Pectolinarigenin reduces the expression of sterol regulatory element-binding proteins and cellular lipid levels

Sterol regulatory element-binding proteins (SREBPs) are transcription factors that have important roles in the genes involved in lipid biosynthesis. In this study, it was found that the flavonoid pectolinarigenin, reduced the activity of SRE-containing fatty acid synthase (FAS) promoter and the mRNA expressions of SREBP target genes in human hepatoma (Huh-7) cells. Moreover, compared with other flavonoids, pectolinarigenin reduced the mature forms of SREBPs in a dose-dependent manner. The insulin-induced gene (INSIG) and proteasome were not involved in the pectolinarigenin-mediated reduction of mature forms of SREBPs. Pectolinarigenin also reduced the lipid contents in vitro. These results suggest that pectolinarigenin may inhibit lipogenesis through suppressing SREBP activity, at least partially, via the formation of SREBPs mature forms, thereby reducing the expression of their downstream genes related to lipogenesis. To the best of our knowledge, this is the first work that shows how pectolinarigenin affects cellular lipid levels by affecting SREBPs. [GRAPHICS] .