A survey of human disease gene counterparts in the Drosophila genome

Morpholine Anchored Fluorogenic Toolkit: Unveiled Disease Allied Protein Fibrillation in Lysosomal Compartment of Live-Cell and Drosophila Models

The aberrant accumulation of cytotoxic protein aggregates is a hallmark of various neurodegenerative and non-neurodegenerative ailments, necessitating the development of sensitive and selective tools for their detection. Herein, we report a series of morpholine-anchored fluorescent probes, denoted as SC-nmor (n = 2, 4, 6), designed for facile visualization of protein aggregates. These probes display notable changes in their photophysical properties upon binding with protein aggregates, owing to their high sensitivity to the fibrillar microenvironment. Specifically, the SC-4mor probe demonstrates strong selectivity for aggregated insulin proteins over native insulin, accompanied by a significant enhancement in fluorescence lifetime. Live-cell imaging reveals an exclusive localization at the lysosomal compartment. This feature enables the visualization of lysosomal accumulated protein fibrils induced with pepstatin A. Additionally, in vivo assessments on genetically mutated and dietary-modified Drosophila melanogaster, representing neurodegenerative and non-neurodegenerative disease models, demonstrate staining of protein aggregates. The enhanced emission from the eye lobes of Aβ-mutated and HSD brain samples, suggesting that SC-4mor can exhibit adequate retention in the brain with minimal biological toxicity. SC-4mor also shows its capability to cross the blood-brain barrier in mice model. Consequently, SC-4mor emerges as a promising marker for detecting and monitoring neurotoxic protein fibrillation in live cells and animal models, offering potential insights into the pathogenesis and progression of protein aggregation.

High-throughput, low-cost FLASH: irradiation of Drosophila melanogaster with low-energy X-rays using time structures spanning conventional and ultrahigh dose rates

FLASH radiotherapy is an emerging technique in radiation oncology that may improve clinical outcomes by reducing normal tissue toxicities. The physical radiation characteristics needed to induce the radiobiological benefits of FLASH are still an active area of investigation. To determine the dose rate, range of doses and delivery time structure necessary to trigger the FLASH effect, Drosophila melanogaster were exposed to ultrahigh dose rate (UHDR) or conventional radiotherapy dose rate (CONV) 120-kVp X-rays. A conventional X-ray tube outfitted with a shutter system was used to deliver 17- to 44-Gy doses to third-instar D. melanogaster larvae at both UHDR (210 Gy/s) and CONV (0.2-0.4 Gy/s) dose rates. The larvae were then tracked through development to adulthood and scored for eclosion and lifespan. Larvae exposed to UHDR eclosed at higher rates and had longer median survival as adults compared to those treated with CONV at the same doses. Eclosion rates at 24 Gy were 68% higher for the UHDR group (P < 0.05). Median survival from 22 Gy was >22 days for UHDR and 17 days for CONV (P < 0.01). Two normal tissue-sparing effects were observed for D. melanogaster irradiated with UHDR 120-kVp X-rays. The effects appeared only at intermediate doses and may be useful in establishing the dose range over which the benefits of FLASH can be obtained. This work also demonstrates the usefulness of a high-throughput fruit fly model and a low-cost X-ray tube system for radiobiological FLASH research.

Drosophila as a Model for Human Disease: Insights into Rare and Ultra-Rare Diseases

Rare and ultra-rare diseases constitute a significant medical challenge due to their low prevalence and the limited understanding of their origin and underlying mechanisms. These disorders often exhibit phenotypic diversity and molecular complexity that represent a challenge to biomedical research. There are more than 6000 different rare diseases that affect nearly 300 million people worldwide. However, the prevalence of each rare disease is low, and in consequence, the biomedical resources dedicated to each rare disease are limited and insufficient to effectively achieve progress in the research. The use of animal models to investigate the mechanisms underlying pathogenesis has become an invaluable tool. Among the animal models commonly used in research, Drosophila melanogaster has emerged as an efficient and reliable experimental model for investigating a wide range of genetic disorders, and to develop therapeutic strategies for rare and ultra-rare diseases. It offers several advantages as a research model including short life cycle, ease of laboratory maintenance, rapid life cycle, and fully sequenced genome that make it highly suitable for studying genetic disorders. Additionally, there is a high degree of genetic conservation from Drosophila melanogaster to humans, which allows the extrapolation of findings at the molecular and cellular levels. Here, I examine the role of Drosophila melanogaster as a model for studying rare and ultra-rare diseases and highlight its significant contributions and potential to biomedical research. High-throughput next-generation sequencing (NGS) technologies, such as whole-exome sequencing and whole-genome sequencing (WGS), are providing massive amounts of information on the genomic modifications present in rare diseases and common complex traits. The sequencing of exomes or genomes of individuals affected by rare diseases has enabled human geneticists to identify rare variants and identify potential loci associated with novel gene-disease relationships. Despite these advances, the average rare disease patient still experiences significant delay until receiving a diagnosis. Furthermore, the vast majority (95%) of patients with rare conditions lack effective treatment or a cure. This scenario is enhanced by frequent misdiagnoses leading to inadequate support. In consequence, there is an urgent need to develop model organisms to explore the molecular mechanisms underlying these diseases and to establish the genetic origin of these maladies. The aim of this review is to discuss the advantages and limitations of Drosophila melanogaster, hereafter referred as Drosophila, as an experimental model for biomedical research, and the applications to study human disease. The main question to address is whether Drosophila is a valid research model to study human disease, and in particular, rare and ultra-rare diseases.

Transgenic Drosophila Expressing Active Human LH Receptor in the Gonads Exhibit a Decreased Fecundity: Towards a Platform to Identify New Orally Active Modulators of Gonadotropin Receptor Activity

BACKGROUND/OBJECTIVES

The gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH) and their receptors are major regulators of reproduction in mammals and are absent in insects. We previously established transgenic Drosophila lines expressing a constitutively active human LH receptor variant (LHRD578Y) and the wild-type receptor (LHRwt; inactive in the absence of an agonist). That study showed that ubiquitously expression of LHRD578Y-but not of LHRwt-resulted in pupal lethality, and targeted expression in midline cells resulted in thorax/bristles defects. To further study the Drosophila model for an in vivo drug screening platform, we investigated here whether expressing LHRD578Y in the fly gonads alters reproduction, as shown in a transgenic mice model.

METHODS

The receptor was expressed in somatic cells of the gonads using the tissue-specific traffic jam-Gal4 driver. Western blot analysis confirmed receptor expression in the ovaries.

RESULTS

A fecundity assay indicated that the ectopic expression of LHRD578Y resulted in a decrease in egg laying compared to control flies carrying, but not expressing the transgene (~40% decrease in two independent fly lines, p < 0.001). No significant reduction in the number of laid eggs was seen in flies expressing the LHRWT (<10% decrease compared to non-driven flies, p > 0.05). The decreased egg laying demonstrates a phenotype of the active receptor in the fly gonads, the prime target organs of the gonadotropins in mammals. We suggest that this versatile Drosophila model can be used for the pharmacological search for gonadotropin modulators.

CONCLUSIONS

This is expected to provide: (a) new mimetic drug candidates (receptor-agonists/signaling-activators) for assisted reproduction treatment, (b) blockers for potential fertility regulation, and (c) leads relevant for the purpose of managing extra gonadotropic reported activities.

Simple model systems reveal conserved mechanisms of Alzheimer's disease and related tauopathies

The lack of effective therapies that slow the progression of Alzheimer's disease (AD) and related tauopathies highlights the need for a more comprehensive understanding of the fundamental cellular mechanisms underlying these diseases. Model organisms, including yeast, worms, and flies, provide simple systems with which to investigate the mechanisms of disease. The evolutionary conservation of cellular pathways regulating proteostasis and stress response in these organisms facilitates the study of genetic factors that contribute to, or protect against, neurodegeneration. Here, we review genetic modifiers of neurodegeneration and related cellular pathways identified in the budding yeast Saccharomyces cerevisiae, the nematode Caenorhabditis elegans, and the fruit fly Drosophila melanogaster, focusing on models of AD and related tauopathies. We further address the potential of simple model systems to better understand the fundamental mechanisms that lead to AD and other neurodegenerative disorders.

On body-environment continuities from a laboratory commensalism

The article attends to everyday practices in a laboratory of neural genetics that studies olfaction, with the fruit fly as its model organism. Practices in neural genetics exhibit one of the 'post' aspects in post-genomic science - a turn to the environment. To get at how laboratory members engage body-environment continuities, I pay attention to an occasion of designing experimental chambers for an optogenetics study. As practitioners deal with the body's continuities with the world by engaging the spatial character of olfaction, their accounts exhibit qualities of feelings of immediate experience, relatable to C.S. Peirce's phenomenological category of Firstness. While these traces of Firstness inevitably manifest themselves in mixtures with the other two of Peirce's categories - namely, Secondness and Thirdness - noticing them allows for an engagement of the environment that goes beyond action and meaning. I reflect on that environment by considering the involvement of scientists' bodies in life with flies, while not forgetting my inhabitation of the laboratory space. Rather than relying on a cross-mapping of attributes known from the human sphere (intentional states or features of the human body) while managing a measurable space observed from the outside, this is an environment lived from within and with others. I conclude the article by proposing its noticing as an orientation toward ecological preoccupations.

Toxicities of amyloid-beta and tau protein are reciprocally enhanced in the Drosophila model

Extracellular aggregation of amyloid-beta (Aβ) and intracellular tau tangles are two major pathogenic hallmarks and critical factors of Alzheimer’s disease. A linear interaction between Aβ and tau protein has been characterized in several models. Aβ induces tau hyperphosphorylation through a complex mechanism; however, the master regulators involved in this linear process are still unclear. In our study with Drosophila melanogaster, we found that Aβ regulated tau hyperphosphorylation and toxicity by activating c-Jun N-terminal kinase. Importantly, Aβ toxicity was dependent on tau hyperphosphorylation, and flies with hypophosphorylated tau were insulated against Aβ-induced toxicity. Strikingly, tau accumulation reciprocally interfered with Aβ degradation and correlated with the reduction in mRNA expression of genes encoding Aβ-degrading enzymes, including dNep1, dNep3, dMmp2, dNep4, and dIDE. Our results indicate that Aβ and tau protein work synergistically to further accelerate Alzheimer’s disease progression and may be considered as a combined target for future development of Alzheimer’s disease therapeutics.

Novel and PCR ready rapid DNA isolation from Drosophila

INTRODUCTION

Isolation of genomic DNA is an initial step in molecular biology techniques. The quality of isolated DNA depends on procedures and chemicals, as well as source and types of the sample used. Several existing procedures are expensive and time consuming. In this study, we isolated high quality genomic DNA with an inexpensive and least time consuming procedure using Drosophila melanogaster flies, larvae, and pupae.

METHODS

Drosophila melanogaster samples were collected from pre-cultured bottles, and genomic DNA was extracted using a proposed novel and PCR-ready method from three different pools of flies [PF1, PF2, and PF3], similarly from larvae and pupae [PL1, PL2, PL3, PP1, PP2, and PP3, respectively]. Isolated genomic DNA was subjected to PCR amplification with different dilutions using the COI gene and further amplicons were used for RAPD and DNA sequencing.

RESULTS

The high quality of isolated genomic DNA was confirmed by 0.8% agarose gel electrophoresis and the purity and quantity of the DNA isolated from single fly, larva and pupa was similar to the purity and quantity of the DNA isolated using the NucleoSpin^R Tissue kit method. Isolated genomic DNA was successfully amplified when the template was diluted in the ratio of 1:10. Further successful RAPD amplification and sequencing analysis of the COI gene confirms the efficiency of the downstream application of the proposed novel method.

CONCLUSION

The present Novel and PCR ready rapid DNA isolation method will be potentially beneficial, and it can be successfully used for quick isolation of high molecular weight DNA from Drosophila flies larvae and pupae for DNA barcoding, identification of new species, genotyping, RAPD analysis, etc. Moreover, it can also be easily scaled up for bulk preparations.

Neuroprotective properties of Solanum leaves in Transgenic Drosophila melanogaster model of Alzheimer's disease

INTRODUCTION

We investigated the effect of African eggplant (AE) (Solanum macrocarpon L) and Black nightshade (BN) (Solanum nigrum L) leaves; two tropical vegetables consumed by humans on behavioral, biochemical and histological indices in Drosophila melanogaster model of Alzheimer's disease (AD).

MATERIALS AND METHOD

Transgenic flies expressing human Amyloid Precursor Protein (hAPP) and β-secretase (hBACE 1) were exposed to the pulverized leaf samples (0.1 and 1.0%) in their diets for fourteen days. Thereafter, the flies were assessed for their behavioral indices and routine histology of brain cells. Furthermore, fly head homogenates were assayed for β-amyloid level, activities of acetylcholinesterase (AChE) and β-secretase (BACE-1), as well as oxidative stress markers.

RESULTS

Result showed that the significantly lower (p < 0.05) behavioral parameters (survival, locomotor performance and memory index), higher AChE and BACE-1 activities, β-amyloid, ROS and lipid peroxidation levels, as well as reduced antioxidant indices observed in the AD flies, were significantly ameliorated (p < 0.05) in AD flies treated with the leaf samples.

DISCUSSION

This study has showed that leaves of AE and BN ameliorated behavioral and biochemical indices in AD flies via neural enzyme modulatory, and antioxidant mechanisms.

CONCLUSION

Hence, this study further justifies the neuroprotective properties of both AE and BN.

Drosophila as a Model to Study the Mechanism of Nociception

Nociception refers to the process of encoding and processing noxious stimuli, which allow animals to detect and avoid potentially harmful stimuli. Several types of stimuli can trigger nociceptive sensory transduction, including thermal, noxious chemicals, and harsh mechanical stimulation that depend on the corresponding nociceptors. In view of the high evolutionary conservation of the mechanisms that govern nociception from Drosophila melanogaster to mammals, investigation in the fruit fly Drosophila help us understand how the sensory nervous system works and what happen in nociception. Here, we present an overview of currently identified conserved genetics of nociception, the nociceptive sensory neurons responsible for detecting noxious stimuli, and various assays for evaluating different nociception. Finally, we cover development of anti-pain drug using fly model. These comparisons illustrate the value of using Drosophila as model for uncovering nociception mechanisms, which are essential for identifying new treatment goals and developing novel analgesics that are applicable to human health.

Improving one-step scarless genome editing in Drosophila melanogaster by combining ovoD co-CRISPR selection with sgRNA target site masking

The precise and rapid construction of alleles through CRISPR/Cas9-mediated genome engineering renders Drosophila melanogaster a powerful animal system for molecular structure–function analyses and human disease models. Application of the ovo^D co-selection method offers expedited generation and enrichment of scarlessly edited alleles without the need for linked transformation markers, which specifically in the case of exon editing can impact allele usability. However, we found that knockin procedures by homology-directed repair (HDR) under ovo^D co-selection resulted in low transformation efficiency. This is likely due to repeated rounds of Cas9 cleavage of HDR donor and/or engineered genomic locus DNA, as noted for other CRISPR/Cas9 editing strategies before, impeding the recovery of correctly edited alleles. Here we provide a one-step protocol to improve the generation of scarless alleles by ovo^D-co-selection with single-guide RNA (sgRNA) binding site masking. Using this workflow, we constructed human disease alleles for two Drosophila genes, unc-13/CG2999 and armadillo/CG11579. We show and quantify how a known countermeasure, the insertion of silent point mutations into protospacer adjacent motif (PAM) or sgRNA homology regions, can potently suppress unintended sequence modifications during CRISPR/Cas9 genome editing of D. melanogaster under ovo^D co-selection. This strongly increased the recovery frequency of disease alleles.

Drosophila as a model to explore secondary injury cascades after traumatic brain injury

Drosophilae are emerging as a valuable model to study traumatic brain injury (TBI)-induced secondary injury cascades that drive persisting neuroinflammation and neurodegenerative pathology that imposes significant risk for long-term neurological deficits. As in mammals, TBI in Drosophila triggers axonal injury, metabolic crisis, oxidative stress, and a robust innate immune response. Subsequent neurodegeneration stresses quality control systems and perpetuates an environment for neuroprotection, regeneration, and delayed cell death via highly conserved cell signaling pathways. Fly injury models continue to be developed and validated for both whole-body and head-specific injury to isolate, evaluate, and modulate these parallel pathways. In conjunction with powerful genetic tools, the ability for longitudinal evaluation, and associated neurological deficits that can be tested with established behavioral tasks, Drosophilae are an attractive model to explore secondary injury cascades and therapeutic intervention after TBI. Here, we review similarities and differences between mammalian and fly pathophysiology and highlight strategies for their use in translational neurotrauma research.

The power of imaging to understand extracellular vesicle biology in vivo

Extracellular vesicles (EVs) are nano-sized lipid bilayer vesicles released by virtually every cell type. EVs have diverse biological activities, ranging from roles in development and homeostasis to cancer progression, which has spurred the development of EVs as disease biomarkers and drug nanovehicles. Owing to the small size of EVs, however, most studies have relied on isolation and biochemical analysis of bulk EVs separated from biofluids. Although informative, these approaches do not capture the dynamics of EV release, biodistribution, and other contributions to pathophysiology. Recent advances in live and high-resolution microscopy techniques, combined with innovative EV labeling strategies and reporter systems, provide new tools to study EVs in vivo in their physiological environment and at the single-vesicle level. Here we critically review the latest advances and challenges in EV imaging, and identify urgent, outstanding questions in our quest to unravel EV biology and therapeutic applications.

In Vivo and In Vitro Assays Evaluating the Biological Activity of Taurine, Glucose and Energetic Beverages

Taurine is one of the main ingredients used in energy drinks which are highly consumed in adolescents for their sugary taste and stimulating effect. With energy drinks becoming a worldwide phenomenon, the biological effects of these beverages must be evaluated in order to fully comprehend the potential impact of these products on the health due to the fact nutrition is closely related to science since the population consumes food to prevent certain diseases. Therefore, the aim of this study was to evaluate the biological effects of taurine, glucose, classic Red Bull® and sugar-free Red Bull® in order to check the food safety and the nutraceutical potential of these compounds, characterising different endpoints: (i) Toxicology, antitoxicology, genotoxicology and life expectancy assays were performed in the Drosophila melanogaster model organism; (ii) The in vitro chemopreventive activity of testing compounds was determined by assessing their cytotoxicity, the proapoptotic DNA-damage capability to induce internucleosomal fragmentation, the strand breaks activity and the modulator role on the methylation status of genomic repetitive sequences of HL-60 promyelocytic cells. Whereas none tested compounds showed toxic or genotoxic effect, all tested compounds exerted antitoxic and antigenotoxic activity in Drosophila. Glucose, classic Red Bull® and sugar-free Red Bull® were cytotoxic in HL-60 cell line. Classic Red Bull® induced DNA internucleosomal fragmentation although none of them exhibited DNA damage on human leukaemia cells. In conclusion, the tested compounds are safe on Drosophila melanogaster and classic Red Bull® could overall possess nutraceutical potential in the in vivo and in vitro model used in this study. Besides, taurine could holistically be one of the bioactive compounds responsible for the biological activity of classic Red Bull®.

The utilization of small non-mammals in traumatic brain injury research: A systematic review

Traumatic brain injury (TBI) is the leading cause of death and disability worldwide and has complicated underlying pathophysiology. Numerous TBI animal models have been developed over the past decade to effectively mimic the human TBI pathophysiology. These models are of mostly mammalian origin including rodents and non-human primates. However, the mammalian models demanded higher costs and have lower throughput often limiting the progress in TBI research. Thus, this systematic review aims to discuss the potential benefits of non-mammalian TBI models in terms of their face validity in resembling human TBI. Three databases were searched as follows: PubMed, Scopus, and Embase, for original articles relating to non-mammalian TBI models, published between January 2010 and December 2019. A total of 29 articles were selected based on PRISMA model for critical appraisal. Zebrafish, both larvae and adult, was found to be the most utilized non-mammalian TBI model in the current literature, followed by the fruit fly and roundworm. In conclusion, non-mammalian TBI models have advantages over mammalian models especially for rapid, cost-effective, and reproducible screening of effective treatment strategies and provide an opportunity to expedite the advancement of TBI research.

Multiple mechanisms drive genomic adaptation to extreme O2 levels in Drosophila melanogaster

To detect the genomic mechanisms underlying evolutionary dynamics of adaptation in sexually reproducing organisms, we analyze multigenerational whole genome sequences of Drosophila melanogaster adapting to extreme O₂ conditions over an experiment conducted for nearly two decades. We develop methods to analyze time-series genomics data and predict adaptive mechanisms. Here, we report a remarkable level of synchronicity in both hard and soft selective sweeps in replicate populations as well as the arrival of favorable de novo mutations that constitute a few asynchronized sweeps. We additionally make direct experimental observations of rare recombination events that combine multiple alleles on to a single, better-adapted haplotype. Based on the analyses of the genes in genomic intervals, we provide a deeper insight into the mechanisms of genome adaptation that allow complex organisms to survive harsh environments.

The genomic details of adaptation to extreme environments remain challenging to characterize. Using new methods to analyze flies experimentally evolved to survive extreme O₂ conditions, the authors find a surprising level of synchronicity in selective sweeps, de novo mutations and adaptive recombination events.

The Neurotransmitters Involved in Drosophila Alcohol-Induced Behaviors

Alcohol is a widely used and abused substance with numerous negative consequences for human health and safety. Historically, alcohol's widespread, non-specific neurobiological effects have made it a challenge to study in humans. Therefore, model organisms are a critical tool for unraveling the mechanisms of alcohol action and subsequent effects on behavior. Drosophila melanogaster is genetically tractable and displays a vast behavioral repertoire, making it a particularly good candidate for examining the neurobiology of alcohol responses. In addition to being experimentally amenable, Drosophila have high face and mechanistic validity: their alcohol-related behaviors are remarkably consistent with humans and other mammalian species, and they share numerous conserved neurotransmitters and signaling pathways. Flies have a long history in alcohol research, which has been enhanced in recent years by the development of tools that allow for manipulating individual Drosophila neurotransmitters. Through advancements such as the GAL4/UAS system and CRISPR/Cas9 mutagenesis, investigation of specific neurotransmitters in small subsets of neurons has become ever more achievable. In this review, we describe recent progress in understanding the contribution of seven neurotransmitters to fly behavior, focusing on their roles in alcohol response: dopamine, octopamine, tyramine, serotonin, glutamate, GABA, and acetylcholine. We chose these small-molecule neurotransmitters due to their conservation in mammals and their importance for behavior. While neurotransmitters like dopamine and octopamine have received significant research emphasis regarding their contributions to behavior, others, like glutamate, GABA, and acetylcholine, remain relatively unexplored. Here, we summarize recent genetic and behavioral findings concerning these seven neurotransmitters and their roles in the behavioral response to alcohol, highlighting the fitness of the fly as a model for human alcohol use.

Pharmacological Treatment of Alzheimer's Disease: Insights from Drosophila melanogaster

Aging is an ineluctable law of life. During the process of aging, the occurrence of neurodegenerative disorders is prevalent in the elderly population and the predominant type of dementia is Alzheimer’s disease (AD). The clinical symptoms of AD include progressive memory loss and impairment of cognitive functions that interfere with daily life activities. The predominant neuropathological features in AD are extracellular β-amyloid (Aβ) plaque deposition and intracellular neurofibrillary tangles (NFTs) of hyperphosphorylated Tau. Because of its complex pathobiology, some tangible treatment can only ameliorate the symptoms, but not prevent the disease altogether. Numerous drugs during pre-clinical or clinical studies have shown no positive effect on the disease outcome. Therefore, understanding the basic pathophysiological mechanism of AD is imperative for the rational design of drugs that can be used to prevent this disease. Drosophilamelanogaster has emerged as a highly efficient model system to explore the pathogenesis and treatment of AD. In this review we have summarized recent advancements in the pharmacological research on AD using Drosophila as a model species, discussed feasible treatment strategies and provided further reference for the mechanistic study and treatment of age-related AD.

CRISPR/Cas9 mediated genetic resource for unknown kinase and phosphatase genes in Drosophila

Kinases and phosphatases are crucial for cellular processes and animal development. Various sets of resources in Drosophila have contributed significantly to the identification of kinases, phosphatases and their regulators. However, there are still many kinases, phosphatases and associate genes with unknown functions in the Drosophila genome. In this study, we utilized a CRISPR/Cas9 strategy to generate stable mutants for these unknown kinases, phosphatases and associate factors in Drosophila. For all the 156 unknown gene loci, we totally obtained 385 mutant alleles of 105 candidates, with 18 failure due to low efficiency of selected gRNAs and other 33 failure due to few recovered F0, which indicated high probability of lethal genes. From all the 105 mutated genes, we observed 9 whose mutants were lethal and another 4 sterile, most of which with human orthologs referred in OMIM, representing their huge value for human disease research. Here, we deliver these mutants as an open resource for more interesting studies.

Functional Genomics of Epilepsy and Associated Neurodevelopmental Disorders Using Simple Animal Models: From Genes, Molecules to Brain Networks

The genetic diagnosis of patients with seizure disorders has been improved significantly by the development of affordable next-generation sequencing technologies. Indeed, in the last 20 years, dozens of causative genes and thousands of associated variants have been described and, for many patients, are now considered responsible for their disease. However, the functional consequences of these mutations are often not studied in vivo, despite such studies being central to understanding pathogenic mechanisms and identifying novel therapeutic avenues. One main roadblock to functionally characterizing pathogenic mutations is generating and characterizing in vivo mammalian models carrying clinically relevant variants in specific genes identified in patients. Although the emergence of new mutagenesis techniques facilitates the production of rodent mutants, the fact that early development occurs internally hampers the investigation of gene function during neurodevelopment. In this context, functional genomics studies using simple animal models such as flies or fish are advantageous since they open a dynamic window of investigation throughout embryonic development. In this review, we will summarize how the use of simple animal models can fill the gap between genetic diagnosis and functional and phenotypic correlates of gene function in vivo. In particular, we will discuss how these simple animals offer the possibility to study gene function at multiple scales, from molecular function (i.e., ion channel activity), to cellular circuit and brain network dynamics. As a result, simple model systems offer alternative avenues of investigation to model aspects of the disease phenotype not currently possible in rodents, which can help to unravel the pathogenic substratum in vivo.

Alzheimer's Disease and Sleep-Wake Disturbances: Amyloid, Astrocytes, and Animal Models

Sleep-wake abnormalities are common in patients with Alzheimer's disease, and can be a major reason for institutionalization. However, an emerging concept is that these sleep-wake disturbances are part of the causal pathway accelerating the neurodegenerative process. Recently, new findings have provided intriguing evidence for a positive feedback loop between sleep-wake dysfunction and β-amyloid (Aβ) aggregation. Studies in both humans and animal models have shown that extended periods of wakefulness increase Aβ levels and aggregation, and accumulation of Aβ causes fragmentation of sleep. This perspective is aimed at presenting evidence supporting causal links between sleep-wake dysfunction and aggregation of Aβ peptide in Alzheimer's disease, and explores the role of astrocytes, a specialized type of glial cell, in this context underlying Alzheimer's disease pathology. The utility of current animal models and the unexplored potential of alternative animal models for testing mechanisms involved in the reciprocal relationship between sleep disruption and Aβ are also discussed.Dual Perspectives Companion Paper: Microglia-Mediated Synapse Loss in Alzheimer's Disease by Lawrence Rajendran and Rosa Paolicelli.

Studying alcohol use disorder using Drosophila melanogaster in the era of 'Big Data'

Our understanding of the networks of genes and protein functions involved in Alcohol Use Disorder (AUD) remains incomplete, as do the mechanisms by which these networks lead to AUD phenotypes. The fruit fly (Drosophila melanogaster) is an efficient model for functional and mechanistic characterization of the genes involved in alcohol behavior. The fly offers many advantages as a model organism for investigating the molecular and cellular mechanisms of alcohol-related behaviors, and for understanding the underlying neural circuitry driving behaviors, such as locomotor stimulation, sedation, tolerance, and appetitive (reward) learning and memory. Fly researchers are able to use an extensive variety of tools for functional characterization of gene products. To understand how the fly can guide our understanding of AUD in the era of Big Data we will explore these tools, and review some of the gene networks identified in the fly through their use, including chromatin-remodeling, glial, cellular stress, and innate immunity genes. These networks hold great potential as translational drug targets, making it prudent to conduct further research into how these gene mechanisms are involved in alcohol behavior.

Dissecting Motor Neuron Disease With Drosophila melanogaster

Motor Neuron Disease (MND) typically affects patients during the later stages of life, and thus, MND is having an increasingly devastating impact on diagnosed individuals, their families and society. The umbrella term MND refers to diseases which cause the progressive loss of upper and/or lower motor neurons and a subsequent decrease in motor ability such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA). The study of these diseases is complex and has recently involved the use of genome-wide association studies (GWAS). However, in the case of MND, it has been difficult to identify the complex genetics involved in subtypes, and functional investigation of new candidate disease genes is warranted. Drosophila is a powerful model for addressing these complex diseases. The UAS/Gal4/Gal80 system allows for the upregulation of Drosophila genes, the “knockdown” of genes and the ectopic expression of human genes or mutations in a tissue-specific manner; often resulting in Drosophila models which exhibit typical MND disease pathologies. These can then be further interrogated to identify disease-modifying genes or mutations and disease pathways. This review will discuss two common MNDs and the current Drosophila models which are being used to research their genetic basis and the different pathologies of MND.

An assessment of the translational relevance of Drosophila in drug discovery

INTRODUCTION

Drosophila melanogaster offers a powerful expedient and economical system with facile genetics. Because of the high sequence and functional conservation with human disease-associated genes, it has been cardinal in deciphering disease mechanisms at the genetic and molecular level. Drosophila are amenable to and respond well to pharmaceutical treatment which coupled to their genetic tractability has led to discovery, repositioning, and validation of a number of compounds. Areas covered: This review summarizes the generation of fly models of human diseases, their advantages and use in elucidation of human disease mechanisms. Representative studies provide examples of the utility of this system in modeling diseases and the discovery, repositioning and testing on pharmaceuticals to ameliorate them. Expert opinion: Drosophila offers a facile and economical whole animal system with many homologous organs to humans, high functional conservation and established methods of generating and validating human disease models. Nevertheless, it remains relatively underused as a drug discovery tool probably because its relevance to mammalian systems remains under question. However, recent exciting success stories using Drosophila disease models for drug screening, repositioning and validation strongly suggest that fly models should figure prominently in the drug discovery pipeline from bench to bedside.

Mutagenic and recombinogenic assessment of widely used pesticides on Drosophila melanogaster

The mutagenic potential of selected widely used pesticides: p,p'-dichlorodiphenyltrichloroethane (DDT); fenitrothion; propoxur; deltamethrin, bifenthrin; imidacloprid and thiametoxam was assessed using the wing spot test. Third-instar larvae of standard Drosophila melanogaster cross (ST), trans-heterozygous for the third chromosome recessive markers, multiple wing hairs (mwh) and flare (flr3) were chronically exposed to test compounds. Feeding ended with pupation of the surviving larvae. Genetic changes induced in somatic cells of the wing’s imaginal discs, mutant spots observed in marker-heterozygous (MH) and balancer-heterozygous (BH) flies were compared using the wing spot test, to estimate the genotoxic effects of these pesticides. In conclusion, exposure to 30 mg/mL deltamethrin, 40 mg/mL imidacloprid, 100 µg/mL DDT showed mutagenic and recombinagenic effects in the Drosophila wing spot test. In addition the results of chronic treatments performed at high doses showed mutagenic and recombinagenic effects in both genotypes

Dme-Hsa Disease Database (DHDD): Conserved Human Disease-Related miRNA and Their Targeting Genes in Drosophila melanogaster

Abnormal expressions of microRNA (miRNA) can result in human diseases such as cancer and neurodegenerative diseases. MiRNA mainly exert their biological functions via repressing the expression of their target genes. Drosophila melanogaster (D. melanogaster) is an ideal model for studying the molecular mechanisms behind biological phenotypes, including human diseases. In this study, we collected human and D. melanogaster miRNA as well as known human disease-related genes. In total, we identified 136 human disease-related miRNA that are orthologous to 83 D. melanogaster miRNA by mapping "seed sequence", and 677 human disease-related genes that are orthologous to 734 D. melanogaster genes using the DRSC Integrative Ortholog Prediction Tool Furthermore, we revealed the target relationship between genes and miRNA using miRTarBase database and target prediction software, including miRanda and TargetScan. In addition, we visualized interaction networks and signalling pathways for these filtered miRNA and target genes. Finally, we compiled all the above data and information to generate a database designated DHDD This is the first comprehensive collection of human disease-related miRNA and their targeting genes conserved in a D. melanogaster database. The DHDD provides a resource for easily searching human disease-related miRNA and their disease-related target genes as well as their orthologs in D. melanogaster, and conveniently identifying the regulatory relationships among them in the form of a visual network.

Parental and preimaginal exposure to methylmercury disrupts locomotor activity and circadian rhythm of adult Drosophila melanogaster

Methylmercury (MeHg) is a well-known toxic pollutant. However, little is known about the effects of this toxic agent in an adult as a consequence of a parental or preimaginal exposure. This study used Drosophila melanogaster to investigate whether a parental or a preimaginal (eggs-larvae-pupae stages) exposure could impact parameters as viability, locomotor activity, and sleep patterns of fruit flies. Thus, we performed two exposure protocols. One where just parents were exposed to MeHg (0-12 µM) during 24 h, then flies were transferred to lay eggs in a healthy medium (without MeHg). In the other, flies were set to lay eggs in a MeHg medium, same concentrations, and discarded after this (preimaginal exposure). Viability was evaluated from egg to adult flies. F1 progeny was collected within 24 h and transferred to a fresh healthy medium. Sleep behavior analysis was performed using Drosophila Active Monitoring System (DAMS), and the locomotor activity was evaluated by climbing assay. Results have shown that the parental exposure had a significant impact on F1 progeny reducing viability and locomotor activity performance, but no significant circadian rhythm alterations. Whereas the preimaginal exposure had a stronger effect decreasing viability and locomotor activity, it also disrupted sleep patterns. MeHg preimaginal exposure showed a longer sleep duration and lower daily activity. Results corroborate the hypothesis that low MeHg exposure could trigger subclinical symptoms related to a 'neurotoxicological development effect'. Complementary investigations could clarify the underlying mechanisms of MeHg effects in neural functions due to parental and early development exposure to this toxicant.

Drosophila melanogaster as a Versatile Model Organism in Food and Nutrition Research

Drosophila melanogaster has been widely used in the biological sciences as a model organism. Drosophila has a relatively short life span of 60-80 days, which makes it attractive for life span studies. Moreover, approximately 60% of the fruit fly genes are orthologs to mammals. Thus, metabolic and signal transduction pathways are highly conserved. Maintenance and reproduction of Drosophila do not require sophisticated equipment and are rather cheap. Furthermore, there are fewer ethical issues involved in experimental Drosophila research compared with studies in laboratory rodents, such as rats and mice. Drosophila is increasingly recognized as a model organism in food and nutrition research. Drosophila is often fed complex solid diets based on yeast, corn, and agar. There are also so-called holidic diets available that are defined in terms of their amino acid, fatty acid, carbohydrate, vitamin, mineral, and trace element compositions. Feed intake, body composition, locomotor activity, intestinal barrier function, microbiota, cognition, fertility, aging, and life span can be systematically determined in Drosophila in response to dietary factors. Furthermore, diet-induced pathophysiological mechanisms including inflammation and stress responses may be evaluated in the fly under defined experimental conditions. Here, we critically evaluate Drosophila melanogaster as a versatile model organism in experimental food and nutrition research, review the corresponding data in the literature, and make suggestions for future directions of research.

Modeling Fragile X Syndrome in Drosophila

Intellectual disability (ID) and autism are hallmarks of Fragile X Syndrome (FXS), a hereditary neurodevelopmental disorder. The gene responsible for FXS is Fragile X Mental Retardation gene 1 (FMR1) encoding the Fragile X Mental Retardation Protein (FMRP), an RNA-binding protein involved in RNA metabolism and modulating the expression level of many targets. Most cases of FXS are caused by silencing of FMR1 due to CGG expansions in the 5'-UTR of the gene. Humans also carry the FXR1 and FXR2 paralogs of FMR1 while flies have only one FMR1 gene, here called dFMR1, sharing the same level of sequence homology with all three human genes, but functionally most similar to FMR1. This enables a much easier approach for FMR1 genetic studies. Drosophila has been widely used to investigate FMR1 functions at genetic, cellular, and molecular levels since dFMR1 mutants have many phenotypes in common with the wide spectrum of FMR1 functions that underlay the disease. In this review, we present very recent Drosophila studies investigating FMRP functions at genetic, cellular, molecular, and electrophysiological levels in addition to research on pharmacological treatments in the fly model. These studies have the potential to aid the discovery of pharmacological therapies for FXS.

In vivo bioassay to test the pathogenicity of missense human AIP variants

Background

Heterozygous germline loss-of-function mutations in the aryl hydrocarbon receptor-interacting protein gene (AIP) predispose to childhood-onset pituitary tumours. The pathogenicity of missense variants may pose difficulties for genetic counselling and family follow-up.

Objective

To develop an in vivo system to test the pathogenicity of human AIP mutations using the fruit fly Drosophila melanogaster.

Methods

We generated a null mutant of the Drosophila AIP orthologue, CG1847, a gene located on the Xchromosome, which displayed lethality at larval stage in hemizygous knockout male mutants (CG1847^exon1_3). We tested human missense variants of ‘unknown significance’, with ‘pathogenic’ variants as positive control.

Results

We found that human AIP can functionally substitute for CG1847, as heterologous overexpression of human AIP rescued male CG1847^exon1_3 lethality, while a truncated version of AIP did not restore viability. Flies harbouring patient-specific missense AIP variants (p.C238Y, p.I13N, p.W73R and p.G272D) failed to rescue CG1847^exon1_3 mutants, while seven variants (p.R16H, p.Q164R, p.E293V, p.A299V, p.R304Q, p.R314W and p.R325Q) showed rescue, supporting a non-pathogenic role for these latter variants corresponding to prevalence and clinical data.

Conclusion

Our in vivo model represents a valuable tool to characterise putative disease-causing human AIP variants and assist the genetic counselling and management of families carrying AIP variants.

Drosophila melanogaster Models of Friedreich's Ataxia

Friedreich's ataxia (FRDA) is a rare inherited recessive disorder affecting the central and peripheral nervous systems and other extraneural organs such as the heart and pancreas. This incapacitating condition usually manifests in childhood or adolescence, exhibits an irreversible progression that confines the patient to a wheelchair, and leads to early death. FRDA is caused by a reduced level of the nuclear-encoded mitochondrial protein frataxin due to an abnormal GAA triplet repeat expansion in the first intron of the human FXN gene. FXN is evolutionarily conserved, with orthologs in essentially all eukaryotes and some prokaryotes, leading to the development of experimental models of this disease in different organisms. These FRDA models have contributed substantially to our current knowledge of frataxin function and the pathogenesis of the disease, as well as to explorations of suitable treatments. Drosophila melanogaster, an organism that is easy to manipulate genetically, has also become important in FRDA research. This review describes the substantial contribution of Drosophila to FRDA research since the characterization of the fly frataxin ortholog more than 15 years ago. Fly models have provided a comprehensive characterization of the defects associated with frataxin deficiency and have revealed genetic modifiers of disease phenotypes. In addition, these models are now being used in the search for potential therapeutic compounds for the treatment of this severe and still incurable disease.

Metabolomics: State-of-the-Art Technologies and Applications on Drosophila melanogaster

Metabolomics is one of the latest "omics" technology concerned with the high-throughput identification and quantification of metabolites, the final products of cellular processes. The revealed data provide an instantaneous snapshot of an organism's metabolic pathways, which can be used to explain its phenotype or physiology. On the other hand, Drosophila has shown its power in studying metabolism and related diseases. At this stage, we have the state-of-the-art knowledge in place: a potential candidate to study cellular metabolism (Drosophila melanogaster) and a powerful methodology for metabolic network decipherer (metabolomics). Yet missing is advanced metabolomics technologies like isotope-assisted metabolomics optimized for Drosophila. In this chapter, we will discuss on the current status and future perspectives in technologies and applications of Drosophila metabolomics.

Genetic human prion disease modelled in PrP transgenic Drosophila

Inherited human prion diseases, such as fatal familial insomnia (FFI) and familial Creutzfeldt–Jakob disease (fCJD), are associated with autosomal dominant mutations in the human prion protein gene PRNP and accumulation of PrP^Sc, an abnormal isomer of the normal host protein PrP^C, in the brain of affected individuals. PrP^Sc is the principal component of the transmissible neurotoxic prion agent. It is important to identify molecular pathways and cellular processes that regulate prion formation and prion-induced neurotoxicity. This will allow identification of possible therapeutic interventions for individuals with, or at risk from, genetic human prion disease. Increasingly, Drosophila has been used to model human neurodegenerative disease. An important unanswered question is whether genetic prion disease with concomitant spontaneous prion formation can be modelled in Drosophila. We have used pUAST/PhiC31-mediated site-directed mutagenesis to generate Drosophila transgenic for murine or hamster PrP (prion protein) that carry single-codon mutations associated with genetic human prion disease. Mouse or hamster PrP harbouring an FFI (D178N) or fCJD (E200K) mutation showed mild Proteinase K resistance when expressed in Drosophila. Adult Drosophila transgenic for FFI or fCJD variants of mouse or hamster PrP displayed a spontaneous decline in locomotor ability that increased in severity as the flies aged. Significantly, this mutant PrP-mediated neurotoxic fly phenotype was transferable to recipient Drosophila that expressed the wild-type form of the transgene. Collectively, our novel data are indicative of the spontaneous formation of a PrP-dependent neurotoxic phenotype in FFI- or CJD-PrP transgenic Drosophila and show that inherited human prion disease can be modelled in this invertebrate host.

Drosophila melanogaster "a potential model organism" for identification of pharmacological properties of plants/plant-derived components

Plants/plant-derived components have been used from ancient times to treat/cure several human diseases. Plants and their parts possess several chemical components that play the vital role in the improvement of human health and their life expectancy. Allopathic medicines have been playing a key role in the treatment of several diseases. Though allopathic medicines provide fast relief, long time consumption cause serious health concerns such as hyperallergic reactions, liver damage, etc. So, the study of medicinal plants which rarely cause any side effect is very important to mankind. Plants contain many health benefit properties like antioxidant, anti-aging, neuroprotective, anti-genotoxic, anti-mutagenic and bioinsecticidal activity. Thus, identification of pharmacological properties of plants/plant-derived components are of utmost importance to be explored. Several model organisms have been used to identify the pharmacological properties of the different plants or active components therein and Drosophila is one of them. Drosophila melanogaster "fruit fly" is a well understood, high-throughput model organism being used more than 110 years to study the different biological aspects related to the development and diseases. Most of the developmental and cell signaling pathways and ∼75% human disease-related genes are conserved between human and Drosophila. Using Drosophila, one can easily analyze the pharmacological properties of plants/plant-derived components by performing several assays available with flies such as survivorship, locomotor, antioxidant, cell death, etc. The current review focuses on the potential of Drosophila melanogaster for the identification of medicinal/pharmacological properties associated with plants/plant-derived components.

Drosophila and genome-wide association studies: a review and resource for the functional dissection of human complex traits

Human genome-wide association studies (GWAS) have successfully identified thousands of susceptibility loci for common diseases with complex genetic etiologies. Although the susceptibility variants identified by GWAS usually have only modest effects on individual disease risk, they contribute to a substantial burden of trait variation in the overall population. GWAS also offer valuable clues to disease mechanisms that have long proven to be elusive. These insights could lead the way to breakthrough treatments; however, several challenges hinder progress, making innovative approaches to accelerate the follow-up of results from GWAS an urgent priority. Here, we discuss the largely untapped potential of the fruit fly, Drosophila melanogaster, for functional investigation of findings from human GWAS. We highlight selected examples where strong genomic conservation with humans along with the rapid and powerful genetic tools available for flies have already facilitated fine mapping of association signals, elucidated gene mechanisms, and revealed novel disease-relevant biology. We emphasize current research opportunities in this rapidly advancing field, and present bioinformatic analyses that systematically explore the applicability of Drosophila for interrogation of susceptibility signals implicated in more than 1000 human traits, based on all GWAS completed to date. Thus, our discussion is targeted at both human geneticists seeking innovative strategies for experimental validation of findings from GWAS, as well as the Drosophila research community, by whom ongoing investigations of the implicated genes will powerfully inform our understanding of human disease.

Role of Choline in the Modulation of Degenerative Processes: In Vivo and In Vitro Studies

The purpose of the present study was to examine the nutraceutical potential of choline as an added value to its well-known brain nutrient role. Several toxicity, antitoxicity, genotoxicity, antigenotoxicity, and longevity endpoints were checked in the somatic mutation and recombination test in in vivo Drosophila animal model. Cytotoxicity in human leukemia-60 cell line (HL-60) promyelocytic and NIH3T3 mouse fibroblast cells, proapoptotic DNA fragmentation, comet assay, methylation status, and macroautophagy (MA) activity were tested in in vitro assays. Choline is not only safe but it is also able to protect against the DNA damage caused by an oxidative genotoxin. Moreover, it improves the life extension in the animal model. The in vitro results show that it is able to exhibit genetic damage against leukemia HL-60 cells. Single-strand breaks in DNA are observed at the molecular level in treatments with choline, although only a significant hypermethylation on the long interspersed elements-1 and a hypomethylation on the satellite-alpha DNA repetitive DNA sequences of HL-60 cells at the lowest concentration (0.447 mM) were observed. Besides, choline decreased MA at the lower assayed concentration and the MA response to topoisomerase inhibitor (etoposide) is maintained in the presence of treatment with 0.22 mM choline. Taking into account the hopeful results obtained in the in vivo and in vitro assays, choline could be proposed as a substance with an important nutraceutical value for different purposes.

Role of Drosophila Amyloid Precursor Protein in Memory Formation

The amyloid precursor protein (APP) is a membrane protein engaged in complex proteolytic pathways. APP and its derivatives have been shown to play a central role in Alzheimer’s disease (AD), a progressive neurodegenerative disease characterized by memory decline. Despite a huge effort from the research community, the primary cause of AD remains unclear, making it crucial to better understand the physiological role of the APP pathway in brain plasticity and memory. Drosophila melanogaster is a model system well-suited to address this issue. Although relatively simple, the fly brain is highly organized, sustains several forms of learning and memory, and drives numerous complex behaviors. Importantly, molecules and mechanisms underlying memory processes are conserved from flies to mammals. The fly encodes a single non-essential APP homolog named APP-Like (APPL). Using in vivo inducible RNA interference strategies, it was shown that APPL knockdown in the mushroom bodies (MB)—the central integrative brain structure for olfactory memory—results in loss of memory. Several APPL derivatives, such as secreted and full-length membrane APPL, may play different roles in distinct types of memory phases. Furthermore, overexpression of Drosophila amyloid peptide exacerbates the memory deficit caused by APPL knockdown, thus potentiating memory decline. Data obtained in the fly support the hypothesis that APP acts as a transmembrane receptor, and that disruption of its normal function may contribute to cognitive impairment during early AD.

Membrane protein trafficking in Drosophila photoreceptor cells

Membrane protein trafficking occurs throughout the lifetime of neurons and includes the initial protein synthesis and anterograde transport to the plasma membrane as well as internalization, degradation, and recycling of plasma membrane proteins. Defects in protein trafficking can result in neuronal degeneration and underlie blinding diseases such as retinitis pigmentosa as well as other neuronal disorders. Drosophila photoreceptor cells have emerged as a model system for identifying the components and mechanisms involved in membrane protein trafficking in neurons. Here we summarize the current knowledge about trafficking of three Drosophila phototransduction proteins, the visual pigment rhodopsin and the two light-activated ion channels TRP (transient receptor potential) and TRPL (TRP-like). Despite some common requirements shared by rhodopsin and TRP, details in the trafficking of these proteins differ considerably, suggesting the existence of several trafficking pathways for these photoreceptor proteins.

Analysis of Drosophila melanogaster proteome dynamics during embryonic development by a combination of label-free proteomics approaches

During embryogenesis, organisms undergo considerable cellular remodelling requiring the combined action of thousands of proteins. In case of the well-studied model Drosophila melanogaster, transcriptomic studies, most notably from the modENCODE project, have described in detail changes in gene expression at the mRNA level across development. Although such data are clearly very useful to understand how the genome is regulated during embryogenesis, it is important to understand how changes in gene expression are reflected at the level of the proteome. In this study, we describe a combination of two quantitative label-free approaches, SWATH and data-dependent acquisition, to monitor changes in protein expression across a timecourse of D. melanogaster embryonic development. We demonstrate that both approaches provide robust and reproducible methods for the analysis of proteome changes. In a preliminary analysis of Drosophila embryogenesis, we identified several pathways, including the heat-shock response, nuclear protein import and energy production that are regulated during embryo development. In some cases changes in protein expression mirrored transcript levels across development, whereas other proteins showed signatures of post-transcriptional regulation. Taken together, our pilot study provides a solid platform for a more detailed exploration of the embryonic proteome.

In Vivo and In Vitro Genotoxic and Epigenetic Effects of Two Types of Cola Beverages and Caffeine: A Multiassay Approach

The aim of this work was to assess the biological and food safety of two different beverages: Classic Coca Cola™ (CCC) and Caffeine-Free Coca Cola (CFCC). To this end, we determined the genotoxicological and biological effects of different doses of lyophilised CCC and CFCC and Caffeine (CAF), the main distinctive constituent. Their toxic/antitoxic, genotoxic/antigenotoxic, and chronic toxicity (lifespan assay) effects were determined in vivo using the Drosophila model. Their cytotoxic activities were determined using the HL-60 in vitro cancer model. In addition, clastogenic DNA toxicity was measured using internucleosomal fragmentation and SCGE assays. Their epigenetic effects were assessed on the HL-60 methylation status using some repetitive elements. The experimental results showed a slight chemopreventive effect of the two cola beverages against HL-60 leukaemia cells, probably mediated by nonapoptotic mechanisms. Finally, CCC and CAF induced a global genome hypomethylation evaluated in LINE-1 and Alu M1 repetitive elements. Overall, we demonstrated for the first time the safety of this famous beverage in in vivo and in vitro models.

Why Quantification Matters: Characterization of Phenotypes at the Drosophila Larval Neuromuscular Junction

Most studies on morphogenesis rely on qualitative descriptions of how anatomical traits are affected by the disruption of specific genes and genetic pathways. Quantitative descriptions are rarely performed, although genetic manipulations produce a range of phenotypic effects and variations are observed even among individuals within control groups. Emerging evidence shows that morphology, size and location of organelles play a previously underappreciated, yet fundamental role in cell function and survival. Here we provide step-by-step instructions for performing quantitative analyses of phenotypes at the Drosophila larval neuromuscular junction (NMJ). We use several reliable immuno-histochemical markers combined with bio-imaging techniques and morphometric analyses to examine the effects of genetic mutations on specific cellular processes. In particular, we focus on the quantitative analysis of phenotypes affecting morphology, size and position of nuclei within the striated muscles of Drosophila larvae. The Drosophila larval NMJ is a valuable experimental model to investigate the molecular mechanisms underlying the structure and the function of the neuromuscular system, both in health and disease. However, the methodologies we describe here can be extended to other systems as well.

What can flies tell us about zinc homeostasis?

Zinc is an essential micronutrient for all organisms. For multicellular organisms, zinc uptake, storage, distribution and export are tightly regulated at both cellular and organismal levels, to cope with the multiple requirements versus the toxicity of the metal ion. During the past decade, the fruit fly Drosophila melanogaster has become an important model organism for the elucidation of metazoan zinc homeostasis. This review describes our current knowledge of various zinc transporters in Drosophila, with an emphasis on the process of dietary zinc uptake in the fly. We also discuss how Drosophila was used as a model to facilitate our understanding of the role of zinc in neurodegenerative diseases.

5-Hydroxymethylation-associated epigenetic modifiers of Alzheimer's disease modulate Tau-induced neurotoxicity

Alzheimer's disease (AD) is a chronic neurodegenerative disorder characterized by progressive deterioration of cognitive function. Pathogenesis of AD is incompletely understood; evidence suggests a role for epigenetic regulation, in particular the cytosine modifications 5-methylcytosine and 5-hydroxymethylcytosine (5hmC). 5hmC is enriched in the nervous system and displays neurodevelopment and age-related changes. To determine the role of 5hmC in AD, we performed genome-wide analyses of 5hmC in DNA from prefrontal cortex of post-mortem AD patients, and RNA-Seq to correlate changes in 5hmC with transcriptional changes. We identified 325 genes containing differentially hydroxymethylated loci (DhMLs) in both discovery and replication datasets. These are enriched for pathways involved in neuron projection development and neurogenesis. Of these, 140 showed changes in gene expression. Proteins encoded by these genes form direct protein-protein interactions with AD-associated genes, expanding the network of genes implicated in AD. We identified AD-associated single nucleotide polymorphisms (SNPs) located within or near DhMLs, suggesting these SNPs may identify regions of epigenetic gene regulation that play a role in AD pathogenesis. Finally, using an existing AD fly model, we showed some of these genes modulate AD-associated toxicity. Our data implicate neuronal projection development and neurogenesis pathways as potential targets in AD. By incorporating epigenomic and transcriptomic data with genome-wide association studies data, with verification in the Drosophila model, we can expand the known network of genes involved in disease pathogenesis and identify epigenetic modifiers of Alzheimer's disease.