Cholesterol crystals promote endothelial cell and monocyte interactions via H2O2-mediated PP2A inhibition, NFκB activation and ICAM1 and VCAM1 expression

In the present study, we show that cholesterol crystals induce NF kappa B activation, and ICAM1 and VCAM1 expression via xanthine oxidase-mediated H2O2 production and PP2A inhibition in influencing endothelial cell and monocyte interactions and all these adverse effects of cholesterol crystals could be attenuated by proresolving lipid mediator RvD1. In addition, feeding mice with cholesterol rich diet (CRD) increased xanthine oxidase expression, its activity and H2O2 production leading to PP2A inhibition, NF kappa B activation, and ICAM1 and VCAM1 expression and RvD1 attenuated all these effects of CRD substantially. Furthermore, peripheral blood mononuclear cells (PBMCs) from wild type mice when injected into mice that were fed with CRD or RvD1 + CRD showed increased leukocyte trafficking to arteries of CRD-fed mice as compared to RvD1 + CRD mice. These findings suggest that cholesterol crystals via promoting oxidant stress and inhibiting Ser/Thr phosphatases such as PP2A stimulate NF kappa B activation and ICAM1 and VCAM1 expression, and thereby enhance EC-monocyte interactions. In addition, proresolving lipid mediators such as RvD1 appear to exert their anti-inflammatory effects via countering the adverse effects of cholesterol crystals or CRD.