Department of Medicine, and Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
Am J Physiol Endocrinol Metab. 2010 May;298(5):E961-70. doi: 10.1152/ajpendo.00655.2009. Epub 2010 Feb 2.
The orphan nuclear receptor small heterodimer partner (SHP) regulates metabolic pathways involved in hepatic bile acid production and both lipid and glucose homeostasis via the transcriptional repression of other nuclear receptors. In the present study, we generated fat-specific SHP-overexpressed transgenic (TG) mice and determined the potential role of SHP activation, specifically in adipocytes, in the regulation of adipose tissue function in response to stressors. We determined in 2 mo-old SHP TG mice body weight, fat mass index, adipose tissues morphology, thermogenic and metabolic gene expression, metabolic rates at baseline and in response to beta adrenergic receptor agonists, and brown fat ultrastructural changes in response to cold exposure (6-48 h). Mice were fed a 10-wk high-fat diet (HFD; 42% fat). Weight gain, fat mass index, adipose tissues morphology, glucose tolerance, and metabolic rates were determined at the end of the feeding. Young TG mice had increased body weight and adiposity; however, their energy metabolism was increased and brown fat function was enhanced in response to cold exposure through the activation of thermogenic genes and mitochondrial biogenesis. SHP overexpression exacerbated the diet-induced obesity phenotype as evidence by marked weight gain over time, increased adiposity, and severe glucose intolerance compared with wild-type mice fed a HFD. In addition, SHP-TG mice fed HFD had decreased diet-induced adaptive thermogenesis, increased food intake, and decreased physical activity. In conclusion, SHP activation in adipocytes strongly affects weight gain and diet-induced obesity. Developing a synthetic compound to antagonize the effect of SHP may prove to be useful in treating obesity.
孤儿核受体小异二聚体伙伴 (SHP) 通过对其他核受体的转录抑制来调节参与肝胆汁酸生成以及脂质和葡萄糖稳态的代谢途径。在本研究中,我们生成了脂肪特异性 SHP 过表达转基因 (TG) 小鼠,并确定了 SHP 激活(特别是在脂肪细胞中)在调节应激反应下脂肪组织功能中的潜在作用。我们在 2 月龄 SHP TG 小鼠中测定了体重、脂肪质量指数、脂肪组织形态、产热和代谢基因表达、基础代谢率和对β肾上腺素能受体激动剂的反应以及冷暴露(6-48 小时)对棕色脂肪超微结构的影响。小鼠喂食 10 周高脂饮食(HFD;42%脂肪)。在喂食结束时测定体重增加、脂肪质量指数、脂肪组织形态、葡萄糖耐量和代谢率。年轻的 TG 小鼠体重增加和肥胖增加;然而,它们的能量代谢增加,棕色脂肪功能在冷暴露下通过产热基因和线粒体生物发生的激活得到增强。与喂食 HFD 的野生型小鼠相比,SHP 过表达加剧了饮食诱导的肥胖表型,表现为随着时间的推移体重显著增加、肥胖增加和严重的葡萄糖不耐受。此外,喂食 HFD 的 SHP-TG 小鼠的饮食诱导适应性产热减少、食物摄入量增加和体力活动减少。总之,脂肪细胞中 SHP 的激活强烈影响体重增加和饮食诱导的肥胖。开发一种合成化合物来拮抗 SHP 的作用可能在治疗肥胖症方面证明是有用的。