出版社：American Society for Biochemistry and Molecular Biology
摘要：Apolipoprotein M (apoM) is a novel apolipoprotein with unknownfunction. In this study, we established a method for isolatingapoM-containing lipoproteins and studied their composition andthe effect of apoM on HDL function. ApoM-containing lipoproteinswere isolated from human plasma with immunoaffinity chromatographyand compared with lipoproteins lacking apoM. The apoM-containinglipoproteins were predominantly of HDL size; 5% of the totalHDL population contained apoM. Mass spectrometry showed thatthe apoM-containing lipoproteins also contained apoJ, apoA-I,apoA-II, apoC-I, apoC-II, apoC-III, paraoxonase 1, and apoB.ApoM-containing HDL (HDLapoM+) contained significantly morefree cholesterol than HDL lacking apoM (HDLapoM–) (5.9± 0.7% vs. 3.2 ± 0.5%; P < 0.005) and was heterogeneousin size with both small and large particles. HDLapoM+ inhibitedCu2+-induced oxidation of LDL and stimulated cholesterol effluxfrom THP-1 foam cells more efficiently than HDLapoM–.In conclusion, our results suggest that apoM is associated witha small heterogeneous subpopulation of HDL particles. Nevertheless,apoM designates a subpopulation of HDL that protects LDL againstoxidation and stimulates cholesterol efflux more efficientlythan HDL lacking apoM.Abbreviations: apoM, apolipoprotein M; HRP, haptoglobin-related protein; PON1, paraoxonase 1
Supplementary key words cholesterol efflux • oxidation • apoM
5% of the total HDL population contained apoM. Mass spectrometry showed that the apoM-containing lipoproteins also contained apoJ, apoA-I, apoA-II, apoC-I, apoC-II, apoC-III, paraoxonase 1, and apoB. ApoM-containing HDL (HDLapoM+) contained significantly more free cholesterol than HDL lacking apoM (HDLapoM–) (5.9 ± 0.7% vs. 3.2 ± 0.5%; P < 0.005) and was heterogeneous in size with both small and large particles. HDLapoM+ inhibited Cu2+-induced oxidation of LDL and stimulated cholesterol efflux from THP-1 foam cells more efficiently than HDLapoM–. In conclusion, our results suggest that apoM is associated with a small heterogeneous subpopulation of HDL particles. Nevertheless, apoM designates a subpopulation of HDL that protects LDL against oxidation and stimulates cholesterol efflux more efficiently than HDL lacking apoM.
Abbreviations: apoM, apolipoprotein M; HRP, haptoglobin-related protein; PON1, paraoxonase 1
Supplementary key words cholesterol efflux • oxidation • apoM
