基于自噬对Keap1-Nrf2通路的调控探索姜黄素抗抑郁作用的分子机制

Depression is a high-incidence and harmful disease, which causes significant losses to the society. Curcumin is an active ingredient extracted from traditional Chinese medicine turmeric. Clinical studies have confirmed that curcumin is safe and effective in the treatment of depression, but the mechanism underlying is still not fully understood. In recent years, studies have found that some antidepressants work by activating autophagy, and curcumin is a natural autophagy activator. Autophagy could activate Keap1-Nrf2 signaling pathway through p62 to produce anti-oxidative stress and anti-apoptosis effect. In previous experiments, we observed that the autophagy was disordered in an animal model of depression. Furthermore, we found that curcumin showed antidepressant-like effect, and curcumin could activate nuclear transcription of Nrf2 and alleviate oxidative stress damage in nerve cells. Based on the results and literature review, we hypothesized that curcumin could induce autophagy to activate the Keap1-Nrf2 pathway to produce antidepressant effects. To validate the hypothesis, both cellular and animal experiments will be carried out using interventions such as autophagy inhibitors 3-MA and Nrf2 knockout mice. The methods will be used including behavioral tests, Western-blot techniques, confocal analysis, immunohistochemistry, and Tunel staining. The aim of this study was to explore the neuroactivity of curcumin and provide new ideas for the treatment of depression.

抑郁症发病率高，病理机制复杂。近期研究表明自噬同抑郁症密切相关，我们也发现抑郁模型脑内伴随着自噬的紊乱，而部分抗抑郁药物需要通过激活自噬起作用。姜黄素是中药姜黄的活性成分，具有安全性好和多靶点作用的特点，临床和基础研究均表明其有一定的抗抑郁作用。本课题组前期动物实验也证实姜黄素有抗抑郁样作用，同时发现姜黄素能够激活Nrf2核转录，减轻神经细胞氧化应激损伤。鉴于自噬可通过p62途径激活Keap1-Nrf2信号通路，且姜黄素是一种天然的自噬激活剂，本研究拟探讨姜黄素经由自噬激活Keap1-Nrf2通路产生抗抑郁作用这一重要分子机制。本项目拟从细胞和动物实验两方面进行验证，使用自噬抑制剂3-MA及Nrf2基因敲除鼠等干预，采用行为学检测、Western-blot技术、共聚焦分析、免疫组化、Tunel染色等研究手段，以期进一步挖掘姜黄素的神经活性，并为抑郁症的治疗提供新的思路。

姜黄素(Curcumin, CUR)是中药姜黄的活性成分，临床和基础研究均表明其有一定的抗抑郁作用。然而，其抗抑郁的机制仍未完全阐明。在本项目的支持下，我们发现CUR不仅有效抑制皮质酮（CORT）建立的抑郁模型小鼠的抑郁样行为，还能改善伴随的焦虑样行为和认知功能减退。随后，分子生物学研究显示，姜黄素可显著增加抑郁模型组海马NIX、Beclin-1、PINK1、Parkin和LC3II/LC3I水平等自噬相关蛋白水平，提高NRF1、TFAM和MT-CO1/SDH-A比值等线粒体生物合成标志物水平，以及提高Nrf2、NQO-1、HO-1、GCLC、SOD-1等抗氧化应激损伤标志物的水平。同时，CUR治疗后抑郁模型小鼠海马通过透射电镜观察到线粒体形态的恢复、使用DHE染色观察到细胞氧化应激损伤的减轻，以及Nissl染色观察到神经元丢失减少。体外培育小鼠原代海马神经元细胞，CUR明显拮抗了CORT诱导的神经元细胞PGC-1α、Nrf2蛋白水平，NQO-1、SOD-1、HO-1、GCLC基因表达水平，以及MT-CO1/SDH-A比值下降，和体内研究结果类似。同时，CUR可纠正CORT引起的线粒体免疫荧光信号在神经元细胞核周围聚集、恢复CORT阻碍的mt-Keima标记自噬流信号、降低CORT引起的MitoSox标记氧化应激损伤信号、以及改善CORT导致的凋亡损伤。最后，无论是体内还是体外，使用PGC-1α抑制剂SR18292可以阻断以上CUR的保护作用。本研究验证了线粒体自噬和Nrf2介导的抗氧化应激通路在姜黄素抗抑郁药理活性中起重要作用，并进一步明确上游PGC-1α是二者调控的关键，为姜黄素治疗抑郁症打下坚实的药理学理论基础。