on ApoE deficient mice is to assess the capacity of this stroke prevention innovation to influence atherosclerosis, a major underlying cause for ischemic strokes; human E-selectin is being translated as a potential clinical prevention strategy for secondary stroke. Female ApoE−/− mice received intranasal delivery of E-selectin prior to (pre-tolerization) or simultaneously with initiation of a high-fat diet. After 7 weeks on the high-fat diet, lipid lesions in the aorta, serum triglycerides, and total cholesterol were assessed as markers of atherosclerosis development. We also assessed E-selectin-specific antibodies and cytokine responses, in addition to inflammatory responses that included macrophage infiltration of the aorta and altered gene expression profiles of aortic mRNA. Intranasal delivery of E-selectin prior to initiation of high-fat chow decreased atherosclerosis, serum total cholesterol, and expression of the leucocyte chemoattractant CCL21 that is typically upregulated in atherosclerotic lesions of ApoE−/− mice. This response was associated with the induction of E-selectin specific cells producing the immunomodulatory cytokine IL-10 and immunosuppressive antibody isotypes. Intranasal administration of E-selectin generates E-selectin specific immune responses that are immunosuppressive in nature and can ameliorate atherosclerosis, a major risk factor for ischemic stroke. These results provide additional preclinical support for the potential of induction of mucosal tolerance to E-selectin to prevent stroke.

Highlights

Atherosclerosis is a major cause and contributor to stroke
Delayed type hypersensitivity Previous work from our laboratory demonstrated E-selectin tolerization significantly limits Th1 mediated DTH reactions mounted in rats following sensitization and challenge with human E-selectin [23,27,28]
Our previous studies in multiple preclinical disease models and the current study in atherosclerosis, have all shown that intranasal delivery of E-selectin leads to salutary mechanisms that are safe and effective

Summary

Introduction

With 15 million strokes each year that result in death or permanent disability in 2/3 of cases, stroke is the second leading cause of death and the leading cause of long-term disability worldwide [1] This burden will increase greatly during the two decades due to population aging [2]. Despite decades of intensive research, therapeutic options for acute stroke are still very limited and only a small proportion of patients can benefit from recombinant tissue plasminogen activator, aspirin, or hemispheric decompression [2]. In this regard, alleviating factors contributing to stroke as a preventative measure is critical for lowering stroke-associated mortality or disability. The absorbance of serum from PBS or E-selectin treated mice was as low as the no serum control; whereas the serum levels of OVA-specific IgG and IgG1 were high in OVA immunized mice (data not shown)

Methods

Results

Conclusion