Abstract TP557: Endothelial Cell Proinflammatory Priming by Amyloidogenic Medin via NFκB and Inflammasome Pathways and Reversal by Monosialoganglioside Nanoliposomes

Abstract

Medin is a common amyloid protein that accumulates in cerebral vessels with aging and cause endothelial dysfunction in human cerebral arterioles. Studying its role in cerebrovascular disease could provide insights on cerebrovascular aging. We aim to test whether medin induces pro-inflammatory priming of endothelial cells (ECs) and probe mechanistic bases, and determine whether monosialoganglioside-containing nanoliposomes (NLGM1), previously shown to protect against AL amyloid vascular dysfunction, would abrogate this response. Methods: Human umbilical vein ECs were treated (20 hours) with physiologic dose of medin (5 μM) or vehicle, and proinflammatory markers IL-1β, caspase-1, IL-8, IL-6, ICAM-1, phospho-NFκB and pro-thrombotic marker plasminogen activator inhibitor-1 (PAI-1) gene and/or protein expressions were measured. In some replicates, medin was co-treated with either specific NFκB small molecule inhibitor RO106-9920 100 μM or NLGM1 (70:20:5% phosphatidylcholine, cholesterol, monosialoganglioside, 1:10 medin:NLGM1 mass ratio). Results: Medin increased gene expression of IL-1β (104.0±30.2x vs. control, p=0.002), IL-8 (5560±1864x, p<0.001), IL-6 (80.4±48x, p<0.001), ICAM-1 (72.0±8.5x, p<0.001) and PAI-1 (5.4±1x, p<0.001) (n=13-44). There were corresponding increases in protein expression as well as increased phospho-NFκB and caspase-1 (Figure). RO106-9920 co-treatment reduced gene expressions of IL-8, IL-6, ICAM-1 and PAI-1 but not IL-1β (versus medin treatment) whereas NLGM1 normalized gene expressions of all cytokines including IL-1β. Conclusions: Medin induced profound proinflammatory and prothrombotic responses in endothelial cells. Both NFκB and inflammasome-mediated mechanisms mediate medin’s vascular priming effects. Medin-induced pathology is a potential new mechanism of aging-related cerebrovascular inflammation. NLGM1 protects against medin’s effects and may represent a new therapeutic approach.