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Guo A, Wu Q, Yan X, Chen K, Liu Y, Liang D, Yang Y, Luo Q, Xiong M, Yu Y, Fei E, Chen F. Differential roles of lysosomal cholesterol transporters in the development of C. elegans NMJs. Life Sci Alliance 2024; 7:e202402584. [PMID: 39084875 PMCID: PMC11291935 DOI: 10.26508/lsa.202402584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 07/21/2024] [Accepted: 07/22/2024] [Indexed: 08/02/2024] Open
Abstract
Cholesterol homeostasis in neurons is critical for synapse formation and maintenance. Neurons with impaired cholesterol uptake undergo progressive synapse loss and eventual degeneration. To investigate the molecular mechanisms of neuronal cholesterol homeostasis and its role during synapse development, we studied motor neurons of Caenorhabditis elegans because these neurons rely on dietary cholesterol. Combining lipidomic analysis, we discovered that NCR-1, a lysosomal cholesterol transporter, promotes cholesterol absorption and synapse development. Loss of ncr-1 causes smaller synapses, and low cholesterol exacerbates the deficits. Moreover, NCR-1 deficiency hinders the increase in synapses under high cholesterol. Unexpectedly, NCR-2, the NCR-1 homolog, increases the use of cholesterol and sphingomyelins and impedes synapse formation. NCR-2 deficiency causes an increase in synapses regardless of cholesterol concentration. Inhibiting the degradation or synthesis of sphingomyelins can induce or suppress the synaptic phenotypes in ncr-2 mutants. Our findings indicate that neuronal cholesterol homeostasis is differentially controlled by two lysosomal cholesterol transporters and highlight the importance of neuronal cholesterol homeostasis in synapse development.
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Affiliation(s)
- Amin Guo
- https://ror.org/042v6xz23 School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Qi Wu
- https://ror.org/042v6xz23 School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Xin Yan
- https://ror.org/042v6xz23 School of Life Sciences, Nanchang University, Nanchang, China
| | - Kanghua Chen
- https://ror.org/042v6xz23 School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yuxiang Liu
- https://ror.org/042v6xz23 School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Dingfa Liang
- https://ror.org/042v6xz23 Queen Mary School of Nanchang University, Jiangxi Medical College, Nanchang, China
| | - Yuxiao Yang
- https://ror.org/042v6xz23 School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Qunfeng Luo
- https://ror.org/042v6xz23 School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Mingtao Xiong
- https://ror.org/042v6xz23 Institute of Biomedical Innovation, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yong Yu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, China
| | - Erkang Fei
- https://ror.org/042v6xz23 Institute of Biomedical Innovation, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Fei Chen
- https://ror.org/042v6xz23 School of Basic Medical Sciences, Jiangxi Medical College, Nanchang University, Nanchang, China
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2
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Kamal M, Mukherjee S, Joshi B, Sindhu ZUD, Wangchuk P, Haider S, Ahmed N, Talukder MH, Geary TG, Yadav AK. Model nematodes as a practical innovation to promote high throughput screening of natural products for anthelmintics discovery in South Asia: Current challenges, proposed practical and conceptual solutions. Mol Biochem Parasitol 2023; 256:111594. [PMID: 37730126 DOI: 10.1016/j.molbiopara.2023.111594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 08/27/2023] [Accepted: 09/12/2023] [Indexed: 09/22/2023]
Abstract
With the increasing prevalence of anthelmintic resistance in animals recorded globally, and the threat of resistance in human helminths, the need for novel anthelmintic drugs is greater than ever. Most research aimed at discovering novel anthelmintic leads relies on high throughput screening (HTS) of large libraries of synthetic small molecules in industrial and academic settings in developed countries, even though it is the tropical countries that are most plagued by helminth infections. Tropical countries, however, have the advantage of possessing a rich flora that may yield natural products (NP) with promising anthelmintic activity. Focusing on South Asia, which produces one of the world's highest research outputs in NP and NP-based anthelmintic discovery, we find that limited basic research and funding, a lack of awareness of the utility of model organisms, poor industry-academia partnerships and lack of technological innovations greatly limit anthelmintics research in the region. Here we propose that utilizing model organisms including the free-living nematode Caenorhabditis elegans, that can potentially allow rapid target identification of novel anthelmintics, and Oscheius tipulae, a closely related, free-living nematode which is found abundantly in soil in hotter temperatures, could be a much-needed innovation that can enable cost-effective and efficient HTS of NPs for discovering compounds with anthelmintic/antiparasitic potential in South Asia and other tropical regions that historically have devoted limited funding for such research. Additionally, increased collaborations at the national, regional and international level between parasitologists and pharmacologists/ethnobotanists, setting up government-industry-academia partnerships to fund academic research, creating a centralized, regional collection of plant extracts or purified NPs as a dereplication strategy and HTS library, and holding regional C. elegans/O. tipulae-based anthelmintics workshops and conferences to share knowledge and resources regarding model organisms may collectively promote and foster a NP-based anthelmintics landscape in South Asia and beyond.
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Affiliation(s)
- Muntasir Kamal
- Department of Molecular Genetics, University of Toronto, Toronto, Canada.
| | - Suprabhat Mukherjee
- Department of Animal Science, Kazi Nazrul University, Asansol 713340, West Bengal, India
| | - Bishnu Joshi
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Zia-Ud-Din Sindhu
- Department of Parasitology, University of Agriculture Faisalabad, Pakistan
| | - Phurpa Wangchuk
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns Campus, QLD 4878, Australia
| | | | - Nurnabi Ahmed
- Department of Parasitology, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | | | - Timothy G Geary
- Institute of Parasitology, McGill University, Montreal, Canada; School of Biological Sciences, Queen's University-Belfast, Belfast, NI, UK
| | - Arun K Yadav
- Department of Zoology, North-Eastern Hill University, Shillong 793022, India
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Wang J, Saul J, Nikonorova IA, Cruz CN, Power KM, Nguyen KC, Hall DH, Barr MM. Ciliary intrinsic mechanisms regulate dynamic ciliary extracellular vesicle release from sensory neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.01.565151. [PMID: 37961114 PMCID: PMC10635059 DOI: 10.1101/2023.11.01.565151] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Cilia-derived extracellular vesicles (EVs) contain signaling proteins and act in intercellular communication. Polycystin-2 (PKD-2), a transient receptor potential channel, is a conserved ciliary EVs cargo. Caenorhabditis elegans serves as a model for studying ciliary EV biogenesis and function. C. elegans males release EVs in a mechanically-induced manner and deposit PKD-2-labeled EVs onto the hermaphrodite vulva during mating, suggesting an active release process. Here, we study the dynamics of ciliary EV release using time-lapse imaging and find that cilia can sustain the release of PKD-2-labeled EVs for a two-hour duration. Intriguingly, this extended release doesn't require neuronal synaptic transmission. Instead, ciliary intrinsic mechanisms regulate PKD-2 ciliary membrane replenishment and dynamic EV release. The ciliary kinesin-3 motor KLP-6 is necessary for both initial and extended ciliary EV release, while the transition zone protein NPHP-4 is required only for sustained EV release. The dihydroceramide desaturase DEGS1/2 ortholog TTM-5 is highly expressed in the EV-releasing sensory neurons, localizes to cilia, and is required for sustained but not initial ciliary EV release, implicating ceramide in ciliary ectocytosis. The study offers a comprehensive portrait of real-time ciliary EV release, and mechanisms supporting cilia as proficient EV release platforms.
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Affiliation(s)
- Juan Wang
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Josh Saul
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Inna A. Nikonorova
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Carlos Nava Cruz
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Kaiden M. Power
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | - Ken C. Nguyen
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - David H. Hall
- Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Maureen M. Barr
- Department of Genetics and Human Genetics Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
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4
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Kamal M, Tokmakjian L, Knox J, Han D, Moshiri H, Magomedova L, Nguyen KCQ, Zheng H, Burns AR, Cooke B, Lacoste J, Yeo M, Hall DH, Cummins CL, Roy PJ. PGP-14 establishes a polar lipid permeability barrier within the C. elegans pharyngeal cuticle. PLoS Genet 2023; 19:e1011008. [PMID: 37930961 PMCID: PMC10653525 DOI: 10.1371/journal.pgen.1011008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 11/16/2023] [Accepted: 10/05/2023] [Indexed: 11/08/2023] Open
Abstract
The cuticles of ecdysozoan animals are barriers to material loss and xenobiotic insult. Key to this barrier is lipid content, the establishment of which is poorly understood. Here, we show that the p-glycoprotein PGP-14 functions coincidently with the sphingomyelin synthase SMS-5 to establish a polar lipid barrier within the pharyngeal cuticle of the nematode C. elegans. We show that PGP-14 and SMS-5 are coincidentally expressed in the epithelium that surrounds the anterior pharyngeal cuticle where PGP-14 localizes to the apical membrane. pgp-14 and sms-5 also peak in expression at the time of new cuticle synthesis. Loss of PGP-14 and SMS-5 dramatically reduces pharyngeal cuticle staining by Nile Red, a key marker of polar lipids, and coincidently alters the nematode's response to a wide-range of xenobiotics. We infer that PGP-14 exports polar lipids into the developing pharyngeal cuticle in an SMS-5-dependent manner to safeguard the nematode from environmental insult.
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Affiliation(s)
- Muntasir Kamal
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Levon Tokmakjian
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Jessica Knox
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Duhyun Han
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Houtan Moshiri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Lilia Magomedova
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Ken CQ Nguyen
- Department of Neuroscience, Albert Einstein College of Medicine, New York, New York, United States of America
| | - Hong Zheng
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Andrew R. Burns
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Brittany Cooke
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Jessica Lacoste
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - May Yeo
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - David H. Hall
- Department of Neuroscience, Albert Einstein College of Medicine, New York, New York, United States of America
| | - Carolyn L. Cummins
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
| | - Peter J. Roy
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
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5
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Kamal M, Tokmakjian L, Knox J, Mastrangelo P, Ji J, Cai H, Wojciechowski JW, Hughes MP, Takács K, Chu X, Pei J, Grolmusz V, Kotulska M, Forman-Kay JD, Roy PJ. A spatiotemporal reconstruction of the C. elegans pharyngeal cuticle reveals a structure rich in phase-separating proteins. eLife 2022; 11:e79396. [PMID: 36259463 PMCID: PMC9629831 DOI: 10.7554/elife.79396] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 10/11/2022] [Indexed: 11/19/2022] Open
Abstract
How the cuticles of the roughly 4.5 million species of ecdysozoan animals are constructed is not well understood. Here, we systematically mine gene expression datasets to uncover the spatiotemporal blueprint for how the chitin-based pharyngeal cuticle of the nematode Caenorhabditis elegans is built. We demonstrate that the blueprint correctly predicts expression patterns and functional relevance to cuticle development. We find that as larvae prepare to molt, catabolic enzymes are upregulated and the genes that encode chitin synthase, chitin cross-linkers, and homologs of amyloid regulators subsequently peak in expression. Forty-eight percent of the gene products secreted during the molt are predicted to be intrinsically disordered proteins (IDPs), many of which belong to four distinct families whose transcripts are expressed in overlapping waves. These include the IDPAs, IDPBs, and IDPCs, which are introduced for the first time here. All four families have sequence properties that drive phase separation and we demonstrate phase separation for one exemplar in vitro. This systematic analysis represents the first blueprint for cuticle construction and highlights the massive contribution that phase-separating materials make to the structure.
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Affiliation(s)
- Muntasir Kamal
- Department of Molecular Genetics, University of TorontoTorontoCanada
- The Donnelly Centre for Cellular and Biomolecular Research, University of TorontoTorontoCanada
| | - Levon Tokmakjian
- The Donnelly Centre for Cellular and Biomolecular Research, University of TorontoTorontoCanada
- Department of Pharmacology and Toxicology, University of TorontoTorontoCanada
| | - Jessica Knox
- Department of Molecular Genetics, University of TorontoTorontoCanada
- The Donnelly Centre for Cellular and Biomolecular Research, University of TorontoTorontoCanada
| | - Peter Mastrangelo
- Department of Molecular Genetics, University of TorontoTorontoCanada
- The Donnelly Centre for Cellular and Biomolecular Research, University of TorontoTorontoCanada
| | - Jingxiu Ji
- Department of Molecular Genetics, University of TorontoTorontoCanada
- The Donnelly Centre for Cellular and Biomolecular Research, University of TorontoTorontoCanada
| | - Hao Cai
- Molecular Medicine Program, The Hospital for Sick ChildrenTorontoCanada
| | - Jakub W Wojciechowski
- Wroclaw University of Science and Technology, Faculty of Fundamental Problems of Technology, Department of Biomedical EngineeringWroclawPoland
| | - Michael P Hughes
- Department of Cell and Molecular Biology, St. Jude Children’s Research HospitalMemphisUnited States
| | - Kristóf Takács
- PIT Bioinformatics Group, Institute of Mathematics, Eötvös UniversityBudapestHungary
| | - Xiaoquan Chu
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking UniversityBeijingChina
| | - Jianfeng Pei
- Department of Computer Science and Technology, Tsinghua UniversityBeijingChina
| | - Vince Grolmusz
- PIT Bioinformatics Group, Institute of Mathematics, Eötvös UniversityBudapestHungary
| | - Malgorzata Kotulska
- Wroclaw University of Science and Technology, Faculty of Fundamental Problems of Technology, Department of Biomedical EngineeringWroclawPoland
| | - Julie Deborah Forman-Kay
- Molecular Medicine Program, The Hospital for Sick ChildrenTorontoCanada
- Department of Biochemistry, University of TorontoTorontoCanada
| | - Peter J Roy
- Department of Molecular Genetics, University of TorontoTorontoCanada
- The Donnelly Centre for Cellular and Biomolecular Research, University of TorontoTorontoCanada
- Department of Pharmacology and Toxicology, University of TorontoTorontoCanada
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6
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High-content approaches to anthelmintic drug screening. Trends Parasitol 2021; 37:780-789. [PMID: 34092518 DOI: 10.1016/j.pt.2021.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/03/2021] [Accepted: 05/11/2021] [Indexed: 11/23/2022]
Abstract
Most anthelmintics were discovered through in vivo screens using animal models of infection. Developing in vitro assays for parasitic worms presents several challenges. The lack of in vitro life cycle culture protocols requires harvesting worms from vertebrate hosts or vectors, limiting assay throughput. Once worms are removed from the host environment, established anthelmintics often show no obvious phenotype - raising concerns about the predictive value of many in vitro assays. However, with recent progress in understanding how anthelmintics subvert host-parasite interactions, and breakthroughs in high-content imaging and machine learning, in vitro assays have the potential to discern subtle cryptic parasite phenotypes. These may prove better endpoints than conventional in vitro viability assays.
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7
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Easy ultrastructural insight into the internal morphology of biological specimens by Atomic Force Microscopy. Sci Rep 2021; 11:10214. [PMID: 33986350 PMCID: PMC8119718 DOI: 10.1038/s41598-021-89633-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 04/27/2021] [Indexed: 02/08/2023] Open
Abstract
As a topographical technique, Atomic Force Microscopy (AFM) needs to establish direct interactions between a given sample and the measurement probe in order to create imaging information. The elucidation of internal features of organisms, tissues and cells by AFM has therefore been a challenging process in the past. To overcome this hindrance, simple and fast embedding, sectioning and dehydration techniques are presented, allowing the easy access to the internal morphology of virtually any organism, tissue or cell by AFM. The study at hand shows the applicability of the proposed protocol to exemplary biological samples, the resolution currently allowed by the approach as well as advantages and shortcomings compared to classical ultrastructural microscopic techniques like electron microscopy. The presented cheap, facile, fast and non-toxic experimental protocol might introduce AFM as a universal tool for the elucidation of internal ultrastructural detail of virtually any given organism, tissue or cell.
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8
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Giunti S, Andersen N, Rayes D, De Rosa MJ. Drug discovery: Insights from the invertebrate Caenorhabditis elegans. Pharmacol Res Perspect 2021; 9:e00721. [PMID: 33641258 PMCID: PMC7916527 DOI: 10.1002/prp2.721] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 01/06/2021] [Indexed: 12/18/2022] Open
Abstract
Therapeutic drug development is a long, expensive, and complex process that usually takes 12-15 years. In the early phases of drug discovery, in particular, there is a growing need for animal models that ensure the reduction in both cost and time. Caenorhabditis elegans has been traditionally used to address fundamental aspects of key biological processes, such as apoptosis, aging, and gene expression regulation. During the last decade, with the advent of large-scale platforms for screenings, this invertebrate has also emerged as an essential tool in the pharmaceutical research industry to identify novel drugs and drug targets. In this review, we discuss the reasons why C. elegans has been positioned as an outstanding cost-effective option for drug discovery, highlighting both the advantages and drawbacks of this model. Particular attention is paid to the suitability of this nematode in large-scale genetic and pharmacological screenings. High-throughput screenings in C. elegans have indeed contributed to the breakthrough of a wide variety of candidate compounds involved in extensive fields including neurodegeneration, pathogen infections and metabolic disorders. The versatility of this nematode, which enables its instrumentation as a model of human diseases, is another attribute also herein underscored. As illustrative examples, we discuss the utility of C. elegans models of both human neurodegenerative diseases and parasitic nematodes in the drug discovery industry. Summing up, this review aims to demonstrate the impact of C. elegans models on the drug discovery pipeline.
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Affiliation(s)
- Sebastián Giunti
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS‐CONICETBahía BlancaArgentina
- Dpto de Biología, Bioquímica y FarmaciaUniversidad Nacional del SurBahía BlancaArgentina
| | - Natalia Andersen
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS‐CONICETBahía BlancaArgentina
- Dpto de Biología, Bioquímica y FarmaciaUniversidad Nacional del SurBahía BlancaArgentina
| | - Diego Rayes
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS‐CONICETBahía BlancaArgentina
- Dpto de Biología, Bioquímica y FarmaciaUniversidad Nacional del SurBahía BlancaArgentina
| | - María José De Rosa
- Instituto de Investigaciones Bioquímicas de Bahía Blanca (INIBIBB) CCT UNS‐CONICETBahía BlancaArgentina
- Dpto de Biología, Bioquímica y FarmaciaUniversidad Nacional del SurBahía BlancaArgentina
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9
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Abstract
The nematode worm Caenorhabditis elegans is a model for deciphering the neural circuitry that transmits information from sensory organ to muscle tissue. It is also studied for disentangling the characteristics of the network, the efficiency of its design, and for testing theoretical models on how information is encoded. For this study, the efficiency of the synaptic connections was studied by testing the robustness of the neural network. A randomization test of robustness was applied to previously computed neural modules of the pharynx of C. elegans. The results support robustness as a reason for the observed over connectiveness across the pharyngeal system. In addition, rare events of single-neuron loss may expectedly lead to loss of function in a neural system.
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Affiliation(s)
- Robert Friedman
- Department of Biological Sciences, University of South Carolina, Columbia, USA
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10
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Galford KF, Jose AM. The FDA-approved drugs ticlopidine, sertaconazole, and dexlansoprazole can cause morphological changes in C. elegans. CHEMOSPHERE 2020; 261:127756. [PMID: 32731027 PMCID: PMC7606649 DOI: 10.1016/j.chemosphere.2020.127756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 06/11/2023]
Abstract
Urgent need for treatments limit studies of therapeutic drugs before approval by regulatory agencies. Analyses of drugs after approval can therefore improve our understanding of their mechanism of action and enable better therapies. We screened a library of 1443 Food and Drug Administration (FDA)-approved drugs using a simple assay in the nematode C. elegans and found three compounds that caused morphological changes. While the anticoagulant ticlopidine and the antifungal sertaconazole caused both accumulations that resulted in distinct distortions of pharyngeal anatomy and lethality upon acute exposure, the proton-pump inhibitor dexlansoprazole caused molting defects and required exposure during larval development. Such easily detectable defects in a powerful genetic model system advocate the continued exploration of current medicines using a variety of model organisms to better understand drugs already prescribed to millions of patients.
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Affiliation(s)
- Kyle F Galford
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Antony M Jose
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA.
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11
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Suzuki Y, Kikuchi K, Numayama-Tsuruta K, Ishikawa T. How do Caenorhabditis elegans worms survive in highly viscous habitats? J Exp Biol 2020; 223:jeb224691. [PMID: 32587072 DOI: 10.1242/jeb.224691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 06/21/2020] [Indexed: 11/20/2022]
Abstract
The nematode Caenorhabditis elegans is a filter feeder that lives in various viscous habitats such as soil, the intestines of slugs, and rotting materials such as fruits and stems. Caenorhabditis elegans draws in suspensions of bacteria and separates bacteria from water using the pharyngeal pump. Although these worms often live in highly viscous habitats, it is still unclear how they survive in these environments by eating bacteria. In this study, we investigated the effects of suspension viscosity on the survival rate of malnourished worms by combining live imaging and scaling analyses. We found that survival rate decreased with increases in viscosity because the high viscosity suppressed the amount of food ingested. The same tendency was found in two feeding-defective mutants, eat-6(ad467) and eat-6(ad997). We also found that the high viscosity weakened pump function, but the velocities in the pharynx were not zero, even in the most viscous suspensions. Finally, we estimated the amount of ingested food using scaling analyses, which provided a master curve of the experimental survival rates. These results illustrate that the survival rate of C. elegans worms is strongly dependent on the ingested bacteria per unit time associated with physical environments, such as the viscosity of food suspensions and the cell density of bacteria. The pump function of the C. elegans pharynx is not completely lost even in fluids that have 105 times higher viscosity than water, which may contribute to their ability to survive around the world in highly viscous environments.
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Affiliation(s)
- Yuki Suzuki
- Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai, Miyagi 980-8579, Japan
| | - Kenji Kikuchi
- Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai, Miyagi 980-8579, Japan
- Graduate School of Biomedical Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai, Miyagi 980-8579, Japan
| | - Keiko Numayama-Tsuruta
- Graduate School of Biomedical Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai, Miyagi 980-8579, Japan
| | - Takuji Ishikawa
- Department of Finemechanics, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai, Miyagi 980-8579, Japan
- Graduate School of Biomedical Engineering, Tohoku University, 6-6-01 Aramaki Aza Aoba, Sendai, Miyagi 980-8579, Japan
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Otarigho B, Aballay A. Cholesterol Regulates Innate Immunity via Nuclear Hormone Receptor NHR-8. iScience 2020; 23:101068. [PMID: 32361270 PMCID: PMC7195545 DOI: 10.1016/j.isci.2020.101068] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/09/2020] [Accepted: 04/13/2020] [Indexed: 02/06/2023] Open
Abstract
Cholesterol is an essential nutrient for the function of diverse biological processes and for steroid biosynthesis across metazoans. However, the role of cholesterol in immune function remains understudied. Using the nematode Caenorhabditis elegans, which depends on the external environment for cholesterol, we studied the relationship between cholesterol and innate immunity. We found that the transporter CHUP-1 is required for the effect of cholesterol in the development of innate immunity and that the cholesterol-mediated immune response requires the nuclear hormone receptor NHR-8. Cholesterol acts through NHR-8 to transcriptionally regulate immune genes that are controlled by conserved immune pathways, including a p38/PMK-1 MAPK pathway, a DAF-2/DAF-16 insulin pathway, and an Nrf/SKN-1 pathway. Our results indicate that cholesterol plays a key role in the activation of conserved microbicidal pathways that are essential for survival against bacterial infections.
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Affiliation(s)
- Benson Otarigho
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Alejandro Aballay
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA.
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