小分子化合物对PC12细胞氧化性损伤的保护作用及其机制的探究

发布时间：2018-03-18 23:21

本文选题：氧化应激　切入点：神经退行性疾病　出处：《兰州大学》2017年博士论文　论文类型：学位论文

【摘要】：大脑是人体神经系统的高级中枢区域,它控制着人的感觉、记忆、情绪、运动以及逻辑思维等,俨然已经是人体的“中央处理器”。然而随着人类年龄不断地增长以及周遭环境日益的变化,与大脑有关的疾病也不断地侵袭而来,比如阿尔兹海默症、帕金森症、肌肉萎缩症、抑郁症以及精神分裂症等,这些疾病严重影响着病患的生活质量乃至威胁到生命,而随着人类平均年龄的增长,患此类疾病的概率也随之增加。因此,研究这些疾病的发病机制,并且寻找有效地治疗方案是极其重要的。当细胞内氧化还原平衡被打破,即产生活性氧的能力超越消除活性氧的能力时,细胞内很容易发生氧化应激,而氧化应激会引发很多疾病,所以机体都会尽量维持细胞内氧化还原平衡。由于大脑内含有大量不饱和脂肪酸,所以很容易受到活性氧的攻击。当大脑部位的活性氧过多,而内源性抗氧化系统过度疲劳时,会引发多种神经退行性疾病。因此,维持大脑内部的氧化还原平衡对于预防神经退行性疾病是尤为重要的。转录因子Nrf2是细胞内源性抗氧化系统非常重要的组成部分,当细胞内出现氧化应激或被亲电试剂进攻时,Nrf2能够逃脱它的抑制剂Keap1介导的泛素化-降解的过程,并转位到细胞核。在细胞核中,Nrf2作为转录因子,它会结合Maf蛋白,进而增加抗氧化应答元件(ARE)的转录,最终激活一系列细胞保护分子,比如血红素加氧酶-1(HO-1),NAD(P)H:醌氧化还原酶1(NQO1),硫氧还蛋白还原酶(TrxR),硫氧还蛋白(Trx)和谷胱甘肽(GSH)等,所有的这些分子都能够调节细胞内氧化还原平衡。因此,发展Nrf2的激活剂是非常重要的,并且可以形成靶向治疗神经退行性疾病的新疗法。一般含有酚羟基和或迈克尔加成受体的天然小化合物可能会具有抗氧化和保护细胞的性质。在本文中,我们的目标是筛选或合成一些具有类似基团的化合物,检测其神经保护作用,并探索作用机制,为发展基于体内氧化还原调节体系为靶点的神经保护药物提供实验和理论数据。本论文的内容总结归纳如下:1.对Keap1-Nrf2-ARE信号通路进行了概述,也对Keap1-Nrf2-ARE和神经退行性疾病之间的关系做了简介,同时,我也对此通路的调节方式进行了总结。2.从日常饮食和中草药中筛选并发现五种化合物,包括羟基酪醇(HT)、姜烯酚(6-S)、小豆蔻明(CD)、芒果苷(Mg)和木香烃内酯(COS),实验表明这五种化合物均对过氧化氢(H2O2)或6-羟基多巴胺(6-OHDA)诱导的PC12细胞损伤有很好的抵御作用。机理研究表明这五种化合物可以激活PC12细胞内的Nrf2,使Nrf2发生核转位,进而促进一系列Nrf2驱动的抗氧化分子,如HO-1,NQO1,GSH,Trx和TrxR。此外,通过shRNA转染沉默PC12细胞中Nrf2的表达,可以消除或削弱这些化合物的保护作用,说明激活Nrf2是这五个化合物在PC12细胞中保护作用的主要分子机制。3.设计、合成Hispolon以及其五个类似物,并评价了它们对PC12细胞的神经保护作用。通过一系列生物实验,我们筛选了两种化合物(H1和H6)用于后续研究。该课题表明,这两种化合物均有神经保护作用,而且可以激活PC12细胞中转录因子Nrf2,这为发展神经保护药物提供了很好的途径。
[Abstract]:The brain is a senior central region of human nervous system, which controls people's feeling, memory, emotion, movement and logical thinking, has become the body's "central processor". However, with the change of human age increasing and the environment increasingly, associated with brain diseases are constantly invasion, for example, Alzheimer's disease, Parkinson's disease, muscular dystrophy, depression and schizophrenia, these diseases seriously affect the patient's quality of life and even threaten life, with the average age of human growth, the probability of disease is also increased. Therefore, the pathogenesis of these diseases, and to find effective treatment plan is extremely important. When the intracellular redox balance is broken, the production of reactive oxygen species beyond the ability to eliminate ROS, intracellular oxidative stress occurs easily However, oxidative stress may induce many diseases, so the body will try to maintain the intracellular redox balance. Because the brain contains large amounts of unsaturated fatty acids, so it is vulnerable to ROS attack. When ROS brain excessive, excessive fatigue and endogenous antioxidant system, will lead to a variety of neural diseases degeneration. Therefore, to maintain the oxidation reduction equilibrium inside the brain is particularly important for the prevention of neurodegenerative diseases. The transcription factor Nrf2 is a very important part of the endogenous antioxidant system, when intracellular oxidative stress or by electrophilic attack, Nrf2 inhibitors can escape its Keap1 mediated ubiquitination - degradation, and translocate to the nucleus. In the nucleus, Nrf2 as a transcription factor, it will bind to the Maf protein, thus increasing the antioxidant response element (ARE) transcription, the final activation of a series of Column cell protective molecules, such as heme oxygenase -1 (HO-1), NAD (P) H: quinone oxidoreductase 1 (NQO1), thioredoxin reductase (TrxR), thioredoxin (Trx) and glutathione (GSH) and so on, all of these molecules can regulate the intracellular redox balance. Therefore, the development of Nrf2 activator is very important, and can form a new targeted therapy for the treatment of neurodegenerative diseases. Generally contain natural compounds or small phenolic hydroxyl and Michael addition receptors may have antioxidant and protective properties. In this paper, our goal is to screening or synthetic compounds have some similar groups, detect its neuroprotective effect, and to explore the mechanism, for the development of in vivo redox regulation system to provide theoretical and experimental data for the neuroprotective drugs target. Based on the contents of total nodes are summarized as follows: 1. to Keap1-Nrf2-AR The E signaling pathway are reviewed, also on the relationship between Keap1-Nrf2-ARE and neurodegenerative diseases were briefly introduced, at the same time, I also have access regulation are summarized from the.2. diet and Chinese herbal medicine screening and found five compounds, including hydroxytyrosol (HT), Jiang Xifen (6-S), cardamom Ming (CD), mangiferin (Mg) and costunolide (COS), the experiment shows that the five compounds are on hydrogen peroxide (H2O2) or 6- 6-hydroxydopamine (6-OHDA) induced PC12 cell injury has good effect against. Mechanism research showed that these five compounds can activate PC12 cells within the Nrf2. The Nrf2 nuclear translocation, and promote a series of antioxidant molecules, Nrf2 driver such as HO-1, NQO1, GSH, Trx and TrxR. in Nrf2 expression by transfection of shRNA silencing in PC12 cells, which can eliminate or weaken the protective effect of these compounds, suggest that the activation of Nrf2 is five The main molecular mechanism of protective effect of compounds in PC12 cells in.3. design, synthesis of Hispolon and its analogues, and evaluate their neuroprotective effects on PC12 cells. Through a series of biological experiments, we screened two compounds (H1 and H6) for the following research. The project shows that the two the compound have neuroprotective effect, but also can activate the transcription factor Nrf2 in PC12 cells, which provides a good way for the development of neuroprotective drugs.

【学位授予单位】：兰州大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R91

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