STK11对猪肌内脂肪沉积和糖脂代谢的影响及机制研究

Intramuscular fat (IMF), one of the key factors that determines the meat quality, is directly affected by the glucose and lipid metabolism. So to explore the effects of glucose and lipid metabolism key factors STK11 signaling on porcine IMF deposition and its regulation mechanism, is important for improving the meat quality and production of high quality of pork products. However, the role of porcine STK11 is not studied. Therefore, based on our previous studies, the current project will establish a fluorescence activated cell sorting (FACS) technique for separation and purification the porcine IMF stem cells , and then to explore the biological characteristics of the IMF stem cells. In addition, the correlation between STK11 expression and IMF deposition in pigs will be studied. Furthermore, from molecular level, cellular level and whole animal level, the role and the regulation network of STK11 on IMF stem cells’ glycolipid metabolism, differentiation, and IMF deposition will be determined by using tissue-specific STK11 knockout mouse model combined with the CRISPR / cas9 gene knockout, gene overexpression, immunofluorescence co-localization, immunoprecipitation and omics technologies etc.. Through our study, we want to reveal the specific regulatory mechanism of the IMF deposition, and to provide theoretical basis for further increase the IMF content and produce high quality pork products by nutrition regulation technology without affecting the leanness. Meanwhile, our studies will provide important reference for the study of human glucose and lipid metabolic disorders related diseases. Publish 3-5 academic papers.

肌内脂肪（IMF）是影响肉质的关键因素，糖脂代谢直接影响着IMF 沉积。因此，探究糖脂代谢关键因子STK11对猪IMF沉积的影响及机制，对改善我国猪肉品质和生产优质猪肉具有非常重要的意义。但目前关于猪STK11的研究还鲜见报道。因此，本项目在前期研究的基础上，首先建立猪IMF干细胞FACS分离纯化技术并探讨其生物学特性；解析STK11与猪IMF沉积的关系，并进一步利用CRISPR/Cas9基因敲除、超表达、免疫荧光、免疫共沉淀、组学等生物学技术，结合组织特异性STK11敲除鼠模型，从分子、细胞和动物整体水平探讨STK11对IMF干细胞分化、糖脂代谢和IMF沉积的影响及调控网络。通过本项目研究，为揭示IMF特异性沉积的调控机制，并通过营养手段在不影响瘦肉率的前提下适当提高IMF含量和生产优质猪肉产品奠定理论基础；同时为人类糖脂代谢紊乱相关代谢性疾病的研究提供重要借鉴。发表学术论文3-5篇。

肌内脂肪（IMF）沉积是影响猪肉品质的关键因素，如何调控IMF含量是改善猪肉品质的关键科学问题之一。STK11（又叫LKB1）可直接调控AMPK激酶活性，是动物糖脂代谢的关键调控因子，但关于STK11对猪脂肪沉积特别是IMF沉积的影响还未见报道。本研究主要探究了STK11对IMF分化聚酯的影响及调控机制。建立了猪、小鼠的IMF干细胞体外培养模型，初步阐明了IMF分化聚酯等细胞生物学特性，解析了STK11表达与IMF沉积的关系，并构建了STK11的RNA干扰（RNAi）、CRISPR-Cas9-sgRNA以及超表达载体及相关病毒，通过RNA-Seq等技术探究了STK11对猪IMF分化及糖脂代谢的影响及分子机理。发现STK11除通过经典的AMPK通路外，还可通过RNA m6A甲基化、MAPK、PPAR等相关信号通路调控IMF分化和脂质代谢。在此基础上，进一步构建了高IMF沉积模型和STK11脂肪细胞特异性敲除动物模型，探究了脂肪细胞特异性敲除STK11对肌内脂肪沉积和皮下脂肪和的影响；发现脂肪细胞特异性敲除STK11可以显著促进GLY诱导的肌IMF沉积，并可以通过mTOR信号通路调控皮下脂肪沉积。相关研究结果为通过靶向STK11基因表达调控脂肪沉积提供了一定的理论基础。