The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland, 4072, Australia.
Nucleic Acids Res. 2010 Jul;38(13):4296-312. doi: 10.1093/nar/gkq180. Epub 2010 Mar 24.
The retinoic acid receptor-related orphan receptor (ROR) alpha has been demonstrated to regulate lipid metabolism. We were interested in the ROR alpha 1 dependent physiological functions in skeletal muscle. This major mass organ accounts for approximately 40% of the total body mass and significant levels of lipid catabolism, glucose disposal and energy expenditure. We utilized the strategy of targeted muscle-specific expression of a truncated (dominant negative) ROR alpha 1 Delta DE in transgenic mice to investigate ROR alpha 1 signaling in this tissue. Expression profiling and pathway analysis indicated that ROR alpha influenced genes involved in: (i) lipid and carbohydrate metabolism, cardiovascular and metabolic disease; (ii) LXR nuclear receptor signaling and (iii) Akt and AMPK signaling. This analysis was validated by quantitative PCR analysis using TaqMan low-density arrays, coupled to statistical analysis (with Empirical Bayes and Benjamini-Hochberg). Moreover, westerns and metabolic profiling were utilized to validate the genes, proteins and pathways (lipogenic, Akt, AMPK and fatty acid oxidation) involved in the regulation of metabolism by ROR alpha 1. The identified genes and pathways were in concordance with the demonstration of hyperglycemia, glucose intolerance, attenuated insulin-stimulated phosphorylation of Akt and impaired glucose uptake in the transgenic heterozygous Tg-ROR alpha 1 Delta DE animals. In conclusion, we propose that ROR alpha 1 is involved in regulating the Akt2-AMPK signaling pathways in the context of lipid homeostasis in skeletal muscle.
维甲酸相关孤儿受体(ROR)α已被证明能调节脂质代谢。我们对 RORα1 在骨骼肌中的生理功能很感兴趣。骨骼肌是人体最大的器官,约占体重的 40%,在脂质分解、葡萄糖摄取和能量消耗方面发挥着重要作用。我们利用肌肉特异性表达截断(显性负)RORα1ΔDE 的转基因小鼠这一策略,研究 RORα1 在该组织中的信号转导作用。表达谱和通路分析表明,RORα影响涉及以下方面的基因:(i)脂质和碳水化合物代谢、心血管和代谢疾病;(ii)LXR 核受体信号转导;(iii)Akt 和 AMPK 信号转导。利用 TaqMan 低密度芯片进行定量 PCR 分析,并结合统计分析(采用经验贝叶斯和 Benjamini-Hochberg 方法)对该分析进行了验证。此外,还利用 Western blot 和代谢谱分析验证了涉及 RORα1 调节代谢的基因、蛋白质和通路(生脂、Akt、AMPK 和脂肪酸氧化)。鉴定的基因和通路与转基因杂合子 Tg-RORα1ΔDE 动物的高血糖、葡萄糖耐量受损、胰岛素刺激的 Akt 磷酸化减弱和葡萄糖摄取受损相一致。总之,我们提出 RORα1 参与调节骨骼肌中脂质稳态背景下的 Akt2-AMPK 信号通路。