Effect of Quercetin on Non-shivering Thermogenesis and Intestinal Microbial Populations (P06-037-19)

Activation of non-shivering thermogenesis in adipose tissues and alteration in intestinal microbiome have been linked with improved obese condition. With emerging evidences of dietary compounds to prevent obesity, the objective of this study was to examine whether quercetin activates non-shivering thermogenesis in adipose tissues and influences intestinal microbiome, which eventually improves obese condition. Four-week-old C57BL/6 male mice were fed either a low-fat diet (LFD) or a high-fat diet (HFD) with or without 1% quercetin (Q) for 16 weeks. On the completion of the feeding study, brown adipose tissue (BAT), white adipose tissue (WAT), and cecum were collected. Total RNA was extracted from BAT and WAT, and then cDNA was synthesized. The expression of genes that are involved in the regulation of non-shivering thermogenesis such as uncoupling protein 1 (ucp1), cell death-inducing DFFA-like effector A (cidea), peroxisome proliferator-activated receptor gamma (pparγ), pparγ-coactivator 1 alpha (pgc1α), fibroblast growth factor 21 (fgf21), positive regulatory domain containing 16 (prdm16), and T-box protein 1 (tbx1) were determined by a real-time PCR. The expression of the proteins such as UCP1 and AMP-activated protein kinase (AMPK) was assessed by western blot analysis. Microbial populations in cecum were analyzed via the Illumnia MiSeq sequencing platform and QIIME (Quantitative Insights Into Microbial Ecology) Software. Mice fed HFDQ showed reduced body weight and retroperitoneal (R) WAT weight compared to mice fed HFD. Quercetin supplementation increased the expression of ucp1, prdm16, pgc1α, cidea, and tbx1 genes in BAT and RWAT of mice fed HFD. The expression of UCP1 protein and phosphorylation of AMPK were increased. However, browning effect was not observed in other WATs. Mice fed LFDQ and HFDQ exhibited higher relative abundance of Bacteroidetes than mice fed LFD and HFD whereas the relative abundance of Firmicutes was decreased. Quercetin may be a potential dietary compound that increases energy metabolism by activating BAT and attracting beige adipocytes in RWAT. In addition, quercetin-induced energy metabolism may have a correlation with changes of microbial populations in intestine. The work was supported by USDA.