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Circ Res. 2014 Jan 31;114(3):421-33. doi: 10.1161/CIRCRESAHA.114.302153. Epub 2013 Dec 2.

Macrophage mitochondrial oxidative stress promotes atherosclerosis and nuclear factor-κB-mediated inflammation in macrophages.

Author information

1
From the Departments of Medicine, Physiology, and Cellular Biophysics, and Pathology and Cell Biology (Y.W., I.T.), and Medical Scientist Training Program (G.Z.W.), Columbia University, New York, NY; and Department of Pathology, University of Washington, Seattle, WA (P.S.R.).

Abstract

RATIONALE:

Mitochondrial oxidative stress (mitoOS) has been shown to correlate with the progression of human atherosclerosis. However, definitive cell type-specific causation studies in vivo are lacking, and the molecular mechanisms of potential proatherogenic effects remain to be determined.

OBJECTIVE:

Our aims were to assess the importance of macrophage mitoOS in atherogenesis and to explore the underlying molecular mechanisms.

METHODS AND RESULTS:

We first validated Western diet-fed Ldlr(-/-) mice as a model of human mitoOS-atherosclerosis association by showing that non-nuclear oxidative DNA damage, a marker of mitoOS in lesional macrophages, correlates with aortic root lesion development. To investigate the importance of macrophage mitoOS, we used a genetic engineering strategy in which the OS suppressor catalase was ectopically expressed in mitochondria (mCAT) in macrophages. MitoOS in lesional macrophages was successfully suppressed in these mice, and this led to a significant reduction in aortic root lesional area. The mCAT lesions had less monocyte-derived cells, less Ly6c(hi) monocyte infiltration into lesions, and lower levels of monocyte chemotactic protein-1. The decrease in lesional monocyte chemotactic protein-1 was associated with the suppression of other markers of inflammation and with decreased phosphorylation of RelA (NF-κB p65), indicating decreased activation of the proinflammatory NF-κB pathway. Using models of mitoOS in cultured macrophages, we showed that mCAT suppressed monocyte chemotactic protein-1 expression by decreasing the activation of the IκB-kinase β-RelA NF-κB pathway.

CONCLUSIONS:

MitoOS in lesional macrophages amplifies atherosclerotic lesion development by promoting NF-κB-mediated entry of monocytes and other inflammatory processes. In view of the mitoOS-atherosclerosis link in human atheromata, these findings reveal a potentially new therapeutic target to prevent the progression of atherosclerosis.

KEYWORDS:

NF-kappa B; atherosclerosis; macrophages; reactive oxygen species

PMID:
24297735
PMCID:
PMC3946745
DOI:
10.1161/CIRCRESAHA.114.302153
[Indexed for MEDLINE]
Free PMC Article

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