Original Article
NF-κB inhibitors that prevent foam cell formation and atherosclerotic plaque accumulation

https://doi.org/10.1016/j.nano.2017.04.013Get rights and content

Abstract

The transformation of monocyte-derived macrophages into lipid-laden foam cells is one inflammatory process underlying atherosclerotic disease. Previous studies have demonstrated that fullerene derivatives (FDs) have inflammation-blunting properties. Thus, it was hypothesized that FD could inhibit the transformation process underlying foam cell formation. Fullerene derivatives inhibited the phorbol myristic acid/oxidized low-density lipoprotein-induced differentiation of macrophages into foam cells as determined by lipid staining and morphology.Lipoprotein-induced generation of TNF-α, C5a-induced MC activation, ICAM-1 driven adhesion, and CD36 expression were significantly inhibited in FD treated cells compared to non-treated cells. Inhibition appeared to be mediated through the NF-κB pathway as FD reduced expression of NF-κB and atherosclerosis-associated genes. Compared to controls, FD dramatically inhibited plaque formation in arteries of apolipoprotein E null mice. Thus, FD may be an unrecognized therapy to prevent atherosclerotic lesions via inhibition of foam cell formation and MC stabilization.

Graphical Abstract

Fullerene derivatives are powerful anti-oxidants capable of significantly reducing the incidence and burden of inflammatory disorders. In the current study we show that fullerene derivatives reduce atherosclerosis of aortic arches of mice as well as a general protective effect when challenged with high fat diets. Taken together, these results are a significant step toward fullerene based therapies for inflammatory diseases.

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Section snippets

Fullerene derivatives

A panel of approximately 30 anti-inflammatory FDs9 were initially tested for their ability to inhibit foam cell formation in vitro. From this initial screen both amphiphilic liposomal malonylfullerene (ALM) and tris-malonate fullerene (C3) were chosen for further analysis. The FDs were bought from Luna Innovations and their formulation is described elsewhere.12, 17

Generation of monocyte-derived macrophage foam cells

Low-density lipoproteins from human plasma were oxidized as previously described to produce ox-LDL.18 To obtain macrophage-derived

Fullerene derivatives

The size distribution profile of ALM and C3 was 0.251 μm and 0.117 μm, respectively while the zeta potentials were −59.02 mV and −95.50 mV, suggesting stability of FD in solution. The size distribution and zeta potential did not significantly change after vigorous vortexing or sonication. Nanosight nanoparticle tracking of ALM and C3 revealed a mean particle size of 0.142 μm for ALM and 0.082 μm for C3. The smaller mean size from the Nanosight is a result of the individualized nature of particle size

Discussion

The aim of our study was to determine if FD could prevent the development of atherosclerosis based on the observation that certain FDs could attenuate other chronic inflammatory diseases.11, 36, 37 After initial testing of several FD, two were chosen for further studies based on their ability to inhibit foam cell formation in vitro. Monocyte U937 cells treated with FD had a significant decrease in total ORO staining under conditions that transform them into foam cells compared to untreated

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    No conflict of interest.

    We acknowledge grants 1R01GM083274-01C and R21 ESO15696-01A and NCBC 2012 BRG1203 to CLK.

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