Docosahexaenoic acid regulates serum amyloid A protein to promote lipolysis through down regulation of perilipin.
Docosahexaenoic acid (DHA) increases lipolysis and decreases lipogenesis through several pathways. DHA also enhances the expression of serum amyloid A protein (SAA), a possible lipid metabolism related gene. The question of whether DHA regulates the expression of SAA to affect lipid metabolism and increase lipolysis needs to be demonstrated in human adipocytes. We designed experiments to determine the role of SAA in regulating lipid metabolism in HepG2 cells using microarray technology. In human hepatocytes, recombinant human SAA1 (hSAA1) inhibited the expression of genes related to lipogenesis and promoted the expression of those involved in lipolysis. When human breast adipocytes were treated with hSAA1 or DHA in vitro, the expression of peroxisome proliferator-activated receptor gamma and other lipogenic genes was decreased, whereas the expression of several lipolytic genes was increased. Glycerol release was increased by both SAA and DHA treatments, suggesting that they increased lipolytic activity in human adipocytes. The expression of perilipin, a lipid droplet-protective protein, was decreased, and hormone-sensitive lipase was increased by both of hSAA1 and DHA treatment. We speculate that the mechanism of lipolysis by DHA or SAA is at least partially the result of increased expression of hormone-sensitive lipase and decreased expression of perilipin. Whereas DHA treatment increased expression of hSAA1 in human adipocytes, the DHA-mediated reduction in expression of lipogenesis genes and enhancement of lipolysis may be through the activity of hSAA1. These results may be useful in developing new approaches to reduce body fat deposition.
Department of Animal Science and Technology/Institute of Biotechnology, National Taiwan University, Taipei 106, Taiwan.
Ya C
YC
Wang
Wen H
WH
Kuo
Ching Y
CY
Chen
Hsin Y
HY
Lin
Hsin T
HT
Wu
Bing H
BH
Liu
Chia H
CH
Chen
Harry J
HJ
Mersmann
King J
KJ
Chang
Shih T
ST
Ding
D052438:Adipocytes, White / Q000201:enzymology / Q000378:metabolism; D050156:Adipogenesis; D052436:Adipose Tissue, White / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D002352:Carrier Proteins; D002478:Cells, Cultured; D004281:Docosahexaenoic Acids / Q000008:administration & dosage*; D015536:Down-Regulation; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D056945:Hep G2 Cells; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D050155:Lipogenesis; D008066:Lipolysis; D020411:Oligonucleotide Array Sequence Analysis; D000070778:Perilipin-1; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins; D000685:Serum Amyloid A Protein / Q000235:genetics / Q000502:physiology*; D002787:Sterol Esterase / Q000235:genetics / Q000378:metabolism; D017154:Stromal Cells / Q000378:metabolism
D002352:Carrier Proteins; D015850:Interleukin-6; D000070778:Perilipin-1; D010750:Phosphoproteins; D011994:Recombinant Proteins; C521404:SAA1 protein, human; D000685:Serum Amyloid A Protein; D004281:Docosahexaenoic Acids; D002787:Sterol Esterase