靶向SGLT2是治疗糖尿病肾病（DN）的新策略，从海洋中寻找新型SGLT2抑制剂是一个新的研究方向，课题组前期研究发现海洋来源寡糖类小分子GL5可靶向结合SGLT2，具有显著的体外和体内抗DN作用，本课题综合运用蛋白定点突变、分子对接和动力学模拟、SPR、ITC、全细胞膜片钳、活细胞成像追踪等技术揭示GL5抑制SGLT2的动态作用过程，阐明GL5与SGLT2相互作用具体位点和结合区域；在此基础上采用shRNA、过表达、高内涵荧光分析等方法深入探讨GL5调控SphK1-S1P信号通路的分子机制及其与靶向SGLT2的内在联系。本项目的成功实施不仅可阐明GL5作为新型SGLT2抑制剂的动态作用模式，还有望揭示GL5调控SphK1-S1P信号通路抗DN的新颖作用机制，为抗DN海洋药物的理性设计提供新的分子模板，也为新一类结构骨架的SGLT2抑制剂抗DN研究与开发奠定理论基础。

An extensive body of researches have demonstrated the obvious advantages of SGLT2 inhibitors in the treatment of diabetic nephropathy (DN), and it's a new research area to find novel SLGT2 inhibitors from marine derived coumpounds. Our preliminary researches showed that the marine derived oligosaccharide GL5 could target for SGLT2 and exerted a potential anti-DN effects in vitro and in vivo. The present project intends to identify the binding sites and kinetic binding modes of GL5 to SGLT2 by using gene cloning, protein site mutation, combined with molecular docking and molecular dynamics simulations (Gromacs/Amber system), SPR(surface plasmon resonance), ITC(isothermal titration calorimetry), whole-cell patch clamp recording techniques; and to explore the effects of GL5 on the regulation of SphK1-S1P signaling pathways in the process of diabetic kidney disease and its interactions to the SGLT2 targeted inhibiton through several methods of shRNA, overexpression, high content imaging analysis, and so on. In summary, the project will not only provide a new molecular template for the rational design of anti-DN marine drugs, but also provide theoretical basis for the development and application of the new SGLT2 inhibitor in the treatment of diabetic kidney disease.