Atherosclerosis is an inflammatory disease associated with the activation of innate immune TLRs and nucleotide-binding oligomerization domain-containing protein (NOD)-like receptor pathways. However, the function of most innate immune receptors in atherosclerosis remains unclear. Here, we show that NOD2 is a crucial innate immune receptor influencing vascular inflammation and atherosclerosis severity. 10-week stimulation with muramyl dipeptide (MDP), the NOD2 cognate ligand, aggravated atherosclerosis, as indicated by the augmented lesion burden, increased vascular inflammation and enlarged lipid-rich necrotic cores in Ldlr-/- mice. Myeloid-specific ablation of NOD2, but not its downstream kinase, receptor-interacting serine/threonine-protein kinase 2, restrained the expansion of the lipid-rich necrotic core in Ldlr-/- chimeric mice. In vitro stimulation of macrophages with MDP enhanced the uptake of oxidized low-density lipoprotein and impaired cholesterol efflux in concordance with upregulation of scavenger receptor A1/2 and downregulation of ATP-binding cassette transporter A1. Ex vivo stimulation of human carotid plaques with MDP led to increased activation of inflammatory signaling pathways p38 MAPK and NF-κB-mediated release of proinflammatory cytokines. Altogether, this study suggests that NOD2 contributes to the expansion of the lipid-rich necrotic core and promotes vascular inflammation in atherosclerosis.
CITATION STYLE
Johansson, M. E., Zhang, X. Y., Edfeldt, K., Lundberg, A. M., Levin, M. C., Borén, J., … Yan, Z. Q. (2014). Innate immune receptor NOD2 promotes vascular inflammation and formation of lipid-rich necrotic cores in hypercholesterolemic mice. European Journal of Immunology, 44(10), 3081–3092. https://doi.org/10.1002/eji.201444755
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