Effect of low density lipoproteins, high density lipoproteins, and cholesterol on apolipoprotein A-I mRNA in Hep G2 cells》.pdf

Volume 243, number 2, 213-217 FEB 06721 January 1989 Effect of low density lipoproteins, high density lipoproteins, and cholesterol on apolipoprotein A-I mRNA in Hep G2 cells Juan Carlos Monge, Jeffrey M. Hoeg, Simon W. Law and H. Bryan Brewer, jr Molecular Disease Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Building 10, Room 7N117, Bethesda, MD 20892, USA Received 29 November 1988 We have utilized the human hepatoceUular carcinoma cell line, Hep G2, to study the effects of low density iipoproteins (LDL), high density lipoproteins (HDL), and free cholesterol on apolipoprotein (apo) A-I mRNA levels. Incubation of the Hep G2 cells with LDL and free cholesterol led to a significant increase in the cellular content of cholesterol without any effect on the yield of total RNA or in the cellular protein content. Our studies established that incubation with LDL or free cholesterol increased the relative levels of apoA-I mRNA in the Hep G2 cells. In contrast with cholesterol loading, HDL had the effect of lowering the levels of apoA-I mRNA. These results indicate the LDL and HDL pathways as well as intracellular cholesterol may be important in apoA-I gene expression and regulation. HDL; Apolipoprotein A-I 1. INTRODUCTION coordinately linked and the LDL receptor impor- tant in the regulation of apoA-I biosynthesis. In The human hepatocarcinoma cell line Hep G2,