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Ong HW, Adderley J, Tobin AB, Drewry DH, Doerig C. Parasite and host kinases as targets for antimalarials. Expert Opin Ther Targets 2023; 27:151-169. [PMID: 36942408 DOI: 10.1080/14728222.2023.2185511] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
INTRODUCTION The deployment of Artemisinin-based combination therapies and transmission control measures led to a decrease in the global malaria burden over the recent decades. Unfortunately, this trend is now reversing, in part due to resistance against available treatments, calling for the development of new drugs against untapped targets to prevent cross-resistance. AREAS COVERED In view of their demonstrated druggability in noninfectious diseases, protein kinases represent attractive targets. Kinase-focussed antimalarial drug discovery is facilitated by the availability of kinase-targeting scaffolds and large libraries of inhibitors, as well as high-throughput phenotypic and biochemical assays. We present an overview of validated Plasmodium kinase targets and their inhibitors, and briefly discuss the potential of host cell kinases as targets for host-directed therapy. EXPERT OPINION We propose priority research areas, including (i) diversification of Plasmodium kinase targets (at present most efforts focus on a very small number of targets); (ii) polypharmacology as an avenue to limit resistance (kinase inhibitors are highly suitable in this respect); and (iii) preemptive limitation of resistance through host-directed therapy (targeting host cell kinases that are required for parasite survival) and transmission-blocking through targeting sexual stage-specific kinases as a strategy to protect curative drugs from the spread of resistance.
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Affiliation(s)
- Han Wee Ong
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC USA
| | - Jack Adderley
- Department of Laboratory Medicine, School of Health and Biomedical Sciences, Rmit University, Bundoora VIC Australia
| | - Andrew B Tobin
- Advanced Research Centre, University of Glasgow, Glasgow, UK
| | - David H Drewry
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC USA
| | - Christian Doerig
- Department of Laboratory Medicine, School of Health and Biomedical Sciences, Rmit University, Bundoora VIC Australia
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2
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Sharma M, Choudhury H, Roy R, Michaels SA, Ojo KK, Bansal A. CDPKs: The critical decoders of calcium signal at various stages of malaria parasite development. Comput Struct Biotechnol J 2021; 19:5092-5107. [PMID: 34589185 PMCID: PMC8453137 DOI: 10.1016/j.csbj.2021.08.054] [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: 04/24/2021] [Revised: 08/31/2021] [Accepted: 08/31/2021] [Indexed: 12/13/2022] Open
Abstract
Calcium ions are used as important signals during various physiological processes. In malaria parasites, Plasmodium spp., calcium dependent protein kinases (CDPKs) have acquired the unique ability to sense and transduce calcium signals at various critical steps during the lifecycle, either through phosphorylation of downstream substrates or mediating formation of high molecular weight protein complexes. Calcium signaling cascades establish important crosstalk events with signaling pathways mediated by other secondary messengers such as cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). CDPKs play critical roles at various important physiological steps during parasite development in vertebrates and mosquitoes. They are also important for transmission of the parasite between the two hosts. Combined with the fact that CDPKs are not present in humans, they continue to be pursued as important targets for development of anti-malarial drugs.
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Affiliation(s)
- Manish Sharma
- Molecular Parasitology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Himashree Choudhury
- Molecular Parasitology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Rajarshi Roy
- Molecular Parasitology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Samantha A. Michaels
- Center for Emerging and Re-emerging Infectious Diseases, Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98109 USA
| | - Kayode K. Ojo
- Center for Emerging and Re-emerging Infectious Diseases, Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98109 USA
| | - Abhisheka Bansal
- Molecular Parasitology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
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3
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Mustière R, Vanelle P, Primas N. Plasmodial Kinase Inhibitors Targeting Malaria: Recent Developments. Molecules 2020; 25:E5949. [PMID: 33334080 PMCID: PMC7765515 DOI: 10.3390/molecules25245949] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/11/2020] [Accepted: 12/11/2020] [Indexed: 11/17/2022] Open
Abstract
Recent progress in reducing malaria cases and ensuing deaths is threatened by factors like mutations that induce resistance to artemisinin derivatives. Multiple drugs are currently in clinical trials for malaria treatment, including some with novel mechanisms of action. One of these, MMV390048, is a plasmodial kinase inhibitor. This review lists the recently developed molecules which target plasmodial kinases. A systematic review of the literature was performed using CAPLUS and MEDLINE databases from 2005 to 2020. It covers a total of 60 articles and describes about one hundred compounds targeting 22 plasmodial kinases. This work highlights the strong potential of compounds targeting plasmodial kinases for future drug therapies. However, the majority of the Plasmodium kinome remains to be explored.
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Affiliation(s)
| | - Patrice Vanelle
- Aix Marseille Univ, CNRS, ICR UMR 7273, Equipe Pharmaco-Chimie Radicalaire, Faculté de Pharmacie, 13385 Marseille CEDEX 05, France;
| | - Nicolas Primas
- Aix Marseille Univ, CNRS, ICR UMR 7273, Equipe Pharmaco-Chimie Radicalaire, Faculté de Pharmacie, 13385 Marseille CEDEX 05, France;
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4
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Moolman C, van der Sluis R, Beteck RM, Legoabe LJ. An Update on Development of Small-Molecule Plasmodial Kinase Inhibitors. Molecules 2020; 25:E5182. [PMID: 33171706 PMCID: PMC7664427 DOI: 10.3390/molecules25215182] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 12/21/2022] Open
Abstract
Malaria control relies heavily on the small number of existing antimalarial drugs. However, recurring antimalarial drug resistance necessitates the continual generation of new antimalarial drugs with novel modes of action. In order to shift the focus from only controlling this disease towards elimination and eradication, next-generation antimalarial agents need to address the gaps in the malaria drug arsenal. This includes developing drugs for chemoprotection, treating severe malaria and blocking transmission. Plasmodial kinases are promising targets for next-generation antimalarial drug development as they mediate critical cellular processes and some are active across multiple stages of the parasite's life cycle. This review gives an update on the progress made thus far with regards to plasmodial kinase small-molecule inhibitor development.
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Affiliation(s)
- Chantalle Moolman
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa; (C.M.); (R.M.B.)
| | - Rencia van der Sluis
- Focus Area for Human Metabolomics, Biochemistry, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa;
| | - Richard M. Beteck
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa; (C.M.); (R.M.B.)
| | - Lesetja J. Legoabe
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa; (C.M.); (R.M.B.)
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5
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Abstract
Malaria is one of the most impacting public health problems in tropical and subtropical areas of the globe, with approximately 200 million cases worldwide annually. In the absence of an effective vaccine, rapid treatment is vital for effective malaria control. However, parasite resistance to currently available drugs underscores the urgent need for identifying new antimalarial therapies with new mechanisms of action. Among potential drug targets for developing new antimalarial candidates, protein kinases are attractive. These enzymes catalyze the phosphorylation of several proteins, thereby regulating a variety of cellular processes and playing crucial roles in the development of all stages of the malaria parasite life cycle. Moreover, the large phylogenetic distance between Plasmodium species and its human host is reflected in marked differences in structure and function of malaria protein kinases between the homologs of both species, indicating that selectivity can be attained. In this review, we describe the functions of the different types of Plasmodium kinases and highlight the main recent advances in the discovery of kinase inhibitors as potential new antimalarial drug candidates.
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Cabrera DG, Horatscheck A, Wilson CR, Basarab G, Eyermann CJ, Chibale K. Plasmodial Kinase Inhibitors: License to Cure? J Med Chem 2018; 61:8061-8077. [PMID: 29771541 PMCID: PMC6166223 DOI: 10.1021/acs.jmedchem.8b00329] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
Advances
in the genetics, function, and stage-specificity of Plasmodium kinases has driven robust efforts to identify
targets for the design of antimalarial therapies. Reverse genomics
following phenotypic screening against Plasmodia or
related parasites has uncovered vulnerable kinase targets including
PI4K, PKG, and GSK-3, an approach bolstered by access to human disease-directed
kinase libraries. Alternatively, screening compound libraries against Plasmodium kinases has successfully led to inhibitors with
antiplasmodial activity. As with other therapeutic areas, optimizing
compound ADMET and PK properties in parallel with target inhibitory
potency and whole cell activity becomes paramount toward advancing
compounds as clinical candidates. These and other considerations will
be discussed in the context of progress achieved toward deriving important,
novel mode-of-action kinase-inhibiting antimalarial medicines.
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7
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Kato K, Sugi T, Takemae H, Takano R, Gong H, Ishiwa A, Horimoto T, Akashi H. Characterization of a Toxoplasma gondii calcium calmodulin-dependent protein kinase homolog. Parasit Vectors 2016; 9:405. [PMID: 27444499 PMCID: PMC4957278 DOI: 10.1186/s13071-016-1676-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 06/30/2016] [Indexed: 12/04/2022] Open
Abstract
Background Toxoplasma gondii is an obligate intracellular parasite of the phylum Apicomplexa and a major pathogen of animals and immunocompromised humans, in whom it causes encephalitis. Understanding the mechanism of tachyzoite invasion is important for the discovery of new drug targets and may serve as a model for the study of other apicomplexan parasites. We previously showed that Plasmodium falciparum expresses a homolog of human calcium calmodulin-dependent protein kinase (CaMK) that is important for host cell invasion. In this study, to identify novel targets for the treatment of Toxoplasma gondii infection (another apicomplexan parasite), we sought to identify a CaMK-like protein in the T. gondii genome and to characterize its role in the life-cycle of this parasite. Methods An in vitro kinase assay was performed to assess the phosphorylation activities of a novel CaMK-like protein in T. gondii by using purified proteins with various concentrations of calcium, calmodulin antagonists, or T. gondii glideosome proteins. Indirect immunofluorescence microscopy was performed to detect the localization of this protein kinase by using the antibodies against this protein and organellar maker proteins of T. gondii. Results We identified a novel CaMK homolog in T. gondii, T. gondii CaMK-related kinase (TgCaMKrk), which exhibits calmodulin-independent autophosphorylation and substrate phosphorylation activity. However, calmodulin antagonists had no effect on its kinase activity. In T. gondii-infected cells, TgCaMKrk localized to the apical ends of extracellular and intracellular tachyzoites. TgCaMKrk phosphorylated TgGAP45 for phosphorylation in vitro. Conclusions Our data improve our understanding of T. gondii motility and infection, the interaction between parasite protein kinases and glideosomes, and drug targets for protozoan diseases.
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Affiliation(s)
- Kentaro Kato
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido, 080-8555, Japan. .,Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
| | - Tatsuki Sugi
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido, 080-8555, Japan.,Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Hitoshi Takemae
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido, 080-8555, Japan.,Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Ryo Takano
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido, 080-8555, Japan
| | - Haiyan Gong
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Akiko Ishiwa
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido, 080-8555, Japan.,Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Taisuke Horimoto
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Hiroomi Akashi
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
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8
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Kato K. Evaluation of the enzyme activity of protozoan protein kinases by using an in vitro kinase assay. Parasitol Int 2016; 65:510-513. [PMID: 27425601 DOI: 10.1016/j.parint.2016.07.006] [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: 10/30/2015] [Revised: 06/30/2016] [Accepted: 07/13/2016] [Indexed: 10/21/2022]
Abstract
The life cycles of parasites are more complicated than those of other biological species. Protein kinases (PKs) encoded by parasites are the main triggers of life stage conversions. Phosphorylation by cellular PKs regulates important cellular processes, and the protozoan genome contains many PKs. Some PK inhibitors inhibit specific parasite life cycle event. In this report, I present a practical approach to expressing and purifying protozoan PKs by using a wheat germ cell-free protein synthesis system and I assess the phosphorylation activities of protozoan PKs by using an in vitro kinase assay.
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Affiliation(s)
- Kentaro Kato
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
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9
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Ojo KK, Eastman RT, Vidadala R, Zhang Z, Rivas KL, Choi R, Lutz JD, Reid MC, Fox AMW, Hulverson MA, Kennedy M, Isoherranen N, Kim LM, Comess KM, Kempf DJ, Verlinde CLMJ, Su XZ, Kappe SHI, Maly DJ, Fan E, Van Voorhis WC. A specific inhibitor of PfCDPK4 blocks malaria transmission: chemical-genetic validation. J Infect Dis 2014; 209:275-84. [PMID: 24123773 PMCID: PMC3873787 DOI: 10.1093/infdis/jit522] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 06/07/2013] [Indexed: 01/03/2023] Open
Abstract
Malaria parasites are transmitted by mosquitoes, and blocking parasite transmission is critical in reducing or eliminating malaria in endemic regions. Here, we report the pharmacological characterization of a new class of malaria transmission-blocking compounds that acts via the inhibition of Plasmodia CDPK4 enzyme. We demonstrate that these compounds achieved selectivity over mammalian kinases by capitalizing on a small serine gatekeeper residue in the active site of the Plasmodium CDPK4 enzyme. To directly confirm the mechanism of action of these compounds, we generated P. falciparum parasites that express a drug-resistant methionine gatekeeper (S147 M) CDPK4 mutant. Mutant parasites showed a shift in exflagellation EC50 relative to the wild-type strains in the presence of compound 1294, providing chemical-genetic evidence that CDPK4 is the target of the compound. Pharmacokinetic analyses suggest that coformulation of this transmission-blocking agent with asexual stage antimalarials such as artemisinin combination therapy (ACT) is a promising option for drug delivery that may reduce transmission of malaria including drug-resistant strains. Ongoing studies include refining the compounds to improve efficacy and toxicological properties for efficient blocking of malaria transmission.
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Affiliation(s)
- Kayode K. Ojo
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle
| | - Richard T. Eastman
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | | | | | - Kasey L. Rivas
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle
| | - Ryan Choi
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle
| | - Justin D. Lutz
- Department of Pharmaceutics, University of Washington, Seattle
| | - Molly C. Reid
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle
| | - Anna M. W. Fox
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle
| | - Matthew A. Hulverson
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle
| | - Mark Kennedy
- Seattle Biomedical Research Institute, Washington
| | | | - Laura M. Kim
- Global Pharmaceutical R&D, AbbVie, North Chicago, Illinois
| | | | - Dale J. Kempf
- Global Pharmaceutical R&D, AbbVie, North Chicago, Illinois
| | | | - Xin-zhuan Su
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | | | | | | | - Wesley C. Van Voorhis
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle
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10
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Iwanaga T, Sugi T, Kobayashi K, Takemae H, Gong H, Ishiwa A, Murakoshi F, Recuenco FC, Horimoto T, Akashi H, Kato K. Characterization of Plasmodium falciparum cdc2-related kinase and the effects of a CDK inhibitor on the parasites in erythrocytic schizogony. Parasitol Int 2013; 62:423-30. [DOI: 10.1016/j.parint.2013.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 03/27/2013] [Accepted: 05/11/2013] [Indexed: 11/26/2022]
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11
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Lauciello L, Kappes B, Scapozza L, Perozzo R. Expression, purification and biochemical characterization of recombinant Ca-dependent protein kinase 2 of the malaria parasite Plasmodium falciparum. Protein Expr Purif 2013; 90:170-7. [PMID: 23792132 DOI: 10.1016/j.pep.2013.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 06/02/2013] [Accepted: 06/06/2013] [Indexed: 01/17/2023]
Abstract
Calcium-dependent protein kinases (CDPKs) are serine/threonine kinases that react in response to calcium which functions as a trigger for several mechanisms in plants and invertebrates, but not in mammals. Recent structural studies have defined the role of calcium in the activation of CDPKs and have elucidated the important structural changes caused by calcium in order to allow the kinase domain of CDPK to bind and phosphorylate the substrate. However, the role of autophosphorylation in CDPKs is still not fully understood. In Plasmodium falciparum, seven CDPKs have been identified by sequence comparison, and four of them have been characterized and assigned to play a role in parasite motility, gametogenesis and egress from red blood cells. Although PfCDPK2 was already discovered in 1997, little is known about this enzyme and its metabolic role. In this work, we have expressed and purified PfCDPK2 at high purity in its unphosphorylated form and characterized its biochemical properties. Moreover, propositions about putative substrates in P. falciparum are made based on the analysis of the phosphorylation sites on the artificial substrate myelin basic protein (MBP).
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Affiliation(s)
- Leonardo Lauciello
- Pharmaceutical Biochemistry Group, School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland
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12
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Ojo KK, Pfander C, Mueller NR, Burstroem C, Larson ET, Bryan CM, Fox AMW, Reid MC, Johnson SM, Murphy RC, Kennedy M, Mann H, Leibly DJ, Hewitt SN, Verlinde CLMJ, Kappe S, Merritt EA, Maly DJ, Billker O, Van Voorhis WC. Transmission of malaria to mosquitoes blocked by bumped kinase inhibitors. J Clin Invest 2012; 122:2301-5. [PMID: 22565309 DOI: 10.1172/jci61822] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 03/28/2012] [Indexed: 12/28/2022] Open
Abstract
Effective control and eradication of malaria will require new tools to prevent transmission. Current antimalarial therapies targeting the asexual stage of Plasmodium do not prevent transmission of circulating gametocytes from infected humans to mosquitoes. Here, we describe a new class of transmission-blocking compounds, bumped kinase inhibitors (BKIs), which inhibit microgametocyte exflagellation. Oocyst formation and sporozoite production, necessary for transmission to mammals, were inhibited in mosquitoes fed on either BKI-1-treated human blood or mice treated with BKI-1. BKIs are hypothesized to act via inhibition of Plasmodium calcium-dependent protein kinase 4 and predicted to have little activity against mammalian kinases. Our data show that BKIs do not inhibit proliferation of mammalian cell lines and are well tolerated in mice. Used in combination with drugs active against asexual stages of Plasmodium, BKIs could prove an important tool for malaria control and eradication.
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Affiliation(s)
- Kayode K Ojo
- Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington 98195-6423, USA
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13
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Plattner H, Sehring IM, Mohamed IK, Miranda K, De Souza W, Billington R, Genazzani A, Ladenburger EM. Calcium signaling in closely related protozoan groups (Alveolata): non-parasitic ciliates (Paramecium, Tetrahymena) vs. parasitic Apicomplexa (Plasmodium, Toxoplasma). Cell Calcium 2012; 51:351-82. [PMID: 22387010 DOI: 10.1016/j.ceca.2012.01.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 01/10/2012] [Accepted: 01/12/2012] [Indexed: 12/20/2022]
Abstract
The importance of Ca2+-signaling for many subcellular processes is well established in higher eukaryotes, whereas information about protozoa is restricted. Recent genome analyses have stimulated such work also with Alveolates, such as ciliates (Paramecium, Tetrahymena) and their pathogenic close relatives, the Apicomplexa (Plasmodium, Toxoplasma). Here we compare Ca2+ signaling in the two closely related groups. Acidic Ca2+ stores have been characterized in detail in Apicomplexa, but hardly in ciliates. Two-pore channels engaged in Ca2+-release from acidic stores in higher eukaryotes have not been stingently characterized in either group. Both groups are endowed with plasma membrane- and endoplasmic reticulum-type Ca2+-ATPases (PMCA, SERCA), respectively. Only recently was it possible to identify in Paramecium a number of homologs of ryanodine and inositol 1,3,4-trisphosphate receptors (RyR, IP3R) and to localize them to widely different organelles participating in vesicle trafficking. For Apicomplexa, physiological experiments suggest the presence of related channels although their identity remains elusive. In Paramecium, IP3Rs are constitutively active in the contractile vacuole complex; RyR-related channels in alveolar sacs are activated during exocytosis stimulation, whereas in the parasites the homologous structure (inner membrane complex) may no longer function as a Ca2+ store. Scrutinized comparison of the two closely related protozoan phyla may stimulate further work and elucidate adaptation to parasitic life. See also "Conclusions" section.
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Affiliation(s)
- H Plattner
- Department of Biology, University of Konstanz, P.O. Box 5560, 78457 Konstanz, Germany.
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14
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Kato K, Sugi T, Iwanaga T. Roles of Apicomplexan protein kinases at each life cycle stage. Parasitol Int 2011; 61:224-34. [PMID: 22209882 DOI: 10.1016/j.parint.2011.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 12/12/2011] [Accepted: 12/18/2011] [Indexed: 01/21/2023]
Abstract
Inhibitors of cellular protein kinases have been reported to inhibit the development of Apicomplexan parasites, suggesting that the functions of protozoan protein kinases are critical for their life cycle. However, the specific roles of these protein kinases cannot be determined using only these inhibitors without molecular analysis, including gene disruption. In this report, we describe the functions of Apicomplexan protein kinases in each parasite life stage and the potential of pre-existing protein kinase inhibitors as Apicomplexan drugs against, mainly, Plasmodium and Toxoplasma.
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Affiliation(s)
- Kentaro Kato
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
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15
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Boisson B, Lacroix C, Bischoff E, Gueirard P, Bargieri DY, Franke-Fayard B, Janse CJ, Ménard R, Baldacci P. The novel putative transporter NPT1 plays a critical role in early stages of Plasmodium berghei sexual development. Mol Microbiol 2011; 81:1343-57. [PMID: 21752110 DOI: 10.1111/j.1365-2958.2011.07767.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Transmission of Plasmodium species from a mammalian host to the mosquito vector requires the uptake, during an infected blood meal, of gametocytes, the precursor cells of the gametes. Relatively little is known about the molecular mechanisms involved in the developmental switch from asexual development to sexual differentiation or the maturation and survival of gametocytes. Here, we show that a gene coding for a novel putative transporter, NPT1, plays a crucial role in the development of Plasmodium berghei gametocytes. Parasites lacking NPT1 are severely compromised in the production of gametocytes and the rare gametocytes produced are unable to differentiate into fertile gametes. This is the earliest block in gametocytogenesis obtained by reverse genetics and the first to demonstrate the role of a protein with a putative transport function in sexual development. These results and the high degree of conservation of NPT1 in Plasmodium species suggest that this protein could be an attractive target for the development of novel drugs to block the spread of malaria.
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Affiliation(s)
- Bertrand Boisson
- Institut Pasteur, Biologie et Génétique du Paludisme, 75724 Paris, France.
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Identification of Toxoplasma gondii cAMP dependent protein kinase and its role in the tachyzoite growth. PLoS One 2011; 6:e22492. [PMID: 21799871 PMCID: PMC3140512 DOI: 10.1371/journal.pone.0022492] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 06/28/2011] [Indexed: 12/18/2022] Open
Abstract
Background cAMP-dependent protein kinase (PKA) has been implicated in the asexual stage of the Toxoplasma gondii life cycle through assaying the effect of a PKA-specific inhibitor on its growth rate. Since inhibition of the host cell PKA cannot be ruled out, a more precise evaluation of the role of PKA, as well as characterization of the kinase itself, is necessary. Methodology/Principal Finding The inhibitory effects of two PKA inhibitors, H89, an ATP-competitive chemical inhibitor, and PKI, a substrate-competitive mammalian natural peptide inhibitor, were estimated. In the in vitro kinase assay, the inhibitory effect of PKI on a recombinant T. gondii PKA catalytic subunit (TgPKA-C) was weaker compared to that on mammalian PKA-C. In a tachyzoite growth assay, PKI had little effect on the growth of tachyzoites, whereas H89 strongly inhibited it. Moreover, T. gondii PKA regulatory subunit (TgPKA-R)-overexpressing tachyzoites showed a significant growth defect. Conclusions/Significance Our data suggest that PKA plays an important role in the growth of tachyzoites, and the inhibitory effect of substrate-competitive inhibitor PKI on T. gondii PKA was low compared to that of the ATP competitive inhibitor H89.
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