HDL and an ATP-binding cassette transporter protein (ABCG1) help ensure that the cells lining major arterial blood vessels are able to continue functioning as normal, according to researchers at Columbia University College of Physicians and Surgeons.
In the study, arteries from mice lacking the protein ABCG1 and from mice lacking both ABCA1 and ABCG1 showed decreased endothelial cell-dependent functions when they were analyzed after the mice had been fed a diet that induces atherosclerosis. Further analysis revealed that endothelial cells from these mice had specific molecular defects including an accumulation of cholesterol and cholesterol-related molecules.
A similar role for ABCG1 in preventing the accumulation of cholesterol within cells was observed when human aortic endothelial cells were analyzed. Treatment of these human cells with HDL prevented the accumulation of cholesterol in an ABCG1-dependent manner.
Since ABCG1 is known to promote the efflux of cholesterol from other cell types in a process that involves HDL, the team of investigators suggest that ABCG1 and HDL maintain the function of endothelial cells in mice fed a diet that induces atherosclerosis by promoting the efflux of cholesterol and other related fats.
This study appears in the Journal of Clinical Investigation.