青钱柳三萜调控SIRT1/NF-κB信号通路干预肥胖2型糖尿病的效应及机制研究

Obese type 2 diabetic patients are challenged with weight gain, glucose variability and disorder of β-cell function in the pancreas, for which effective therapies and medicines are still lacking. Based on the traditional Chinese medicine theory, ‘damp’ and ‘heat’ are main pathological factors associated with obese type 2 diabetes. Modern medicine confirms that obesity-induced chronic inflammation is a key factor in the pathogenesis of obese type 2 diabetes. Cyclocarya paliurus is a traditional herb with Qingrejiedu (to clear heat and toxin) and Shengjinzhike (to help produce saliva and slake thirst) efficiency and it is reported to be of significant effects for the treatment of diabetes. Our previous findings revealed that Cyclocarya paliurus can inhibit inflammation-related insulin resistance and treat of obese type 2 diabetes. Triterpenoids might be its active components, which exert therapeutic effects through activation SIRT1. The important roles of SIRT1 in treatment of obesity-induced chronic inflammation has been confirmed. However, the mechanism that triterpenoids modulate this disease through SIRT1/NF-κB pathways remains unknown. In the present study, we will prepare a model system of adipose inflammation-related insulin resistance and establish the link between NF-κB and adipokines by focusing on the regulation of SIRT1 with possible methods such as siRNA technique, western blot analysis. Using these models as platforms, we will investigate the effect and mechanism of the triterpenoids from Cyclocarya paliurus on ameliorating obese type 2 diabetes. This study is conductive to provide new ideas and new ways for Chinese medicine in treatment of obesity type 2 diabetes.

肥胖2型糖尿病面临血糖波动、体重增加、胰岛β细胞功能紊乱等多重难题，目前临床上缺乏有效的治疗方法及药物。中医认为“阴津亏损、中满内热”为肥胖2型糖尿病主要病机，现代医学证实肥胖诱导的慢性炎症是其发病的关键因素。中草药青钱柳具有清热解毒，生津止渴的功效，对消渴症具有良好的治疗效果。本课题组前期研究证明青钱柳具有抑制炎性胰岛素抵抗，治疗肥胖2型糖尿病的效果。青钱柳三萜是其有效成分，并通过激活SIRT1发挥治疗作用。SIRT1在肥胖诱导的慢性炎症中作用已被证实，但是青钱柳三萜如何通过SIRT1调控炎症干预肥胖2型糖尿病的作用机理尚待研究。本项目拟以SIRT1活性作为切入点，在整体动物、细胞水平上建立炎性胰岛素抵抗模型体系，通过基因沉默、蛋白免疫印迹等技术，揭示青钱柳三萜通过调控SIRT1/NF-κB通路对肥胖2型糖尿病的干预效应及作用机理。本课题的实施为中医药治疗肥胖2型糖尿病提供新思路和新方法

糖尿病已成为继肿瘤、心血管疾病之后的第三大慢性非传染性疾病，其中90%以上为2型糖尿病。2型糖尿病面临血糖波动、体重增加、胰岛β细胞功能紊乱等多重难题，目前临床上仍缺乏有效的治疗方法及药物。中医认为“阴津亏损、中满内热”为2型糖尿病主要病机，现代医学证实肥胖诱导的慢性炎症是其发病的关键因素。中草药青钱柳具有清热解毒，生津止渴的功效，对糖尿病具有良好的治疗效果。本课题组前期研究发现青钱柳可显著抑制组织炎症，改善外周胰岛素抵抗，具有治疗2型糖尿病的潜力。此外，青钱柳三萜是主要有效成分，其药理活性与SIRT1靶点相关，但青钱柳三萜如何通过SIRT1调控慢性炎症干预2型糖尿病的作用机理尚待研究。本项目采用高脂饲料喂养C57BL/6J小鼠、Transwell共培养3T3-L1脂肪细胞及小鼠腹腔巨噬细胞RAW264.7，活化的巨噬细胞上清液诱导SIRT1-siRNA 重组腺病毒感染3T3-L1脂肪细胞，在整体动物、细胞及分子水平上构建炎性诱导的胰岛素抵抗模型体系，探究青钱柳三萜通过调控SIRT1/NF-κB通路对2型糖尿病的干预效应及作用机理。研究结果发现青钱柳三萜可以显著降低高脂饮食诱发的小鼠高血糖、内脏脂肪堆积及脂肪组织的炎症浸润，提高外周组织的胰岛素敏感性。此外，青钱柳三萜减少巨噬细胞向脂肪细胞的迁徙，并且降低细胞上清中炎症介质IL-6、TNFα、IL-1β、MCP-1的分泌及脂肪细胞中IKKβ、P65NF-κB的磷酸化水；SIRT1抑制剂EX-527干预后，细胞上清中炎症因子增加，IKKβ、P65NF-κB磷酸化水平增加。实验结果表明，青钱柳三萜可能对2型糖尿病具有一定治疗作用，其机制可能与SIRT1的激活有关。我们采用siRNA-SIRT1转染脂肪细胞，进一步考察青钱柳三萜药效，证实其干预脂肪组织慢性炎症及其胰岛素敏感性的药效具有SIRT1依赖性。本课题的实施为中医药治疗肥胖2型糖尿病提供新思路和新方法。本研究发表论文8篇，培养硕士研究生3名，完成预定目标。