Apolipoprotein M promotes mobilization of cellular cholesterol in vivo

作者：Elsoe Sara; Christoffersen Christina; Luchoomun Jayraz; Turner Scott; Nielsen Lars Bo^*

来源：Biochimica et Biophysica Acta-Molecular and Cell Biology of Lipids, 2013, 1831(7): 1287-1292.

DOI：10.1016/j.bbalip.2013.04.009

• Apolipoprotein M
• Reverse cholesterol transport
• Cholesterol efflux
• Foam cell
• Atherosclerosis

Objective: The HDL associated apolipoprotein M (apoM) protects against experimental atherosclerosis but the mechanism is unknown. ApoM increases pre beta-HDL formation. We explored whether plasma apoM affects mobilization of cholesterol from peripheral cells in mice.
Methods and results: ApoM-enriched HDL from apoM-transgenic mice increased the in vitro efflux of H-3-cholesterol from macrophages by 24 +/- 3% (p < 0.05) as compared with HDL from wild type (WT) mice, thus confirming previous findings. However, apoM-free HDL was not poorer than that of WT HDL to mobilize 3H-cholesterol. H-3-cholesterol-labeled foam cells were implanted in the peritoneal cavity of apoM(-/-), WT and apoM-transgenic mice to assess the mobilization of cholesterol from foam cells in vivo and subsequent excretion into feces. The results showed a statistically non-significant trend towards increased mobilization of cellular cholesterol to plasma with increasing plasma apoM. However, the apoM-genotype did not affect the excretion of 3H-cholesterol in feces. Nevertheless, when apoM-/-, apoM-transgenic and WT mice received a constant intravenous infusion of C-13(2)-cholesterol/intralipid for 5 h, the rate of enrichment of blood free cholesterol with free C-13(2)-cholesterol was significantly lower (consistent with an increase in flux of unlabeled free cholesterol into the plasma) in the apoM-transgenic (3.0 +/- 0.9 parts per thousand/h) as compared to WT (5.7 +/- 0.9 parts per thousand/h, p < 0.05) and apoM(-/-) (6.5 +/- 0.6 parts per thousand/h, p < 0.01) mice.
Conclusion: The present data indicate that the plasma apoM levels modulate the ability of plasma to mobilize cellular cholesterol, whereas apoM has no major effect on the excretion of cholesterol into feces.

• 出版日期2013-7