治疗阿尔茨海默病的多肽的药效学研究
发布时间：2019-05-20 03:18
【摘要】：阿尔茨海默病(Alzheimer’s disease, AD)是一种以老年人记忆和认知功能损伤为临床表征的神经退行性疾病。AD是老年痴呆疾病中最常见的形式，病理特征包括A聚集形成的老年斑(senile plaques, SP)、Tau蛋白异常磷酸化形成的神经纤维缠结(neurofibrillary tangles, NFT)、神经元丢失导致的脑萎缩、胶质增生以及炎症。在AD的发病过程中，Aβ扮演着重要的角色。Aβ是新陈代谢的自然产物，由39-42个氨基酸组成，由β-分泌酶(BACE1)和γ-分泌酶水解加工淀粉样前体蛋白(APP)产生。大量的研究表明，Aβ的聚集在AD的发病机制中发挥关键性作用。Aβ单体聚集形成的可溶性的寡聚体是引发神经细胞毒性的主要原因，而氧化应激与炎症反应是其诱发细胞毒性的主要机制。 到目前为止，尽管不能确定AD的发生是否伴随氧化应激反应，但是，氧化应激反应在AD的病程进展中发挥着重要的作用。氧化应激过程中Aβ聚集物能够诱导活性氧(Reactive oxygen species, ROS)的过度产生。产生的ROS可能损伤包括蛋白、脂质以及DNA在内的多种类型的生物大分子。虽然脂质过氧化反应产生的丙二醛(MDA)具有神经毒性，尤其是可能导致蛋白质变性，影响蛋白质功能，但是脂质过氧化本身可以通过直接损伤细胞膜结构的完整性导致细胞凋亡甚至死亡。另一方面，据报道，在AD病人的脑中，对ROS具有解毒作用的内源性的抗氧化物酶的水平降低。其中超氧化物歧化酶(SOD)与谷胱甘肽过氧化物酶(GSH-Px)是最主要的抗氧化物酶，能够抵抗自由基诱导的氧化性损伤，发挥细胞保护作用。此外，Aβ聚集物能够激活小胶质细胞，促进前炎症细胞因子诸如肿瘤坏死因子α(TNF-α)和白介素1β(IL-1β)的释放，进而促进下游炎症级联反应的发生。因此，在AD的修饰型药物研发过程中，降低Aβ42聚集引起的神经毒性、抑制Aβ42诱导产生的氧化应激以及前炎症细胞因子的释放成为治疗与预防AD的可行性计策。 在先前的研究工作中，实验室以Aβ单体为靶分子，利用噬菌体展示技术，从环型七肽库中经过三轮筛选、富集、洗脱得到了能够特异性与Aβ结合的多肽，并命名为XD3。本文在原来研究的基础上，对XD3在体内以及体外水平的药效学进行了研究。 在细胞水平研究结果表明，多肽XD3能够抑制Aβ42诱导产生的神经细胞毒性；通过减少活性氧(ROS)以及氧化型谷胱甘肽(GSSG)的生成，，增加还原型谷胱甘肽GSH的含量，增强SOD、GSH-Px的活性降低Aβ42诱导产生的氧化应激反应；此外，XD3可以下调Aβ42诱导的促炎症细胞因子TNF-α和IL-1β的释放。 同时，应用XD3对AD转基因小鼠的治疗结果表明，XD3可以明显改善小鼠的认知记忆功能、通过降低脑内的胶质细胞增生抑制炎症反应、降低脑内老年斑的沉积以及氧化应激等病理性变化。 XD3作为小分子多肽，具有靶点明确、治疗作用明显、副作用小以及制备方便的特性，为AD的治疗提供了具有良好应用前景的免疫制剂。
[Abstract]:Alzheimer's disease (Alzheimer's disease, AD) is a neurodegenerative disease characterized by memory and cognitive impairment in the elderly. Ad is the most common form of Alzheimer's disease. The pathological features included brain atrophy, glial hyperplasia and inflammation caused by the loss of (neurofibrillary tangles, NFT), neurons in neurofibrillar tangles caused by abnormal phosphorylation of (senile plaques, SP), Tau protein in elderly plaques. A 尾 plays an important role in the pathogenesis of AD. A 尾 is a natural product of metabolism, which is composed of 39 amino acids and is produced by hydrolysis of 尾-secretase (BACE1) and gamma-secretase to process starch precursor protein (APP). A large number of studies have shown that the aggregation of A 尾 plays a key role in the pathogenesis of AD. The soluble oligomer formed by A 尾 monomer aggregation is the main cause of neurocytotoxicity. Oxidative stress and inflammation are the main mechanisms of cytotoxicity. Up to now, although it is impossible to determine whether the occurrence of AD is accompanied by oxidative stress, oxidative stress plays an important role in the course of AD. During oxidative stress, A 尾 aggregates can induce the overproduction of reactive oxygen species (Reactive oxygen species, ROS). The resulting ROS may damage many types of biological macromolecules, including proteins, lipids and DNA. Although malondialdehyde (MDA) (MDA) produced by lipid peroxide is neurotoxic, especially it may lead to protein denaturation and affect protein function. However, lipid peroxide itself can directly damage the integrity of cell membrane structure leading to apoptosis and even death. On the other hand, it is reported that the level of endogenous antioxidant enzymes that detoxify ROS is reported to be decreased in the brains of AD patients. Among them, (SOD) and GSH-Px are the most important antioxidant enzymes, which can resist oxidative damage induced by free radicals and play a role in cell protection. In addition, A 尾 aggregates can activate microglia and promote the release of proinflammatory cytokines such as tumor necrosis factor 伪 (TNF- 伪) and IL 1 尾 (IL-1 尾), thus promoting the occurrence of downstream inflammatory cascade reaction. Therefore, in the process of modified drug development of AD, reducing the neurotoxicity caused by A 尾 42 aggregation, inhibiting the oxidative stress induced by A 尾 42 and the release of proinflammatory cytokines are the feasible strategies for the treatment and prevention of AD. In the previous research work, using A 尾 monomer as the target molecule and bacteriophage display technique, the polypeptide which can specifically bind to A 尾 was obtained by three rounds of screening and eluting from the cyclic seven peptide library, and named XD3.. On the basis of the original study, the pharmacokinetics of XD3 in vivo and in vitro was studied. The results showed that polypeptide XD3 could inhibit the neurotoxicity induced by A 尾 42. By reducing the production of reactive oxygen species (ROS) and oxidized glutathione (GSSG), the content of reduced glutathione GSH was increased, and the activity of SOD,GSH-Px was enhanced to decrease the oxidative stress induced by A 尾 42. In addition, XD3 could down-regulate the release of pro-inflammatory cytokines TNF- 伪 and IL-1 尾 induced by A 尾 42. At the same time, the treatment of AD transgenic mice with XD3 showed that XD3 could significantly improve the cognitive memory function of mice and inhibit inflammatory response by reducing the proliferation of glial cells in the brain. Reduce the deposition of aging plaques in the brain and oxidative stress and other pathological changes. As a small molecular polypeptide, XD3 has the characteristics of clear target, obvious therapeutic effect, small side effects and convenient preparation, which provides an immune preparation with good application prospect for the treatment of AD.
【学位授予单位】：安徽农业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R749.16;R96
本文编号：2481301
[Abstract]:Alzheimer's disease (Alzheimer's disease, AD) is a neurodegenerative disease characterized by memory and cognitive impairment in the elderly. Ad is the most common form of Alzheimer's disease. The pathological features included brain atrophy, glial hyperplasia and inflammation caused by the loss of (neurofibrillary tangles, NFT), neurons in neurofibrillar tangles caused by abnormal phosphorylation of (senile plaques, SP), Tau protein in elderly plaques. A 尾 plays an important role in the pathogenesis of AD. A 尾 is a natural product of metabolism, which is composed of 39 amino acids and is produced by hydrolysis of 尾-secretase (BACE1) and gamma-secretase to process starch precursor protein (APP). A large number of studies have shown that the aggregation of A 尾 plays a key role in the pathogenesis of AD. The soluble oligomer formed by A 尾 monomer aggregation is the main cause of neurocytotoxicity. Oxidative stress and inflammation are the main mechanisms of cytotoxicity. Up to now, although it is impossible to determine whether the occurrence of AD is accompanied by oxidative stress, oxidative stress plays an important role in the course of AD. During oxidative stress, A 尾 aggregates can induce the overproduction of reactive oxygen species (Reactive oxygen species, ROS). The resulting ROS may damage many types of biological macromolecules, including proteins, lipids and DNA. Although malondialdehyde (MDA) (MDA) produced by lipid peroxide is neurotoxic, especially it may lead to protein denaturation and affect protein function. However, lipid peroxide itself can directly damage the integrity of cell membrane structure leading to apoptosis and even death. On the other hand, it is reported that the level of endogenous antioxidant enzymes that detoxify ROS is reported to be decreased in the brains of AD patients. Among them, (SOD) and GSH-Px are the most important antioxidant enzymes, which can resist oxidative damage induced by free radicals and play a role in cell protection. In addition, A 尾 aggregates can activate microglia and promote the release of proinflammatory cytokines such as tumor necrosis factor 伪 (TNF- 伪) and IL 1 尾 (IL-1 尾), thus promoting the occurrence of downstream inflammatory cascade reaction. Therefore, in the process of modified drug development of AD, reducing the neurotoxicity caused by A 尾 42 aggregation, inhibiting the oxidative stress induced by A 尾 42 and the release of proinflammatory cytokines are the feasible strategies for the treatment and prevention of AD. In the previous research work, using A 尾 monomer as the target molecule and bacteriophage display technique, the polypeptide which can specifically bind to A 尾 was obtained by three rounds of screening and eluting from the cyclic seven peptide library, and named XD3.. On the basis of the original study, the pharmacokinetics of XD3 in vivo and in vitro was studied. The results showed that polypeptide XD3 could inhibit the neurotoxicity induced by A 尾 42. By reducing the production of reactive oxygen species (ROS) and oxidized glutathione (GSSG), the content of reduced glutathione GSH was increased, and the activity of SOD,GSH-Px was enhanced to decrease the oxidative stress induced by A 尾 42. In addition, XD3 could down-regulate the release of pro-inflammatory cytokines TNF- 伪 and IL-1 尾 induced by A 尾 42. At the same time, the treatment of AD transgenic mice with XD3 showed that XD3 could significantly improve the cognitive memory function of mice and inhibit inflammatory response by reducing the proliferation of glial cells in the brain. Reduce the deposition of aging plaques in the brain and oxidative stress and other pathological changes. As a small molecular polypeptide, XD3 has the characteristics of clear target, obvious therapeutic effect, small side effects and convenient preparation, which provides an immune preparation with good application prospect for the treatment of AD.
【学位授予单位】：安徽农业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R749.16;R96
【参考文献】
相关期刊论文 前1条
1 庄莹;陈杰;;阿尔茨海默病病因及发病机制研究进展[J];吉林医药学院学报;2008年02期
本文编号：2481301
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