2型糖尿病发病率持续升高,认知障碍是其常见并发症。栀子中环烯醚萜成分对糖尿病认知障碍有保护作用,抑制M1型小胶质细胞极化或为其机制但调控机理未知。线粒体裂变是M1型极化特征,抑制Drp1介导线粒体裂变可阻滞小胶质细胞M1型极化,炎性分子RIPK2可能是Drp1下游靶标且两者或有相互作用。Drp1的SUMO化修饰和RIPK2的泛素化修饰可能影响调控机制,且已预测修饰位点。前期研究筛选了环烯醚萜部位所含的活性成分,发现其能改善糖尿病认知障碍及神经炎症,下调M1型小胶质细胞极化及Drp1、RIPK2表达；分子对接预测与Drp1结合位点；Drp1和RIPK2呈共定位,免疫共沉淀发现两者有相互作用并预测其关键氨基酸位点。申请人推测栀子中环烯醚萜成分可能通过Drp1/RIPK2抑制M1型小胶质细胞极化而改善糖尿病认知障碍。本课题拟阐明栀子中环烯醚萜成分改善糖尿病认知障碍的机制,为药物研发提供新策略。

The morbidity of type 2 diabetes mellitus(T2DM) has been increasing in recent years, and cognitive impairment is the common complication. The Iridoids from Fructus Gardeniae exhibits protective effect on T2DM-associated cognitive impairment whereas its mechanism remains elusive. The suppression of M1 phenotype microglia polarization may be beneficial for the therapeutic effect of T2DM. Mitochondrial fission is the key feature of M1 phenotype. The inhibition of Drp1-mediated mitochondrial fission can prevent M1 phenotype microglia polarization. RIPK2 is a target for the regulation of inflammatory signaling. Drp1 may interact with RIPK2. The SUMOylation of Drp1 and ubiquitination of RIPK2 may influence the Iridoids from Fructus Gardeniae-mediated mechanism. The SUMOylation amino acid residue site and ubiquitination amino acid residue site were predicted. It is assumed that the suppression of Drp1/RIPK2 pathway is potential in the inhibition of M1 phenotype microglia polarization. Our previous experiments screened the active ingredients of Iridoids from Fructus Gardeniae, and found they attenuated the T2DM-associated cognitive impairment, inhibited M1 phenotype microglia polarization, downregulated the Drp1, RIPK2 expressions. The binding sites between active ingredients of Iridoids from Fructus Gardeniae and Drp1 were predicted by molecular docking. The colocalization of Drp1 and RIPK2 was observed by confocal laser scanning microscope. The interaction between Drp1 and RIPK2 was verified by Co-IP and its key amino acid residue site was predicted by protein docking and virtual saturation mutation. Therefore, it is speculated that Iridoids from Fructus Gardeniae ameliorates T2DM-associated cognitive impairment by inhibiting M1 phenotype microglia polarization through Drp1/RIPK2 pathway. The research will elucidate the mechanism of Iridoids from Fructus Gardeniae on T2DM-associated cognitive impairment and provide a new strategy for drug development.