Regulation of cholesterol efflux from macrophages

The lipid efflux pathway is important for both HDL formation and the reverse cholesterol transport pathway. This review is focused on recent findings on the mechanism of lipid efflux and its regulation, particularly in macrophages. Significant progress has been made on understanding the sequence of events that accompany the interaction of apolipoproteins A-I with cell surface ATP-binding cassette transporter A1 and its subsequent lipidation. Continued research on the regulation of ATP-binding cassette transporter A1 and ATP-binding cassette transporter G1 expression and traffic has also generated new paradigms for the control of lipid efflux from macrophages and its contribution to reverse cholesterol transport. In addition, the mobilization of cholesteryl esters from lipid droplets represents a new step in the control of cholesterol efflux. The synergy between lipid transporters is a work in progress, but its importance in reverse cholesterol transport is clear. The regulation of efflux implies both the regulation of relevant transporters and the cellular trafficking of cholesterol.