g(m3)-ganglioside and Atherosclerosis

Recently, the atheroprotective role of endogenous GM3 and an atherogenesis-inhibiting effect of exogenous GM3 suggested a possibility of exogenous GM3 being recruited as an anti-atherosclerotic drug. This study seeks to endow exogenous GM3 with atherosclerotic targetability via reconstituted high-density lipoprotein (rHDL), an atherosclerotic targeting drug nanocarrier. Unloaded rHDL, rHDL loaded with exogenous GM3 at a low concentration (GM3

Topics: Animals; Atherosclerosis; Drug Delivery Systems; G(M3) Ganglioside; Humans; Hydrogen-Ion Concentration; Lipid Metabolism; Lipoproteins, HDL; Macrophages; Male; Mice; Mice, Knockout, ApoE; Nanoparticles; Plaque, Atherosclerotic; RAW 264.7 Cells

Topics: Animals; Apolipoproteins E; Atherosclerosis; Cell Line; Endothelial Cells; G(M3) Ganglioside; Human Umbilical Vein Endothelial Cells; Humans; Lipoproteins, LDL; Macrophages; Malondialdehyde; Mice; Monocytes; Oxidation-Reduction; Plaque, Atherosclerotic; RAW 264.7 Cells

In previous studies, we showed that ganglioside levels (GM3 being the main ganglioside) in human aortic intima isolated from atherosclerotic lesions were 5 times greater compared to intima from non-diseased vascular areas. Recently, we found that GM3 and GM3 synthase levels in differentiated in vitro macrophages were five and ten times higher, respectively, compared to freshly isolated human monocytes. In this article, we report that GM3 synthase mRNA levels were significantly higher in differentiated human monocyte-derived macrophages compared to monocytes and in atherosclerotic aorta compared to normal aorta. The depletion of GM3 synthesis in cultured monocyte-derived macrophages with DL-threo-phenyl-2-hexadecanoylamino-3-pyrrolidino-1-propanol, an inhibitor of ganglioside synthesis, delayed the acquisition of CD206 antigen, prevented the loss of CD163 antigen and enhanced anti-inflammatory cytokine (CCL18) secretion. In the current study, we performed purification of CMP-N-acetylneuraminic acid:lactosylceramide alpha2,3-sialyltransferase (GM3 synthase) from Triton X-100 extract of human blood mononuclear cells by immunoaffinity chromatography on Sepharose coupled with anti-GM3 synthase antibody. Comparison with several glycolipid substrates showed high specificity of the purified enzyme for lactosylceramide. The apparent K(M) for lactosylceramide and CMP-NeuAc were 101 and 180 muM, respectively. Analysis of the purified enzyme by SDS-PAGE followed by the anti-GM3 synthase antibody probing detected two bands with apparent molecular masses of 60 and 64 kDa. There were no other protein bands as revealed by Coomassie Blue staining. Thus, ganglioside GM3 may be considered as a physiological modulator of macrophage differentiation in human atherosclerotic aorta. The presented data suggest that up-regulation of GM3 levels is an element of monocyte/macrophage differentiation that provides a tool for control of macrophage accumulation in inflammatory loci.

Topics: Aortic Diseases; Atherosclerosis; Cell Differentiation; G(M3) Ganglioside; Gene Expression Regulation, Enzymologic; Humans; Macrophages; Monocytes; RNA, Messenger; Sialyltransferases