Mechanisms
HepG2 hepatocytes secrete CETP activity bound mainly to apoA-I and apoA-II, unlike plasma's strong apoA-I skew, alongside a distinct heat-labile lipid-transfer inhibitor tied to apoE particles (Atherosclerosis 1989)
Original title: Secretion of cholesteryl ester transfer protein-lipoprotein complexes by human HepG2 hepatocytes
Using immunoaffinity chromatography, the authors characterized the distribution of cholesteryl ester transfer activity in particles secreted by HepG2 hepatocytes. HepG2-secreted cholesteryl ester transfer activity was associated with apolipoprotein (apo) A-I (58%) and apo A-II (55%), but not apo B or apo E. This contrasts with human plasma, where the authors' previous studies showed most (88%) transfer activity is associated with apo A-I and very little (7%) with apo A-II, suggesting the plasma distribution reflects active remodeling of nascent particles after secretion. The authors also found HepG2 cells secrete a lipid transfer inhibitor activity associated with apo E-containing lipoprotein particles, which was heat labile.
Original abstract
We have employed immunoaffinity chromatography to characterize the distribution of cholesteryl ester transfer activity in particles secreted by HepG2 hepatocytes. HepG2-secreted cholesteryl ester transfer activity is associated with apoprotein (apo) A-I (58%) as well as apo A-II (55%), and is not associated with apo B or E. In contrast, our previous studies have shown that most (88%) cholesteryl ester transfer activity in human plasma is associated with apo A-I whereas very little (7%) is associated with apo A-II. Thus, the distribution of cholesteryl ester transfer activity in plasma particles likely reflects active remodeling of nascent particles in the plasma compartment. Further data suggested that HepG2 cells secrete a lipid transfer inhibitor activity which is associated with apo E-containing lipoprotein particles. This inhibitory activity is heat labile.
Summary written by cetpinhibition.org from the published abstract; figures as published. Page updated 19 August 2026. Methods.