基于生物钟基因Cry探讨姜黄素干预慢性应激大鼠胰岛素抵抗的分子机制

On the basis of our previous study that curcumin could improve the depression and insulin resistance, this proposal is designed to explore the molecular mechanisms of curcumin in the treatment of depression combined with insulin resistance based on the regulation of circadian clock genes. Cryptochrome (Cry) is a key regulatory gene of circadian clock, and it regulates circadian rhythm through negative feedback mechanisms. Abnormal expression of Cry can lead to circadian rhythm disorders. Recently, Cry was found to have a close relationship with depression and T2D. This work is planned to build a rat model of depression combined with insulin resistance using chronic stress as stimulating factors. Firstly, we investigate the key roles of abnormal expression of Cry in liver in the pathogenesis of depression combined with insulin resistance. Secondly, to elucidate the molecular mechanisms improving insulin resistance in chronic stress rats, we evaluate the effects of curcumin on Cry expression in liver, and explore the upstream regulation mechanisms. This research will provide a new direction for the development of therapeutic drugs in treatment of depression combined with insulin resistance.

在前期研究发现姜黄素具有抗抑郁和改善胰岛素抵抗作用的基础上，本课题从调节生物钟基因的角度探讨姜黄素干预抑郁症并发胰岛素抵抗的分子机制。隐花色素（Cry）是一种生物钟关键调控基因，通过负反馈机制调节生物体昼夜节律变化。Cry的异常表达可导致生理节律的紊乱。最近研究发现，Cry与抑郁症和糖尿病密切相关。本课题以慢性应激模拟人类抑郁症的环境诱因，建立抑郁合并胰岛素抵抗大鼠模型；以肝脏Cry为切入点，探讨生物钟基因异常表达在抑郁症并发胰岛素抵抗病理机制中的关键作用；以姜黄素为研究对象，系统评价姜黄素对慢性应激大鼠肝脏Cry的调节作用，并探讨其上游调控机制，阐明姜黄素通过调节生物钟基因以改善慢性应激大鼠胰岛素抵抗的分子机制。本课题将从调节生物钟基因的角度为开发抑郁并发胰岛素抵抗的治疗药物提供新思路。

本研究基于慢性温和刺激（CMS）模型，对CMS诱导的胰岛素抵抗和生物钟紊乱，及姜黄素的干预作用进行了相关研究，发现：（1）CMS可显著损伤胰岛素敏感性，促进肝糖异生，加速脂肪组织和肝糖原分解，扰乱血糖和血脂水平；（2） CMS可引起肝脏生物钟基因表达紊乱，Cry1、Cry2、Bmal1和Clock的mRNA表达均显著减少，同时减少Cry2的蛋白表达，增加Cry1的蛋白表达；（3）姜黄素可显著逆转胰岛素抵抗，增加糖原含量并改善血糖血脂水平，同时显著上调Cry1和Cry2的表达，逆转生物钟基因的表达紊乱；（4） 姜黄素激活LKB1/AMPK，提高AKT磷酸化表达，抑制GSK3b的表达，促进糖原合成并抑制葡萄糖异生。上述结果初步证实了我们提出的生物钟基因Cry参与了CMS诱导的胰岛素抵抗机制，提示了姜黄素可能基于调节生物钟基因紊乱以改善胰岛素抵抗的作用机制，这些研究结果有助于揭示姜黄素的药理作用机制，为其临床应用提供理论依据，但仍存在诸多问题需要进一步解决。