Document Detail


Fatty acids liberated from high-density lipoprotein phospholipids by endothelial-derived lipase are incorporated into lipids in HepG2 cells.
MedLine Citation:
PMID:  12553881     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We previously reported that endothelial-derived lipase (EDL) efficiently hydrolyses high-density-lipoprotein-derived phosphatidycholine (HDL-PC). In the present study, we assessed the ability of EDL to supply HepG2 cells with non-esterified fatty acids (NEFA) liberated from HDL-phospholipids. For this purpose, HepG2 cells infected with adenovirus encoding human EDL (EDL-Ad), or with control beta-galactosidase-expressing adenovirus (LacZ-Ad), were incubated with (14)C-HDL-PC. The analysis of the cellular lipids by TLC revealed that EDL overexpression led to an increase in the amount of cellular (14)C-lipids, whereby the label was mainly incorporated into phospholipids and triacylglycerols (TAG). Cells expressing mutant enzymically inactive EDL (MUT-EDL-Ad) contained similar amounts of (14)C-TAG but higher amounts of (14)C-phosphatidylcholine (PC) compared with LacZ-Ad-infected cells. The co-expression of CD36 augmented the EDL-mediated accumulation of (14)C-lipids in HEK-293 cells. The quadrupole MS analysis of the cellular lipids revealed an increased content of PC and TAG in EDL-expressing HepG2 cells compared with MUT-EDL-Ad-expressing and control cells. However, the MUT-EDL-Ad-expressing cells contained more PC than control cells. Additionally, EDL overexpression led to a 2-fold decrease in the amount of fatty acid synthase mRNA and, in turn, a slightly, but significantly, decreased rate of fatty acid (FA) synthesis in HepG2 cells. In the present study, we show for the first time that EDL efficiently supplies HepG2 cells with NEFA derived from HDL-PL, thus affecting cellular lipid composition and FA synthesis.
Authors:
Juliane G Strauss; Marianne Hayn; Rudolt Zechner; Sanja Levak-Frank; Sasa Frank
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Biochemical journal     Volume:  371     ISSN:  0264-6021     ISO Abbreviation:  Biochem. J.     Publication Date:  2003 May 
Date Detail:
Created Date:  2003-04-18     Completed Date:  2003-05-28     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  2984726R     Medline TA:  Biochem J     Country:  England    
Other Details:
Languages:  eng     Pagination:  981-8     Citation Subset:  IM    
Affiliation:
Institute of Molecular Biology, Biochemistry and Microbiology, University of Graz, Heinrichstrasse 31a, Graz A-8010, Austria.
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MeSH Terms
Descriptor/Qualifier:
Cell Line
Endothelium / enzymology
Fatty Acids / biosynthesis,  metabolism*
Humans
Lipase / metabolism*
Lipid Metabolism*
Lipoproteins, HDL / metabolism*
RNA, Messenger / genetics
Reverse Transcriptase Polymerase Chain Reaction
Chemical
Reg. No./Substance:
0/Fatty Acids; 0/Lipoproteins, HDL; 0/RNA, Messenger; EC 3.1.1.3/Lipase
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