1
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Williams PDE, Brewer MT, Aroian RV, Robertson AP, Martin RJ. The nematode (Ascaris suum) intestine is a location of synergistic anthelmintic effects of Cry5B and levamisole. PLoS Pathog 2024; 20:e1011835. [PMID: 38758969 PMCID: PMC11139322 DOI: 10.1371/journal.ppat.1011835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 05/30/2024] [Accepted: 04/26/2024] [Indexed: 05/19/2024] Open
Abstract
A novel group of biocidal compounds are the Crystal 3D (Cry) and Cytolytic (Cyt) proteins produced by Bacillus thuringiensis (Bt). Some Bt Cry proteins have a selective nematocidal activity, with Cry5B being the most studied. Cry5B kills nematode parasites by binding selectively to membrane glycosphingolipids, then forming pores in the cell membranes of the intestine leading to damage. Cry5B selectively targets multiple species of nematodes from different clades and has no effect against mammalian hosts. Levamisole is a cholinergic anthelmintic that acts by selectively opening L-subtype nicotinic acetylcholine receptor ion-channels (L-AChRs) that have been found on muscles of nematodes. A synergistic nematocidal interaction between levamisole and Cry5B at the whole-worm level has been described previously, but the location, mechanism and time-course of this synergism is not known. In this study we follow the timeline of the effects of levamisole and Cry5B on the Ca2+ levels in enterocyte cells in the intestine of Ascaris suum using fluorescence imaging. The peak Ca2+ responses to levamisole were observed after approximately 10 minutes while the peak responses to activated Cry5B were observed after approximately 80 minutes. When levamisole and Cry5B were applied simultaneously, we observed that the responses to Cry5B were bigger and occurred sooner than when it was applied by itself. It is proposed that the synergism is due to the cytoplasmic Ca2+ overload that is induced by the combination of levamisole opening Ca2+ permeable L-subtype nAChRs and the Ca2+ permeable Cry5B toxin pores produced in the enterocyte plasma membranes. The effect of levamisole potentiates and speeds the actions of Cry5B that gives rise to bigger Ca2+ overloads that accelerates cell-death of the enterocytes.
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Affiliation(s)
- Paul D. E. Williams
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Matthew T. Brewer
- Department of Veterinary Pathology, Iowa State University, Ames, Iowa, United States of America
| | - Raffi V. Aroian
- Program in Molecular Medicine, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - Alan P. Robertson
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Richard J. Martin
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
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2
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Williams PDE, Brewer MT, Aroian R, Robertson AP, Martin RJ. The nematode ( Ascaris suum) intestine is a location of synergistic anthelmintic effects of Cry5B and levamisole. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.20.567786. [PMID: 38045368 PMCID: PMC10690214 DOI: 10.1101/2023.11.20.567786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
A novel group of biocidal compounds are the Crystal 3D (Cry) and Cytolytic (Cyt) proteins produced by Bacillus thuringiensis (Bt). Some Bt Cry proteins have a selective nematocidal activity, with Cry5B being the most studied. Cry5B kills nematode parasites by binding selectively to membrane glycosphingolipids, then forming pores in the cell membranes of the intestine leading to damage. Cry5B selectively targets multiple species of nematodes from different clades and has no effect against mammalian hosts. Levamisole is a cholinomimetic anthelmintic that acts by selectively opening L-subtype nicotinic acetylcholine receptor ion-channels (L-AChRs) that have been found on muscles of nematodes. A synergistic nematocidal interaction between levamisole and Cry5B has been described previously, but the location, mechanism and time-course of this synergism is not known. In this study we follow the timeline of the effects of levamisole and Cry5B on the Ca2+ levels in enterocyte cells from the intestine of Ascaris suum using fluorescence imaging. The peak Ca2+ responses to levamisole were observed after approximately 10 minutes while the peak responses to activated Cry5B were observed after approximately 80 minutes. When levamisole and Cry5B were applied simultaneously, we observed that the responses to Cry5B were bigger and occurred sooner than when it was applied by itself. It is proposed that there is an irreversible cytoplasmic Ca2+ overload that leads to necrotic cell-death in the enterocyte that is induced by levamisole opening Ca2+ permeable L-subtype nAChRs and the development of Ca2+ permeable Cry5B toxin pores in enterocyte plasma membranes. The effects of levamisole potentiate and speed the actions of Cry5B.
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Affiliation(s)
- Paul D. E. Williams
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Matthew T. Brewer
- Department of Veterinary Pathology, Iowa State University, Ames, Iowa, United States of America
| | - Raffi Aroian
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Alan P. Robertson
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Richard J. Martin
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
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3
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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] [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.
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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.
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4
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Marsh AE, Lakritz J. Reflecting on the past and fast forwarding to present day anthelmintic resistant Ancylostoma caninum-A critical issue we neglected to forecast. Int J Parasitol Drugs Drug Resist 2023; 22:36-43. [PMID: 37229949 PMCID: PMC10229760 DOI: 10.1016/j.ijpddr.2023.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 04/28/2023] [Accepted: 04/29/2023] [Indexed: 05/27/2023]
Abstract
Reports of anthelmintic resistance in Ancylostoma caninum are increasing in frequency in the United States of America (USA). In the last few years in vitro and in vivo studies characterized individual isolates, demonstrating multiple anthelmintic drug resistance (MADR). In 2021, the American Association of Veterinary Parasitologists initiated a hookworm task force to address this issue. The first report of drug resistant A. caninum occurred in 1987 in Australian racing Greyhounds. In the last five years multiple case reports and investigations show drug resistant A. caninum is becoming a much greater problem in the USA and now extends beyond racing Greyhounds into the general companion animal dog population. The literature, regarding drug resistance in livestock and equine nematodes, provides helpful guidance along with diagnostic methods to better understand the evolution and selection of canine MADR hookworms; however, there are limitations and caveats due to A. caninum's unique biology and zoonotic potential. Mass drug administration (MDA) of anthelminthic drugs to humans to reduce morbidity associated with human hookworms (Necator americanus) should consider the factors that contributed to the development of MADR A. caninum. Finally, as Greyhound racing undergoes termination in some regions and the retired dogs undergo subsequent rehoming, drug resistant parasites, if present, are carried with them. Drug resistant A. caninum requires greater recognition by the veterinary community, and small animal practitioners need to be aware of the spread into current pet dog populations. The current understanding of anthelmintic resistance, available treatments, and environmental mitigation for these drug resistant A. caninum isolates must be monitored for horizontal spread. A major goal in this emerging problem is to prevent continued dissemination.
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Affiliation(s)
| | - Jeffrey Lakritz
- Veterinary Clinical Sciences, The Ohio State University, USA
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5
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Shaver AO, Wit J, Dilks CM, Crombie TA, Li H, Aroian RV, Andersen EC. Variation in anthelmintic responses are driven by genetic differences among diverse C. elegans wild strains. PLoS Pathog 2023; 19:e1011285. [PMID: 37011090 PMCID: PMC10101645 DOI: 10.1371/journal.ppat.1011285] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 04/13/2023] [Accepted: 03/08/2023] [Indexed: 04/05/2023] Open
Abstract
Treatment of parasitic nematode infections in humans and livestock relies on a limited arsenal of anthelmintic drugs that have historically reduced parasite burdens. However, anthelmintic resistance (AR) is increasing, and little is known about the molecular and genetic causes of resistance for most drugs. The free-living roundworm Caenorhabditis elegans has proven to be a tractable model to understand AR, where studies have led to the identification of molecular targets of all major anthelmintic drug classes. Here, we used genetically diverse C. elegans strains to perform dose-response analyses across 26 anthelmintic drugs that represent the three major anthelmintic drug classes (benzimidazoles, macrocyclic lactones, and nicotinic acetylcholine receptor agonists) in addition to seven other anthelmintic classes. First, we found that C. elegans strains displayed similar anthelmintic responses within drug classes and significant variation across drug classes. Next, we compared the effective concentration estimates to induce a 10% maximal response (EC10) and slope estimates of each dose-response curve of each strain to the laboratory reference strain, which enabled the identification of anthelmintics with population-wide differences to understand how genetics contribute to AR. Because genetically diverse strains displayed differential susceptibilities within and across anthelmintics, we show that C. elegans is a useful model for screening potential nematicides before applications to helminths. Third, we quantified the levels of anthelmintic response variation caused by genetic differences among individuals (heritability) to each drug and observed a significant correlation between exposure closest to the EC10 and the exposure that exhibited the most heritable responses. These results suggest drugs to prioritize in genome-wide association studies, which will enable the identification of AR genes.
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Affiliation(s)
- Amanda O. Shaver
- Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Janneke Wit
- Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Clayton M. Dilks
- Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Timothy A. Crombie
- Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Hanchen Li
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Raffi V. Aroian
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Erik C. Andersen
- Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
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6
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Williams PDE, Kashyap SS, McHugh MA, Brewer MT, Robertson AP, Martin RJ. Diethylcarbamazine, TRP channels and Ca 2+ signaling in cells of the Ascaris intestine. Sci Rep 2022; 12:21317. [PMID: 36494409 PMCID: PMC9734116 DOI: 10.1038/s41598-022-25648-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022] Open
Abstract
The nematode parasite intestine absorbs nutrients, is involved in innate immunity, can metabolize xenobiotics and as we show here, is also a site of action of the anthelmintic, diethylcarbamazine. Diethylcarbamazine (DEC) is used to treat lymphatic filariasis and activates TRP-2, GON-2 & CED-11 TRP channels in Brugia malayi muscle cells producing spastic paralysis. DEC also has stimulatory effects on ascarid nematode parasites. Using PCR techniques, we detected, in Ascaris suum intestine, message for: Asu-trp-2, Asu-gon-2, Asu-ced-11, Asu-ocr-1, Asu-osm-9 and Asu-trpa-1. Comparison of amino-acid sequences of the TRP channels of B. malayi, and A. suum revealed noteworthy similarity, suggesting that the intestine of Ascaris will also be sensitive to DEC. We used Fluo-3AM as a Ca2+ indicator and observed characteristic unsteady time-dependent increases in the Ca2+ signal in the intestine in response to DEC. Application of La3+ and the TRP channel inhibitors, 2-APB or SKF 96365, inhibited DEC mediated increases in intracellular Ca2+. These observations are important because they emphasize that the nematode intestine, in addition to muscle, is a site of action of DEC as well as other anthelmintics. DEC may also enhance the Ca2+ toxicity effects of other anthelmintics acting on the intestine or, increase the effects of other anthelmintics that are metabolized and excreted by the nematode intestine.
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Affiliation(s)
- Paul D E Williams
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | | | - Mark A McHugh
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | - Matthew T Brewer
- Department of Veterinary Pathology, Iowa State University, Ames, IA, USA
| | - Alan P Robertson
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA
| | - Richard J Martin
- Department of Biomedical Sciences, Iowa State University, Ames, IA, USA.
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7
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Bel Y, Andrés-Antón M, Escriche B. Abundance, distribution, and expression of nematicidal crystal protein genes in Bacillus thuringiensis strains from diverse habitats. Int Microbiol 2022; 26:295-308. [PMID: 36484913 PMCID: PMC10148773 DOI: 10.1007/s10123-022-00307-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 11/16/2022] [Accepted: 11/28/2022] [Indexed: 12/13/2022]
Abstract
Abstract Bacillus thuringiensis (Bt) is a Gram-positive bacterium that accumulates pesticidal proteins (Cry and Cyt) in parasporal crystals. Proteins from the Cry5, App6 (formerly Cry6), Cry12, Cry13, Cry14, Cry21, and Xpp55 (formerly Cry55) families have been identified as toxic to nematodes. In this study, a total of 846 Bt strains belonging to four collections were analyzed to determine the diversity and distribution of the Bt Cry nematicidal protein genes. We analyzed their presence by PCR, and positives were confirmed by sequencing. As a result, 164 Bt isolates (20%) contained at least one gene coding for nematicidal Cry proteins. The cry5 and cry21 genes were enriched in collection 1 and were often found together in the same strain. Differently, in collection 4, obtained from similar habitats but after 10 years, cry14 was the gene most frequently found. In collection 2, cry5 and app6 were the most abundant genes, and collection 3 had a low incidence of any of these genes. The results point to high variability in the frequencies of the studied genes depending on the timing, geographical origins, and sources. The occurrence of cry1A, cry2, and cry3 genes was also analyzed and showed that the nematicidal Cry protein genes were frequently accompanied by cry1A + cry2. The expression of the genes was assessed by mass spectrometry showing that only 14% of the positive strains produced nematicidal proteins. To our knowledge, this is the first comprehensive screening that examines the presence and expression of genes from the seven known Bt Cry nematicidal families.
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Affiliation(s)
- Yolanda Bel
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Departament de Genètica, Universitat de València, C/Dr. Moliner, 50, 46100, Burjassot, Spain
| | - Miguel Andrés-Antón
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Departament de Genètica, Universitat de València, C/Dr. Moliner, 50, 46100, Burjassot, Spain
| | - Baltasar Escriche
- Institut de Biotecnologia i Biomedicina (BIOTECMED), Departament de Genètica, Universitat de València, C/Dr. Moliner, 50, 46100, Burjassot, Spain.
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8
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Suárez G, Alcántara I, Salinas G. Caenorhabditis elegans as a valuable model for the study of anthelmintic pharmacodynamics and drug-drug interactions: The case of ivermectin and eprinomectin. Front Pharmacol 2022; 13:984905. [PMID: 36339613 PMCID: PMC9627147 DOI: 10.3389/fphar.2022.984905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 10/03/2022] [Indexed: 11/16/2022] Open
Abstract
Caenorhabditis elegans is a free-living nematode that has been validated for anthelmintic drug screening. However, this model has not been used to address anthelmintic dose-response-time and drug-drug interactions through matrix array methodology. Eprinomectin (EPM) and Ivermectin (IVM) are macrocyclic lactones widely used as anthelmintics. Despite being very similar, EPM and IVM are combined in commercial formulations or mixed by farmers, under the assumption that the combination would increase their efficacy. However, there is no data reported on the pharmacological evaluation of the combination of both drugs. In this study, we assessed the pharmacodynamics and drug-drug interactions of these two anthelmintic drugs. Since the action of these drugs causes worm paralysis, we used an infrared motility assay to measure EPM and IVM effects on worm movement over time. The results showed that EPM was slightly more potent than IVM, that drug potency increased with drug time exposure, and that once paralyzed, worms did not recover. Different EPM/IVM concentration ratios were used and synergy and combination sensitivity scores were determined at different exposure times, applying Highest Single Agent (HSA), Loewe additivity, Bliss and Zero Interaction Potency (ZIP) models. The results clearly indicate that there is neither synergy nor antagonism between both macrocyclic lactones. This study shows that it is more relevant to prioritize the exposure time of each individual drug than to combine them to improve their effects. The results highlight the utility of C. elegans to address pharmacodynamics studies, particularly for drug-drug interactions. Models in vitro can be integrated to facilitate preclinical and clinical translational studies and help researchers to understand drug-drug interactions and achieve rational therapeutic regimes.
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Affiliation(s)
- Gonzalo Suárez
- Unidad de Farmacología y Terapéutica, Departamento Hospital y Clínicas Veterinarias, Facultad de Veterinaria, Universidad de la República, Montevideo, Uruguay
- *Correspondence: Gonzalo Suárez, ; Gustavo Salinas,
| | - Ignacio Alcántara
- Unidad de Bioestadística, Departamento de Salud Pública Veterinaria, Facultad de Veterinaria, Universidad de la República, Montevideo, Uruguay
| | - Gustavo Salinas
- Worm Biology Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Departamento de Biociencias, Facultad de Química, Universidad de la República, Montevideo, Uruguay
- *Correspondence: Gonzalo Suárez, ; Gustavo Salinas,
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9
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Urban JF, Nielsen MK, Gazzola D, Xie Y, Beshah E, Hu Y, Li H, Rus F, Flanagan K, Draper A, Vakalapudi S, Li RW, Ostroff GR, Aroian RV. An inactivated bacterium (paraprobiotic) expressing Bacillus thuringiensis Cry5B as a therapeutic for Ascaris and Parascaris spp. infections in large animals. One Health 2021; 12:100241. [PMID: 33889707 PMCID: PMC8048022 DOI: 10.1016/j.onehlt.2021.100241] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 03/22/2021] [Accepted: 03/22/2021] [Indexed: 02/07/2023] Open
Abstract
Ascaris and Parascaris are important parasites in the family Ascarididae, large, ubiquitous intestinal-dwelling nematodes infecting all classes of vertebrates. Parasitic nematode drug resistance in veterinary medicine and drug recalcitrance in human medicine are increasing worldwide, with few if any new therapeutic classes on the horizon. Some of these parasites are zoonotic, e.g., Ascaris is passed from humans to pigs and vice versa. The development of new therapies against this family of parasites would have major implications for both human and livestock health. Here we tested the therapeutic ability of a paraprobiotic or dead probiotic that expresses the Bacillus thuringiensis Cry5B protein with known anthelmintic properties, against zoonotic Ascaris suum and Parascaris spp. This paraprobiotic, known as IBaCC, intoxicated A. suum larvae in vitro and was highly effective in vivo against intestinal A. suum infections in a new mouse model for this parasite. Fermentation was scaled up to 350 l to treat pigs and horses. Single dose Cry5B IBaCC nearly completely cleared A. suum infections in pigs. Furthermore, single dose Cry5B IBaCC drove fecal egg counts in Parascaris-infected foals to zero, showing at least parity with, and potential superiority to, current efficacy of anthelmintics used against this parasite. Cry5B IBaCC therefore represents a new, paraprobiotic One Health approach towards targeting Ascarididae that is safe, effective, massively scalable, stable, and useful in human and veterinary medicine in both the developed and developing regions of the world. IBaCC is Bacillus thuringiensis Cry5B protein crystals trapped inside dead bacteria. IBaCC intoxicates Ascaris suum intestinal parasitic nematodes in vitro. IBaCC is highly effective against A. suum parasites in vivo in mice and pigs. IBaCC is highly effective against related Parascaris parasites in foals. IBaCC represents a new paradigm for treating ascarid parasites of humans and animals.
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Affiliation(s)
- Joseph F Urban
- U. S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal and Parasitic Diseases Laboratory, Beltsville, MD, United States of America.,U. S. Department of Agriculture, Agricultural Research Service, Beltsville Human Nutrition Research Center, Diet, Genomics and Immunology Laboratory, Beltsville, MD, United States of America
| | - Martin K Nielsen
- M.H. Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY, United States of America
| | - David Gazzola
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Yue Xie
- U. S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal and Parasitic Diseases Laboratory, Beltsville, MD, United States of America.,U. S. Department of Agriculture, Agricultural Research Service, Beltsville Human Nutrition Research Center, Diet, Genomics and Immunology Laboratory, Beltsville, MD, United States of America.,Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Sichuan, China
| | - Ethiopia Beshah
- U. S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal and Parasitic Diseases Laboratory, Beltsville, MD, United States of America.,U. S. Department of Agriculture, Agricultural Research Service, Beltsville Human Nutrition Research Center, Diet, Genomics and Immunology Laboratory, Beltsville, MD, United States of America
| | - Yan Hu
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Hanchen Li
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Florentina Rus
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Kelly Flanagan
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Austin Draper
- Synthetic Biomanufacturing Facility, Utah State University, Logan, UT, United States of America
| | - Sridhar Vakalapudi
- Synthetic Biomanufacturing Facility, Utah State University, Logan, UT, United States of America
| | - Robert W Li
- U. S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Animal and Parasitic Diseases Laboratory, Beltsville, MD, United States of America
| | - Gary R Ostroff
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Raffi V Aroian
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, United States of America
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10
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Recombinant Paraprobiotics as a New Paradigm for Treating Gastrointestinal Nematode Parasites of Humans. Antimicrob Agents Chemother 2021; 65:AAC.01469-20. [PMID: 33318013 PMCID: PMC8092541 DOI: 10.1128/aac.01469-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 12/08/2020] [Indexed: 12/11/2022] Open
Abstract
Gastrointestinal nematodes (GINs) of humans, e.g., hookworms, negatively impact childhood growth, cognition, nutrition, educational attainment, income, productivity, and pregnancy. Hundreds of millions of people are targeted with mass drug administration (MDA) of donated benzimidazole anthelmintics. Gastrointestinal nematodes (GINs) of humans, e.g., hookworms, negatively impact childhood growth, cognition, nutrition, educational attainment, income, productivity, and pregnancy. Hundreds of millions of people are targeted with mass drug administration (MDA) of donated benzimidazole anthelmintics. However, benzimidazole efficacy against GINs is suboptimal, and reduced/low efficacy has been seen. Developing an anthelmintic for human MDA is daunting: it must be safe, effective, inexpensive, stable without a cold chain, and massively scalable. Bacillus thuringiensis crystal protein 5B (Cry5B) has anthelmintic properties that could fill this void. Here, we developed an active pharmaceutical ingredient (API) containing B. thuringiensis Cry5B compatible with MDA. We expressed Cry5B in asporogenous B. thuringiensis during vegetative phase, forming cytosolic crystals. These bacteria with cytosolic crystals (BaCC) were rendered inviable (inactivated BaCC [IBaCC]) with food-grade essential oils. IBaCC potency was validated in vitro against nematodes. IBaCC was also potent in vivo against human hookworm infections in hamsters. IBaCC production was successfully scaled to 350 liters at a contract manufacturing facility. A simple fit-for-purpose formulation to protect against stomach digestion and powdered IBaCC were successfully made and used against GINs in hamsters and mice. A pilot histopathology study and blood chemistry workup showed that five daily consecutive doses of 200 mg/kg body weight Cry5B IBaCC (the curative single dose is 40 mg/kg) was nontoxic to hamsters and completely safe. IBaCC is a safe, inexpensive, highly effective, easy-to-manufacture, and scalable anthelmintic that is practical for MDA and represents a new paradigm for treating human GINs.
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11
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Pharmacometric Analysis of Tribendimidine Monotherapy and Combination Therapies To Achieve High Cure Rates in Patients with Hookworm Infections. Antimicrob Agents Chemother 2021; 65:AAC.00714-20. [PMID: 33139276 DOI: 10.1128/aac.00714-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 09/27/2020] [Indexed: 02/06/2023] Open
Abstract
In the treatment of hookworm infections, pharmacotherapy has been only moderately successful and drug resistance is a threat. Therefore, novel treatment options including combination therapies should be considered, in which tribendimidine could play a role. Our aims were to (i) characterize the pharmacokinetics of tribendimidine's metabolites in adolescents receiving tribendimidine monotherapy or in combination with ivermectin or oxantel pamoate, (ii) evaluate possible drug-drug interactions (DDI), (iii) link exposure to response, and (iv) identify a treatment strategy associated with high efficacy, i.e., >90% cure rates (CRs), utilizing model-based simulations. A population pharmacokinetic model was developed for tribendimidine's primary and secondary metabolites, dADT and adADT, in 54 hookworm-positive adolescents, with combination therapy evaluated as a possible covariate. Subsequently, an exposure-response analysis was performed utilizing CRs as response markers. Simulations were performed to identify a treatment strategy to achieve >90% CRs. A two-compartmental model best described metabolite disposition. No pharmacokinetic DDI was identified with ivermectin or oxantel pamoate. All participants receiving tribendimidine plus ivermectin were cured. For the monotherapy arm and the arm including the combination with oxantel pamoate, E max models adequately described the correlation between dADT exposure and probability of being cured, with required exposures to achieve 50% of maximum effect of 39.6 and 15.6 nmol/ml·h, respectively. Based on our simulations, an unrealistically high monotherapy tribendimidine dose would be necessary to achieve CRs of >90%, while combination therapy with ivermectin would meet this desired target product profile. Further clinical studies should be launched to develop this combination for the treatment of hookworm and other helminth infections.
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12
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Sanders J, Xie Y, Gazzola D, Li H, Abraham A, Flanagan K, Rus F, Miller M, Hu Y, Guynn S, Draper A, Vakalapudi S, Petersson KH, Zarlenga D, Li RW, Urban JF, Ostroff GR, Zajac A, Aroian RV. A new paraprobiotic-based treatment for control of Haemonchus contortus in sheep. Int J Parasitol Drugs Drug Resist 2020; 14:230-236. [PMID: 33242790 PMCID: PMC7695930 DOI: 10.1016/j.ijpddr.2020.11.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 11/16/2020] [Accepted: 11/16/2020] [Indexed: 12/21/2022]
Abstract
Haemonchus contortus is a critical parasite of goats and sheep. Infection by this blood-feeding gastrointestinal nematode (GIN) parasite has significant health consequences, especially in lambs and kids. The parasite has developed resistance to virtually all known classes of small molecule anthelmintics used to treat it, giving rise in some areas to multidrug resistant parasites that are very difficult to control. Thus, new anthelmintics are urgently needed. Bacillus thuringiensis (Bt) crystal protein 5B (Cry5B), a naturally occurring protein made by a bacterium widely and safely used around the world as a bioinsecticide, represents a new non-small molecule modality for treating GINs. Cry5B has demonstrated anthelmintic activities against parasites of monogastric animals, including some related to those that infect humans, but has not yet been studied in a ruminant. Here we show that H. contortus adults are susceptible to Cry5B protein in vitro. Cry5B produced in its natural form as a spore-crystal lysate against H. contortus infections in goats had no significant efficacy. However, a new Active Pharmaceutical Ingredient (API) paraprobiotic form of Cry5B called IBaCC (Inactivated Bacterium with Cytosolic Crystals), in which Cry5B crystals are encapsulated in dead Bt cell wall ghosts, showed excellent efficacy in vitro against larval stages of H. contortus and relative protein stability in bovine rumen fluid. When given to sheep experimentally infected with H. contortus as three 60 mg/kg doses, Cry5B IBaCC resulted in significant reductions in fecal egg counts (90%) and parasite burdens (72%), with a very high impact on female parasites (96% reduction). These data indicate that Cry5B IBaCC is a potent new treatment tool for small ruminants in the battle against H. contortus.
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Affiliation(s)
- John Sanders
- Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Yue Xie
- United State Department of Agriculture, Agricultural Research Service, Beltsville Human Nutrition Research Center, Diet, Genomics, Immunology Laboratory, Beltsville, MD, 20705, USA
| | - David Gazzola
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Hanchen Li
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Ambily Abraham
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Kelly Flanagan
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Florentina Rus
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Melanie Miller
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Yan Hu
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA; Biology Department, Worcester State University, Worcester, MA, 01602, USA
| | - Sierra Guynn
- Department of Large Animal Clinical Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Austin Draper
- Synthetic Biomanufacturing Facility, Utah State University, Logan, UT, 84341, USA
| | - Sridhar Vakalapudi
- Synthetic Biomanufacturing Facility, Utah State University, Logan, UT, 84341, USA
| | - Katherine H Petersson
- Department of Fisheries, Animal, and Veterinary Sciences, University of Rhode Island, Kingston, RI, 02881, USA
| | - Dante Zarlenga
- United State Department of Agriculture, Agricultural Research Service, Animal Parasitic Diseases Laboratory, Beltsville, MD, 20705, USA
| | - Robert W Li
- United State Department of Agriculture, Agricultural Research Service, Animal Parasitic Diseases Laboratory, Beltsville, MD, 20705, USA
| | - Joseph F Urban
- United State Department of Agriculture, Agricultural Research Service, Beltsville Human Nutrition Research Center, Diet, Genomics, Immunology Laboratory, Beltsville, MD, 20705, USA; United State Department of Agriculture, Agricultural Research Service, Animal Parasitic Diseases Laboratory, Beltsville, MD, 20705, USA
| | - Gary R Ostroff
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Anne Zajac
- Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Raffi V Aroian
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
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13
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McHugh M, Williams P, Verma S, Powell-Coffman JA, Robertson AP, Martin RJ. Cholinergic receptors on intestine cells of Ascaris suum and activation of nAChRs by levamisole. Int J Parasitol Drugs Drug Resist 2020; 13:38-50. [PMID: 32470835 PMCID: PMC7256660 DOI: 10.1016/j.ijpddr.2020.04.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 04/13/2020] [Accepted: 04/14/2020] [Indexed: 11/19/2022]
Abstract
Cholinergic agonists, like levamisole, are a major class of anthelmintic drugs that are known to act selectively on nicotinic acetylcholine receptors (nAChRs) on the somatic muscle and nerves of nematode parasites to produce their contraction and spastic paralysis. Previous studies have suggested that in addition to the nAChRs found on muscle and nerves, there are nAChRs on non-excitable tissues of nematode parasites. We looked for evidence of nAChRs expression in the cells of the intestine of the large pig nematode, Ascaris suum, using RT-PCR and RNAscope in situ hybridization and detected mRNA of nAChR subunits in the cells. These subunits include components of the putative levamisole receptor in A. suum muscle: Asu-unc-38, Asu-unc-29, Asu-unc-63 and Asu-acr-8. Relative expression of these mRNAs in A. suum intestine was quantified by qPCR. We also looked for and found expression of G protein-linked acetylcholine receptors (Asu-gar-1). We used Fluo-3 AM to detect intracellular calcium changes in response to receptor activation by acetylcholine (as a non-selective agonist) and levamisole (as an L-type nAChR agonist) to look for evidence of functioning nAChRs in the intestine. We found that both acetylcholine and levamisole elicited increases in intracellular calcium but their signal profiles in isolated intestinal tissues were different, suggesting activation of different receptor sets. The levamisole responses were blocked by mecamylamine, a nicotinic receptor antagonist in A. suum, indicating the activation of intestinal nAChRs rather than G protein-linked acetylcholine receptors (GARs) by levamisole. The detection of nAChRs in cells of the intestine, in addition to those on muscles and nerves, reveals another site of action of the cholinergic anthelmintics and a site that may contribute to the synergistic interactions of cholinergic anthelmintics with other anthelmintics that affect the intestine (Cry5B).
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Affiliation(s)
- Mark McHugh
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Paul Williams
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Saurabh Verma
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Jo Anne Powell-Coffman
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Alan P Robertson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Richard J Martin
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
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14
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Charuchaibovorn S, Sanprasert V, Sutthanont N, Hu Y, Abraham A, Ostroff GR, Aroian RV, Jaleta TG, Lok JB, Nuchprayoon S. Bacillus thuringiensis Cry5B is Active against Strongyloides stercoralis in vitro. Am J Trop Med Hyg 2020; 101:1177-1182. [PMID: 31516117 DOI: 10.4269/ajtmh.19-0083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Strongyloidiasis, caused by Strongyloides stercoralis infection, is an important neglected tropical disease that causes significant public health problems in the tropics and subtropics. The disease can persist in hosts for decades and may be life-threatening because of hyperinfection and dissemination. Ivermectin (mostly) and albendazole are the most common anthelmintics used for treatment. Albendazole is suboptimal for this parasite, and although ivermectin is quite effective in immunocompromised patients, a multiple-course regimen is required. Furthermore, reliance on a single drug class for treating intestinal nematodes is a recipe for future failure. Therefore, it is important to discover new anthelmintics to treat or prevent human strongyloidiasis. One promising candidate is the Bacillus thuringiensis crystal protein Cry5B. Cry5B is highly potent against parasitic nematodes, for example, hookworms and Ascaris suum. Here, we investigated the potential of Cry5B against S. stercoralis. Multiple stages of S. stercoralis, including the first larval stage (L1s), infective stage (iL3s), free-living adult stage, and parasitic female stage, were all susceptible to Cry5B as indicated by impairment of motility and decreased viability in vitro. In summary, Cry5B demonstrated strong potential as an effective anthelmintic for treatment and transmission control of human strongyloidiasis, justifying further experiments to investigate in vivo therapeutic efficacy.
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Affiliation(s)
- Sarit Charuchaibovorn
- Siriraj Center of Excellence for Stem Cell Research (SiSCR), Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.,Lymphatic Filariasis and Tropical Medicine Research Unit, Chulalongkorn Medical Research Center, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Vivornpun Sanprasert
- Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Lymphatic Filariasis and Tropical Medicine Research Unit, Chulalongkorn Medical Research Center, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Nataya Sutthanont
- Lymphatic Filariasis and Tropical Medicine Research Unit, Chulalongkorn Medical Research Center, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Yan Hu
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts.,Biology Department, Worcester State University, Worcester, Massachusetts
| | - Ambily Abraham
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Gary R Ostroff
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Raffi V Aroian
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Tegegn G Jaleta
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - James B Lok
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Surang Nuchprayoon
- Lymphatic Filariasis and Tropical Medicine Research Unit, Chulalongkorn Medical Research Center, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.,Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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15
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Sepúlveda-Crespo D, Reguera RM, Rojo-Vázquez F, Balaña-Fouce R, Martínez-Valladares M. Drug discovery technologies: Caenorhabditis elegans as a model for anthelmintic therapeutics. Med Res Rev 2020; 40:1715-1753. [PMID: 32166776 DOI: 10.1002/med.21668] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 12/10/2019] [Accepted: 02/26/2020] [Indexed: 12/16/2022]
Abstract
Helminthiasis is one of the gravest problems worldwide. There is a growing concern on less available anthelmintics and the emergence of resistance creating a major threat to human and livestock health resources. Novel and broad-spectrum anthelmintics are urgently needed. The free-living nematode Caenorhabditis elegans could address this issue through automated high-throughput technologies for the screening of large chemical libraries. This review discusses the strong advantages and limitations for using C elegans as a screening method for anthelmintic drug discovery. C elegans is the best model available for the validation of novel effective drugs in treating most, if not all, helminth infections, and for the elucidation the mode of action of anthelmintic candidates. This review also focuses on available technologies in the discovery of anthelmintics published over the last 15 years with particular attention to high-throughput technologies over conventional screens. On the other hand, this review highlights how combinatorial and nanomedicine strategies could prolong the use of anthelmintics and control resistance problems.
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Affiliation(s)
- Daniel Sepúlveda-Crespo
- Departamento de Ciencias Biomédicas, Facultad de Veterinaria, Universidad de León, León, Spain
| | - Rosa M Reguera
- Departamento de Ciencias Biomédicas, Facultad de Veterinaria, Universidad de León, León, Spain
| | - Francisco Rojo-Vázquez
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), León, Spain.,Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de León, León, Spain
| | - Rafael Balaña-Fouce
- Departamento de Ciencias Biomédicas, Facultad de Veterinaria, Universidad de León, León, Spain
| | - María Martínez-Valladares
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), León, Spain.,Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de León, León, Spain
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16
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Liu M, Panda SK, Luyten W. Plant-Based Natural Products for the Discovery and Development of Novel Anthelmintics against Nematodes. Biomolecules 2020; 10:biom10030426. [PMID: 32182910 PMCID: PMC7175113 DOI: 10.3390/biom10030426] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/27/2020] [Accepted: 03/02/2020] [Indexed: 12/11/2022] Open
Abstract
Intestinal parasitic nematodes infect approximately two billion people worldwide. In the absence of vaccines for human intestinal nematodes, control of infections currently relies mainly on chemotherapy, but resistance is an increasing problem. Thus, there is an urgent need for the discovery and development of new anthelmintic drugs, especially ones with novel mechanisms of action. Medicinal plants hold great promise as a source of effective treatments, including anthelmintic therapy. They have been used traditionally for centuries and are mostly safe (if not, their toxicity is well-known). However, in most medicinal plants the compounds active against nematodes have not been identified thus far. The free-living nematode C. elegans was demonstrated to be an excellent model system for the discovery of new anthelmintics and for characterizing their mechanism of action or resistance. The compounds discussed in this review are of botanical origin and were published since 2002. Most of them need further studies of their toxicity, mechanisms and structure-activity relationship to assess more fully their potential as drugs.
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17
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Sharpton TJ, Combrink L, Arnold HK, Gaulke CA, Kent M. Harnessing the gut microbiome in the fight against anthelminthic drug resistance. Curr Opin Microbiol 2020; 53:26-34. [PMID: 32114334 DOI: 10.1016/j.mib.2020.01.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/20/2020] [Accepted: 01/24/2020] [Indexed: 01/08/2023]
Abstract
Intestinal helminth parasites present major challenges to the welfare of humans and threaten the global food supply. While the discovery of anthelminthic drugs empowered our ability to offset these harms to society, the alarming rise of anthelminthic drug resistance mitigates contemporary efforts to treat and control intestinal helminthic infections. Fortunately, emerging research points to potential opportunities to combat anthelminthic drug resistance by harnessing the gut microbiome as a resource for discovering novel therapeutics and informing responsible drug administration. In this review, we highlight research that demonstrates this potential and provide rationale to support increased investment in efforts to uncover and translationally utilize knowledge about how the gut microbiome mediates intestinal helminthic infection and its outcomes.
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Affiliation(s)
- Thomas J Sharpton
- Department of Microbiology, Oregon State University, Corvallis, OR, 97331, USA; Department of Statistics, Oregon State University, Corvallis, OR, 97331, USA.
| | - Leigh Combrink
- Department of Microbiology, Oregon State University, Corvallis, OR, 97331, USA; Department of Biomedical Sciences, Oregon State University, Corvallis, OR, 97331, USA
| | - Holly K Arnold
- Department of Microbiology, Oregon State University, Corvallis, OR, 97331, USA; Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, 97331, USA
| | | | - Michael Kent
- Department of Microbiology, Oregon State University, Corvallis, OR, 97331, USA; Department of Biomedical Sciences, Oregon State University, Corvallis, OR, 97331, USA
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18
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Kelly P, Hadi-Nezhad F, Liu DY, Lawrence TJ, Linington RG, Ibba M, Ardell DH. Targeting tRNA-synthetase interactions towards novel therapeutic discovery against eukaryotic pathogens. PLoS Negl Trop Dis 2020; 14:e0007983. [PMID: 32106219 PMCID: PMC7046186 DOI: 10.1371/journal.pntd.0007983] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 12/10/2019] [Indexed: 12/22/2022] Open
Abstract
The development of chemotherapies against eukaryotic pathogens is especially challenging because of both the evolutionary conservation of drug targets between host and parasite, and the evolution of strain-dependent drug resistance. There is a strong need for new nontoxic drugs with broad-spectrum activity against trypanosome parasites such as Leishmania and Trypanosoma. A relatively untested approach is to target macromolecular interactions in parasites rather than small molecular interactions, under the hypothesis that the features specifying macromolecular interactions diverge more rapidly through coevolution. We computed tRNA Class-Informative Features in humans and independently in eight distinct clades of trypanosomes, identifying parasite-specific informative features, including base pairs and base mis-pairs, that are broadly conserved over approximately 250 million years of trypanosome evolution. Validating these observations, we demonstrated biochemically that tRNA:aminoacyl-tRNA synthetase (aaRS) interactions are a promising target for anti-trypanosomal drug discovery. From a marine natural products extract library, we identified several fractions with inhibitory activity toward Leishmania major alanyl-tRNA synthetase (AlaRS) but no activity against the human homolog. These marine natural products extracts showed cross-reactivity towards Trypanosoma cruzi AlaRS indicating the broad-spectrum potential of our network predictions. We also identified Leishmania major threonyl-tRNA synthetase (ThrRS) inhibitors from the same library. We discuss why chemotherapies targeting multiple aaRSs should be less prone to the evolution of resistance than monotherapeutic or synergistic combination chemotherapies targeting only one aaRS. Trypanosome parasites pose a significant health risk worldwide. Conventional drug development strategies have proven challenging given the high conservation between humans and pathogens, with off-target toxicity being a common problem. Protein synthesis inhibitors have historically been an attractive target for antimicrobial discovery against bacteria, and more recently for eukaryotic pathogens. Here we propose that exploiting pathogen-specific tRNA-synthetase interactions offers the potential for highly targeted drug discovery. To this end, we improved tRNA gene annotations in trypanosome genomes, identified functionally informative trypanosome-specific tRNA features, and showed that these features are highly conserved over approximately 250 million years of trypanosome evolution. Highlighting the species-specific and broad-spectrum potential of our approach, we identified natural product inhibitors against the parasite translational machinery that have no effect on the homologous human enzyme.
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Affiliation(s)
- Paul Kelly
- The Ohio State University Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, Ohio, United States of America
- Center for RNA Biology, The Ohio State University, Ohio, United States of America
| | - Fatemeh Hadi-Nezhad
- Quantitative and Systems Biology Program, University of California, Merced, California, United States of America
| | - Dennis Y. Liu
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Travis J. Lawrence
- Quantitative and Systems Biology Program, University of California, Merced, California, United States of America
- Biosciences Division, Oak Ridge National Lab, Oak Ridge, Tennessee, United States of America
| | - Roger G. Linington
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Michael Ibba
- The Ohio State University Molecular, Cellular and Developmental Biology Program, The Ohio State University, Columbus, Ohio, United States of America
- Center for RNA Biology, The Ohio State University, Ohio, United States of America
- Department of Microbiology, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail: (MI); (DHA)
| | - David H. Ardell
- Quantitative and Systems Biology Program, University of California, Merced, California, United States of America
- Department of Molecular & Cell Biology, University of California, Merced, California, United States of America
- * E-mail: (MI); (DHA)
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19
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In Vitro and In Vivo Drug-Drug Interaction Study of the Effects of Ivermectin and Oxantel Pamoate on Tribendimidine. Antimicrob Agents Chemother 2018; 63:AAC.00762-18. [PMID: 30323047 DOI: 10.1128/aac.00762-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 10/10/2018] [Indexed: 02/07/2023] Open
Abstract
Soil-transmitted helminth (STH) infections still remain a major health problem in poor rural settings. The lack of efficacious drugs against all STH species raises interest in drug combinations. Drug-drug interactions (DDIs) are, however, of major concern, so careful in vitro and in vivo characterization is needed. The combination of tribendimidine with either ivermectin or oxantel pamoate targets a broad range of STHs and thus represents a promising treatment alternative. Drug-drug interactions, however, have not yet been investigated. Therefore, the effects of combinations of ivermectin, oxantel pamoate, and tribendimidine's active metabolite deacylated amidantel (dADT) on cytochrome P450 (CYP450) metabolism were evaluated, followed by a pharmacokinetic analysis of tribendimidine and ivermectin alone and in combination in healthy rats. Oxantel pamoate is only poorly absorbed and was therefore excluded from pharmacokinetic analysis. No evident effect was observed for tribendimidine-oxantel pamoate at the CYP450 metabolism level, whereas a combination of tribendimidine and ivermectin led to moderately increased CYP2D6 inhibition compared to ivermectin or tribendimidine alone. Coadministration of tribendimidine with ivermectin altered neither the time to maximum concentration of drug in plasma (T max) nor the elimination half-lives of dADT, the acetylated derivative of amidantel (adADT), and ivermectin. While the area under the concentration-versus-time curve (AUC) and maximum concentration of drug in plasma (C max) values of dADT, adADT, and ivermectin are reduced by coadministration, the change is insufficient to declare that a DDI has been detected. Further studies are necessary to understand the observed interaction of tribendimidine and ivermectin, which is not related to P450 metabolism, and its significance for the situation in humans.
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Liu M, Veryser C, Lu JG, Wenseleers T, De Borggraeve WM, Jiang ZH, Luyten W. Bioassay-guided isolation of active substances from Semen Torreyae identifies two new anthelmintic compounds with novel mechanism of action. JOURNAL OF ETHNOPHARMACOLOGY 2018; 224:421-428. [PMID: 29933012 DOI: 10.1016/j.jep.2018.06.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 06/13/2018] [Accepted: 06/18/2018] [Indexed: 06/08/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Semen Torreyae, the seeds of Torreya grandis Fortune ex Lindley (Cephalotaxaceae) is a well-known traditional Chinese medicinal plant recorded in the Chinese Pharmacopeia (2010 version). It is widely used for treating intestinal parasites in China, owing to its desirable efficacy and safety. However, the anthelmintic compounds in Semen Torreyae have not yet been identified. AIM OF THE STUDY This study aims to identify the compounds active against helminths from Semen Torreyae. In addition, we tested whether C. elegans strains resistant to currently-used anthelmintic drugs showed cross-resistance to these compounds. METHODS A bioassay-guided isolation of anthelmintic compounds from Semen Torreyae was performed using a Caenorhabditis elegans (C. elegans) testing model. The structures of active compounds were elucidated by a combination of GC-MS, high resolution MS, and NMR. The median-effect method was employed to generate a combination index (CI) to evaluate the synergistic effect of the anthelmintic compounds. A panel of C. elegans mutant strains resistant against the major anthelmintic drug classes was used to study the cross-resistance to currently-used anthelmintic drugs. A panel of transient receptor potential (TRP) channel mutant strains was also tested to explore the possible mechanisms of action of the anthelmintic compounds. RESULTS The bioassay-guided isolation led to two active compounds, i.e. galangal acetate (IC50: 58.5 ± 8.9 μM) and miogadial (IC50: 25.1 ± 5.4 μM). The combination of galangal acetate and miogadial resulted in a synergistic effect at IC50, IC70, and IC90 levels (CIs < 1). Galangal acetate and miogadial demonstrated similar activity against drug-resistant C. elegans strains compared to the wild-type strain. In addition, none of the TRP mutants was significantly resistant to galangal acetate or miogadial compared to wild type worms. CONCLUSIONS We identified the bioactive compounds from Semen Torreyae responsible for its anthelmintic activity: galangal acetate and miogadial. The two anthelmintic compounds demonstrated a synergistic effect against C. elegans. Galangal acetate and miogadial are unlikely to act on the targets of currently-used anthelmintics (ivermectin, levamisole, benomyl and aldicarb), and an action on TRP channels appears to be ruled out as well. In summary, galangal acetate and miogadial are promising anthelmintic hits worth further investigation.
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Affiliation(s)
- Maoxuan Liu
- Department of Biology, Animal Physiology and Neurobiology Section, KU Leuven, Naamsestraat 59, box 2465, 3000 Leuven, Belgium; Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Herestraat 49, box 921, 3000 Leuven, Belgium.
| | - Cedrick Veryser
- Department of Chemistry, Molecular Design and Synthesis, KU Leuven, Celestijnenlaan 200F, box 2404, 3000 Leuven, Belgium
| | - Jing-Guang Lu
- State Key Laboratory of Quality Research in Chinese Medicine, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Taipa, Macau 999078, China
| | - Tom Wenseleers
- Department of Ecology, Evolution and Biodiversity Conservation, KU Leuven, Naamsestraat 59, box 2466, 3000 Leuven, Belgium
| | - Wim M De Borggraeve
- Department of Chemistry, Molecular Design and Synthesis, KU Leuven, Celestijnenlaan 200F, box 2404, 3000 Leuven, Belgium
| | - Zhi-Hong Jiang
- State Key Laboratory of Quality Research in Chinese Medicine, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Taipa, Macau 999078, China
| | - Walter Luyten
- Department of Biology, Animal Physiology and Neurobiology Section, KU Leuven, Naamsestraat 59, box 2465, 3000 Leuven, Belgium
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Zheng D, Zeng Z, Xue B, Deng Y, Sun M, Tang YJ, Ruan L. Bacillus thuringiensis produces the lipopeptide thumolycin to antagonize microbes and nematodes. Microbiol Res 2018; 215:22-28. [DOI: 10.1016/j.micres.2018.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 02/23/2018] [Accepted: 06/02/2018] [Indexed: 11/28/2022]
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Whole-Genome Analysis of Bacillus thuringiensis Revealing Partial Genes as a Source of Novel Cry Toxins. Appl Environ Microbiol 2018; 84:AEM.00277-18. [PMID: 29752275 DOI: 10.1128/aem.00277-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 05/05/2018] [Indexed: 12/20/2022] Open
Abstract
Despite the successful application of crystal proteins (Cry) from Bacillus thuringiensis as biological control agents against insects, there is an increasing demand to identify new Cry toxins having higher toxicity and broad-spectrum activity against insects and plant-parasitic nematodes. To find novel Cry toxins, we screened 100 whole-genome sequences of B. thuringiensis Surprisingly, in addition to full Cry toxins, we found partial sequences, such as typical N-terminal or C-terminal regions with conserved domains, widely distributed among 20 strains of B. thuringiensis In order to further elucidate the functions of partial genes, here, we selected a partial sequence from strain C15, having 28% similarity with the N terminus of Cry5Ba and lacking a typical C terminus, and denoted it Cry5B-like N terminus. This fragment when coexpressed as a fusion protein with the C terminus of Cry5Ba (N-C fusion protein) produces pyramidal crystals. A recombinant N-C fusion protein having a 50% lethal concentration (LC50) of 23.7 μg/ml severely affected the life span, growth, and survival rate of nematodes. Light microscopy showed damage to the intestine of nematodes, confirming the pathogenicity of the N-C fusion protein. Last, the green fluorescent protein (GFP)-labeled mutant Caenorhabditis elegans FT63 showed significant damage to the intestine upon feeding N-C fusion toxin compared to the control. These results imply that partial genes can be a source of new Cry toxins, and further understanding about functions of partial cry genes can help in the study of the evolutionary strategy of B. thuringiensis to produce the multidomain toxins.IMPORTANCE Genomic analysis revealed that coding sequences for N termini and C termini of crystal proteins are widely distributed in B. thuringiensis We found Cry5B-like N terminus, lacking typical C terminus, was unable to be expressed in wild-type strain C15. However, its fusion with the C terminus of Cry5Ba not only was successfully expressed but also exhibited activity against the nematodes. This study provides insight into a potential source for novel Cry toxins.
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Hu Y, Miller M, Zhang B, Nguyen TT, Nielsen MK, Aroian RV. In vivo and in vitro studies of Cry5B and nicotinic acetylcholine receptor agonist anthelmintics reveal a powerful and unique combination therapy against intestinal nematode parasites. PLoS Negl Trop Dis 2018; 12:e0006506. [PMID: 29775454 PMCID: PMC5979042 DOI: 10.1371/journal.pntd.0006506] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 05/31/2018] [Accepted: 05/08/2018] [Indexed: 01/21/2023] Open
Abstract
Background The soil-transmitted nematodes (STNs) or helminths (hookworms, whipworms, large roundworms) infect the intestines of ~1.5 billion of the poorest peoples and are leading causes of morbidity worldwide. Only one class of anthelmintic or anti-nematode drugs, the benzimidazoles, is currently used in mass drug administrations, which is a dangerous situation. New anti-nematode drugs are urgently needed. Bacillus thuringiensis crystal protein Cry5B is a powerful, promising new candidate. Drug combinations, when properly made, are ideal for treating infectious diseases. Although there are some clinical trials using drug combinations against STNs, little quantitative and systemic work has been performed to define the characteristics of these combinations in vivo. Methodology/Principal findings Working with the hookworm Ancylostoma ceylanicum-hamster infection system, we establish a laboratory paradigm for studying anti-nematode combinations in vivo using Cry5B and the nicotinic acetylcholine receptor (nAChR) agonists tribendimidine and pyrantel pamoate. We demonstrate that Cry5B strongly synergizes in vivo with both tribendimidine and pyrantel at specific dose ratios against hookworm infections. For example, whereas 1 mg/kg Cry5B and 1 mg/kg tribendimidine individually resulted in only a 0%-6% reduction in hookworm burdens, the combination of the two resulted in a 41% reduction (P = 0.020). Furthermore, when mixed at synergistic ratios, these combinations eradicate hookworm infections at doses where the individual doses do not. Using cyathostomin nematode parasites of horses, we find based on inhibitory concentration 50% values that a strongylid parasite population doubly resistant to nAChR agonists and benzimidazoles is more susceptible or “hypersusceptible” to Cry5B than a cyathostomin population not resistant to nAChR agonists, consistent with previous Caenhorhabditis elegans results. Conclusions/Significance Our study provides a powerful means by which anthelmintic combination therapies can be examined in vivo in the laboratory. In addition, we demonstrate that Cry5B and nAChR agonists have excellent combinatorial properties—Cry5B combined with nAChR agonists gives rise to potent cures that are predicted to be recalcitrant to the development of parasite resistance. These drug combinations highlight bright spots in new anthelmintic development for human and veterinary animal intestinal nematode infections. Intestinal nematodes are roundworm parasites of humans and animals, causing significant morbidity in both. In humans, these parasites are leading causes of morbidity in children, e.g., causing growth stunting, cognitive impairment, and malnutrition. Few drugs are used to treat these parasites in humans and animals and there is increasing evidence that the drugs are losing efficacy and/or have low efficacy. Infectious diseases are best treated with drug combinations and not single drugs. However, there has been little work to characterize in detail how various anti-nematode drugs combine. Here we establish a new laboratory model to study anti-nematode drug combinations using the human hookworm Ancylostoma ceylanicum infection in hamsters. We show that two classes of anti-nematode drugs, Cry5B and the nicotinic acetylcholine receptor agonists tribendimidine and pyrantel, combine (synergize) in a way that is more powerful at specific drug ratios than predicted from their individual impacts. Furthermore, when combined at these ratios, these combinations completely eliminated parasites at doses where normally neither drug has that effect. Horse parasites resistant to pyrantel also appear to be hypersensitive (more sensitive than wild-type parasites) to Cry5B. These characteristics predict that combinations of Cry5B with tribendimidine or pyrantel will be extremely effective therapeutically and relatively recalcitrant to the development of parasite resistance.
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Affiliation(s)
- Yan Hu
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Melanie Miller
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, United States of America
| | - Bo Zhang
- Department of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Thanh-Thanh Nguyen
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Martin K. Nielsen
- Department of Veterinary Science, University of Kentucky, Lexington, KY, United States of America
| | - Raffi V. Aroian
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, United States of America
- * E-mail:
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Bacillus thuringiensis Cry5B protein as a new pan-hookworm cure. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2018; 8:287-294. [PMID: 29772478 PMCID: PMC6039361 DOI: 10.1016/j.ijpddr.2018.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/27/2018] [Accepted: 05/03/2018] [Indexed: 11/20/2022]
Abstract
Hookworms are intestinal nematode parasites that infect nearly half a billion people and are globally one of the most important contributors to iron-deficiency anemia. These parasites have significant impacts in developing children, pregnant women and working adults. Of all the soil-transmitted helminths or nematodes (STNs), hookworms are by far the most important, with disease burdens conservatively estimated at four million DALYs (Disability-Adjusted Life Years) and with productivity losses of up to US$139 billion annually. To date, mainly one drug, albendazole is used for hookworm therapy in mass drug administration, which has on average ∼80% cure rate that is lower (<40%) in some places. Given the massive numbers of people needing treatment, the threat of parasite resistance, and the inadequacy of current treatments, new and better cures against hookworms are urgently needed. Cry5B, a pore-forming protein produced by the soil bacterium Bacillus thuringiensis (Bt) has demonstrated good efficacy against Ancylostoma ceylanicum hookworm infections in hamsters. Here we broaden studies of Cry5B to include tests against infections of Ancylostoma caninum hookworms in dogs and against infections of the dominant human hookworm, Necator americanus, in hamsters. We show that Cry5B is highly effective against all hookworm parasites tested in all models. Neutralization of stomach acid improves Cry5B efficacy, which will aid in practical application of Cry5B significantly. Importantly, we also demonstrate that the anti-nematode therapeutic efficacy of Cry5B is independent of the host immune system and is not itself negated by repeated dosing. This study indicates that Bt Cry5B is a pan-hookworm anthelmintic with excellent properties for use in humans and other animals.
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Strange K. Drug Discovery in Fish, Flies, and Worms. ILAR J 2017; 57:133-143. [PMID: 28053067 DOI: 10.1093/ilar/ilw034] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 10/21/2016] [Indexed: 12/22/2022] Open
Abstract
Nonmammalian model organisms such as the nematode Caenorhabditis elegans, the fruit fly Drosophila melanogaster, and the zebrafish Danio rerio provide numerous experimental advantages for drug discovery including genetic and molecular tractability, amenability to high-throughput screening methods and reduced experimental costs and increased experimental throughput compared to traditional mammalian models. An interdisciplinary approach that strategically combines the study of nonmammalian and mammalian animal models with diverse experimental tools has and will continue to provide deep molecular and genetic understanding of human disease and will significantly enhance the discovery and application of new therapies to treat those diseases. This review will provide an overview of C. elegans, Drosophila, and zebrafish biology and husbandry and will discuss how these models are being used for phenotype-based drug screening and for identification of drug targets and mechanisms of action. The review will also describe how these and other nonmammalian model organisms are uniquely suited for the discovery of drug-based regenerative medicine therapies.
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Affiliation(s)
- Kevin Strange
- Kevin Strange, Ph.D., is President and CEO of the MDI Biological Laboratory and CEO of Novo Biosciences, Inc
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Ding X, Njus Z, Kong T, Su W, Ho CM, Pandey S. Effective drug combination for Caenorhabditis elegans nematodes discovered by output-driven feedback system control technique. SCIENCE ADVANCES 2017; 3:eaao1254. [PMID: 28983514 PMCID: PMC5627981 DOI: 10.1126/sciadv.aao1254] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 09/13/2017] [Indexed: 02/05/2023]
Abstract
Infections from parasitic nematodes (or roundworms) contribute to a significant disease burden and productivity losses for humans and livestock. The limited number of anthelmintics (or antinematode drugs) available today to treat these infections are rapidly losing their efficacy as multidrug resistance in parasites becomes a global health challenge. We propose an engineering approach to discover an anthelmintic drug combination that is more potent at killing wild-type Caenorhabditis elegans worms than four individual drugs. In the experiment, freely swimming single worms are enclosed in microfluidic drug environments to assess the centroid velocity and track curvature of worm movements. After analyzing the behavioral data in every iteration, the feedback system control (FSC) scheme is used to predict new drug combinations to test. Through a differential evolutionary search, the winning drug combination is reached that produces minimal centroid velocity and high track curvature, while requiring each drug in less than their EC50 concentrations. The FSC approach is model-less and does not need any information on the drug pharmacology, signaling pathways, or animal biology. Toward combating multidrug resistance, the method presented here is applicable to the discovery of new potent combinations of available anthelmintics on C. elegans, parasitic nematodes, and other small model organisms.
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Affiliation(s)
- Xianting Ding
- State Key Laboratory of Oncogenes and Related Genes, Institute for Personalized Medicine, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Zach Njus
- Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011, USA
| | - Taejoon Kong
- Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011, USA
| | - Wenqiong Su
- State Key Laboratory of Oncogenes and Related Genes, Institute for Personalized Medicine, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Chih-Ming Ho
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Santosh Pandey
- Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011, USA
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The novel nematicide wact-86 interacts with aldicarb to kill nematodes. PLoS Negl Trop Dis 2017; 11:e0005502. [PMID: 28379972 PMCID: PMC5393889 DOI: 10.1371/journal.pntd.0005502] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 04/17/2017] [Accepted: 03/18/2017] [Indexed: 11/19/2022] Open
Abstract
Parasitic nematodes negatively impact human and animal health worldwide. The market withdrawal of nematicidal agents due to unfavourable toxicities has limited the available treatment options. In principle, co-administering nematicides at lower doses along with molecules that potentiate their activity could mitigate adverse toxicities without compromising efficacy. Here, we screened for new small molecules that interact with aldicarb, which is a highly effective treatment for plant-parasitic nematodes whose toxicity hampers its utility. From our collection of 638 worm-bioactive compounds, we identified 20 molecules that interact positively with aldicarb to either kill or arrest the growth of the model nematode Caenorhabditis elegans. We investigated the mechanism of interaction between aldicarb and one of these novel nematicides called wact-86. We found that the carboxylesterase enzyme GES-1 hydrolyzes wact-86, and that the interaction is manifested by aldicarb’s inhibition of wact-86’s metabolism by GES-1. This work demonstrates the utility of C. elegans as a platform to search for new molecules that can positively interact with industrial nematicides, and provides proof-of-concept for prospective discovery efforts. Many nematicides that have been used to kill plant and animal parasitic nematodes are being phased out over concerns of toxicity to humans. One potential solution to reduce toxicity is to use the nematicide at a lower concentration in combination with a second compound that together will produce a synergistic killing effect. That is, the use of either molecule alone at low concentrations is non-lethal, but when used together at these same concentrations, the cocktail is lethal. This strategy has two benefits. First, the killing effect is concentrated at the site of use and as the two molecules diffuse from the targeted site, toxicity is negated. Second, less of the toxic molecule is needed and therefore less is dispersed into the environment. Here, we describe our use of a model nematode called C. elegans to search for molecules that interact with aldicarb, which is one of the nematicides being phased out by environmental agencies. We identified 20 compounds that interact with aldicarb and describe how one of these, called wact-86, functions with aldicarb to kill worms. Our work provides proof-of-principle that C. elegans is a useful model for identifying compounds that positively interact with industrial nematicides and for understanding the nature of such interactions.
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Matthews H, Deakin J, Rajab M, Idris-Usman M, Nirmalan NJ. Investigating antimalarial drug interactions of emetine dihydrochloride hydrate using CalcuSyn-based interactivity calculations. PLoS One 2017; 12:e0173303. [PMID: 28257497 PMCID: PMC5336292 DOI: 10.1371/journal.pone.0173303] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 02/17/2017] [Indexed: 11/18/2022] Open
Abstract
The widespread introduction of artemisinin-based combination therapy has contributed to recent reductions in malaria mortality. Combination therapies have a range of advantages, including synergism, toxicity reduction, and delaying the onset of resistance acquisition. Unfortunately, antimalarial combination therapy is limited by the depleting repertoire of effective drugs with distinct target pathways. To fast-track antimalarial drug discovery, we have previously employed drug-repositioning to identify the anti-amoebic drug, emetine dihydrochloride hydrate, as a potential candidate for repositioned use against malaria. Despite its 1000-fold increase in in vitro antimalarial potency (ED50 47 nM) compared with its anti-amoebic potency (ED50 26–32 uM), practical use of the compound has been limited by dose-dependent toxicity (emesis and cardiotoxicity). Identification of a synergistic partner drug would present an opportunity for dose-reduction, thus increasing the therapeutic window. The lack of reliable and standardised methodology to enable the in vitro definition of synergistic potential for antimalarials is a major drawback. Here we use isobologram and combination-index data generated by CalcuSyn software analyses (Biosoft v2.1) to define drug interactivity in an objective, automated manner. The method, based on the median effect principle proposed by Chou and Talalay, was initially validated for antimalarial application using the known synergistic combination (atovaquone-proguanil). The combination was used to further understand the relationship between SYBR Green viability and cytocidal versus cytostatic effects of drugs at higher levels of inhibition. We report here the use of the optimised Chou Talalay method to define synergistic antimalarial drug interactivity between emetine dihydrochloride hydrate and atovaquone. The novel findings present a potential route to harness the nanomolar antimalarial efficacy of this affordable natural product.
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Affiliation(s)
- Holly Matthews
- Environment and Life sciences, University of Salford, Greater Manchester, United Kingdom
| | - Jon Deakin
- Environment and Life sciences, University of Salford, Greater Manchester, United Kingdom
| | - May Rajab
- Environment and Life sciences, University of Salford, Greater Manchester, United Kingdom
| | - Maryam Idris-Usman
- Environment and Life sciences, University of Salford, Greater Manchester, United Kingdom
| | - Niroshini J. Nirmalan
- Environment and Life sciences, University of Salford, Greater Manchester, United Kingdom
- * E-mail:
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Du C, Cao S, Shi X, Nie X, Zheng J, Deng Y, Ruan L, Peng D, Sun M. Genetic and Biochemical Characterization of a Gene Operon for trans-Aconitic Acid, a Novel Nematicide from Bacillus thuringiensis. J Biol Chem 2017; 292:3517-3530. [PMID: 28087696 DOI: 10.1074/jbc.m116.762666] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 12/31/2016] [Indexed: 12/31/2022] Open
Abstract
trans-Aconitic acid (TAA) is an isomer of cis-aconitic acid (CAA), an intermediate of the tricarboxylic acid cycle that is synthesized by aconitase. Although TAA production has been detected in bacteria and plants for many years and is known to be a potent inhibitor of aconitase, its biosynthetic origins and the physiological relevance of its activity have remained unclear. We have serendipitously uncovered key information relevant to both of these questions. Specifically, in a search for novel nematicidal factors from Bacillus thuringiensis, a significant nematode pathogen harboring many protein virulence factors, we discovered a high yielding component that showed activity against the plant-parasitic nematode Meloidogyne incognita and surprisingly identified it as TAA. Comparison with CAA, which displayed a much weaker nematicidal effect, suggested that TAA is specifically synthesized by B. thuringiensis as a virulence factor. Analysis of mutants deficient in plasmids that were anticipated to encode virulence factors allowed us to isolate a TAA biosynthesis-related (tbr) operon consisting of two genes, tbrA and tbrB We expressed the corresponding proteins, TbrA and TbrB, and characterized them as an aconitate isomerase and TAA transporter, respectively. Bioinformatics analysis of the TAA biosynthetic gene cluster revealed the association of the TAA genes with transposable elements relevant for horizontal gene transfer as well as a distribution across B. cereus bacteria and other B. thuringiensis strains, suggesting a general role for TAA in the interactions of B. cereus group bacteria with nematode hosts in the soil environment. This study reveals new bioactivity for TAA and the TAA biosynthetic pathway, improving our understanding of virulence factors employed by B. thuringiensis pathogenesis and providing potential implications for nematode management applications.
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Affiliation(s)
- Cuiying Du
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Shiyun Cao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xiangyu Shi
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xiangtao Nie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jinshui Zheng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yun Deng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Lifang Ruan
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Donghai Peng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
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Loukas A, Hotez PJ, Diemert D, Yazdanbakhsh M, McCarthy JS, Correa-Oliveira R, Croese J, Bethony JM. Hookworm infection. Nat Rev Dis Primers 2016; 2:16088. [PMID: 27929101 DOI: 10.1038/nrdp.2016.88] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Hookworms are soil-transmitted nematode parasites that can reside for many years in the small intestine of their human hosts; Necator americanus is the predominant infecting species. Adult worms feed on the blood of a host and can cause iron deficiency anaemia, especially in high-risk populations (children and women of childbearing age). Almost 500 million people in developing tropical countries are infected, and simulation models estimate that hookworm infection is responsible for >4 million disability-adjusted life years lost annually. Humans mount an immune response to hookworms, but it is mostly unsuccessful at removing adult worms from the bowel. Accordingly, the host switches to an immune-tolerant state that enables hookworms to reside in the gut for many years. Although anthelmintic drugs are available and widely used, their efficacy varies and the drugs do not prevent reinfection. Thus, other control strategies aimed at improving water quality, sanitation and hygiene are needed. In addition, efforts are underway to develop a human hookworm vaccine through public-private partnerships. However, hookworms could also be a resource; as hookworms have the capability to regulate the host's inflammation, researchers are experimentally infecting patients to treat some inflammatory diseases as an approach to discover new anti-inflammatory molecules. This area of endeavour might well yield new biotherapeutics for autoimmune and allergic diseases.
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Affiliation(s)
- Alex Loukas
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, Building E4, James Cook University, McGregor Rd, Smithfield, Cairns, Queensland 4878, Australia
| | - Peter J Hotez
- Departments of Pediatrics and Molecular Virology and Microbiology, National School of Tropical Medicine, Baylor College Of Medicine, Houston, Texas, USA.,Sabin Vaccine Institute, Houston, Texas, USA.,Texas Children's Hospital Center for Vaccine Development, Houston, Texas, USA
| | - David Diemert
- Department of Microbiology, Tropical Medicine and Immunology, George Washington University, Washington DC, USA.,Sabin Vaccine Institute, Washington DC, USA
| | - Maria Yazdanbakhsh
- Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands
| | - James S McCarthy
- Queensland Institute of Medical Research (QIMR) Berghofer Medical Research Institute, Brisbane, Queensland, Australia.,University of Queensland, Brisbane, Queensland, Australia
| | | | - John Croese
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, Building E4, James Cook University, McGregor Rd, Smithfield, Cairns, Queensland 4878, Australia.,Department of Gastroenterology, Prince Charles Hospital, Brisbane, Queensland, Australia
| | - Jeffrey M Bethony
- Department of Microbiology, Tropical Medicine and Immunology, George Washington University, Washington DC, USA
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Ramos F, Portella LP, Rodrigues FDS, Reginato CZ, Pötter L, Cezar AS, Sangioni LA, Vogel FSF. Anthelmintic resistance in gastrointestinal nematodes of beef cattle in the state of Rio Grande do Sul, Brazil. Int J Parasitol Drugs Drug Resist 2016; 6:93-101. [PMID: 27054068 PMCID: PMC4805775 DOI: 10.1016/j.ijpddr.2016.02.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 02/01/2016] [Accepted: 02/05/2016] [Indexed: 01/27/2023]
Abstract
Gastrointestinal nematodes resistant to anthelmintics have been reported in several regions of Brazil, and they may be associated with economic losses for the cattle industry. This study aimed to evaluate the resistance status of gastrointestinal nematodes from naturally infected beef cattle to several commercially available anthelmintics, as well as to test the efficacy of combinations of anthelmintics against multi-resistant gastrointestinal nematodes. Ten farms located in Rio Grande do Sul state were selected by: farmers' consent; extensive raising system; availability of calves aged from 7 to 9 months naturally infected by gastrointestinal nematodes; absence of anthelmintic treatment for 60 days before the study; and presence of 70-100 calves or more of both genders with ≥ 200 eggs per gram of feces (EPG) (sensitivity of 50 EPG). These calves were distributed into 10 groups (of 7-10 animals) per farm and treated with ivermectin, doramectin, eprinomectin, fenbendazole, closantel, nitroxynil, disophenol, levamisole, albendazole, or moxidectin. Feces were collected 2 days before treatment and 14 days after treatment. Additional groups of 7-10 calves were used to test six different two-drug combinations at four of the studied farms. In general terms, fenbendazole was the most effective drug, followed by levamisole, disophenol, and moxidectin. However, parasite resistance to multiple drugs was found in all herds, especially in the genera Cooperia spp., Trichostrongylus spp., and Haemonchus spp.. Some of the two-drug combinations were effective against nematode populations identified as resistant to the same compounds when used as single drugs. The most effective combinations were moxidectin + levamisole, doramectin + fenbendazole, and levamisole + closantel. In this study, parasites resistant to the main commercially available anthelmintics were found in all herds, and some combinations of two active components belonging to different chemical groups were effective against multi-drug resistant gastrointestinal nematodes.
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Affiliation(s)
- Fernanda Ramos
- Departamento de Medicina Veterinária Preventiva (DMVP), Centro de Ciências Rurais (CCR), Universidade Federal de Santa Maria (UFSM), 97105-900, Santa Maria, RS, Brazil.
| | - Luiza Pires Portella
- Departamento de Medicina Veterinária Preventiva (DMVP), Centro de Ciências Rurais (CCR), Universidade Federal de Santa Maria (UFSM), 97105-900, Santa Maria, RS, Brazil
| | - Fernando de Souza Rodrigues
- Departamento de Medicina Veterinária Preventiva (DMVP), Centro de Ciências Rurais (CCR), Universidade Federal de Santa Maria (UFSM), 97105-900, Santa Maria, RS, Brazil
| | - Caroline Zamperete Reginato
- Departamento de Medicina Veterinária Preventiva (DMVP), Centro de Ciências Rurais (CCR), Universidade Federal de Santa Maria (UFSM), 97105-900, Santa Maria, RS, Brazil
| | - Luciana Pötter
- Departamento de Zootecnia, UFSM, Santa Maria, RS, Brazil
| | - Alfredo Skrebsky Cezar
- Departamento de Medicina Veterinária Preventiva (DMVP), Centro de Ciências Rurais (CCR), Universidade Federal de Santa Maria (UFSM), 97105-900, Santa Maria, RS, Brazil; Programa de Pós-Graduação em Economia e Desenvolvimento, PNPD/CAPES, UFSM, Santa Maria, RS, Brazil
| | - Luís Antônio Sangioni
- Departamento de Medicina Veterinária Preventiva (DMVP), Centro de Ciências Rurais (CCR), Universidade Federal de Santa Maria (UFSM), 97105-900, Santa Maria, RS, Brazil
| | - Fernanda Silveira Flores Vogel
- Departamento de Medicina Veterinária Preventiva (DMVP), Centro de Ciências Rurais (CCR), Universidade Federal de Santa Maria (UFSM), 97105-900, Santa Maria, RS, Brazil
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Campbell SJ, Nery SV, McCarthy JS, Gray DJ, Soares Magalhães RJ, Clements ACA. A Critical Appraisal of Control Strategies for Soil-Transmitted Helminths. Trends Parasitol 2016; 32:97-107. [PMID: 26795294 DOI: 10.1016/j.pt.2015.10.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 10/10/2015] [Accepted: 10/13/2015] [Indexed: 12/29/2022]
Abstract
Interventions that lead to reductions in soil-transmitted helminths (STHs) include chemotherapy with anthelmintic drugs and improvements in water, sanitation, and hygiene (WASH). In this opinion article we aim to determine the evidence for optimal approaches for STH control. First we explore the evidence for the above interventions. We then appraise two integration strategies: current chemotherapy-oriented integrated neglected tropical disease (NTD) control and expanded 'multicomponent integration', which includes integrated chemotherapy, WASH, and other intervention strategies. While multicomponent integrated control may be an effective approach to sustainably reduce STH transmission, there is a need for evidence to prove the feasibility of this approach.
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Affiliation(s)
- Suzy J Campbell
- Research School of Population Health, College of Medicine, Biology, and Environment, The Australian National University, Canberra, Australia.
| | - Susana V Nery
- Research School of Population Health, College of Medicine, Biology, and Environment, The Australian National University, Canberra, Australia
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, Australia; School of Public Health, University of Queensland, Brisbane, Australia
| | - Darren J Gray
- Research School of Population Health, College of Medicine, Biology, and Environment, The Australian National University, Canberra, Australia; QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Ricardo J Soares Magalhães
- Children's Health and Environment Program, Queensland Children's Medical Research Institute, University of Queensland, Brisbane, Australia; School of Veterinary Science, University of Queensland, Gatton, Australia
| | - Archie C A Clements
- Research School of Population Health, College of Medicine, Biology, and Environment, The Australian National University, Canberra, Australia
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Intracellular and Extracellular Expression of Bacillus thuringiensis Crystal Protein Cry5B in Lactococcus lactis for Use as an Anthelminthic. Appl Environ Microbiol 2015; 82:1286-94. [PMID: 26682852 PMCID: PMC4751831 DOI: 10.1128/aem.02365-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/22/2015] [Indexed: 12/20/2022] Open
Abstract
The Bacillus thuringiensis crystal (Cry) protein Cry5B (140 kDa) and a truncated version of the protein, tCry5B (79 kDa), are lethal to nematodes. Genes encoding the two proteins were separately cloned into a high-copy-number vector with a strong constitutive promoter (pTRK593) in Lactococcus lactis for potential oral delivery against parasitic nematode infections. Western blots using a Cry5B-specific antibody revealed that constitutively expressed Cry5B and tCry5B were present in both cells and supernatants. To increase production, cry5B was cloned into the high-copy-number plasmid pMSP3535H3, carrying a nisin-inducible promoter. Immunoblotting revealed that 3 h after nisin induction, intracellular Cry5B was strongly induced at 200 ng/ml nisin, without adversely affecting cell viability or cell membrane integrity. Both Cry5B genes were also cloned into plasmid pTRK1061, carrying a promoter and encoding a transcriptional activator that invoke low-level expression of prophage holin and lysin genes in Lactococcus lysogens, resulting in a leaky phenotype. Cry5B and tCry5B were actively expressed in the lysogenic strain L. lactis KP1 and released into cell supernatants without affecting culture growth. Lactate dehydrogenase (LDH) assays indicated that Cry5B, but not LDH, leaked from the bacteria. Lastly, using intracellular lysates from L. lactis cultures expressing both Cry5B and tCry5B, in vivo challenges of Caenorhabditis elegans worms demonstrated that the Cry proteins were biologically active. Taken together, these results indicate that active Cry5B proteins can be expressed intracellularly in and released extracellularly from L. lactis, showing potential for future use as an anthelminthic that could be delivered orally in a food-grade microbe.
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Ruan L, Crickmore N, Peng D, Sun M. Are nematodes a missing link in the confounded ecology of the entomopathogen Bacillus thuringiensis? Trends Microbiol 2015; 23:341-6. [DOI: 10.1016/j.tim.2015.02.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Revised: 01/29/2015] [Accepted: 02/25/2015] [Indexed: 01/23/2023]
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36
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Buxton SK, Robertson AP, Martin RJ. Diethylcarbamazine increases activation of voltage-activated potassium (SLO-1) currents in Ascaris suum and potentiates effects of emodepside. PLoS Negl Trop Dis 2014; 8:e3276. [PMID: 25411836 PMCID: PMC4238981 DOI: 10.1371/journal.pntd.0003276] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 09/17/2014] [Indexed: 12/14/2022] Open
Abstract
Diethylcarbamazine is a drug that is used for the treatment of filariasis in humans and animals; it also has effects on intestinal nematodes, but its mechanism of action remains unclear. Emodepside is a resistance-busting anthelmintic approved for treating intestinal parasitic nematodes in animals. The novel mode of action and resistance-breaking properties of emodepside has led to its use against intestinal nematodes of animals, and as a candidate drug for treating filarial parasites. We have previously demonstrated effects of emodepside on SLO-1 K+-like currents in Ascaris suum. Here, we demonstrate that diethylcarbamazine, which has been proposed to work through host mediated effects, has direct effects on a nematode parasite, Ascaris suum. It increases activation of SLO-1 K+ currents and potentiates effects of emodepside. Our results suggest consideration of the combination of emodepside and diethylcarbamazine for therapy, which is predicted to be synergistic. The mode of action of diethylcarbamazine may involve effects on parasite signaling pathways (including nitric oxide) as well as effects mediated by host inflammatory mediators. Filarial parasites and soil-transmitted nematodes (STNs) are Neglected Tropical Diseases (NTDs) that affect millions of people in the developing world. There is an urgent need for novel drugs and improved use of existing drugs, because of concerns about the development of resistance. The mode of action of one of these drugs, diethylcarbamazine, remains unclear, despite the fact that it has been used for a long time for treatment and prevention of filariae and STNs. The resistance-busting anthelmintic emodepside also has effects against filariae and STNs, with a mode of action that involves activation of nematode SLO-1 K+ channels. The effects of both diethylcarbamazine and emodepside may be increased by inflammatory mediators, which suggests that the effects of diethylcarbamazine and emodepside will be additive. We used our Ascaris suum preparation to test the activation of SLO-1 K+ channels by diethylcarbamazine and its potentiating effect on emodepside. Our results suggest potential for diethylcarbamazine and emodepside in combination therapy for parasitic nematodes.
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Affiliation(s)
- Samuel K. Buxton
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Alan P. Robertson
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Richard J. Martin
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
- * E-mail:
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Greenberg RM. Schistosome ABC multidrug transporters: From pharmacology to physiology. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2014; 4:301-9. [PMID: 25516841 PMCID: PMC4266782 DOI: 10.1016/j.ijpddr.2014.09.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The genuine and hypothesized roles of schistosome ABC transporters are reviewed. Evidence suggesting a role for transporters in schistosome drug susceptibility is discussed. Potential roles of ABC transporters in normal schistosome biology are outlined.
Praziquantel (PZQ) is essentially the only drug currently available for treatment and control of schistosomiasis, a disease affecting hundreds of millions worldwide. Though highly effective overall, PZQ has limitations, most notably its significant lack of activity against immature schistosomes. Furthermore, the availability of only a single drug for a disease of this magnitude makes reports of PZQ-resistant isolates particularly troubling. ATP-binding cassette (ABC) multidrug transporters such as P-glycoprotein (Pgp; ABCB1) are efflux transporters that underlie multidrug resistance (MDR); changes in their expression or structure are also associated with drug resistance in parasites, including helminths. This review will discuss the role these transporters might play in modulating schistosome susceptibility to PZQ, and the implications for developing new or repurposed treatments that enhance the efficacy of PZQ. However, in addition to influencing drug susceptibility, ABC transporters play important roles in several critical physiological functions such as excretion and maintenance of permeability barriers. They also transport signaling molecules with high affinity, and several lines of evidence implicate mammalian transporters in a diverse array of physiological functions, including regulation of immune responses. Like their mammalian counterparts, schistosome ABC transporters appear to be involved in functions critical to the parasite, including excretory activity and reproduction, and we hypothesize that they underlie at least some aspects of parasite–host interactions. Thus, in addition to their potential as targets for enhancers of PZQ susceptibility, these transporters might also serve as candidate targets for agents that disrupt the parasite life cycle and act as antischistosomals on their own.
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Affiliation(s)
- Robert M Greenberg
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, PA 19104, USA
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Somvanshi VS, Ellis BL, Hu Y, Aroian RV. Nitazoxanide: nematicidal mode of action and drug combination studies. Mol Biochem Parasitol 2014; 193:1-8. [PMID: 24412397 PMCID: PMC3972318 DOI: 10.1016/j.molbiopara.2013.12.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 12/03/2013] [Accepted: 12/17/2013] [Indexed: 11/18/2022]
Abstract
Intestinal nematodes or roundworms (aka soil-transmitted helminths or STHs) cause great disease. They infect upwards of two billion people, leading to high morbidity and a range of health problems, especially in infected children and pregnant women. Development of resistance to the two main classes of drugs used to treat intestinal nematode infections of humans has been reported. To fight STH infections, we need new and more effective drugs and ways to improve the efficacy of the old drugs. One promising alternative drug is nitazoxanide (NTZ). NTZ, approved for treating human protozoan infections, was serendipitously shown to have therapeutic activity against STHs. However, its mechanism of action against nematodes is not known. Using the laboratory nematode Caenorhabditis elegans, we show that NTZ acts on the nematodes through avr-14, an alpha-type subunit of a glutamate-gated chloride ion channel known for its role in ivermectin susceptibility. In addition, a forward genetic screen to select C. elegans mutants resistant to NTZ resulted in isolation of two NTZ resistant mutants that are not in avr-14, suggesting that additional mechanisms are involved in resistance to NTZ. We found that NTZ combines synergistically with other classes of anthelmintic drugs, i.e. albendazole and pyrantel, making it a good candidate for further studies on its use in drug combination therapy of STH infections. Given NTZ acts against a wide range of nematode parasites, our findings also validate avr-14 as an excellent target for pan-STH therapy.
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Affiliation(s)
- Vishal S Somvanshi
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Brian L Ellis
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Yan Hu
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Raffi V Aroian
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California San Diego, La Jolla, CA, USA.
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Lycke R, Parashar A, Pandey S. Microfluidics-enabled method to identify modes of Caenorhabditis elegans paralysis in four anthelmintics. BIOMICROFLUIDICS 2013; 7:64103. [PMID: 24396537 DOI: 10.1063/1.4829777] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 10/29/2013] [Indexed: 02/05/2023]
Abstract
The discovery of new drugs is often propelled by the increasing resistance of parasites to existing drugs and the availability of better technology platforms. The area of microfluidics has provided devices for faster screening of compounds, controlled sampling/sorting of whole animals, and automated behavioral pattern recognition. In most microfluidic devices, drug effects on small animals (e.g., Caenorhabditis elegans) are quantified by an end-point, dose response curve representing a single parameter (such as worm velocity or stroke frequency). Here, we present a multi-parameter extraction method to characterize modes of paralysis in C. elegans over an extended time period. A microfluidic device with real-time imaging is used to expose C. elegans to four anthelmintic drugs (i.e., pyrantel, levamisole, tribendimidine, and methyridine). We quantified worm behavior with parameters such as curls per second, types of paralyzation, mode frequency, and number/duration of active/immobilization periods. Each drug was chosen at EC75 where 75% of the worm population is responsive to the drug. At equipotent concentrations, we observed differences in the manner with which worms paralyzed in drug environments. Our study highlights the need for assaying drug effects on small animal models with multiple parameters quantified at regular time points over an extended period to adequately capture the resistance and adaptability in chemical environments.
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Affiliation(s)
- Roy Lycke
- Departments of Biological Sciences & Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
| | - Archana Parashar
- Department of Electrical & Computer Engineering, Iowa State University, Ames, Iowa 50011, USA
| | - Santosh Pandey
- Department of Electrical & Computer Engineering, Iowa State University, Ames, Iowa 50011, USA
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Arvanitis M, Glavis-Bloom J, Mylonakis E. C. elegans for anti-infective discovery. Curr Opin Pharmacol 2013; 13:769-74. [DOI: 10.1016/j.coph.2013.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 07/09/2013] [Accepted: 08/04/2013] [Indexed: 11/30/2022]
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Bacillus subtilis strain engineered for treatment of soil-transmitted helminth diseases. Appl Environ Microbiol 2013; 79:5527-32. [PMID: 23835175 DOI: 10.1128/aem.01854-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Soil-transmitted helminths (hookworms, whipworms, and large roundworms) are agents of intestinal roundworm diseases of poverty that infect upwards of 2 billion people worldwide. A great challenge in treating these diseases is the development of anthelmintic therapeutics that are inexpensive, can be produced in great quantity, and are capable of delivery under varied and adverse environmental conditions. A potential solution to this challenge is the use of live bacteria that are acceptable for human consumption, e.g., Bacillus subtilis, and that can be engineered with therapeutic properties. In this study, we expressed the Bacillus thuringiensis anthelmintic protein Cry5B in a bacterial strain that has been used as a model for live bacterial therapy, Bacillus subtilis PY79. PY79 transformed with a Cry5B expression plasmid (PY79-Cry5B) is able to express Cry5B from the endogenous B. thuringiensis cry5B promoter. During sporulation of PY79-Cry5B, Cry5B is packaged as a crystal. Furthermore, Cry5B produced in PY79 is bioactive, with a 50% lethal concentration (LC50) of 4.3 μg/ml against the roundworm Caenorhabditis elegans. PY79-Cry5B was a significantly effective therapeutic in experimental Ancylostoma ceylanicum hookworm infections of hamsters. A single 10-mg/kg (0.071 μmol/kg of body weight) dose of Cry5B administered as a Cry5B-PY79 spore crystal lysate achieved a 93% reduction in hookworm burdens, which is superior on a molar level to reductions seen with clinically used anthelmintics. Given that a bacterial strain such as this one can be produced cheaply in massive quantities, our results demonstrate that the engineering and delivery of live bacterial strains have great potential to treat a significant contributor to poverty worldwide, namely, hookworm disease and other soil-transmitted helminthiasis.
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Urban JF, Hu Y, Miller MM, Scheib U, Yiu YY, Aroian RV. Bacillus thuringiensis-derived Cry5B has potent anthelmintic activity against Ascaris suum. PLoS Negl Trop Dis 2013; 7:e2263. [PMID: 23818995 PMCID: PMC3688533 DOI: 10.1371/journal.pntd.0002263] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 04/27/2013] [Indexed: 11/18/2022] Open
Abstract
Ascaris suum and Ascaris lumbricoides are two closely related geo-helminth parasites that ubiquitously infect pigs and humans, respectively. Ascaris suum infection in pigs is considered a good model for A. lumbricoides infection in humans because of a similar biology and tissue migration to the intestines. Ascaris lumbricoides infections in children are associated with malnutrition, growth and cognitive stunting, immune defects, and, in extreme cases, life-threatening blockage of the digestive tract and aberrant migration into the bile duct and peritoneum. Similar effects can be seen with A. suum infections in pigs related to poor feed efficiency and performance. New strategies to control Ascaris infections are needed largely due to reduced treatment efficacies of current anthelmintics in the field, the threat of resistance development, and the general lack of new drug development for intestinal soil-transmitted helminths for humans and animals. Here we demonstrate for the first time that A. suum expresses the receptors for Bacillus thuringiensis crystal protein and novel anthelmintic Cry5B, which has been previously shown to intoxicate hookworms and which belongs to a class of proteins considered non-toxic to vertebrates. Cry5B is able to intoxicate A. suum larvae and adults and triggers the activation of the p38 mitogen-activated protein kinase pathway similar to that observed with other nematodes. Most importantly, two moderate doses of 20 mg/kg body weight (143 nM/kg) of Cry5B resulted in a near complete cure of intestinal A. suum infections in pigs. Taken together, these results demonstrate the excellent potential of Cry5B to treat Ascaris infections in pigs and in humans and for Cry5B to work effectively in the human gastrointestinal tract. Ascaris suum is an intestinal parasitic nematode of pigs that is very closely related to Ascaris lumbricoides, a major intestinal parasitic nematode of humans that infects more than one billion people worldwide. Because of reduced efficacy and the threat of resistance to the current small set of approved drugs to treat Ascaris infections, new treatments are needed. Here we test against A. suum infections the effectiveness of Cry5B, a nematode-killing protein made by the natural soil bacterium Bacillus thuringiensis and representing a promising new class of anthelmintics. We demonstrate for the first time that A. suum possesses the receptors to bind Cry5B and that Cry5B can kill A. suum larvae and adults in culture. Most importantly, we demonstrate that oral administration of Cry5B to pigs infected with A. suum larvae results in a near complete elimination of the infection. Given the similarities between A. suum and A. lumbricoides and the similarity between the pig and human gastrointestinal tracts, our data indicate that Cry5B has excellent potential to treat Ascaris infections in veterinary animals and in humans.
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Affiliation(s)
- Joseph F. Urban
- USDA, Agricultural Research Service, Beltsville Human Nutrition Research Center, Diet, Genomics, and Immunology Laboratory, Beltsville, Maryland, United States of America
| | - Yan Hu
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Melanie M. Miller
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Ulrike Scheib
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Ying Y. Yiu
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Raffi V. Aroian
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America
- * E-mail:
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Miltsch SM, Krücken J, Demeler J, Ramünke S, Harder A, von Samson-Himmelstjerna G. Interactions of anthelmintic drugs in Caenorhabditis elegans neuro-muscular ion channel mutants. Parasitol Int 2013; 62:591-8. [PMID: 23707730 DOI: 10.1016/j.parint.2013.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 05/13/2013] [Accepted: 05/14/2013] [Indexed: 11/29/2022]
Abstract
Due to the increasing development of anthelmintic resistance in nematodes worldwide, it is important to search for anthelmintic compounds with new modes of action and also to investigate the possibility to combine compounds with possible synergistic effects. There might also be the chance to take advantage of the fact that nematode populations which have developed resistance against one anthelmintic class might respond hypersusceptibly to another drug class. The aim of this study was to investigate responses of Caenorhabditis elegans populations with mutations in neuro-muscular ion channels to different anthelmintic classes. Furthermore, potential synergistic effects between two anthelmintic compounds from different classes, i.e. emodepside and tribendimidine, were studied. Although there was neither a synergistic nor an antagonistic effect between emodepside and tribendimidine, other types of interactions could be identified. The C. elegans GABAA-receptor (GABAA-R) unc-49 mutants, showing decreased emodepside susceptibility, were more susceptible to tribendimidine than wild-type C. elegans. In contrast, the reverse phenomenon - hypersusceptibility to emodepside in tribendimidine resistant acetylcholine-receptor (AChR) loss of function mutants - was not observed. Moreover, the slo-1 mutant strain (completely emodepside resistant) also showed hypersusceptibility to piperazine. Interestingly, neither the GABAA-R unc-49 mutants nor the AChR mutants showed decreased susceptibility against piperazine, although there were some studies that indicated an involvement of GABAA-R or AChR in the piperazine mode of action. In conclusion, the present study provides evidence suggesting that interactions between commercially available anthelmintic drugs with different modes of action might be a relatively common phenomenon but this has to be carefully worked out for each anthelmintic and each anthelmintic drug combination. Moreover, results obtained in C. elegans will have to be confirmed using parasitic nematodes in the future.
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Affiliation(s)
- Sandra M Miltsch
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
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Current drug targets for helminthic diseases. Parasitol Res 2013; 112:1819-31. [PMID: 23529336 DOI: 10.1007/s00436-013-3383-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 03/05/2013] [Indexed: 01/08/2023]
Abstract
More than 2 billion people are infected with helminth parasites across the globe. The burgeoning drug resistance against current anthelmintics in parasitic worms of humans and livestock requires urgent attention to tackle these recalcitrant worms. This review focuses on the advancements made in the area of helminth drug target discovery especially from the last few couple of decades. It highlights various approaches made in this field and enlists the potential drug targets currently being pursued to target economically important helminth species both from human as well as livestock to combat disease pathology of schistosomiasis, onchocerciasis, lymphatic filariasis, and other important macroparasitic diseases. Research in the helminths study is trending to identify potential and druggable targets through genomic, proteomic, biochemical, biophysical, in vitro experiments, and in vivo experiments in animal models. The availability of major helminths genome sequences and the subsequent availability of genome-scale functional datasets through in silico search and prioritization are expected to guide the experimental work necessary for target-based drug discovery. Organized and documented list of drug targets from various helminths of economic importance have been systematically covered in this review for further exploring their use and applications, which can give physicians and veterinarians effective drugs in hand to enable them control worm infections.
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Greenberg RM. ABC multidrug transporters in schistosomes and other parasitic flatworms. Parasitol Int 2013; 62:647-53. [PMID: 23474413 DOI: 10.1016/j.parint.2013.02.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 02/14/2013] [Accepted: 02/18/2013] [Indexed: 12/19/2022]
Abstract
Schistosomiasis, a neglected tropical disease affecting hundreds of millions, is caused by parasitic flatworms of the genus Schistosoma. Treatment and control of schistosomiasis relies almost exclusively on a single drug, praziquantel (PZQ), a dangerous situation for a disease of this magnitude. Though PZQ is highly effective overall, it has drawbacks, and reports of worms showing PZQ resistance, either induced in the laboratory or isolated from the field, are disconcerting. Multidrug transporters underlie multidrug resistance (MDR), a phenomenon in which resistance to a single drug is accompanied by unexpected cross-resistance to several structurally unrelated compounds. Some of the best studied multidrug transporters are members of the ancient and very large ATP-binding cassette (ABC) superfamily of efflux transporters. ABC multidrug transporters such as P-glycoprotein (Pgp; ABCB1) are also associated with drug resistance in parasites, including helminths such as schistosomes. In addition to their association with drug resistance, however, ABC transporters also function in a wide variety of physiological processes in metazoans. In this review, we examine recent studies that help define the role of schistosome ABC transporters in regulating drug susceptibility, and in normal schistosome physiology, including reproduction and excretory activity. We postulate that schistosome ABC transporters could be useful targets for compounds that enhance the effectiveness of current therapeutics as well as for agents that act as antischistosomals on their own.
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Affiliation(s)
- Robert M Greenberg
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104, USA.
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Keiser J, Tritten L, Adelfio R, Vargas M. Effect of combinations of marketed human anthelmintic drugs against Trichuris muris in vitro and in vivo. Parasit Vectors 2012; 5:292. [PMID: 23231753 PMCID: PMC3533970 DOI: 10.1186/1756-3305-5-292] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 12/07/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Soil-transmitted helminth (STH) infections are responsible for a huge public health burden, however treatment options are limited. The discovery and development of novel efficacious drugs or drug combinations for the treatment of STH infections therefore has a high research priority. METHODS We studied drug combination effects using the main standard anthelmintics, albendazole, mebendazole, levamisole, pyrantel pamoate and ivermectin in the Trichuris muris model. Drug combinations were first tested in vitro and additive and synergistic combinations investigated further in vivo in female mice using ratios based on the ED50 of the respective drugs. RESULTS In vitro all 10 combinations of the standard anthelmintics tested against T. muris revealed synergistic behavior. We identified three drug combinations in vivo as strongly synergistic, namely mebendazole-ivermectin (Combination index (CI)=0.16), mebendazole-levamisole (CI=0.17) and albendazole-mebendazole (CI=0.23). For albendazole-ivermectin, moderate synergism was observed (CI=0.81) and for albendazole-levamisole a nearly additive effect was documented (CI=0.93) in vivo. Five combinations (albendazole-pyrantel pamoate, mebendazole-pyrantel pamoate, levamisole-pyrantel pamoate, levamisole-ivermectin and pyrantel pamoate-ivermectin) were antagonistic in vivo. CONCLUSION Our results strengthen the evidence that combination chemotherapy might play a role in the treatment of Trichuris infections. Albendazole-mebendazole should be studied in greater detail in preclinical studies.
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Affiliation(s)
- Jennifer Keiser
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland.
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Hui F, Scheib U, Hu Y, Sommer RJ, Aroian RV, Ghosh P. Structure and glycolipid binding properties of the nematicidal protein Cry5B. Biochemistry 2012; 51:9911-21. [PMID: 23150986 DOI: 10.1021/bi301386q] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Crystal (Cry) proteins are globally used in agriculture as proteinaceous insecticides. They have also been recently recognized to have great potential as anthelmintic agents in targeting parasitic roundworms (e.g., hookworms). The most extensively characterized of the anthelmintic Cry proteins is Cry5B. We report here the 2.3 Å resolution structure of the proteolytically activated form of Cry5B. This structure, which is the first for a nematicidal Cry protein, shows the familiar three-domain arrangement seen in insecticidal Cry proteins. However, domain II is unusual in that it more closely resembles a banana lectin than it does other Cry proteins. This result is consistent with the fact that the receptor for Cry5B consists of a set of invertebrate-specific glycans (attached to lipids) and also suggests that domain II is important for receptor binding. We found that not only galactose but also N-acetylgalactosamine (GalNAc) is an efficient competitor for binding between Cry5B and glycolipids. GalNAc is one of the core arthroseries tetrasaccharides of the Cry5B receptor and galactose an antennary sugar that emanates from this core. These and prior data suggest that the minimal binding determinant for Cry5B consists of a core GalNAc and two antennary galactoses. Lastly, the protoxin form of Cry5B was found to bind nematode glycolipids with a specificity equal to that of activated Cry5B, but with lower affinity. This suggests that the initial binding of Cry5B protoxin to glycolipids can be stabilized at the nematode cell surface by proteolysis. These results lay the groundwork for the design of effective Cry5B-based anthelmintics.
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Affiliation(s)
- Fan Hui
- Department of Chemistry and Biochemistry, 9500 Gilman Drive, University of California, San Diego, La Jolla, CA 92093-0375, USA
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Lubis IND, Pasaribu S, Lubis CP. Current status of the efficacy and effectiveness of albendazole and mebendazole for the treatment of Ascaris lumbricoides in North-Western Indonesia. ASIAN PAC J TROP MED 2012; 5:605-9. [PMID: 22840447 DOI: 10.1016/s1995-7645(12)60125-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 01/28/2012] [Accepted: 03/15/2012] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE To investigate the efficacy and effectiveness of albendazole and mebendazole in the treatment of Ascaris lumbricoides (A. lumbricoides) in the North-Western Indonesia. METHODS 229 primary school children who were positive for A. lumbricoides in their stool were recruited in the study. 123 children received single-dose of 400 mg albendazole and 106 children received single-dose 500 mg of mebendazole. After 1 week, their stools were examined for the cure rate (CR) and egg reduction rate (ERR). Egg culture was also performed and observation was made on week-1, -3, -4. RESULTS have shown a non-significant difference in CR 96.7%vs. 100% and ERR of 99.3%vs. 100.0% for albendazole and mebendazole groups respectively (P>0.05). In-vitro egg culture has shown trends of decrease in the percentage of the unfertilized eggs and in ≥ 2 cell eggs in both treatment groups (P<0.05). The embryonated eggs from the albendazole groups has shown an increase from 7.3% on week-1 to 13.8% on week-4, whilst the mebendazole group has shown a constant increase during the whole 4 weeks of culture from 7.5% to 28.3% (P<0.01). CONCLUSIONS No evidence of drug resistance is noted so far from the area of North-Western part of Indonesia. In addition, although both drugs showed incomplete ovicidal effects, single-dose albendazole is better than mebendazole in sterilizing A. lumbricoides eggs.
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Hu Y, Aroian RV. Bacterial pore-forming proteins as anthelmintics. INVERTEBRATE NEUROSCIENCE : IN 2012; 12:37-41. [PMID: 22562659 PMCID: PMC3889471 DOI: 10.1007/s10158-012-0135-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 04/18/2012] [Indexed: 12/21/2022]
Abstract
Crystal (Cry) proteins are made by the Gram-positive bacterium Bacillus thuringiensis (Bt). Cry proteins are pore-forming proteins and are the most widely used biological insecticides in the world. Our laboratory found some Cry proteins are highly effective against a broad range of nematodes (roundworms). Here, we discuss our results of Cry protein activity against intestinal roundworms. Both Cry5B and Cry21A have therapeutic activities against infections of the roundworm Heligmosomoides polygyrus bakeri in mice. Cry5B also shows highly therapeutic activity against Ancylostoma ceylanicum infection in hamsters. A. ceylanicum is a minor hookworm parasite of humans, and it is closely related to the more prevalent Ancylostoma duodenale. In addition, Cry proteins show excellent combinatorial therapeutic properties with nicotinic acetylcholine receptor (nAChR) agonists, one of the two classes of compounds approved by the World Health Organization for the treatment for intestinal roundworms in humans. Given their non-toxicity to humans and their broad spectrum of nematicidal action, Cry proteins show great potential as next-generation anthelmintics.
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Affiliation(s)
- Yan Hu
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive, Mail Code 0322, La Jolla, CA 92093-0322, USA
| | - Raffi V. Aroian
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive, Mail Code 0322, La Jolla, CA 92093-0322, USA
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Prichard RK, Basáñez MG, Boatin BA, McCarthy JS, García HH, Yang GJ, Sripa B, Lustigman S. A research agenda for helminth diseases of humans: intervention for control and elimination. PLoS Negl Trop Dis 2012; 6:e1549. [PMID: 22545163 PMCID: PMC3335868 DOI: 10.1371/journal.pntd.0001549] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recognising the burden helminth infections impose on human populations, and particularly the poor, major intervention programmes have been launched to control onchocerciasis, lymphatic filariasis, soil-transmitted helminthiases, schistosomiasis, and cysticercosis. The Disease Reference Group on Helminth Infections (DRG4), established in 2009 by the Special Programme for Research and Training in Tropical Diseases (TDR), was given the mandate to review helminthiases research and identify research priorities and gaps. A summary of current helminth control initiatives is presented and available tools are described. Most of these programmes are highly dependent on mass drug administration (MDA) of anthelmintic drugs (donated or available at low cost) and require annual or biannual treatment of large numbers of at-risk populations, over prolonged periods of time. The continuation of prolonged MDA with a limited number of anthelmintics greatly increases the probability that drug resistance will develop, which would raise serious problems for continuation of control and the achievement of elimination. Most initiatives have focussed on a single type of helminth infection, but recognition of co-endemicity and polyparasitism is leading to more integration of control. An understanding of the implications of control integration for implementation, treatment coverage, combination of pharmaceuticals, and monitoring is needed. To achieve the goals of morbidity reduction or elimination of infection, novel tools need to be developed, including more efficacious drugs, vaccines, and/or antivectorial agents, new diagnostics for infection and assessment of drug efficacy, and markers for possible anthelmintic resistance. In addition, there is a need for the development of new formulations of some existing anthelmintics (e.g., paediatric formulations). To achieve ultimate elimination of helminth parasites, treatments for the above mentioned helminthiases, and for taeniasis and food-borne trematodiases, will need to be integrated with monitoring, education, sanitation, access to health services, and where appropriate, vector control or reduction of the parasite reservoir in alternative hosts. Based on an analysis of current knowledge gaps and identification of priorities, a research and development agenda for intervention tools considered necessary for control and elimination of human helminthiases is presented, and the challenges to be confronted are discussed.
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