C. elegans models of neuromuscular diseases expedite translational research

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.

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

Scientific Reports ◽

10.1038/s41598-019-56498-5 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

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.

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In Vivo Production of RNA Aptamers and Nanoparticles: Problems and Prospects

Molecules ◽

10.3390/molecules26051422 ◽

2021 ◽

Vol 26 (5) ◽

pp. 1422

Author(s):

Ousama Al Shanaa ◽

Andrey Rumyantsev ◽

Elena Sambuk ◽

Marina Padkina

Keyword(s):

Saccharomyces Cerevisiae ◽

Large Scale ◽

Potential Model ◽

Model Organism ◽

Rna Aptamers ◽

Early Stages ◽

Near Future

RNA aptamers are becoming increasingly attractive due to their superior properties. This review discusses the early stages of aptamer research, the main developments in this area, and the latest technologies being developed. The review also highlights the advantages of RNA aptamers in comparison to antibodies, considering the great potential of RNA aptamers and their applications in the near future. In addition, it is shown how RNA aptamers can form endless 3-D structures, giving rise to various structural and functional possibilities. Special attention is paid to the Mango, Spinach and Broccoli fluorescent RNA aptamers, and the advantages of split RNA aptamers are discussed. The review focuses on the importance of creating a platform for the synthesis of RNA nanoparticles in vivo and examines yeast, namely Saccharomyces cerevisiae, as a potential model organism for the production of RNA nanoparticles on a large scale.

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Caenorhabditis elegans as an in vivo Model to Assess Amphetamine Tolerance

Brain Behavior and Evolution ◽

10.1159/000514858 ◽

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.

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

10.1101/2020.02.12.946004 ◽

2020 ◽

Cited By ~ 1

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.

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

AJP Cell Physiology ◽

10.1152/ajpcell.00291.2015 ◽

2016 ◽

Vol 310 (3) ◽

pp. C233-C242 ◽

Cited By ~ 4

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.

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Motor Chip: A Comparative Genomic Hybridization Microarray for Copy-Number Mutations in 245 Neuromuscular Disorders

Clinical Chemistry ◽

10.1373/clinchem.2011.168898 ◽

2011 ◽

Vol 57 (11) ◽

pp. 1584-1596 ◽

Cited By ~ 30

Author(s):

Giulio Piluso ◽

Manuela Dionisi ◽

Francesca Del Vecchio Blanco ◽

Annalaura Torella ◽

Stefania Aurino ◽

...

Keyword(s):

Comparative Genomic Hybridization ◽

Copy Number ◽

Neuromuscular Disorders ◽

Neuromuscular Diseases ◽

Copy Number Variations ◽

Comparative Genomic ◽

Specific Gene ◽

Disease Genes ◽

Genomic Hybridization ◽

Gene Coverage

BACKGROUND Array-based comparative genomic hybridization (aCGH) is a reference high-throughput technology for detecting large pathogenic or polymorphic copy-number variations in the human genome; however, a number of quantitative monogenic mutations, such as smaller heterozygous deletions or duplications, are usually missed in most disease genes when proper multiplex ligation-dependent probe assays are not performed. METHODS We developed the Motor Chip, a customized CGH array with exonic coverage of 245 genes involved in neuromuscular disorders (NMDs), as well as 180 candidate disease genes. We analyzed DNA samples from 26 patients with known deletions or duplications in NMDs, 11 patients with partial molecular diagnoses, and 19 patients with a clinical diagnosis alone. RESULTS The Motor Chip efficiently confirmed and refined the copy-number mutations in all of the characterized patients, even when only a single exon was involved. In noncharacterized or partially characterized patients, we found deletions in the SETX (senataxin), SGCG [sarcoglycan, gamma (35kDa dystrophin-associated glycoprotein)], and LAMA2 (laminin, alpha 2) genes, as well as duplications involving LAMA2 and the DYSF [dysferlin, limb girdle muscular dystrophy 2B (autosomal recessive)] locus. CONCLUSIONS The combination of exon-specific gene coverage and optimized platform and probe selection makes the Motor Chip a complementary tool for molecular diagnosis and gene investigation in neuromuscular diseases.

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Caenorhabditis elegans, a Host to Investigate the Probiotic Properties of Beneficial Microorganisms

Frontiers in Nutrition ◽

10.3389/fnut.2020.00135 ◽

2020 ◽

Vol 7 ◽

Author(s):

Cyril Poupet ◽

Christophe Chassard ◽

Adrien Nivoliez ◽

Stéphanie Bornes

Keyword(s):

Caenorhabditis Elegans ◽

High Throughput Screening ◽

Large Scale ◽

Molecular Mechanisms ◽

Probiotic Properties ◽

C Elegans ◽

Probiotic Potential ◽

Challenges And Opportunities ◽

Future Challenges

Caenorhabditis elegans, a non-parasitic nematode emerges as a relevant and powerful candidate as an in vivo model for microorganisms-microorganisms and microorganisms-host interactions studies. Experiments have demonstrated the probiotic potential of bacteria since they can provide to the worm a longer lifespan, an increased resistance to pathogens and to oxidative or heat stresses. Probiotics are used to prevent or treat microbiota dysbiosis and associated pathologies but the molecular mechanisms underlying their capacities are still unknown. Beyond safety and healthy aspects of probiotics, C. elegans represents a powerful way to design large-scale studies to explore transkingdom interactions and to solve questioning about the molecular aspect of these interactions. Future challenges and opportunities would be to validate C. elegans as an in vivo tool for high-throughput screening of microorganisms for their potential probiotic use on human health and to enlarge the panels of microorganisms studied as well as the human diseases investigated.

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

10.1101/2021.01.21.427562 ◽

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.

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

Archives of Toxicology ◽

10.1007/s00204-021-03144-7 ◽

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.

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Chromatin accessibility dynamics reveal novel functional enhancers in C. elegans

10.1101/088732 ◽

2016 ◽

Cited By ~ 2

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.

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