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Lima C, Verdaguer IB, Wunderlich G, Katzin AM, Crabb BS, Gilson PR, Azevedo MF. Conditional expression of NanoLuc luciferase through a multimodular system offers rapid detection of antimalarial drug activity. Exp Parasitol 2023; 254:108620. [PMID: 37716462 DOI: 10.1016/j.exppara.2023.108620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 09/06/2023] [Accepted: 09/12/2023] [Indexed: 09/18/2023]
Abstract
Conditional gene expression is a powerful tool to investigate putative vaccine and drug targets, especially in a haploid organism such as Plasmodium falciparum. Inducible systems based on regulation of either transcription, translation, protein or mRNA stability, among others, allow switching on an off the expression of any desired gene causing specific gain or loss of function phenotypes. However, those systems can be cumbersome involving the construction of large plasmids and generation of multiple transgenic parasite lines. In addition, the dynamic range of regulation achieved is not predictable for each individual gene and can be insufficient to generate detectable phenotypes when the genes of interest are silenced. Here, we combined up to three distinct inducible systems to regulate the expression of a single gene. Expression of the reporter NanoLuc luciferase was regulated over 40-fold, which correlates to the regulation achieved by each individual system multiplied by each other. We applied the conditionally expressed NanoLuc to evaluate the effect of fast-acting antimalarials such as chloroquine and artesunate as well as of slower-acting ones such as atovaquone. The conditionally expressed reporter allowed faster and more reliable detection of toxicity to the parasite, which correlated to the expected action of each compound. Bioluminescence achieved by the expression of this inducible highly sensitive reporter is therefore a promising tool to investigate the temporal effect of potential new antimalarials. This single plasmid combination system might also prove useful to achieve sufficient regulation of genes of interest to produce loss-of-function phenotypes.
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Affiliation(s)
- Caroline Lima
- Federal University of Sao Paulo, Santos, Sao Paulo, Brazil
| | - Ignasi B Verdaguer
- Departamento de Parasitologia, Instituto de Ciência Biomédicas, Universidade de São Paulo, Avenida Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-900, Brazil
| | - Gerhard Wunderlich
- Departamento de Parasitologia, Instituto de Ciência Biomédicas, Universidade de São Paulo, Avenida Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-900, Brazil
| | - Alejandro M Katzin
- Departamento de Parasitologia, Instituto de Ciência Biomédicas, Universidade de São Paulo, Avenida Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-900, Brazil
| | - Brendan S Crabb
- Burnet Institute, Melbourne, VIC, 3004, Australia; University of Melbourne, VIC, 3052, Australia; Monash University, Melbourne, VIC, 3004, Australia
| | - Paul R Gilson
- Burnet Institute, Melbourne, VIC, 3004, Australia; University of Melbourne, VIC, 3052, Australia
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Xu J, Hu F, Li S, Bao J, Yin Y, Ren Z, Deng Y, Tian F, Bao G, Liu J, Li Y, He X, Xi J, Lu F. Fluorescent Nitrogen-Doped Carbon Dots for Label Live Elder Blood-Stage Plasmodium falciparum through New Permeability Pathways. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27134163. [PMID: 35807422 PMCID: PMC9267939 DOI: 10.3390/molecules27134163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/21/2022] [Accepted: 06/24/2022] [Indexed: 01/11/2023]
Abstract
To verify the size and emergence time of new permeability pathways (NPPs) in malaria parasites, the permeability of the Plasmodium falciparum-infected erythrocytes was tested with different particle sizes of nanomaterials by flow cytometry assay. The results confirmed the permeability of the host cell membrane increases with parasite maturation for the stage-development evolution of NPPs, and especially found that a particle size of about 50 nm had higher efficiency. As a kind of the novel nanomaterials, nitrogen-doped carbon dots (NCDs) showed no toxicity, specificity binding ability to the malaria parasites, and could label live elder blood-stage P. falciparum through NPPs, indicating the potential application in cell imaging. NPPs and some nanomaterials such as NCDs deserve more attention and exploration for the elimination and prevention of malaria.
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Affiliation(s)
- Jiahui Xu
- Jiangsu Key Laboratory of Experimental and Translational Non-Coding RNA Research, School of Medicine, Yangzhou University, Yangzhou 225009, China; (J.X.); (F.H.); (S.L.); (Y.Y.); (Z.R.); (Y.D.); (F.T.); (Y.L.); (X.H.)
- Affiliated Hospital of Yangzhou University, Yangzhou 225000, China; (J.B.); (G.B.); (J.L.)
| | - Fengyue Hu
- Jiangsu Key Laboratory of Experimental and Translational Non-Coding RNA Research, School of Medicine, Yangzhou University, Yangzhou 225009, China; (J.X.); (F.H.); (S.L.); (Y.Y.); (Z.R.); (Y.D.); (F.T.); (Y.L.); (X.H.)
- The Third People’s Hospital of Yangzhou, Yangzhou 225012, China
| | - Shuang Li
- Jiangsu Key Laboratory of Experimental and Translational Non-Coding RNA Research, School of Medicine, Yangzhou University, Yangzhou 225009, China; (J.X.); (F.H.); (S.L.); (Y.Y.); (Z.R.); (Y.D.); (F.T.); (Y.L.); (X.H.)
| | - Jiaojiao Bao
- Affiliated Hospital of Yangzhou University, Yangzhou 225000, China; (J.B.); (G.B.); (J.L.)
| | - Yi Yin
- Jiangsu Key Laboratory of Experimental and Translational Non-Coding RNA Research, School of Medicine, Yangzhou University, Yangzhou 225009, China; (J.X.); (F.H.); (S.L.); (Y.Y.); (Z.R.); (Y.D.); (F.T.); (Y.L.); (X.H.)
| | - Zhenyu Ren
- Jiangsu Key Laboratory of Experimental and Translational Non-Coding RNA Research, School of Medicine, Yangzhou University, Yangzhou 225009, China; (J.X.); (F.H.); (S.L.); (Y.Y.); (Z.R.); (Y.D.); (F.T.); (Y.L.); (X.H.)
| | - Ying Deng
- Jiangsu Key Laboratory of Experimental and Translational Non-Coding RNA Research, School of Medicine, Yangzhou University, Yangzhou 225009, China; (J.X.); (F.H.); (S.L.); (Y.Y.); (Z.R.); (Y.D.); (F.T.); (Y.L.); (X.H.)
| | - Fang Tian
- Jiangsu Key Laboratory of Experimental and Translational Non-Coding RNA Research, School of Medicine, Yangzhou University, Yangzhou 225009, China; (J.X.); (F.H.); (S.L.); (Y.Y.); (Z.R.); (Y.D.); (F.T.); (Y.L.); (X.H.)
| | - Guangyu Bao
- Affiliated Hospital of Yangzhou University, Yangzhou 225000, China; (J.B.); (G.B.); (J.L.)
| | - Jian Liu
- Affiliated Hospital of Yangzhou University, Yangzhou 225000, China; (J.B.); (G.B.); (J.L.)
| | - Yinyue Li
- Jiangsu Key Laboratory of Experimental and Translational Non-Coding RNA Research, School of Medicine, Yangzhou University, Yangzhou 225009, China; (J.X.); (F.H.); (S.L.); (Y.Y.); (Z.R.); (Y.D.); (F.T.); (Y.L.); (X.H.)
| | - Xinlong He
- Jiangsu Key Laboratory of Experimental and Translational Non-Coding RNA Research, School of Medicine, Yangzhou University, Yangzhou 225009, China; (J.X.); (F.H.); (S.L.); (Y.Y.); (Z.R.); (Y.D.); (F.T.); (Y.L.); (X.H.)
| | - Juqun Xi
- Jiangsu Key Laboratory of Experimental and Translational Non-Coding RNA Research, School of Medicine, Yangzhou University, Yangzhou 225009, China; (J.X.); (F.H.); (S.L.); (Y.Y.); (Z.R.); (Y.D.); (F.T.); (Y.L.); (X.H.)
- Correspondence: (J.X.); (F.L.)
| | - Feng Lu
- Jiangsu Key Laboratory of Experimental and Translational Non-Coding RNA Research, School of Medicine, Yangzhou University, Yangzhou 225009, China; (J.X.); (F.H.); (S.L.); (Y.Y.); (Z.R.); (Y.D.); (F.T.); (Y.L.); (X.H.)
- Affiliated Hospital of Yangzhou University, Yangzhou 225000, China; (J.B.); (G.B.); (J.L.)
- Jiangsu Key Laboratory of Zoonosis, Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
- Correspondence: (J.X.); (F.L.)
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Gabriela M, Matthews KM, Boshoven C, Kouskousis B, Jonsdottir TK, Bullen HE, Modak J, Steer DL, Sleebs BE, Crabb BS, de Koning-Ward TF, Gilson PR. A revised mechanism for how Plasmodium falciparum recruits and exports proteins into its erythrocytic host cell. PLoS Pathog 2022; 18:e1009977. [PMID: 35192672 PMCID: PMC8896661 DOI: 10.1371/journal.ppat.1009977] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 03/04/2022] [Accepted: 02/10/2022] [Indexed: 11/18/2022] Open
Abstract
Plasmodium falciparum exports ~10% of its proteome into its host erythrocyte to modify the host cell's physiology. The Plasmodium export element (PEXEL) motif contained within the N-terminus of most exported proteins directs the trafficking of those proteins into the erythrocyte. To reach the host cell, the PEXEL motif of exported proteins is processed by the endoplasmic reticulum (ER) resident aspartyl protease plasmepsin V. Then, following secretion into the parasite-encasing parasitophorous vacuole, the mature exported protein must be unfolded and translocated across the parasitophorous vacuole membrane by the Plasmodium translocon of exported proteins (PTEX). PTEX is a protein-conducting channel consisting of the pore-forming protein EXP2, the protein unfoldase HSP101, and structural component PTEX150. The mechanism of how exported proteins are specifically trafficked from the parasite's ER following PEXEL cleavage to PTEX complexes on the parasitophorous vacuole membrane is currently not understood. Here, we present evidence that EXP2 and PTEX150 form a stable subcomplex that facilitates HSP101 docking. We also demonstrate that HSP101 localises both within the parasitophorous vacuole and within the parasite's ER throughout the ring and trophozoite stage of the parasite, coinciding with the timeframe of protein export. Interestingly, we found that HSP101 can form specific interactions with model PEXEL proteins in the parasite's ER, irrespective of their PEXEL processing status. Collectively, our data suggest that HSP101 recognises and chaperones PEXEL proteins from the ER to the parasitophorous vacuole and given HSP101's specificity for the EXP2-PTEX150 subcomplex, this provides a mechanism for how exported proteins are specifically targeted to PTEX for translocation into the erythrocyte.
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Affiliation(s)
- Mikha Gabriela
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- School of Medicine, Deakin University, Geelong, Australia
| | - Kathryn M. Matthews
- School of Medicine, Deakin University, Geelong, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, Australia
| | - Cas Boshoven
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
| | - Betty Kouskousis
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
| | - Thorey K. Jonsdottir
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
| | - Hayley E. Bullen
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
| | - Joyanta Modak
- School of Medicine, Deakin University, Geelong, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, Australia
| | - David L. Steer
- Monash Biomedical Proteomics and Metabolomics Facility, Monash University, Melbourne, Australia
| | - Brad E. Sleebs
- ACRF Chemical Biology Division, Walter and Eliza Hall Institute, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, Australia
| | - Brendan S. Crabb
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
- Department of Immunology and Pathology, Monash University, Melbourne, Australia
| | - Tania F. de Koning-Ward
- School of Medicine, Deakin University, Geelong, Australia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, Australia
| | - Paul R. Gilson
- Malaria Virulence and Drug Discovery Group, Burnet Institute, Melbourne, Australia
- Department of Immunology and Microbiology, University of Melbourne, Melbourne, Australia
- * E-mail:
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Ullah I, Sharma R, Mete A, Biagini GA, Wetzel DM, Horrocks PD. The relative rate of kill of the MMV Malaria Box compounds provides links to the mode of antimalarial action and highlights scaffolds of medicinal chemistry interest. J Antimicrob Chemother 2021; 75:362-370. [PMID: 31665424 DOI: 10.1093/jac/dkz443] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/04/2019] [Accepted: 10/01/2019] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Rapid rate-of-kill (RoK) is a key parameter in the target candidate profile 1 (TCP1) for the next-generation antimalarial drugs for uncomplicated malaria, termed Single Encounter Radical Cure and Prophylaxis (SERCaP). TCP1 aims to rapidly eliminate the initial parasite burden, ideally as fast as artesunate, but minimally as fast as chloroquine. Here we explore whether the relative RoK of the Medicine for Malaria Venture (MMV) Malaria Box compounds is linked to their mode of action (MoA) and identify scaffolds of medicinal chemistry interest. METHODS We used a bioluminescence relative RoK (BRRoK) assay over 6 and 48 h, with exposure to equipotent IC50 concentrations, to compare the cytocidal effects of Malaria Box compounds with those of benchmark antimalarials. RESULTS BRRoK assay data demonstrate the following relative RoKs, from fast to slow: inhibitors of PfATP4>parasite haemoglobin catabolism>dihydrofolate reductase-thymidylate synthase (DHFR-TS)>dihydroorotate dehydrogenase (DHODH)>bc1 complex. Core-scaffold clustering analyses revealed intrinsic rapid cytocidal action for diamino-glycerols and 2-(aminomethyl)phenol, but slow action for 2-phenylbenz-imidazoles, 8-hydroxyquinolines and triazolopyrimidines. CONCLUSIONS This study provides proof of principle that a compound's RoK is related to its MoA and that the target's intrinsic RoK is also modified by factors affecting a drug's access to it. Our findings highlight that as we use medicinal chemistry to improve potency, we can also improve the RoK for some scaffolds. Our BRRoK assay provides the necessary throughput for drug discovery and a critical decision-making tool to support development campaigns. Finally, two scaffolds, diamino-glycerols and 2-phenylbenzimidazoles, exhibit fast cytocidal action, inviting medicinal chemistry improvements towards TCP1 candidates.
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Affiliation(s)
- Imran Ullah
- Institute for Science and Technology in Medicine, Keele University, Staffordshire, UK
| | - Raman Sharma
- Research Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Antonio Mete
- Medsyndesign Ltd, Advanced Technology Innovation Centre, 5 Oakwood Drive, Loughborough, UK
| | - Giancarlo A Biagini
- Research Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Dawn M Wetzel
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Paul D Horrocks
- Institute for Science and Technology in Medicine, Keele University, Staffordshire, UK
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5
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Moraes Barros RR, Thawnashom K, Gibson TJ, Armistead JS, Caleon RL, Kaneko M, Kite WA, Mershon JP, Brockhurst JK, Engels T, Lambert L, Orr-Gonzalez S, Adams JH, Sá JM, Kaneko O, Wellems TE. Activity of Plasmodium vivax promoter elements in Plasmodium knowlesi, and a centromere-containing plasmid that expresses NanoLuc throughout the parasite life cycle. Malar J 2021; 20:247. [PMID: 34090438 PMCID: PMC8180018 DOI: 10.1186/s12936-021-03773-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 05/16/2021] [Indexed: 12/23/2022] Open
Abstract
Background Plasmodium knowlesi is now the major cause of human malaria in Malaysia, complicating malaria control efforts that must attend to the elimination of multiple Plasmodium species. Recent advances in the cultivation of P. knowlesi erythrocytic-stage parasites in vitro, transformation with exogenous DNA, and infection of mosquitoes with gametocytes from culture have opened up studies of this pathogen without the need for resource-intensive and costly non-human primate (NHP) models. For further understanding and development of methods for parasite transformation in malaria research, this study examined the activity of various trans-species transcriptional control sequences and the influence of Plasmodium vivax centromeric (pvcen) repeats in plasmid-transfected P. knowlesi parasites. Methods In vitro cultivated P. knowlesi parasites were transfected with plasmid constructs that incorporated Plasmodium vivax or Plasmodium falciparum 5′ UTRs driving the expression of bioluminescence markers (firefly luciferase or Nanoluc). Promoter activities were assessed by bioluminescence, and parasites transformed with human resistant allele dihydrofolate reductase-expressing plasmids were selected using antifolates. The stability of transformants carrying pvcen-stabilized episomes was assessed by bioluminescence over a complete parasite life cycle through a rhesus macaque monkey, mosquitoes, and a second rhesus monkey. Results Luciferase expression assessments show that certain P. vivax promoter regions, not functional in the more evolutionarily-distant P. falciparum, can drive transgene expression in P. knowlesi. Further, pvcen repeats may improve the stability of episomal plasmids in P. knowlesi and support detection of NanoLuc-expressing elements over the full parasite life cycle from rhesus macaque monkeys to Anopheles dirus mosquitoes and back again to monkeys. In assays of drug responses to chloroquine, G418 and WR9910, anti-malarial half-inhibitory concentration (IC50) values of blood stages measured by NanoLuc activity proved comparable to IC50 values measured by the standard SYBR Green method. Conclusion All three P. vivax promoters tested in this study functioned in P. knowlesi, whereas two of the three were inactive in P. falciparum. NanoLuc-expressing, centromere-stabilized plasmids may support high-throughput screenings of P. knowlesi for new anti-malarial agents, including compounds that can block the development of mosquito- and/or liver-stage parasites. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03773-4.
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Affiliation(s)
- Roberto R Moraes Barros
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA. .,Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil.
| | - Kittisak Thawnashom
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan.,Department of Medical Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand
| | - Tyler J Gibson
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Jennifer S Armistead
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.,Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, FL, USA
| | - Ramoncito L Caleon
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Miho Kaneko
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan.,Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Whitney A Kite
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - J Patrick Mershon
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Jacqueline K Brockhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Theresa Engels
- Division of Veterinary Research, National Institutes of Health, Bethesda, MD, USA
| | - Lynn Lambert
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Sachy Orr-Gonzalez
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - John H Adams
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, FL, USA
| | - Juliana M Sá
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Osamu Kaneko
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Thomas E Wellems
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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Hameed H, King EFB, Doleckova K, Bartholomew B, Hollinshead J, Mbye H, Ullah I, Walker K, Van Veelen M, Abou-Akkada SS, Nash RJ, Horrocks PD, Price HP. Temperate Zone Plant Natural Products-A Novel Resource for Activity against Tropical Parasitic Diseases. Pharmaceuticals (Basel) 2021; 14:227. [PMID: 33800005 PMCID: PMC7998250 DOI: 10.3390/ph14030227] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/22/2021] [Accepted: 03/03/2021] [Indexed: 11/16/2022] Open
Abstract
The use of plant-derived natural products for the treatment of tropical parasitic diseases often has ethnopharmacological origins. As such, plants grown in temperate regions remain largely untested for novel anti-parasitic activities. We describe here a screen of the PhytoQuest Phytopure library, a novel source comprising over 600 purified compounds from temperate zone plants, against in vitro culture systems for Plasmodium falciparum, Leishmania mexicana, Trypanosoma evansi and T. brucei. Initial screen revealed 6, 65, 15 and 18 compounds, respectively, that decreased each parasite's growth by at least 50% at 1-2 µM concentration. These initial hits were validated in concentration-response assays against the parasite and the human HepG2 cell line, identifying hits with EC50 < 1 μM and a selectivity index of >10. Two sesquiterpene glycosides were identified against P. falciparum, four sterols against L. mexicana, and five compounds of various scaffolds against T. brucei and T. evansi. An L. mexicana resistant line was generated for the sterol 700022, which was found to have cross-resistance to the anti-leishmanial drug miltefosine as well as to the other leishmanicidal sterols. This study highlights the potential of a temperate plant secondary metabolites as a novel source of natural products against tropical parasitic diseases.
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Affiliation(s)
- Hamza Hameed
- Centre for Applied Entomology and Parasitology, Keele University, Staffordshire ST5 5BG, UK; (H.H.); (E.F.B.K.); (K.D.); (H.M.); (I.U.); (M.V.V.)
- Department of Chemistry, College of Education for Pure Science, University of Mosul, Mosul, Iraq
| | - Elizabeth F. B. King
- Centre for Applied Entomology and Parasitology, Keele University, Staffordshire ST5 5BG, UK; (H.H.); (E.F.B.K.); (K.D.); (H.M.); (I.U.); (M.V.V.)
| | - Katerina Doleckova
- Centre for Applied Entomology and Parasitology, Keele University, Staffordshire ST5 5BG, UK; (H.H.); (E.F.B.K.); (K.D.); (H.M.); (I.U.); (M.V.V.)
- Department of Biology, Faculty of Life Sciences, University of Hradec Králové, 500 03 Hradec Králové, Czech Republic
| | | | | | - Haddijatou Mbye
- Centre for Applied Entomology and Parasitology, Keele University, Staffordshire ST5 5BG, UK; (H.H.); (E.F.B.K.); (K.D.); (H.M.); (I.U.); (M.V.V.)
- MRC Unit The Gambia at LSHTM, Atlantic Boulevard, Fajara, Banjul PO Box 273, The Gambia
| | - Imran Ullah
- Centre for Applied Entomology and Parasitology, Keele University, Staffordshire ST5 5BG, UK; (H.H.); (E.F.B.K.); (K.D.); (H.M.); (I.U.); (M.V.V.)
- Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA 02115, USA
| | - Karen Walker
- School of Life Sciences, Keele University, Staffordshire ST5 5BG, UK;
| | - Maria Van Veelen
- Centre for Applied Entomology and Parasitology, Keele University, Staffordshire ST5 5BG, UK; (H.H.); (E.F.B.K.); (K.D.); (H.M.); (I.U.); (M.V.V.)
| | | | - Robert J. Nash
- PhytoQuest Limited, Aberystwyth SY23 3EB, UK; (B.B.); (J.H.); (R.J.N.)
| | - Paul D. Horrocks
- Centre for Applied Entomology and Parasitology, Keele University, Staffordshire ST5 5BG, UK; (H.H.); (E.F.B.K.); (K.D.); (H.M.); (I.U.); (M.V.V.)
| | - Helen P. Price
- Centre for Applied Entomology and Parasitology, Keele University, Staffordshire ST5 5BG, UK; (H.H.); (E.F.B.K.); (K.D.); (H.M.); (I.U.); (M.V.V.)
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7
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Ellinger B, Pohlmann D, Woens J, Jäkel FM, Reinshagen J, Stocking C, Prassolov VS, Fehse B, Riecken K. A High-Throughput HIV-1 Drug Screening Platform, Based on Lentiviral Vectors and Compatible with Biosafety Level-1. Viruses 2020; 12:E580. [PMID: 32466195 PMCID: PMC7290285 DOI: 10.3390/v12050580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 11/17/2022] Open
Abstract
HIV-1 infection is a complex, multi-step process involving not only viral, but also multiple cellular factors. To date, drug discovery methods have primarily focused on the inhibition of single viral proteins. We present an efficient and unbiased approach, compatible with biosafety level 1 (BSL-1) conditions, to identify inhibitors of HIV-1 reverse transcription, intracellular trafficking, nuclear entry and genome integration. Starting with a fluorescent assay setup, we systematically improved the screening methodology in terms of stability, efficiency and pharmacological relevance. Stability and throughput were optimized by switching to a luciferase-based readout. BSL-1 compliance was achieved without sacrificing pharmacological relevance by using lentiviral particles pseudo-typed with the mouse ecotropic envelope protein to transduce human PM1 T cells gene-modified to express the corresponding murine receptor. The cellular assay was used to screen 26,048 compounds selected for maximum diversity from a 200,640-compound in-house library. This yielded z' values greater than 0.8 with a hit rate of 3.3% and a confirmation rate of 50%. We selected 93 hits and enriched the collection with 279 similar compounds from the in-house library to identify promising structural features. The most active compounds were validated using orthogonal assay formats. The similarity of the compound profiles across the different platforms demonstrated that the reported lentiviral assay system is a robust and versatile tool for the identification of novel HIV-1 inhibitors.
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Affiliation(s)
- Bernhard Ellinger
- Department ScreeningPort, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, 22525 Hamburg, Germany; (B.E.); (J.R.)
- Fraunhofer Cluster of Excellence Immune-Mediated Diseases CIMD, Partner site Hamburg, 22525 Hamburg, Germany
| | - Daniel Pohlmann
- Research Department Cell and Gene Therapy, Department of Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany; (D.P.); (J.W.); (F.M.J.); (C.S.)
| | - Jannis Woens
- Research Department Cell and Gene Therapy, Department of Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany; (D.P.); (J.W.); (F.M.J.); (C.S.)
| | - Felix M. Jäkel
- Research Department Cell and Gene Therapy, Department of Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany; (D.P.); (J.W.); (F.M.J.); (C.S.)
| | - Jeanette Reinshagen
- Department ScreeningPort, Fraunhofer Institute for Molecular Biology and Applied Ecology IME, 22525 Hamburg, Germany; (B.E.); (J.R.)
- Fraunhofer Cluster of Excellence Immune-Mediated Diseases CIMD, Partner site Hamburg, 22525 Hamburg, Germany
| | - Carol Stocking
- Research Department Cell and Gene Therapy, Department of Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany; (D.P.); (J.W.); (F.M.J.); (C.S.)
- Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, 20251 Hamburg, Germany
| | - Vladimir S. Prassolov
- Engelhardt-Institute of Molecular Biology, Russian Academy of Sciences, 117984 Moscow, Russia;
| | - Boris Fehse
- Research Department Cell and Gene Therapy, Department of Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany; (D.P.); (J.W.); (F.M.J.); (C.S.)
- German Center for Infection Research (DZIF), Partner site Hamburg, 20246 Hamburg, Germany
| | - Kristoffer Riecken
- Research Department Cell and Gene Therapy, Department of Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany; (D.P.); (J.W.); (F.M.J.); (C.S.)
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Álvarez-Bardón M, Pérez-Pertejo Y, Ordóñez C, Sepúlveda-Crespo D, Carballeira NM, Tekwani BL, Murugesan S, Martinez-Valladares M, García-Estrada C, Reguera RM, Balaña-Fouce R. Screening Marine Natural Products for New Drug Leads against Trypanosomatids and Malaria. Mar Drugs 2020; 18:E187. [PMID: 32244488 PMCID: PMC7230869 DOI: 10.3390/md18040187] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 02/06/2023] Open
Abstract
Neglected Tropical Diseases (NTD) represent a serious threat to humans, especially for those living in poor or developing countries. Almost one-sixth of the world population is at risk of suffering from these diseases and many thousands die because of NTDs, to which we should add the sanitary, labor and social issues that hinder the economic development of these countries. Protozoan-borne diseases are responsible for more than one million deaths every year. Visceral leishmaniasis, Chagas disease or sleeping sickness are among the most lethal NTDs. Despite not being considered an NTD by the World Health Organization (WHO), malaria must be added to this sinister group. Malaria, caused by the apicomplexan parasite Plasmodium falciparum, is responsible for thousands of deaths each year. The treatment of this disease has been losing effectiveness year after year. Many of the medicines currently in use are obsolete due to their gradual loss of efficacy, their intrinsic toxicity and the emergence of drug resistance or a lack of adherence to treatment. Therefore, there is an urgent and global need for new drugs. Despite this, the scant interest shown by most of the stakeholders involved in the pharmaceutical industry makes our present therapeutic arsenal scarce, and until recently, the search for new drugs has not been seriously addressed. The sources of new drugs for these and other pathologies include natural products, synthetic molecules or repurposing drugs. The most frequent sources of natural products are microorganisms, e.g., bacteria, fungi, yeasts, algae and plants, which are able to synthesize many drugs that are currently in use (e.g. antimicrobials, antitumor, immunosuppressants, etc.). The marine environment is another well-established source of bioactive natural products, with recent applications against parasites, bacteria and other pathogens which affect humans and animals. Drug discovery techniques have rapidly advanced since the beginning of the millennium. The combination of novel techniques that include the genetic modification of pathogens, bioimaging and robotics has given rise to the standardization of High-Performance Screening platforms in the discovery of drugs. These advancements have accelerated the discovery of new chemical entities with antiparasitic effects. This review presents critical updates regarding the use of High-Throughput Screening (HTS) in the discovery of drugs for NTDs transmitted by protozoa, including malaria, and its application in the discovery of new drugs of marine origin.
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Affiliation(s)
- María Álvarez-Bardón
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - Yolanda Pérez-Pertejo
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - César Ordóñez
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - Daniel Sepúlveda-Crespo
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - Nestor M. Carballeira
- Department of Chemistry, University of Puerto Rico, Río Piedras 00925-2537, San Juan, Puerto Rico;
| | - Babu L. Tekwani
- Department of Infectious Diseases, Division of Drug Discovery, Southern Research, Birmingham, AL 35205, USA;
| | - Sankaranarayanan Murugesan
- Department of Pharmacy, Birla Institute of Technology and Science, Pilani Campus, Vidya Vihar, Pilani 333031, India;
| | - Maria Martinez-Valladares
- Department of Animal Health, Instituto de Ganadería de Montaña (CSIC-Universidad de León), Grulleros, 24346 León, Spain;
| | - Carlos García-Estrada
- INBIOTEC (Instituto de Biotecnología de León), Avda. Real 1-Parque Científico de León, 24006 León, Spain;
| | - Rosa M. Reguera
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
| | - Rafael Balaña-Fouce
- Department of Biomedical Sciences; University of León, 24071 León, Spain; (M.Á.-B.); (Y.P.-P.); (C.O.); (D.S.-C.); (R.M.R.)
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9
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Berry SL, Hameed H, Thomason A, Maciej-Hulme ML, Saif Abou-Akkada S, Horrocks P, Price HP. Development of NanoLuc-PEST expressing Leishmania mexicana as a new drug discovery tool for axenic- and intramacrophage-based assays. PLoS Negl Trop Dis 2018; 12:e0006639. [PMID: 30001317 PMCID: PMC6057649 DOI: 10.1371/journal.pntd.0006639] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 07/24/2018] [Accepted: 06/26/2018] [Indexed: 12/12/2022] Open
Abstract
The protozoan parasite Leishmania causes leishmaniasis; a spectrum of diseases of which there are an estimated 1 million new cases each year. Current treatments are toxic, expensive, difficult to administer, and resistance to them is emerging. New therapeutics are urgently needed, however, screening the infective amastigote form of the parasite is challenging. Only certain species can be differentiated into axenic amastigotes, and compound activity against these does not always correlate with efficacy against the parasite in its intracellular niche. Methods used to assess compound efficacy on intracellular amastigotes often rely on microscopy-based assays. These are laborious, require specialist equipment and can only determine parasite burden, not parasite viability. We have addressed this clear need in the anti-leishmanial drug discovery process by producing a transgenic L. mexicana cell line that expresses the luciferase NanoLuc-PEST. We tested the sensitivity and versatility of this transgenic strain, in comparison with strains expressing NanoLuc and the red-shifted firefly luciferase. We then compared the NanoLuc-PEST luciferase to the current methods in both axenic and intramacrophage amastigotes following treatment with a supralethal dose of Amphotericin B. NanoLuc-PEST was a more dynamic indicator of cell viability due to its high turnover rate and high signal:background ratio. This, coupled with its sensitivity in the intramacrophage assay, led us to validate the NanoLuc-PEST expressing cell line using the MMV Pathogen Box in a two-step process: i) identify hits against axenic amastigotes, ii) screen these hits using our bioluminescence-based intramacrophage assay. The data obtained from this highlights the potential of compounds active against M. tuberculosis to be re-purposed for use against Leishmania. Our transgenic L. mexicana cell line is therefore a highly sensitive and dynamic system suitable for Leishmania drug discovery in axenic and intramacrophage amastigote models. The protozoan parasite Leishmania causes a spectrum of diseases collectively known as leishmaniasis. The parasite is transmitted to humans by the bite of its vector, the sand fly, following which the parasite invades host white blood cells, particularly macrophages. Leishmaniasis is classified as a neglected tropical disease, and is endemic in 97 countries. Symptoms of the disease depend on the species of Leishmania. These include skin lesions, destruction of the mucosal membranes, and the visceral form which is usually fatal if untreated. Current therapeutic options for leishmaniasis have a number of associated problems that include toxicity, the development of drug resistance and poor patient compliance due to lengthy and painful treatment regimens. New therapeutics are therefore urgently needed. The ability to screen potential drug candidates requires robust screening assays. Currently, screening the intracellular parasite relies on microscopy-based techniques that require expensive equipment, are time consuming and only detect parasite burden, not viability. By using a transgenic cell line that expresses the NanoLuc-PEST luciferase, we show that we have a parasite-specific viability marker that can be used to measure the efficacy of compounds against the intracellular parasite. We validate the potential of this cell line by screening the MMV Pathogen Box.
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Affiliation(s)
- Sarah L. Berry
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Newcastle-under-Lyme, Staffordshire, United Kingdom
| | - Hamza Hameed
- Institute for Science and Technology in Medicine, Keele University, Newcastle-under-Lyme, Staffordshire, United Kingdom
| | - Anna Thomason
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Newcastle-under-Lyme, Staffordshire, United Kingdom
- Current address: School of Environment and Life Sciences, University of Salford, Salford, United Kingdom
| | - Marissa L. Maciej-Hulme
- Radboud University Medical Center, Department of Nephrology, Geert Grooteplein 10, GA Nijmegan, The Netherlands
| | - Somaia Saif Abou-Akkada
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Newcastle-under-Lyme, Staffordshire, United Kingdom
- Faculty of Veterinary Medicine, Alexandria University, Alexandria, Egypt
| | - Paul Horrocks
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Newcastle-under-Lyme, Staffordshire, United Kingdom
- Institute for Science and Technology in Medicine, Keele University, Newcastle-under-Lyme, Staffordshire, United Kingdom
| | - Helen P. Price
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Newcastle-under-Lyme, Staffordshire, United Kingdom
- * E-mail:
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10
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Rizk MA, El-Sayed SAES, AbouLaila M, Eltaysh R, Yokoyama N, Igarashi I. Performance and consistency of a fluorescence-based high-throughput screening assay for use in Babesia drug screening in mice. Sci Rep 2017; 7:12774. [PMID: 29038534 PMCID: PMC5643553 DOI: 10.1038/s41598-017-13052-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 09/18/2017] [Indexed: 12/02/2022] Open
Abstract
In this study, we evaluated the validity of a fluorescence-based assay using SYBR Green I (SG I) stain for screening antibabesial compounds against B. microti in mice. Two different hematocrits (HCTs; 2.5% and 5%) were used. Correlating relative fluorescence units (RFUs) with parasitemia showed significant linear relationships with R2 values of 0.97 and 0.99 at HCTs of 2.5% and 5%, respectively. Meanwhile, the Z′ factors in a high-throughput screening (HTS) assay were within the permissible limit (≥0.5) at 2.5% HCT and lower than this value at 5% HCT. Taken together, the highest signal-to-noise (S/N) ratios were obtained at 2.5% HCT; therefore, we concluded that 2.5% was the best HCT for applying fluorescence assay in antibabesial drug screening in mice. Additionally, positive control mice and those treated with diminazene aceturate, pyronaridine tetraphosphate, and an allicin/diminazene aceturate combination showed peak parasitemia and fluorescence values on the same day post-inoculation. Moreover, using different concentrations of SG I revealed that the optimal concentration was 2x. In summary, considering that all experiments were applied under optimal laboratory conditions, fluorescence assay at 2.5% HCT using 2x SG I for B. microti parasite offers a novel approach for drug screening in mice.
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Affiliation(s)
- Mohamed Abdo Rizk
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, 080-8555, Japan.,Department of Internal Medicine and Infectious Diseases, Faculty of Veterinary Medicine, Mansoura University, Mansoura, 35516, Egypt
| | - Shimaa Abd El-Salam El-Sayed
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, 080-8555, Japan.,Department of Biochemistry and Chemistry of Nutrition, Faculty of Veterinary Medicine, Mansoura University, Mansoura, 35516, Egypt
| | - Mahmoud AbouLaila
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, 080-8555, Japan.,Department of Parasitology, Faculty of Veterinary Medicine, University of Sadat City, Sadat City, 32511, Minoufiya, Egypt
| | - Rasha Eltaysh
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, 080-8555, Japan.,Department of Pharmacology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, 35516, Egypt
| | - Naoaki Yokoyama
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, 080-8555, Japan
| | - Ikuo Igarashi
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, 080-8555, Japan.
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11
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Ullah I, Sharma R, Biagini GA, Horrocks P. A validated bioluminescence-based assay for the rapid determination of the initial rate of kill for discovery antimalarials. J Antimicrob Chemother 2017; 72:717-726. [PMID: 27999014 DOI: 10.1093/jac/dkw449] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/22/2016] [Indexed: 11/13/2022] Open
Abstract
Objectives A future treatment for uncomplicated malaria will contain at least one component that exerts a rapid rate of kill. We describe here the validation and application of a simple, robust and rapid bioluminescence-based assay for the determination of the initial rate of kill in intra-erythrocytic asexual stages of Plasmodium falciparum . Methods A modification to the concentration-response bioluminescence [here termed bioluminescence relative rate of kill (BRRoK)] assay, utilizing exposure to fold-IC 50 concentrations (0.33× to 9×), was used to monitor the immediate cytocidal effect of 372 open-source compounds for antimalarial drug discovery available through the Medicines for Malaria Venture Malaria Box. Results Antimalarial drugs that exert a rapid cytocidal effect produce a concentration-dependent loss of bioluminescence signal that correlates with available in vitro and in vivo estimates of parasite clearance time and parasite reduction ratio. Following the measurement of IC 50 for the Malaria Box compounds in Dd2 luc , the BRRoK assay was used to identify and rank 372 compounds for their initial cytocidal activity. Fifty-three compounds in the Malaria Box show an initial relative rate of kill greater than that of chloroquine, with 17 of these having an initial relative rate of kill greater than that of dihydroartemisinin. Conclusions The BRRoK assay provides a rapid assay format for the estimation of a key pharmacodynamic property of antimalarial drug action. The simplicity and robustness of the assay suggests it would be readily scalable for high-throughput screening and a critical decision-making tool for antimalarial drug development.
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Affiliation(s)
- Imran Ullah
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK
| | - Raman Sharma
- Research Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Giancarlo A Biagini
- Research Centre for Drugs and Diagnostics, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Paul Horrocks
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK
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12
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Aldulaimi O, Uche FI, Hameed H, Mbye H, Ullah I, Drijfhout F, Claridge TDW, Horrocks P, Li WW. A characterization of the antimalarial activity of the bark of Cylicodiscus gabunensis Harms. JOURNAL OF ETHNOPHARMACOLOGY 2017; 198:221-225. [PMID: 28089716 DOI: 10.1016/j.jep.2017.01.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/19/2016] [Accepted: 01/09/2017] [Indexed: 06/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE AND AIM A decoction of the bark of Cylicodiscus gabunensis Harms is used as a traditional medicine in the treatment of malaria in Nigeria. This study aims to validate the antimalarial potency of this decoction in vitro against Plasmodium falciparum and define potential bioactive constituents within the C. gabunensis bark. MATERIALS AND METHODS A bioassay-guided separation and fractionation protocol was applied to C. gabunensis extracts, exploiting the use of a Malaria Sybr Green I Fluorescence assay method to monitor antiproliferative effects on parasites as well as define 50% inhibition concentrations. Spectroscopic techniques, including GC-MS, TOF LC-MS and 1H NMR were used to identify phytochemicals present in bioactive fractions. Analogues of gallic acid were synthesized de novo to support the demonstration of the antimalarial action of phenolic acids identified in C. gabunensis bark. In vitro cytotoxicity of plant extracts, fractions and gallate analogues was evaluated against the HepG2 cell line. RESULTS The antimalarial activity of ethanolic extracts of C. gabunensis bark was confirmed in vitro, with evidence for phenolic acids, primarily gallic acid and close analogues such as ethyl gallate, likely providing this effect. Further fractionation produced the most potent fraction with a 50% inhibitory concentration of 4.7µg/ml. Spectroscopic analysis, including 1H NMR, LC-MS and GC-MS analysis of this fraction and its acid hydrolyzed products, indicated the presence of conjugates of gallic acid with oligosaccharides. The extracts/fractions and synthetic alkyl and alkenyl gallates showed moderate selectivity against P. falciparum. CONCLUSIONS These results support the use of the bark of C. gabunensis as a traditional medicine in the treatment of human malaria, with phenolic acid oligosaccharide complexes evident in the most bioactive fractions.
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Affiliation(s)
- Omar Aldulaimi
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, United Kingdom; College of Pharmacy, Al-Mustansiriyah University, Baghdad, Iraq
| | - Fidelia I Uche
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, United Kingdom
| | - Hamza Hameed
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, United Kingdom
| | - Haddijatou Mbye
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, United Kingdom
| | - Imran Ullah
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, United Kingdom
| | - Falko Drijfhout
- Chemical Sciences Research Centre, Keele University, Staffordshire ST5 5BG, United Kingdom
| | - Timothy D W Claridge
- Chemical Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Paul Horrocks
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, United Kingdom
| | - Wen-Wu Li
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, United Kingdom.
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13
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Rizk MA, El-Sayed SAES, AbouLaila M, Tuvshintulga B, Yokoyama N, Igarashi I. Large-scale drug screening against Babesia divergens parasite using a fluorescence-based high-throughput screening assay. Vet Parasitol 2016; 227:93-7. [PMID: 27523944 DOI: 10.1016/j.vetpar.2016.07.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/28/2016] [Accepted: 07/29/2016] [Indexed: 10/21/2022]
Abstract
The validation of a fluorescence-based high-throughput screening (HTS) assay for determining the efficacies of large chemical libraries against Babesia divergens (bovine strain) in in vitro cultures was evaluated in this study. Hematocrits (HCTs) of 2.5%, 5%, and 10% were used for the in vitro culture at 1% parasitemia without daily replacement of the medium. Linearity and HTS assay results revealed that the best HCTs were 5% and 10%. The obtained IC50 values of diminazene aceturate, either by fluorescence-based HTS assay with and without daily replacement of medium or by fluorescence- and microscopy-based methods, did not differ significantly at 5% HCT. Actinonin and chloroquine diphosphate were the most effective drugs against the in vitro growth of B. divergens, followed by pyronaridine tetraphosphate- and luteolin-treated cultures. On contrary, tetracycline hydrochloride and (-)-epigallocatechin-3-gallate from green tea exhibited poor activity as compared with diminazene aceturate (positive control drug). The data indicated that 5% HCT without daily replacement of the culture medium mixed with bovine serum in vitro using a fluorescence-based HTS assay creates the best conditions for large-scale drug screening against B. divergens that infect cattle.
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Affiliation(s)
- Mohamed Abdo Rizk
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, Japan; Department of Internal Medicine and Infectious Diseases, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Shimaa Abd El-Salam El-Sayed
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, Japan; Department of Biochemistry and Chemistry of Nutrition, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Mahmoud AbouLaila
- Department of Parasitology, Faculty of Veterinary Medicine, University of Sadat City, Sadat City 32511, Minoufiya, Egypt
| | - Bumduuren Tuvshintulga
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, Japan; Laboratory of Molecular Genetics, Institute of Veterinary Medicine, Ulaanbaatar, Mongolia
| | - Naoaki Yokoyama
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, Japan
| | - Ikuo Igarashi
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, Japan.
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14
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Hovlid ML, Winzeler EA. Phenotypic Screens in Antimalarial Drug Discovery. Trends Parasitol 2016; 32:697-707. [PMID: 27247245 DOI: 10.1016/j.pt.2016.04.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 04/21/2016] [Indexed: 12/11/2022]
Abstract
Phenotypic high-throughput screens are a valuable tool for identifying new chemical compounds with antimalarial activity. Traditionally, these screens have focused solely on the symptomatic asexual blood stage of the parasite life cycle; however, to discover new medicines for malaria treatment and prevention, robust screening technologies against other parasite life-cycle stages are required. This review highlights recent advances and progress toward phenotypic screening methodologies over the past several years, with a focus on exoerythrocytic stage screens.
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Affiliation(s)
- Marisa L Hovlid
- School of Medicine, Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California, San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Elizabeth A Winzeler
- School of Medicine, Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California, San Diego (UCSD), 9500 Gilman Drive, La Jolla, CA 92093, USA.
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Mokgethi-Morule T, N'Da DD. Cell based assays for anti-Plasmodium activity evaluation. Eur J Pharm Sci 2016; 84:26-36. [PMID: 26776968 DOI: 10.1016/j.ejps.2016.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 12/28/2015] [Accepted: 01/02/2016] [Indexed: 10/22/2022]
Abstract
Malaria remains one of the most common and deadly infectious diseases worldwide. The severity of this global public health challenge is reflected by the approximately 198 million people, who were reportedly infected in 2013 and by the more than 584,000 related deaths in that same year. The rising emergence of drug resistance towards the once effective artemisinin combination therapies (ACTs) has become a serious concern and warrants more robust drug development strategies, with the objective of eradicating malaria infections. The intricate biology and life cycle of Plasmodium parasites complicate the understanding of the disease in such a way that would enhance the development of more effective chemotherapies that would achieve radical clinical cure and that would prevent disease relapse. Phenotypic cell based assays have for long been a valuable approach and involve the screening and analysis of diverse compounds with regards to their activities towards whole Plasmodium parasites in vitro. To achieve the Millennium Development Goal (MDG) of malaria eradication by 2020, new generation drugs that are active against all parasite stages (erythrocytic (blood), exo-erythrocytic (liver stages and gametocytes)) are needed. Significant advances are being made in assay development to overcome some of the practical challenges of assessing drug efficacy, particularly in the liver and transmission stage Plasmodium models. This review discusses primary screening models and the fundamental progress being made in whole cell based efficacy screens of anti-malarial activity. Ongoing challenges and some opportunities for improvements in assay development that would assist in the discovery of effective, safe and affordable drugs for malaria treatments are also discussed.
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Affiliation(s)
- Thabang Mokgethi-Morule
- Drug Design, Centre of Excellence for Pharmaceutical Sciences (PHARMACEN), North-West University, Potchefstroom 2520, South Africa
| | - David D N'Da
- Drug Design, Centre of Excellence for Pharmaceutical Sciences (PHARMACEN), North-West University, Potchefstroom 2520, South Africa.
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16
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Merrick CJ. Transfection with thymidine kinase permits bromodeoxyuridine labelling of DNA replication in the human malaria parasite Plasmodium falciparum. Malar J 2015; 14:490. [PMID: 26630917 PMCID: PMC4668656 DOI: 10.1186/s12936-015-1014-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/24/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Plasmodium falciparum, the causative agent of severe human malaria, is an early-diverging protozoan whose lifecycle has many unusual features, including its modes of replication. Research on the Plasmodium cell cycle, which occurs primarily via schizogony instead of canonical binary fission, has been hampered by a lack of tools and markers that can be transferred from cell cycle studies in model organisms. A common tool used to study DNA replication and the cell cycle in human cells is the labelling of newly-replicated DNA with the modified nucleotide bromodeoxyuridine (BrdU), followed by immunofluorescent detection. Plasmodium parasites, however, do not incorporate BrdU because they rely only on de novo synthesis of pyrimidines and do not salvage thymidine analogues like BrdU for conversion into nucleotides. METHODS Analysis of biochemical pathways in Plasmodium indicated that the absence of the enzyme thymidine kinase (TK) may be the only impediment to BrdU incorporation in this organism. A TK gene from Herpes simplex was, therefore, introduced into the Plasmodium falciparum 3D7 strain and the effect on BrdU labelling was assessed by enzyme-linked immunosorbent assay and immunofluorescence microscopy. RESULTS Introduction of a TK gene produces parasites that can indeed incorporate BrdU. This forms a sensitive indicator of DNA replication, which can be detected by both quantitative and qualitative assays on either a population level or a single-cell level. Plasmodium falciparum, when expressing TK, becomes unusually sensitive to BrdU toxicity. CONCLUSIONS BrdU labelling represents a significant new tool for investigating DNA replication and the cell cycle in Plasmodium.
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Affiliation(s)
- Catherine J Merrick
- Centre for Applied Entomology and Parasitology, Faculty of Natural Sciences, Keele University, Keele, Staffordshire, ST55BG, UK.
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17
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Rijpma SR, van der Velden M, González-Pons M, Annoura T, van Schaijk BCL, van Gemert GJ, van den Heuvel JJMW, Ramesar J, Chevalley-Maurel S, Ploemen IH, Khan SM, Franetich JF, Mazier D, de Wilt JHW, Serrano AE, Russel FGM, Janse CJ, Sauerwein RW, Koenderink JB, Franke-Fayard BM. Multidrug ATP-binding cassette transporters are essential for hepatic development of Plasmodium sporozoites. Cell Microbiol 2015; 18:369-83. [PMID: 26332724 DOI: 10.1111/cmi.12517] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 08/11/2015] [Accepted: 08/24/2015] [Indexed: 12/23/2022]
Abstract
Multidrug resistance-associated proteins (MRPs) belong to the C-family of ATP-binding cassette (ABC) transport proteins and are known to transport a variety of physiologically important compounds and to be involved in the extrusion of pharmaceuticals. Rodent malaria parasites encode a single ABC transporter subfamily C protein, whereas human parasites encode two: MRP1 and MRP2. Although associated with drug resistance, their biological function and substrates remain unknown. To elucidate the role of MRP throughout the parasite life cycle, Plasmodium berghei and Plasmodium falciparum mutants lacking MRP expression were generated. P. berghei mutants lacking expression of the single MRP as well as P. falciparum mutants lacking MRP1, MRP2 or both proteins have similar blood stage growth kinetics and drug-sensitivity profiles as wild type parasites. We show that MRP1-deficient parasites readily invade primary human hepatocytes and develop into mature liver stages. In contrast, both P. falciparum MRP2-deficient parasites and P. berghei mutants lacking MRP protein expression abort in mid to late liver stage development, failing to produce mature liver stages. The combined P. berghei and P. falciparum data are the first demonstration of a critical role of an ABC transporter during Plasmodium liver stage development.
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Affiliation(s)
- Sanna R Rijpma
- Department of Pharmacology and Toxicology, Radboud University Medical Centre, Geert-Grooteplein 28, 6525 GA, Nijmegen, The Netherlands
| | - Maarten van der Velden
- Department of Pharmacology and Toxicology, Radboud University Medical Centre, Geert-Grooteplein 28, 6525 GA, Nijmegen, The Netherlands
| | - Maria González-Pons
- Department of Microbiology and Medical Zoology, University of Puerto Rico, School of Medicine, PR 00936-5067, San Juan, Puerto Rico, USA
| | - Takeshi Annoura
- Department of Tropical Medicine, The Jikei University School of Medicine, Post code 105-8461, Nishi-shinbashi 3-25-8, Minato-ku, Tokyo, Japan
| | - Ben C L van Schaijk
- Department of Medical Microbiology, Radboud University Medical Centre, Geert-Grooteplein 28, 6525 GA, Nijmegen, The Netherlands
| | - Geert-Jan van Gemert
- Department of Medical Microbiology, Radboud University Medical Centre, Geert-Grooteplein 28, 6525 GA, Nijmegen, The Netherlands
| | - Jeroen J M W van den Heuvel
- Department of Pharmacology and Toxicology, Radboud University Medical Centre, Geert-Grooteplein 28, 6525 GA, Nijmegen, The Netherlands
| | - Jai Ramesar
- Department of Parasitology, Center of Infectious Diseases, Leiden Malaria Research Group, Leiden, The Netherlands
| | - Severine Chevalley-Maurel
- Department of Parasitology, Center of Infectious Diseases, Leiden Malaria Research Group, Leiden, The Netherlands
| | - Ivo H Ploemen
- Department of Medical Microbiology, Radboud University Medical Centre, Geert-Grooteplein 28, 6525 GA, Nijmegen, The Netherlands
| | - Shahid M Khan
- Department of Tropical Medicine, The Jikei University School of Medicine, Post code 105-8461, Nishi-shinbashi 3-25-8, Minato-ku, Tokyo, Japan
| | - Jean-Francois Franetich
- AP-HP, Groupe hospitalier Pitié-Salpêtrière, Service Parasitologie-Mycologie, 47-83 Boulevard de l'Hôpital, 75651, Paris, France
| | - Dominique Mazier
- AP-HP, Groupe hospitalier Pitié-Salpêtrière, Service Parasitologie-Mycologie, 47-83 Boulevard de l'Hôpital, 75651, Paris, France.,CIMI-Paris (UPMC UMRS CR7 - Inserm U1135 - CNRS ERL 8255), Paris, France
| | - Johannes H W de Wilt
- Department of Surgery, Radboud University Medical Centre, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Adelfa E Serrano
- Department of Microbiology and Medical Zoology, University of Puerto Rico, School of Medicine, PR 00936-5067, San Juan, Puerto Rico, USA
| | - Frans G M Russel
- Department of Pharmacology and Toxicology, Radboud University Medical Centre, Geert-Grooteplein 28, 6525 GA, Nijmegen, The Netherlands
| | - Chris J Janse
- Department of Parasitology, Center of Infectious Diseases, Leiden Malaria Research Group, Leiden, The Netherlands
| | - Robert W Sauerwein
- Department of Medical Microbiology, Radboud University Medical Centre, Geert-Grooteplein 28, 6525 GA, Nijmegen, The Netherlands
| | - Jan B Koenderink
- Department of Pharmacology and Toxicology, Radboud University Medical Centre, Geert-Grooteplein 28, 6525 GA, Nijmegen, The Netherlands
| | - Blandine M Franke-Fayard
- Department of Parasitology, Center of Infectious Diseases, Leiden Malaria Research Group, Leiden, The Netherlands
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18
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Siciliano G, Alano P. Enlightening the malaria parasite life cycle: bioluminescent Plasmodium in fundamental and applied research. Front Microbiol 2015; 6:391. [PMID: 26029172 PMCID: PMC4426725 DOI: 10.3389/fmicb.2015.00391] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/16/2015] [Indexed: 12/31/2022] Open
Abstract
The unicellular protozoan parasites of the genus Plasmodium impose on human health worldwide the enormous burden of malaria. The possibility to genetically modify several species of malaria parasites represented a major advance in the possibility to elucidate their biology and is now turning laboratory lines of transgenic Plasmodium into precious weapons to fight malaria. Amongst the various genetically modified plasmodia, transgenic parasite lines expressing bioluminescent reporters have been essential to unveil mechanisms of parasite gene expression and to develop in vivo imaging approaches in mouse malaria models. Mainly the human malaria parasite Plasmodium falciparum and the rodent parasite P. berghei have been engineered to express bioluminescent reporters in almost all the developmental stages of the parasite along its complex life cycle between the insect and the vertebrate hosts. Plasmodium lines expressing conventional and improved luciferase reporters are now gaining a central role to develop cell based assays in the much needed search of new antimalarial drugs and to open innovative approaches for both fundamental and applied research in malaria.
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Affiliation(s)
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di SanitàRome, Italy
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19
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Optimization of a Fluorescence-Based Assay for Large-Scale Drug Screening against Babesia and Theileria Parasites. PLoS One 2015; 10:e0125276. [PMID: 25915529 PMCID: PMC4411034 DOI: 10.1371/journal.pone.0125276] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 03/23/2015] [Indexed: 11/19/2022] Open
Abstract
A rapid and accurate assay for evaluating antibabesial drugs on a large scale is required for the discovery of novel chemotherapeutic agents against Babesia parasites. In the current study, we evaluated the usefulness of a fluorescence-based assay for determining the efficacies of antibabesial compounds against bovine and equine hemoparasites in in vitro cultures. Three different hematocrits (HCTs; 2.5%, 5%, and 10%) were used without daily replacement of the medium. The results of a high-throughput screening assay revealed that the best HCT was 2.5% for bovine Babesia parasites and 5% for equine Babesia and Theileria parasites. The IC50 values of diminazene aceturate obtained by fluorescence and microscopy did not differ significantly. Likewise, the IC50 values of luteolin, pyronaridine tetraphosphate, nimbolide, gedunin, and enoxacin did not differ between the two methods. In conclusion, our fluorescence-based assay uses low HCT and does not require daily replacement of culture medium, making it highly suitable for in vitro large-scale drug screening against Babesia and Theileria parasites that infect cattle and horses.
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20
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De Niz M, Helm S, Horstmann S, Annoura T, del Portillo HA, Khan SM, Heussler VT. In vivo and in vitro characterization of a Plasmodium liver stage-specific promoter. PLoS One 2015; 10:e0123473. [PMID: 25874388 PMCID: PMC4398466 DOI: 10.1371/journal.pone.0123473] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 03/03/2015] [Indexed: 12/28/2022] Open
Abstract
Little is known about stage-specific gene regulation in Plasmodium parasites, in particular the liver stage of development. We have previously described in the Plasmodium berghei rodent model, a liver stage-specific (lisp2) gene promoter region, in vitro. Using a dual luminescence system, we now confirm the stage specificity of this promoter region also in vivo. Furthermore, by substitution and deletion analyses we have extended our in vitro characterization of important elements within the promoter region. Importantly, the dual luminescence system allows analyzing promoter constructs avoiding mouse-consuming cloning procedures of transgenic parasites. This makes extensive mutation and deletion studies a reasonable approach also in the malaria mouse model. Stage-specific expression constructs and parasite lines are extremely valuable tools for research on Plasmodium liver stage biology. Such reporter lines offer a promising opportunity for assessment of liver stage drugs, characterization of genetically attenuated parasites and liver stage-specific vaccines both in vivo and in vitro, and may be key for the generation of inducible systems.
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Affiliation(s)
- Mariana De Niz
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- * E-mail:
| | - Susanne Helm
- Molecular Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Sebastian Horstmann
- Molecular Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Takeshi Annoura
- Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
- Department of Parasitology, National Institute of Infectious Diseases (NIID), Tokyo, Japan
| | - Hernando A. del Portillo
- Barcelona Centre for International Health Research (CRESIB), Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | - Shahid M. Khan
- Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
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21
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Sherlach KS, Roepe PD. Determination of the cytostatic and cytocidal activities of antimalarial compounds and their combination interactions. ACTA ACUST UNITED AC 2014; 6:237-248. [PMID: 25445179 DOI: 10.1002/9780470559277.ch140125] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Determining the antiplasmodial activity of candidate antimalarial drugs in vitro identifies new therapies for drug-resistant malaria. Importantly though, activity can be either growth-inhibitory (cytostatic) or parasite-kill (cytocidal), or both. The simple methods described here can allow for distinction between these activities, as well as definition of drug interactions between two or more compounds. The latter is important in the definition of novel drug combination therapy for malaria. These methods involve live malarial parasite red blood cell culture, routine pharmacology, high-throughput detection of parasite DNA with fluorescent reporters, and routine mathematical analysis of dose-response curves. The techniques and approaches are accessible to most laboratories and require minimal special equipment beyond a fluorescent plate reader and tissue culture facilities.
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Affiliation(s)
- Katy S Sherlach
- Department of Chemistry and Department of Biochemistry and Cellular and Molecular Biology, Georgetown University, Washington, D.C
| | - Paul D Roepe
- Department of Chemistry and Department of Biochemistry and Cellular and Molecular Biology, Georgetown University, Washington, D.C
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22
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Plasmodium falciparum transfected with ultra bright NanoLuc luciferase offers high sensitivity detection for the screening of growth and cellular trafficking inhibitors. PLoS One 2014; 9:e112571. [PMID: 25392998 PMCID: PMC4231029 DOI: 10.1371/journal.pone.0112571] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 10/08/2014] [Indexed: 11/19/2022] Open
Abstract
Drug discovery is a key part of malaria control and eradication strategies, and could benefit from sensitive and affordable assays to quantify parasite growth and to help identify the targets of potential anti-malarial compounds. Bioluminescence, achieved through expression of exogenous luciferases, is a powerful tool that has been applied in studies of several aspects of parasite biology and high throughput growth assays. We have expressed the new reporter NanoLuc (Nluc) luciferase in Plasmodium falciparum and showed it is at least 100 times brighter than the commonly used firefly luciferase. Nluc brightness was explored as a means to achieve a growth assay with higher sensitivity and lower cost. In addition we attempted to develop other screening assays that may help interrogate libraries of inhibitory compounds for their mechanism of action. To this end parasites were engineered to express Nluc in the cytoplasm, the parasitophorous vacuole that surrounds the intraerythrocytic parasite or exported to the red blood cell cytosol. As proof-of-concept, these parasites were used to develop functional screening assays for quantifying the effects of Brefeldin A, an inhibitor of protein secretion, and Furosemide, an inhibitor of new permeation pathways used by parasites to acquire plasma nutrients.
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23
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Evaluation of a fluorescence-based method for antibabesial drug screening. Antimicrob Agents Chemother 2014; 58:4713-7. [PMID: 24914124 DOI: 10.1128/aac.00022-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In vitro evaluation of chemotherapeutic agents against Babesia and Theileria parasites has become routine, and the effectiveness of these chemicals is usually determined by comparing the parasitemia dynamics of untreated and treated parasites. Although microscopy is widely used to calculate parasitemia, several disadvantages are associated with this technique. The present study evaluated a fluorescence-based method using SYBR green I stain (SG I) to screen antibabesial agents in in vitro cultures of Babesia bovis. The linearity between relative fluorescence units (RFU) and parasitemia was found to be well correlated with a 0.9944 goodness-of-fit (r(2)) value. Subsequently, 50% inhibitory concentration (IC50) values were calculated for 3 antiprotozoan agents, diminazene aceturate, nimbolide, and gedunin, by this method. For diminazene aceturate and nimbolide, the IC(50)s determined by the fluorescence-based method (408 nM and 8.13 μM, respectively) and microscopy (400.3 nM and 9.4 μM, respectively) were in agreement. Furthermore, the IC50 of gedunin determined by the fluorescence-based method (19 μM) was similar to the recently described microscopy-based value (21.7 μM) for B. bovis. Additionally, the Z' factor (0.80 to 0.90), signal-to-noise (S/N) ratio (44.15 to 87.64), coefficient of variation at the maximum signal (%CVmax) (0.50 to 2.85), and coefficient of variation at the minimum signal (%CVmin) (1.23 to 2.21) calculated for the fluorescence method using diminazene aceturate were comparable to those previously determined in malaria research for this assay. These findings suggest that the fluorescence-based method might be useful for antibabesial drug screening and may have potential to be developed into a high-throughput screening (HTS) assay.
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24
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Roepe PD. To kill or not to kill, that is the question: cytocidal antimalarial drug resistance. Trends Parasitol 2014; 30:130-5. [PMID: 24530127 DOI: 10.1016/j.pt.2014.01.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 01/07/2014] [Accepted: 01/09/2014] [Indexed: 02/03/2023]
Abstract
Elucidating mechanisms of antimalarial drug resistance accelerates development of improved diagnostics and the design of new, effective malaria therapy. Recently, several studies have emphasized that chloroquine (CQ) resistance (CQR) can be quantified in two very distinct ways, depending on whether sensitivity to the growth inhibitory effects or parasite-kill effects of the drug are being measured. It is now clear that these cytostatic and cytocidal CQR phenotypes are not equivalent, and recent genetic, cell biological, and biophysical evidence suggests how the molecular mechanisms may overlap. These conclusions have important implications for elucidating other drug resistance phenomena and emphasize new concepts that are essential for the development of new drug therapy.
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Affiliation(s)
- Paul D Roepe
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington DC 20057, USA; Department of Biochemistry and Cellular and Molecular Biology, Georgetown University, 37th and O Streets NW, Washington DC 20057, USA.
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