果蝇模型在研究铁代谢相关神经退行性疾病发病机制中的应用(英文)

铁代谢紊乱一直被视为是许多神经退行性疾病共同的病理特征,如阿尔茨海默氏症(Alzheimer’s disease,AD)、帕金森氏病(Parkinson’s disease,PD)以及弗里德赖希共济失调(Friedreich’s ataxia,FRDA)等均与脑铁代谢紊乱密切相关。随着分子生物学的进展,迄今为止也已经发现许多参与铁运输、储存和调控的基因与神经退行性病变的发生和发展有关,然而铁代谢紊乱在疾病发病过程中的致病机制仍不十分清楚。近年来许多研究者利用各种转基因动物模型来研究铁代谢相关神经退行性疾病的发病机制,但是啮齿类动物模型由于模型构建系统周期较长且比较复杂,从而限制了铁相关蛋白在神经退行性疾病中作用机制的研究进展。果蝇具有生活周期短暂、染色体数目少以及表型易于观察等优点,同时果蝇与人在很多基因和通路上都高度保守,且神经系统也可表现出与人相似的复杂的功能,因此被广泛地应用在铁代谢相关神经退行性疾病发病机制的研究中。果蝇还以其独特的分子遗传学优势,更容易构建缺失、插入、敲除或转基因模型,可在不同神经退行性病理情况下进行遗传学筛选铁相关的调控基因,从而为解决铁代谢紊乱在疾病发病过程中的致病机制提供更多的线索。因此在果蝇模型中发现可以中止甚至是逆转神经元退化进程的铁相关基因,以期为神经退行性疾病的研究和治疗提供策略。     

生命科学与人类疾病研究的重要模型——果蝇

黑腹果蝇(Drosophilamelanogaster)是生物学研究中最重要的模式生物之一,它在遗传的染色体理论建立中起到非常重要的作用。由于果蝇自身独特的优势,20世纪70年代以来,它又在发育生物学、神经科学、人类疾病研究等领域得到广泛应用,作出许多新的重要贡献。果蝇在神经退行性疾病研究中是非常有用的模型。可以预期,随着研究手段的丰富及科学的发展,果蝇将作为一种理想的模式生物在生物医学中发挥更大的作用。     

利用帕金森症的果蝇模型测试具有神经保护作用的化学活性分子(英文)

帕金森症的果蝇模型对解析疾病的分子细胞机制贡献极大.为探讨利用地中海黑腹果蝇的疾病模型来筛选新型治疗帕金森症药物的可能性,我们构建了基于DJ-1A和PINK1两个遗传致病因子的帕金森症果蝇模型,测试抗氧化和消炎活性分子米诺环素和辅酶Q10对脑多巴胺浓度的影响.结果表明,米诺环素对DJ-1A果蝇模型有明显保护作用,能显著提高脑多巴胺的浓度,但是对PINK1果蝇模型没有保护作用;辅酶Q10对两种模型均有保护作用.因此,帕金森病的果蝇模型能够反映药物分子的特异性作用,为筛选新的帕金森病治疗药物提供了一条便捷的途径.     

转基因果蝇模型与多聚谷氨酰胺疾病

多聚谷氨酰胺(polyglutamine,PolyQ)疾病是由CAG三核苷酸异常重复扩增并编码多聚谷氨酰胺链而致病的一类疾病.目前,已经发现了9种PolyQ疾病,临床表现为成年起病,缓慢进展性的神经系统功能障碍.近年来许多研究者用转基因动物模型(小鼠、果蝇、斑马鱼等)研究神经退行性疾病的表型、发病机制及治疗,其中,果蝇以其独特的分子遗传学优势成为研究PolyQ疾病的理想模式生物.本文就运用转基因果蝇研究PolyQ疾病的表型及发病机制作一综述.     

神经退行性疾病的表观遗传学

研究发现多种疾病的发生与表观遗传学相关.有证据显示表观遗传学信号在大脑中起着重要调节作用,在哺乳动物中枢神经系统中DNA甲基化动力学被发现是表观遗传学调节的主要组成,染色质修饰药物的快速发展显示出对神经系统中范围广泛的退行性功能紊乱出人意料的治疗作用,促进了人们对神经退行性疾病的表观遗传学机制研究.其中,研究得比较多的是DNA甲基化、组蛋白修饰及染色质重塑.这些研究为神经退行性疾病的治疗提供了潜在靶点,并为开发相关药物提供了线索.对疾病表观遗传学机制及药物的作用机制的进一步研究将为疾病治疗提供更多靶点,为神经退行性疾病提供确切的有效治疗途径,具有积极意义.     

利用黑腹果蝇（Drosophila melanogaster）研究微量金属元素代谢

微量金属参与了生物体许多化学反应过程,同时也可作为蛋白质的辅基或辅因子起作用,对机体生长发育以及正常生物功能的维持具有重要作用;微量金属元素的代谢失衡与生物体许多疾病密切相关,如威尔森氏病、门克斯病、铁色素沉积、肠变性皮炎以及一些神经退行性疾病。黑腹果蝇（Drosophila melanogaster）是遗传背景清楚、生活周期短、操作方便的模式生物,利用果蝇研究金属离子代谢以及金属离子代谢与疾病的联系具有独特的优势,近年来,随着果蝇基因组测序的完成以及许多转基因果蝇株的建立,果蝇也越来越多的用于金属离子代谢的研究。介绍了近年来果蝇在金属离子代谢研究领域的进展,以及其与神经退行性疾病关系研究上的一些应用。     

果蝇在肿瘤学研究中的优势及应用前景

果蝇作为研究人类疾病的模式生物, 与哺乳动物不仅在基本的生物学、生理学和神经系统机能等方面比较相似, 而且果蝇有其作为模式生物的独特优势。近年来的研究表明, 果蝇和人类在肿瘤发生信号通路等方面的保守性很高, 而且果蝇具有很强的遗传学可操作性, 是肿瘤学研究有效的模型之一, 可用于研究人类肿瘤发生、发展、转移等分子机制。文章综述了果蝇在肿瘤学研究中的优势、已建立的用于研究特定癌症的果蝇模型, 并对其在未来肿瘤学的研究方向进行展望, 以期为国内肿瘤学研究和抗肿瘤药物的研发提供参考。     

果蝇热激蛋白的研究进展

热休克蛋白(heat shock proteins,HSPs)是生物体受到应激刺激时诱导产生的一组保守性蛋白,普遍存在于各种生物体中。近年来,果蝇Drosophila作为生命科学与人类疾病研究的重要模式生物,其热激蛋白的研究取得了许多新的进展。文章对果蝇热激蛋白的类别、热激蛋白基因的表达调控机制、热激蛋白的分子伴侣功能、调节细胞存亡和影响发育及寿命等相关生物学功能进行综述,并对热激蛋白在神经退行性疾病治疗中的应用前景作展望。     

老年性阿兹海默症发病机制与其果蝇模型

衰老机理的研究是揭示衰老的本质和防治老年性疾病的一个重要环节,同时也为抗衰老提供理论依据.诸多研究表明,阿兹海默症（Alzheimer’s disease,AD）等神经退行性疾病与衰老密切相关.在老年性AD病研究中,果蝇是一种通常被用于研究其发病机理与治疗方法的重要模型.本文就AD病的发病机制、与衰老相关通路的联系、以及果蝇模型在AD病中的研究进展进行了综述.为研究老年性AD病的机理和治疗提供参考.     

单分子生物物理技术在神经递质释放研究中的应用

神经递质的释放在神经信号传导中起着至关重要的作用.神经递质释放严格依赖SNARE蛋白的动态组装和钙离子触发的膜融合过程.最新研究发现,神经递质释放还受到神经退行性疾病中关键的标志蛋白分子的影响.当前研究者以体外膜融合重组体系为基础,发展了多种单分子生物物理技术,为进一步阐明神经递质释放的分子机制和神经退行性疾病的发病机理提供了新的视角和手段.     

Neurodegenerative mutants in Drosophila: a means to identify genes and mechanisms involved in human diseases?

There are 50 ways to leave your lover (Simon 1987) but many more to kill your brain cells. Several neurodegenerative diseases in humans, like Alzheimer’s disease, have been intensely studied but the underlying cellular and molecular mechanisms are still unknown for most of them. For those syndromes where associated gene products have been identified their biochemistry and physiological as well as pathogenic function is often still under debate. This is in part due to the inherent limitations of genetic analyses in humans and other mammals and therefore experimentally accessible invertebrate in vivo models, such as Caenorhabditis elegans and Drosophila melanogaster, have recently been introduced to investigate neurodegenerative syndromes. Several laboratories have used transgenic approaches in Drosophila to study the human genes associated with neurodegenerative diseases. This has added substantially to our understanding of the mechanisms leading to neurodegenerative diseases in humans. The isolation and characterization of Drosophila mutants, which display a variety of neurodegenerative phenotypes, also provide valuable insights into genes, pathways, and mechanisms causing neurodegeneration. So far only about two dozen such mutants have been described but already their characterization reveals an involvement of various cellular functions in neurodegeneration, ranging from preventing oxidative stress to RNA editing. Some of the isolated genes can already be associated with human neurodegenerative diseases and hopefully the isolation and characterization of more of these mutants, together with an analysis of homologous genes in vertebrate models, will provide insights into the genetic and molecular basis of human neurodegenerative diseases.     

Recent advances in using Drosophila to model neurodegenerative diseases

Neurodegenerative diseases are progressive disorders of the nervous system that affect the function and maintenance of specific neuronal populations. Most disease cases are sporadic with no known cause. The identification of genes associated with familial cases of these diseases has enabled the development of animal models to study disease mechanisms. The model organism Drosophila has been successfully used to study pathogenic mechanisms of a wide range of neurodegenerative diseases. Recent genetic studies in the Drosophila models have provided new insights into disease mechanisms, emphasizing the roles played by mitochondrial dynamics, RNA (including miRNA) function, protein translation, and synaptic plasticity and differentiation. It is anticipated that Drosophila models will further our understanding of mechanisms of neurodegeneration and facilitate the development of novel and rational treatments for these debilitating neurodegenerative diseases.     

Insights into ALS pathomechanisms: from flies to humans

Amyotrophic Lateral Sclerosis (ALS) is a devastating neurodegenerative disease causing the death of motor neurons with consequent muscle atrophy and paralysis. Several neurodegenerative diseases have been modeled in Drosophila and genetic studies on this model organism led to the elucidation of crucial aspects of disease mechanisms. ALS, however, has lagged somewhat behind possibly because of the lack of a suitable genetic model. We were the first to develop a fly model for ALS and over the last few years, we have implemented and used this model for a large scale, unbiased modifier screen. We also report an extensive bioinformatic analysis of the genetic modifiers and we show that most of them are associated in a network of interacting genes controlling known as well as novel cellular processes involved in ALS pathogenesis. A similar analysis for the human homologues of the Drosophila modifiers and the validation of a subset of them in human tissues confirm and expand the significance of the data for the human disease. Finally, we analyze a possible application of the model in the process of therapeutic discovery in ALS and we discuss the importance of novel “non-obvious” models for the disease.     

Can flies help humans treat neurodegenerative diseases?

Neurodegenerative diseases are becoming increasingly common as life expectancy increases. Recent years have seen tremendous progress in the identification of genes that cause these diseases. While mutations have been found and cellular processes defined that are altered in the disease state, the identification of treatments and cures has proven more elusive. The process of finding drugs and therapies to treat human diseases can be slow, expensive and frustrating. Can model organisms such as Drosophila speed the process of finding cures and treatments for human neurodegenerative diseases? We pose three questions, (1) can one mimic the essential features of human diseases in an organism like Drosophila, (2) can one cure a model organisms of human disease and (3) will these efforts accelerate the identification of useful therapies for testing in mice and ultimately humans? Here we focus on the use of Drosophila to identify potential treatments for neurodegenerative diseases such as Huntington's and we discuss how well these therapies translate into mammalian systems. BioEssays 26:485–496, 2004. © 2004 Wiley Periodicals, Inc.     

lats基因在细胞周期和肿瘤发生中的作用

lats基因(large tumor suppressor gene)最早在果蝇中发现,在小鼠和人中均有同源基因.该基因的功能从果蝇到人是高度保守的.lats基因的功能包括:作为肿瘤抑制基因,其突变会导致肿瘤的发生;磷酸化的Lats与Cdc2结合,参与细胞周期的调控;通过细胞-细胞间的通讯,可能参与生物体个体大小的调控机制.从果蝇到人lats基因功能的研究,提供了以果蝇作为模式生物研究哺乳动物基因功能的方法.     

<Emphasis Type="Italic">Drosophila</Emphasis> retinophilin contains MORN repeats and is conserved in humans

The function of conserved novel human genes can be efficiently addressed in genetic model organisms. From a collection of genes expressed in the Drosophila visual system, cDNAs expressed in vertebrates were identified and one similar to a novel human gene was chosen for further investigation. The results reported here characterize the Drosophila retinophilin gene and demonstrate that a similar gene is expressed in the human retina. The Drosophila and human retinophilin sequences are 50% identical, and they share an additional 16% conserved substitutions. Examination of the cDNA and genomic sequence indicates that it corresponds to the gene CG10233 of the annotated genome and predicts a 22.7 kDa protein. Polyclonal antibodies generated to a predicted retinophilin peptide recognize an antigen in Drosophila photoreceptor cells. The retinophilins encode 4 copies of a repeat associated with a Membrane Occupation and Recognition Nexus (MORN) function first discovered in junctophilins, which may interact with the plasma membrane. These results therefore show that Drosophila retinophilin is expressed in fly photoreceptor cells, demonstrate that a conserved human gene is expressed in human retina, and suggest that a mutational analysis of the Drosophila gene would be valuable.     

Insights into ALS pathomechanisms: from flies to humans

Amyotrophic Lateral Sclerosis (ALS) is a devastating neurodegenerative disease causing the death of motor neurons with consequent muscle atrophy and paralysis. Several neurodegenerative diseases have been modeled in Drosophila and genetic studies on this model organism led to the elucidation of crucial aspects of disease mechanisms. ALS, however, has lagged somewhat behind possibly because of the lack of a suitable genetic model. We were the first to develop a fly model for ALS and over the last few years, we have implemented and used this model for a large scale, unbiased modifier screen. We also report an extensive bioinformatic analysis of the genetic modifiers and we show that most of them are associated in a network of interacting genes controlling known as well as novel cellular processes involved in ALS pathogenesis. A similar analysis for the human homologues of the Drosophila modifiers and the validation of a subset of them in human tissues confirm and expand the significance of the data for the human disease. Finally, we analyze a possible application of the model in the process of therapeutic discovery in ALS and we discuss the importance of novel “non-obvious” models for the disease.     

Study of tauopathies by comparing <Emphasis Type="Italic">Drosophila</Emphasis> and human <Emphasis Type="Italic">tau</Emphasis> in <Emphasis Type="Italic">Drosophila</Emphasis>

The microtubule-binding protein tau has been investigated for its contribution to various neurodegenerative disorders. However, the findings from transgenic studies, using the same tau transgene, vary widely among different laboratories. Here, we have investigated the potential mechanisms underlying tauopathies by comparing Drosophila (d-tau) and human (h-tau) tau in a Drosophila model. Overexpression of a single copy of either tau isoform in the retina results in a similar rough eye phenotype. However, co-expression of Par-1 with d-tau leads to lethality, whereas co-expression of Par-1 with h-tau has little effect on the rough eye phenotype. We have found analogous results by comparing larval proteomes. Through genetic screening and proteomic analysis, we have identified some important potential modifiers and tau-associated proteins. These results suggest that the two tau genes differ significantly. This comparison between species-specific isoforms may help to clarify whether the homologous tau genes are conserved. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. This study was supported by the National Science Foundation of China (30270341; 30630028), the Multidisciplinary Program (Brain and Mind) of the Chinese Academy of Sciences, the Major State Basic Research Program (“973 program”; G2000077800; G2006CB806600; 2006CB911003), the Precedent Project of Important Intersectional Disciplines in the Knowledge Innovation Engineering of the Chinese Academy of Sciences (KJCX1-09-03).     

The cholesterol trafficking protein NPC1 is required for Drosophila spermatogenesis

Niemann–Pick C (NPC) disease is a lethal neurodegenerative disorder affecting cellular sterol trafficking. Besides neurodegeneration, NPC patients also exhibit other pleiotropic conditions, indicating that NPC protein is required for other physiological processes. Previous studies indicated that a sterol shortage that in turn leads to a shortage of steroid hormones (for example, ecdysone in Drosophila) is likely to be the cause of NPC disease pathology. We have shown that mutations in Drosophila npc1, one of the two NPC disease-related genes, leads to larval lethal and male infertility. Here, we reported that npc1 mutants are defective in spermatogenesis and in particular in the membrane-remodeling individualization process. Interestingly, we found that ecdysone, the steroid hormone responsible for the larval lethal phenotype in npc1 mutants, is not required for individualization. However, supplying 7-dehydrocholesterol can partially rescue the male infertility of npc1 mutants, suggesting that a sterol shortage is responsible for the spermatogenesis defects. In addition, the individualization defects of npc1 mutants were enhanced at high temperature, suggesting that the sterol shortage may lead to temperature-sensitive defects in the membrane-remodeling process. Together, our study reveals a sterol-dependent, ecdysone-independent mechanism of NPC1 function in Drosophila spermatogenesis.