Lipid peroxidation and oxidant stress regulate hepatic apolipoprotein B degradation and VLDL production.
How omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) lower plasma lipid levels is incompletely understood. We previously showed that marine omega-3 PUFAs (docosahexaenoic acid [DHA] and eicosapentaenoic acid) stimulate a novel pathway, post-ER presecretory proteolysis (PERPP), that degrades apolipoprotein B100 (ApoB100), thereby reducing lipoprotein secretion from liver cells. To identify signals stimulating PERPP, we examined known actions of omega-3 PUFA. In rat hepatoma or primary rodent hepatocytes incubated with omega-3 PUFA, cotreatment with the iron chelator desferrioxamine, an inhibitor of iron-dependent lipid peroxidation, or vitamin E, a lipid antioxidant, suppressed increases in thiobarbituric acid-reactive substances (TBARSs; a measure of lipid peroxidation products) and restored ApoB100 recovery and VLDL secretion. Moreover, omega-6 and nonmarine omega-3 PUFA, also prone to peroxidation, increased ApoB100 degradation via intracellular induction of TBARSs. Even without added fatty acids, degradation of ApoB100 in primary hepatocytes was blocked by desferrioxamine or antioxidant cotreatment. To extend these results in vivo, mice were infused with DHA, which increased hepatic TBARSs and reduced VLDL-ApoB100 secretion. These results establish a novel link between lipid peroxidation and oxidant stress with ApoB100 degradation via PERPP, and may be relevant to the hypolipidemic actions of dietary PUFAs, the basal regulation of ApoB100 secretion, and hyperlipidemias arising from ApoB100 overproduction.
Pan
Meihui
M
The Zena and Michael A. Wiener Cardiovascular Institute and the Department of Medicine, Mount Sinai School of Medicine, New York, New York, USA.
Cederbaum
Arthur I
AI
Zhang
Yuan-Li
YL
Ginsberg
Henry N
HN
Williams
Kevin Jon
KJ
Fisher
Edward A
EA
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001055:Apolipoproteins B / Q000378:metabolism*; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D002614:Chelating Agents / Q000494:pharmacology; D003676:Deferoxamine / Q000494:pharmacology; D004041:Dietary Fats / Q000494:pharmacology; D004281:Docosahexaenoic Acids / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000378:metabolism; D015525:Fatty Acids, Omega-3 / Q000378:metabolism; D005395:Fish Oils / Q000494:pharmacology; D022781:Hepatocytes / Q000166:cytology; D015227:Lipid Peroxidation / Q000187:drug effects*; D008079:Lipoproteins, VLDL / Q000096:biosynthesis*; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018384:Oxidative Stress; D011499:Protein Processing, Post-Translational; D051381:Rats; D013997:Time Factors; D014810:Vitamin E / Q000494:pharmacology
D000975:Antioxidants; D001055:Apolipoproteins B; D002614:Chelating Agents; D004041:Dietary Fats; D015525:Fatty Acids, Omega-3; D005395:Fish Oils; D008079:Lipoproteins, VLDL; D014810:Vitamin E; D004281:Docosahexaenoic Acids; D003676:Deferoxamine