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Kalamuddin M, Shakri AR, Wang C, Min H, Li X, Cui L, Miao J. MYST regulates DNA repair and forms a NuA4-like complex in the malaria parasite Plasmodium falciparum. mSphere 2024; 9:e0014024. [PMID: 38564734 PMCID: PMC11036802 DOI: 10.1128/msphere.00140-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 03/13/2024] [Indexed: 04/04/2024] Open
Abstract
Histone lysine acetyltransferase MYST-associated NuA4 complex is conserved from yeast to humans and plays key roles in cell cycle regulation, gene transcription, and DNA replication/repair. Here, we identified a Plasmodium falciparum MYST-associated complex, PfNuA4, which contains 11 of the 13 conserved NuA4 subunits. Reciprocal pulldowns using PfEAF2, a shared component between the NuA4 and SWR1 complexes, not only confirmed the PfNuA4 complex but also identified the PfSWR1 complex, a histone remodeling complex, although their identities are low compared to the homologs in yeast or humans. Notably, both H2A.Z/H2B.Z were associated with the PfSWR1 complex, indicating that this complex is involved in the deposition of H2A.Z/H2B.Z, the variant histone pair that is enriched in the activated promoters. Overexpression of PfMYST resulted in earlier expression of genes involved in cell cycle regulation, DNA replication, and merozoite invasion, and upregulation of the genes related to antigenic variation and DNA repair. Consistently, PfMYST overexpression led to high basal phosphorylated PfH2A (γ-PfH2A), the mark of DNA double-strand breaks, and conferred protection against genotoxic agent methyl methanesulfonate (MMS), X-rays, and artemisinin, the first-line antimalarial drug. In contrast, the knockdown of PfMYST caused a delayed parasite recovery upon MMS treatment. MMS induced the gradual disappearance of PfMYST in the cytoplasm and concomitant accumulation of PfMYST in the nucleus, suggesting cytoplasm-nucleus shuttling of PfMYST. Meanwhile, PfMYST colocalized with the γ-PfH2A, indicating PfMYST was recruited to the DNA damage sites. Collectively, PfMYST plays critical roles in cell cycle regulation, gene transcription, and DNA replication/DNA repair in this low-branching parasitic protist.IMPORTANCEUnderstanding gene regulation and DNA repair in malaria parasites is critical for identifying targets for antimalarials. This study found PfNuA4, a PfMYST-associated, histone modifier complex, and PfSWR1, a chromatin remodeling complex in malaria parasite Plasmodium falciparum. These complexes are divergent due to the low identities compared to their homologs from yeast and humans. Furthermore, overexpression of PfMYST resulted in substantial transcriptomic changes, indicating that PfMYST is involved in regulating the cell cycle, antigenic variation, and DNA replication/repair. Consistently, PfMYST was found to protect against DNA damage caused by the genotoxic agent methyl methanesulfonate, X-rays, and artemisinin, the first-line antimalarial drug. Additionally, DNA damage led to the relocation of cytoplasmic PfMYST to the nucleus and colocalization of PfMYST with γ-PfH2A, the mark of DNA damage. In summary, this study demonstrated that the PfMYST complex has critical functions in regulating cell cycle, antigenic variation, and DNA replication/DNA repair in P. falciparum.
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Affiliation(s)
- Mohammad Kalamuddin
- Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Florida, USA
| | - Ahmad Rushdi Shakri
- Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Florida, USA
| | - Chengqi Wang
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Hui Min
- Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Florida, USA
| | - Xiaolian Li
- Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Florida, USA
| | - Liwang Cui
- Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Florida, USA
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Jun Miao
- Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Florida, USA
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
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Lucky AB, Wang C, Li X, Liang X, Muneer A, Miao J. Transforming the CRISPR/dCas9-based gene regulation technique into a forward screening tool in Plasmodium falciparum. iScience 2024; 27:109602. [PMID: 38617559 PMCID: PMC11015506 DOI: 10.1016/j.isci.2024.109602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 02/11/2024] [Accepted: 03/25/2024] [Indexed: 04/16/2024] Open
Abstract
It is a significant challenge to assess the functions of many uncharacterized genes in human malaria parasites. Here, we present a genetic screening tool to assess the contribution of essential genes from Plasmodium falciparum by the conditional CRISPR-/deadCas9-based interference and activation (i/a) systems. We screened both CRISPRi and CRISPRa sets, consisting of nine parasite lines per set targeting nine genes via their respective gRNAs. By conducting amplicon sequencing of gRNA loci, we identified the contribution of each targeted gene to parasite fitness upon drug (artemisinin, chloroquine) and stress (starvation, heat shock) treatment. The screening was highly reproducible, and the screening libraries were easily generated by transfection of mixed plasmids expressing different gRNAs. We demonstrated that this screening is straightforward, robust, and can provide a fast and efficient tool to study essential genes that have long presented a bottleneck in assessing their functions using existing genetic tools.
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Affiliation(s)
- Amuza Byaruhanga Lucky
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
| | - Chengqi Wang
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
| | - Xiaolian Li
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
| | - Xiaoying Liang
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
| | - Azhar Muneer
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
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Kassimu KR, Ali AM, Omolo JJ, Mdemu A, Machumi F, Ngasala B. The effect of an anti-malarial herbal remedy, Maytenus senegalensis, on electrocardiograms of healthy Tanzanian volunteers. Malar J 2024; 23:103. [PMID: 38609987 PMCID: PMC11015626 DOI: 10.1186/s12936-024-04935-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 04/05/2024] [Indexed: 04/14/2024] Open
Abstract
BACKGROUND The emergence of resistance to artemisinin-based combination therapy necessitates the search for new, more potent antiplasmodial compounds, including herbal remedies. The whole extract of Maytenus senegalensis has been scientifically investigated for potential biological activities both in vitro and in vivo, demonstrating strong antimalarial activity. However, there is a lack of data on the electrocardiographic effects of M. senegalensis in humans, which is a crucial aspect in the investigation of malaria treatment. Assessing the electrocardiographic effects of M. senegalensis is essential, as many anti-malarial drugs can inadvertently prolong the QT interval on electrocardiograms. Therefore, the study's objective was to evaluate the electrocardiographic effects of M. senegalensis in healthy adult volunteers. METHODS This study is a secondary analysis of an open-label single-arm dose escalation. Twelve healthy eligible Tanzanian males, aged 18 to 45, were enrolled in four study dose groups. A single 12-lead electrocardiogram (ECG) was performed at baseline and on days 3, 7, 14, 28, and 56. RESULTS No QTcF adverse events occurred with any drug dose. Only one volunteer who received the highest dose (800 mg) of M. senegalensis experienced a moderate transient change (△QTcF > 30 ms; specifically, the value was 37 ms) from baseline on day 28. There was no difference in maximum QTcF and maximum △QTcF between volunteers in all four study dose groups. CONCLUSIONS A four-day regimen of 800 mg every 8 h of M. senegalensis did not impact the electrocardiographic parameters in healthy volunteers. This study suggests that M. senegalensis could be a valuable addition to malaria treatment, providing a safer alternative and potentially aiding in the battle against artemisinin-resistant malaria. The results of this study support both the traditional use and the modern therapeutic potential of M. senegalensis. They also set the stage for future research involving larger and more diverse populations to explore the safety profile of M. senegalensis in different demographic groups. This is especially important considering the potential use of M. senegalensis as a therapeutic agent and its widespread utilization as traditional medicine. Trial registration ClinicalTrials.gov, NCT04944966. Registered 30 June 2021-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04944966?term=kamaka&draw=2&rank=1.
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Affiliation(s)
- Kamaka R Kassimu
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, 74, Bagamoyo, Tanzania.
- Department of Parasitology, Muhimbili University of Health and Allied Sciences, 65001, Dar es Salaam, Tanzania.
| | - Ali M Ali
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, 74, Bagamoyo, Tanzania
| | - Justin J Omolo
- Traditional Medicine Research and Development Center, National Institute for Medical Research, 9653, Dar es Salaam, Tanzania
| | - Abel Mdemu
- Traditional Medicine Research and Development Center, National Institute for Medical Research, 9653, Dar es Salaam, Tanzania
| | - Francis Machumi
- Institute of Traditional Medicine, Muhimbili University of Health and Allied Sciences, 65001, Dar es Salaam, Tanzania
| | - Billy Ngasala
- Department of Parasitology, Muhimbili University of Health and Allied Sciences, 65001, Dar es Salaam, Tanzania
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Lucky AB, Wang C, Shakri AR, Kalamuddin M, Chim-Ong A, Li X, Miao J. Plasmodium falciparum GCN5 plays a key role in regulating artemisinin resistance-related stress responses. Antimicrob Agents Chemother 2023; 67:e0057723. [PMID: 37702516 PMCID: PMC10583690 DOI: 10.1128/aac.00577-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/24/2023] [Indexed: 09/14/2023] Open
Abstract
Plasmodium falciparum causes the most severe malaria and is exposed to various environmental and physiological stresses in the human host. Given that GCN5 plays a critical role in regulating stress responses in model organisms, we aimed to elucidate PfGCN5's function in stress responses in P. falciparum. The protein level of PfGCN5 was substantially induced under three stress conditions [heat shock, low glucose starvation, and dihydroartemisinin, the active metabolite of artemisinin (ART)]. With a TetR-DOZI conditional knockdown (KD) system, we successfully down-regulated PfGCN5 to ~50% and found that KD parasites became more sensitive to all three stress conditions. Transcriptomic analysis via RNA-seq identified ~1,000 up- and down-regulated genes in the wild-type (WT) and KD parasites under these stress conditions. Importantly, DHA induced transcriptional alteration of many genes involved in many aspects of stress responses, which were heavily shared among the altered genes under heat shock and low glucose conditions, including ART-resistance-related genes such as K13 and coronin. Based on the expression pattern between WT and KD parasites under three stress conditions, ~300-400 genes were identified to be involved in PfGCN5-dependent, general, and stress-condition-specific responses with high levels of overlaps among three stress conditions. Notably, using ring-stage survival assay, we found that KD or inhibition of PfGCN5 could sensitize the ART-resistant parasites to the DHA treatment. All these indicate that PfGCN5 is pivotal in regulating general and ART-resistance-related stress responses in malaria parasites, implicating PfGCN5 as a potential target for malaria intervention.
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Affiliation(s)
- Amuza Byaruhanga Lucky
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Chengqi Wang
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Ahmad Rushdi Shakri
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Mohammad Kalamuddin
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Anongruk Chim-Ong
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Xiaolian Li
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
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Barati S, Haghi AM, Nateghpour M, Zamani Z, Khodaveisi S, Etemadi S. Induction of Artesunate Resistance in Plasmodium falciparum 3D7 Strain Using Intermittent Exposure Method and Comparing P.fk13 Sequence between Susceptible and Resistant Strains. IRANIAN JOURNAL OF PARASITOLOGY 2023; 18:445-455. [PMID: 38169593 PMCID: PMC10758072 DOI: 10.18502/ijpa.v18i4.14244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 07/18/2023] [Indexed: 01/05/2024]
Abstract
Background Resistance to artemisinin has threatened major achievements in malaria control, more investigations is needed about resistant strains and related genes. We aimed to induce resistance to artesunate in the Plasmodium falciparum 3D7 strain using intermittent exposure method and comparing P.fk13 gene sequence between susceptible and resistance strains. Methods P. falciparum 3D7 strain was cultured according to Trager & Jensen method with some modifications. Serial concentrations between 10-2 mol/l, to 10-7mol/l were prepared, then P. falciparum 3D7 was exposed to each of the dilution to determine IC50 and lethal dose. Sensitivity reduction process was started from the concentration of 10-7mol/l and ended at 10-2mol/l. Exposed parasites were collected after at least 27 days after cultivation in each drug concentration. DNA extraction, PCR and sequencing process were performed to investigate any possible mutations in the P.fk13 gene sequence. Results Effectiveness of 10-2mol/l concentration of artemisinin was found as a lethal dose. IC50 value was equal to 5×10-4 mol/l. The resistant strain was provided in the lab, sequenced and registered in the gene bank as P.f Art -2, (accession number MH796123. 1). Alignment of this registered sample showed no mutation in P.f kelch13 gene in comparison with standard strain submitted in the GenBank. Conclusion Resistance to artesunate in malaria parasite may occur but with no mutation in the P.f kelch13 gene. Therefore, whole genome sequencing should be applied to determine mutations in resistant strains.
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Affiliation(s)
- Sahar Barati
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Afsaneh Motevalli Haghi
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehdi Nateghpour
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Zamani
- Biochemistry Department, Pasteur Institute of Iran, Pasteur Avenue, Tehran, Iran
| | - Sadegh Khodaveisi
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Soudabeh Etemadi
- Department of Medical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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Azmi WA, Rizki AFM, Djuardi Y, Artika IM, Siregar JE. Molecular insights into artemisinin resistance in Plasmodium falciparum: An updated review. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2023:105460. [PMID: 37269964 DOI: 10.1016/j.meegid.2023.105460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/25/2023] [Accepted: 05/27/2023] [Indexed: 06/05/2023]
Abstract
Malaria still poses a major burden on human health around the world, especially in endemic areas. Plasmodium resistance to several antimalarial drugs has been one of the major hindrances in control of malaria. Thus, the World Health Organization recommended artemisinin-based combination therapy (ACT) as a front-line treatment for malaria. The emergence of parasites resistant to artemisinin, along with resistant to ACT partner drugs, has led to ACT treatment failure. The artemisinin resistance is mostly related to the mutations in the propeller domain of the kelch13 (k13) gene that encodes protein Kelch13 (K13). The K13 protein has an important role in parasite reaction to oxidative stress. The most widely spread mutation in K13, with the highest degree of resistance, is a C580Y mutation. Other mutations, which are already identified as markers of artemisinin resistance, are R539T, I543T, and Y493H. The objective of this review is to provide current molecular insights into artemisinin resistance in Plasmodium falciparum. The trending use of artemisinin beyond its antimalarial effect is described. Immediate challenges and future research directions are discussed. Better understanding of the molecular mechanisms underlying artemisinin resistance will accelerate implementation of scientific findings to solve problems with malarial infection.
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Affiliation(s)
- Wihda Aisarul Azmi
- Eijkman Research Center for Molecular Biology, National Research and Innovation Agency, Cibinong, Bogor 16911, Indonesia; Master's Programme in Biomedical Sciences, Faculty of Medicine Universitas Indonesia, Jakarta 10430, Indonesia
| | - Andita Fitri Mutiara Rizki
- Eijkman Research Center for Molecular Biology, National Research and Innovation Agency, Cibinong, Bogor 16911, Indonesia; Master's Programme in Biomedical Sciences, Faculty of Medicine Universitas Indonesia, Jakarta 10430, Indonesia
| | - Yenny Djuardi
- Department of Parasitology, Faculty of Medicine Universitas Indonesia, Jakarta 10430, Indonesia
| | - I Made Artika
- Eijkman Research Center for Molecular Biology, National Research and Innovation Agency, Cibinong, Bogor 16911, Indonesia; Department of Biochemistry, Faculty of Mathematics and Natural Sciences, Bogor Agricultural University, Bogor 16680, Indonesia
| | - Josephine Elizabeth Siregar
- Eijkman Research Center for Molecular Biology, National Research and Innovation Agency, Cibinong, Bogor 16911, Indonesia.
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Anjuwon TM, Ehinmidu JO, Anigo KM, James DB. In Vitro Antimalarial Susceptibility of Plasmodium falciparum and Plasmodium berghei Isolates to Selected Antimalarial Agents, Column Chromatographic Subfractions of Glyphaea brevis Leaves Extract and FTIR and GCMS of SF8. Trop Life Sci Res 2023; 34:279-297. [PMID: 38144385 PMCID: PMC10735266 DOI: 10.21315/tlsr2023.34.2.14] [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: 07/25/2022] [Accepted: 02/02/2023] [Indexed: 12/26/2023] Open
Abstract
Malaria still remains a life-threatening parasitic disease with universal targets set for control and elimination. This study aimed to evaluate the in vitro antimalarial susceptibility of Plasmodium falciparum isolates and Plasmodium berghei to selected antimalarial agents and column chromatographic subfractions of Glyphaea brevis leaves extract and FTIR and GCMS of SF8. Trager and Jensen as well as World Health Organisation (WHO) standardised in vitro micro-test system methods were used to determine susceptibility on the patients' blood samples; Column chromatographic procedure was carried out to obtain 11 pooled fractions; FTIR and GCMS were used to determine functional groups and phytochemicals respectively. In vitro anti-plasmodial activity against P. falciparum clinical isolates had IC50 range of 1.03 μg/mL-7.63 μg/mL while their IC50 against P. berghei ranges from 4.32 μg/mL-7.89 μg/mL. Subfraction 8 (SF8) had the least IC50 of 4.32 μg/mL. The FTIR spectrum showed the presence of isoprenoid, alcohol, phenol, alkane, alkenes, ester, carboxylic acids, aromatics and nitro compounds while GCMS identified dodecanoic acid, methyl ester; carotol; hexadecanoic acid, methyl ester; 9-octadecenoic acid (Z)-, methyl ester (oleic acid); methyl stearate; heptadecanoic acid, 16-methyl-, methyl ester; all with their antimalarial reported activities. In conclusion, G. brevis has a great potential for drug development against malaria parasite since it inhibited schizont growth and possesses phytocompounds with antimalarial report.
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Affiliation(s)
- Tayo Micheal Anjuwon
- Department of Biochemistry, Ahmadu Bello University, P.M.B 1069 Zaria, Kaduna State, Nigeria
| | - Joseph Olorunmola Ehinmidu
- Department of Pharmaceutical Microbiology, Ahmadu Bello University, P.M.B 1069 Zaria, Kaduna State, Nigeria
| | | | - Dorcas Bolanle James
- Department of Biochemistry, Ahmadu Bello University, P.M.B 1069 Zaria, Kaduna State, Nigeria
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Lucky AB, Wang C, Shakri AR, Kalamuddin M, Chim-Ong A, Li X, Miao J. Plasmodium falciparum GCN5 plays a key role in regulating artemisinin resistance-related stress responses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.11.523703. [PMID: 36711954 PMCID: PMC9882135 DOI: 10.1101/2023.01.11.523703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Plasmodium falciparum causes the most severe malaria and is exposed to various environmental and physiological stresses in the human host. Given that GCN5 plays a critical role in regulating stress responses in model organisms, we aimed to elucidate PfGCN5's function in stress responses in P. falciparum . The protein level of PfGCN5 was substantially induced under three stress conditions (heat shock, low glucose starvation, and dihydroartemisinin, the active metabolite of artemisinin (ART)). With a TetR-DOZI conditional knockdown (KD) system, we successfully down-regulated PfGCN5 to ∼50% and found that KD parasites became more sensitive to all three stress conditions. Transcriptomic analysis via RNA-seq identified ∼1,000 up-and down-regulated genes in the wildtype (WT) and KD parasites under these stress conditions. Importantly, DHA induced transcriptional alteration of many genes involved in many aspects of stress responses, which were heavily shared among the altered genes under heat shock and low glucose conditions, including ART-resistance-related genes such as K13 and coronin . Based on the expression pattern between WT and KD parasites under three stress conditions, ∼300-400 genes were identified to be involved in PfGCN5-dependent, general and stress-condition-specific responses with high levels of overlaps among three stress conditions. Notably, using ring-stage survival assay (RSA), we found that KD or inhibition of PfGCN5 could sensitize the ART-resistant parasites to the DHA treatment. All these indicate that PfGCN5 is pivotal in regulating general and ART-resistance-related stress responses in malaria parasites, implicating PfGCN5 as a potential target for malaria intervention. IMPORTANCE Malaria leads to about half a million deaths annually and these casualties were majorly caused by the infection of Plasmodium falciparum . This parasite strives to survive by defending against a variety of stress conditions, such as malaria cyclical fever (heat shock), starvation due to low blood sugar (glucose) levels (hypoglycemia), and drug treatment. Previous studies have revealed that P. falciparum has developed unique stress responses to different stresses including ART treatment, and ART-resistant parasites harbor elevated stress responses. In this study, we provide critical evidence on the role of PfGCN5, a histone modifier, and a chromatin coactivator, in regulating general and stress-specific responses in malaria parasites, indicating that PfGCN5 can be used as a potential target for anti-malaria intervention.
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Ring-stage growth arrest: Metabolic basis of artemisinin tolerance in Plasmodium falciparum. iScience 2022; 26:105725. [PMID: 36579133 PMCID: PMC9791339 DOI: 10.1016/j.isci.2022.105725] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 10/09/2022] [Accepted: 11/30/2022] [Indexed: 12/09/2022] Open
Abstract
The emergence and spread of artemisinin-tolerant malaria parasites threatens malaria control programmes worldwide. Mutations in the propeller domain of the Kelch13 protein confer Plasmodium falciparum artemisinin resistance (ART-R). ART-R is linked to the reduced susceptibility of temporary growth-arrested ring-stage parasites, but the metabolic mechanisms remain elusive. We generated two PfKelch13 mutant lines via CRISPR-Cas9 gene editing which displayed a reduced susceptibility accompanied by an extended ring stage. The metabolome of ART-induced ring-stage growth arrest parasites carrying PfKelch13 mutations showed significant alterations in the tricarboxylic acid (TCA) cycle, glycolysis, and amino acids metabolism, pointing to altered energy and porphyrin metabolism with metabolic plasticity. The critical role of these pathways was further confirmed by altering metabolic flow or through chemical inhibition. Our findings uncover that the growth arrestment associated with ART-R is potentially attributed to the adaptative metabolic plasticity, indicating that the defined metabolic remodeling turns out to be the trigger for ART-R.
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Leski TA, Taitt CR, Colston SM, Bangura U, Holtz A, Yasuda CY, Reynolds ND, Lahai J, Lamin JM, Baio V, Ansumana R, Stenger DA, Vora GJ. Prevalence of malaria resistance-associated mutations in Plasmodium falciparum circulating in 2017–2018, Bo, Sierra Leone. Front Microbiol 2022; 13:1059695. [DOI: 10.3389/fmicb.2022.1059695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 11/17/2022] [Indexed: 12/05/2022] Open
Abstract
IntroductionIn spite of promising medical, sociological, and engineering strategies and interventions to reduce the burden of disease, malaria remains a source of significant morbidity and mortality, especially among children in sub-Saharan Africa. In particular, progress in the development and administration of chemotherapeutic agents is threatened by evolved resistance to most of the antimalarials currently in use, including artemisinins.MethodsThis study analyzed the prevalence of mutations associated with antimalarial resistance in Plasmodium falciparum from 95 clinical samples collected from individuals with clinically confirmed malaria at a hospital in Bo, Sierra Leone between May 2017 and December 2018. The combination of polymerase chain reaction amplification and subsequent high throughput DNA sequencing was used to determine the presence of resistance-associated mutations in five P. falciparum genes – pfcrt, pfmdr1, pfdhfr, pfdhps and pfkelch13. The geographic origin of parasites was assigned using mitochondrial sequences.ResultsRelevant mutations were detected in the pfcrt (22%), pfmdr1 (>58%), pfdhfr (100%) and pfdhps (>80%) genes while no resistance-associated mutations were found in the pfkelch13 gene. The mitochondrial barcodes were consistent with a West African parasite origin with one exception indicating an isolate imported from East Africa.DiscussionDetection of the pfmdr1 NFSND haplotype in 50% of the samples indicated the increasing prevalence of strains with elevated tolerance to artemeter + lumefantrine (AL) threatening the combination currently used to treat uncomplicated malaria in Sierra Leone. The frequency of mutations linked to resistance to antifolates suggests widespread resistance to the drug combination used for intermittent preventive treatment during pregnancy.
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Kassimu K, Milando F, Omolo J, Mdemu A, Nyaulingo G, Mbarak H, Mohamed L, Rashid R, Ahmed S, Rashid M, Msami H, Damiano D, Simon B, Mbaga T, Issa F, Lweno O, Balige N, Hassan O, Mwalimu B, Hamad A, Olotu A, Mårtensson A, Machumi F, Jongo S, Ngasala B, Abdulla S. Safety and Tolerability of an Antimalarial Herbal Remedy in Healthy Volunteers: An Open-Label, Single-Arm, Dose-Escalation Study on Maytenus senegalensis in Tanzania. Trop Med Infect Dis 2022; 7:tropicalmed7120396. [PMID: 36548651 PMCID: PMC9787516 DOI: 10.3390/tropicalmed7120396] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/15/2022] [Accepted: 11/21/2022] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Though Maytenus senegalensis is one of the medicinal plants widely used in traditional medicine to treat infectious and inflammatory diseases in Africa, there is a lack of safety data regarding its use. Therefore, the study aimed to asselss the safety and tolerability of the antimalarial herbal remedy M. senegalensis. MATERIAL AND METHODS The study design was an open-label, single-arm, dose-escalation. Twelve eligible male healthy Tanzanians aged 18 to 45 years were enrolled in four study dose groups. Volunteers' safety and tolerability post-investigational-product administration were monitored on days 0 to 7,14, and 56. RESULTS There were no deaths or serious adverse events in any of the study groups, nor any adverse events that resulted in premature discontinuation. The significant mean changes observed in WBC (p = 0.003), Neutrophils (p = 0.02), Lymphocytes (p = 0.001), Eosinophils (p = 0.009), Alanine aminotransferase (p = 0.002), Creatinine (p = 0.03) and Total bilirubin (p = 0.004) laboratory parameters were not associated with any signs of toxicity or clinical symptoms. CONCLUSIONS M. senegalensis was demonstrated to be safe and tolerable when administered at a dose of 800 mg every eight hours a day for four days. This study design may be adapted to evaluate other herbal remedies.
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Affiliation(s)
- Kamaka Kassimu
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam P.O. Box 65001, Tanzania
- Correspondence: or ; Tel.: +255-713-488-238
| | - Florence Milando
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Justin Omolo
- Department of Traditional Medicine, National Institute for Medical Research, Dar es Salaam P.O. Box 9653, Tanzania
| | - Abel Mdemu
- Department of Traditional Medicine, National Institute for Medical Research, Dar es Salaam P.O. Box 9653, Tanzania
| | - Gloria Nyaulingo
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Hussein Mbarak
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Latipha Mohamed
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Ramla Rashid
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Saumu Ahmed
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Mohammed Rashid
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Hania Msami
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - David Damiano
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Beatus Simon
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Thabit Mbaga
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Fatuma Issa
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Omar Lweno
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Neema Balige
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Omary Hassan
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Bakari Mwalimu
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Ali Hamad
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Ally Olotu
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Andreas Mårtensson
- Department of Women’s and Children’s Health, International Maternal and Child Health (IMCH), Uppsala University, S-751 85 Uppsala, Sweden
| | - Francis Machumi
- Institute of Traditional Medicine, Muhimbili University of Health and Allied Sciences, Dar es Salaam P.O. Box 65001, Tanzania
| | - Said Jongo
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
| | - Billy Ngasala
- Department of Parasitology and Medical Entomology, Muhimbili University of Health and Allied Sciences, Dar es Salaam P.O. Box 65001, Tanzania
- Department of Women’s and Children’s Health, International Maternal and Child Health (IMCH), Uppsala University, S-751 85 Uppsala, Sweden
| | - Salim Abdulla
- Bagamoyo Clinical Trial Facility, Ifakara Health Institute, Bagamoyo P.O. Box 74, Tanzania
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Lee WC, Russell B, Rénia L. Evolving perspectives on rosetting in malaria. Trends Parasitol 2022; 38:882-889. [PMID: 36031553 DOI: 10.1016/j.pt.2022.08.001] [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: 06/15/2022] [Revised: 08/01/2022] [Accepted: 08/01/2022] [Indexed: 11/26/2022]
Abstract
The ability of the intraerythrocytic Plasmodium spp. to form spontaneous rosettes with uninfected red blood cells (URBCs) has been observed in the medically important malaria parasites. Since the discovery of rosettes in the late 1980s, different formation mechanisms and pathobiological roles have been postulated for rosetting; most of which have focused on Plasmodium falciparum. Recent breakthroughs, including new data from Plasmodium vivax, have highlighted the multifaceted roles of rosetting in the immunopathobiology and the development of drug resistance in human malaria. Here, we provide new perspectives on the formation and the role of rosetting in malaria rheopathobiology.
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Affiliation(s)
- Wenn-Chyau Lee
- Department of Parasitology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia; A*STAR Infectious Diseases Labs, Agency for Science, Technology, and Research (A*STAR), Singapore.
| | - Bruce Russell
- Department of Microbiology and Immunology, University of Otago, Dunedin, Otago, New Zealand
| | - Laurent Rénia
- A*STAR Infectious Diseases Labs, Agency for Science, Technology, and Research (A*STAR), Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore.
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13
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Liang X, Boonhok R, Siddiqui FA, Xiao B, Li X, Qin J, Min H, Jiang L, Cui L, Miao J. A Leak-Free Inducible CRISPRi/a System for Gene Functional Studies in Plasmodium falciparum. Microbiol Spectr 2022; 10:e0278221. [PMID: 35510853 PMCID: PMC9241666 DOI: 10.1128/spectrum.02782-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 04/18/2022] [Indexed: 12/16/2022] Open
Abstract
By fusing catalytically dead Cas9 (dCas9) to active domains of histone deacetylase (Sir2a) or acetyltransferase (GCN5), this CRISPR interference/activation (CRISPRi/a) system allows gene regulation at the transcriptional level without causing permanent changes in the parasite genome. However, the constitutive expression of dCas9 poses a challenge for studying essential genes, which may lead to adaptive changes in the parasite, masking the true phenotypes. Here, we developed a leak-free inducible CRISPRi/a system by integrating the DiCre/loxP regulon to allow the expression of dCas9-GCN5/-Sir2a upon transient induction with rapamycin, which allows convenient transcriptional regulation of a gene of interest by introducing a guide RNA targeting its transcription start region. Using eight genes that are either silent or expressed from low to high levels during asexual erythrocytic development, we evaluated the robustness and versatility of this system in the asexual parasites. For most genes analyzed, this inducible CRISPRi/a system led to 1.5- to 3-fold up-or downregulation of the target genes at the mRNA level. Alteration in the expression of PfK13 and PfMYST resulted in altered sensitivities to artemisinin. For autophagy-related protein 18, an essential gene related to artemisinin resistance, a >2-fold up- or downregulation was obtained by inducible CRISPRi/a, leading to growth retardation. For the master regulator of gametocytogenesis, PfAP2-G, a >10-fold increase of the PfAP2-G transcripts was obtained by CRISPRa, resulting in >4-fold higher gametocytemia in the induced parasites. Additionally, inducible CRISPRi/a could also regulate gene expression in gametocytes. This inducible epigenetic regulation system offers a fast way of studying gene functions in Plasmodium falciparum. IMPORTANCE Understanding the fundamental biology of malaria parasites through functional genetic/genomic studies is critical for identifying novel targets for antimalarial development. Conditional knockout/knockdown systems are required to study essential genes in the haploid blood stages of the parasite. In this study, we developed an inducible CRISPRi/a system via the integration of DiCre/loxP. We evaluated the robustness and versatility of this system by activating or repressing eight selected genes and achieved up- and downregulation of the targeted genes located in both the euchromatin and heterochromatin regions. This system offers the malaria research community another tool for functional genetic studies.
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Affiliation(s)
- Xiaoying Liang
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Rachasak Boonhok
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Faiza Amber Siddiqui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Bo Xiao
- Unit of Human Parasite Molecular and Cell Biology, Key Laboratory of Molecular Virology and Immunology, Pasteur Institute of Shanghai, Chinese Academy of Sciences, Shanghai, People’s Republic of China
| | - Xiaolian Li
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Junling Qin
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Hui Min
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Lubin Jiang
- Unit of Human Parasite Molecular and Cell Biology, Key Laboratory of Molecular Virology and Immunology, Pasteur Institute of Shanghai, Chinese Academy of Sciences, Shanghai, People’s Republic of China
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
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14
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Brenneman KV, Li X, Kumar S, Delgado E, Checkley LA, Shoue DA, Reyes A, Abatiyow BA, Haile MT, Tripura R, Peto T, Lek D, Button-Simons KA, Kappe SH, Dhorda M, Nosten F, Nkhoma SC, Cheeseman IH, Vaughan AM, Ferdig MT, Anderson TJ. Optimizing bulk segregant analysis of drug resistance using Plasmodium falciparum genetic crosses conducted in humanized mice. iScience 2022; 25:104095. [PMID: 35372813 PMCID: PMC8971943 DOI: 10.1016/j.isci.2022.104095] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/24/2022] [Accepted: 03/11/2022] [Indexed: 01/15/2023] Open
Abstract
Classical malaria parasite genetic crosses involve isolation, genotyping, and phenotyping of progeny parasites, which is time consuming and laborious. We tested a rapid alternative approach-bulk segregant analysis (BSA)-that utilizes sequencing of bulk progeny populations with and without drug selection for rapid identification of drug resistance loci. We used dihydroartemisinin (DHA) selection in two genetic crosses and investigated how synchronization, cryopreservation, and the drug selection regimen impacted BSA success. We detected a robust quantitative trait locus (QTL) at kelch13 in both crosses but did not detect QTLs at four other candidate loci. QTLs were detected using synchronized, but not unsynchronized progeny pools, consistent with the stage-specific action of DHA. We also successfully applied BSA to cryopreserved progeny pools, expanding the utility of this approach. We conclude that BSA provides a powerful approach for investigating the genetic architecture of drug resistance in Plasmodium falciparum.
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Affiliation(s)
- Katelyn Vendrely Brenneman
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Xue Li
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Sudhir Kumar
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Elizabeth Delgado
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Lisa A. Checkley
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Douglas A. Shoue
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Ann Reyes
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Biley A. Abatiyow
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Meseret T. Haile
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
| | - Rupam Tripura
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
| | - Tom Peto
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
| | - Dysoley Lek
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
- School of Public Health, National Institute of Public Health, Phnom Penh, Cambodia
| | - Katrina A. Button-Simons
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
| | - Stefan H.I. Kappe
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - Mehul Dhorda
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
| | - François Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, UK
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Thailand
| | | | - Ian H. Cheeseman
- Program in Host Pathogen Interactions, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Ashley M. Vaughan
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, USA
- Department of Pediatrics, University of Washington, Seattle, WA, USA
- Corresponding author
| | - Michael T. Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, USA
- Corresponding author
| | - Tim J.C. Anderson
- Program in Disease Intervention and Prevention, Texas Biomedical Research Institute, San Antonio, TX, USA
- Corresponding author
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15
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Abstract
Emerging resistance to artemisinin (ART) has become a challenge for reducing worldwide malaria mortality and morbidity. The C580Y mutation in Plasmodium falciparum Kelch13 has been identified as the major determinant for ART resistance in the background of other mutations, which include the T38I mutation in autophagy-related protein PfATG18. Increased endoplasmic reticulum phosphatidylinositol-3-phosphate (ER-PI3P) vesiculation, unfolded protein response (UPR), and oxidative stress are the proteostasis mechanisms proposed to cause ART resistance. While UPR and PI3P are known to stimulate autophagy in higher organisms to clear misfolded proteins, participation of the parasite autophagy machinery in these mechanisms of ART resistance has not yet been experimentally demonstrated. Our study establishes that ART-induced ER stress leads to increased expression of P. falciparum autophagy proteins through induction of the UPR. Furthermore, the ART-resistant K13C580Y isolate shows higher basal expression levels of autophagy proteins than those of its isogenic counterpart, and this magnifies under starvation conditions. The copresence of PfK13 with PfATG18 and PI3P on parasite hemoglobin-trafficking vesicles demonstrate interactions between the autophagy and hemoglobin endocytosis pathways proposed to be involved in ART resistance. Analysis of PfK13 mutations in 2,517 field isolates, revealing an impressive >85% coassociation between PfK13 C580Y and PfATG18 T38I, together with our experimental studies with an ART-resistant P. falciparum strain establishes that parasite autophagy underpins various mechanisms of ART resistance and is a starting point to further explore this pathway for developing antimalarials.
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16
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Artemisinin resistance in the malaria parasite, Plasmodium falciparum, originates from its initial transcriptional response. Commun Biol 2022; 5:274. [PMID: 35347215 PMCID: PMC8960834 DOI: 10.1038/s42003-022-03215-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 02/16/2022] [Indexed: 12/30/2022] Open
Abstract
The emergence and spread of artemisinin-resistant Plasmodium falciparum, first in the Greater Mekong Subregion (GMS), and now in East Africa, is a major threat to global malaria elimination ambitions. To investigate the artemisinin resistance mechanism, transcriptome analysis was conducted of 577 P. falciparum isolates collected in the GMS between 2016–2018. A specific artemisinin resistance-associated transcriptional profile was identified that involves a broad but discrete set of biological functions related to proteotoxic stress, host cytoplasm remodelling, and REDOX metabolism. The artemisinin resistance-associated transcriptional profile evolved from initial transcriptional responses of susceptible parasites to artemisinin. The genetic basis for this adapted response is likely to be complex. Transcriptomic analysis of isolates from the malaria parasite (Plasmodium falciparum) in the Greater Mekong Subregion of Southeast Asia identifies gene expression patterns that are correlated with resistance to a common anti-malaria drug, artemisinin.
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Egwu CO, Pério P, Augereau JM, Tsamesidis I, Benoit-Vical F, Reybier K. Resistance to artemisinin in falciparum malaria parasites: A redox-mediated phenomenon. Free Radic Biol Med 2022; 179:317-327. [PMID: 34416340 DOI: 10.1016/j.freeradbiomed.2021.08.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 08/16/2021] [Indexed: 12/30/2022]
Abstract
Malaria remains a major public health disease due to its high yearly mortality and morbidity. Resistance to the gold standard drug, artemisinin, is worrisome and needs better understanding in order to be overcome. In this work, we sought to study whether redox processes are involved in artemisinin resistance. As artemisinin is known to act among others via production of reactive species, we first compared the production of reactive oxygen species and concomitant protein oxidation in artemisinin-sensitive and artemisinin-resistant parasites when treated with artemisinin. The results undoubtedly demonstrated, using different original methods, that the level of ROS, including superoxide production, and oxidized protein were lower in the resistant strain. Interestingly, the major in-between strain difference was reported at the earlier ring stages, which are the forms able to enter in a quiescence state according to the ART resistance phenomenon. Moreover, we demonstrated a better homeostasis regulation in relation with higher expression of antioxidants in the artemisinin-resistant parasites than their sensitive counterparts after artemisinin exposure, notably, superoxide dismutase and the glutathione (GSH) system. These findings enrich the body of knowledges about the multifaceted mechanism of artemisinin resistance and will help in the design and development of newer antimalarials strategies active against resistant parasites.
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Affiliation(s)
- Chinedu O Egwu
- PharmaDev, UMR 152, Université de Toulouse, IRD, UPS, Toulouse, 31400, France; Medical Biochemistry, College of Medicine, Alex-Ekwueme Federal University, Ndufu-Alike Ikwo, Abakaliki, Ebonyi State, Nigeria; LCC-CNRS, Laboratoire de Chimie de Coordination, Université de Toulouse, CNRS, Toulouse, France; MAAP, Inserm ERL 1289, New Antimalarial Molecules and Pharmacological Approaches, Toulouse, France; Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France
| | - Pierre Pério
- PharmaDev, UMR 152, Université de Toulouse, IRD, UPS, Toulouse, 31400, France
| | - Jean-Michel Augereau
- LCC-CNRS, Laboratoire de Chimie de Coordination, Université de Toulouse, CNRS, Toulouse, France; MAAP, Inserm ERL 1289, New Antimalarial Molecules and Pharmacological Approaches, Toulouse, France; Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France
| | - Ioannis Tsamesidis
- PharmaDev, UMR 152, Université de Toulouse, IRD, UPS, Toulouse, 31400, France
| | - Françoise Benoit-Vical
- LCC-CNRS, Laboratoire de Chimie de Coordination, Université de Toulouse, CNRS, Toulouse, France; MAAP, Inserm ERL 1289, New Antimalarial Molecules and Pharmacological Approaches, Toulouse, France; Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France.
| | - Karine Reybier
- PharmaDev, UMR 152, Université de Toulouse, IRD, UPS, Toulouse, 31400, France.
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Egwu CO, Obasi NA, Aloke C, Nwafor J, Tsamesidis I, Chukwu J, Elom S. Impact of Drug Pressure versus Limited Access to Drug in Malaria Control: The Dilemma. MEDICINES (BASEL, SWITZERLAND) 2022; 9:medicines9010002. [PMID: 35049935 PMCID: PMC8779401 DOI: 10.3390/medicines9010002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/24/2021] [Accepted: 12/27/2021] [Indexed: 11/16/2022]
Abstract
Malaria burden has severe impact on the world. Several arsenals, including the use of antimalarials, are in place to curb the malaria burden. However, the application of these antimalarials has two extremes, limited access to drug and drug pressure, which may have similar impact on malaria control, leading to treatment failure through divergent mechanisms. Limited access to drugs ensures that patients do not get the right doses of the antimalarials in order to have an effective plasma concentration to kill the malaria parasites, which leads to treatment failure and overall reduction in malaria control via increased transmission rate. On the other hand, drug pressure can lead to the selection of drug resistance phenotypes in a subpopulation of the malaria parasites as they mutate in order to adapt. This also leads to a reduction in malaria control. Addressing these extremes in antimalarial application can be essential in maintaining the relevance of the conventional antimalarials in winning the war against malaria.
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Affiliation(s)
- Chinedu Ogbonnia Egwu
- PharmaDev, UMR 152, Université de Toulouse, IRD, UPS, 31400 Toulouse, France
- Medical Biochemistry, College of Medicine, Alex-Ekwueme Federal University, Ndufu-Alike Ikwo, P.M.B. 1010, Abakaliki 482131, Nigeria; (N.A.O.); (C.A.); (S.E.)
- Correspondence:
| | - Nwogo Ajuka Obasi
- Medical Biochemistry, College of Medicine, Alex-Ekwueme Federal University, Ndufu-Alike Ikwo, P.M.B. 1010, Abakaliki 482131, Nigeria; (N.A.O.); (C.A.); (S.E.)
| | - Chinyere Aloke
- Medical Biochemistry, College of Medicine, Alex-Ekwueme Federal University, Ndufu-Alike Ikwo, P.M.B. 1010, Abakaliki 482131, Nigeria; (N.A.O.); (C.A.); (S.E.)
- Protein Structure-Function and Research Unit, School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Braamfontein, Johannesburg 2050, South Africa
| | - Joseph Nwafor
- Anatomy, College of Medicine, Alex-Ekwueme Federal University, Ndufu-Alike Ikwo, P.M.B. 1010, Abakaliki 482131, Nigeria;
| | - Ioannis Tsamesidis
- Department of Prosthodontics, School of Dentistry, Faculty of Health Sciences, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece;
| | - Jennifer Chukwu
- John Hopkins Program on International Education in Gynaecology and Obstetrics, Abuja 900281, Nigeria;
| | - Sunday Elom
- Medical Biochemistry, College of Medicine, Alex-Ekwueme Federal University, Ndufu-Alike Ikwo, P.M.B. 1010, Abakaliki 482131, Nigeria; (N.A.O.); (C.A.); (S.E.)
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Lee WC, Russell B, Lee B, Chu CS, Phyo AP, Sriprawat K, Lau YL, Nosten F, Rénia L. Plasmodium falciparum rosetting protects schizonts against artemisinin. EBioMedicine 2021; 73:103680. [PMID: 34749300 PMCID: PMC8586750 DOI: 10.1016/j.ebiom.2021.103680] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/04/2021] [Accepted: 10/25/2021] [Indexed: 11/24/2022] Open
Abstract
Background Artemisinin (ART) resistance in Plasmodium falciparum is thought to occur during the early stage of the parasite's erythrocytic cycle. Here, we identify a novel factor associated with the late stage parasite development that contributes to ART resistance. Methods Rosetting rates of clinical isolates pre- and post- brief (one hour) exposure to artesunate (AS, an ART derivative) were evaluated. The effects of AS-mediated rosetting on the post-AS-exposed parasite's replication and survival, as well as the extent of protection by AS-mediated rosetting on different parasite stages were investigated. The rosetting ligands, mechanisms, and gene mutations involved were studied. Findings Brief AS exposure stimulated rosetting, with AS-resistant isolates forming more rosettes in a more rapid manner. AS-mediated rosetting enabled infected erythrocytes (IRBC) to withstand AS exposure for several hours and protected the IRBC from phagocytosis. When their rosetting ability was blocked experimentally, the post-AS exposure survival advantage by the AS-resistant parasites was abrogated. Deletions in two genes coding for PfEMP1 exon 2 (PF3D7_0200300 and PF3D7_0223300) were found to be associated with AS-mediated rosetting, and these mutations were significantly selected through time in the parasite population under study, along with the K13 mutations, a molecular marker of ART-resistance. Interpretation Rapid ART parasite clearance is driven by the direct oxidative damages on IRBC by ART and the phagocytic destruction of the damaged IRBC. Rosetting serves as a rapid ‘buying time’ strategy that allows more parasites to complete schizont maturation, reinvasion and subsequent development into the intrinsically less ART-susceptible ring stage. Funding A*STAR, NMRC-OF-YIRG, HRC e-ASIA, Wellcome.
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Affiliation(s)
- Wenn-Chyau Lee
- A*STAR Infectious Diseases Labs, Agency for Science, Technology and Research (A*STAR), Singapore; Singapore Immunology Network (SIgN), A*STAR, Singapore.
| | - Bruce Russell
- Department of Microbiology and Immunology, University of Otago, Dunedin, Otago, New Zealand
| | - Bernett Lee
- Singapore Immunology Network (SIgN), A*STAR, Singapore
| | - Cindy S Chu
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand; Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Aung Pyae Phyo
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand; Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Kanlaya Sriprawat
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand
| | - Yee-Ling Lau
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - François Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, Thailand; Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Laurent Rénia
- A*STAR Infectious Diseases Labs, Agency for Science, Technology and Research (A*STAR), Singapore; Singapore Immunology Network (SIgN), A*STAR, Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore.
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20
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Kekessie FK, Amengor CDK, Brobbey A, Addotey JN, Danquah CA, Peprah P, Harley BK, Ben IO, Zoiku FK, Borquaye LS, Gasu EN, Ofori-Attah E, Tetteh M. Synthesis, molecular docking studies and ADME prediction of some new triazoles as potential antimalarial agents. SCIENTIFIC AFRICAN 2021. [DOI: 10.1016/j.sciaf.2021.e00998] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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21
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Siddiqui FA, Liang X, Cui L. Plasmodium falciparum resistance to ACTs: Emergence, mechanisms, and outlook. Int J Parasitol Drugs Drug Resist 2021; 16:102-118. [PMID: 34090067 PMCID: PMC8188179 DOI: 10.1016/j.ijpddr.2021.05.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 04/06/2021] [Accepted: 05/21/2021] [Indexed: 01/18/2023]
Abstract
Emergence and spread of resistance in Plasmodium falciparum to the frontline treatment artemisinin-based combination therapies (ACTs) in the epicenter of multidrug resistance of Southeast Asia threaten global malaria control and elimination. Artemisinin (ART) resistance (or tolerance) is defined clinically as delayed parasite clearance after treatment with an ART drug. The resistance phenotype is restricted to the early ring stage and can be measured in vitro using a ring-stage survival assay. ART resistance is associated with mutations in the propeller domain of the Kelch family protein K13. As a pro-drug, ART is activated primarily by heme, which is mainly derived from hemoglobin digestion in the food vacuole. Activated ARTs can react promiscuously with a wide range of cellular targets, disrupting cellular protein homeostasis. Consistent with this mode of action for ARTs, the molecular mechanisms of K13-mediated ART resistance involve reduced hemoglobin uptake/digestion and increased cellular stress response. Mutations in other genes such as AP-2μ (adaptor protein-2 μ subunit), UBP-1 (ubiquitin-binding protein-1), and Falcipain 2a that interfere with hemoglobin uptake and digestion also increase resistance to ARTs. ART resistance has facilitated the development of resistance to the partner drugs, resulting in rapidly declining ACT efficacies. The molecular markers for resistance to the partner drugs are mostly associated with point mutations in the two food vacuole membrane transporters PfCRT and PfMDR1, and amplification of pfmdr1 and the two aspartic protease genes plasmepsin 2 and 3. It has been observed that mutations in these genes can have opposing effects on sensitivities to different partner drugs, which serve as the principle for designing triple ACTs and drug rotation. Although clinical ACT resistance is restricted to Southeast Asia, surveillance for drug resistance using in vivo clinical efficacy, in vitro assays, and molecular approaches is required to prevent or slow down the spread of resistant parasites.
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Affiliation(s)
- Faiza Amber Siddiqui
- Department of Internal Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Xiaoying Liang
- Department of Internal Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Liwang Cui
- Department of Internal Medicine, University of South Florida, Tampa, FL, 33612, USA.
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22
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Abstract
Although the last two decades have seen a substantial decline in malaria incidence and mortality due to the use of insecticide-treated bed nets and artemisinin combination therapy, the threat of drug resistance is a constant obstacle to sustainable malaria control. Given that patients can die quickly from this disease, public health officials and doctors need to understand whether drug resistance exists in the parasite population, as well as how prevalent it is so they can make informed decisions about treatment. As testing for drug efficacy before providing treatment to malaria patients is impractical, researchers need molecular markers of resistance that can be more readily tracked in parasite populations. To this end, much work has been done to unravel the genetic underpinnings of drug resistance in Plasmodium falciparum. The aim of this review is to provide a broad overview of common genomic approaches that have been used to discover the alleles that drive drug response phenotypes in the most lethal human malaria parasite.
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Affiliation(s)
- Frances Rocamora
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Elizabeth A Winzeler
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, California 92093, USA
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23
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Owolabi ATY, Reece SE, Schneider P. Daily rhythms of both host and parasite affect antimalarial drug efficacy. Evol Med Public Health 2021; 9:208-219. [PMID: 34285807 PMCID: PMC8284615 DOI: 10.1093/emph/eoab013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 04/23/2021] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Circadian rhythms contribute to treatment efficacy in several non-communicable diseases. However, chronotherapy (administering drugs at a particular time-of-day) against infectious diseases has been overlooked. Yet, the daily rhythms of both hosts and disease-causing agents can impact the efficacy of drug treatment. We use the rodent malaria parasite Plasmodium chabaudi, to test whether the daily rhythms of hosts, parasites and their interactions affect sensitivity to the key antimalarial, artemisinin. METHODOLOGY Asexual malaria parasites develop rhythmically in the host's blood, in a manner timed to coordinate with host daily rhythms. Our experiments coupled or decoupled the timing of parasite and host rhythms, and we administered artemisinin at different times of day to coincide with when parasites were either at an early (ring) or later (trophozoite) developmental stage. We quantified the impacts of parasite developmental stage, and alignment of parasite and host rhythms, on drug sensitivity. RESULTS We find that rings were less sensitive to artemisinin than trophozoites, and this difference was exacerbated when parasite and host rhythms were misaligned, with little direct contribution of host time-of-day on its own. Furthermore, the blood concentration of haem at the point of treatment correlated positively with artemisinin efficacy but only when parasite and host rhythms were aligned. CONCLUSIONS AND IMPLICATIONS Parasite rhythms influence drug sensitivity in vivo. The hitherto unknown modulation by alignment between parasite and host daily rhythms suggests that disrupting the timing of parasite development could be a novel chronotherapeutic approach. LAY SUMMARY We reveal that chronotherapy (providing medicines at a particular time-of-day) could improve treatment for malaria infections. Specifically, parasites' developmental stage at the time of treatment and the coordination of timing between parasite and host both affect how well antimalarial drug treatment works.
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Affiliation(s)
- Alíz T Y Owolabi
- Institute of Evolutionary Biology & Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK,Corresponding author. Institute of Evolutionary Biology & Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Charlotte Auerbach Road, Edinburgh, EH9 3FL, UK. Tel (office): +441316508642; E-mail:
| | - Sarah E Reece
- Institute of Evolutionary Biology & Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK
| | - Petra Schneider
- Institute of Evolutionary Biology & Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK
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24
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Neal ML, Wei L, Peterson E, Arrieta-Ortiz ML, Danziger S, Baliga N, Kaushansky A, Aitchison J. A systems-level gene regulatory network model for Plasmodium falciparum. Nucleic Acids Res 2021; 49:4891-4906. [PMID: 33450011 PMCID: PMC8136813 DOI: 10.1093/nar/gkaa1245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 10/26/2020] [Accepted: 01/06/2021] [Indexed: 12/30/2022] Open
Abstract
Many of the gene regulatory processes of Plasmodium falciparum, the deadliest malaria parasite, remain poorly understood. To develop a comprehensive guide for exploring this organism's gene regulatory network, we generated a systems-level model of P. falciparum gene regulation using a well-validated, machine-learning approach for predicting interactions between transcription regulators and their targets. The resulting network accurately predicts expression levels of transcriptionally coherent gene regulatory programs in independent transcriptomic data sets from parasites collected by different research groups in diverse laboratory and field settings. Thus, our results indicate that our gene regulatory model has predictive power and utility as a hypothesis-generating tool for illuminating clinically relevant gene regulatory mechanisms within P. falciparum. Using the set of regulatory programs we identified, we also investigated correlates of artemisinin resistance based on gene expression coherence. We report that resistance is associated with incoherent expression across many regulatory programs, including those controlling genes associated with erythrocyte-host engagement. These results suggest that parasite populations with reduced artemisinin sensitivity are more transcriptionally heterogenous. This pattern is consistent with a model where the parasite utilizes bet-hedging strategies to diversify the population, rendering a subpopulation more able to navigate drug treatment.
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Affiliation(s)
| | | | | | | | | | | | | | - John D Aitchison
- To whom correspondence should be addressed. Tel: +1 206 884 3125; Fax: +1 206 884 3104;
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25
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Transmission of Artemisinin-Resistant Malaria Parasites to Mosquitoes under Antimalarial Drug Pressure. Antimicrob Agents Chemother 2020; 65:AAC.00898-20. [PMID: 33139275 PMCID: PMC7927852 DOI: 10.1128/aac.00898-20] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 10/20/2020] [Indexed: 12/24/2022] Open
Abstract
Resistance to artemisinin-based combination therapy (ACT) in the Plasmodium falciparum parasite is threatening to reverse recent gains in reducing global deaths from malaria. While resistance manifests as delayed parasite clearance in patients, the phenotype can only spread geographically via the sexual stages and mosquito transmission. In addition to their asexual killing properties, artemisinin and its derivatives sterilize sexual male gametocytes. Whether resistant parasites overcome this sterilizing effect has not, however, been fully tested. Resistance to artemisinin-based combination therapy (ACT) in the Plasmodium falciparum parasite is threatening to reverse recent gains in reducing global deaths from malaria. While resistance manifests as delayed parasite clearance in patients, the phenotype can only spread geographically via the sexual stages and mosquito transmission. In addition to their asexual killing properties, artemisinin and its derivatives sterilize sexual male gametocytes. Whether resistant parasites overcome this sterilizing effect has not, however, been fully tested. Here, we analyzed P. falciparum clinical isolates from the Greater Mekong Subregion, each demonstrating delayed clinical clearance and known resistance-associated polymorphisms in the Kelch13 (PfK13var) gene. As well as demonstrating reduced asexual sensitivity to drug, certain PfK13var isolates demonstrated a marked reduction in sensitivity to artemisinin in an in vitro male gamete formation assay. Importantly, this same reduction in sensitivity was observed when the most resistant isolate was tested directly in mosquito feeds. These results indicate that, under artemisinin drug pressure, while sensitive parasites are blocked, resistant parasites continue transmission. This selective advantage for resistance transmission could favor acquisition of additional host-specificity or polymorphisms affecting partner drug sensitivity in mixed infections. Favored resistance transmission under ACT coverage could have profound implications for the spread of multidrug-resistant malaria beyond Southeast Asia.
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26
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Ansbro MR, Itkin Z, Chen L, Zahoranszky-Kohalmi G, Amaratunga C, Miotto O, Peryea T, Hobbs CV, Suon S, Sá JM, Dondorp AM, van der Pluijm RW, Wellems TE, Simeonov A, Eastman RT. Modulation of Triple Artemisinin-Based Combination Therapy Pharmacodynamics by Plasmodium falciparum Genotype. ACS Pharmacol Transl Sci 2020; 3:1144-1157. [PMID: 33344893 PMCID: PMC7737215 DOI: 10.1021/acsptsci.0c00110] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Indexed: 01/19/2023]
Abstract
The first-line treatments for uncomplicated Plasmodium falciparum malaria are artemisinin-based combination therapies (ACTs), consisting of an artemisinin derivative combined with a longer acting partner drug. However, the spread of P. falciparum with decreased susceptibility to artemisinin and partner drugs presents a significant challenge to malaria control efforts. To stem the spread of drug resistant parasites, novel chemotherapeutic strategies are being evaluated, including the implementation of triple artemisinin-based combination therapies (TACTs). Currently, there is limited knowledge on the pharmacodynamic and pharmacogenetic interactions of proposed TACT drug combinations. To evaluate these interactions, we established an in vitro high-throughput process for measuring the drug concentration-response to three distinct antimalarial drugs present in a TACT. Sixteen different TACT combinations were screened against 15 parasite lines from Cambodia, with a focus on parasites with differential susceptibilities to piperaquine and artemisinins. Analysis revealed drug-drug interactions unique to specific genetic backgrounds, including antagonism between piperaquine and pyronaridine associated with gene amplification of plasmepsin II/III, two aspartic proteases that localize to the parasite digestive vacuole. From this initial study, we identified parasite genotypes with decreased susceptibility to specific TACTs, as well as potential TACTs that display antagonism in a genotype-dependent manner. Our assay and analysis platform can be further leveraged to inform drug implementation decisions and evaluate next-generation TACTs.
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Affiliation(s)
- Megan R. Ansbro
- Laboratory of Malaria
and Vector Research, National Institute of Allergy and Infectious
Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
- Wellcome Sanger Institute, Hinxton CB10 1SA, U.K.
| | - Zina Itkin
- National
Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Lu Chen
- National
Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Gergely Zahoranszky-Kohalmi
- National
Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Chanaki Amaratunga
- Laboratory of Malaria
and Vector Research, National Institute of Allergy and Infectious
Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Olivo Miotto
- Wellcome Sanger Institute, Hinxton CB10 1SA, U.K.
- Mahidol-Oxford Tropical Medicine Research
Unit, Faculty of Tropical Medicine, Mahidol
University, Bangkok 10400, Thailand
- Centre
for Tropical Medicine and Global Health, Nuffield Department of Medicine
Research, University of Oxford, Oxford OX3 7LF, U.K.
- Medical Research Council (MRC) Centre for Genomics and
Global Health, University of Oxford, Oxford OX3 7BN, U.K.
| | - Tyler Peryea
- National
Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Charlotte V. Hobbs
- Division of Infectious Diseases, Children’s
Hospital, University of Mississippi Medical
Center, Jackson, Mississippi 39216, United States
| | - Seila Suon
- National Center for Parasitology, Entomology,
and Malaria Control, Phnom Penh, Cambodia
| | - Juliana M. Sá
- Laboratory of Malaria
and Vector Research, National Institute of Allergy and Infectious
Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Arjen M. Dondorp
- Mahidol-Oxford Tropical Medicine Research
Unit, Faculty of Tropical Medicine, Mahidol
University, Bangkok 10400, Thailand
- Centre
for Tropical Medicine and Global Health, Nuffield Department of Medicine
Research, University of Oxford, Oxford OX3 7LF, U.K.
| | - Rob W. van der Pluijm
- Mahidol-Oxford Tropical Medicine Research
Unit, Faculty of Tropical Medicine, Mahidol
University, Bangkok 10400, Thailand
- Centre
for Tropical Medicine and Global Health, Nuffield Department of Medicine
Research, University of Oxford, Oxford OX3 7LF, U.K.
| | - Thomas E. Wellems
- Laboratory of Malaria
and Vector Research, National Institute of Allergy and Infectious
Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Anton Simeonov
- National
Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Richard T. Eastman
- National
Center for Advancing Translational Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, United States
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27
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Rosenthal MR, Ng CL. Plasmodium falciparum Artemisinin Resistance: The Effect of Heme, Protein Damage, and Parasite Cell Stress Response. ACS Infect Dis 2020; 6:1599-1614. [PMID: 32324369 DOI: 10.1021/acsinfecdis.9b00527] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Despite a significant decline in morbidity and mortality over the last two decades, in 2018 there were 228 million reported cases of malaria and 405000 malaria-related deaths. Artemisinin, the cornerstone of artemisinin-based combination therapies, is the most potent drug in the antimalarial armamentarium against falciparum malaria. Heme-mediated activation of artemisinin and its derivatives results in widespread parasite protein alkylation, which is thought to lead to parasite death. Alarmingly, cases of decreased artemisinin efficacy have been widely detected across Cambodia and in neighboring countries, and a few cases have been reported in the Guiana Shield, India, and Africa. The grim prospect of widespread artemisinin resistance propelled a concerted effort to understand the mechanisms of artemisinin action and resistance. The identification of genetic markers and the knowledge of molecular mechanisms underpinning artemisinin resistance allow prospective surveillance and inform future drug development strategies, respectively. Here, we highlight recent advances in our understanding of how parasite vesicle trafficking, hemoglobin digestion, and cell stress responses contribute to artemisinin resistance.
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Affiliation(s)
- Melissa R. Rosenthal
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Caroline L. Ng
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
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28
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Hassett MR, Roepe PD. Origin and Spread of Evolving Artemisinin-Resistant Plasmodium falciparum Malarial Parasites in Southeast Asia. Am J Trop Med Hyg 2020; 101:1204-1211. [PMID: 31642425 DOI: 10.4269/ajtmh.19-0379] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In this review, we provide an epidemiological history of the emergence and ongoing spread of evolving Plasmodium falciparum artemisinin resistance (ARTR). Southeast Asia has been the focal point for emergence and spread of multiple antimalarial drug resistance phenomena, and is once again for evolving ARTR, also known as the "delayed clearance phenotype" (DCP). The five countries most impacted, Cambodia, Thailand, Myanmar, Laos, and Vietnam, each have complex histories of antimalarial drug use over many decades, which have in part molded the use of various artemisinin combination therapies (ACTs) within each country. We catalog the use of ACTs, evolving loss of ACT efficacy, and the frequency of pfk13 mutations (mutations associated with ARTR) in the Greater Mekong Subregion and map the historical spread of ARTR/DCP parasites. These data should assist improved surveillance and deployment of next-generation ACTs.
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Affiliation(s)
- Matthew R Hassett
- Department of Biochemistry and Cellular and Molecular Biology, Georgetown University, Washington, District of Columbia.,Department of Chemistry, Georgetown University, Washington, District of Columbia
| | - Paul D Roepe
- Department of Chemistry, Georgetown University, Washington, District of Columbia.,Department of Biochemistry and Cellular and Molecular Biology, Georgetown University, Washington, District of Columbia
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29
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Role of Plasmodium falciparum Kelch 13 Protein Mutations in P. falciparum Populations from Northeastern Myanmar in Mediating Artemisinin Resistance. mBio 2020; 11:mBio.01134-19. [PMID: 32098812 PMCID: PMC7042691 DOI: 10.1128/mbio.01134-19] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Artemisinin resistance has emerged in Southeast Asia, endangering the substantial progress in malaria elimination worldwide. It is associated with mutations in the PfK13 protein, but how PfK13 mediates artemisinin resistance is not completely understood. Here we used a new antibody against PfK13 to show that the PfK13 protein is expressed in all stages of the asexual intraerythrocytic cycle as well as in gametocytes and is partially localized in the endoplasmic reticulum. By introducing four PfK13 mutations into the 3D7 strain and reverting these mutations in field parasite isolates, we determined the impacts of these mutations identified in the parasite populations from northern Myanmar on the ring stage using the in vitro ring survival assay. The introduction of the N458Y mutation into the 3D7 background significantly increased the survival rates of the ring-stage parasites but at the cost of the reduced fitness of the parasites. Introduction of the F446I mutation, the most prevalent PfK13 mutation in northern Myanmar, did not result in a significant increase in ring-stage survival after exposure to dihydroartemisinin (DHA), but these parasites showed extended ring-stage development. Further, parasites with the F446I mutation showed only a marginal loss of fitness, partially explaining its high frequency in northern Myanmar. Conversely, reverting all these mutations, except for the C469Y mutation, back to their respective wild types reduced the ring-stage survival of these isolates in response to in vitro DHA treatment. Mutations in the Plasmodium falciparum Kelch 13 (PfK13) protein are associated with artemisinin resistance. PfK13 is essential for asexual erythrocytic development, but its function is not known. We tagged the PfK13 protein with green fluorescent protein in P. falciparum to study its expression and localization in asexual and sexual stages. We used a new antibody against PfK13 to show that the PfK13 protein is expressed ubiquitously in both asexual erythrocytic stages and gametocytes and is localized in punctate structures, partially overlapping an endoplasmic reticulum marker. We introduced into the 3D7 strain four PfK13 mutations (F446I, N458Y, C469Y, and F495L) identified in parasites from the China-Myanmar border area and characterized the in vitro artemisinin response phenotypes of the mutants. We found that all the parasites with the introduced PfK13 mutations showed higher survival rates in the ring-stage survival assay (RSA) than the wild-type (WT) control, but only parasites with N458Y displayed a significantly higher RSA value (26.3%) than the WT control. After these PfK13 mutations were reverted back to the WT in field parasite isolates, all revertant parasites except those with the C469Y mutation showed significantly lower RSA values than their respective parental isolates. Although the 3D7 parasites with introduced F446I, the predominant PfK13 mutation in northern Myanmar, did not show significantly higher RSA values than the WT, they had prolonged ring-stage development and showed very little fitness cost in in vitro culture competition assays. In comparison, parasites with the N458Y mutations also had a prolonged ring stage and showed upregulated resistance pathways in response to artemisinin, but this mutation produced a significant fitness cost, potentially leading to their lower prevalence in the Greater Mekong subregion.
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30
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Sharma M, Prasher P. An epigrammatic status of the ' azole'-based antimalarial drugs. RSC Med Chem 2020; 11:184-211. [PMID: 33479627 PMCID: PMC7536834 DOI: 10.1039/c9md00479c] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 11/26/2019] [Indexed: 11/21/2022] Open
Abstract
The development of multidrug resistance in the malarial parasite has sabotaged majority of the eradication efforts by restraining the inhibition profile of first line as well as second line antimalarial drugs, thus necessitating the development of novel pharmaceutics constructed on appropriate scaffolds with superior potency against the drug-resistant and drug-susceptible Plasmodium parasite. Over the past decades, the infectious malarial parasite has developed resistance against most of the contemporary therapeutics, thus necessitating the rational development of novel approaches principally focused on MDR malaria. This review presents an epigrammatic collation of the epidemiology and the contemporary antimalarial therapeutics based on the 'azole' motif.
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Affiliation(s)
- Mousmee Sharma
- Department of Chemistry , Uttaranchal University , Dehradun 248007 , India
- UGC Sponsored Centre for Advanced Studies , Department of Chemistry , Guru Nanak Dev University , Amritsar 143005 , India
| | - Parteek Prasher
- Department of Chemistry , University of Petroleum & Energy Studies , Dehradun 248007 , India . ;
- UGC Sponsored Centre for Advanced Studies , Department of Chemistry , Guru Nanak Dev University , Amritsar 143005 , India
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31
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Rosenberg A, Luth MR, Winzeler EA, Behnke M, Sibley LD. Evolution of resistance in vitro reveals mechanisms of artemisinin activity in Toxoplasma gondii. Proc Natl Acad Sci U S A 2019; 116:26881-26891. [PMID: 31806760 PMCID: PMC6936365 DOI: 10.1073/pnas.1914732116] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Artemisinins are effective against a variety of parasites and provide the first line of treatment for malaria. Laboratory studies have identified several mechanisms for artemisinin resistance in Plasmodium falciparum, including mutations in Kelch13 that are associated with delayed clearance in some clinical isolates, although other mechanisms are likely involved. To explore other potential mechanisms of resistance in parasites, we took advantage of the genetic tractability of Toxoplasma gondii, a related parasite that shows moderate sensitivity to artemisinin. Resistant populations of T. gondii were selected by culture in increasing concentrations and whole-genome sequencing identified several nonconservative point mutations that emerged in the population and were fixed over time. Genome editing using CRISPR/Cas9 was used to introduce point mutations conferring amino acid changes in a serine protease homologous to DegP and a serine/threonine protein kinase of unknown function. Single and double mutations conferred a competitive advantage over wild-type parasites in the presence of drug, despite not changing EC50 values. Additionally, the evolved resistant lines showed dramatic amplification of the mitochondria genome, including genes encoding cytochrome b and cytochrome c oxidase I. Prior studies in yeast and mammalian tumor cells implicate the mitochondrion as a target of artemisinins, and treatment of wild-type parasites with high concentrations of drug decreased mitochondrial membrane potential, a phenotype that was stably altered in the resistant parasites. These findings extend the repertoire of mutations associated with artemisinin resistance and suggest that the mitochondrion may be an important target of inhibition of resistance in T. gondii.
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Affiliation(s)
- Alex Rosenberg
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110
| | - Madeline R. Luth
- Department of Pediatrics, School of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Elizabeth A. Winzeler
- Department of Pediatrics, School of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Michael Behnke
- Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803
| | - L. David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110
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32
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Pacheco C, Moreno J, Herrera F. A high number of pfmdr1 gene copies in P. falciparum from Venezuela. Parasitol Res 2019; 118:3085-3089. [PMID: 31396714 DOI: 10.1007/s00436-019-06409-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 07/25/2019] [Indexed: 10/26/2022]
Abstract
Multidrug resistance in Plasmodium falciparum has been associated with gene amplification of pfmdr1. We studied the corresponding gene amplification in P. falciparum from blood samples of malaria patients in the Sifontes Municipality, Bolívar State, Venezuela, known as the highest region of incidence of malaria. Fifty-five P. falciparum DNA samples were extracted from different hosts and used for qPCR assessment of the copy number of pfmdr1. The assay detected four copies of the multidrug-resistant line P. falciparum Dd2 in comparison with the P. falciparum 3D7 that had only one copy. In the patients' samples, the copy number of pfmdr1 was a single copy in 80% and 20% left distributed in different copy numbers up to seven.
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Affiliation(s)
- César Pacheco
- Instituto de Investigaciones Biomédicas (BIOMED), Facultad de Ciencias de la Salud, Universidad de Carabobo, Núcleo Aragua, Maracay, 2101, Venezuela
| | - Jorge Moreno
- Centro de Investigaciones de Campo "Dr. Francesco Vitanza", Servicio Autónomo Instituto de Altos Estudios "Dr. Arnoldo Gabaldon", MPPS, Tumeremo, Bolívar, Venezuela
| | - Flor Herrera
- Instituto de Investigaciones Biomédicas (BIOMED), Facultad de Ciencias de la Salud, Universidad de Carabobo, Núcleo Aragua, Maracay, 2101, Venezuela.
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Zhu W, Li Y, Zhao D, Li H, Zhang W, Xu J, Hou J, Feng X, Wang H. Dihydroartemisinin suppresses glycolysis of LNCaP cells by inhibiting PI3K/AKT pathway and downregulating HIF-1α expression. Life Sci 2019; 233:116730. [PMID: 31390552 DOI: 10.1016/j.lfs.2019.116730] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 07/26/2019] [Accepted: 08/03/2019] [Indexed: 01/09/2023]
Abstract
AIMS Dihydroartemisinin (DHA) exhibits potential anticancer activity. However, the biological functions of DHA in prostate cancer remain largely unexplored. In this study, we aim to investigate the anti-proliferative effect and glycolysis regulation of DHA on prostate cancer cell LNCaP. MAIN METHODS Cell proliferative activity and apoptosis inducing were detected. The gene expression was detected by mRNA microarray and results were analyzed by GO and KEGG pathway database. Expressions of glycolysis key enzymes and PI3K/AKT/HIF-1α were detected by Western blot. KEY FINDINGS Results indicated that DHA could inhibit the LNCaP cell proliferation considerably and induce cell apoptosis. mRNA microarray showed 1293 genes were upregulated and 2322 genes were downregulated. GO and KEGG enrichment analysis suggested that glycolysis pathway was correlated with DHA inhibited the proliferation on the LNCaP cell. Western blot results showed that DHA can decrease GLUT1 and regulatory enzymes of glycolytic pathway expression probably by suppressing the activity of the intracellular Akt/mTOR and HIF-1 α. SIGNIFICANCE Experimental validation results indicate that DHA treatment can inhibit the LNCaP cell proliferation and induce apoptosis, which may be related to glycolysis inhibition.
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Affiliation(s)
- Wenhe Zhu
- Jilin Medical University, Ji Lin, China
| | - Yawei Li
- Jilin Medical University, Ji Lin, China
| | | | - Huilin Li
- Jilin Medical University, Ji Lin, China
| | - Wei Zhang
- Jilin Medical University, Ji Lin, China
| | - Junjie Xu
- Jilin Medical University, Ji Lin, China
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Plasmodium Genomics and Genetics: New Insights into Malaria Pathogenesis, Drug Resistance, Epidemiology, and Evolution. Clin Microbiol Rev 2019; 32:32/4/e00019-19. [PMID: 31366610 DOI: 10.1128/cmr.00019-19] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Protozoan Plasmodium parasites are the causative agents of malaria, a deadly disease that continues to afflict hundreds of millions of people every year. Infections with malaria parasites can be asymptomatic, with mild or severe symptoms, or fatal, depending on many factors such as parasite virulence and host immune status. Malaria can be treated with various drugs, with artemisinin-based combination therapies (ACTs) being the first-line choice. Recent advances in genetics and genomics of malaria parasites have contributed greatly to our understanding of parasite population dynamics, transmission, drug responses, and pathogenesis. However, knowledge gaps in parasite biology and host-parasite interactions still remain. Parasites resistant to multiple antimalarial drugs have emerged, while advanced clinical trials have shown partial efficacy for one available vaccine. Here we discuss genetic and genomic studies of Plasmodium biology, host-parasite interactions, population structures, mosquito infectivity, antigenic variation, and targets for treatment and immunization. Knowledge from these studies will advance our understanding of malaria pathogenesis, epidemiology, and evolution and will support work to discover and develop new medicines and vaccines.
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35
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Gilson PR, Kumarasingha R, Thompson J, Zhang X, Penington JS, Kalhor R, Bullen HE, Lehane AM, Dans MG, de Koning-Ward TF, Holien JK, Soares da Costa TP, Hulett MD, Buskes MJ, Crabb BS, Kirk K, Papenfuss AT, Cowman AF, Abbott BM. A 4-cyano-3-methylisoquinoline inhibitor of Plasmodium falciparum growth targets the sodium efflux pump PfATP4. Sci Rep 2019; 9:10292. [PMID: 31311978 PMCID: PMC6635429 DOI: 10.1038/s41598-019-46500-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/28/2019] [Indexed: 12/31/2022] Open
Abstract
We developed a novel series of antimalarial compounds based on a 4-cyano-3-methylisoquinoline. Our lead compound MB14 achieved modest inhibition of the growth in vitro of the human malaria parasite, Plasmodium falciparum. To identify its biological target we selected for parasites resistant to MB14. Genome sequencing revealed that all resistant parasites bore a single point S374R mutation in the sodium (Na+) efflux transporter PfATP4. There are many compounds known to inhibit PfATP4 and some are under preclinical development. MB14 was shown to inhibit Na+ dependent ATPase activity in parasite membranes, consistent with the compound targeting PfATP4 directly. PfATP4 inhibitors cause swelling and lysis of infected erythrocytes, attributed to the accumulation of Na+ inside the intracellular parasites and the resultant parasite swelling. We show here that inhibitor-induced lysis of infected erythrocytes is dependent upon the parasite protein RhopH2, a component of the new permeability pathways that are induced by the parasite in the erythrocyte membrane. These pathways mediate the influx of Na+ into the infected erythrocyte and their suppression via RhopH2 knockdown limits the accumulation of Na+ within the parasite hence protecting the infected erythrocyte from lysis. This study reveals a role for the parasite-induced new permeability pathways in the mechanism of action of PfATP4 inhibitors.
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Affiliation(s)
- Paul R Gilson
- Burnet Institute, Melbourne, Victoria, 3004, Australia. .,Monash University, Melbourne, Victoria, 3800, Australia.
| | | | - Jennifer Thompson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia
| | - Xinxin Zhang
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | | | - Robabeh Kalhor
- La Trobe University, Melbourne, Victoria, 3086, Australia
| | | | - Adele M Lehane
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Madeline G Dans
- Burnet Institute, Melbourne, Victoria, 3004, Australia.,School of Medicine, Deakin University, Waurn Ponds, Victoria, 3216, Australia
| | | | - Jessica K Holien
- St. Vincent's Institute of Medical Research, Melbourne, Victoria, 3065, Australia
| | | | - Mark D Hulett
- La Trobe University, Melbourne, Victoria, 3086, Australia
| | | | - Brendan S Crabb
- Burnet Institute, Melbourne, Victoria, 3004, Australia.,Monash University, Melbourne, Victoria, 3800, Australia.,University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Kiaran Kirk
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Anthony T Papenfuss
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,University of Melbourne, Melbourne, Victoria, 3010, Australia
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36
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Mutations in Plasmodium falciparum actin-binding protein coronin confer reduced artemisinin susceptibility. Proc Natl Acad Sci U S A 2018; 115:12799-12804. [PMID: 30420498 PMCID: PMC6294886 DOI: 10.1073/pnas.1812317115] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The spread of Plasmodium falciparum with reduced susceptibility to artemisinin (ART) in Southeast Asia threatens global malaria control. Most failures of ART treatment are attributed to mutations in the pfkelch13 locus acting through an unclear mechanism. The role of pfkelch13 in reducing ART susceptibility was first identified in an in vitro selection experiment. We carried out a similar in vitro selection and discovered mutations in a different gene that reduce susceptibility to ART. The gene encodes PfCoronin, a conserved protein that in other organisms binds with actin to enhance cytoskeletal plasticity or is involved in vesicular transport. PfCoronin and PfKelch13 share structural similarities, and this finding may yield insights into the molecular mechanisms of ART resistance. Drug resistance is an obstacle to global malaria control, as evidenced by the recent emergence and rapid spread of delayed artemisinin (ART) clearance by mutant forms of the PfKelch13 protein in Southeast Asia. Identifying genetic determinants of ART resistance in African-derived parasites is important for surveillance and for understanding the mechanism of resistance. In this study, we carried out long-term in vitro selection of two recently isolated West African parasites (from Pikine and Thiès, Senegal) with increasing concentrations of dihydroartemisinin (DHA), the biologically active form of ART, over a 4-y period. We isolated two parasite clones, one from each original isolate, that exhibited enhanced survival to DHA in the ring-stage survival assay. Whole-genome sequence analysis identified 10 mutations in seven different genes. We chose to focus on the gene encoding PfCoronin, a member of the WD40-propeller domain protein family, because mutations in this gene occurred in both independent selections, and the protein shares the β-propeller motif with PfKelch13 protein. For functional validation, when pfcoronin mutations were introduced into the parental parasites by CRISPR/Cas9-mediated gene editing, these mutations were sufficient to reduce ART susceptibility in the parental lines. The discovery of a second gene for ART resistance may yield insights into the molecular mechanisms of resistance. It also suggests that pfcoronin mutants could emerge as a nonkelch13 type of resistance to ART in natural settings.
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37
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Breglio KF, Amato R, Eastman R, Lim P, Sa JM, Guha R, Ganesan S, Dorward DW, Klumpp-Thomas C, McKnight C, Fairhurst RM, Roberts D, Thomas C, Simon AK. A single nucleotide polymorphism in the Plasmodium falciparum atg18 gene associates with artemisinin resistance and confers enhanced parasite survival under nutrient deprivation. Malar J 2018; 17:391. [PMID: 30367653 PMCID: PMC6204056 DOI: 10.1186/s12936-018-2532-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 10/17/2018] [Indexed: 01/20/2023] Open
Abstract
Background Artemisinin-resistant Plasmodium falciparum has been reported throughout the Greater Mekong subregion and threatens to disrupt current malaria control efforts worldwide. Polymorphisms in kelch13 have been associated with clinical and in vitro resistance phenotypes; however, several studies suggest that the genetic determinants of resistance may involve multiple genes. Current proposed mechanisms of resistance conferred by polymorphisms in kelch13 hint at a connection to an autophagy-like pathway in P. falciparum. Results A SNP in autophagy-related gene 18 (atg18) was associated with long parasite clearance half-life in patients following artemisinin-based combination therapy. This gene encodes PfAtg18, which is shown to be similar to the mammalian/yeast homologue WIPI/Atg18 in terms of structure, binding abilities, and ability to form puncta in response to stress. To investigate the contribution of this polymorphism, the atg18 gene was edited using CRISPR/Cas9 to introduce a T38I mutation into a k13-edited Dd2 parasite. The presence of this SNP confers a fitness advantage by enabling parasites to grow faster in nutrient-limited settings. The mutant and parent parasites were screened against drug libraries of 6349 unique compounds. While the SNP did not modulate the parasite’s susceptibility to any of the anti-malarial compounds using a 72-h drug pulse, it did alter the parasite’s susceptibility to 227 other compounds. Conclusions These results suggest that the atg18 T38I polymorphism may provide additional resistance against artemisinin derivatives, but not partner drugs, even in the absence of kelch13 mutations, and may also be important in parasite survival during nutrient deprivation. Electronic supplementary material The online version of this article (10.1186/s12936-018-2532-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kimberly F Breglio
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA. .,Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Roberto Amato
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Richard Eastman
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Pharath Lim
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Juliana M Sa
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Rajarshi Guha
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA.,Vertex Pharmaceuticals, Boston, MA, USA
| | - Sundar Ganesan
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - David W Dorward
- Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Carleen Klumpp-Thomas
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Crystal McKnight
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Rick M Fairhurst
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - David Roberts
- Radcliffe Department of Medicine, Medical Sciences Division, University of Oxford, Oxford, UK
| | - Craig Thomas
- National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD, USA
| | - Anna Katharina Simon
- Kennedy Institute of Rheumatology and Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
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Duffy S, Avery VM. Routine In Vitro Culture of Plasmodium falciparum: Experimental Consequences? Trends Parasitol 2018; 34:564-575. [DOI: 10.1016/j.pt.2018.04.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 04/20/2018] [Accepted: 04/23/2018] [Indexed: 12/20/2022]
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Rocamora F, Zhu L, Liong KY, Dondorp A, Miotto O, Mok S, Bozdech Z. Oxidative stress and protein damage responses mediate artemisinin resistance in malaria parasites. PLoS Pathog 2018; 14:e1006930. [PMID: 29538461 PMCID: PMC5868857 DOI: 10.1371/journal.ppat.1006930] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 03/26/2018] [Accepted: 02/08/2018] [Indexed: 12/16/2022] Open
Abstract
Due to their remarkable parasitocidal activity, artemisinins represent the key components of first-line therapies against Plasmodium falciparum malaria. However, the decline in efficacy of artemisinin-based drugs jeopardizes global efforts to control and ultimately eradicate the disease. To better understand the resistance phenotype, artemisinin-resistant parasite lines were derived from two clones of the 3D7 strain of P. falciparum using a selection regimen that mimics how parasites interact with the drug within patients. This long term in vitro selection induced profound stage-specific resistance to artemisinin and its relative compounds. Chemosensitivity and transcriptional profiling of artemisinin-resistant parasites indicate that enhanced adaptive responses against oxidative stress and protein damage are associated with decreased artemisinin susceptibility. This corroborates our previous findings implicating these cellular functions in artemisinin resistance in natural infections. Genomic characterization of the two derived parasite lines revealed a spectrum of sequence and copy number polymorphisms that could play a role in regulating artemisinin response, but did not include mutations in pfk13, the main marker of artemisinin resistance in Southeast Asia. Taken together, here we present a functional in vitro model of artemisinin resistance that is underlined by a new set of genetic polymorphisms as potential genetic markers.
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Affiliation(s)
- Frances Rocamora
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Lei Zhu
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Kek Yee Liong
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Arjen Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Olivo Miotto
- Medical Research Council (MRC) Centre for Genomics and Global Health, University of Oxford, Oxford, United Kingdom
| | - Sachel Mok
- Columbia University Medical Center, New York, New York, United States of America
| | - Zbynek Bozdech
- School of Biological Sciences, Nanyang Technological University, Singapore
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40
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Zhang J, Feng GH, Zou CY, Su PC, Liu HE, Yang ZQ. Overview of the improvement of the ring-stage survival assay-a novel phenotypic assay for the detection of artemisinin-resistant Plasmodium falciparum. Zool Res 2018; 38:317-320. [PMID: 29280362 PMCID: PMC5767555 DOI: 10.24272/j.issn.2095-8137.2017.075] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Artemisinin resistance in Plasmodium falciparum threatens the remarkable efficacy of artemisinin-based combination therapies worldwide. Thus, greater insight into the resistance mechanism using monitoring tools is essential. The ring-stage survival assay is used for phenotyping artemisinin-resistance or decreased artemisinin sensitivity. Here, we review the progress of this measurement assay and explore its limitations and potential applications.
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Affiliation(s)
- Jie Zhang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming Yunnan 650500, China
| | - Guo-Hua Feng
- Biomedical Engineering Research Center, Kunming Medical University, Kunming Yunnan 650500, China
| | - Chun-Yan Zou
- Guangxi Zhuang Autonomous Region People's Hospital, Nanning Guangxi 530021, China
| | - Pin-Can Su
- Transfusion Medicine Research Department, Yunnan Kunming Blood Center, Kunming Yunnan 650500, China
| | - Huai-E Liu
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming Yunnan 650500, China.,Department of Infectious Diseases, The First Affiliated Hospital, Kunming Medical University, Kunming Yunnan 650032, China
| | - Zhao-Qing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming Yunnan 650500, China.
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41
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Genetic resistance to purine nucleoside phosphorylase inhibition in Plasmodium falciparum. Proc Natl Acad Sci U S A 2018; 115:2114-2119. [PMID: 29440412 DOI: 10.1073/pnas.1525670115] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Plasmodium falciparum causes the most lethal form of human malaria and is a global health concern. The parasite responds to antimalarial therapies by developing drug resistance. The continuous development of new antimalarials with novel mechanisms of action is a priority for drug combination therapies. The use of transition-state analog inhibitors to block essential steps in purine salvage has been proposed as a new antimalarial approach. Mutations that reduce transition-state analog binding are also expected to reduce the essential catalytic function of the target. We have previously reported that inhibition of host and P. falciparum purine nucleoside phosphorylase (PfPNP) by DADMe-Immucillin-G (DADMe-ImmG) causes purine starvation and parasite death in vitro and in primate infection models. P. falciparum cultured under incremental DADMe-ImmG drug pressure initially exhibited increased PfPNP gene copy number and protein expression. At increased drug pressure, additional PfPNP gene copies appeared with point mutations at catalytic site residues involved in drug binding. Mutant PfPNPs from resistant clones demonstrated reduced affinity for DADMe-ImmG, but also reduced catalytic efficiency. The catalytic defects were partially overcome by gene amplification in the region expressing PfPNP. Crystal structures of native and mutated PfPNPs demonstrate altered catalytic site contacts to DADMe-ImmG. Both point mutations and gene amplification are required to overcome purine starvation induced by DADMe-ImmG. Resistance developed slowly, over 136 generations (2136 clonal selection). Transition-state analog inhibitors against PfPNP are slow to induce resistance and may have promise in malaria therapy.
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De Lucia S, Tsamesidis I, Pau MC, Kesely KR, Pantaleo A, Turrini F. Induction of high tolerance to artemisinin by sub-lethal administration: A new in vitro model of P. falciparum. PLoS One 2018; 13:e0191084. [PMID: 29342187 PMCID: PMC5771598 DOI: 10.1371/journal.pone.0191084] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 12/18/2017] [Indexed: 12/13/2022] Open
Abstract
Artemisinin resistance is a major threat to malaria control efforts. Resistance is characterized by an increase in the Plasmodium falciparum parasite clearance half-life following treatment with artemisinin-based combination therapies (ACTs) and an increase in the percentage of surviving parasites. The remarkably short blood half-life of artemisinin derivatives may contribute to drug-resistance, possibly through factors including sub-lethal plasma concentrations and inadequate exposure. Here we selected for a new strain of artemisinin resistant parasites, termed the artemisinin resistant strain 1 (ARS1), by treating P. falciparum Palo Alto (PA) cultures with sub-lethal concentrations of dihydroartemisinin (DHA). The resistance phenotype was maintained for over 1 year through monthly maintenance treatments with low doses of 2.5 nM DHA. There was a moderate increase in the DHA IC50 in ARS1 when compared with parental strain PA after 72 h of drug exposure (from 0.68 nM to 2 nM DHA). In addition, ARS1 survived treatment physiologically relevant DHA concentrations (700 nM) observed in patients. Furthermore, we confirmed a lack of cross-resistance against a panel of antimalarials commonly used as partner drugs in ACTs. Finally, ARS1 did not contain Pfk13 propeller domain mutations associated with ART resistance in the Greater Mekong Region. With a stable growth rate, ARS1 represents a valuable tool for the development of new antimalarial compounds and studies to further elucidate the mechanisms of ART resistance.
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Affiliation(s)
- Serena De Lucia
- Department of Oncology, University of Turin, Turin, Italy
- * E-mail:
| | - Ioannis Tsamesidis
- Department of Medicine, Section of Internal Medicine, University of Verona, Verona, Italy
| | - Maria Carmina Pau
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Kristina R. Kesely
- Department of Biochemistry, Purdue University, West Lafayette, United States of America
| | - Antonella Pantaleo
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
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Abstract
Increasing antimalarial drug resistance once again threatens effective antimalarial drug treatment, malaria control, and elimination. Artemisinin combination therapies (ACTs) are first-line treatment for uncomplicated falciparum malaria in all endemic countries, yet partial resistance to artemisinins has emerged in the Greater Mekong Subregion. Concomitant emergence of partner drug resistance is now causing high ACT treatment failure rates in several areas. Genetic markers for artemisinin resistance and several of the partner drugs have been established, greatly facilitating surveillance. Single point mutations in the gene coding for the Kelch propeller domain of the K13 protein strongly correlate with artemisinin resistance. Novel regimens and strategies using existing antimalarial drugs will be needed until novel compounds can be deployed. Elimination of artemisinin resistance will imply elimination of all falciparum malaria from the same areas. In vivax malaria, chloroquine resistance is an increasing problem.
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Affiliation(s)
- Didier Menard
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh 12201, Cambodia
| | - Arjen Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 73170, Thailand
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Aponte S, Guerra ÁP, Álvarez-Larrotta C, Bernal SD, Restrepo C, González C, Yasnot MF, Knudson-Ospina A. Baseline in vivo, ex vivo and molecular responses of Plasmodium falciparum to artemether and lumefantrine in three endemic zones for malaria in Colombia. Trans R Soc Trop Med Hyg 2017; 111:71-80. [DOI: 10.1093/trstmh/trx021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 04/13/2017] [Indexed: 01/28/2023] Open
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Gil JP, Krishna S. pfmdr1 (Plasmodium falciparum multidrug drug resistance gene 1): a pivotal factor in malaria resistance to artemisinin combination therapies. Expert Rev Anti Infect Ther 2017; 15:527-543. [DOI: 10.1080/14787210.2017.1313703] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- J. Pedro Gil
- Physiology and Pharmacology Department, Karolinska Institutet, Stockholm, Sweden
| | - S. Krishna
- St George’s University Hospital, Institute for Infection and Immunity, London, United Kingdom
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Jovel IT, Björkman A, Roper C, Mårtensson A, Ursing J. Unexpected selections of Plasmodium falciparum polymorphisms in previously treatment-naïve areas after monthly presumptive administration of three different anti-malarial drugs in Liberia 1976-78. Malar J 2017; 16:113. [PMID: 28288632 PMCID: PMC5347173 DOI: 10.1186/s12936-017-1747-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 02/21/2017] [Indexed: 01/08/2023] Open
Abstract
Background To assess the effect on malaria prevalence, village specific monthly administrations of pyrimethamine, chlorproguanil, chloroquine or placebo were given to children in four previously treatment-naïve Liberian villages, 1976–78. Plasmodium falciparum in vivo resistance developed to pyrimethamine only. Selection of molecular markers of P. falciparum resistance after 2 years of treatment are reported. Methods Blood samples were collected from 191 study children in a survey in 1978. Polymorphisms in pfcrt, pfmdr1, pfdhfr, pfdhps, pfmrp1 and pfnhe1 genes were determined using PCR-based methods. Results Pfcrt 72–76 CVIET was found in one chloroquine village sample, all remaining samples had pfcrt CVMNK. Pfmdr1 N86 prevalence was 100%. A pfmdr1 T1069ACT→ACG synonymous polymorphism was found in 30% of chloroquine village samples and 3% of other samples (P = 0.008). Variations in pfnhe1 block I were found in all except the chloroquine treated village (P < 0.001). Resistance associated pfdhfr 108N prevalence was 2% in the pyrimethamine village compared to 45–65% elsewhere, including the placebo village (P = 0.001). Conclusions Chloroquine treatment possibly resulted in the development of pfcrt 72–76 CVIET. Selection of pfmdr1 T1069ACG and a pfnhe1 block 1 genotypes indicates that chloroquine treatment exerted a selective pressure on P. falciparum. Pyrimethamine resistance associated pfdhfr 108N was present prior to the introduction of any drug. Decreased pfdhfr 108N frequency concurrent with development of pyrimethamine resistance suggests a non-pfdhfr polymorphisms mediated resistance mechanism. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1747-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Irina T Jovel
- Malaria Research, Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
| | - Anders Björkman
- Malaria Research, Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Cally Roper
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Andreas Mårtensson
- Department of Women's and Children's Health, International Maternal and Child Health Unit, Uppsala University, Uppsala, Sweden
| | - Johan Ursing
- Malaria Research, Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Department of Infectious Diseases, Danderyds Hospital, Stockholm, Sweden
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Eastman RT, Khine P, Huang R, Thomas CJ, Su XZ. PfCRT and PfMDR1 modulate interactions of artemisinin derivatives and ion channel blockers. Sci Rep 2016; 6:25379. [PMID: 27147113 PMCID: PMC4857081 DOI: 10.1038/srep25379] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/15/2016] [Indexed: 01/01/2023] Open
Abstract
Treatment of the symptomatic asexual stage of Plasmodium falciparum relies almost exclusively on artemisinin (ART) combination therapies (ACTs) in endemic regions. ACTs combine ART or its derivative with a long-acting partner drug to maximize efficacy during the typical three-day regimen. Both laboratory and clinical studies have previously demonstrated that the common drug resistance determinants P. falciparum chloroquine resistance transporter (PfCRT) and multidrug resistance transporter (PfMDR1) can modulate the susceptibility to many current antimalarial drugs and chemical compounds. Here we investigated the parasite responses to dihydroartemisinin (DHA) and various Ca2+ and Na+ channel blockers and showed positively correlated responses between DHA and several channel blockers, suggesting potential shared transport pathways or mode of action. Additionally, we demonstrated that PfCRT and PfMDR1 could also significantly modulate the pharmacodynamic interactions of the compounds and that the interactions were influenced by the parasite genetic backgrounds. These results provide important information for better understanding of drug resistance and for assessing the overall impact of drug resistance markers on parasite response to ACTs.
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Affiliation(s)
- Richard T Eastman
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA.,Division of Preclinical Development, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, USA
| | - Pwint Khine
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Ruili Huang
- Division of Preclinical Development, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, USA
| | - Craig J Thomas
- Division of Preclinical Development, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, USA
| | - Xin-Zhuan Su
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
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In Vivo Efficacy of Artesunate/Sulphadoxine-Pyrimethamine versus Artesunate/Amodiaquine in the Treatment of Uncomplicated P. falciparium Malaria in Children around the Slope of Mount Cameroon: A Randomized Controlled Trial. Biomedicines 2016; 4:biomedicines4010005. [PMID: 28536372 PMCID: PMC5344242 DOI: 10.3390/biomedicines4010005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 01/31/2016] [Accepted: 02/04/2016] [Indexed: 11/21/2022] Open
Abstract
Background: The development and spread of antimalarial drug resistant parasites contributes to the global impact of the disease. In vivo efficacy assessments of treatments for Plasmodium falciparum malaria are essential for ensuring effective case management. Artemisinin-based combinations have been adopted as the first-line treatment for uncomplicated P. falciparum malaria in Cameroon since 2004. Methods: A total of 177 children aged six-months to 10 years with uncomplicated mono-infected falciparum malaria were randomized (1:1) to receive artesunate/sulphadoxine-pyrimethamine (AS/SP) or artesunate/amodiaquine (AS/AQ) pediatric tablets and followed up for 28 days according to the standard World Health Organization in vivo drug efficacy monitoring protocol. The primary and secondary endpoints were PCR uncorrected and corrected cure rates, as measured by adequate clinical and parasitological response (ACPR) on day 28. Results: The PCR corrected cure rate was high, overall (88.1%, 95% CI 83.1–93.1), 85.9% (95% CI 78.2–93.6), and 90.2% (95% CI 83.8–96.6) for AS/SP and AS/AQ, respectively. Twenty-one treatment failures were observed during follow-up, constituting one (4.6%), 14 (8.2%), and six (3.5%) early treatment failure (ETF), late clinical failure (LCF), and late parasitological failure (LPF), respectively. The drugs were well tolerated with no serious adverse events. Conclusions: Both AS/SP and AS/AQ are highly effective and well-tolerated treatments for uncomplicated P. falciparum malaria around the slope of Mount Cameroon.
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Amoah LE, Kakaney C, Kwansa-Bentum B, Kusi KA. Activity of Herbal Medicines on Plasmodium falciparum Gametocytes: Implications for Malaria Transmission in Ghana. PLoS One 2015; 10:e0142587. [PMID: 26562778 PMCID: PMC4642932 DOI: 10.1371/journal.pone.0142587] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 10/23/2015] [Indexed: 12/17/2022] Open
Abstract
Background Malaria still remains a major health issue in Ghana despite the introduction of Artemisinin-based combination therapy (ACT) coupled with other preventative measures such as the use of insecticide treated nets (ITNs). The global quest for eradication of malaria has heightened the interest of identifying drugs that target the sexual stage of the parasite, referred to as transmission-blocking drugs. This study aimed at assessing the efficacy and gametocydal effects of some commonly used herbal malaria products in Ghana. Methodology/Principal Findings After identifying herbal anti-malarial products frequently purchased on the Ghanaian market, ten of them were selected and lyophilized. In vitro drug sensitivity testing of different concentrations of the herbal products was carried out on asexual and in vitro generated gametocytes of the 3D7 strain of Plasmodium falciparum. The efficacies of the products were assessed by microscopy. Cultures containing low dose of RT also produced the least number of late stage gametocytes. Two of the herbal products CM and RT inhibited the growth of late stage gametocytes by > 80% at 100 μg/ml whilst KG was the most inhibitory to early stage gametocytes at that same concentration. However at 1 μg/ml, only YF significantly inhibited the survival of late stage gametocytes although at that same concentration YF barely inhibited the survival of early stage gametocytes. Conclusions/Significance Herbal product RT (Aloe schweinfurthii, Khaya senegalensis, Piliostigma thonningii and Cassia siamea) demonstrated properties of a highly efficacious gametocydal product. Low dose of herbal product RT exhibited the highest gametocydal activity and at 100 μg/ml, RT exhibited >80% inhibition of late stage gametocytes. However inhibition of asexual stage parasite by RT was not optimal. Improving the asexual inhibition of RT could convert RT into an ideal antimalarial herbal product. We also found that generally C. sanguinolenta containing herbal products exhibited gametocydal activity in addition to high asexual efficacy. Herbal products with high gametocydal activity can help in the fight to reduce malaria transmission.
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Affiliation(s)
- Linda Eva Amoah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Courage Kakaney
- Department of Animal Biology and Conservation Science, College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
| | - Bethel Kwansa-Bentum
- Department of Animal Biology and Conservation Science, College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
| | - Kwadwo Asamoah Kusi
- Department of Immunology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
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Mita T, Tachibana SI, Hashimoto M, Hirai M. Plasmodium falciparum kelch 13: a potential molecular marker for tackling artemisinin-resistant malaria parasites. Expert Rev Anti Infect Ther 2015; 14:125-35. [PMID: 26535806 DOI: 10.1586/14787210.2016.1106938] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Although artemisinin combination therapies have been deployed as a first-line treatment for uncomplicated malaria in almost all endemic countries, artemisinin-resistant parasites have emerged and have gradually spread across the Greater Mekong subregions. There is growing concern that the resistant parasites may migrate to or emerge indigenously in sub-Saharan Africa, which might provoke a global increase in malaria-associated morbidity and mortality. Therefore, development of molecular markers that enable identification of artemisinin resistance with high sensitivity is urgently required to combat this issue. In 2014, a potential artemisinin-resistance responsible gene, Plasmodium falciparum kelch13, was discovered. Here, we review the genetic features of P. falciparum kelch13 and discuss its related resistant mechanisms and potential as a molecular marker.
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Affiliation(s)
- Toshihiro Mita
- a Department of Molecular and Cellular Parasitology , Juntendo University School of Medicine , Tokyo , Japan
| | - Shin-Ichiro Tachibana
- a Department of Molecular and Cellular Parasitology , Juntendo University School of Medicine , Tokyo , Japan
| | - Muneaki Hashimoto
- a Department of Molecular and Cellular Parasitology , Juntendo University School of Medicine , Tokyo , Japan
| | - Makoto Hirai
- a Department of Molecular and Cellular Parasitology , Juntendo University School of Medicine , Tokyo , Japan
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