新型褪黑素受体激动剂Neu-P11改善胰岛素敏感性的研究

Neu-P11, a novel melatonin receptor agonist, has been confirmed its effect on sleep promotion. Research findings show that there is a close relationship between insulin resistance(IR), Type 2 Diabetes Mellitus(T2DM) and sleep disorders.In addition, our previous results showed that Neu-P11 inhibits increasing of body weight and decreases the level of plasm glucose,which proved the regulation effect of Neu-P11 on energy metabolism. Therefore, we hypothesize that Neu-P11 may influence the insulin sensitivity. The study will be carried out in the following two aspects: ① On the basis of the successfully-built IR models in animals and adipocytes, effect of Neu-P11 on the insulin sensitivity will be researched both in vivo and vitro in order to confirm the hypotheses of this project, and hyperinsulinemic euglycemic clamp and isotope-labeled glucose transport method will be applied; ②At the same time,the research content includes analyzing the morphous and primary phase insulin secretion of islets isolated from the animal subjects; the expression of IRS-1(Ser307),GSK-3(Ser21) as well as molecules in the insulin IRS-1/PI3-K/Akt signal pathway; expression and membrane translocation of GLUT4 in IR-adipocytes. The results will illuminate the potential mechanism by which Neu-P11 improves the insulin sensitivity, and the link betweem signal pathways of insulin and melatonin. The study will make us know more about Neu-P11 apart from its effect on sleep, and will provide a theory basis for its application to the prevention and treatment of metabolism syndroma such as IR, T2DM and sleep disorder; Furthermore, the study will help uncover the underlying relationship between insulin/β Cell of islet and melatonin/pineal gland, which will offer original targets for the treatment of IR, T2DM.

新型的褪黑素受体激动剂Neu-P11具有改善睡眠的作用。研究表明睡眠障碍与胰岛素抵抗（IR）的发生联系密切；我们前期研究证实Neu-P11能抑制体重增长、降低血浆糖脂水平，提示Neu-P11可能通过改善胰岛素敏感性发挥作用。本项目拟①采用胰岛素钳夹和葡萄糖转运实验，观察Neu-P11对IR的3T3-L1脂肪细胞和大鼠模型胰岛素敏感性的影响；②采用免疫组化法观察胰岛的形态结构、放免法分析离体胰岛第一相胰岛素分泌、Western blot分析IRS-1/PI3-K/Akt通路及IRS-1(Ser307)、GSK-3(Ser21)、GLUT4的表达以及采用激光共聚焦分析GLUT4的易位，阐明Neu-P11调节胰岛素敏感性的机制及胰岛素信号通路与褪黑素受体后途经的交叉点。研究将明确Neu-P11对胰岛素信号传导的影响；揭示褪黑素和胰岛素/胰岛β细胞的关系，为探索IR、2型糖尿病的治疗提供新的靶点。

本项目基于睡眠紊乱和胰岛素抵抗的密切关系，首次把把治疗睡眠障碍的药物Neu-P11(Piromelatine)应用于代谢紊乱的治疗研究。采用高糖高脂膳食喂养构建胰岛素抵抗（IR）的SD大鼠模型、通过睡眠限制诱导SD大鼠发生代谢紊乱、采用FFA或高糖高胰岛素共孵育诱导诱导建立3T3-L1脂肪细胞IR模型，通过检测模型动物或细胞对葡萄糖的摄取、TG的蓄积等评价Neu-P11对胰岛素敏感性的影响，并对其机制进行了研究。研究结果显示：1）Neu-P11能改善膳食诱导肥胖大鼠和睡眠限制大鼠的代谢紊乱、改善其胰岛素敏感性；降低肥胖大鼠体重的增长和腹部脂肪的蓄积；2）Neu-P11能促进3T3-L1 IR细胞对胰岛素介导的葡萄糖摄取，同时上调Akt、GLUT-4的表达并降低IRS-1Ser307的磷酸化；3）Neu-p11显著降低IR脂肪细胞内TG含量，上调该脂肪细胞中ATGL、HSL蛋白的表达；4）Neu-P11明显逆转HGI引起的高ROS水平、升高IR细胞线粒体膜电位、抑制JNK/ NF-κBp65蛋白的活性。以上结果提示Neu-P11对胰岛素敏感性的调节与其调节胰岛素信号通路关键分子的表达、改善细胞氧化应激状态等作用有密切关系。因此，本项目已基本完成了研究内容，发表了一系列研究论文，其中SCI收录5篇，申报了3项专利，获得省自然科学奖三等奖1项、市科技进步奖二等奖1项，培养毕业了两名硕士研究生，实现了预期目标。