Reduced Uptake of Oxidized Low-Density Lipoprotein by Macrophages Using Multiple Aptamer Combinations

Abstract

The accumulation of oxidized low-density lipoprotein (oxLDL) in macrophages leads to the formation of foam cells and atherosclerosis development. Reducing the uptake of oxLDL in macrophages decreases the incidence and progression of atherosclerosis. Four distinct single-strand DNA sequences, namely, AP07, AP11, AP25, and AP29, were selected that demonstrated specific binding to distinct regions of oxidized apolipoprotein B100 (apoB100; the protein component of oxLDL) with low HDOCK scores. These four DNA sequences were combined to generate aptamers that selectively bound to labeled Dil-oxLDL, and were subsequently added to murine RAW 264.7 macrophages to test their inhibitory effects using fluorescence spectrometry. The four combined aptamers at 10 μM reduced oxLDL uptake by 79 ± 4% compared to that of the untreated aptamer group. Flow cytometry data demonstrated that macrophages treated with aptamers reached only 32.6% of the Dil-oxLDL signal, a 50% reduction in fluorescence emission relative to that of the untreated group (64.4% Dil-oxLDL signal). Binding the four combined aptamers to the oxLDL surface disrupted the interaction between oxLDL and CD36 via cyclic voltammetry, effectively decreasing the level of uptake of oxLDL by macrophages. Results suggested that these aptamers could be used as alternative compounds to prevent the formation of foam cells, hence providing antiatherosclerosis activity.