OLEIC-ACID STIMULATION OF APOLIPOPROTEIN-B SECRETION FROM HEPG2 AND CACO-2 CELLS OCCURS POSTTRANSCRIPTIONALLY

被引:143
作者
MOBERLY, JB
COLE, TG
ALPERS, DH
SCHONFELD, G
机构
[1] WASHINGTON UNIV,SCH MED,DIV LIPID RES,4566 SCOTT AVE,BOX 8046,ST LOUIS,MO 63110
[2] WASHINGTON UNIV,SCH MED,DIV ATHEROSCLEROSIS,ST LOUIS,MO 63110
[3] WASHINGTON UNIV,SCH MED,DIV GASTROENTEROL,ST LOUIS,MO 63110
关键词
(Human cell culture); Apolipoprotein secretion; Oleic acid;
D O I
10.1016/0005-2760(90)90058-6
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
HepG2 and Caco-2 cells were studied to compare the regulation of liver and intestinal apolipoprotein (apo) biosynthesis and secretion by fatty acids. Incubation with fatty acid consistently stimulated apoB production by both HepG2 and Caco-2 cells. Media concentrations of apoB, determined by radioimmunoassay, were approx. 3-fold greater for cells incubated for 24 h in serum-free medium containing oleic acid bound to albumin than for cells incubated with albumin alone. Oleic acid also resulted in a 2-3-fold accumulation of cellular triacylglycerol for HepG2 cells and Caco-2 cells. Cellular apoB and media and cellular apoA-I concentrations were not affected by oleic acid. Immimoblotting with a monoclonal antibody against human apoB confirmed a greater mass of apoB in media from HepG2 and Caco-2 cells incubated with oleic acid. Radiolabeled apoB-100 was also increased in media from HepG2 and Caco-2 cells incubated with [35S]methionine for 24 h in the presence of oleic acid, suggesting enhanced apoB synthesis. However, apoB mRNA concentrations were unchanged in response to oleic acid. Gel filtration of media by fast protein liquid chromatography (FPLC) revealed a redistribution of apoB from LDL-sized particles to VLDL or chylomicrons in media from Caco-2 cells incubated with oleic acid, whereas apoB remained in LDL for HepG2 cells. ApoA-I in media from HepG2 and Caco-2 cells eluted as free or lipid-poor apoA-I, and the apoA-I distribution was unaltered by incubation with oleic acid. These data demonstrate that HepG2 and Caco-2 cells maintained in supplemented serum-free medium respond to oleic acid by a similar post-transcriptional increase in apoB synthesis, but different packaging of apoB into triacylglycerol-rich lipoproteins. © 1990.
引用
收藏
页码:70 / 80
页数:11
相关论文
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