Epigallocatechin gallate increases the formation of cytosolic lipid droplets and decreases the secretion of apoB-100 VLDL.
Epigallocatechin gallate (EGCG) increases the formation of cytosolic lipid droplets by a mechanism that is independent of the rate of triglyceride biosynthesis and involves an enhanced fusion between lipid droplets, a process that is crucial for their growth in size. EGCG treatment reduced the secretion of both triglycerides and apolipoprotein B-100 (apoB-100) VLDLs but not of transferrin, albumin, or total proteins, indicating that EGCG diverts triglycerides from VLDL assembly to storage in the cytosol. This is further supported by the observed increase in both intracellular degradation of apoB-100 and ubiquitination of the protein (indicative of increased proteasomal degradation) in EGCG-treated cells. EGCG did not interfere with the microsomal triglyceride transfer protein, and the effect of EGCG on the secretion of VLDLs was found to be independent of the LDL receptor. Thus, our results indicate that EGCG promotes the accumulation of triglycerides in cytosolic lipid droplets, thereby diverting lipids from the assembly of VLDL to storage in the cytosol. Our results also indicate that the accumulation of lipids in the cytosol is not always associated with increased secretion of VLDL.
Li
Lu
L
Wallenberg Laboratory for Cardiovascular Research, Göteborg University, Sahlgrenska University Hospital, SE-413 45 Göteborg, Sweden.
Stillemark-Billton
Pia
P
Beck
Caroline
C
Boström
Pontus
P
Andersson
Linda
L
Rutberg
Mikael
M
Ericsson
Johanna
J
Magnusson
Björn
B
Marchesan
Denis
D
Ljungberg
Anna
A
Borén
Jan
J
Olofsson
Sven-Olof
SO
D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D053299:Apolipoprotein B-100; D001055:Apolipoproteins B / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002460:Cell Line; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D050356:Lipid Metabolism / Q000187:drug effects*; D008055:Lipids / Q000097:blood; D008074:Lipoproteins / Q000097:blood; D008079:Lipoproteins, VLDL / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D041681:NIH 3T3 Cells; D000070780:Perilipin-2; D051381:Rats; D011973:Receptors, LDL / Q000187:drug effects / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
D053299:Apolipoprotein B-100; D001055:Apolipoproteins B; D018076:DNA, Complementary; D008055:Lipids; D008074:Lipoproteins; D008079:Lipoproteins, VLDL; D008565:Membrane Proteins; D000070780:Perilipin-2; D011973:Receptors, LDL; D011994:Recombinant Proteins; D002392:Catechin; D006493:Heparin; C045651:epigallocatechin gallate