Reducing macrophage proteoglycan sulfation increases atherosclerosis and obesity through enhanced type I interferon signaling

Gordts PL, Foley EM, Lawrence R, Sinha R, Lameda-Diaz C, Deng L, Nock R, Glass CK, Erbilgin A, Lusis AJ, Witztum JL, Esko JD.  (2014) Reducing macrophage proteoglycan sulfation increases atherosclerosis and obesity through enhanced type I interferon signaling. Cell Metab. 20(5):813-26. PMID: 25440058. PMCID: PMC4254584.

Abstract
Heparan sulfate proteoglycans (HSPGs) are an important constituent of the macrophage glycocalyx and extracellular microenvironment. To examine their role in atherogenesis, we inactivated the biosynthetic gene N-acetylglucosamine N-deacetylase-N-sulfotransferase 1 (Ndst1) in macrophages and crossbred the strain to Ldlr(-/-) mice. When placed on an atherogenic diet, Ldlr(-/-)Ndst1(f/f)LysMCre(+) mice had increased atherosclerotic plaque area and volume compared to Ldlr(-/-) mice. Diminished sulfation of heparan sulfate resulted in enhanced chemokine expression; increased macrophages in plaques; increased expression of ACAT2, a key enzyme in cholesterol ester storage; and increased foam cell conversion. Motif analysis of promoters of upregulated genes suggested increased type I interferon signaling, which was confirmed by elevation of STAT1 phosphorylation induced by IFN-β. The proinflammatory macrophages derived from Ndst1(f/f)LysMCre(+) mice also sensitized the animals to diet-induced obesity. We propose that macrophage HSPGs control basal activation of macrophages by maintaining type I interferon reception in a quiescent state through sequestration of IFN-β.

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