scholarly journals C. elegans expressing D76N β2-microglobulin: a model for in vivo screening of drug candidates targeting amyloidosis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Giulia Faravelli ◽  
Sara Raimondi ◽  
Loredana Marchese ◽  
Frederick A. Partridge ◽  
Cristina Soria ◽  
...  
Keyword(s):  
Genetic Model ◽  
Model Organism ◽  
Chemical Screening ◽  
C Elegans ◽  
Drug Candidates ◽  
Molecular Events ◽  
Wild Type Phenotype ◽  
Familial Form ◽  
Automated Phenotyping

AbstractThe availability of a genetic model organism with which to study key molecular events underlying amyloidogenesis is crucial for elucidating the mechanism of the disease and the exploration of new therapeutic avenues. The natural human variant of β2-microglobulin (D76N β2-m) is associated with a fatal familial form of systemic amyloidosis. Hitherto, no animal model has been available for studying in vivo the pathogenicity of this protein. We have established a transgenic C. elegans line, expressing the human D76N β2-m variant. Using the INVertebrate Automated Phenotyping Platform (INVAPP) and the algorithm Paragon, we were able to detect growth and motility impairment in D76N β2-m expressing worms. We also demonstrated the specificity of the β2-m variant in determining the pathological phenotype by rescuing the wild type phenotype when β2-m expression was inhibited by RNA interference (RNAi). Using this model, we have confirmed the efficacy of doxycycline, an inhibitor of the aggregation of amyloidogenic proteins, in rescuing the phenotype. In future, this C. elegans model, in conjunction with the INVAPP/Paragon system, offers the prospect of high-throughput chemical screening in the search for new drug candidates.

C. elegans models of neuromuscular diseases expedite translational research

2010 ◽  
Vol 1 (3) ◽  
Author(s):  
James Sleigh ◽  
David Sattelle
Keyword(s):  
Large Scale ◽  
Genetic Model ◽  
Muscular Atrophy ◽  
Neuromuscular Disorders ◽  
Neuromuscular Diseases ◽  
Model Organism ◽  
Disease Genes ◽  
Chemical Library ◽  
C Elegans

AbstractThe nematode Caenorhabditis elegans is a genetic model organism and the only animal with a complete nervous system wiring diagram. With only 302 neurons and 95 striated muscle cells, a rich array of mutants with defective locomotion and the facility for individual targeted gene knockdown by RNA interference, it lends itself to the exploration of gene function at nerve muscle junctions. With approximately 60% of human disease genes having a C. elegans homologue, there is growing interest in the deployment of lowcost, high-throughput, drug screens of nematode transgenic and mutant strains mimicking aspects of the pathology of devastating human neuromuscular disorders. Here we explore the contributions already made by C. elegans to our understanding of muscular dystrophies (Duchenne and Becker), spinal muscular atrophy, amyotrophic lateral sclerosis, Friedreich’s ataxia, inclusion body myositis and the prospects for contributions to other neuromuscular disorders. A bottleneck to low-cost, in vivo, large-scale chemical library screening for new candidate therapies has been rapid, automated, behavioural phenotyping. Recent progress in quantifying simple swimming (thrashing) movements is making such screening possible and is expediting the translation of drug candidates towards the clinic.

scholarly journals Caenorhabditis elegans as an in vivo Model to Assess Amphetamine Tolerance

2021 ◽  
pp. 1-9
Author(s):  
Dayana Torres Valladares ◽  
Sirisha Kudumala ◽  
Murad Hossain ◽  
Lucia Carvelli
Keyword(s):  
Caenorhabditis Elegans ◽  
Molecular Mechanisms ◽  
Drugs Of Abuse ◽  
Genetic Model ◽  
In Vivo Model ◽  
C Elegans ◽  
Hyperactivity Disorder ◽  
In Vitro Data

Amphetamine is a potent psychostimulant also used to treat attention deficit/hyperactivity disorder and narcolepsy. In vivo and in vitro data have demonstrated that amphetamine increases the amount of extra synaptic dopamine by both inhibiting reuptake and promoting efflux of dopamine through the dopamine transporter. Previous studies have shown that chronic use of amphetamine causes tolerance to the drug. Thus, since the molecular mechanisms underlying tolerance to amphetamine are still unknown, an animal model to identify the neurochemical mechanisms associated with drug tolerance is greatly needed. Here we took advantage of a unique behavior caused by amphetamine in <i>Caenorhabditis elegans</i> to investigate whether this simple, but powerful, genetic model develops tolerance following repeated exposure to amphetamine. We found that at least 3 treatments with 0.5 mM amphetamine were necessary to see a reduction in the amphetamine-induced behavior and, thus, to promote tolerance. Moreover, we found that, after intervals of 60/90 minutes between treatments, animals were more likely to exhibit tolerance than animals that underwent 10-minute intervals between treatments. Taken together, our results show that <i>C. elegans</i> is a suitable system to study tolerance to drugs of abuse such as amphetamines.

scholarly journals Alzheimer’s disease-relevant tau modifications selectively impact neurodegeneration and mitophagy in a novel C. elegans single-copy transgenic model

2020 ◽  
Author(s):  
Sanjib Guha ◽  
Sarah Fischer ◽  
Gail VW Johnson ◽  
Keith Nehrke
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Genetic Model ◽  
Neurodegenerative Disorder ◽  
Model Organism ◽  
Single Copy ◽  
Mitochondrial Stress ◽  
C Elegans ◽  
Touch Receptor Neurons ◽  
New Perspective

ABSTRACTBackgroundA defining pathological hallmark of the progressive neurodegenerative disorder Alzheimer’s disease (AD) is the accumulation of misfolded tau with abnormal post-translational modifications (PTMs). These include phosphorylation at Threonine 231 (T231) and acetylation at Lysine 274 (K274) and at Lysine 281 (K281). Although tau is recognized to play a central role in pathogenesis of AD, the precise mechanisms by which these abnormal PTMs contribute to the neural toxicity of tau is unclear.MethodsHuman 0N4R tau (wild type) was expressed in touch receptor neurons of the genetic model organism C. elegans through single-copy gene insertion. Defined mutations were then introduced into the single-copy tau transgene through CRISPR-Cas9 genome editing. These mutations included T231E and T231A, to mimic phosphorylation and phospho-ablation of a commonly observed pathological epitope, respectively, and K274/281Q, to mimic disease-associated lysine acetylation. Stereotypical touch response assays were used to assess behavioral defects in the transgenic strains as a function of age, and genetically-encoded fluorescent biosensors were used to measure the morphological dynamics and turnover of touch neuron mitochondria.ResultsUnlike existing tau overexpression models, C. elegans single-copy expression of tau did not elicit overt pathological phenotypes at baseline. However, strains expressing disease associated PTM-mimetics (T231E and K274/281Q) exhibited reduced touch sensation and morphological abnormalities that increased with age. In addition, the PTM-mimetic mutants lacked the ability to engage mitophagy in response to mitochondrial stress.ConclusionsLimiting the expression of tau results in a genetic model where pathological modifications and age result in evolving phenotypes, which may more closely resemble the normal progression of AD. The finding that disease-associated PTMs suppress compensatory responses to mitochondrial stress provides a new perspective into the pathogenic mechanisms underlying AD.

scholarly journals Drosophila Neuronal Injury Follows a Temporal Sequence of Cellular Events Leading to Degeneration at the Neuromuscular Junction

2015 ◽  
Vol 9s2 ◽  
pp. JEN.S25516 ◽  
Author(s):  
Barron L. Lincoln ◽  
Sahar H. Alabsi ◽  
Nicholas Frendo ◽  
Robert Freund ◽  
Lani C. Keller
Keyword(s):  
Neuromuscular Junction ◽  
Model Organism ◽  
Structural Defects ◽  
Cellular Mechanisms ◽  
Post Injury ◽  
Ubiquitinated Proteins ◽  
Cellular Events ◽  
Molecular Events ◽  
Complex Signaling

Neurodegenerative diseases affect millions of people worldwide, and as the global population ages, there is a critical need to improve our understanding of the molecular and cellular mechanisms that drive neurodegeneration. At the molecular level, neurodegeneration involves the activation of complex signaling pathways that drive the active destruction of neurons and their intracellular components. Here, we use an in vivo motor neuron injury assay to acutely induce neurodegeneration in order to follow the temporal order of events that occur following injury in Drosophila melanogaster. We find that sites of injury can be rapidly identified based on structural defects to the neuronal cytoskeleton that result in disrupted axonal transport. Additionally, the neuromuscular junction accumulates ubiquitinated proteins prior to the neurodegenerative events, occurring at 24 hours post injury. Our data provide insights into the early molecular events that occur during axonal and neuromuscular degeneration in a genetically tractable model organism. Importantly, the mechanisms that mediate neurodegeneration in flies are conserved in humans. Thus, these studies have implications for our understanding of the cellular and molecular events that occur in humans and will facilitate the identification of biomedically relevant targets for future treatments.

scholarly journals Calcineurin homologous proteins regulate the membrane localization and activity of sodium/proton exchangers in C. elegans

2016 ◽  
Vol 310 (3) ◽  
pp. C233-C242 ◽  
Author(s):  
Erik Allman ◽  
Qian Wang ◽  
Rachel L. Walker ◽  
Molly Austen ◽  
Maureen A. Peters ◽  
...  
Keyword(s):  
Genetic Model ◽  
Expression Patterns ◽  
Critical Role ◽  
Model Organism ◽  
Loss Of Function ◽  
Homologous Proteins ◽  
Relative Significance ◽  
C Elegans ◽  
Fluorescent Tags

Calcineurin B homologous proteins (CHP) are N-myristoylated, EF-hand Ca2+-binding proteins that bind to and regulate Na+/H+ exchangers, which occurs through a variety of mechanisms whose relative significance is incompletely understood. Like mammals, Caenorhabditis elegans has three CHP paralogs, but unlike mammals, worms can survive CHP loss-of-function. However, mutants for the CHP ortholog PBO-1 are unfit, and PBO-1 has been shown to be required for proton signaling by the basolateral Na+/H+ exchanger NHX-7 and for proton-coupled intestinal nutrient uptake by the apical Na+/H+ exchanger NHX-2. Here, we have used this genetic model organism to interrogate PBO-1's mechanism of action. Using fluorescent tags to monitor Na+/H+ exchanger trafficking and localization, we found that loss of either PBO-1 binding or activity caused NHX-7 to accumulate in late endosomes/lysosomes. In contrast, NHX-2 was stabilized at the apical membrane by a nonfunctional PBO-1 protein and was only internalized following its complete loss. Additionally, two pbo-1 paralogs were identified, and their expression patterns were analyzed. One of these contributed to the function of the excretory cell, which acts like a kidney in worms, establishing an alternative model for testing the role of this protein in membrane transporter trafficking and regulation. These results lead us to conclude that the role of CHP in Na+/H+ exchanger regulation differs between apical and basolateral transporters. This further emphasizes the importance of proper targeting of Na+/H+ exchangers and the critical role of CHP family proteins in this process.

scholarly journals Optimal strategies for inhibition of protein aggregation

2018 ◽  
Author(s):  
Thomas C. T. Michaels ◽  
Christoph A. Weber ◽  
L. Mahadevan
Keyword(s):  
Protein Aggregation ◽  
Model Organism ◽  
Optimal Strategies ◽  
Secondary Nucleation ◽  
Treatment Protocols ◽  
C Elegans ◽  
Molecular Events ◽  
And Control ◽  
Opening Up ◽  
Viable Treatment

AbstractProtein aggregation has been implicated in many diseases.1-7 Therapeutic strategies for these diseases propose the use of drugs to inhibit specific molecular events during the aggregation process.8-11 However, viable treatment protocols require balancing the efficacy of the drug with its toxicity while accounting for the underlying events of aggregation and inhibition at the molecular level. Here, we combine aggregation kinetics and control theory to determine optimal protocols which prevent protein aggregation via specific reaction pathways. We find that the optimal inhibition of primary and fibril-dependent secondary nucleation require fundamentally different drug administration protocols. We test the efficacy of our approach on experimental data for Amyloid-β aggregation of Alzheimer’s disease in the model organism C. elegans. Our results pose and answer the question of the link between the molecular basis of protein aggregation and optimal strategies for inhibiting it, opening up new avenues for the design of rational therapies to control pathological protein aggregation.

scholarly journals Quantitative Analysis of Drug Efficacy on C. elegans Models for Neuromuscular Diseases

2021 ◽  
Author(s):  
Samuel Sofela ◽  
Sarah Sahloul ◽  
Yong-Ak Song
Keyword(s):  
Drug Screening ◽  
Low Cost ◽  
Neuromuscular Diseases ◽  
Model Organism ◽  
Drug Efficacy ◽  
Two Dimensional ◽  
C Elegans ◽  
Drug Candidates ◽  
High Throughput Drug Screening ◽  
Screening Assays

AbstractCaenorhabditis elegans has emerged as a powerful model organism for drug screening due to its cellular simplicity, genetic amenability and homology to humans combined with its small size and low cost. Currently, high-throughput drug screening assays are mostly based on image-based phenotyping not exploiting key locomotory parameters of this multicellular model with muscles such as its thrashing force, a critical parameter when screening drugs for muscle-related diseases. In this study, we demonstrated the use of a micropillar-based force assay chip in combination with an imaging assay to evaluate the efficacy of various drugs currently used in treatment of neuromuscular diseases. Using this two-dimensional approach, we showed that the force assay was generally more sensitive in measuring efficacy of drug treatment in Duchenne Muscular Dystrophy and Parkinson’s Disease mutant worms as well as partly in Amyotrophic Lateral Sclerosis model. These results underline the potential of our force assay chip in screening of potential drug candidates for the treatment of neuromuscular diseases when combined with an imaging assay in a two-dimensional analysis approach.

scholarly journals A fast and reliable method for monitoring genomic instability in the model organism Caenorhabditis elegans

2021 ◽  
Author(s):  
Merle Marie Nicolai ◽  
Barbara Witt ◽  
Andrea Hartwig ◽  
Tanja Schwerdtle ◽  
Julia Bornhorst
Keyword(s):  
Caenorhabditis Elegans ◽  
Animal Experiments ◽  
Model Organism ◽  
Animal Testing ◽  
C Elegans ◽  
Testing Strategies ◽  
Genotoxic Agents ◽  
Genotoxicity Testing

AbstractThe identification of genotoxic agents and their potential for genotoxic alterations in an organism is crucial for risk assessment and approval procedures of the chemical and pharmaceutical industry. Classically, testing strategies for DNA or chromosomal damage focus on in vitro and in vivo (mainly rodent) investigations. In cell culture systems, the alkaline unwinding (AU) assay is one of the well-established methods for detecting the percentage of double-stranded DNA (dsDNA). By establishing a reliable lysis protocol, and further optimization of the AU assay for the model organism Caenorhabditis elegans (C. elegans), we provided a new tool for genotoxicity testing in the niche between in vitro and rodent experiments. The method is intended to complement existing testing strategies by a multicellular organism, which allows higher predictability of genotoxic potential compared to in vitro cell line or bacterial investigations, before utilizing in vivo (rodent) investigations. This also allows working within the 3R concept (reduction, refinement, and replacement of animal experiments), by reducing and possibly replacing animal testing. Validation with known genotoxic agents (bleomycin (BLM) and tert-butyl hydroperoxide (tBOOH)) proved the method to be meaningful, reproducible, and feasible for high-throughput genotoxicity testing, and especially preliminary screening.

scholarly journals Chromatin accessibility dynamics reveal novel functional enhancers in C. elegans

2016 ◽  
Author(s):  
Aaron C. Daugherty ◽  
Robin Yeo ◽  
Jason D. Buenrostro ◽  
William J. Greenleaf ◽  
Anshul Kundaje ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Developmental Stages ◽  
Model Organism ◽  
High Sensitivity ◽  
Chromatin Accessibility ◽  
Chromatin Dynamics ◽  
C Elegans ◽  
Crucial Component ◽  
Organismal Development

AbstractChromatin accessibility, a crucial component of genome regulation, has primarily been studied in homogeneous and simple systems, such as isolated cell populations or early-development models. Whether chromatin accessibility can be assessed in complex, dynamic systems in vivo with high sensitivity remains largely unexplored. In this study, we use ATAC-seq to identify chromatin accessibility changes in a whole animal, the model organism C. elegans, from embryogenesis to adulthood. Chromatin accessibility changes between developmental stages are highly reproducible, recapitulate histone modification changes, and reveal key regulatory aspects of the epigenomic landscape throughout organismal development. We find that over 5,000 distal non-coding regions exhibit dynamic changes in chromatin accessibility between developmental stages, and could thereby represent putative enhancers. When tested in vivo, several of these putative enhancers indeed drive novel cell-type-and temporal-specific patterns of expression. Finally, by integrating transcription factor binding motifs in a machine learning framework, we identify EOR-1 as a unique transcription factor that may regulate chromatin dynamics during development. Our study provides a unique resource for C. elegans, a system in which the prevalence and importance of enhancers remains poorly characterized, and demonstrates the power of using whole organism chromatin accessibility to identify novel regulatory regions in complex systems.

scholarly journals Detecting changes in the Caenorhabditis elegans intestinal environment using an engineered bacterial biosensor

2019 ◽  
Author(s):  
Jack W. Rutter ◽  
Tanel Ozdemir ◽  
Leonor M. Quintaneiro ◽  
Geraint Thomas ◽  
Filipe Cabreiro ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Rational Design ◽  
Model Organism ◽  
Bacterial Biosensor ◽  
Intestinal Environment ◽  
C Elegans ◽  
Ideal Candidate ◽  
Diagnostic Applications

AbstractCaenorhabditis elegans has become a key model organism within biology. In particular, the transparent gut, rapid growing time and ability to create a defined gut microbiota make it an ideal candidate organism for understanding and engineering the host microbiota. Here we present the development of an experimental model which can be used to characterise whole-cell bacterial biosensors in vivo. A dual-plasmid sensor system responding to isopropyl β-D-1-thiogalactopyranoside was developed and fully characterised in vitro. Subsequently, we show the sensor was capable of detecting and reporting on changes in the intestinal environment of C. elegans after introducing exogenous inducer into the environment. The protocols presented here may be used for aiding the rational design of engineered bacterial circuits, primarily for diagnostic applications. In addition, the model system may serve to reduce the use of current animal models and aid in the exploration of complex questions within general nematode and host-microbe biology.

Sign in / Sign up

Export Citation Format

Share Document