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J Clin Invest. 2008 Jun;118(6):2281-90. doi: 10.1172/JCI32561.

Niemann-Pick C1 protects against atherosclerosis in mice via regulation of macrophage intracellular cholesterol trafficking.

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1
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA.

Abstract

Niemann-Pick C1 (NPC1) is a key participant in cellular cholesterol trafficking. Loss of NPC1 function leads to defective suppression of SREBP-dependent gene expression and failure to appropriately activate liver X receptor-mediated (LXR-mediated) pathways, ultimately resulting in intracellular cholesterol accumulation. To determine whether NPC1 contributes to regulation of macrophage sterol homeostasis in vivo, we examined the effect of NPC1 deletion in BM-derived cells on atherosclerotic lesion development in the Ldlr-/- mouse model of atherosclerosis. High-fat diet-fed chimeric Npc1-/- mice reconstituted with Ldlr-/-Npc1-/- macrophages exhibited accelerated atherosclerosis despite lower serum cholesterol compared with mice reconstituted with wild-type macrophages. The discordance between the low serum lipoprotein levels and the presence of aortic atherosclerosis suggested that intrinsic alterations in macrophage sterol metabolism in the chimeric Npc1-/- mice played a greater role in atherosclerotic lesion formation than did serum lipoprotein levels. Macrophages from chimeric Npc1-/- mice showed decreased synthesis of 27-hydroxycholesterol (27-HC), an endogenous LXR ligand; decreased expression of LXR-regulated cholesterol transporters; and impaired cholesterol efflux. Lower 27-HC levels were associated with elevated cholesterol oxidation products in macrophages and plasma of chimeric Npc1-/- mice and with increased oxidative stress. Our results demonstrate that NPC1 serves an atheroprotective role in mice through regulation of LXR-dependent cholesterol efflux and mitigation of cholesterol-induced oxidative stress in macrophages.

PMID:
18483620
PMCID:
PMC2381744
DOI:
10.1172/JCI32561
[Indexed for MEDLINE]
Free PMC Article

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