Recent efforts to model human diseases in vivo in Drosophila

Upon completion of sequencing the Drosophila genome, it was estimated that 61% of human disease-associated genes had sequence homologs in flies, and in some diseases such as cancer, the number was as high as 68%. We now know that as many as 75% of the genes associated with genetic disease have counterparts in Drosophila. Using better tools for mutation detection, association studies and whole genome analysis the number of human genes associated with genetic disease is steadily increasing. These detection efforts are outpacing the ability to assign function and understand the underlying cause of the disease at the molecular level. Drosophila models can therefore advance human disease research in a number of ways by: establishing the normal role of these gene products during development, elucidating the mechanism underlying disease pathology, and even identifying candidate therapeutic agents for the treatment of human disease. At the 49(th) Annual Drosophila Research Conference in San Diego this year, a number of labs presented their exciting findings on Drosophila models of human disease in both platform presentations and poster sessions. Here we can only briefly review some of these developments, and we apologize that we do not have the time or space to review all of the findings presented which use Drosophila to understand human disease etiology.     

Recent efforts to model human diseases in vivo in Drosophila

Upon completion of sequencing the Drosophila genome, it was estimated that 61% of human disease-associated genes had sequence homologs in flies, and in some diseases such as cancer, the number was as high as 68%1. We now know that as many as 75% of the genes associated with genetic disease have counterparts in Drosophila.2 Using better tools for mutation detection, association studies and whole genome analysis the number of human genes associated with genetic disease is steadily increasing. These detection efforts are outpacing the ability to assign function and understand the underlying cause of the disease at the molecular level. Drosophila models can therefore advance human disease research in a number of ways by: establishing the normal role of these gene products during development, elucidating the mechanism underlying disease pathology, and even identifying candidate therapeutic agents for the treatment of human disease.

At the 49th Annual Drosophila Research Conference in San Diego this year, a number of labs presented their exciting findings on Drosophila models of human disease in both platform presentations and poster sessions. Here we can only briefly review some of these developments, and we apologize that we do not have the time or space to review all of the findings presented which use Drosophila to understand human disease etiology.     

Drosophila as a screening tool to study human neurodegenerative diseases

In an aging society, research involving neurodegenerative disorders is of paramount importance. Over the past few years, research on Alzheimer's and Parkinson's diseases has made tremendous progress. Experimental studies, however, rely mostly on transgenic animal models, preferentially using mice. Although experiments on mice have enormous advantages, they also have some inherent limitations, some of which can be overcome by the use of Drosophila melanogaster as an experimental animal. Among the major advantages of using the fly is its small genome, which can also be modified very easily. The fact that its genome lends itself to diverse alterations (e. g. mutagenesis, transposons) has made the fly a useful organism to perform large‐scale and genome‐wide screening approaches. This has opened up an entirely new field of experimental research aiming to elucidate genetic interactions and screen for modifiers of disease processes in vivo. Here, we provide a brief overview of how flies can be used to analyze molecular mechanisms underlying human neurodegenerative diseases.     

Recent advances in sunlight-induced carcinogenesis using the Xiphophorus melanoma model

Unlike breast and prostate cancers, the nature and sequence of critical genetic and epigenetic events involved in the initiation and progression of melanoma are not well understood. A contributing factor to this dilemma, especially given our current understanding of the importance of UV light in melanoma etiology, is the lack of quality UV-inducible melanoma animal models. In this study we elaborate on the capability of UV light to induce cutaneous malignant melanomas (CMM) in Xiphophorus fishes, which were previously found to develop melanomas after acute neonatal UVB irradiation. In two separate tumorigenesis experiments, we exposed adult Xiphophorus hybrids to either acute UVB irradiations (5 consecutive daily treatments) or chronic solar irradiations (continuous UVA/UVB treatment for 9 months). Acute adult UVB irradiation resulted in the significant induction of melanomas, and moreover, this induction rate is equivalent to that of animals exposed to acute neonatal UVB irradiation. This study represents the first evidence that acute adult UVB irradiation, in the absence of any early life exposures, induces CMM. Similar to the findings conducted on other divergent melanoma models, including HGF/SF transgenic mice and Monodelphis domestica, prolonged chronic solar UV was not a factor in melanomagenesis.     

Autophagy deregulation in neurodegenerative diseases - recent advances and future perspectives

Autophagy is an evolutionarily conserved homeostatic process for the turnover of cellular contents, organelles and misfolded proteins through the lysosomal machinery. Recently, the involvement of autophagy in the pathophysiology of neurodegenerative diseases has attracted considerable interest because autophagy deregulation has been linked to some of these neurodegenerative disorders. This interest is further heightened by the demonstration that various autophagic pathways, including macroautophagy and chaperone-mediated autophagy, are implicated in the turnover of proteins that are prone to aggregation in cellular or animal disease models. These observations have stimulated new awareness in the pivotal role of the autophagic pathways in neurodegenerative disease pathophysiology, and have sparked extensive research aimed at deciphering the mechanisms by which autophagy is altered in these disorders. Here, we summarize the latest advances in our understanding of the role of autophagy deregulation in Parkinson's, Alzheimer's and Huntington's disease.     

Recent advances in imaging embryonic myoblast fusion in Drosophila

Myoblast fusion in the Drosophila embryos is a complex process that includes changes in cell movement, morphology and behavior over time. The advent of fluorescent proteins (FPs) has made it possible to track and image live cells, to capture the process of myoblast fusion, and to carry out quantitative analysis of myoblasts in real time. By tagging proteins with FPs, it is also possible to monitor the subcellular events that accompany the fusion process. Herein, we discuss the recent progress that has been made in imaging myoblast fusion in Drosophila, reagents that are now available, and microscopy conditions to consider. Using an Actin-FP fusion protein along with a membrane marker to outline the cells, we show the dynamic formation and breakdown of F-actin foci at sites of fusion. We also describe the methods used successfully to show that these foci are primarily if not wholly present in the fusion-competent myoblasts.     

The neuroinflammatory biomarker YKL-40 for neurodegenerative diseases: advances in development

Introduction: Neuroinflammation is a common pathophysiological mechanism in neurodegenerative diseases (ND). Cerebrospinal fluid (CSF) YKL-40 has recently been candidated as a neuroinflammatory biomarker of ND.

Areas covered: We provide an update on the role of CSF YKL-40 as a pathophysiological biomarker of ND. YKL-40 may discriminate Alzheimer’s disease (AD) from controls and may predict the progression from the early preclinical to the late dementia stage. In genetic AD, YKL-40 increases decades before the clinical onset. It does not seem a specific biomarker of a certain ND although sporadic Creutzfeldt–Jacob disease shows the highest YKL-40 concentrations. YKL-40 may discriminate between amyotrophic lateral sclerosis (ALS) and ALS-mimics. YKL-40 is potentially associated with the rate of ALS progression. YKL-40 correlates with biomarkers of neuronal injury, large axonal damage and synaptic disruption in various ND. It is not associated with the presence of the APOE-ε4 allele whereas possibly linked to aging, female sex, Hispanic ethnicity and some genetic variants of the chitinase-3-like 1 locus.

Expert opinion: There is growing evidence expanding the relevance of CSF YKL-40 as a pathophysiological biomarker for ND. Patients showing high YKL-40 levels might benefit from targeted clinical trials that use compounds acting against neuroinflammatory mechanisms, independently of the initial clinical diagnosis of ND.     

应用荧光分析法检测酶的研究进展

酶是细胞新陈代谢的基础,酶的检测在生物技术、疾病诊断及药物开发等领域都具有十分重要的意义。在检测酶的诸多方法中,荧光法因其灵敏度高、检测限低等优势发展迅速。以下简述了近年来荧光法在酶检测领域的研究,根据检测方法的不同分为直接荧光检测法和间接荧光检测法,其中直接检测法又根据不同的底物标记及检测机理进行分类。以下介绍了各种方法的应用,并展望了此类方法的前景和发展趋势,为酶工程及生命科学其他领域的相关研究提供信息。     

Modeling human neurodegenerative diseases in Drosophila: on a wing and a prayer

The ability of Drosophila genetics to reveal new insights into human neurodegenerative disease is highlighted not only by mutants in flies that show neuronal cell loss, but also by targeted expression of human disease genes in the fly. Moreover, study of Drosophila homologs of various human disease genes provides new insight into fundamental aspects of protein function. These recent findings confirm the remarkable homology of gene function in flies when compared with humans. With the advent of complete genomic sequencing on the horizon, Drosophila will continue to be an outstanding model system in which to unravel the complexities, causes and treatments for human neural degeneration.     

Understanding human diseases using Drosophila

One of the major goals of biomedical research is to elucidate the causal relationships of critical factors involved in the initiation and progression of human diseases at the molecular and cellular levels. This knowledge is required for developing effective treatments for major diseases including cancer, cardiovascular and metabolic diseases, as well as neurodegenerative diseases and neurological disorders. Because of their phylogenetic representations and relative ease of experimental manipulation, model organisms such as the budding yeast (Saccharomyces cerevisiae), the nematode worm (Caenorhabditis elegans), the fruit fly (Drosophila melanogaster'), the thale cress (Arabidopsis thaliana), the zebrafish (Danio rerio'), the frog (Xenopus laevis), and the mouse (Mus musculus}, have been extensively studied over the past century (Hedges, 2002;Muller and Grossniklaus, 2010;Dietrich et al., 2014).     

Functional genomics approaches to neurodegenerative diseases

Many of the neurodegenerative diseases that afflict humans are characterised by the protein aggregation in neurons. These include complex diseases like Alzheimer’s disease and Parkinson’s disease, and Mendelian diseases caused by polyglutamine expansion mutations [like Huntington’s disease (HD) and various spinocerebellar ataxias (SCAs), like SCA3]. A range of functional genomic strategies have been used to try to elucidate pathways involved in these diseases. In this minireview, I focus on how modifier screens in organisms from yeast to mice may be of value in helping to elucidate pathogenic pathways.     

Oligodendrocytes in neurodegenerative diseases

Oligodendrocyte is a highly specialized glial cell type in the vertebrate central nervous system, which guarantees the long-distance transmission of action potential by producing myelin sheath wrapping adjacent axons. Disrupted myelin and oligodendrocytes are hallmarks of some devastating neurological diseases, such as multiple sclerosis, although their contribution to neurodegeneration in a given disease is still controversial. However, accumulating evidence from clinical studies and genetic animal models implicates oligodendrocyte dysfunction as one of major events in the processes of initiation and progression of neurodegeneration. In this article, we will review recent progress in understanding non-traditional function of oligodendrocytes in neuronal support and protection independent of myelin sheath and its possible contribution to neurodegeneration. Oligodendrocytes play a pivotal role in neurodegenerative diseases among which special emphasis is given to multiple system atrophy and Alzheimer’s disease in this review.     

Proteomics in neurodegenerative diseases

The effects of amyloid-beta (Aβ) protein on the expression of m1, m2 subunits of mAChR and on α7nAChR were analyzed in the cerebral cortex and in the hippocampus of rats following injections of Aβ (1–40) (BACHEM, 2 μg in 1 μL of PBS) into the left retroesplenial cortex (RSg) and injections of 1 μL of PBS into the right RSg. Sections were immunoreacted for the localization of α7, m1, m2, GABA, somatostatin and parvalbumin. Injections of Aβ resulted in loss of neurones expressing α7- and m1-like immunoreactivity (IR) in frontal, RSg cortices, hippocampus and subicular complex. A decrease of α7, m1- and m2-like-IR fibers and structures-like terminals was also seen in hippocampus, subicular and cerebral cortex. α7nAChR and m1, m2 subuntis of mAChRs were most commonly identified on GABAergic interneurones. These results point to an effect of Aβ on the synthesis of α7nAChR and mAChRs and suggest an important role of cholinoceptive interneurones in the dysfunction of hippocampus and cerebral cortex seen in AD.     

宏基因组测序在传染性疾病中的研究进展

微生物和人类已经共同进化几百万年了,微生物在维持宿主健康方面起到了非常重要的作用。随着下一代测序技术的进步,可以获得人体在不同环境下微生物群落的特征。本文综述了当前感染各种不同病原菌时复杂微生物群落的变化,病原菌包括HIV、乙肝病毒、流感病毒和结核分支杆菌,以及不同的身体部位。我们相信,增加对传染性疾病和微生物群落变化之间关系的认识,能够更好地管理疾病进展。然而,将来的研究可能需要更加整体化,通过分析人体宿主微生物与传染性疾病的发生机制之间的关系,以建立疾病的确切因果关系。     

利钠肽家族基因与心血管疾病研究新进展

利钠肽家族是一组由心肌细胞分泌的激素, 主要包括A型、B型和C型利钠肽, 具有相似的基因结构和生理学效应, 可对心血管系统产生血压调节、抗心肌肥厚、抗心肌纤维化和抗心肌弛缓等保护作用。利钠肽受体A、B和C亦介导多种生理活性, 调节心血管稳态。利钠肽受体A选择性结合A型、B型利钠肽。利钠肽受体B结合C型利钠肽。利钠肽受体C结合各型利钠肽, 通过受体介导的内化和退化作用清除血液循环中利钠肽。对利钠肽家族及其受体基因单核甘酸多态性及功能研究显示, 其与多种心血管疾病(房颤、高血压、心力衰竭等)的易感性相关。利钠肽家族及其受体基因缺失的转基因小鼠表现为心肌肥厚、心肌纤维化, 与高血压、心肌病及心力衰竭的发生发展相关。各种导致心肌肥厚和缺血性损伤的刺激均参与利钠肽及其受体基因的表达调控。临床将脑钠肽作为左室功能障碍和心力衰竭失代偿的一个预测指标。静脉注射重组脑钠肽已经成为治疗急性心力衰竭的有效手段。深入了解利钠肽家族基因变异及其信号调控有助于探索心血管疾病的病理生理机制, 为临床诊疗开辟新思路。