Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we will assume that you are happy to receive all cookies and you will not see this message again. Click 'Find out more' for information on how to change your cookie settings.

BACKGROUND: Myeloid cells are central to atherosclerotic lesion development and vulnerable plaque formation. Impaired ability of arterial phagocytes to uptake apoptotic cells (efferocytosis) promotes lesion growth and establishment of a necrotic core. The transcription factor interferon regulatory factor (IRF)-5 is an important modulator of myeloid function and programming. We sought to investigate whether IRF5 affects the formation and phenotype of atherosclerotic lesions. METHODS: We investigated the role of IRF5 in atherosclerosis in 2 complementary models. First, atherosclerotic lesion development in hyperlipidemic apolipoprotein E-deficient (ApoE(-/-)) mice and ApoE(-/-) mice with a genetic deletion of IRF5 (ApoE(-/-)Irf5(-/-)) was compared and then lesion development was assessed in a model of shear stress-modulated vulnerable plaque formation. RESULTS: Both lesion and necrotic core size were significantly reduced in ApoE(-/-)Irf5(-/-) mice compared with IRF5-competent ApoE(-/-) mice. Necrotic core size was also reduced in the model of shear stress-modulated vulnerable plaque formation. A significant loss of CD11c(+) macrophages was evident in ApoE(-/-)Irf5(-/-) mice in the aorta, draining lymph nodes, and bone marrow cell cultures, indicating that IRF5 maintains CD11c(+) macrophages in atherosclerosis. Moreover, we revealed that the CD11c gene is a direct target of IRF5 in macrophages. In the absence of IRF5, CD11c(-) macrophages displayed a significant increase in expression of the efferocytosis-regulating integrin-β3 and its ligand milk fat globule-epidermal growth factor 8 protein and enhanced efferocytosis in vitro and in situ. CONCLUSIONS: IRF5 is detrimental in atherosclerosis by promoting the maintenance of proinflammatory CD11c(+) macrophages within lesions and controlling the expansion of the necrotic core by impairing efferocytosis.

Original publication

DOI

10.1161/CIRCULATIONAHA.117.027844

Type

Journal article

Journal

Circulation

Publication Date

19/09/2017

Volume

136

Pages

1140 - 1154

Keywords

CD11c, IRF5, atherosclerosis, efferocytosis, macrophages, Animals, Antigens, CD11c, Aorta, Apolipoproteins E, Atherosclerosis, Bone Marrow Cells, Cells, Cultured, Immunohistochemistry, Integrin beta3, Interferon Regulatory Factors, Lymph Nodes, Macrophages, Mice, Mice, Inbred C57BL, Mice, Knockout, Necrosis, Phagocytosis, Shear Strength