1
|
Dynamics of DNA Replication during Male Gametogenesis in the Malaria Parasite Plasmodium Falciparum. Cell Microbiol 2022. [DOI: 10.1155/2022/2701868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Malaria parasites undergo a single phase of sexual reproduction in their complex lifecycle. It involves specialised, sexually committed cells called gametocytes, which develop rapidly into mature gametes and mate upon entering the mosquito midgut. Gamete development is unique, involving unprecedentedly fast replication to produce male gametes. Within ~15 minutes a male gametocyte replicates its ~23 Mb genome three times to produce 8 genomes, segregates these into newly-assembled flagellated gametes and releases them to seek female gametes. Here, for the first time, we use fluorescent labelling of de novo DNA synthesis to follow this process at the whole-cell and single-molecule levels. We make several novel observations, including characterising the origin recognition complex protein Orc1 for the first time in gametocytes, finding that cytokinesis is uncoupled from DNA replication (implying a lack of cell cycle checkpoints), and that the single-molecule dynamics of DNA replication are entirely different from the dynamics in asexual schizogony.
Collapse
|
2
|
Reader J, van der Watt ME, Birkholtz LM. Streamlined and Robust Stage-Specific Profiling of Gametocytocidal Compounds Against Plasmodium falciparum. Front Cell Infect Microbiol 2022; 12:926460. [PMID: 35846744 PMCID: PMC9282888 DOI: 10.3389/fcimb.2022.926460] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/30/2022] [Indexed: 12/29/2022] Open
Abstract
Malaria elimination is dependent on the ability to target both the pathogenic and transmissible stages of the human malaria parasite, Plasmodium falciparum. These forms of the parasite are differentiated by unique developmental stages, each with their own biological mechanisms and processes. These individual stages therefore also respond differently to inhibitory compounds, and this complicates the discovery of multistage active antimalarial agents. The search for compounds with transmission-blocking activity has focused on screening for activity on mature gametocytes, with only limited descriptions available for the activity of such compounds on immature stage gametocytes. This therefore poses a gap in the profiling of antimalarial agents for pan-reactive, multistage activity to antimalarial leads. Here, we optimized an effective and robust strategy for the simple and cost-effective description of the stage-specific action of gametocytocidal antimalarial compounds.
Collapse
Affiliation(s)
- Janette Reader
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Mariette E. van der Watt
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - Lyn-Marié Birkholtz
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- *Correspondence: Lyn-Marié Birkholtz,
| |
Collapse
|
3
|
van der Watt ME, Reader J, Birkholtz LM. Adapt or Die: Targeting Unique Transmission-Stage Biology for Malaria Elimination. Front Cell Infect Microbiol 2022; 12:901971. [PMID: 35755845 PMCID: PMC9218253 DOI: 10.3389/fcimb.2022.901971] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 05/06/2022] [Indexed: 12/25/2022] Open
Abstract
Plasmodium parasites have a complex life cycle that includes development in the human host as well as the Anopheles vector. Successful transmission of the parasite between its host and vector therefore requires the parasite to balance its investments in asexual replication and sexual reproduction, varying the frequency of sexual commitment to persist within the human host and generate future opportunities for transmission. The transmission window is extended further by the ability of stage V gametocytes to circulate in peripheral blood for weeks, whereas immature stage I to IV gametocytes sequester in the bone marrow and spleen until final maturation. Due to the low gametocyte numbers in blood circulation and with the ease of targeting such life cycle bottlenecks, transmission represents an efficient target for therapeutic intervention. The biological process of Plasmodium transmission is a multistage, multifaceted process and the past decade has seen a much deeper understanding of the molecular mechanisms and regulators involved. Clearly, specific and divergent processes are used during transmission compared to asexual proliferation, which both poses challenges but also opportunities for discovery of transmission-blocking antimalarials. This review therefore presents an update of our molecular understanding of gametocyte and gamete biology as well as the status of transmission-blocking activities of current antimalarials and lead development compounds. By defining the biological components associated with transmission, considerations for the development of new transmission-blocking drugs to target such untapped but unique biology is suggested as an important, main driver for transmission-blocking drug discovery.
Collapse
Affiliation(s)
- Mariëtte E van der Watt
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - Janette Reader
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa.,Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Lyn-Marié Birkholtz
- Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa.,Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| |
Collapse
|
4
|
Connacher J, von Grüning H, Birkholtz L. Histone Modification Landscapes as a Roadmap for Malaria Parasite Development. Front Cell Dev Biol 2022; 10:848797. [PMID: 35433676 PMCID: PMC9010790 DOI: 10.3389/fcell.2022.848797] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 03/04/2022] [Indexed: 12/26/2022] Open
Abstract
Plasmodium falciparum remains the deadliest parasite species in the world, responsible for 229 million cases of human malaria in 2019. The ability of the P. falciparum parasite to progress through multiple life cycle stages and thrive in diverse host and vector species hinges on sophisticated mechanisms of epigenetic regulation of gene expression. Emerging evidence indicates such epigenetic control exists in concentric layers, revolving around core histone post-translational modification (PTM) landscapes. Here, we provide a necessary update of recent epigenome research in malaria parasites, focusing specifically on the ability of dynamic histone PTM landscapes to orchestrate the divergent development and differentiation pathways in P. falciparum parasites. In addition to individual histone PTMs, we discuss recent findings that imply functional importance for combinatorial PTMs in P. falciparum parasites, representing an operational histone code. Finally, this review highlights the remaining gaps and provides strategies to address these to obtain a more thorough understanding of the histone modification landscapes that are at the center of epigenetic regulation in human malaria parasites.
Collapse
|
5
|
Birkholtz LM, Alano P, Leroy D. Transmission-blocking drugs for malaria elimination. Trends Parasitol 2022; 38:390-403. [DOI: 10.1016/j.pt.2022.01.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 01/19/2022] [Accepted: 01/24/2022] [Indexed: 12/24/2022]
|
6
|
van Heerden A, van Wyk R, Birkholtz LM. Machine Learning Uses Chemo-Transcriptomic Profiles to Stratify Antimalarial Compounds With Similar Mode of Action. Front Cell Infect Microbiol 2021; 11:688256. [PMID: 34268139 PMCID: PMC8277430 DOI: 10.3389/fcimb.2021.688256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/04/2021] [Indexed: 11/26/2022] Open
Abstract
The rapid development of antimalarial resistance motivates the continued search for novel compounds with a mode of action (MoA) different to current antimalarials. Phenotypic screening has delivered thousands of promising hit compounds without prior knowledge of the compounds’ exact target or MoA. Whilst the latter is not initially required to progress a compound in a medicinal chemistry program, identifying the MoA early can accelerate hit prioritization, hit-to-lead optimization and preclinical combination studies in malaria research. The effects of drug treatment on a cell can be observed on systems level in changes in the transcriptome, proteome and metabolome. Machine learning (ML) algorithms are powerful tools able to deconvolute such complex chemically-induced transcriptional signatures to identify pathways on which a compound act and in this manner provide an indication of the MoA of a compound. In this study, we assessed different ML approaches for their ability to stratify antimalarial compounds based on varied chemically-induced transcriptional responses. We developed a rational gene selection approach that could identify predictive features for MoA to train and generate ML models. The best performing model could stratify compounds with similar MoA with a classification accuracy of 76.6 ± 6.4%. Moreover, only a limited set of 50 biomarkers was required to stratify compounds with similar MoA and define chemo-transcriptomic fingerprints for each compound. These fingerprints were unique for each compound and compounds with similar targets/MoA clustered together. The ML model was specific and sensitive enough to group new compounds into MoAs associated with their predicted target and was robust enough to be extended to also generate chemo-transcriptomic fingerprints for additional life cycle stages like immature gametocytes. This work therefore contributes a new strategy to rapidly, specifically and sensitively indicate the MoA of compounds based on chemo-transcriptomic fingerprints and holds promise to accelerate antimalarial drug discovery programs.
Collapse
Affiliation(s)
- Ashleigh van Heerden
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield, South Africa.,University of Pretoria Institute for Sustainable Malaria Control, University of Pretoria, Hatfield, South Africa
| | - Roelof van Wyk
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield, South Africa.,University of Pretoria Institute for Sustainable Malaria Control, University of Pretoria, Hatfield, South Africa
| | - Lyn-Marie Birkholtz
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield, South Africa.,University of Pretoria Institute for Sustainable Malaria Control, University of Pretoria, Hatfield, South Africa
| |
Collapse
|
7
|
Connacher J, Josling GA, Orchard LM, Reader J, Llinás M, Birkholtz LM. H3K36 methylation reprograms gene expression to drive early gametocyte development in Plasmodium falciparum. Epigenetics Chromatin 2021; 14:19. [PMID: 33794978 PMCID: PMC8017609 DOI: 10.1186/s13072-021-00393-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/26/2021] [Indexed: 12/12/2022] Open
Abstract
Background The Plasmodium sexual gametocyte stages are the only transmissible form of the malaria parasite and are thus responsible for the continued transmission of the disease. Gametocytes undergo extensive functional and morphological changes from commitment to maturity, directed by an equally extensive control program. However, the processes that drive the differentiation and development of the gametocyte post-commitment, remain largely unexplored. A previous study reported enrichment of H3K36 di- and tri-methylated (H3K36me2&3) histones in early-stage gametocytes. Using chromatin immunoprecipitation followed by high-throughput sequencing, we identify a stage-specific association between these repressive histone modifications and transcriptional reprogramming that define a stage II gametocyte transition point. Results Here, we show that H3K36me2 and H3K36me3 from stage II gametocytes are associated with repression of genes involved in asexual proliferation and sexual commitment, indicating that H3K36me2&3-mediated repression of such genes is essential to the transition from early gametocyte differentiation to intermediate development. Importantly, we show that the gene encoding the transcription factor AP2-G as commitment master regulator is enriched with H3K36me2&3 and actively repressed in stage II gametocytes, providing the first evidence of ap2-g gene repression in post-commitment gametocytes. Lastly, we associate the enhanced potency of the pan-selective Jumonji inhibitor JIB-04 in gametocytes with the inhibition of histone demethylation including H3K36me2&3 and a disruption of normal transcriptional programs. Conclusions Taken together, our results provide the first description of an association between global gene expression reprogramming and histone post-translational modifications during P. falciparum early sexual development. The stage II gametocyte-specific abundance of H3K36me2&3 manifests predominantly as an independent regulatory mechanism targeted towards genes that are repressed post-commitment. H3K36me2&3-associated repression of genes is therefore involved in key transcriptional shifts that accompany the transition from early gametocyte differentiation to intermediate development. Supplementary Information The online version contains supplementary material available at 10.1186/s13072-021-00393-9.
Collapse
Affiliation(s)
- Jessica Connacher
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Gabrielle A Josling
- Department of Biochemistry & Molecular Biology and the Huck Center for Malaria Research, Pennsylvania State University, University Park, PA, 16802, USA
| | - Lindsey M Orchard
- Department of Biochemistry & Molecular Biology and the Huck Center for Malaria Research, Pennsylvania State University, University Park, PA, 16802, USA
| | - Janette Reader
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa
| | - Manuel Llinás
- Department of Biochemistry & Molecular Biology and the Huck Center for Malaria Research, Pennsylvania State University, University Park, PA, 16802, USA.,Department of Chemistry, Pennsylvania State University, University Park, PA, 16802, USA
| | - Lyn-Marié Birkholtz
- Department of Biochemistry, Genetics and Microbiology, Institute for Sustainable Malaria Control, University of Pretoria, Private Bag x20, Hatfield, 0028, South Africa.
| |
Collapse
|
8
|
Multistage and transmission-blocking targeted antimalarials discovered from the open-source MMV Pandemic Response Box. Nat Commun 2021; 12:269. [PMID: 33431834 PMCID: PMC7801607 DOI: 10.1038/s41467-020-20629-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 12/10/2020] [Indexed: 12/30/2022] Open
Abstract
Chemical matter is needed to target the divergent biology associated with the different life cycle stages of Plasmodium. Here, we report the parallel de novo screening of the Medicines for Malaria Venture (MMV) Pandemic Response Box against Plasmodium asexual and liver stage parasites, stage IV/V gametocytes, gametes, oocysts and as endectocides. Unique chemotypes were identified with both multistage activity or stage-specific activity, including structurally diverse gametocyte-targeted compounds with potent transmission-blocking activity, such as the JmjC inhibitor ML324 and the antitubercular clinical candidate SQ109. Mechanistic investigations prove that ML324 prevents histone demethylation, resulting in aberrant gene expression and death in gametocytes. Moreover, the selection of parasites resistant to SQ109 implicates the druggable V-type H+-ATPase for the reduced sensitivity. Our data therefore provides an expansive dataset of compounds that could be redirected for antimalarial development and also point towards proteins that can be targeted in multiple parasite life cycle stages. Here, Reader et al. screen the Medicines for Malaria Venture Pandemic Response Box in parallel against Plasmodiumasexual and liver stage parasites, stage IV/V gametocytes, gametes, oocysts and as endectocides. They identify two potent transmission-blocking drugs: a histone demethylase inhibitor ML324 and the antitubercular SQ109.
Collapse
|
9
|
Biosca A, Dirscherl L, Moles E, Imperial S, Fernàndez-Busquets X. An ImmunoPEGliposome for Targeted Antimalarial Combination Therapy at the Nanoscale. Pharmaceutics 2019; 11:pharmaceutics11070341. [PMID: 31315185 PMCID: PMC6680488 DOI: 10.3390/pharmaceutics11070341] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 06/27/2019] [Accepted: 07/11/2019] [Indexed: 12/15/2022] Open
Abstract
Combination therapies, where two drugs acting through different mechanisms are administered simultaneously, are one of the most efficient approaches currently used to treat malaria infections. However, the different pharmacokinetic profiles often exhibited by the combined drugs tend to decrease treatment efficacy as the compounds are usually eliminated from the circulation at different rates. To circumvent this obstacle, we have engineered an immunoliposomal nanovector encapsulating hydrophilic and lipophilic compounds in its lumen and lipid bilayer, respectively. The antimalarial domiphen bromide has been encapsulated in the liposome membrane with good efficiency, although its high IC50 of ca. 1 µM for living parasites complicates its use as immunoliposomal therapy due to erythrocyte agglutination. The conjugation of antibodies against glycophorin A targeted the nanocarriers to Plasmodium-infected red blood cells and to gametocytes, the sole malaria parasite stage responsible for the transmission from the human to the mosquito vector. The antimalarials pyronaridine and atovaquone, which block the development of gametocytes, have been co-encapsulated in glycophorin A-targeted immunoliposomes. The co-immunoliposomized drugs have activities significantly higher than their free forms when tested in in vitro Plasmodium falciparum cultures: Pyronaridine and atovaquone concentrations that, when encapsulated in immunoliposomes, resulted in a 50% inhibition of parasite growth had no effect on the viability of the pathogen when used as free drugs.
Collapse
Affiliation(s)
- Arnau Biosca
- Barcelona Institute for Global Health (ISGlobal, Hospital Clínic-Universitat de Barcelona), Rosselló 149-153, ES-08036 Barcelona, Spain
- Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, ES-08028 Barcelona, Spain
- Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, ES-08028 Barcelona, Spain
| | - Lorin Dirscherl
- Barcelona Institute for Global Health (ISGlobal, Hospital Clínic-Universitat de Barcelona), Rosselló 149-153, ES-08036 Barcelona, Spain
- Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, ES-08028 Barcelona, Spain
- Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, ES-08028 Barcelona, Spain
| | - Ernest Moles
- Children's Cancer Institute, Lowy Cancer Research Centre, UNSW Sydney, PO Box 81, Randwick, NSW 2031, Australia
- School of Women's and Children's Health, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Santiago Imperial
- Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, ES-08028 Barcelona, Spain
- Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Avda. Diagonal 643, ES-08028 Barcelona, Spain
| | - Xavier Fernàndez-Busquets
- Barcelona Institute for Global Health (ISGlobal, Hospital Clínic-Universitat de Barcelona), Rosselló 149-153, ES-08036 Barcelona, Spain.
- Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, ES-08028 Barcelona, Spain.
- Nanoscience and Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, ES-08028 Barcelona, Spain.
| |
Collapse
|
10
|
Abstract
The last two decades have seen a surge in antimalarial drug development with product development partnerships taking a leading role. Resistance of Plasmodium falciparum to the artemisinin derivatives, piperaquine and mefloquine in Southeast Asia means new antimalarials are needed with some urgency. There are at least 13 agents in clinical development. Most of these are blood schizonticides for the treatment of uncomplicated falciparum malaria, under evaluation either singly or as part of two-drug combinations. Leading candidates progressing through the pipeline are artefenomel-ferroquine and lumefantrine-KAF156, both in Phase 2b. Treatment of severe malaria continues to rely on two parenteral drugs with ancient forebears: artesunate and quinine, with sevuparin being evaluated as an adjuvant therapy. Tafenoquine is under review by stringent regulatory authorities for approval as a single-dose treatment for Plasmodium vivax relapse prevention. This represents an advance over standard 14-day primaquine regimens; however, the risk of acute haemolytic anaemia in patients with glucose-6-phosphate dehydrogenase deficiency remains. For disease prevention, several of the newer agents show potential but are unlikely to be recommended for use in the main target groups of pregnant women and young children for some years. Latest predictions are that the malaria burden will continue to be high in the coming decades. This fact, coupled with the repeated loss of antimalarials to resistance, indicates that new antimalarials will be needed for years to come. Failure of the artemisinin-based combinations in Southeast Asia has stimulated a reappraisal of current approaches to combination therapy for malaria with incorporation of three or more drugs in a single treatment under consideration.
Collapse
Affiliation(s)
- Elizabeth A Ashley
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar.
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK.
| | | |
Collapse
|
11
|
Leba LJ, Popovici J, Estevez Y, Pelleau S, Legrand E, Musset L, Duplais C. Antiplasmodial activities of dyes against Plasmodium falciparum asexual and sexual stages: Contrasted uptakes of triarylmethanes Brilliant green, Green S (E142), and Patent Blue V (E131) by erythrocytes. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2017; 7:314-320. [PMID: 28886443 PMCID: PMC5587875 DOI: 10.1016/j.ijpddr.2017.07.002] [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: 02/16/2017] [Revised: 07/27/2017] [Accepted: 07/31/2017] [Indexed: 11/07/2022]
Abstract
The search for safe antimalarial compounds acting against asexual symptom-responsible stages and sexual transmission-responsible forms of Plasmodium species is one of the major challenges in malaria elimination programs. So far, among current drugs approved for human use, only primaquine has transmission-blocking activity. The discovery of small molecules targeting different Plasmodium falciparum life stages remains a priority in antimalarial drug research. In this context, several independent studies have recently reported antiplasmodial and transmission-blocking activities of commonly used stains, dyes and fluorescent probes against P. falciparum including chloroquine-resistant isolates. Herein we have studied the antimalarial activities of dyes with different scaffold and we report that the triarylmethane dye (TRAM) Brilliant green inhibits the growth of asexual stages (IC50 ≤ 2 μM) and has exflagellation-blocking activity (IC50 ≤ 800 nM) against P. falciparum reference strains (3D7, 7G8) and chloroquine-resistant clinical isolate (Q206). In a second step we have investigated the antiplasmodial activities of two polysulfonated triarylmethane food dyes. Green S (E142) is weakly active against P. falciparum asexual stage (IC50 ≃ 17 μM) whereas Patent Blue V (E131) is inactive in both antimalarial assays. By applying liquid chromatography techniques for the culture supernatant analysis after cell washings and lysis, we report the detection of Brilliant green in erythrocytes, the selective uptake of Green S (E142) by infected erythrocytes, whereas Patent Blue V (E131) could not be detected within non-infected and 3D7-infected erythrocytes. Overall, our results suggest that two polysulfonated food dyes might display different affinity with transporters or channels on infected RBC membrane. Dyes are tested against P. falciparum 3D7, 7G8 lines, CQ-resistant field isolate Q206. Brilliant green is active against asexual and sexual stages of Plasmodium falciparum. Food dye Green S (E142) is weakly active against Plasmodium falciparum asexual forms. Food dye Green S (E142) is found in the cellular content of infected erythrocytes. Polysulfonated triarylmethane possibly interact with plasmodial surface anion channel.
Collapse
Affiliation(s)
- Louis-Jérôme Leba
- Laboratoire de parasitologie, CNR du paludisme, Institut Pasteur de la Guyane, Cayenne, French Guiana, France; UMR QualiSud, Université de Guyane, 97300 Cayenne, France
| | - Jean Popovici
- Malaria Molecular Epidemiology Unit, Institut Pasteur in Cambodia, Phnom Penh, Cambodia
| | - Yannick Estevez
- CNRS, UMR8172 EcoFoG, AgroParisTech, Cirad, INRA, Université des Antilles, Université de Guyane, 97300 Cayenne, French Guiana, France
| | - Stéphane Pelleau
- Laboratoire de parasitologie, CNR du paludisme, Institut Pasteur de la Guyane, Cayenne, French Guiana, France
| | - Eric Legrand
- Laboratoire de parasitologie, CNR du paludisme, Institut Pasteur de la Guyane, Cayenne, French Guiana, France; Research Unit of Genetics and Genomics of Insect Vectors Institut Pasteur, Paris, France
| | - Lise Musset
- Laboratoire de parasitologie, CNR du paludisme, Institut Pasteur de la Guyane, Cayenne, French Guiana, France
| | - Christophe Duplais
- CNRS, UMR8172 EcoFoG, AgroParisTech, Cirad, INRA, Université des Antilles, Université de Guyane, 97300 Cayenne, French Guiana, France.
| |
Collapse
|
12
|
Urbán P, Ranucci E, Fernàndez-Busquets X. Polyamidoamine nanoparticles as nanocarriers for the drug delivery to malaria parasite stages in the mosquito vector. Nanomedicine (Lond) 2016; 10:3401-14. [PMID: 26582279 DOI: 10.2217/nnm.15.174] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Malaria is arguably one of the main medical concerns worldwide because of the numbers of people affected, the severity of the disease and the complexity of the life cycle of its causative agent, the protist Plasmodium spp. With the advent of nanoscience, renewed hopes have appeared of finally obtaining the long sought-after magic bullet against malaria in the form of a nanovector for the targeted delivery of antimalarial compounds exclusively to Plasmodium-infected cells, thus increasing drug efficacy and minimizing the induction of resistance to newly developed therapeutic agents. Polyamidoamine-derived nanovectors combine into a single chemical structure drug encapsulating capacity, antimalarial activity, low unspecific toxicity, specific targeting to Plasmodium, optimal in vivo activity and affordable synthesis cost. After having shown their efficacy in targeting drugs to intraerythrocytic parasites, now polyamidoamines face the challenge of spearheading a new generation of nanocarriers aiming at the malaria parasite stages in the mosquito vector.
Collapse
Affiliation(s)
- Patricia Urbán
- European Commission, Joint Research Centre, Institute for Health & Consumer Protection, via E. Fermi 2749, IT-21027, Ispra, Varese, Italy
| | - Elisabetta Ranucci
- Dipartimento di Chimica, Università degli Studi di Milano, via Golgi 19, IT-20133 Milano, Italy
| | - Xavier Fernàndez-Busquets
- Nanomalaria Group, Institute for Bioengineering of Catalonia (IBEC), Baldiri Reixac 10-12, ES-08028 Barcelona, Spain.,Barcelona Institute for Global Health (ISGlobal), Barcelona Center for International Health Research (CRESIB, Hospital Clínic-Universitat de Barcelona), Rosselló 149-153, ES-08036 Barcelona, Spain.,Nanoscience & Nanotechnology Institute (IN2UB), University of Barcelona, Martí i Franquès 1, ES-08028 Barcelona, Spain
| |
Collapse
|
13
|
Birkholtz LM, Coetzer TL, Mancama D, Leroy D, Alano P. Discovering New Transmission-Blocking Antimalarial Compounds: Challenges and Opportunities. Trends Parasitol 2016; 32:669-681. [PMID: 27209388 DOI: 10.1016/j.pt.2016.04.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 04/24/2016] [Accepted: 04/26/2016] [Indexed: 01/08/2023]
Abstract
The ability to target human-mosquito parasite transmission challenges global malaria elimination. However, it is not obvious what a transmission-blocking drug will look like; should it target only parasite transmission stages; be combined with a partner drug killing the pathogenic asexual stages; or kill both the sexual and asexual blood stages, preferably displaying polypharmacology? The development of transmission-blocking antimalarials requires objective analyses of the current strategies. Here, pertinent issues and questions regarding the target candidate profile of a transmission-blocking compound, and its role in malaria elimination strategies, are highlighted and novel perspectives proposed. The essential role of a test cascade that integrates screening and validation strategies to identify next-generation transmission-blocking antimalarials is emphasised.
Collapse
Affiliation(s)
- Lyn-Marie Birkholtz
- Department of Biochemistry, Centre for Sustainable Malaria Control, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa.
| | - Theresa L Coetzer
- Department of Molecular Medicine and Haematology, Wits Research Institute for Malaria, Faculty of Health Sciences, University of the Witwatersrand, National Health Laboratory Service, Johannesburg, South Africa.
| | - Dalu Mancama
- Department of Biochemistry, Centre for Sustainable Malaria Control, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa; Biosciences, Council for Scientific and Industrial Research, Pretoria, South Africa.
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland.
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie e Immunomediate, Istituto Superiore di Sanità, Rome, Italy.
| |
Collapse
|
14
|
Plouffe DM, Wree M, Du AY, Meister S, Li F, Patra K, Lubar A, Okitsu SL, Flannery EL, Kato N, Tanaseichuk O, Comer E, Zhou B, Kuhen K, Zhou Y, Leroy D, Schreiber SL, Scherer CA, Vinetz J, Winzeler EA. High-Throughput Assay and Discovery of Small Molecules that Interrupt Malaria Transmission. Cell Host Microbe 2015; 19:114-26. [PMID: 26749441 PMCID: PMC4723716 DOI: 10.1016/j.chom.2015.12.001] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 11/13/2015] [Accepted: 12/11/2015] [Indexed: 11/18/2022]
Abstract
Preventing transmission is an important element of malaria control. However, most of the current available methods to assay for malaria transmission blocking are relatively low throughput and cannot be applied to large chemical libraries. We have developed a high-throughput and cost-effective assay, the Saponin-lysis Sexual Stage Assay (SaLSSA), for identifying small molecules with transmission-blocking capacity. SaLSSA analysis of 13,983 unique compounds uncovered that >90% of well-characterized antimalarials, including endoperoxides and 4-aminoquinolines, as well as compounds active against asexual blood stages, lost most of their killing activity when parasites developed into metabolically quiescent stage V gametocytes. On the other hand, we identified compounds with consistent low nanomolar transmission-blocking activity, some of which showed cross-reactivity against asexual blood and liver stages. The data clearly emphasize substantial physiological differences between sexual and asexual parasites and provide a tool and starting points for the discovery and development of transmission-blocking drugs.
Collapse
Affiliation(s)
- David M Plouffe
- The Genomics Institute of the Novartis Research Foundation, 10675 John J. Hopkins Drive, San Diego, CA 92121, USA
| | - Melanie Wree
- Division of Pharmacology and Drug Discovery, Department of Pediatrics, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Alan Y Du
- Division of Pharmacology and Drug Discovery, Department of Pediatrics, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Stephan Meister
- Division of Pharmacology and Drug Discovery, Department of Pediatrics, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Fengwu Li
- Division of Infectious Disease, Department of Medicine, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Kailash Patra
- Division of Infectious Disease, Department of Medicine, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Aristea Lubar
- Division of Infectious Disease, Department of Medicine, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Shinji L Okitsu
- Division of Pharmacology and Drug Discovery, Department of Pediatrics, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Erika L Flannery
- Division of Pharmacology and Drug Discovery, Department of Pediatrics, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Nobutaka Kato
- Broad Institute, 415 Main Street, Cambridge MA 02142
| | - Olga Tanaseichuk
- The Genomics Institute of the Novartis Research Foundation, 10675 John J. Hopkins Drive, San Diego, CA 92121, USA
| | - Eamon Comer
- Broad Institute, 415 Main Street, Cambridge MA 02142
| | - Bin Zhou
- The Genomics Institute of the Novartis Research Foundation, 10675 John J. Hopkins Drive, San Diego, CA 92121, USA
| | - Kelli Kuhen
- The Genomics Institute of the Novartis Research Foundation, 10675 John J. Hopkins Drive, San Diego, CA 92121, USA
| | - Yingyao Zhou
- The Genomics Institute of the Novartis Research Foundation, 10675 John J. Hopkins Drive, San Diego, CA 92121, USA
| | - Didier Leroy
- Medicines for Malaria Venture (MMV), PO Box 1826, 20 Route de Pré-Bois, 1215 Geneva 15, Switzerland
| | - Stuart L Schreiber
- Broad Institute, 415 Main Street, Cambridge MA 02142; Department of Chemistry and Chemical Biology, Harvard University, 7 Cambridge Center, Cambridge, MA 02142, USA
| | | | - Joseph Vinetz
- Division of Infectious Disease, Department of Medicine, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Elizabeth A Winzeler
- Division of Pharmacology and Drug Discovery, Department of Pediatrics, University of California San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093, USA.
| |
Collapse
|
15
|
Val FF, Sampaio VS, Cassera MB, Andrade RT, Tauil PL, Monteiro WM, Lacerda MVG. Plasmodium vivax malaria elimination: should innovative ideas from the past be revisited? Mem Inst Oswaldo Cruz 2015; 109:522-4. [PMID: 25184997 PMCID: PMC4156444 DOI: 10.1590/0074-0276140240] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 07/25/2014] [Indexed: 01/13/2023] Open
Abstract
In the 1950s, the strategy of adding chloroquine to food salt as a prophylaxis
against malaria was considered to be a successful tool. However, with the development
of Plasmodium resistance in the Brazilian Amazon, this control
strategy was abandoned. More than 50 years later, asexual stage resistance can be
avoided by screening for antimalarial drugs that have a selective action against
gametocytes, thus old prophylactic measures can be revisited. The efficacy of the old
methods should be tested as complementary tools for the elimination of malaria.
Collapse
Affiliation(s)
| | | | - Maria Belén Cassera
- Department of Biochemistry, Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA, USA
| | | | - Pedro Luiz Tauil
- Faculdade de Medicina, Universidade de Brasília, Brasília, DF, Brasil
| | | | | |
Collapse
|
16
|
Paaijmans K, Fernàndez-Busquets X. Antimalarial drug delivery to the mosquito: an option worth exploring? Future Microbiol 2015; 9:579-82. [PMID: 24957084 DOI: 10.2217/fmb.14.30] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Krijn Paaijmans
- Barcelona Centre for International Health Research (CRESIB, Hospital Clínic-Universitat de Barcelona), Rosselló 149-153, Barcelona ES-08036, Spain
| | | |
Collapse
|
17
|
Li T, Eappen AG, Richman AM, Billingsley PF, Abebe Y, Li M, Padilla D, Rodriguez-Barraquer I, Sim BKL, Hoffman SL. Robust, reproducible, industrialized, standard membrane feeding assay for assessing the transmission blocking activity of vaccines and drugs against Plasmodium falciparum. Malar J 2015; 14:150. [PMID: 25890243 PMCID: PMC4491417 DOI: 10.1186/s12936-015-0665-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 03/24/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND A vaccine that interrupts malaria transmission (VIMT) would be a valuable tool for malaria control and elimination. One VIMT approach is to identify sexual erythrocytic and mosquito stage antigens of the malaria parasite that induce immune responses targeted at disrupting parasite development in the mosquito. The standard Plasmodium falciparum membrane-feeding assay (SMFA) is used to assess transmission-blocking activity (TBA) of antibodies against candidate immunogens and of drugs targeting the mosquito stages. To develop its P. falciparum sporozoite (SPZ) products, Sanaria has industrialized the production of P. falciparum-infected Anopheles stephensi mosquitoes, incorporating quantitative analyses of oocyst and P. falciparum SPZ infections as part of the manufacturing process. METHODS These capabilities were exploited to develop a robust, reliable, consistent SMFA that was used to assess 188 serum samples from animals immunized with the candidate vaccine immunogen, Pfs25, targeting P. falciparum mosquito stages. Seventy-four independent SMFAs were performed. Infection intensity (number of oocysts/mosquito) and infection prevalence (percentage of mosquitoes infected with oocysts) were compared between mosquitoes fed cultured gametocytes plus normal human O(+) serum (negative control), anti-Pfs25 polyclonal antisera (MRA39 or MRA38, at a final dilution in the blood meal of 1:54 as positive control), and test sera from animals immunized with Pfs25 (at a final dilution in the blood meal of 1:9). RESULTS SMFA negative controls consistently yielded high infection intensity (mean = 46.1 oocysts/midgut, range of positives 3.7-135.6) and infection prevalence (mean = 94.2%, range 71.4-100.0) and in positive controls, infection intensity was reduced by 81.6% (anti-Pfs25 MRA39) and 97.0% (anti-Pfs25 MRA38), and infection prevalence was reduced by 12.9 and 63.5%, respectively. A range of TBAs was detected among the 188 test samples assayed in duplicate. Consistent administration of infectious gametocytes to mosquitoes within and between assays was achieved, and the TBA of anti-Pfs25 control antibodies was highly reproducible. CONCLUSIONS These results demonstrate a robust capacity to perform the SMFA in a medium-to-high throughput format, suitable for assessing large numbers of experimental samples of candidate antibodies or drugs.
Collapse
Affiliation(s)
- Tao Li
- Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA.
| | - Abraham G Eappen
- Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA.
| | - Adam M Richman
- Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA.
| | | | - Yonas Abebe
- Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA.
| | - Minglin Li
- Protein Potential LLC, 9800 Medical Center Drive, Rockville, MD, 20850, USA.
| | - Debbie Padilla
- Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA.
| | - Isabel Rodriguez-Barraquer
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Suite E6003, Baltimore, MD, 21205, USA.
| | - B Kim Lee Sim
- Sanaria Inc., 9800 Medical Center Drive, Rockville, MD, 20850, USA.
- Protein Potential LLC, 9800 Medical Center Drive, Rockville, MD, 20850, USA.
| | | |
Collapse
|
18
|
Isoprenoid precursor biosynthesis is the essential metabolic role of the apicoplast during gametocytogenesis in Plasmodium falciparum. EUKARYOTIC CELL 2014; 14:128-39. [PMID: 25446055 DOI: 10.1128/ec.00198-14] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The malaria parasite harbors a relict plastid called the apicoplast and its discovery opened a new avenue for drug discovery and development due to its unusual, nonmammalian metabolism. The apicoplast is essential during the asexual intraerythrocytic and hepatic stages of the parasite, and there is strong evidence supporting its essential metabolic role during the mosquito stages of the parasite. Supply of the isoprenoid building blocks isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) is the essential metabolic function of the apicoplast during the asexual intraerythrocytic stages. However, the metabolic role of the apicoplast during gametocyte development, the malaria stages transmitted to the mosquito, remains unknown. In this study, we showed that production of IPP for isoprenoid biosynthesis is the essential metabolic function of the apicoplast during gametocytogenesis, by obtaining normal gametocytes lacking the apicoplast when supplemented with IPP. When IPP supplementation was removed early in gametocytogenesis, developmental defects were observed, supporting the essential role of isoprenoids for normal gametocytogenesis. Furthermore, mosquitoes infected with gametocytes lacking the apicoplast developed fewer and smaller oocysts that failed to produce sporozoites. This finding further supports the essential role of the apicoplast in establishing a successful infection in the mosquito vector. Our study supports isoprenoid biosynthesis as a valid drug target for development of malaria transmission-blocking inhibitors.
Collapse
|
19
|
Vidadala RSR, Ojo KK, Johnson SM, Zhang Z, Leonard SE, Mitra A, Choi R, Reid MC, Keyloun KR, Fox AMW, Kennedy M, Silver-Brace T, Hume JCC, Kappe S, Verlinde CLMJ, Fan E, Merritt EA, Van Voorhis WC, Maly DJ. Development of potent and selective Plasmodium falciparum calcium-dependent protein kinase 4 (PfCDPK4) inhibitors that block the transmission of malaria to mosquitoes. Eur J Med Chem 2014; 74:562-73. [PMID: 24531197 DOI: 10.1016/j.ejmech.2013.12.048] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 12/23/2013] [Accepted: 12/26/2013] [Indexed: 12/16/2022]
Abstract
Malaria remains a major health concern for a large percentage of the world's population. While great strides have been made in reducing mortality due to malaria, new strategies and therapies are still needed. Therapies that are capable of blocking the transmission of Plasmodium parasites are particularly attractive, but only primaquine accomplishes this, and toxicity issues hamper its widespread use. In this study, we describe a series of pyrazolopyrimidine- and imidazopyrazine-based compounds that are potent inhibitors of PfCDPK4, which is a calcium-activated Plasmodium protein kinase that is essential for exflagellation of male gametocytes. Thus, PfCDPK4 is essential for the sexual development of Plasmodium parasites and their ability to infect mosquitoes. We demonstrate that two structural features in the ATP-binding site of PfCDPK4 can be exploited in order to obtain potent and selective inhibitors of this enzyme. Furthermore, we demonstrate that pyrazolopyrimidine-based inhibitors that are potent inhibitors of the in vitro activity of PfCDPK4 are also able to block Plasmodium falciparum exflagellation with no observable toxicity to human cells. This medicinal chemistry effort serves as a valuable starting point in the development of safe, transmission-blocking agents for the control of malaria.
Collapse
Affiliation(s)
| | - Kayode K Ojo
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Steven M Johnson
- Department of Chemistry, University of Washington, Seattle, WA 98195-1700, USA
| | - Zhongsheng Zhang
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Stephen E Leonard
- Department of Chemistry, University of Washington, Seattle, WA 98195-1700, USA
| | - Arinjay Mitra
- Department of Chemistry, University of Washington, Seattle, WA 98195-1700, USA
| | - Ryan Choi
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Molly C Reid
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Katelyn R Keyloun
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Anna M W Fox
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Mark Kennedy
- Seattle Biomedical Research Institute, Seattle, WA, USA
| | | | - Jen C C Hume
- Seattle Biomedical Research Institute, Seattle, WA, USA
| | - Stefan Kappe
- Seattle Biomedical Research Institute, Seattle, WA, USA; Departments of Global Health, University of Washington, Seattle, WA, USA
| | | | - Erkang Fan
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Ethan A Merritt
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Wesley C Van Voorhis
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA; Departments of Global Health, University of Washington, Seattle, WA, USA; Departments of Microbiology, University of Washington, Seattle, WA, USA.
| | - Dustin J Maly
- Department of Chemistry, University of Washington, Seattle, WA 98195-1700, USA.
| |
Collapse
|
20
|
Biamonte MA, Wanner J, Le Roch KG. Recent advances in malaria drug discovery. Bioorg Med Chem Lett 2013; 23:2829-43. [PMID: 23587422 PMCID: PMC3762334 DOI: 10.1016/j.bmcl.2013.03.067] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 03/11/2013] [Accepted: 03/20/2013] [Indexed: 01/18/2023]
Abstract
This digest covers some of the most relevant progress in malaria drug discovery published between 2010 and 2012. There is an urgent need to develop new antimalarial drugs. Such drugs can target the blood stage of the disease to alleviate the symptoms, the liver stage to prevent relapses, and the transmission stage to protect other humans. The pipeline for the blood stage is becoming robust, but this should not be a source of complacency, as the current therapies set a high standard. Drug discovery efforts directed towards the liver and transmission stages are in their infancy but are receiving increasing attention as targeting these stages could be instrumental in eradicating malaria.
Collapse
Affiliation(s)
- Marco A Biamonte
- Drug Discovery for Tropical Diseases, Suite 230, San Diego, CA 92121, USA.
| | | | | |
Collapse
|
21
|
|
22
|
|