A perspective on genomic-guided anthelmintic discovery and repurposing using Haemonchus contortus
- Preston, Sarah, Jabbar, Abdul, Gasser, Robin
- Authors: Preston, Sarah , Jabbar, Abdul , Gasser, Robin
- Date: 2016
- Type: Text , Journal article
- Relation: Infection, Genetics and Evolution Vol. 40, no. (2016), p. 368-373
- Full Text: false
- Reviewed:
- Description: High-throughput molecular and computer technologies have become instrumental for systems biological explorations of parasites. Investigating the genomes and transcriptomes of different developmental stages of parasitic nematodes can provide insights into gene expression, regulation and function in the parasite, which is a significant step toward understanding their biology as well as host interactions and disease. This article covers aspects of a talk given at the MEEGID XII conference in Thailand in 2014. Here, we refer to recent studies of the genomes and transcriptomes of socioeconomically important parasitic nematodes of animals; provide an account of the barber's pole worm (Haemonchus contortus) and emerging drug resistance problems in this and related worms; we also propose a genomic-guided drug discovery and repurposing approach, involving the prediction of the druggable genome, prioritization of drug targets, screening of compound libraries against H. contortus and, briefly, a hit-to-lead optimization approach. We conclude by indicating prospects that molecular tool kits for nematodes provide to the scientific community for future comparative genomic, genetic, proteomic, metabolomic, evolutionary, biological, ecological and epidemiological investigations, and as a basis for biotechnological outcomes and translation. © 2015 Elsevier B.V.
- Jiao, Yaqing, Preston, Sarah, Hofmann, Andreas, Taki, Aya, Baell, Jonathan, Chang, Bill, Jabbar, Abdul, Gasser, Robin
- Authors: Jiao, Yaqing , Preston, Sarah , Hofmann, Andreas , Taki, Aya , Baell, Jonathan , Chang, Bill , Jabbar, Abdul , Gasser, Robin
- Date: 2020
- Type: Text , Book chapter
- Relation: Advances in Parasitology p. 1-45
- Full Text: false
- Reviewed:
- Description: Parasitic roundworms (nematodes) cause substantial morbidity and mortality in animals worldwide. Anthelmintic treatment is central to controlling these worms, but widespread resistance to most of the commercially available anthelmintics for veterinary and agricultural use is compromising control, such that there is an urgency to discover new and effective drugs. The purpose of this article is to review information on parasitic nematodes, the treatment and control of parasitic nematode infections and aspects of discovering new anthelmintics in the context of anthelmintic resistance problems, and then to discuss some progress that our group has made in identifying selected compounds with activity against nematodes. The focus of our recent work has been on discovering new chemical entities and known drugs with anthelmintic activities against Haemonchus contortus as well as other socioeconomically important parasitic nematodes for subsequent development. Using whole worm-based phenotypic assays, we have been screening compound collections obtained via product-development-partnerships and/or collaborators, and active compounds have been assessed for their potential as anthelmintic candidates. Following the screening of 15,333 chemicals from five distinct compound collections against H. contortus, we have discovered one new chemical entity (designated SN00797439), two human kinase inhibitors (SNS-032 and AG-1295), 14 tetrahydroquinoxaline analogues, one insecticide (tolfenpyrad) and two tolfenpyrad (pyrazole-5-carboxamide) derivatives (a-15 and a-17) with anthelmintic activity in vitro. Some of these 20 ‘hit’ compounds have selectivity against H. contortus in vitro when compared to particular human cell lines. In our opinion, some of these compounds could represent starting points for ‘lead’ development. Accordingly, the next research steps to be pursued include: (i) chemical optimisation of representative chemicals via structure-activity relationship (SAR) evaluations; (ii) assessment of the breadth of spectrum of anthelmintic activity on a range of other parasitic nematodes, such as strongyloids, ascaridoids, enoplids and filarioids; (iii) detailed investigations of the absorption, distribution, metabolism, excretion and toxicity (ADMET) of optimised chemicals with broad nematocidal or nematostatic activity; and (iv) establishment of the modes of action of lead candidates. © 2020 Elsevier Ltd
Advances in the discovery and development of anthelmintics by harnessing natural product scaffolds
- Herath, H. M. P. Dilrukshi, Taki, Aya, Sleebs, Brad, Hofmann, Andreas, Nguyen, Nghi, Preston, Sarah, Davis, Rohan, Jabbar, Abdul, Gasser, Robin
- Authors: Herath, H. M. P. Dilrukshi , Taki, Aya , Sleebs, Brad , Hofmann, Andreas , Nguyen, Nghi , Preston, Sarah , Davis, Rohan , Jabbar, Abdul , Gasser, Robin
- Date: 2021
- Type: Text , Book chapter
- Relation: Advances in Parasitology p. 203-251
- Full Text: false
- Reviewed:
- Description: Widespread resistance to currently-used anthelmintics represents a major obstacle to controlling parasitic nematodes of livestock animals. Given the reliance on anthelmintics in many control regimens, there is a need for the continued discovery and development of new nematocides. Enabling such a focus are: (i) the major chemical diversity of natural products; (ii) the availability of curated, drug-like extract-, fraction- and/or compound-libraries from natural sources; (iii) the utility and practicality of well-established whole-worm bioassays for Haemonchus contortus—an important parasitic nematodes of livestock—to screen natural product libraries; and (iv) the availability of advanced chromatographic (HPLC), spectroscopic (NMR) and spectrometric (MS) techniques for bioassay-guided fractionation and structural elucidation. This context provides a sound basis for the identification and characterisation of anthelmintic candidates from natural sources. This chapter provides a background on the importance and impact of helminth infections/diseases, parasite control and aspects of drug discovery, and reviews recent work focused on (i) screening well-defined compound libraries to establish the methods needed for large-scale screening of natural extract libraries; (ii) discovering plant and marine extracts with nematocidal or nematostatic activity, and purifying bioactive compounds and assessing their potential for further development; and (iii) synthesising analogues of selected purified natural compounds for the identification of possible ‘lead’ candidates. The chapter describes some lessons learned from this work and proposes future areas of focus for drug discovery. Collectively, the findings from this recent work show potential for selected natural product scaffolds as candidates for future development. Developing such candidates via future chemical optimisation, efficacy and safety evaluations, broad spectrum activity assessments, and target identification represents an exciting prospect and, if successful, could pave the way to subsequent pre-clinical and clinical evaluations. © 2021 Elsevier Ltd
Anthelmintic activity of selected ethno-medicinal plant extracts on parasitic stages of Haemonchus contortus
- Kumarasingha, Rasika, Preston, Sarah, Yeo, Tiong-Chia, Lim, Diana, Tu, Chu-Lee, Palombo, Enzo, Shaw, Jillian, Gasser, Robin, Boag, Peter
- Authors: Kumarasingha, Rasika , Preston, Sarah , Yeo, Tiong-Chia , Lim, Diana , Tu, Chu-Lee , Palombo, Enzo , Shaw, Jillian , Gasser, Robin , Boag, Peter
- Date: 2016
- Type: Text , Journal article
- Relation: Parasites and Vectors Vol. 9, no. 1 (2016), p. 1-7
- Full Text:
- Reviewed:
- Description: Background: Parasitic roundworms (nematodes) cause substantial morbidity and mortality in livestock animals globally, and considerable productivity losses to farmers. The control of these nematodes has relied largely on the use of a limited number of anthelmintics. However, resistance to many of these these anthelmintics is now widespread, and, therefore, there is a need to find new drugs to ensure sustained and effective treatment and control into the future. Methods: Recently, we developed a screening assay to test natural, plant extracts with known inhibitory effects against the free-living worm Caenorhabditis elegans. Using this assay, we assessed here the effects of the extracts on motility and development of parasitic larval stages of Haemonchus contortus, one of the most important nematodes of small ruminants worldwide. Results: The study showed that two of five extracts from Picria fel-terrae Lour. have a significant inhibitory effect (at concentrations of 3-5 mg/ml) on the motility and development of H. contortus larvae. Although the two extracts originated from the same plant, they displayed different levels of inhibition on motility and development, which might relate to the presence of various active constituents in these extracts, or the same constituents at different concentrations in distinct parts of the plant. Conclusions: These results suggest that extracts from P. fel-terrae Lour. have promising anthelmintic activity and that more broadly, plant extracts are a potential rich source of anthelmintics to combat helminthic diseases. © 2016 Kumarasingha et al.
- Authors: Kumarasingha, Rasika , Preston, Sarah , Yeo, Tiong-Chia , Lim, Diana , Tu, Chu-Lee , Palombo, Enzo , Shaw, Jillian , Gasser, Robin , Boag, Peter
- Date: 2016
- Type: Text , Journal article
- Relation: Parasites and Vectors Vol. 9, no. 1 (2016), p. 1-7
- Full Text:
- Reviewed:
- Description: Background: Parasitic roundworms (nematodes) cause substantial morbidity and mortality in livestock animals globally, and considerable productivity losses to farmers. The control of these nematodes has relied largely on the use of a limited number of anthelmintics. However, resistance to many of these these anthelmintics is now widespread, and, therefore, there is a need to find new drugs to ensure sustained and effective treatment and control into the future. Methods: Recently, we developed a screening assay to test natural, plant extracts with known inhibitory effects against the free-living worm Caenorhabditis elegans. Using this assay, we assessed here the effects of the extracts on motility and development of parasitic larval stages of Haemonchus contortus, one of the most important nematodes of small ruminants worldwide. Results: The study showed that two of five extracts from Picria fel-terrae Lour. have a significant inhibitory effect (at concentrations of 3-5 mg/ml) on the motility and development of H. contortus larvae. Although the two extracts originated from the same plant, they displayed different levels of inhibition on motility and development, which might relate to the presence of various active constituents in these extracts, or the same constituents at different concentrations in distinct parts of the plant. Conclusions: These results suggest that extracts from P. fel-terrae Lour. have promising anthelmintic activity and that more broadly, plant extracts are a potential rich source of anthelmintics to combat helminthic diseases. © 2016 Kumarasingha et al.
Arylpyrrole and fipronil analogues that inhibit the motility and/or development of Haemonchus contortus in vitro
- Herath, Dilrukshi, Song, Hongjian, Preston, Sarah, Jabbar, Abdul, Wang, Tao, McGee, Sean, Hofmann, Andreas, Garcia-Bustos, Jose, Chang, Bill, Koehler, Anson, Liu, Yuxiu, Ma, Qiaoqiao, Zhang, Penqxiang, Zhao, Qiqi, Wang, Qingmin, Gasser, Robin
- Authors: Herath, Dilrukshi , Song, Hongjian , Preston, Sarah , Jabbar, Abdul , Wang, Tao , McGee, Sean , Hofmann, Andreas , Garcia-Bustos, Jose , Chang, Bill , Koehler, Anson , Liu, Yuxiu , Ma, Qiaoqiao , Zhang, Penqxiang , Zhao, Qiqi , Wang, Qingmin , Gasser, Robin
- Date: 2018
- Type: Text , Journal article
- Relation: International Journal for Parasitology: Drugs and Drug Resistance Vol. 8, no. 3 (2018), p. 379-385
- Full Text:
- Reviewed:
- Description: Due to widespread drug resistance in parasitic nematodes, there is a need to develop new anthelmintics. Given the cost and time involved in developing a new drug, the repurposing of known chemicals can be a promising, alternative approach. In this context, we tested a library (n = 600) of natural product-inspired pesticide analogues against exsheathed third stage-larvae (xL3s) of Haemonchus contortus (barber's pole worm) using a whole-organism, phenotypic screening technique that measures the inhibition of motility and development in treated larvae. In the primary screen, we identified 32 active analogues derived from chemical scaffolds of arylpyrrole or fipronil. The seven most promising compounds, selected based on their anthelmintic activity and/or limited cytotoxicity, are arylpyrroles that reduced the motility of fourth-stage larvae (L4s) with significant potency (IC 50 values ranged from 0.04 ± 0.01
- Authors: Herath, Dilrukshi , Song, Hongjian , Preston, Sarah , Jabbar, Abdul , Wang, Tao , McGee, Sean , Hofmann, Andreas , Garcia-Bustos, Jose , Chang, Bill , Koehler, Anson , Liu, Yuxiu , Ma, Qiaoqiao , Zhang, Penqxiang , Zhao, Qiqi , Wang, Qingmin , Gasser, Robin
- Date: 2018
- Type: Text , Journal article
- Relation: International Journal for Parasitology: Drugs and Drug Resistance Vol. 8, no. 3 (2018), p. 379-385
- Full Text:
- Reviewed:
- Description: Due to widespread drug resistance in parasitic nematodes, there is a need to develop new anthelmintics. Given the cost and time involved in developing a new drug, the repurposing of known chemicals can be a promising, alternative approach. In this context, we tested a library (n = 600) of natural product-inspired pesticide analogues against exsheathed third stage-larvae (xL3s) of Haemonchus contortus (barber's pole worm) using a whole-organism, phenotypic screening technique that measures the inhibition of motility and development in treated larvae. In the primary screen, we identified 32 active analogues derived from chemical scaffolds of arylpyrrole or fipronil. The seven most promising compounds, selected based on their anthelmintic activity and/or limited cytotoxicity, are arylpyrroles that reduced the motility of fourth-stage larvae (L4s) with significant potency (IC 50 values ranged from 0.04 ± 0.01
Assessing the anthelmintic activity of pyrazole-5-carboxamide derivatives against Haemonchus contortus
- Jiao, Yaqing, Preston, Sarah, Song, Hongjian, Jabbar, Abdul, Liu, Yuxiu, Baell, Jonathan, Hofmann, Andreas, Hutchinson, Dana, Wang, Tao, Koehler, Anson, Fisher, Gillian, Andrews, Katherine, Laleu, Benoit, Palmer, Michael, Burrows, Jeremy, Wells, Timothy, Wang, Qingmin, Gasser, Robin
- Authors: Jiao, Yaqing , Preston, Sarah , Song, Hongjian , Jabbar, Abdul , Liu, Yuxiu , Baell, Jonathan , Hofmann, Andreas , Hutchinson, Dana , Wang, Tao , Koehler, Anson , Fisher, Gillian , Andrews, Katherine , Laleu, Benoit , Palmer, Michael , Burrows, Jeremy , Wells, Timothy , Wang, Qingmin , Gasser, Robin
- Date: 2017
- Type: Text , Journal article
- Relation: Parasites and Vectors Vol. 10, no. 1 (2017), p. 1-7
- Full Text:
- Reviewed:
- Description: Background: In this study, we tested five series of pyrazole-5-carboxamide compounds (n = 55) for activity against parasitic stages of the nematode Haemonchus contortus (barber’s pole worm), one of the most pathogenic parasites of ruminants. Methods: In an optimised, whole-organism screening assay, using exsheathed third-stage (xL3) and fourth-stage (L4) larvae, we measured the inhibition of larval motility and development of H. contortus. Results: Amongst the 55 compounds, we identified two compounds (designated a-15 and a-17) that reproducibly inhibit xL3 motility as well as L4 motility and development, with IC50 values ranging between ~3.4 and 55.6 μM. We studied the effect of these two ‘hit’ compounds on mitochondrial function by measuring oxygen consumption. This assessment showed that xL3s exposed to each of these compounds consumed significantly less oxygen and had less mitochondrial activity than untreated xL3s, which was consistent with specific inhibition of complex I of the respiratory electron transport chain in arthropods. Conclusions: The present findings provide a sound basis for future work, aimed at identifying the targets of compounds a-15 and a-17 and establishing the modes of action of these chemicals in H. contortus. © 2017 The Author(s).
- Authors: Jiao, Yaqing , Preston, Sarah , Song, Hongjian , Jabbar, Abdul , Liu, Yuxiu , Baell, Jonathan , Hofmann, Andreas , Hutchinson, Dana , Wang, Tao , Koehler, Anson , Fisher, Gillian , Andrews, Katherine , Laleu, Benoit , Palmer, Michael , Burrows, Jeremy , Wells, Timothy , Wang, Qingmin , Gasser, Robin
- Date: 2017
- Type: Text , Journal article
- Relation: Parasites and Vectors Vol. 10, no. 1 (2017), p. 1-7
- Full Text:
- Reviewed:
- Description: Background: In this study, we tested five series of pyrazole-5-carboxamide compounds (n = 55) for activity against parasitic stages of the nematode Haemonchus contortus (barber’s pole worm), one of the most pathogenic parasites of ruminants. Methods: In an optimised, whole-organism screening assay, using exsheathed third-stage (xL3) and fourth-stage (L4) larvae, we measured the inhibition of larval motility and development of H. contortus. Results: Amongst the 55 compounds, we identified two compounds (designated a-15 and a-17) that reproducibly inhibit xL3 motility as well as L4 motility and development, with IC50 values ranging between ~3.4 and 55.6 μM. We studied the effect of these two ‘hit’ compounds on mitochondrial function by measuring oxygen consumption. This assessment showed that xL3s exposed to each of these compounds consumed significantly less oxygen and had less mitochondrial activity than untreated xL3s, which was consistent with specific inhibition of complex I of the respiratory electron transport chain in arthropods. Conclusions: The present findings provide a sound basis for future work, aimed at identifying the targets of compounds a-15 and a-17 and establishing the modes of action of these chemicals in H. contortus. © 2017 The Author(s).
Deguelin exerts potent nematocidal activity via the mitochondrial respiratory chain
- Preston, Sarah, Korhonen, Pasi, Mouchiroud, Laurent, Cornaglia, Matteo, McGee, Sean, Young, Neil, Davis, Rohan, Crawford, Simon, Nowell, Cameron, Ansell, Brendan, Fisher, Gillian, Andrews, Katherine, Chang, Bill, Gijs, Martin, Sternberg, Paul, Auwerx, Johan, Baell, Jonathan, Hofmann, Andreas, Jabbar, Abdul, Gasser, Robin
- Authors: Preston, Sarah , Korhonen, Pasi , Mouchiroud, Laurent , Cornaglia, Matteo , McGee, Sean , Young, Neil , Davis, Rohan , Crawford, Simon , Nowell, Cameron , Ansell, Brendan , Fisher, Gillian , Andrews, Katherine , Chang, Bill , Gijs, Martin , Sternberg, Paul , Auwerx, Johan , Baell, Jonathan , Hofmann, Andreas , Jabbar, Abdul , Gasser, Robin
- Date: 2017
- Type: Text , Journal article
- Relation: FASEB Journal Vol. 31, no. 10 (2017), p. 4515-4532
- Full Text: false
- Reviewed:
- Description: As a result of limited classes of anthelmintics and an over-reliance on chemical control, there is a great need to discover new compounds to combat drug resistance in parasitic nematodes. Here, we show that deguelin, a plant-derived rotenoid, selectively and potently inhibits the motility and development of nematodes, which supports its potential as a lead candidate for drug development. Furthermore, we demonstrate that deguelin treatment significantly increases gene transcription that is associated with energy metabolism, particularly oxidative phosphorylation and mitoribosomal protein production before inhibiting motility. Mitochondrial tracking confirmed enhanced oxidative phosphorylation. In accordance, real-time measurements of oxidative phosphorylation in response to deguelin treatment demonstrated an immediate decrease in oxygen consumption in both parasitic (Haemonchus contortus) and free-living (Caenorhabditis elegans) nematodes. Consequently, we hypothesize that deguelin is exerting its toxic effect on nematodes as a modulator of oxidative phosphorylation. This study highlights the dynamic biologic response of multicellular organisms to deguelin perturbation. © FASEB.
DRfit : A Java tool for the analysis of discrete data from multi-well plate assays
- Hofmann, Andreas, Preston, Sarah, Cross, Megan, Herath, Dilrukshi, Simon, Anne, Gasser, Robin
- Authors: Hofmann, Andreas , Preston, Sarah , Cross, Megan , Herath, Dilrukshi , Simon, Anne , Gasser, Robin
- Date: 2019
- Type: Text , Journal article
- Relation: BMC Bioinformatics Vol. 20, no. (2019), p. 1-6
- Full Text:
- Reviewed:
- Description: Background: Analyses of replicates in sets of discrete data, typically acquired in multi-well plate formats, is a recurring task in many contemporary areas in the Life Sciences. The availability of accessible cross-platform data analysis tools for such fundamental tasks in varied projects and environments is an important prerequisite to ensuring a reliable and timely turnaround as well as to provide practical analytical tools for student training. Results: We have developed an easy-to-use, interactive software tool for the analysis of multiple data sets comprising replicates of discrete bivariate data points. For each dataset, the software identifies the replicate data points from a defined matrix layout and calculates their means and standard errors. The averaged values are then automatically fitted using either a linear or a logistic dose response function. Conclusions: DRfit is a practical and convenient tool for the analysis of one or multiple sets of discrete data points acquired as replicates from multi-well plate assays. The design of the graphical user interface and the built-in analysis features make it a flexible and useful tool for a wide range of different assays.
- Authors: Hofmann, Andreas , Preston, Sarah , Cross, Megan , Herath, Dilrukshi , Simon, Anne , Gasser, Robin
- Date: 2019
- Type: Text , Journal article
- Relation: BMC Bioinformatics Vol. 20, no. (2019), p. 1-6
- Full Text:
- Reviewed:
- Description: Background: Analyses of replicates in sets of discrete data, typically acquired in multi-well plate formats, is a recurring task in many contemporary areas in the Life Sciences. The availability of accessible cross-platform data analysis tools for such fundamental tasks in varied projects and environments is an important prerequisite to ensuring a reliable and timely turnaround as well as to provide practical analytical tools for student training. Results: We have developed an easy-to-use, interactive software tool for the analysis of multiple data sets comprising replicates of discrete bivariate data points. For each dataset, the software identifies the replicate data points from a defined matrix layout and calculates their means and standard errors. The averaged values are then automatically fitted using either a linear or a logistic dose response function. Conclusions: DRfit is a practical and convenient tool for the analysis of one or multiple sets of discrete data points acquired as replicates from multi-well plate assays. The design of the graphical user interface and the built-in analysis features make it a flexible and useful tool for a wide range of different assays.
Hc-daf-2 encodes an insulin-like receptor kinase in the barber's pole worm, Haemonchus contortus, and restores partial dauer regulation
- Li, Facai, Lok, James, Gasser, Robin, Korhonen, Pasi, Sandeman, Mark, Shi, Deshi, Zhou, Rui, Li, Xiangrui, Zhou, Yanqin, Zhao, Junlong, Hu, Min
- Authors: Li, Facai , Lok, James , Gasser, Robin , Korhonen, Pasi , Sandeman, Mark , Shi, Deshi , Zhou, Rui , Li, Xiangrui , Zhou, Yanqin , Zhao, Junlong , Hu, Min
- Date: 2014
- Type: Text , Journal article
- Relation: International Journal for Parasitology Vol. 44, no. 7 (2014), p. 485-496
- Full Text:
- Reviewed:
- Description: Infective L3s (iL3s) of parasitic nematodes share common behavioural, morphological and developmental characteristics with the developmentally arrested (dauer) larvae of the free-living nematode Caenorhabditis elegans. It is proposed that similar molecular mechanisms regulate entry into or exit from the dauer stage in C. elegans, and the transition from free-living to parasitic forms of parasitic nematodes. In C. elegans, one of the key factors regulating the dauer transition is the insulin-like receptor (designated Ce-DAF-2) encoded by the gene Ce-daf-2. However, nothing is known about DAF-2 homologues in most parasitic nematodes. Here, using a PCR-based approach, we identified and characterised a gene (Hc-daf-2) and its inferred product (Hc-DAF-2) in Haemonchus contortus (a socioeconomically important parasitic nematode of ruminants). The sequence of Hc-DAF-2 displays significant sequence homology to insulin receptors (IR) in both vertebrates and invertebrates, and contains conserved structural domains. A sequence encoding an important proteolytic motif (RKRR) identified in the predicted peptide sequence of Hc-DAF-2 is consistent with that of the human IR, suggesting that it is involved in the formation of the IR complex. The Hc-daf-2 gene was transcribed in all life stages of H. contortus, with a significant up-regulation in the iL3 compared with other stages. To compare patterns of expression between Hc-daf-2 and Ce-daf-2, reporter constructs fusing the Ce-daf-2 or Hc-daf-2 promoter to sequence encoding GFP were microinjected into the N2 strain of C. elegans, and transgenic lines were established and examined. Both genes showed similar patterns of expression in amphidial (head) neurons, which relate to sensation and signal transduction. Further study by heterologous genetic complementation in a daf-2-deficient strain of C. elegans (CB1370) showed partial rescue of function by Hc-daf-2. Taken together, these findings provide a first insight into the roles of Hc-daf-2/. Hc-DAF-2 in the biology and development of H. contortus, particularly in the transition to parasitism. © 2014 Australian Society for Parasitology Inc.
- Authors: Li, Facai , Lok, James , Gasser, Robin , Korhonen, Pasi , Sandeman, Mark , Shi, Deshi , Zhou, Rui , Li, Xiangrui , Zhou, Yanqin , Zhao, Junlong , Hu, Min
- Date: 2014
- Type: Text , Journal article
- Relation: International Journal for Parasitology Vol. 44, no. 7 (2014), p. 485-496
- Full Text:
- Reviewed:
- Description: Infective L3s (iL3s) of parasitic nematodes share common behavioural, morphological and developmental characteristics with the developmentally arrested (dauer) larvae of the free-living nematode Caenorhabditis elegans. It is proposed that similar molecular mechanisms regulate entry into or exit from the dauer stage in C. elegans, and the transition from free-living to parasitic forms of parasitic nematodes. In C. elegans, one of the key factors regulating the dauer transition is the insulin-like receptor (designated Ce-DAF-2) encoded by the gene Ce-daf-2. However, nothing is known about DAF-2 homologues in most parasitic nematodes. Here, using a PCR-based approach, we identified and characterised a gene (Hc-daf-2) and its inferred product (Hc-DAF-2) in Haemonchus contortus (a socioeconomically important parasitic nematode of ruminants). The sequence of Hc-DAF-2 displays significant sequence homology to insulin receptors (IR) in both vertebrates and invertebrates, and contains conserved structural domains. A sequence encoding an important proteolytic motif (RKRR) identified in the predicted peptide sequence of Hc-DAF-2 is consistent with that of the human IR, suggesting that it is involved in the formation of the IR complex. The Hc-daf-2 gene was transcribed in all life stages of H. contortus, with a significant up-regulation in the iL3 compared with other stages. To compare patterns of expression between Hc-daf-2 and Ce-daf-2, reporter constructs fusing the Ce-daf-2 or Hc-daf-2 promoter to sequence encoding GFP were microinjected into the N2 strain of C. elegans, and transgenic lines were established and examined. Both genes showed similar patterns of expression in amphidial (head) neurons, which relate to sensation and signal transduction. Further study by heterologous genetic complementation in a daf-2-deficient strain of C. elegans (CB1370) showed partial rescue of function by Hc-daf-2. Taken together, these findings provide a first insight into the roles of Hc-daf-2/. Hc-DAF-2 in the biology and development of H. contortus, particularly in the transition to parasitism. © 2014 Australian Society for Parasitology Inc.
Identification of fromiamycalin and halaminol A from Australian marine sponge extracts with anthelmintic activity against haemonchus contortus
- Herath, Dilrukshi, Preston, Sarah, Jabbar, Abdul, Garcia-Bustos, Jose, Taki, Aya, Addison, Russell, Hayes, Sasha, Beattie, Karren, McGee, Sean, Martin, Sheree, Ekin, Merrick, Hooper, John, Chang, Bill, Hofmann, Andreas, Davis, Rohan, Gasser, Robin
- Authors: Herath, Dilrukshi , Preston, Sarah , Jabbar, Abdul , Garcia-Bustos, Jose , Taki, Aya , Addison, Russell , Hayes, Sasha , Beattie, Karren , McGee, Sean , Martin, Sheree , Ekin, Merrick , Hooper, John , Chang, Bill , Hofmann, Andreas , Davis, Rohan , Gasser, Robin
- Date: 2019
- Type: Text , Journal article
- Relation: Marine Drugs Vol. 17, no. 11 (Nov 2019), p. 14
- Full Text:
- Reviewed:
- Description: There is an urgent need to discover and develop new anthelmintics for the treatment of parasitic nematodes of veterinary importance to circumvent challenges linked to drug resistant parasites. Being one of the most diverse natural ecosystems, the marine environment represents a rich resource of novel chemical entities. This study investigated 2000 extracts from marine invertebrates, collected from Australian waters, for anthelmintic activity. Using a well-established in vitro bioassay, these extracts were screened for nematocidal activity against Haemonchus contortus - a socioeconomically important parasitic nematode of livestock animals. Extracts (designated Mu-1, Ha-1 and Ha-2) from two marine sponges (Monanchora unguiculata and Haliclona sp.) each significantly affected larvae of H. contortus. Individual extracts displayed a dose-dependent inhibition of both the motility of exsheathed third-stage larvae (xL3s) and the development of xL3s to fourth-stage larvae (L4s). Active fractions in each of the three extracts were identified using bioassay-guided fractionation. From the active fractions from Monanchora unguiculata, a known pentacyclic guanidine alkaloid, fromiamycalin (1), was purified. This alkaloid was shown to be a moderately potent inhibitor of L4 development (half-maximum inhibitory concentration (IC50) = 26.6 +/- 0.74 mu M) and L4 motility (IC50 = 39.4 +/- 4.83 mu M), although it had a relatively low potency at inhibiting of xL3 motility (IC50 >= 100 mu M). Investigation of the active fractions from the two Haliclona collections led to identification of a mixture of amino alcohol lipids, and, subsequently, a known natural product halaminol A (5). Anthelmintic profiling showed that 5 had limited potency at inhibiting larval development and motility. These data indicate that fromiamycalin, other related pentacyclic guanidine alkaloids and/or halaminols could have potential as anthelmintics following future medicinal chemistry efforts.
- Authors: Herath, Dilrukshi , Preston, Sarah , Jabbar, Abdul , Garcia-Bustos, Jose , Taki, Aya , Addison, Russell , Hayes, Sasha , Beattie, Karren , McGee, Sean , Martin, Sheree , Ekin, Merrick , Hooper, John , Chang, Bill , Hofmann, Andreas , Davis, Rohan , Gasser, Robin
- Date: 2019
- Type: Text , Journal article
- Relation: Marine Drugs Vol. 17, no. 11 (Nov 2019), p. 14
- Full Text:
- Reviewed:
- Description: There is an urgent need to discover and develop new anthelmintics for the treatment of parasitic nematodes of veterinary importance to circumvent challenges linked to drug resistant parasites. Being one of the most diverse natural ecosystems, the marine environment represents a rich resource of novel chemical entities. This study investigated 2000 extracts from marine invertebrates, collected from Australian waters, for anthelmintic activity. Using a well-established in vitro bioassay, these extracts were screened for nematocidal activity against Haemonchus contortus - a socioeconomically important parasitic nematode of livestock animals. Extracts (designated Mu-1, Ha-1 and Ha-2) from two marine sponges (Monanchora unguiculata and Haliclona sp.) each significantly affected larvae of H. contortus. Individual extracts displayed a dose-dependent inhibition of both the motility of exsheathed third-stage larvae (xL3s) and the development of xL3s to fourth-stage larvae (L4s). Active fractions in each of the three extracts were identified using bioassay-guided fractionation. From the active fractions from Monanchora unguiculata, a known pentacyclic guanidine alkaloid, fromiamycalin (1), was purified. This alkaloid was shown to be a moderately potent inhibitor of L4 development (half-maximum inhibitory concentration (IC50) = 26.6 +/- 0.74 mu M) and L4 motility (IC50 = 39.4 +/- 4.83 mu M), although it had a relatively low potency at inhibiting of xL3 motility (IC50 >= 100 mu M). Investigation of the active fractions from the two Haliclona collections led to identification of a mixture of amino alcohol lipids, and, subsequently, a known natural product halaminol A (5). Anthelmintic profiling showed that 5 had limited potency at inhibiting larval development and motility. These data indicate that fromiamycalin, other related pentacyclic guanidine alkaloids and/or halaminols could have potential as anthelmintics following future medicinal chemistry efforts.
Low cost whole-organism screening of compounds for anthelmintic activity
- Preston, Sarah, Jabbar, Abdul, Nowell, Cameron, Joachim, Anja, Ruttkowski, Barbel, Baell, Jonathan, Cardno, Tony, Korhonen, Pasi, Piedrafita, David, Ansell, Brendan, Jex, Aaron, Hofmann, Andreas, Gasser, Robin
- Authors: Preston, Sarah , Jabbar, Abdul , Nowell, Cameron , Joachim, Anja , Ruttkowski, Barbel , Baell, Jonathan , Cardno, Tony , Korhonen, Pasi , Piedrafita, David , Ansell, Brendan , Jex, Aaron , Hofmann, Andreas , Gasser, Robin
- Date: 2015
- Type: Text , Journal article
- Relation: International Journal for Parasitology Vol. 45, no. 5 (2015), p. 333-343
- Full Text: false
- Reviewed:
- Description: Due to major problems with drug resistance in parasitic nematodes of animals, there is a substantial need and excellent opportunities to develop new anthelmintics via genomic-guided and/or repurposing approaches. In the present study, we established a practical and cost-effective whole-organism assay for the in vitro-screening of compounds for activity against parasitic stages of the nematode Haemonchus contortus (barber's pole worm). The assay is based on the use of exsheathed L3 (xL3) and L4 stages of H. contortus of small ruminants (sheep and goats). Using this assay, we screened a panel of 522 well-curated kinase inhibitors (GlaxoSmithKline, USA; code: PKIS2) for activity against H. contortus by measuring the inhibition of larval motility using an automated image analysis system. We identified two chemicals within the compound classes biphenyl amides and pyrazolo[1,5-α]pyridines, which reproducibly inhibit both xL3 and L4 motility and development, with IC50s of 14-47μM. Given that these inhibitors were designed as anti-inflammatory drugs for use in humans and fit the Lipinski rule-of-five (including bioavailability), they show promise for hit-to-lead optimisation and repurposing for use against parasitic nematodes. The screening assay established here has significant advantages over conventional methods, particularly in terms of ease of use, throughput, time and cost. Although not yet fully automated, the current assay is readily suited to the screening of hundreds to thousands of compounds for subsequent hit-to-lead optimisation. The current assay is highly adaptable to many parasites of socioeconomic importance, including those causing neglected tropical diseases. This aspect is of major relevance, given the urgent need to deliver the goals of the London Declaration (
Metabolic profiling and in vitro assessment of anthelmintic fractions of Picria fel-terrae Lour
- Kumarasingha, Rasika, Karpe, Avinash, Preston, Sarah, Yeo, Tiong-Chia, Lim, Diana, Tu, Chu-Lee, Luu, Jennii, Simpson, Kaylene, Shaw, Jillian, Gasser, Robin, Beale, David, Morrison, Paul, Palombo, Enzo, Boag, Peter
- Authors: Kumarasingha, Rasika , Karpe, Avinash , Preston, Sarah , Yeo, Tiong-Chia , Lim, Diana , Tu, Chu-Lee , Luu, Jennii , Simpson, Kaylene , Shaw, Jillian , Gasser, Robin , Beale, David , Morrison, Paul , Palombo, Enzo , Boag, Peter
- Date: 2016
- Type: Text , Journal article
- Relation: International Journal for Parasitology: Drugs and Drug Resistance Vol. 6, no. 3 (2016), p. 171-178
- Full Text:
- Reviewed:
- Description: Anthelmintic resistance is widespread in gastrointestinal nematode populations, such that there is a consistent need to search for new anthelmintics. However, the cost of screening for new compounds is high and has a very low success rate. Using the knowledge of traditional healers from Borneo Rainforests (Sarawak, Malaysia), we have previously shown that some traditional medicinal plants are a rich source of potential new anthelmintic drug candidates. In this study, Picria fel-terrae Lour. plant extract, which has previously shown promising anthelmintic activities, was fractionated via the use of a solid phase extraction cartridge and each isolated fraction was then tested on free-living nematode Caenorhabditis elegans and the parasitic nematode Haemonchus contortus. We found that a single fraction was enriched for nematocidal activity, killing ≥90% of C. elegans adults and inhibiting the motility of exsheathed L3 of H. contortus, while having minimal cytotoxic activity in mammalian cell culture. Metabolic profiling and chemometric analysis of the effective fraction indicated medium chained fatty acids and phenolic acids were highly represented. Image 1 •Chemical fractionation of Picria fel-terrae Lour. plant extract.•Anthelmintic activity against Caenorhabditis elegans and Haemonchus contortus.•Metabolic profiling and chemometric analysis of active fraction.•Active fraction has minimal mammalian cytotoxicity.
- Authors: Kumarasingha, Rasika , Karpe, Avinash , Preston, Sarah , Yeo, Tiong-Chia , Lim, Diana , Tu, Chu-Lee , Luu, Jennii , Simpson, Kaylene , Shaw, Jillian , Gasser, Robin , Beale, David , Morrison, Paul , Palombo, Enzo , Boag, Peter
- Date: 2016
- Type: Text , Journal article
- Relation: International Journal for Parasitology: Drugs and Drug Resistance Vol. 6, no. 3 (2016), p. 171-178
- Full Text:
- Reviewed:
- Description: Anthelmintic resistance is widespread in gastrointestinal nematode populations, such that there is a consistent need to search for new anthelmintics. However, the cost of screening for new compounds is high and has a very low success rate. Using the knowledge of traditional healers from Borneo Rainforests (Sarawak, Malaysia), we have previously shown that some traditional medicinal plants are a rich source of potential new anthelmintic drug candidates. In this study, Picria fel-terrae Lour. plant extract, which has previously shown promising anthelmintic activities, was fractionated via the use of a solid phase extraction cartridge and each isolated fraction was then tested on free-living nematode Caenorhabditis elegans and the parasitic nematode Haemonchus contortus. We found that a single fraction was enriched for nematocidal activity, killing ≥90% of C. elegans adults and inhibiting the motility of exsheathed L3 of H. contortus, while having minimal cytotoxic activity in mammalian cell culture. Metabolic profiling and chemometric analysis of the effective fraction indicated medium chained fatty acids and phenolic acids were highly represented. Image 1 •Chemical fractionation of Picria fel-terrae Lour. plant extract.•Anthelmintic activity against Caenorhabditis elegans and Haemonchus contortus.•Metabolic profiling and chemometric analysis of active fraction.•Active fraction has minimal mammalian cytotoxicity.
Novel 1-Methyl-1H-pyrazole-5-carboxamide derivatives with potent anthelmintic activity
- Le, Thuy, Kundu, Abhijit, Ghoshal, Atanu, Nguyen, Nghi, Preston, Sarah, Jiao, Yaqing, Ruan, Banfeng, Xue, Lian, Huang, Fei, Keiser, Jennifer, Hofmann, Andreas, Chang, Bill, Garcia-Bustos, Jose, Wells, Timothy, Palmer, Michael, Jabbar, Abdul, Gasser, Robin, Baell, Jonathan
- Authors: Le, Thuy , Kundu, Abhijit , Ghoshal, Atanu , Nguyen, Nghi , Preston, Sarah , Jiao, Yaqing , Ruan, Banfeng , Xue, Lian , Huang, Fei , Keiser, Jennifer , Hofmann, Andreas , Chang, Bill , Garcia-Bustos, Jose , Wells, Timothy , Palmer, Michael , Jabbar, Abdul , Gasser, Robin , Baell, Jonathan
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Medicinal Chemistry Vol. 62, no. 7 (2019), p. 3367-3380
- Full Text: false
- Reviewed:
- Description: A phenotypic screen of two different libraries of small molecules against the motility and development of the parasitic nematode Haemonchus contortus led to the identification of two 1-methyl-1H-pyrazole-5-carboxamide derivatives. Medicinal chemistry optimization targeted modifications of the left-hand side, middle section, and right-hand side of the hybrid structure of these two hits to elucidate the structure-activity relationship (SAR). Initial SAR around these hits allowed for the iterative and directed assembly of a focused set of 30 analogues of their hybrid structure. Compounds 10, 17, 20, and 22 were identified as the most potent compounds, inhibiting the development of the fourth larval (L4) stage of H. contortus at sub-nanomolar potencies while displaying strong selectivity toward the parasite when tested in vitro against the human MCF10A cell line. In addition, compounds 9 and 27 showed promising activity against a panel of other parasitic nematodes, including hookworms and whipworms.
- Le, Thuy, Kunda, Abhijit, Ghoshal, Atanu, Preston, Sarah, Jiao, Yaqing, Ruan, Banfeng, Xue, Lian, Huang, Fei, Keiser, Jennifer, Hofmann, Andreas, Chang, Bill, Garcia-Bustos, Jose, Jabbar, Abdul, Wells, Timothy, Palmer, Michael, Gasser, Robin, Baell, Jonathan
- Authors: Le, Thuy , Kunda, Abhijit , Ghoshal, Atanu , Preston, Sarah , Jiao, Yaqing , Ruan, Banfeng , Xue, Lian , Huang, Fei , Keiser, Jennifer , Hofmann, Andreas , Chang, Bill , Garcia-Bustos, Jose , Jabbar, Abdul , Wells, Timothy , Palmer, Michael , Gasser, Robin , Baell, Jonathan
- Date: 2018
- Type: Text , Journal article
- Relation: Journal of Medicinal Chemistry Vol. 61, no. 23 (2018), p. 10875-10894
- Full Text: false
- Reviewed:
- Description: A phenotypic screen of a diverse library of small molecules for inhibition of the development of larvae of the parasitic nematode Haemonchus contortus led to the identification of a 1-methyl-1H-pyrazole-5-carboxamide derivative with an IC
Phenotypic screening of the 'Kurz-box' of chemicals identifies two compounds (BLK127 and HBK4) with anthelmintic activity in vitro against parasitic larval stages of Haemonchus contortus
- Nguyen, Linh, Kurz, Thomas, Preston, Sarah, Brueckmann, Hjoerdis, Lungerich, Beate, Herath, Dilrukshi, Koehler, Anson, Wang, Tao, Skalova, Lenka, Jabbar, Abdul, Gasser, Robin
- Authors: Nguyen, Linh , Kurz, Thomas , Preston, Sarah , Brueckmann, Hjoerdis , Lungerich, Beate , Herath, Dilrukshi , Koehler, Anson , Wang, Tao , Skalova, Lenka , Jabbar, Abdul , Gasser, Robin
- Date: 2019
- Type: Text , Journal article
- Relation: Parasites & Vectors Vol. 12, no. (2019), p. 1-9
- Full Text:
- Reviewed:
- Description: BackgroundDue to anthelmintic resistance problems, there is a need to discover and develop new drugs for the treatment and control of economically important and pathogenic nematodes of livestock animals. With this focus in mind, we screened 236 compounds from a library (called the Kurz-box') representing chemically diverse classes such as heterocyclic compounds (e.g. thiazoles, pyrroles, quinolines, pyrimidines, benzo[1,4]diazepines), hydoxamic acid-based metalloenzyme inhibitors, peptidomimetics (bis- and tris-pyrimidoneamides, alkoxyamides) and various intermediates on Haemonchus contortus, one of the most important parasitic nematodes of ruminants.MethodsIn the present study, we tested these compounds, and measured the inhibition of larval motility and development of exsheathed third-stage (xL3) and fourth-stage (L4) larvae of H. contortus using an optimised, whole-organism phenotypic screening assay.ResultsOf the 236 compounds, we identified two active compounds (called BLK127 and HBK4) that induced marked phenotypic changes in the worm in vitro. Compound BLK127 induced an eviscerated' phenotype in the xL3 stage and also inhibited L4 development. Compound HBK4 exerted a curved' phenotype in both xL3s and L4s.ConclusionsThe findings from this study provide a basis for future work on the chemical optimisation of these compounds, on assessing the activity of optimised compounds on adult stages of H. contortus both in vitro and in vivo (in the host animal) and against other parasitic worms of veterinary and medical importance.
- Authors: Nguyen, Linh , Kurz, Thomas , Preston, Sarah , Brueckmann, Hjoerdis , Lungerich, Beate , Herath, Dilrukshi , Koehler, Anson , Wang, Tao , Skalova, Lenka , Jabbar, Abdul , Gasser, Robin
- Date: 2019
- Type: Text , Journal article
- Relation: Parasites & Vectors Vol. 12, no. (2019), p. 1-9
- Full Text:
- Reviewed:
- Description: BackgroundDue to anthelmintic resistance problems, there is a need to discover and develop new drugs for the treatment and control of economically important and pathogenic nematodes of livestock animals. With this focus in mind, we screened 236 compounds from a library (called the Kurz-box') representing chemically diverse classes such as heterocyclic compounds (e.g. thiazoles, pyrroles, quinolines, pyrimidines, benzo[1,4]diazepines), hydoxamic acid-based metalloenzyme inhibitors, peptidomimetics (bis- and tris-pyrimidoneamides, alkoxyamides) and various intermediates on Haemonchus contortus, one of the most important parasitic nematodes of ruminants.MethodsIn the present study, we tested these compounds, and measured the inhibition of larval motility and development of exsheathed third-stage (xL3) and fourth-stage (L4) larvae of H. contortus using an optimised, whole-organism phenotypic screening assay.ResultsOf the 236 compounds, we identified two active compounds (called BLK127 and HBK4) that induced marked phenotypic changes in the worm in vitro. Compound BLK127 induced an eviscerated' phenotype in the xL3 stage and also inhibited L4 development. Compound HBK4 exerted a curved' phenotype in both xL3s and L4s.ConclusionsThe findings from this study provide a basis for future work on the chemical optimisation of these compounds, on assessing the activity of optimised compounds on adult stages of H. contortus both in vitro and in vivo (in the host animal) and against other parasitic worms of veterinary and medical importance.
Proteomic identification of galectin-11 and 14 ligands from Haemonchus contortus
- Sakthivel, Dhanasekaran, Swan, Jaclyn, Preston, Sarah, Shakif-Azam, MD, Faou, Pierre, Jiao, Yaqing, Downs, Rachael, Rajapaksha, Harinda, Gasser, Robin, Piedrafita, David, Beddoe, Travis
- Authors: Sakthivel, Dhanasekaran , Swan, Jaclyn , Preston, Sarah , Shakif-Azam, MD , Faou, Pierre , Jiao, Yaqing , Downs, Rachael , Rajapaksha, Harinda , Gasser, Robin , Piedrafita, David , Beddoe, Travis
- Date: 2018
- Type: Text , Journal article
- Relation: Peerj Vol. 6, no. 3 (2018), p. 1-19
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- Description: Haemonchus contortus is the most pathogenic nematode of small ruminants. Infection in sheep and goats results in anaemia that decreases animal productivity and can ultimately cause death. The involvement of ruminant-specific galectin-11 (LGALS-11) and galectin-14 (LGALS-14) has been postulated to play important roles in protective immune responses against parasitic infection; however, their ligands are unknown. In the current study, LGALS-11 and LGALS-14 ligands in H. contortus were identified from larval (L4) and adult parasitic stages extracts using immobilised LGALS-11 and LGALS-14 affinity column chromatography and mass spectrometry. Both LGALS-11 and LGALS-14 bound more putative protein targets in the adult stage of H. contortus (43 proteins) when compared to the larval stage (two proteins). Of the 43 proteins identified in the adult stage, 34 and 35 proteins were bound by LGALS-11 and LGALS-14, respectively, with 26 proteins binding to both galectins. Interestingly, hematophagous stage-specific sperm-coating protein and zinc metalloprotease (M13), which are known vaccine candidates, were identified as putative ligands of both LGALS-11 and LGALS- 14. The identification of glycoproteins of H. contortus by LGALS-11 and LGALS-14 provide new insights into host-parasite interactions and the potential for developing new interventions.
- Authors: Sakthivel, Dhanasekaran , Swan, Jaclyn , Preston, Sarah , Shakif-Azam, MD , Faou, Pierre , Jiao, Yaqing , Downs, Rachael , Rajapaksha, Harinda , Gasser, Robin , Piedrafita, David , Beddoe, Travis
- Date: 2018
- Type: Text , Journal article
- Relation: Peerj Vol. 6, no. 3 (2018), p. 1-19
- Full Text:
- Reviewed:
- Description: Haemonchus contortus is the most pathogenic nematode of small ruminants. Infection in sheep and goats results in anaemia that decreases animal productivity and can ultimately cause death. The involvement of ruminant-specific galectin-11 (LGALS-11) and galectin-14 (LGALS-14) has been postulated to play important roles in protective immune responses against parasitic infection; however, their ligands are unknown. In the current study, LGALS-11 and LGALS-14 ligands in H. contortus were identified from larval (L4) and adult parasitic stages extracts using immobilised LGALS-11 and LGALS-14 affinity column chromatography and mass spectrometry. Both LGALS-11 and LGALS-14 bound more putative protein targets in the adult stage of H. contortus (43 proteins) when compared to the larval stage (two proteins). Of the 43 proteins identified in the adult stage, 34 and 35 proteins were bound by LGALS-11 and LGALS-14, respectively, with 26 proteins binding to both galectins. Interestingly, hematophagous stage-specific sperm-coating protein and zinc metalloprotease (M13), which are known vaccine candidates, were identified as putative ligands of both LGALS-11 and LGALS- 14. The identification of glycoproteins of H. contortus by LGALS-11 and LGALS-14 provide new insights into host-parasite interactions and the potential for developing new interventions.
- Herath, Dilrukshi, Preston, Sarah, Hofmann, Andreas, Davis, Rohan, Koehler, Anson, Chang, Bill, Jabbar, Abdul, Gasser, Robin
- Authors: Herath, Dilrukshi , Preston, Sarah , Hofmann, Andreas , Davis, Rohan , Koehler, Anson , Chang, Bill , Jabbar, Abdul , Gasser, Robin
- Date: 2017
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 244, no. (2017), p. 172-175
- Full Text: false
- Reviewed:
- Description: The control of parasitic roundworms (nematodes) is heavily reliant on the use of a limited number of anthelmintic drugs. However, drug resistance is now very widespread and no vaccines are available, such that the discovery of new chemical entities is crucial. Within this context, we screened a library of pure natural products (n = 400) against exsheathed third-stage (xL3) larvae of the parasitic nematode Haemonchus contortus using a whole-organism screening method. We identified two plant-derived rotenoids, deguelin and rotenone, with inhibitory activity on xL3 motility. Rotenone was not investigated further, because of its toxicity to some vertebrates. The dose response and cytotoxicity studies showed potent and selective inhibitory activity of deguelin on motility of xL3 larvae of H. contortus. Detailed future work needs to be conducted to explore the mode of action of this compound on H. contortus and related nematodes, and to assess its potential as an anthelmintic candidate. © 2017 Elsevier B.V.
Screening of the ‘Open Scaffolds’ collection from Compounds Australia identifies a new chemical entity with anthelmintic activities against different developmental stages of the barber's pole worm and other parasitic nematodes
- Preston, Sarah, Jiao, Yaqing, Baell, Jonathan, Keiser, Jennifer, Crawford, Simon, Koehler, Anson, Wang, Tao, Simpson, Moana, Kaplan, Ray, Cowley, Karla, Simpson, Kaylene, Hofmann, Andreas, Jabbar, Abdul, Gasser, Robin
- Authors: Preston, Sarah , Jiao, Yaqing , Baell, Jonathan , Keiser, Jennifer , Crawford, Simon , Koehler, Anson , Wang, Tao , Simpson, Moana , Kaplan, Ray , Cowley, Karla , Simpson, Kaylene , Hofmann, Andreas , Jabbar, Abdul , Gasser, Robin
- Date: 2017
- Type: Text , Journal article
- Relation: International Journal for Parasitology: Drugs and Drug Resistance Vol. 7, no. 3 (2017), p. 286-294
- Full Text:
- Reviewed:
- Description: The discovery and development of novel anthelmintic classes is essential to sustain the control of socioeconomically important parasitic worms of humans and animals. With the aim of offering novel, lead-like scaffolds for drug discovery, Compounds Australia released the ‘Open Scaffolds’ collection containing 33,999 compounds, with extensive information available on the physicochemical properties of these chemicals. In the present study, we screened 14,464 prioritised compounds from the ‘Open Scaffolds’ collection against the exsheathed third-stage larvae (xL3s) of Haemonchus contortus using recently developed whole-organism screening assays. We identified a hit compound, called SN00797439, which was shown to reproducibly reduce xL3 motility by ≥ 70%; this compound induced a characteristic, “coiled” xL3 phenotype (IC50 = 3.46–5.93 μM), inhibited motility of fourth-stage larvae (L4s; IC50 = 0.31–12.5 μM) and caused considerable cuticular damage to L4s in vitro. When tested on other parasitic nematodes in vitro, SN00797439 was shown to inhibit (IC50 = 3–50 μM) adults of Ancylostoma ceylanicum (hookworm) and first-stage larvae of Trichuris muris (whipworm) and eventually kill (>90%) these stages. Furthermore, this compound completely inhibited the motility of female and male adults of Brugia malayi (50–100 μM) as well as microfilariae of both B. malayi and Dirofilaria immitis (heartworm). Overall, these results show that SN00797439 acts against genetically (evolutionarily) distant parasitic nematodes i.e. H. contortus and A. ceylanicum [strongyloids] vs. B. malayi and D. immitis [filarioids] vs. T. muris [enoplid], and, thus, might offer a novel, lead-like scaffold for the development of a relatively broad-spectrum anthelmintic. Our future work will focus on assessing the activity of SN00797439 against other pathogens that cause neglected tropical diseases, optimising analogs with improved biological activities and characterising their targets. © 2017 The Authors
- Authors: Preston, Sarah , Jiao, Yaqing , Baell, Jonathan , Keiser, Jennifer , Crawford, Simon , Koehler, Anson , Wang, Tao , Simpson, Moana , Kaplan, Ray , Cowley, Karla , Simpson, Kaylene , Hofmann, Andreas , Jabbar, Abdul , Gasser, Robin
- Date: 2017
- Type: Text , Journal article
- Relation: International Journal for Parasitology: Drugs and Drug Resistance Vol. 7, no. 3 (2017), p. 286-294
- Full Text:
- Reviewed:
- Description: The discovery and development of novel anthelmintic classes is essential to sustain the control of socioeconomically important parasitic worms of humans and animals. With the aim of offering novel, lead-like scaffolds for drug discovery, Compounds Australia released the ‘Open Scaffolds’ collection containing 33,999 compounds, with extensive information available on the physicochemical properties of these chemicals. In the present study, we screened 14,464 prioritised compounds from the ‘Open Scaffolds’ collection against the exsheathed third-stage larvae (xL3s) of Haemonchus contortus using recently developed whole-organism screening assays. We identified a hit compound, called SN00797439, which was shown to reproducibly reduce xL3 motility by ≥ 70%; this compound induced a characteristic, “coiled” xL3 phenotype (IC50 = 3.46–5.93 μM), inhibited motility of fourth-stage larvae (L4s; IC50 = 0.31–12.5 μM) and caused considerable cuticular damage to L4s in vitro. When tested on other parasitic nematodes in vitro, SN00797439 was shown to inhibit (IC50 = 3–50 μM) adults of Ancylostoma ceylanicum (hookworm) and first-stage larvae of Trichuris muris (whipworm) and eventually kill (>90%) these stages. Furthermore, this compound completely inhibited the motility of female and male adults of Brugia malayi (50–100 μM) as well as microfilariae of both B. malayi and Dirofilaria immitis (heartworm). Overall, these results show that SN00797439 acts against genetically (evolutionarily) distant parasitic nematodes i.e. H. contortus and A. ceylanicum [strongyloids] vs. B. malayi and D. immitis [filarioids] vs. T. muris [enoplid], and, thus, might offer a novel, lead-like scaffold for the development of a relatively broad-spectrum anthelmintic. Our future work will focus on assessing the activity of SN00797439 against other pathogens that cause neglected tropical diseases, optimising analogs with improved biological activities and characterising their targets. © 2017 The Authors
Selected alpha-pyrones from the plants Cryptocarya novoguineensis (Lauraceae) and Piper methysticum (Piperaceae) with activity against Haemonchus contortus in vitro
- Herath, Dilrukshi, Preston, Sarah, Jabbar, Abdul, Garcia-Bustos, Jose, Addison, Russell, Hayes, Sasha, Rali, Topul, Wang, Tao, Koehler, Anson, Chang, Bill, Hofmann, Andreas, Davis, Rohan, Gasser, Robin
- Authors: Herath, Dilrukshi , Preston, Sarah , Jabbar, Abdul , Garcia-Bustos, Jose , Addison, Russell , Hayes, Sasha , Rali, Topul , Wang, Tao , Koehler, Anson , Chang, Bill , Hofmann, Andreas , Davis, Rohan , Gasser, Robin
- Date: 2019
- Type: Text , Journal article
- Relation: International Journal for Parasitology-Drugs and Drug Resistance Vol. 9, no. (2019), p. 72-79
- Full Text:
- Reviewed:
- Description: Due to the widespread occurrence and spread of anthelmintic resistance, there is a need to develop new drugs against resistant parasitic nematodes of livestock animals. The Nobel Prize-winning discovery and development of the anti-parasitic drugs avermectin and artemisinin has renewed the interest in exploring natural products as anthelmintics. In the present study, we screened 7500 plant extracts for in vitro-activity against the barber's pole worm, Haemonchus contortus, a highly significant pathogen of ruminants. The anthelmintic extracts from two plants, Cryptocarya novoguineensis and Piper methysticum, were fractionated by high-performance liquid chromatography (HPLC). Subsequently, compounds were purified from fractions with significant biological activity. Four alpha-pyrones, namely goniothalamin (GNT), dihydrokavain (DHK), desmethoxyyangonin (DMY) and yangonin (YGN), were purified from fractions from the two plants, GNT from C. novoguineensis, and DHK, DMY and YGN (= kavalactones) from P. methysticum. The three kavalactones induced a lethal, eviscerated (Evi) phenotype in treated exsheathed third-stage larvae (xL3s), and DMY and YGN had moderate potencies (IC50 values of 31.7 +/- 0.23 mu M and 23.7 +/- 2.05 mu M, respectively) at inhibiting the development of xL3s to fourth-stage larvae (L4s). Although GNT had limited potency (IC50 of 200-300 mu M) at inhibiting L4 development, it was the only compound that reduced L4 motility (IC50 of 6.25-12.50 mu M). The compounds purified from each plant affected H. contortus in an irreversible manner. These findings suggest that structure-activity relationship studies of alpha-pyrones should be pursued to assess their potential as anthelmintics.
- Authors: Herath, Dilrukshi , Preston, Sarah , Jabbar, Abdul , Garcia-Bustos, Jose , Addison, Russell , Hayes, Sasha , Rali, Topul , Wang, Tao , Koehler, Anson , Chang, Bill , Hofmann, Andreas , Davis, Rohan , Gasser, Robin
- Date: 2019
- Type: Text , Journal article
- Relation: International Journal for Parasitology-Drugs and Drug Resistance Vol. 9, no. (2019), p. 72-79
- Full Text:
- Reviewed:
- Description: Due to the widespread occurrence and spread of anthelmintic resistance, there is a need to develop new drugs against resistant parasitic nematodes of livestock animals. The Nobel Prize-winning discovery and development of the anti-parasitic drugs avermectin and artemisinin has renewed the interest in exploring natural products as anthelmintics. In the present study, we screened 7500 plant extracts for in vitro-activity against the barber's pole worm, Haemonchus contortus, a highly significant pathogen of ruminants. The anthelmintic extracts from two plants, Cryptocarya novoguineensis and Piper methysticum, were fractionated by high-performance liquid chromatography (HPLC). Subsequently, compounds were purified from fractions with significant biological activity. Four alpha-pyrones, namely goniothalamin (GNT), dihydrokavain (DHK), desmethoxyyangonin (DMY) and yangonin (YGN), were purified from fractions from the two plants, GNT from C. novoguineensis, and DHK, DMY and YGN (= kavalactones) from P. methysticum. The three kavalactones induced a lethal, eviscerated (Evi) phenotype in treated exsheathed third-stage larvae (xL3s), and DMY and YGN had moderate potencies (IC50 values of 31.7 +/- 0.23 mu M and 23.7 +/- 2.05 mu M, respectively) at inhibiting the development of xL3s to fourth-stage larvae (L4s). Although GNT had limited potency (IC50 of 200-300 mu M) at inhibiting L4 development, it was the only compound that reduced L4 motility (IC50 of 6.25-12.50 mu M). The compounds purified from each plant affected H. contortus in an irreversible manner. These findings suggest that structure-activity relationship studies of alpha-pyrones should be pursued to assess their potential as anthelmintics.
- Preston, Sarah, Luo, Junjie, Zhang, Yuezhou, Jabbar, Abdul, Crawford, Simon, Baell, Jonathan, Hofmann, Andreas, Hu, Min, Zhou, Hai-Bing, Gasser, Robin
- Authors: Preston, Sarah , Luo, Junjie , Zhang, Yuezhou , Jabbar, Abdul , Crawford, Simon , Baell, Jonathan , Hofmann, Andreas , Hu, Min , Zhou, Hai-Bing , Gasser, Robin
- Date: 2016
- Type: Text , Journal article
- Relation: Parasites & Vectors Vol. 9, no. 1 (2016), p. 346
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- Reviewed:
- Description: Parasitic worms represent a substantial disease burden in animals and humans worldwide. The control of parasitic roundworms (nematodes) relies heavily on the use of anthelmintic drugs. However, widespread drug resistance in nematodes seriously compromises the effectiveness of many anthelmintics around the world. Thus, there is a need to discover new drugs, with unique modes of action, against parasites.