Mochizuki Yuko, Maebuchi Motohiro, Kohno Mitsutaka, Hirotsuka Motohiko, Wadahama Hiroyuki, Moriyama Tatsuya, Kawada Teruo, Urade Reiko
Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, and Uji, Kyoto 611-0011, Japan.
J Agric Food Chem. 2009 Feb 25;57(4):1473-80. doi: 10.1021/jf8031793.
In this study, HepG2 cells were treated with short peptides (7S-peptides) derived from highly purified soybean beta-conglycinin (7S), which was free from lipophilic protein, and the effect of the peptide treatment on lipid metabolism was determined. 7S-peptide treatment suppressed the secretion of apolipoprotein B-100 from HepG2 cells into the medium. The 7S-peptides also suppressed the incorporation of (3)H-glycerol and (14)C-acetate into triacylglyceride but not into major phospholipids, such as phosphatidylcholine and phosphatidylethanolamine. Additionally, the synthesis of cholesterol esters was dramatically decreased for 2 h after the addition of the 7S-peptides, whereas the synthesis of cholesterol remained unchanged by 4 h and increased by 8 h after the addition of the 7S-peptides. The cleaved nuclear form of SREBP-2 increased 8 h after the addition of the 7S peptides, suggesting a decrease in intracellular cholesterol levels. Analysis of changes in mRNA expression after 7S-peptide treatment suggested that the 7S-peptides lower the level of cholesterol in the endoplasmic reticulum, increase the mRNA of genes related to beta-oxidation of fatty acids, and increase the synthesis of cholesterol. From these results, it may be concluded that the peptides derived from 7S altered the lipid metabolism to decrease secretion of apolipoprotein B-100-containing lipoprotein from HepG2 cells.
在本研究中，用源自高度纯化的大豆β - 伴大豆球蛋白（7S）的短肽（7S - 肽）处理HepG2细胞，该7S - 肽不含亲脂性蛋白，并测定肽处理对脂质代谢的影响。7S - 肽处理抑制了载脂蛋白B - 100从HepG2细胞分泌到培养基中。7S - 肽还抑制了（3）H - 甘油和（14）C - 乙酸掺入甘油三酯，但不抑制掺入主要磷脂，如磷脂酰胆碱和磷脂酰乙醇胺。此外，添加7S - 肽后2小时，胆固醇酯的合成显著降低，而添加7S - 肽后4小时胆固醇的合成保持不变，8小时后增加。添加7S - 肽8小时后，裂解的核形式的SREBP - 2增加，表明细胞内胆固醇水平降低。对7S - 肽处理后mRNA表达变化的分析表明，7S - 肽降低了内质网中胆固醇的水平，增加了与脂肪酸β - 氧化相关基因的mRNA，并增加了胆固醇的合成。从这些结果可以得出结论，源自7S的肽改变了脂质代谢，以减少含载脂蛋白B - 100的脂蛋白从HepG2细胞的分泌。
