SIRT1营养感应的新关键调控因子及其在糖脂代谢稳态调控中的作用和机制研究

SIRT1 plays an important role in regulating glucose and lipid homeostasis as a nutrient-sensing protein. However, the nutrient-sensing signal pathway of SIRT1 and its role and related mechanisms in the development of related diseases are still largely unknown. Especially some key regulators of the nutrient-sensing signal pathway of SIRT1 are yet to be investigated. This project aims to screen nutrient-sensing lncRNA and mRNA by high throughput sequencing with RNA samples from mouse liver and primary hepatocytes under normal, nutrient deficient and over-nutritional status. The differentially expressed lncRNA and mRNA will be validated by quantitative PCR, and subsequently will be applied to screen nutrient-sensing lncRNA and mRNA which affect the in vivo enzyme activity of SIRT1 accompanied with the change of SIRT1 protein level, in vitro enzyme activity of SIRT1, or inracellular NAD+ level. Then the effect of the candidate lncRNA and protein on glucose and lipid homeostasis will be investigated in vitro and in vivo, and whether SIRT1-related mechanisms are involved will also be investigated. This project will identify some novel key regulators of SIRT1 nutrient-sensing signal pathway, reveal their roles in glucose and lipid homeostasis, and elucidate the related molecular mechanisms, which will provide new clues for the prevention and intervention of nutrient-sensing related diseases.

SIRT1作为营养感应蛋白在糖脂代谢的稳态调控中起重要作用。但SIRT1营养感应信号通路及其在疾病中的作用机制还有待进一步阐明，特别是SIRT1上游营养感应的新关键调控因子及其作用机制还有待研究和探索。本项目拟利用高通量测序技术对营养正常、缺乏和过剩状态下的小鼠肝脏组织和原代肝细胞的lncRNA表达谱和mRNA表达谱进行检测、差异分析和实验验证；接着从中筛选可以影响细胞内SIRT1去乙酰化酶活性，并可调节SIRT1蛋白水平、SIRT1体外酶活性或NAD+水平的营养感应lncRNA和蛋白；进而在细胞和动物水平深入研究候选的营养感应lncRNA和蛋白对糖脂稳态的调控作用，并探讨其是否通过SIRT1的相关机制发挥其调控作用。本项目的顺利实施将揭示SIRT1营养感应信号通路的新关键调控因子及其在糖脂代谢稳态调控中的作用和机制，并为营养感应相关疾病的预防和干预提供新的思路和线索。

营养感应，即机体对环境中营养水平的波动进行感知和应答，是生命必备的基本能力，在机体稳态调控方面起着关键作用。SIRT1是一个营养感应的关键蛋白，但其深入的调控机制还有待进一步揭示。本项目揭示了多种营养应激条件下的lncRNA表达谱和mRNA表达谱，发现了一系列SIRT1上游的调控因子。其中发现可以影响SIRT1活性的NAD的降解酶SARM1是糖尿病外周神经病变的治疗靶点，获Diabetes期刊同期专评。研究发现SIRT1营养感应关键调控因子Nmnat2在脑中对于脂代谢有重要调控作用，并揭示相关分子机制。部分工作在2019 Keystone Symposia Conference上作大会报告并发表，并进一步揭示Nmnat2在不同脑区对于脂代谢的调控作用和机制。研究发现不同形式节食后恢复饮食通常都会导致快速的肥胖，为揭示肥胖的机理开辟的新的研发方向，也为节食减脂提出了新的理论指导。合作绘制小鼠脂肪图谱，揭示不同部位脂肪的关键特征，为进一步了解不同部位脂肪的不同生物学功能打下了重要基础。