Xanthohumol improves diet-induced obesity and fatty liver by suppressing sterol regulatory element-binding protein (SREBP) activation.
J Biol Chem. 2015 Jul 3. Epub 2015 Jul 3. PMID: 26140926
Sterol regulatory element-binding proteins (SREBPs) are key transcription factors that stimulate the expression of genes involved in fatty acid and cholesterol biosynthesis. Here, we demonstrate that a prenylated flavonoid in hops, xanthohumol (XN), is a novel SREBP inactivator that reduces the de novo synthesis of fatty acid and cholesterol. XN independently suppressed the maturation of SREBPs of insulin-induced genes in a manner different than sterols. Our results suggest that XN impairs the endoplasmic reticulum-to-Golgi translocation of the SREBP cleavage-activating protein (SCAP)/SREBP complex by binding to Sec23/24 and blocking SCAP/SREBP incorporation into common coated protein II vesicles. Furthermore, in diet-induced obese mice, dietary XN suppressed SREBP-1 target gene expression in the liver accompanied by a reduction of the mature form of hepatic SREBP-1 and inhibited the development of obesity and hepatic steatosis. Altogether, our data suggest that XN attenuates the function of SREBP-1 by repressing its maturation and that it has the potential of becoming a nutraceutical food or pharmacological agent for improving metabolic syndrome.