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Hilko DH, Fisher GM, Addison RS, Andrews KT, Poulsen SA. Thymidine Kinase-Independent Click Chemistry DNADetect Probes for DNA Proliferation Assessment in Malaria Parasites. ACS Chem Biol 2023; 18:2535-2543. [PMID: 38050717 DOI: 10.1021/acschembio.3c00530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
Metabolic chemical probes are small-molecule reagents that utilize naturally occurring biosynthetic enzymes for in situ incorporation into biomolecules of interest. These reagents can be used to label, detect, and track important biological processes within living cells including protein synthesis, protein glycosylation, and nucleic acid proliferation. A limitation of current chemical probes, which have largely focused on mammalian cells, is that they often cannot be applied to other organisms due to metabolic differences. For example, the thymidine derivative 5-ethynyl-2'-deoxyuridine (EdU) is a gold standard metabolic chemical probe for assessing DNA proliferation in mammalian cells; however, it is unsuitable for the study of malaria parasites due to Plasmodium species lacking the thymidine kinase enzyme that is essential for metabolism of EdU. Herein, we report the design and synthesis of new thymidine-based probes that sidestep the requirement for a thymidine kinase enzyme in Plasmodium. Two of these DNADetect probes exhibit robust labeling of replicating asexual intraerythrocytic Plasmodium falciparum parasites, as determined by flow cytometry and fluorescence microscopy using copper-catalyzed azide-alkyne cycloaddition to a fluorescent azide. The DNADetect chemical probes are synthetically accessible and thus can be made widely available to researchers as tools to further understand the biology of different Plasmodium species, including laboratory lines and clinical isolates.
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Affiliation(s)
- David H Hilko
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland 4111, Australia
| | - Gillian M Fisher
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland 4111, Australia
| | - Russell S Addison
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland 4111, Australia
| | - Katherine T Andrews
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland 4111, Australia
| | - Sally-Ann Poulsen
- Griffith Institute for Drug Discovery, Griffith University, Nathan, Brisbane, Queensland 4111, Australia
- School of Environment and Science, Griffith University, Nathan, Brisbane, Queensland 4111, Australia
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Rosenthal MR, Ng CL. High-content imaging as a tool to quantify and characterize malaria parasites. CELL REPORTS METHODS 2023; 3:100516. [PMID: 37533635 PMCID: PMC10391350 DOI: 10.1016/j.crmeth.2023.100516] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 01/18/2023] [Accepted: 06/02/2023] [Indexed: 08/04/2023]
Abstract
In 2021, Plasmodium falciparum was responsible for 619,000 reported malaria-related deaths. Resistance has been detected to every clinically used antimalarial, urging the development of novel antimalarials with uncompromised mechanisms of actions. High-content imaging allows researchers to collect and quantify numerous phenotypic properties at the single-cell level, and machine learning-based approaches enable automated classification and clustering of cell populations. By combining these technologies, we developed a method capable of robustly differentiating and quantifying P. falciparum asexual blood stages. These phenotypic properties also allow for the quantification of changes in parasite morphology. Here, we demonstrate that our analysis can be used to quantify schizont nuclei, a phenotype that previously had to be enumerated manually. By monitoring stage progression and quantifying parasite phenotypes, our method can discern stage specificity of new compounds, thus providing insight into the compound's mode of action.
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Affiliation(s)
- Melissa R. Rosenthal
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Caroline L. Ng
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Global Center for Health Security, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Biology, University of Omaha, Omaha, NE 68182, USA
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de Koning-Ward TF, Boddey JA, Fowkes FJ. Editorial: Molecular Approaches to Malaria 2020. Int J Parasitol 2022; 52:705-706. [DOI: 10.1016/j.ijpara.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Vantaux A, Péneau J, Cooper CA, Kyle DE, Witkowski B, Maher SP. Liver-stage fate determination in Plasmodium vivax parasites: Characterization of schizont growth and hypnozoite fating from patient isolates. Front Microbiol 2022; 13:976606. [PMID: 36212849 PMCID: PMC9539820 DOI: 10.3389/fmicb.2022.976606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 08/11/2022] [Indexed: 11/13/2022] Open
Abstract
Plasmodium vivax, one species of parasite causing human malaria, forms a dormant liver stage, termed the hypnozoite, which activate weeks, months or years after the primary infection, causing relapse episodes. Relapses significantly contribute to the vivax malaria burden and are only killed with drugs of the 8-aminoquinoline class, which are contraindicated in many vulnerable populations. Development of new therapies targeting hypnozoites is hindered, in part, by the lack of robust methods to continuously culture and characterize this parasite. As a result, the determinants of relapse periodicity and the molecular processes that drive hypnozoite formation, persistence, and activation are largely unknown. While previous reports have described vastly different liver-stage growth metrics attributable to which hepatocyte donor lot is used to initiate culture, a comprehensive assessment of how different P. vivax patient isolates behave in the same lots at the same time is logistically challenging. Using our primary human hepatocyte-based P. vivax liver-stage culture platform, we aimed to simultaneously test the effects of how hepatocyte donor lot and P. vivax patient isolate influence the fate of sporozoites and growth of liver schizonts. We found that, while environmental factors such as hepatocyte donor lot can modulate hypnozoite formation rate, the P. vivax case is also an important determinant of the proportion of hypnozoites observed in culture. In addition, we found schizont growth to be mostly influenced by hepatocyte donor lot. These results suggest that, while host hepatocytes harbor characteristics making them more- or less-supportive of a quiescent versus growing intracellular parasite, sporozoite fating toward hypnozoites is isolate-specific. Future studies involving these host–parasite interactions, including characterization of individual P. vivax strains, should consider the impact of culture conditions on hypnozoite formation, in order to better understand this important part of the parasite’s lifecycle.
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Affiliation(s)
- Amélie Vantaux
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
- *Correspondence: Amélie Vantaux,
| | - Julie Péneau
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Caitlin A. Cooper
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
| | - Dennis E. Kyle
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
| | - Benoit Witkowski
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Steven P. Maher
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
- Steven P. Maher,
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