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Differential Regulation of Liver Gene Expression by in vitro Digested Soy and Caseinate
Author(s) -
Li Jia,
Liu Peter,
Cope Mark,
Crosby Seth,
Napawan Nida,
Krul Elaine S.
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.647.7
Subject(s) - microarray , gene expression , gene , chemistry , hydrolysate , soy protein , microbiology and biotechnology , digestion (alchemy) , pepsin , in vitro , cholesterol , s100a8 , biology , biochemistry , enzyme , chromatography , hydrolysis
The mechanisms underlying the cholesterol lowering effects of soy protein remain unknown. The current study investigated the gene expression profile of a human liver cell line, HepG2, after 18 hours of exposure to 1 mg/ml soy (S) or caseinate (C) protein. S or C was predigested with pepsin and pancreatin to mimic gastrointestinal digestion. Lovastatin (L) (10 μM) and baseline control (Con) were included. Whole genome expression was profiled using an Illumina® microarray. Results indicated that 268 genes were regulated by either S and/or C versus Con, with the patterns of regulation observed being unique to the protein hydrolysate studied. Real‐time quantitative PCR (RT‐qPCR) experiments were conducted using a subset of genes differentially expressed by microarray with a focus on genes that regulate lipid metabolism. RT‐qPCR confirmed the microarray expression profiles observed for L and showed similar trends for S and C compared to Con. RT‐qPCR results showed that the MYLIP gene, whose protein product is responsible for LDL‐R degradation, decreased in HepG2 cells after S treatment compared to Con (0.45 ± 0.076 fold, p = 0.002) or C (0.55 ± 0.092, p = 0.018), with no significant difference between C and Con. Therefore, the cholesterol lowering effect of soy protein may partially be due to increased liver cholesterol uptake as a result of decreased LDL‐R degradation. Funded by Solae, LLC