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Compound A from Plantago asiatica essential oils downregulates the expression of SREBP‐2
Author(s) -
Cho Sungyun,
Hong SungJin,
Kim JinYoung,
Lee SungJoon
Publication year - 2009
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.23.1_supplement.353.2
Subject(s) - reductase , sterol regulatory element binding protein , hmg coa reductase , downregulation and upregulation , chromatin immunoprecipitation , chemistry , gene expression , western blot , immunoprecipitation , biochemistry , microbiology and biotechnology , enzyme , biology , gene , promoter
We previously reported the hypocholesterolemic effects of Plantago asitica essntial oils in vivo by suppression of HMG‐CoA reductase. Based on the GC‐MS analysis and in vitro tests, we identified an active hypocholesterolemic compound (compound A) from the essential oils and investigated its cellular mechanism further. The HepG2 cells were treated with the compound A at various concentrations (0, 0.05, 0.1, 0.2, 0.5, 1mM) for 24 hours, then total RNA and proteins were assayed for RT‐PCR and immunoblotting. The expressions of HMG‐CoA reductase and SREBP‐2 were significantly reduced by the treatments, however, the expression of genes in the posttranslational activation of SREBP‐2, including Insig‐1 Insig‐2, SCAP, S1P, and S2P, were marginally altered. Both membrane‐bound and soluble forms of SREBP‐2 were reduced in immunohistochemistry and immunoblotting. In chromatin immunoprecipitation, the compound A decreased the binding of SREBP‐2 on the promoter of HMG‐CoA reductase. These suggest that the compound A suppressed the HMG‐CoA reductase expression by direct downregulation of SREBP‐2.