2E and Supporting Fig. 5). These findings suggest increased β oxidation in Thrsp-overexpressed livers. Interestingly,
expression levels and activities of glucose-6-phosphatase Selleck Afatinib (G6pase), a key gluconeogenic enzyme, were significantly increased in Thrsp-overexpressed livers (Fig. 2E and Supporting Fig. 2E), suggesting that Thrsp may increase the release of glucose from the liver and contribute to type 2 diabetes. To further confirm the lipogenic effect of Thrsp in the liver, hepatic Thrsp expression was silenced by a siRNA-based approach. As expected, liver Thrsp expression was decreased approximately 2-fold at the protein level in db/db mice with Thrsp gene knockdown (Supporting Fig. 6A). Hepatic Thrsp gene silencing significantly reduced hepatic TG content (Supporting Fig. 6B). Thrsp gene knockdown also significantly ameliorated liver steatosis of db/db mice, as evidenced by Metformin morphological changes and Oil Red O staining (Supporting Fig. 6C). Consistently, expression of FAS was also markedly reduced after Thrsp gene knockdown (Supporting Fig. 6A). In addition, coinciding with the amelioration of fatty liver, serum alanine aminotransferase
activity and hepatic interleukin-1 expression were significantly reduced in db/db mice with hepatic Thrsp gene knockdown (Supporting Fig. 7A,B), 上海皓元 suggesting a hepatoprotective effect of Thrsp knockdown on the liver. To determine the role of Thrsp in LXR-induced hepatic lipogenesis, we transfected murine primary hepatocytes with si-Thrsp or scrambled siRNA. Six hours after transfection, cells were treated with TO901317 or dimethyl sulfoxide for 36 hours. TO901317 significantly
increased the expression of Thrsp, which was abolished by si-Thrsp transfection (Supporting Fig. 8A). TO901317-induced lipid deposition in hepatocytes was significantly attenuated, but not completely abolished, by the knockdown of Thrsp (Supporting Fig. 8B). TO901317 treatment increased the expression of SREBP-1, FAS, and ACC, and Thrsp gene silencing markedly reduced ACC expression with a declining trend in SREBP-1 and FAS expression (Supporting Fig. 8C). These results imply that Thrsp mediates, at least in part, the lipogenic effects of LXR activation in hepatocytes and further supports our conclusion that Thrsp promotes hepatic lipogenesis. Because activation of the NR, LXR, also leads to enhanced lipogenesis in the liver, and Thrsp expression is regulated by several NRs,[12, 13, 23] we sought to determine whether LXRs might regulate the expression of Thrsp. Mice were treated with TO901317 (5 mg/kg/day) for 3 days, and TG levels were examined. In line with previous reports, TO901317 treatment resulted in significantly enlarged livers (Supporting Fig.