1
|
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] [What about the content of this article? (0)] [Affiliation(s)] [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.
Collapse
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
| |
Collapse
|
2
|
Burns AR, Baker RJ, Kitner M, Knox J, Cooke B, Volpatti JR, Vaidya AS, Puumala E, Palmeira BM, Redman EM, Snider J, Marwah S, Chung SW, MacDonald MH, Tiefenbach J, Hu C, Xiao Q, Finney CAM, Krause HM, MacParland SA, Stagljar I, Gilleard JS, Cowen LE, Meyer SLF, Cutler SR, Dowling JJ, Lautens M, Zasada I, Roy PJ. Selective control of parasitic nematodes using bioactivated nematicides. Nature 2023:10.1038/s41586-023-06105-5. [PMID: 37225985 DOI: 10.1038/s41586-023-06105-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 04/20/2023] [Indexed: 05/26/2023]
Abstract
Parasitic nematodes are a major threat to global food security, particularly as the world amasses 10 billion people amid limited arable land1-4. Most traditional nematicides have been banned owing to poor nematode selectivity, leaving farmers with inadequate means of pest control4-12. Here we use the model nematode Caenorhabditis elegans to identify a family of selective imidazothiazole nematicides, called selectivins, that undergo cytochrome-p450-mediated bioactivation in nematodes. At low parts-per-million concentrations, selectivins perform comparably well with commercial nematicides to control root infection by Meloidogyne incognita, a highly destructive plant-parasitic nematode. Tests against numerous phylogenetically diverse non-target systems demonstrate that selectivins are more nematode-selective than most marketed nematicides. Selectivins are first-in-class bioactivated nematode controls that provide efficacy and nematode selectivity.
Collapse
Affiliation(s)
- Andrew R Burns
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
| | - Rachel J Baker
- Davenport Research Laboratories, Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Megan Kitner
- USDA-ARS Horticultural Crops Research Laboratory, Corvallis, OR, USA
| | - Jessica Knox
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Brittany Cooke
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Jonathan R Volpatti
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Aditya S Vaidya
- Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, USA
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, USA
| | - Emily Puumala
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Bruna M Palmeira
- Department of Comparative Biology and Experimental Medicine, Host-Parasite Interactions Program, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Elizabeth M Redman
- Department of Comparative Biology and Experimental Medicine, Host-Parasite Interactions Program, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jamie Snider
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Sagar Marwah
- Ajmera Transplant Centre, Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology and Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Sai W Chung
- Ajmera Transplant Centre, Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology and Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Margaret H MacDonald
- USDA-ARS Mycology and Nematology Genetic Diversity and Biology Laboratory, Beltsville Agricultural Research Center, Beltsville, MD, USA
| | - Jens Tiefenbach
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Chun Hu
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Qi Xiao
- Department of Biological Sciences, Host Parasite Interactions Program, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
| | - Constance A M Finney
- Department of Biological Sciences, Host Parasite Interactions Program, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
| | - Henry M Krause
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Sonya A MacParland
- Ajmera Transplant Centre, Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology and Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Igor Stagljar
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Mediterranean Institute for Life Sciences, Split, Croatia
| | - John S Gilleard
- Department of Comparative Biology and Experimental Medicine, Host-Parasite Interactions Program, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Susan L F Meyer
- USDA-ARS Mycology and Nematology Genetic Diversity and Biology Laboratory, Beltsville Agricultural Research Center, Beltsville, MD, USA
| | - Sean R Cutler
- Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, USA
- Department of Botany and Plant Sciences, University of California, Riverside, Riverside, CA, USA
| | - James J Dowling
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mark Lautens
- Davenport Research Laboratories, Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Inga Zasada
- USDA-ARS Horticultural Crops Research Laboratory, Corvallis, OR, USA
| | - Peter J Roy
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada.
| |
Collapse
|
3
|
Harrington S, Pyche J, Burns AR, Spalholz T, Ryan KT, Baker RJ, Ching J, Rufener L, Lautens M, Kulke D, Vernudachi A, Zamanian M, Deuther-Conrad W, Brust P, Roy PJ. Nemacol is a small molecule inhibitor of C. elegans vesicular acetylcholine transporter with anthelmintic potential. Nat Commun 2023; 14:1816. [PMID: 37002199 PMCID: PMC10066365 DOI: 10.1038/s41467-023-37452-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 03/17/2023] [Indexed: 04/03/2023] Open
Abstract
Nematode parasites of humans and livestock pose a significant burden to human health, economic development, and food security. Anthelmintic drug resistance is widespread among parasites of livestock and many nematode parasites of humans lack effective treatments. Here, we present a nitrophenyl-piperazine scaffold that induces motor defects rapidly in the model nematode Caenorhabditis elegans. We call this scaffold Nemacol and show that it inhibits the vesicular acetylcholine transporter (VAChT), a target recognized by commercial animal and crop health groups as a viable anthelmintic target. We demonstrate that it is possible to create Nemacol analogs that maintain potent in vivo activity whilst lowering their affinity to the mammalian VAChT 10-fold. We also show that Nemacol enhances the ability of the anthelmintic Ivermectin to paralyze C. elegans and the ruminant nematode parasite Haemonchus contortus. Hence, Nemacol represents a promising new anthelmintic scaffold that acts through a validated anthelmintic target.
Collapse
Affiliation(s)
- Sean Harrington
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Jacob Pyche
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Andrew R Burns
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Tina Spalholz
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318, Leipzig, Germany
| | - Kaetlyn T Ryan
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Rachel J Baker
- The Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
| | - Justin Ching
- The Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
| | - Lucien Rufener
- INVENesis Sàrl, Route de Neuchâtel 15A, 2072, St Blaise (NE), Switzerland
| | - Mark Lautens
- The Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
| | - Daniel Kulke
- Research Parasiticides, Bayer Animal Health GmbH, Monheim, Germany
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50011, USA
- Global Innovation, Boehringer Ingelheim Vetmedica GmbH, Binger Str. 173, 55218, Ingelheim am Rhein, Germany
| | | | - Mostafa Zamanian
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Winnie Deuther-Conrad
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318, Leipzig, Germany
| | - Peter Brust
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, 04318, Leipzig, Germany
- The Lübeck Institute of Experimental Dermatology, University Medical Center Schleswig-Holstein, 23562, Lübeck, Germany
| | - Peter J Roy
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.
| |
Collapse
|
4
|
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; 11:79396. [PMID: 36259463 PMCID: PMC9629831 DOI: 10.7554/elife.79396] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [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.
Collapse
Affiliation(s)
- Muntasir Kamal
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Levon Tokmakjian
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Jessica Knox
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Peter Mastrangelo
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Jingxiu Ji
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Hao Cai
- Molecular Medicine Program, Hospital for Sick Children, Toronto, Canada
| | - Jakub W Wojciechowski
- Department of Biomedical Engineering, Wroclaw University of Science and Technolog, Wroclaw, Poland
| | - Michael P Hughes
- Department of Cell and Molecular, St. Jude Children's Research Hospital, Memphis, United States
| | - Kristóf Takács
- Institute of Mathematics, Eötvös Loránd University, Budapest, Hungary
| | - Xiaoquan Chu
- Department of Computer Science and Technology, Tsinghua University, Beijing, China
| | - Jianfeng Pei
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Vince Grolmusz
- Institute of Mathematics, Eötvös Loránd University, Budapest, Hungary
| | - Malgorzata Kotulska
- Department of Biomedical Engineering, Wroclaw University of Science and Technology, Wroclaw, Poland
| | | | - Peter J Roy
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| |
Collapse
|
5
|
Harrington S, Knox JJ, Burns AR, Choo KL, Au A, Kitner M, Haeberli C, Pyche J, D'Amata C, Kim YH, Volpatti JR, Guiliani M, Snider J, Wong V, Palmeira BM, Redman EM, Vaidya AS, Gilleard JS, Stagljar I, Cutler SR, Kulke D, Dowling JJ, Yip CM, Keiser J, Zasada I, Lautens M, Roy PJ. Egg-laying and locomotory screens with C. elegans yield a nematode-selective small molecule stimulator of neurotransmitter release. Commun Biol 2022; 5:865. [PMID: 36002479 PMCID: PMC9402605 DOI: 10.1038/s42003-022-03819-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/08/2022] [Indexed: 12/05/2022] Open
Abstract
Nematode parasites of humans, livestock and crops dramatically impact human health and welfare. Alarmingly, parasitic nematodes of animals have rapidly evolved resistance to anthelmintic drugs, and traditional nematicides that protect crops are facing increasing restrictions because of poor phylogenetic selectivity. Here, we exploit multiple motor outputs of the model nematode C. elegans towards nematicide discovery. This work yielded multiple compounds that selectively kill and/or immobilize diverse nematode parasites. We focus on one compound that induces violent convulsions and paralysis that we call nementin. We find that nementin stimulates neuronal dense core vesicle release, which in turn enhances cholinergic signaling. Consequently, nementin synergistically enhances the potency of widely-used non-selective acetylcholinesterase (AChE) inhibitors, but in a nematode-selective manner. Nementin therefore has the potential to reduce the environmental impact of toxic AChE inhibitors that are used to control nematode infections and infestations. A C. elegans-based screening approach identifies nementin as a nematode-selective nematicide that can be used synergistically with acetylcholinesterase inhibitors
Collapse
Affiliation(s)
- Sean Harrington
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada
| | - Jessica J Knox
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Andrew R Burns
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Ken-Loon Choo
- The Department of Chemistry, University of Toronto, Toronto, Canada
| | - Aaron Au
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
| | - Megan Kitner
- USDA-ARS Horticultural Crops Research Laboratory, Corvallis, OR, USA
| | - Cecile Haeberli
- Department of Medical Parasitology and Infection Biology, Swiss-Tropical and Public Health Institute, (Swiss TPH), Basel, Switzerland.,Faculty of Science, University of Basel, Basel, Switzerland
| | - Jacob Pyche
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada
| | - Cassandra D'Amata
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada
| | - Yong-Hyun Kim
- The Department of Chemistry, University of Toronto, Toronto, Canada
| | - Jonathan R Volpatti
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Canada.,Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada
| | - Maximillano Guiliani
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
| | - Jamie Snider
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada
| | - Victoria Wong
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada
| | - Bruna M Palmeira
- Department of Comparative Biology and Experimental Medicine, Host-Parasite Interactions (HPI) Program, Faculty of Veterinary Medicine, University of Calgary, Calgary, Canada
| | - Elizabeth M Redman
- Department of Comparative Biology and Experimental Medicine, Host-Parasite Interactions (HPI) Program, Faculty of Veterinary Medicine, University of Calgary, Calgary, Canada
| | - Aditya S Vaidya
- Institute for Integrative Genome Biology, University of California, Riverside, CA, USA.,Department of Botany and Plant Sciences, University of California, Riverside, CA, USA
| | - John S Gilleard
- Department of Comparative Biology and Experimental Medicine, Host-Parasite Interactions (HPI) Program, Faculty of Veterinary Medicine, University of Calgary, Calgary, Canada
| | - Igor Stagljar
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada.,Mediterranean Institute for Life Sciences, Split, Croatia.,School of Medicine, University of Split, Split, Croatia
| | - Sean R Cutler
- Institute for Integrative Genome Biology, University of California, Riverside, CA, USA.,Department of Botany and Plant Sciences, University of California, Riverside, CA, USA
| | - Daniel Kulke
- Research Parasiticides, Bayer Animal Health GmbH, Monheim, Germany.,Department of Biomedical Sciences, Iowa State University, Ames, IA, USA.,Global Innovation, Boehringer Ingelheim Vetmedica GmbH, Ingelheim am Rhein, Germany
| | - James J Dowling
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Canada.,Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada
| | - Christopher M Yip
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
| | - Jennifer Keiser
- Department of Medical Parasitology and Infection Biology, Swiss-Tropical and Public Health Institute, (Swiss TPH), Basel, Switzerland.,Faculty of Science, University of Basel, Basel, Switzerland
| | - Inga Zasada
- USDA-ARS Horticultural Crops Research Laboratory, Corvallis, OR, USA
| | - Mark Lautens
- The Department of Chemistry, University of Toronto, Toronto, Canada
| | - Peter J Roy
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada. .,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada. .,Department of Molecular Genetics, University of Toronto, Toronto, Canada.
| |
Collapse
|
6
|
Roy PJ. Temporal Regulation of Gene Expression in Post-Mitotic Cells is Revealed from a Synchronized Population of C. elegans Larvae. MicroPubl Biol 2022; 2022:10.17912/micropub.biology.000587. [PMID: 35783576 PMCID: PMC9242692 DOI: 10.17912/micropub.biology.000587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/07/2022] [Accepted: 06/08/2022] [Indexed: 11/08/2022]
Abstract
Unsupervised Uniform Manifold Approximation and Projection (UMAP) plots of single cell sequencing data from synchronized Caenorhabditis elegans larvae yield tissue-specific data clusters, some of which are plotted as elongated archipelagos. These archipelagos likely represent a single cell type. I show that the pharyngeal archipelagos express a myriad of asynchronous temporally regulated genes, which likely accounts for their elongated topology. With one archipelago, I show that there is a high correlation between a) the base pair distance between the binding sites of an archipelago-specific transcription factor (HLH-6) and the transcriptional start site of the targeted genes and b) the timing of peak gene expression of those genes that are expressed in an archipelago-specific manner. Despite the correlation being made with only four genes, it prompts the hypothesis that the physical distance between a transcription factor and the relevant transcription start site may be an important factor in determining the temporal onset of transcription and transcript abundance.
Collapse
Affiliation(s)
- Peter J. Roy
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada
,
Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada
,
The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
,
Correspondence to: Peter J. Roy (
)
| |
Collapse
|
7
|
Cammalleri SR, Knox J, Roy PJ. Culturing and Screening the Plant Parasitic Nematode Ditylenchus dipsaci. J Vis Exp 2022. [DOI: 10.3791/63438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
|
8
|
Knox J, Joly N, Linossi EM, Carmona-Negrón JA, Jura N, Pintard L, Zuercher W, Roy PJ. A survey of the kinome pharmacopeia reveals multiple scaffolds and targets for the development of novel anthelmintics. Sci Rep 2021; 11:9161. [PMID: 33911106 PMCID: PMC8080662 DOI: 10.1038/s41598-021-88150-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 04/08/2021] [Indexed: 11/10/2022] Open
Abstract
Over one billion people are currently infected with a parasitic nematode. Symptoms can include anemia, malnutrition, developmental delay, and in severe cases, death. Resistance is emerging to the anthelmintics currently used to treat nematode infection, prompting the need to develop new anthelmintics. Towards this end, we identified a set of kinases that may be targeted in a nematode-selective manner. We first screened 2040 inhibitors of vertebrate kinases for those that impair the model nematode Caenorhabditis elegans. By determining whether the terminal phenotype induced by each kinase inhibitor matched that of the predicted target mutant in C. elegans, we identified 17 druggable nematode kinase targets. Of these, we found that nematode EGFR, MEK1, and PLK1 kinases have diverged from vertebrates within their drug-binding pocket. For each of these targets, we identified small molecule scaffolds that may be further modified to develop nematode-selective inhibitors. Nematode EGFR, MEK1, and PLK1 therefore represent key targets for the development of new anthelmintic medicines.
Collapse
Affiliation(s)
- Jessica Knox
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Nicolas Joly
- Programme Équipe Labellisée Ligue Contre Le Cancer, Institut Jacques Monod, UMR7592, Université de Paris, CNRS, Paris, France
| | - Edmond M Linossi
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, 94158, USA
| | - José A Carmona-Negrón
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Natalia Jura
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, 94158, USA.,Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Lionel Pintard
- Programme Équipe Labellisée Ligue Contre Le Cancer, Institut Jacques Monod, UMR7592, Université de Paris, CNRS, Paris, France
| | - William Zuercher
- School of Pharmacy, UNC Eshelman, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Peter J Roy
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada. .,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada.
| |
Collapse
|
9
|
Kamal M, Moshiri H, Magomedova L, Han D, Nguyen KCQ, Yeo M, Knox J, Bagg R, Won AM, Szlapa K, Yip CM, Cummins CL, Hall DH, Roy PJ. The marginal cells of the Caenorhabditis elegans pharynx scavenge cholesterol and other hydrophobic small molecules. Nat Commun 2019; 10:3938. [PMID: 31477732 PMCID: PMC6718421 DOI: 10.1038/s41467-019-11908-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 08/09/2019] [Indexed: 12/24/2022] Open
Abstract
The nematode Caenorhabditis elegans is a bacterivore filter feeder. Through the contraction of the worm’s pharynx, a bacterial suspension is sucked into the pharynx’s lumen. Excess liquid is then shunted out of the buccal cavity through ancillary channels made by surrounding marginal cells. We find that many worm-bioactive small molecules (a.k.a. wactives) accumulate inside of the marginal cells as crystals or globular spheres. Through screens for mutants that resist the lethality associated with one crystallizing wactive we identify a presumptive sphingomyelin-synthesis pathway that is necessary for crystal and sphere accumulation. We find that expression of sphingomyelin synthase 5 (SMS-5) in the marginal cells is not only sufficient for wactive accumulation but is also important for absorbing exogenous cholesterol, without which C. elegans cannot develop. We conclude that sphingomyelin-rich marginal cells act as a sink to scavenge important nutrients from filtered liquid that might otherwise be shunted back into the environment. The C. elegans nematode worm is a filter-feeder and requires dietary sources of cholesterol. Here, the authors show that the C. elegans pharynx works as a filter to scavenge hydrophobic small molecules from its surrounding liquid environment.
Collapse
Affiliation(s)
- Muntasir Kamal
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Houtan Moshiri
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Lilia Magomedova
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, ON, M5S 3M2, Canada
| | - Duhyun Han
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Ken C Q Nguyen
- Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, 10461, USA
| | - May Yeo
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Jessica Knox
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Rachel Bagg
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Amy M Won
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Karolina Szlapa
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada.,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Christopher M Yip
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 3E1, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Carolyn L Cummins
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, ON, M5S 3M2, Canada
| | - David H Hall
- Department of Neuroscience, Albert Einstein College of Medicine, New York, NY, 10461, USA
| | - Peter J Roy
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 1A8, Canada. .,The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 3E1, Canada. .,Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada.
| |
Collapse
|
10
|
D’Souza SA, Rajendran L, Bagg R, Barbier L, van Pel DM, Moshiri H, Roy PJ. The MADD-3 LAMMER Kinase Interacts with a p38 MAP Kinase Pathway to Regulate the Display of the EVA-1 Guidance Receptor in Caenorhabditis elegans. PLoS Genet 2016; 12:e1006010. [PMID: 27123983 PMCID: PMC4849719 DOI: 10.1371/journal.pgen.1006010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 04/05/2016] [Indexed: 11/25/2022] Open
Abstract
The proper display of transmembrane receptors on the leading edge of migrating cells and cell extensions is essential for their response to guidance cues. We previously discovered that MADD-4, which is an ADAMTSL secreted by motor neurons in Caenorhabditis elegans, interacts with an UNC-40/EVA-1 co-receptor complex on muscles to attract plasma membrane extensions called muscle arms. In nematodes, the muscle arm termini harbor the post-synaptic elements of the neuromuscular junction. Through a forward genetic screen for mutants with disrupted muscle arm extension, we discovered that a LAMMER kinase, which we call MADD-3, is required for the proper display of the EVA-1 receptor on the muscle’s plasma membrane. Without MADD-3, EVA-1 levels decrease concomitantly with a reduction of the late-endosomal marker RAB-7. Through a genetic suppressor screen, we found that the levels of EVA-1 and RAB-7 can be restored in madd-3 mutants by eliminating the function of a p38 MAP kinase pathway. We also found that EVA-1 and RAB-7 will accumulate in madd-3 mutants upon disrupting CUP-5, which is a mucolipin ortholog required for proper lysosome function. Together, our data suggests that the MADD-3 LAMMER kinase antagonizes the p38-mediated endosomal trafficking of EVA-1 to the lysosome. In this way, MADD-3 ensures that sufficient levels of EVA-1 are present to guide muscle arm extension towards the source of the MADD-4 guidance cue. In most animals, the physical meeting of the pre- and post-synaptic membranes of the neuromuscular junction occurs via axonal extension towards the muscle. In nematodes, however, motor axons do not extend towards the muscle and instead form a dorsal and ventral cord with relatively few branches. To make the physical connection, the body wall muscles extend membrane projections called muscle arms to the motor axons within the dorsal and ventral cords. Through previous genetic and biochemical analyses with the nematode C. elegans, we identified a neuronally-expressed muscle arm chemoattractant (MADD-4) and its muscle-expressed co-receptor complex (UNC-40/EVA-1). Here, we report our discovery of madd-3, which encodes a LAMMER kinase that is expressed in muscles to regulate muscle arm extension. Genetic analyses revealed that MADD-3 may inhibit a p38 MAP kinase pathway whose normal function is to decrease the abundance of the EVA-1 receptor. In the presence of MADD-3, the activity of the p38 pathway is relatively low, and EVA-1 levels are consequently relatively high. Without MADD-3, the p38 pathway is freed to decrease the abundance of EVA-1. The relationships that we have uncovered between MADD-3, the p38 Map Kinase pathway, and the EVA-1 receptor provide one explanation for the muscle arm defects observed in madd-3 mutants.
Collapse
Affiliation(s)
- Serena A. D’Souza
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- The Collaborative Programme in Developmental Biology, University of Toronto, Toronto, Ontario, Canada
| | - Luckshi Rajendran
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Rachel Bagg
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Louis Barbier
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Derek M. van Pel
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, 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
| | - 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
- The Collaborative Programme in Developmental Biology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
| |
Collapse
|
11
|
Burns AR, Luciani GM, Musso G, Bagg R, Yeo M, Zhang Y, Rajendran L, Glavin J, Hunter R, Redman E, Stasiuk S, Schertzberg M, Angus McQuibban G, Caffrey CR, Cutler SR, Tyers M, Giaever G, Nislow C, Fraser AG, MacRae CA, Gilleard J, Roy PJ. Caenorhabditis elegans is a useful model for anthelmintic discovery. Nat Commun 2015; 6:7485. [PMID: 26108372 PMCID: PMC4491176 DOI: 10.1038/ncomms8485] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 05/13/2015] [Indexed: 12/13/2022] Open
Abstract
Parasitic nematodes infect one quarter of the world's population and impact all humans through widespread infection of crops and livestock. Resistance to current anthelmintics has prompted the search for new drugs. Traditional screens that rely on parasitic worms are costly and labour intensive and target-based approaches have failed to yield novel anthelmintics. Here, we present our screen of 67,012 compounds to identify those that kill the non-parasitic nematode Caenorhabditis elegans. We then rescreen our hits in two parasitic nematode species and two vertebrate models (HEK293 cells and zebrafish), and identify 30 structurally distinct anthelmintic lead molecules. Genetic screens of 19 million C. elegans mutants reveal those nematicides for which the generation of resistance is and is not likely. We identify the target of one lead with nematode specificity and nanomolar potency as complex II of the electron transport chain. This work establishes C. elegans as an effective and cost-efficient model system for anthelmintic discovery.
Collapse
Affiliation(s)
- Andrew R. Burns
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - Genna M. Luciani
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Gabriel Musso
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, and Harvard Stem Cell Institute, Boston, Massachusetts 02115, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Rachel Bagg
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - May Yeo
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - Yuqian Zhang
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - Luckshika Rajendran
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - John Glavin
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - Robert Hunter
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - Elizabeth Redman
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4Z6
| | - Susan Stasiuk
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4Z6
| | - Michael Schertzberg
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
| | - G. Angus McQuibban
- Department of Biochemistry, University of Toronto, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8
| | - Conor R. Caffrey
- Center for Discovery and Innovation in Parasitic Diseases and Department of Pathology, University of California, San Francisco, California 94158, USA
| | - Sean R. Cutler
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA
| | - Mike Tyers
- Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Quebec, Canada H3T 1J4
| | - Guri Giaever
- Department of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
| | - Corey Nislow
- Department of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
| | - Andy G. Fraser
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Calum A. MacRae
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, and Harvard Stem Cell Institute, Boston, Massachusetts 02115, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - John Gilleard
- Department of Comparative Biology and Experimental Medicine, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4Z6
| | - Peter J. Roy
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E1
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| |
Collapse
|
12
|
Chan KKM, Seetharaman A, Bagg R, Selman G, Zhang Y, Kim J, Roy PJ. EVA-1 functions as an UNC-40 Co-receptor to enhance attraction to the MADD-4 guidance cue in Caenorhabditis elegans. PLoS Genet 2014; 10:e1004521. [PMID: 25122090 PMCID: PMC4133157 DOI: 10.1371/journal.pgen.1004521] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 06/03/2014] [Indexed: 01/28/2023] Open
Abstract
We recently discovered a secreted and diffusible midline cue called MADD-4 (an ADAMTSL) that guides migrations along the dorsoventral axis of the nematode Caenorhabditis elegans. We showed that the transmembrane receptor, UNC-40 (DCC), whose canonical ligand is the UNC-6 (netrin) guidance cue, is required for extension towards MADD-4. Here, we demonstrate that MADD-4 interacts with an EVA-1/UNC-40 co-receptor complex to attract cell extensions. EVA-1 is a conserved transmembrane protein with predicted galactose-binding lectin domains. EVA-1 functions in the same pathway as MADD-4, physically interacts with both MADD-4 and UNC-40, and enhances UNC-40's sensitivity to the MADD-4 cue. This enhancement is especially important in the presence of UNC-6. In EVA-1's absence, UNC-6 interferes with UNC-40's responsiveness to MADD-4; in UNC-6's absence, UNC-40's responsiveness to MADD-4 is less dependent on EVA-1. By enabling UNC-40 to respond to MADD-4 in the presence of UNC-6, EVA-1 may increase the precision by which UNC-40-directed processes can reach their MADD-4-expressing targets within a field of the UNC-6 guidance cue.
Collapse
Affiliation(s)
- Kevin Ka Ming Chan
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Ashwin Seetharaman
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
- The Collaborative Programme in Developmental Biology, University of Toronto, Toronto, Ontario, Canada
| | - Rachel Bagg
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Guillermo Selman
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Yuqian Zhang
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- The Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Joowan Kim
- Department of Molecular Genetics, 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
- The Collaborative Programme in Developmental Biology, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
13
|
Wallace IM, Urbanus ML, Luciani GM, Burns AR, Han MKL, Wang H, Arora K, Heisler LE, Proctor M, St Onge RP, Roemer T, Roy PJ, Cummins CL, Bader GD, Nislow C, Giaever G. Compound prioritization methods increase rates of chemical probe discovery in model organisms. ACTA ACUST UNITED AC 2012; 18:1273-83. [PMID: 22035796 DOI: 10.1016/j.chembiol.2011.07.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 06/29/2011] [Accepted: 07/15/2011] [Indexed: 11/30/2022]
Abstract
Preselection of compounds that are more likely to induce a phenotype can increase the efficiency and reduce the costs for model organism screening. To identify such molecules, we screened ~81,000 compounds in Saccharomyces cerevisiae and identified ~7500 that inhibit cell growth. Screening these growth-inhibitory molecules across a diverse panel of model organisms resulted in an increased phenotypic hit-rate. These data were used to build a model to predict compounds that inhibit yeast growth. Empirical and in silico application of the model enriched the discovery of bioactive compounds in diverse model organisms. To demonstrate the potential of these molecules as lead chemical probes, we used chemogenomic profiling in yeast and identified specific inhibitors of lanosterol synthase and of stearoyl-CoA 9-desaturase. As community resources, the ~7500 growth-inhibitory molecules have been made commercially available and the computational model and filter used are provided.
Collapse
Affiliation(s)
- Iain M Wallace
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Alexander M, Selman G, Seetharaman A, Chan KKM, D'Souza SA, Byrne AB, Roy PJ. MADD-2, a homolog of the Opitz syndrome protein MID1, regulates guidance to the midline through UNC-40 in Caenorhabditis elegans. Dev Cell 2010; 18:961-72. [PMID: 20627078 DOI: 10.1016/j.devcel.2010.05.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 03/29/2010] [Accepted: 04/14/2010] [Indexed: 10/19/2022]
Abstract
The body muscles of Caenorhabditis elegans extend plasma membrane extensions called muscle arms to the midline motor axons to form the postsynaptic membrane of the neuromuscular junction. Through a screen for muscle arm development defective (Madd) mutants, we previously discovered that the UNC-40/DCC guidance receptor directs muscle arm extension through the Rho-GEF UNC-73. Here, we describe a gene identified through our mutant screen called madd-2, and show that it functions in an UNC-40 pathway. MADD-2 is a C1-TRIM protein and a homolog of human MID1, mutations in which cause Opitz Syndrome. We demonstrate that MADD-2 functions cell autonomously to direct muscle and axon extensions to the ventral midline of worms. Our results suggest that MADD-2 may enhance UNC-40 pathway activity by facilitating an interaction between UNC-40 and UNC-73. The analogous phenotypes that result from MADD-2 and MID1 mutations suggest that C1-TRIM proteins may have a conserved biological role in midline-oriented developmental events.
Collapse
Affiliation(s)
- Mariam Alexander
- Department of Molecular Genetics, The Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, ON M5S 3E1, Canada
| | | | | | | | | | | | | |
Collapse
|
15
|
Abstract
This paper presents a visually servoed micropositioning system capable of automatically extracting locomotive features of Caenorhabditis elegans online at a full 30 Hz. The employment of Gaussian Pyramid Level-2 images significantly reduces the image size by 16-fold and permits real-time feature extraction, without sacrificing accuracy due to the cubic smoothing spline fitting. The automated micropositioning system is capable of revealing subtle differences in locomotive behavior across strains. A total of 128 worms of four C. elegans strains with different numbers of muscle arms were continuously tracked for 3 min per sample, and locomotive features were extracted online. Validated by experiments, the innovation in image analysis, or data reduction without sacrificing accuracy allows for rapid, online, and accurate analysis of streaming videos of C. elegans and other similar microorganisms.
Collapse
Affiliation(s)
- Wenhui Wang
- Mechanical Engineering, University of Canterbury, New Zealand
| | - Yu Sun
- Mechanical and Industrial Engineering, University of Toronto, Canada
| | - Scott J. Dixon
- Molecular and Medical Genetics, University of Toronto, Canada
| | | | - Peter J. Roy
- Molecular and Medical Genetics, University of Toronto, Canada
| |
Collapse
|
16
|
Arnoldo A, Curak J, Kittanakom S, Chevelev I, Lee VT, Sahebol-Amri M, Koscik B, Ljuma L, Roy PJ, Bedalov A, Giaever G, Nislow C, Merrill RA, Lory S, Stagljar I. Identification of small molecule inhibitors of Pseudomonas aeruginosa exoenzyme S using a yeast phenotypic screen. PLoS Genet 2008; 4:e1000005. [PMID: 18454192 PMCID: PMC2265467 DOI: 10.1371/journal.pgen.1000005] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Accepted: 01/17/2008] [Indexed: 11/19/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen that is a key factor in the mortality of cystic fibrosis patients, and infection represents an increased threat for human health worldwide. Because resistance of Pseudomonas aeruginosa to antibiotics is increasing, new inhibitors of pharmacologically validated targets of this bacterium are needed. Here we demonstrate that a cell-based yeast phenotypic assay, combined with a large-scale inhibitor screen, identified small molecule inhibitors that can suppress the toxicity caused by heterologous expression of selected Pseudomonas aeruginosa ORFs. We identified the first small molecule inhibitor of Exoenzyme S (ExoS), a toxin involved in Type III secretion. We show that this inhibitor, exosin, modulates ExoS ADP-ribosyltransferase activity in vitro, suggesting the inhibition is direct. Moreover, exosin and two of its analogues display a significant protective effect against Pseudomonas infection in vivo. Furthermore, because the assay was performed in yeast, we were able to demonstrate that several yeast homologues of the known human ExoS targets are likely ADP-ribosylated by the toxin. For example, using an in vitro enzymatic assay, we demonstrate that yeast Ras2p is directly modified by ExoS. Lastly, by surveying a collection of yeast deletion mutants, we identified Bmh1p, a yeast homologue of the human FAS, as an ExoS cofactor, revealing that portions of the bacterial toxin mode of action are conserved from yeast to human. Taken together, our integrated cell-based, chemical-genetic approach demonstrates that such screens can augment traditional drug screening approaches and facilitate the discovery of new compounds against a broad range of human pathogens.
Collapse
Affiliation(s)
- Anthony Arnoldo
- Terrence Donnelly Centre for Cellular and Biomolecular Research, Department of Biochemistry, University of Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Jasna Curak
- Terrence Donnelly Centre for Cellular and Biomolecular Research, Department of Biochemistry, University of Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Saranya Kittanakom
- Terrence Donnelly Centre for Cellular and Biomolecular Research, Department of Biochemistry, University of Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Igor Chevelev
- Terrence Donnelly Centre for Cellular and Biomolecular Research, Department of Biochemistry, University of Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Vincent T. Lee
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mehdi Sahebol-Amri
- Terrence Donnelly Centre for Cellular and Biomolecular Research, Department of Biochemistry, University of Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Becky Koscik
- Terrence Donnelly Centre for Cellular and Biomolecular Research, Department of Biochemistry, University of Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Lana Ljuma
- Terrence Donnelly Centre for Cellular and Biomolecular Research, Department of Biochemistry, University of Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Peter J. Roy
- Terrence Donnelly Centre for Cellular and Biomolecular Research, Department of Biochemistry, University of Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Antonio Bedalov
- Clinical Research and Human Biology Divisions, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Guri Giaever
- Terrence Donnelly Centre for Cellular and Biomolecular Research, Department of Biochemistry, University of Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
- Department of Pharmaceutical Sciences, University of Toronto, Ontario, Canada
| | - Corey Nislow
- Terrence Donnelly Centre for Cellular and Biomolecular Research, Department of Biochemistry, University of Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
- Department of Pharmaceutical Sciences, University of Toronto, Ontario, Canada
| | - Rod A. Merrill
- Department of Molecular and Cellular Biology, University of Guelph, Ontario, Canada
| | - Stephen Lory
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Igor Stagljar
- Terrence Donnelly Centre for Cellular and Biomolecular Research, Department of Biochemistry, University of Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
- * E-mail:
| |
Collapse
|
17
|
Burns AR, Kwok TCY, Howard A, Houston E, Johanson K, Chan A, Cutler SR, McCourt P, Roy PJ. High-throughput screening of small molecules for bioactivity and target identification in Caenorhabditis elegans. Nat Protoc 2007; 1:1906-14. [PMID: 17487175 DOI: 10.1038/nprot.2006.283] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This protocol describes a procedure for screening small molecules for bioactivity and a genetic approach to target identification using the nematode Caenorhabditis elegans as a model system. Libraries of small molecules are screened in 24-well plates that contain a solid agar substrate. On top of the agar mixture, one small-molecule species is deposited into each well, along with worm food (E. coli), and two third-stage or fourth-stage larval worms using a COPAS (Complex Object Parametric Analyzer and Sorter) Biosort. Three to five days later the plates are screened for phenotype. Images of the wells are acquired and archived using a HiDI 2100 automated imaging system (Elegenics). Up to 2,400 chemicals can be screened per week. To identify the predicted protein target of a bioactive molecule, wild-type worms are mutagenized using ethylmethanesulfonate (EMS). Progeny are screened for individuals resistant to the molecules effects. The candidate mutant target that confers resistance is then identified. Target identification might take months.
Collapse
Affiliation(s)
- Andrew R Burns
- Department of Medical Genetics and Microbiology, The Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Byrne AB, Weirauch MT, Wong V, Koeva M, Dixon SJ, Stuart JM, Roy PJ. A global analysis of genetic interactions in Caenorhabditis elegans. J Biol 2007; 6:8. [PMID: 17897480 PMCID: PMC2373897 DOI: 10.1186/jbiol58] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Revised: 07/31/2007] [Accepted: 08/17/2007] [Indexed: 01/10/2023] Open
Abstract
Background Understanding gene function and genetic relationships is fundamental to our efforts to better understand biological systems. Previous studies systematically describing genetic interactions on a global scale have either focused on core biological processes in protozoans or surveyed catastrophic interactions in metazoans. Here, we describe a reliable high-throughput approach capable of revealing both weak and strong genetic interactions in the nematode Caenorhabditis elegans. Results We investigated interactions between 11 'query' mutants in conserved signal transduction pathways and hundreds of 'target' genes compromised by RNA interference (RNAi). Mutant-RNAi combinations that grew more slowly than controls were identified, and genetic interactions inferred through an unbiased global analysis of the interaction matrix. A network of 1,246 interactions was uncovered, establishing the largest metazoan genetic-interaction network to date. We refer to this approach as systematic genetic interaction analysis (SGI). To investigate how genetic interactions connect genes on a global scale, we superimposed the SGI network on existing networks of physical, genetic, phenotypic and coexpression interactions. We identified 56 putative functional modules within the superimposed network, one of which regulates fat accumulation and is coordinated by interactions with bar-1(ga80), which encodes a homolog of β-catenin. We also discovered that SGI interactions link distinct subnetworks on a global scale. Finally, we showed that the properties of genetic networks are conserved between C. elegans and Saccharomyces cerevisiae, but that the connectivity of interactions within the current networks is not. Conclusions Synthetic genetic interactions may reveal redundancy among functional modules on a global scale, which is a previously unappreciated level of organization within metazoan systems. Although the buffering between functional modules may differ between species, studying these differences may provide insight into the evolution of divergent form and function.
Collapse
Affiliation(s)
- Alexandra B Byrne
- Department of Medical Genetics and Microbiology, The Terrence Donnelly Centre for Cellular and Biomolecular Research, 160 College St, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Collaborative Program in Developmental Biology, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Matthew T Weirauch
- Department of Biomolecular Engineering, 1156 High Street, Mail Stop SOE2, University of California, Santa Cruz, CA 95064, USA
| | - Victoria Wong
- Department of Medical Genetics and Microbiology, The Terrence Donnelly Centre for Cellular and Biomolecular Research, 160 College St, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Martina Koeva
- Department of Biomolecular Engineering, 1156 High Street, Mail Stop SOE2, University of California, Santa Cruz, CA 95064, USA
| | - Scott J Dixon
- Department of Medical Genetics and Microbiology, The Terrence Donnelly Centre for Cellular and Biomolecular Research, 160 College St, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Collaborative Program in Developmental Biology, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Joshua M Stuart
- Department of Biomolecular Engineering, 1156 High Street, Mail Stop SOE2, University of California, Santa Cruz, CA 95064, USA
| | - Peter J Roy
- Department of Medical Genetics and Microbiology, The Terrence Donnelly Centre for Cellular and Biomolecular Research, 160 College St, University of Toronto, Toronto, ON, M5S 3E1, Canada
- Collaborative Program in Developmental Biology, University of Toronto, Toronto, ON, M5S 3E1, Canada
| |
Collapse
|
19
|
Von Stetina SE, Watson JD, Fox RM, Olszewski KL, Spencer WC, Roy PJ, Miller DM. Cell-specific microarray profiling experiments reveal a comprehensive picture of gene expression in the C. elegans nervous system. Genome Biol 2007; 8:R135. [PMID: 17612406 PMCID: PMC2323220 DOI: 10.1186/gb-2007-8-7-r135] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Revised: 06/13/2007] [Accepted: 07/05/2007] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND With its fully sequenced genome and simple, well-defined nervous system, the nematode Caenorhabditis elegans offers a unique opportunity to correlate gene expression with neuronal differentiation. The lineal origin, cellular morphology and synaptic connectivity of each of the 302 neurons are known. In many instances, specific behaviors can be attributed to particular neurons or circuits. Here we describe microarray-based methods that monitor gene expression in C. elegans neurons and, thereby, link comprehensive profiles of neuronal transcription to key developmental and functional properties of the nervous system. RESULTS We employed complementary microarray-based strategies to profile gene expression in the embryonic and larval nervous systems. In the MAPCeL (Microarray Profiling C. elegans cells) method, we used fluorescence activated cell sorting (FACS) to isolate GFP-tagged embryonic neurons for microarray analysis. To profile the larval nervous system, we used the mRNA-tagging technique in which an epitope-labeled mRNA binding protein (FLAG-PAB-1) was transgenically expressed in neurons for immunoprecipitation of cell-specific transcripts. These combined approaches identified approximately 2,500 mRNAs that are highly enriched in either the embryonic or larval C. elegans nervous system. These data are validated in part by the detection of gene classes (for example, transcription factors, ion channels, synaptic vesicle components) with established roles in neuronal development or function. Of particular interest are 19 conserved transcripts of unknown function that are also expressed in the mammalian brain. In addition to utilizing these profiling approaches to define stage-specific gene expression, we also applied the mRNA-tagging method to fingerprint a specific neuron type, the A-class group of cholinergic motor neurons, during early larval development. A comparison of these data to a MAPCeL profile of embryonic A-class motor neurons identified genes with common functions in both types of A-class motor neurons as well as transcripts with roles specific to each motor neuron type. CONCLUSION We describe microarray-based strategies for generating expression profiles of embryonic and larval C. elegans neurons. These methods can be applied to particular neurons at specific developmental stages and, therefore, provide an unprecedented opportunity to obtain spatially and temporally defined snapshots of gene expression in a simple model nervous system.
Collapse
Affiliation(s)
- Stephen E Von Stetina
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232-8240, USA
| | - Joseph D Watson
- Graduate Program in Neuroscience, Center for Molecular Neuroscience, Vanderbilt University, Nashville, TN 37232-8548, USA
| | - Rebecca M Fox
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232-8240, USA
- Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Kellen L Olszewski
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232-8240, USA
- Department of Molecular Biology, Lewis-Sigler Institute for Integrative Genomics, Princeton University 246 Carl Icahn Laboratory, Princeton NJ 08544, USA
| | - W Clay Spencer
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232-8240, USA
| | - Peter J Roy
- Department of Medical Genetics and Microbiology, Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 1A, Canada
| | - David M Miller
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232-8240, USA
- Graduate Program in Neuroscience, Center for Molecular Neuroscience, Vanderbilt University, Nashville, TN 37232-8548, USA
| |
Collapse
|
20
|
Kwok TCY, Ricker N, Fraser R, Chan AW, Burns A, Stanley EF, McCourt P, Cutler SR, Roy PJ. A small-molecule screen in C. elegans yields a new calcium channel antagonist. Nature 2006; 441:91-5. [PMID: 16672971 DOI: 10.1038/nature04657] [Citation(s) in RCA: 227] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Accepted: 02/14/2006] [Indexed: 11/08/2022]
Abstract
Small-molecule inhibitors of protein function are powerful tools for biological analysis and can lead to the development of new drugs. However, a major bottleneck in generating useful small-molecule tools is target identification. Here we show that Caenorhabditis elegans can provide a platform for both the discovery of new bioactive compounds and target identification. We screened 14,100 small molecules for bioactivity in wild-type worms and identified 308 compounds that induce a variety of phenotypes. One compound that we named nemadipine-A induces marked defects in morphology and egg-laying. Nemadipine-A resembles a class of widely prescribed anti-hypertension drugs called the 1,4-dihydropyridines (DHPs) that antagonize the alpha1-subunit of L-type calcium channels. Through a genetic suppressor screen, we identified egl-19 as the sole candidate target of nemadipine-A, a conclusion that is supported by several additional lines of evidence. egl-19 encodes the only L-type calcium channel alpha1-subunit in the C. elegans genome. We show that nemadipine-A can also antagonize vertebrate L-type calcium channels, demonstrating that worms and vertebrates share the orthologous protein target. Conversely, FDA-approved DHPs fail to elicit robust phenotypes, making nemadipine-A a unique tool to screen for genetic interactions with this important class of drugs. Finally, we demonstrate the utility of nemadipine-A by using it to reveal redundancy among three calcium channels in the egg-laying circuit. Our study demonstrates that C. elegans enables rapid identification of new small-molecule tools and their targets.
Collapse
Affiliation(s)
- Trevor C Y Kwok
- Department of Medical Genetics and Microbiology, and The Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Abstract
Striated muscles from Drosophila and several vertebrates extend plasma membrane to facilitate the formation of the neuromuscular junction(NMJ) during development. However, the regulation of these membrane extensions is poorly understood. In C. elegans, the body wall muscles (BWMs)also have plasma membrane extensions called muscle arms that are guided to the motor axons where they form the postsynaptic element of the NMJ. To investigate the regulation of muscle membrane extension, we screened 871 genes by RNAi for ectopic muscle membrane extensions (EMEs) in C. elegans. We discovered that an FGF pathway, including let-756(FGF), egl-15(FGF receptor), sem-5(GRB2) and other genes negatively regulates plasma membrane extension from muscles. Although compromised FGF pathway activity results in EMEs, hyperactivity of the pathway disrupts larval muscle arm extension, a phenotype we call muscle arm extension defective or MAD. We show that expression of egl-15 and sem-5 in the BWMs are each necessary and sufficient to prevent EMEs. Furthermore, we demonstrate that let-756 expression from any one of several tissues can rescue the EMEs of let-756 mutants, suggesting that LET-756 does not guide muscle membrane extensions. Our screen also revealed that loss-of-function in laminin and integrin components results in both MADs and EMEs, the latter of which are suppressed by hyperactive FGF signaling. Our data are consistent with a model in which integrins and laminins are needed for directed muscle arm extension to the nerve cords, while FGF signaling provides a general mechanism to regulate muscle membrane extension.
Collapse
Affiliation(s)
- Scott J Dixon
- Department of Medical Genetics and Microbiology, Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, M5S 1A, Canada
| | | | | | | | | |
Collapse
|
22
|
Abstract
A 14-item questionnaire measure of activism regarding the nuclear arms race is described. Scale development analyses were conducted on 227 subjects, and internal consistency reliabilities ranged from .56 to .91 for scales assessing four aspects of activism on this issue. High correlations were obtained between these brief scales and corresponding measures derived from a 50-item long form. Responses of five subject groups were also compared: workers in defense industries, participants in a Republican party meeting, graduate students in psychology, religious teachers, and peace activists. Applications of this measure for study of the behavioral component of responses to the nuclear arms race are discussed.
Collapse
Affiliation(s)
- P D Werner
- California School of Professional Psychology, Berkeley, USA
| | | |
Collapse
|
23
|
Abstract
The functional module is fast becoming the operational unit of the postgenomics era. A new report in Nature by Gunsalus and colleagues describes, using a multiply supported network, functional modules within early C. elegans embryos and identifies several new components of known molecular machines (Gunsalus et al., 2005).
Collapse
Affiliation(s)
- Peter J Roy
- Department of Medical Genetics and Microbiology, The Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Ontario, Canada
| | | |
Collapse
|
24
|
Abstract
In several types of animals, muscle cells use membrane extensions to contact motor axons during development. To better understand the process of membrane extension in muscle cells, we investigated the development of Caenorhabditis elegans muscle arms, which extend to motor axons and form the postsynaptic element of the neuromuscular junction. We found that muscle arm development is a highly regulated process: the number of muscle arms extended by each muscle, the shape of the muscle arms and the path taken by the muscle arms to reach the motor axons are largely stereotypical. We also investigated the role of several cytoskeletal components and regulators during arm development, and found that tropomyosin (LEV-11), the actin depolymerizing activity of ADF/cofilin (UNC-60B) and, surprisingly, myosin heavy chain B (UNC-54) are each required for muscle arm extension. This is the first evidence that UNC-54, which is found in thick filaments of sarcomeres, can also play a role in membrane extension. The muscle arm phenotypes produced when these genes are mutated support a 'two-phase' model that distinguishes passive muscle arm development in embryogenesis from active muscle arm extension during larval development.
Collapse
Affiliation(s)
- Scott J Dixon
- Department of Medical Genetics and Microbiology, Collaborative Program in Developmental Biology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | | |
Collapse
|
25
|
Abstract
Chromosomes are divided into domains of open chromatin, where genes have the potential to be expressed, and domains of closed chromatin, where genes are not expressed. Classic examples of open chromatin domains include 'puffs' on polytene chromosomes in Drosophila and extended loops from lampbrush chromosomes. If multiple genes were typically expressed together from a single open chromatin domain, the position of co-expressed genes along the chromosomes would appear clustered. To investigate whether co-expressed genes are clustered, we examined the chromosomal positions of the genes expressed in the muscle of Caenorhabditis elegans at the first larval stage. Here we show that co-expressed genes in C. elegans are clustered in groups of 2-5 along the chromosomes, suggesting that expression from a chromatin domain can extend over several genes. These observations reveal a higher-order organization of the structure of the genome, in which the order of the genes along the chromosome id correlated with their expression in specific tissues.
Collapse
Affiliation(s)
- Peter J Roy
- Department of Developmental Biology, Stanford University Medical Center, California 94305, USA
| | | | | | | |
Collapse
|
26
|
Warren CE, Krizus A, Roy PJ, Culotti JG, Dennis JW. The Caenorhabditis elegans gene, gly-2, can rescue the N-acetylglucosaminyltransferase V mutation of Lec4 cells. J Biol Chem 2002; 277:22829-38. [PMID: 11937505 DOI: 10.1074/jbc.m201390200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
UDP-N-acetylglucosamine:alpha-6-d-mannoside beta-1,6-N-acetylglucosaminyltransferase V (GlcNAc-TV) is a regulator of polylactosamine-containing N-glycans and is causally involved in T cell regulation and tumor metastasis. The Caenorhabditis elegans genome contains a single orthologous gene, gly-2, that is transcribed and encodes a 669-residue type II membrane protein that is 36.7% identical to mammalian GlcNAc-TV (Mgat-5). Recombinant GLY-2 possessed GlcNAc-TV activity when assayed in vitro, and protein truncations demonstrated that the N-terminal boundary of the catalytic domain is Ile-138. gly-2 complemented the Phaseolus vulgaris leucoagglutinin binding defect of Chinese hamster ovary Lec4 cells, whereas GLY-2(L116R), an equivalent mutation to that which causes the Lec4A phenotype, could not. We conclude that the worm gene is functionally interchangeable with the mammalian form. GlcNAc-TV activity was detected in wild-type animals but not those homozygous for a deletion allele of gly-2. Activity was restored in mutant animals by an extrachromosomal array that encompassed the gly-2 gene. Green fluorescent protein reporter transgenes driven by the gly-2 promoter were expressed by developing embryos from the late comma stage onward, present in a complex subset of neurons in larvae and, in addition, the spermathecal and pharyngeal-intestinal valves and certain vulval cells of adults. However, no overt phenotypes were observed in animals homozygous for deletion alleles of gly-2.
Collapse
Affiliation(s)
- Charles E Warren
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | | | | | | | | |
Collapse
|
27
|
Ginzburg VE, Roy PJ, Culotti JG. Semaphorin 1a and semaphorin 1b are required for correct epidermal cell positioning and adhesion during morphogenesis in C. elegans. Development 2002; 129:2065-78. [PMID: 11959817 DOI: 10.1242/dev.129.9.2065] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The semaphorin family comprises secreted and transmembrane proteins involved in axon guidance and cell migration. We have isolated and characterized deletion mutants of C. elegans semaphorin 1a (Ce-sema-1a or smp-1) and semaphorin 1b (Ce-sema-1b or smp-2) genes. Both mutants exhibit defects in epidermal functions. For example, the R1.a-derived ray precursor cells frequently fail to change anterior/posterior positions completely relative to their sister tail lateral epidermal precursor cell R1.p, causing ray 1 to be formed anterior to its normal position next to ray 2. The ray cells, which normally separate from the lateral tail seam cell (SET) at the end of L4 stage, remains connected to the SET cell even in adult mutant males. The ray 1 defects are partially penetrant in each single Ce-sema-1 mutant at 20°C, but are greatly enhanced in Ce-sema-1 double mutants, suggesting that Ce-Sema-1a and Ce-Sema-1b function in parallel to regulate ray 1 position. Both mutants also have defects in other aspects of epidermal functions, including head and tail epidermal morphogenesis and touch cell axon migration, whereas, smp-1 mutants alone have defects in defecation and brood size. A feature of smp-1 mutants that is shared with mutants of mab-20 (which encodes Sema-2a) is the abnormal perdurance of contacts between epidermal cells.
Collapse
Affiliation(s)
- Val E Ginzburg
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
| | | | | |
Collapse
|
28
|
Nash B, Colavita A, Zheng H, Roy PJ, Culotti JG. The forkhead transcription factor UNC-130 is required for the graded spatial expression of the UNC-129 TGF-beta guidance factor in C. elegans. Genes Dev 2000; 14:2486-500. [PMID: 11018016 PMCID: PMC316974 DOI: 10.1101/gad.831500] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Secreted proteins required for cellular movements along the circumference of the body wall in Caenorhabditis elegans include UNC-6/netrin and the novel TGF-beta UNC-129. Expression of these proteins is graded along the dorsoventral (D/V) axis, providing polarity information to guide migrations. Here we show that the graded expression of UNC-129 in dorsal but not ventral body muscles depends on unc-130, which encodes a Forkhead transcription factor. The phenotype of unc-130 mutants closely mimics the reported effects of ectopically expressing unc-129 in both dorsal and ventral body muscles (). This fits our present finding that unc-130 cell autonomously represses unc-129 expression in the ventral body muscles. Thus the cell-specific effects of unc-130 on ventral, but not dorsal, body muscle expression of unc-129 accounts for the D/V polarity information required for UNC-129-mediated guidance. Genetic interactions between unc-130 and other guidance genes show that several molecular pathways function in parallel to guide the ventral to dorsal migration of distal tip cells (DTCs) and axonal growth cones in C. elegans. Genetic interactions confirm that UNC-129 does not require the only known type II TGF-beta receptor in C. elegans (DAF-4) for its guidance functions. Also, unc-130 is partially required for male tail morphogenesis and for embryogenesis.
Collapse
Affiliation(s)
- B Nash
- Department of Molecular and Medical Genetics, University of Toronto, Toronto M5S 1A8, Canada
| | | | | | | | | |
Collapse
|
29
|
Roy PJ, Zheng H, Warren CE, Culotti JG. mab-20 encodes Semaphorin-2a and is required to prevent ectopic cell contacts during epidermal morphogenesis in Caenorhabditis elegans. Development 2000; 127:755-67. [PMID: 10648234 DOI: 10.1242/dev.127.4.755] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Semaphorins are a family of secreted and transmembrane proteins known to elicit growth cone repulsion and collapse. We made and characterized a putative null mutant of the C. elegans gene semaphorin-2a (Ce-sema-2a). This mutant failed to complement mutants of mab-20 (Baird, S. E., Fitch, D. H., Kassem, I. A. A. and Emmons, S. W. (1991) Development 113, 515–526). In addition to low-frequency axon guidance errors, mab-20 mutants have unexpected defects in epidermal morphogenesis. Errant epidermal cell migrations affect epidermal enclosure of the embryo, body shape and sensory rays of the male tail. These phenotypic traits are explained by the formation of inappropriate contacts between cells of similar type and suggest that Ce-Sema-2a may normally prevent formation or stabilization of ectopic adhesive contacts between these cells.
Collapse
Affiliation(s)
- P J Roy
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | | | | | | |
Collapse
|
30
|
Wang X, Roy PJ, Holland SJ, Zhang LW, Culotti JG, Pawson T. Multiple ephrins control cell organization in C. elegans using kinase-dependent and -independent functions of the VAB-1 Eph receptor. Mol Cell 1999; 4:903-13. [PMID: 10635316 DOI: 10.1016/s1097-2765(00)80220-8] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Eph receptor (EphR) tyrosine kinases and their ephrin ligands mediate direct cell-to-cell signaling. The C. elegans genome encodes four potential GPI-modified ephrins (EFN-1 to -4) and one EphR (VAB-1). Single and multiple ephrin mutants reveal functions for EFN-1, EFN-2, and EFN-3 in epidermal cell organization that, in aggregate, mirror those of VAB-1. Ephrin mutants have defects in head morphology and enclosure of the embryo by the epidermis and identify ephrin-EphR signaling functions involved in aligning and fusing tail and head epidermal cells, respectively. Biochemical analyses indicate that EFN-1, EFN-2, and EFN-3 jointly activate the VAB-1 tyrosine kinase in vivo. Mutant phenotypes and expression pattern analysis suggest that multiple ephrins are involved in distinct aspects of kinase-dependent and kinase-independent VAB-1 signaling required for proper cell organization during development in C. elegans.
Collapse
Affiliation(s)
- X Wang
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | | | | | | | | | | |
Collapse
|
31
|
Roy PJ, Nash DB, Davant C, Brook RH, Solomon GL. How evidence-based medicine will change the way you practice. Panel discussion. Med Econ 1999; 76:120-2, 127-8, 133. [PMID: 10346053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
|
32
|
Roy PJ. Why I pay all the bills for our practice. Med Econ 1999; 76:55-6, 59. [PMID: 10345664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
|
33
|
Suzuki Y, Yandell MD, Roy PJ, Krishna S, Savage-Dunn C, Ross RM, Padgett RW, Wood WB. A BMP homolog acts as a dose-dependent regulator of body size and male tail patterning in Caenorhabditis elegans. Development 1999; 126:241-50. [PMID: 9847238 DOI: 10.1242/dev.126.2.241] [Citation(s) in RCA: 174] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We cloned the dbl-1 gene, a C. elegans homolog of Drosophila decapentaplegic and vertebrate BMP genes. Loss-of-function mutations in dbl-1 cause markedly reduced body size and defective male copulatory structures. Conversely, dbl-1 overexpression causes markedly increased body size and partly complementary male tail phenotypes, indicating that DBL-1 acts as a dose-dependent regulator of these processes. Evidence from genetic interactions indicates that these effects are mediated by a Smad signaling pathway, for which DBL-1 is a previously unidentified ligand. Our study of the dbl-1 expression pattern suggests a role for neuronal cells in global size regulation as well as male tail patterning.
Collapse
Affiliation(s)
- Y Suzuki
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA. wood@stripe. colorado.edu
| | | | | | | | | | | | | | | |
Collapse
|
34
|
Zheng Y, Roy PJ, Liang P, MacRae TH. Cloning and sequencing of an alpha-tubulin cDNA from Artemia franciscana: evidence for translational regulation of alpha-tubulin synthesis. Biochim Biophys Acta 1998; 1442:419-26. [PMID: 9805005 DOI: 10.1016/s0167-4781(98)00192-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The brine shrimp, Artemia franciscana, exhibits a limited number of tubulin isotypes which change little during early postgastrula growth. In order to better understand the synthesis of alpha-tubulins during Artemia development, a cDNA termed alphaAT1 was cloned and sequenced. Alignment analyses revealed that the polypeptide encoded by alphaAT1 is similar to alpha-tubulins from other species. Hybridization of alphaAT1 to restriction-digested DNA on Southern blots produced a simple banding pattern, indicating that Artemia have a small number of alpha-tubulin genes. Probing of Northern blots demonstrated an abundant supply of alpha-tubulin mRNA in dormant cysts, emerging nauplii and instar I larvae. However, it was not until instar I larvae were produced that the amount of polysomal alpha-tubulin mRNA increased, suggesting that synthesis of the tubulin corresponding to alphaAT1 is translationally controlled. This work provides one of the few examples where tubulin synthesis is thought to be translationally regulated. Moreover, when considered in the light of previous analyses, the findings imply that cell differentiation in postgastrula Artemia and the diversification of microtubule function certain to accompany this process occur with little or no change in alpha-tubulin composition.
Collapse
Affiliation(s)
- Y Zheng
- Dalhousie University, Biology Department, Halifax, N.S. B3H 4J1, Canada
| | | | | | | |
Collapse
|
35
|
Roy PJ. Never count on a managed-care bonus--even though you've earned one. Med Econ 1998; 75:93-4, 97, 101. [PMID: 10181856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
|
36
|
Roy PJ. Lack of insurance killed these patients. Med Econ 1998; 75:168-70m 173. [PMID: 10175887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
|
37
|
Roy PJ. Do insurers really stand behind preventive care? Med Econ 1997; 74:169, 173. [PMID: 10173561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
|
38
|
Roy PJ. Urgent-care centers don't worry me anymore. Med Econ 1997; 74:107-8, 113. [PMID: 10168774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
|
39
|
Roy PJ. Four myths about teaching medical students. Fam Med 1996; 28:613. [PMID: 8909960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
|
40
|
Roy PJ. Now I know why some patients sue. Med Econ 1996; 73:129-31, 135-6. [PMID: 10154679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
|
41
|
Roy PJ. Doonesbury's right: we can stay on schedule. Med Econ 1995; 72:76, 81-2. [PMID: 10152672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
|
42
|
Roy PJ. Four myths about using med students. Med Econ 1995; 72:165-7. [PMID: 10151348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
|
43
|
Roy PJ. Don't shut family physicians out of the hospital. Med Econ 1995; 72:21-2, 24. [PMID: 10140665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
|
44
|
Roy PJ. Why I hound patients for follow-up. Med Econ 1993; 70:65-6, 68. [PMID: 10129279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
|
45
|
Roy PJ. I tell patients: an HMO is like a bus. Med Econ 1992; 69:240-1. [PMID: 10121560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
|
46
|
Roy PJ. Psychiatrists keep me from helping my patients. Med Econ 1992; 69:41, 45. [PMID: 10118108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
|
47
|
Falgueyret JP, Desmarais S, Roy PJ, Riendeau D. N-(4-chlorophenyl)-N-hydroxy-N'-(3-chlorophenyl)urea, a general reducing agent for 5-, 12-, and 15-lipoxygenases and a substrate for their pseudoperoxidase activities. Biochem Cell Biol 1992; 70:228-36. [PMID: 1515123 DOI: 10.1139/o92-034] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Lipoxygenases contain a nonheme iron that undergoes oxidation and reduction during the catalytic cycle. The conversion from the Fe3+ enzyme form to the Fe2+ form can be achieved using reducing inhibitors, a reaction that can be reversed with lipid hydroperoxides. The present study describes the properties of N-(4-chlorophenyl)-N-hydroxy-N'-(3-chlorophenyl)urea (CPHU), which functions as a reducing agent for various lipoxygenases and stimulates the degradation of lipid hydroperoxide catalyzed by these enzymes (pseudoperoxidase activity). CPHU was a substrate for the pseudoperoxidase reaction of purified soybean lipoxygenase-1 with apparent Km values for CPHU and 13-hydroperoxy-9,11-octadecadienoic acid (13-HpODE) of 14 and 15 microM, respectively. CPHU was converted during the pseudoperoxidase reaction to a mixture of products that can be resolved by reverse-phase high pressure liquid chromatography. By comparison with the chemical reaction of CPHU and potassium nitrosodisulfonate, the major enzymatic reaction product was tentatively identified as a one-electron oxidation product of CPHU. At low concentrations (50 microM), dithiothreitol completely protected against the degradation of hydroxyurea without inhibiting the pseudoperoxidase reaction. Under these conditions, the rate of the pseudoperoxidase reaction with CPHU as a substrate can be quantitated by the change in absorbance at 234 nm owing to the consumption of 13-HpODE. In addition to soybean lipoxygenase-1, CPHU was found to be a substrate for the pseudoperoxidase activities of purified recombinant human 5-lipoxygenase and porcine leukocyte 12-lipoxygenase. The results are consistent with CPHU reacting with lipoxygenase by a one-electron oxidation to generate the ferrous enzyme form and the nitroxide radical, which could be reduced back to CPHU by DTT.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- J P Falgueyret
- Department of Biochemistry, Merck Frosst Centre for Therapeutic Research, Kirkland, Que., Canada
| | | | | | | |
Collapse
|