Low-density lipoprotein receptor and apolipoprotein A-I and B expression in human enterocytes.
Low-density lipoprotein receptor (LDL-R) was found to be expressed in human small intestine epithelial cells, enterocytes. The relative abundance of LDL-R mRNA and protein was compared with that of apolipoproteins A-I (apoA-I) and B (apoB) in enterocytes and two other cell types: CaCo-2 and HepG2. The LDL-R mRNA content was comparable in three cell types. Human enterocytes expressed 5.2- to 14-fold more apoA-I mRNA than the other cells. In contrast, HepG2 cells expressed 10-to 19-fold more apoB mRNA than CaCo-2 cells and human enterocytes. Immunoprecipitation of [(35)S]methionine pulse-labeled intracellular proteins from these cell types demonstrated that human enterocytes synthesize more apoA-I and apoB, while HepG2 cells synthesize a slightly higher amount of LDL-R.
Molecular Disease Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Md., USA. Dmitri.Sviridov@baker.edu.au
Dmitri
D
Sviridov
Jeffrey M
JM
Hoeg
Thomas
T
Eggerman
Stephen J
SJ
Demosky
Irina G
IG
Safonova
H Bryan
HB
Brewer
D016632:Apolipoprotein A-I / Q000235:genetics* / Q000378:metabolism; D001055:Apolipoproteins B / Q000235:genetics* / Q000378:metabolism; D015152:Blotting, Northern; D004591:Electrophoresis, Polyacrylamide Gel; D020895:Enterocytes / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology; D007421:Intestine, Small / Q000166:cytology*; D008099:Liver / Q000166:cytology; D012333:RNA, Messenger / Q000378:metabolism; D011973:Receptors, LDL / Q000235:genetics* / Q000378:metabolism; D014407:Tumor Cells, Cultured
D016632:Apolipoprotein A-I; D001055:Apolipoproteins B; D012333:RNA, Messenger; D011973:Receptors, LDL