101
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Pandey K, Ferreira PE, Ishikawa T, Nagai T, Kaneko O, Yahata K. Ca(2+) monitoring in Plasmodium falciparum using the yellow cameleon-Nano biosensor. Sci Rep 2016; 6:23454. [PMID: 27006284 PMCID: PMC4804237 DOI: 10.1038/srep23454] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 03/07/2016] [Indexed: 11/09/2022] Open
Abstract
Calcium (Ca(2+))-mediated signaling is a conserved mechanism in eukaryotes, including the human malaria parasite, Plasmodium falciparum. Due to its small size (<10 μm) measurement of intracellular Ca(2+) in Plasmodium is technically challenging, and thus Ca(2+) regulation in this human pathogen is not well understood. Here we analyze Ca(2+) homeostasis via a new approach using transgenic P. falciparum expressing the Ca(2+) sensor yellow cameleon (YC)-Nano. We found that cytosolic Ca(2+) concentration is maintained at low levels only during the intraerythrocytic trophozoite stage (30 nM), and is increased in the other blood stages (>300 nM). We determined that the mammalian SERCA inhibitor thapsigargin and antimalarial dihydroartemisinin did not perturb SERCA activity. The change of the cytosolic Ca(2+) level in P. falciparum was additionally detectable by flow cytometry. Thus, we propose that the developed YC-Nano-based system is useful to study Ca(2+) signaling in P. falciparum and is applicable for drug screening.
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Affiliation(s)
- Kishor Pandey
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
- Nepal Academy of Science and Technology (NAST), GPO Box: 3323, Khumaltar, Lalitpur, Nepal
| | - Pedro E. Ferreira
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
- School of Biological Science, Nanyang Technological University, Singapore
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
| | - Takeshi Ishikawa
- Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Takeharu Nagai
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Osamu Kaneko
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Kazuhide Yahata
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
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102
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Crowther GJ, Hillesland HK, Keyloun KR, Reid MC, Lafuente-Monasterio MJ, Ghidelli-Disse S, Leonard SE, He P, Jones JC, Krahn MM, Mo JS, Dasari KS, Fox AMW, Boesche M, El Bakkouri M, Rivas KL, Leroy D, Hui R, Drewes G, Maly DJ, Van Voorhis WC, Ojo KK. Biochemical Screening of Five Protein Kinases from Plasmodium falciparum against 14,000 Cell-Active Compounds. PLoS One 2016; 11:e0149996. [PMID: 26934697 PMCID: PMC4774911 DOI: 10.1371/journal.pone.0149996] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 02/08/2016] [Indexed: 11/18/2022] Open
Abstract
In 2010 the identities of thousands of anti-Plasmodium compounds were released publicly to facilitate malaria drug development. Understanding these compounds' mechanisms of action--i.e., the specific molecular targets by which they kill the parasite--would further facilitate the drug development process. Given that kinases are promising anti-malaria targets, we screened ~14,000 cell-active compounds for activity against five different protein kinases. Collections of cell-active compounds from GlaxoSmithKline (the ~13,000-compound Tres Cantos Antimalarial Set, or TCAMS), St. Jude Children's Research Hospital (260 compounds), and the Medicines for Malaria Venture (the 400-compound Malaria Box) were screened in biochemical assays of Plasmodium falciparum calcium-dependent protein kinases 1 and 4 (CDPK1 and CDPK4), mitogen-associated protein kinase 2 (MAPK2/MAP2), protein kinase 6 (PK6), and protein kinase 7 (PK7). Novel potent inhibitors (IC50 < 1 μM) were discovered for three of the kinases: CDPK1, CDPK4, and PK6. The PK6 inhibitors are the most potent yet discovered for this enzyme and deserve further scrutiny. Additionally, kinome-wide competition assays revealed a compound that inhibits CDPK4 with few effects on ~150 human kinases, and several related compounds that inhibit CDPK1 and CDPK4 yet have limited cytotoxicity to human (HepG2) cells. Our data suggest that inhibiting multiple Plasmodium kinase targets without harming human cells is challenging but feasible.
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Affiliation(s)
- Gregory J. Crowther
- Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Heidi K. Hillesland
- Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Katelyn R. Keyloun
- Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Molly C. Reid
- Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | | | - Sonja Ghidelli-Disse
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline R&D, Heidelberg, Germany
| | - Stephen E. Leonard
- Department of Chemistry, University of Washington, Seattle, Washington, United States of America
| | - Panqing He
- Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Jackson C. Jones
- Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Mallory M. Krahn
- Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Jack S. Mo
- Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Kartheek S. Dasari
- Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Anna M. W. Fox
- Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Markus Boesche
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline R&D, Heidelberg, Germany
| | - Majida El Bakkouri
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Kasey L. Rivas
- Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Didier Leroy
- Drug Discovery, Medicines for Malaria Venture, Geneva, Switzerland
| | - Raymond Hui
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
| | - Gerard Drewes
- Cellzome GmbH, Molecular Discovery Research, GlaxoSmithKline R&D, Heidelberg, Germany
| | - Dustin J. Maly
- Department of Chemistry, University of Washington, Seattle, Washington, United States of America
| | - Wesley C. Van Voorhis
- Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Kayode K. Ojo
- Division of Allergy & Infectious Diseases, Department of Medicine, University of Washington, Seattle, Washington, United States of America
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103
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Ganesan SM, Falla A, Goldfless SJ, Nasamu AS, Niles JC. Synthetic RNA-protein modules integrated with native translation mechanisms to control gene expression in malaria parasites. Nat Commun 2016; 7:10727. [PMID: 26925876 PMCID: PMC4773503 DOI: 10.1038/ncomms10727] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 01/15/2016] [Indexed: 12/12/2022] Open
Abstract
Synthetic posttranscriptional regulation of gene expression is important for understanding fundamental biology and programming new cellular processes in synthetic biology. Previous strategies for regulating translation in eukaryotes have focused on disrupting individual steps in translation, including initiation and mRNA cleavage. In emphasizing modularity and cross-organism functionality, these systems are designed to operate orthogonally to native control mechanisms. Here we introduce a broadly applicable strategy for robustly controlling protein translation by integrating synthetic translational control via a small-molecule-regulated RNA–protein module with native mechanisms that simultaneously regulate multiple facets of cellular RNA fate. We demonstrate that this strategy reduces ‘leakiness' to improve overall expression dynamic range, and can be implemented without sacrificing modularity and cross-organism functionality. We illustrate this in Saccharomyces cerevisae and the non-model human malarial parasite, Plasmodium falciparum. Given the limited functional genetics toolkit available for P. falciparum, we establish the utility of this strategy for defining essential genes. Current strategies for regulatory control of gene expression are orthogonal to the host organism mechanisms. Here the authors demonstrate an RNA aptamer controlled system integrated into native regulatory pathways in the parasite Plasmodium falciparum.
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Affiliation(s)
- Suresh M Ganesan
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, 02139 Massachusetts, USA
| | - Alejandra Falla
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, 02139 Massachusetts, USA
| | - Stephen J Goldfless
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, 02139 Massachusetts, USA
| | - Armiyaw S Nasamu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, 02139 Massachusetts, USA
| | - Jacquin C Niles
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, 02139 Massachusetts, USA
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104
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Soni R, Sharma D, Bhatt TK. Plasmodium falciparum Secretome in Erythrocyte and Beyond. Front Microbiol 2016; 7:194. [PMID: 26925057 PMCID: PMC4759260 DOI: 10.3389/fmicb.2016.00194] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 02/05/2016] [Indexed: 01/19/2023] Open
Abstract
Plasmodium falciparum is the causative agent of deadly malaria disease. It is an intracellular eukaryote and completes its multi-stage life cycle spanning the two hosts viz, mosquito and human. In order to habituate within host environment, parasite conform several strategies to evade host immune responses such as surface antigen polymorphism or modulation of host immune system and it is mediated by secretion of proteins from parasite to the host erythrocyte and beyond, collectively known as, malaria secretome. In this review, we will discuss about the deployment of parasitic secretory protein in mechanism implicated for immune evasion, protein trafficking, providing virulence, changing permeability and cyto-adherence of infected erythrocyte. We will be covering the possibilities of developing malaria secretome as a drug/vaccine target. This gathered information will be worthwhile in depicting a well-organized picture for host-pathogen interplay during the malaria infection and may also provide some clues for the development of novel anti-malarial therapies.
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Affiliation(s)
- Rani Soni
- Department of Biotechnology, School of Life Sciences, Central University of Rajasthan Rajasthan, India
| | - Drista Sharma
- Department of Biotechnology, School of Life Sciences, Central University of Rajasthan Rajasthan, India
| | - Tarun K Bhatt
- Department of Biotechnology, School of Life Sciences, Central University of Rajasthan Rajasthan, India
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105
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Brochet M, Billker O. Calcium signalling in malaria parasites. Mol Microbiol 2016; 100:397-408. [PMID: 26748879 DOI: 10.1111/mmi.13324] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2016] [Indexed: 12/24/2022]
Abstract
Ca(2+) is a ubiquitous intracellular messenger in malaria parasites with important functions in asexual blood stages responsible for malaria symptoms, the preceding liver-stage infection and transmission through the mosquito. Intracellular messengers amplify signals by binding to effector molecules that trigger physiological changes. The characterisation of some Ca(2+) effector proteins has begun to provide insights into the vast range of biological processes controlled by Ca(2+) signalling in malaria parasites, including host cell egress and invasion, protein secretion, motility and cell cycle regulation. Despite the importance of Ca(2+) signalling during the life cycle of malaria parasites, little is known about Ca(2+) homeostasis. Recent findings highlighted that upstream of stage-specific Ca(2+) effectors is a conserved interplay between second messengers to control critical intracellular Ca(2+) signals throughout the life cycle. The identification of the molecular mechanisms integrating stage-transcending mechanisms of Ca(2+) homeostasis in a network of stage-specific regulator and effector pathways now represents a major challenge for a meaningful understanding of Ca(2+) signalling in malaria parasites.
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Affiliation(s)
- Mathieu Brochet
- Faculty of Medicine, Department of Microbiology and Molecular Medicine, University of Geneva, 1 Rue Michel-Servet, CH-1211 Geneva 4, Switzerland.,UMR5235 CNRS-Université Montpellier 2, 34095, Montpellier, France
| | - Oliver Billker
- Wellcome Trust Sanger Institute, Malaria Programme, CB10 1SA, Hinxton, UK
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106
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Fernández-Álvaro E, Hong WD, Nixon GL, O’Neill PM, Calderón F. Antimalarial Chemotherapy: Natural Product Inspired Development of Preclinical and Clinical Candidates with Diverse Mechanisms of Action. J Med Chem 2016; 59:5587-603. [DOI: 10.1021/acs.jmedchem.5b01485] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Elena Fernández-Álvaro
- Diseases of the Developing World, Tres
Cantos Medicines Development Campus, GlaxoSmithKline, c/Severo Ochoa, 2, 28760, Tres Cantos, Madrid, Spain
| | - W. David Hong
- Robert Robinson
Laboratories, Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
| | - Gemma L. Nixon
- Robert Robinson
Laboratories, Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
| | - Paul M. O’Neill
- Robert Robinson
Laboratories, Department of Chemistry, University of Liverpool, Crown Street, Liverpool L69 7ZD, U.K
| | - Félix Calderón
- Diseases of the Developing World, Tres
Cantos Medicines Development Campus, GlaxoSmithKline, c/Severo Ochoa, 2, 28760, Tres Cantos, Madrid, Spain
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107
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Spiroindolone NITD609 is a novel antimalarial drug that targets the P-type ATPase PfATP4. Future Med Chem 2016; 8:227-38. [PMID: 26824174 DOI: 10.4155/fmc.15.177] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Malaria is caused by the Plasmodium parasite and is a major health problem leading to many deaths worldwide. Lack of a vaccine and increasing drug resistance highlights the need for new antimalarial drugs with novel targets. Antiplasmodial activity of spiroindolones was discovered through whole-cell, phenotypic screening methods. Optimization of the lead spiroindolone improved both potency and pharmacokinetic properties leading to drug candidate NITD609 which has produced encouraging results in clinical trials. Spiroindolones inhibit PfATP4, a P-type Na(+)-ATPase in the plasma membrane of the parasite, causing a fatal disruption of its sodium homeostasis. Other diverse compounds from the Malaria Box appear to target PfATP4 warranting further research into its structure and binding with NITD609 and other potential antimalarial drugs.
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108
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Maduramicin Rapidly Eliminates Malaria Parasites and Potentiates the Gametocytocidal Activity of the Pyrazoleamide PA21A050. Antimicrob Agents Chemother 2015; 60:1492-9. [PMID: 26711768 DOI: 10.1128/aac.01928-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 12/08/2015] [Indexed: 12/23/2022] Open
Abstract
New strategies targeting Plasmodium falciparum gametocytes, the sexual-stage parasites that are responsible for malaria transmission, are needed to eradicate this disease. Most commonly used antimalarials are ineffective against P. falciparum gametocytes, allowing patients to continue to be infectious for over a week after asexual parasite clearance. A recent screen for gametocytocidal compounds demonstrated that the carboxylic polyether ionophore maduramicin is active at low nanomolar concentrations against P. falciparum sexual stages. In this study, we showed that maduramicin has an EC50 (effective concentration that inhibits the signal by 50%) of 14.8 nM against late-stage gametocytes and significantly blocks in vivo transmission in a mouse model of malaria transmission. In contrast to other reported gametocytocidal agents, maduramicin acts rapidly in vitro, eliminating gametocytes and asexual schizonts in less than 12 h without affecting uninfected red blood cells (RBCs). Ring stage parasites are cleared by 24 h. Within an hour of drug treatment, 40% of the normally crescent-shaped gametocytes round up and become spherical. The number of round gametocytes increases to >60% by 2 h, even before a change in membrane potential as monitored by MitoProbe DiIC1 (5) is detectable. Maduramicin is not preferentially taken up by gametocyte-infected RBCs compared to uninfected RBCs, suggesting that gametocytes are more sensitive to alterations in cation concentration than RBCs. Moreover, the addition of 15.6 nM maduramicin enhanced the gametocytocidal activity of the pyrazoleamide PA21A050, which is a promising new antimalarial candidate associated with an increase in intracellular Na(+) concentration that is proposed to be due to inhibition of PfATP4, a putative Na(+) pump. These results underscore the importance of cation homeostasis in sexual as well as asexual intraerythrocytic-stage P. falciparum parasites and the potential of targeting this pathway for drug development.
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109
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Approaches for the vaccination and treatment of Neospora caninum infections in mice and ruminant models. Parasitology 2015; 143:245-59. [PMID: 26626124 DOI: 10.1017/s0031182015001596] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Neospora caninum is a leading cause of abortion in cattle, and is thus an important veterinary health problem of high economic significance. Vaccination has been considered a viable strategy to prevent bovine neosporosis. Different approaches have been investigated, and to date the most promising results have been achieved with live-attenuated vaccines. Subunit vaccines have also been studied, and most of them represented components that are functionally involved in (i) the physical interaction between the parasite and its host cell during invasion or (ii) tachyzoite-to-bradyzoite stage conversion. Drugs have been considered as an option to limit the effects of vertical transmission of N. caninum. Promising results with a small panel of compounds in small laboratory animal models indicate the potential value of a chemotherapeutical approach for the prevention of neosporosis in ruminants. For both, vaccines and drugs, the key for success in preventing vertical transmission lies in the application of bioactive compounds that limit parasite proliferation and dissemination, without endangering the developing fetus not only during an exogenous acute infection but also during recrudescence of a chronic infection. In this review, the current status of vaccine and drug development is presented and novel strategies against neosporosis are discussed.
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110
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Deng X, Duffy SP, Myrand-Lapierre ME, Matthews K, Santoso AT, Du YL, Ryan KS, Ma H. Reduced deformability of parasitized red blood cells as a biomarker for anti-malarial drug efficacy. Malar J 2015; 14:428. [PMID: 26520795 PMCID: PMC4628286 DOI: 10.1186/s12936-015-0957-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/21/2015] [Indexed: 11/28/2022] Open
Abstract
Background Malaria remains a challenging and fatal infectious disease in developing nations and the urgency for the development of new drugs is even greater due to the rapid spread of anti-malarial drug resistance. While numerous parasite genetic, protein and metabolite biomarkers have been proposed for testing emerging anti-malarial compounds, they do not universally correspond with drug efficacy. The biophysical character of parasitized cells is a compelling alternative to these conventional biomarkers because parasitized erythrocytes become specifically rigidified and this effect is potentiated by anti-malarial compounds, such as chloroquine and artesunate. This biophysical biomarker is particularly relevant because of the mechanistic link between cell deformability and enhanced splenic clearance of parasitized erythrocytes. Methods Recently a microfluidic mechanism, called the multiplexed fluidic plunger that provides sensitive and rapid measurement of single red blood cell deformability was developed. Here it was systematically used to evaluate the deformability changes of late-stage trophozoite-infected red blood cells (iRBCs) after treatment with established clinical and pre-clinical anti-malarial compounds. Results It was found that rapid and specific iRBC rigidification was a universal outcome of all but one of these drug treatments. The greatest change in iRBC rigidity was observed for (+)-SJ733 and NITD246 spiroindolone compounds, which target the Plasmodium falciparum cation-transporting ATPase ATP4. As a proof-of-principle, compounds of the bisindole alkaloid class were screened, where cladoniamide A was identified based on rigidification of iRBCs and was found to have previously unreported anti-malarial activity with an IC50 lower than chloroquine. Conclusion These results demonstrate that rigidification of iRBCs may be used as a biomarker for anti-malarial drug efficacy, as well as for new drug screening. The novel anti-malarial properties of cladoniamide A were revealed in a proof-of-principle drug screen. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0957-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiaoyan Deng
- Department of Mechanical Engineering, University of British Columbia, 2054-6250 Applied Science Lane, Vancouver, BC, V6T 1Z4, Canada.
| | - Simon P Duffy
- Department of Mechanical Engineering, University of British Columbia, 2054-6250 Applied Science Lane, Vancouver, BC, V6T 1Z4, Canada.
| | - Marie-Eve Myrand-Lapierre
- Department of Mechanical Engineering, University of British Columbia, 2054-6250 Applied Science Lane, Vancouver, BC, V6T 1Z4, Canada.
| | - Kerryn Matthews
- Department of Mechanical Engineering, University of British Columbia, 2054-6250 Applied Science Lane, Vancouver, BC, V6T 1Z4, Canada.
| | - Aline Teresa Santoso
- Department of Mechanical Engineering, University of British Columbia, 2054-6250 Applied Science Lane, Vancouver, BC, V6T 1Z4, Canada.
| | - Yi-Ling Du
- Department of Chemistry, University of British Columbia, Vancouver, BC, Canada.
| | - Katherine S Ryan
- Department of Chemistry, University of British Columbia, Vancouver, BC, Canada.
| | - Hongshen Ma
- Department of Mechanical Engineering, University of British Columbia, 2054-6250 Applied Science Lane, Vancouver, BC, V6T 1Z4, Canada. .,Department of Urologic Science, University of British Columbia, Vancouver, BC, Canada. .,Vancouver Prostate Centre, Vancouver General Hospital, Vancouver, BC, Canada.
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111
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Bürstner N, Roggo S, Ostermann N, Blank J, Delmas C, Freuler F, Gerhartz B, Hinniger A, Hoepfner D, Liechty B, Mihalic M, Murphy J, Pistorius D, Rottmann M, Thomas JR, Schirle M, Schmitt EK. Gift from Nature: Cyclomarin A Kills Mycobacteria and Malaria Parasites by Distinct Modes of Action. Chembiochem 2015; 16:2433-6. [DOI: 10.1002/cbic.201500472] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Nathalie Bürstner
- Novartis Institutes for BioMedical Research; Novartis Campus 4056 Basel Switzerland
| | - Silvio Roggo
- Novartis Institutes for BioMedical Research; Novartis Campus 4056 Basel Switzerland
| | - Nils Ostermann
- Novartis Institutes for BioMedical Research; Novartis Campus 4056 Basel Switzerland
| | - Jutta Blank
- Novartis Institutes for BioMedical Research; Novartis Campus 4056 Basel Switzerland
| | - Cecile Delmas
- Novartis Institutes for BioMedical Research; Novartis Campus 4056 Basel Switzerland
| | - Felix Freuler
- Novartis Institutes for BioMedical Research; Novartis Campus 4056 Basel Switzerland
| | - Bernd Gerhartz
- Novartis Institutes for BioMedical Research; Novartis Campus 4056 Basel Switzerland
| | - Alexandra Hinniger
- Novartis Institutes for BioMedical Research; Novartis Campus 4056 Basel Switzerland
| | - Dominic Hoepfner
- Novartis Institutes for BioMedical Research; Novartis Campus 4056 Basel Switzerland
| | - Brigitta Liechty
- Novartis Institutes for BioMedical Research; Novartis Campus 4056 Basel Switzerland
| | - Manuel Mihalic
- Novartis Institutes for BioMedical Research; Novartis Campus 4056 Basel Switzerland
| | - Jason Murphy
- Novartis Institutes for BioMedical Research Inc; 250 Massachusetts Avenue Cambridge MA 02139 USA
| | - Dominik Pistorius
- Novartis Institutes for BioMedical Research; Novartis Campus 4056 Basel Switzerland
| | - Matthias Rottmann
- Swiss Tropical and Public Health Institute; Socinstrasse 57 4051 Basel Switzerland
| | - Jason R. Thomas
- Novartis Institutes for BioMedical Research Inc; 250 Massachusetts Avenue Cambridge MA 02139 USA
| | - Markus Schirle
- Novartis Institutes for BioMedical Research Inc; 250 Massachusetts Avenue Cambridge MA 02139 USA
| | - Esther K. Schmitt
- Novartis Institutes for BioMedical Research; Novartis Campus 4056 Basel Switzerland
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112
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Natural products as probes in pharmaceutical research. J Ind Microbiol Biotechnol 2015; 43:249-60. [PMID: 26438431 DOI: 10.1007/s10295-015-1691-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 09/16/2015] [Indexed: 10/23/2022]
Abstract
From the start of the pharmaceutical research natural products played a key role in drug discovery and development. Over time many discoveries of fundamental new biology were triggered by the unique biological activity of natural products. Unprecedented chemical structures, novel chemotypes, often pave the way to investigate new biology and to explore new pathways and targets. This review summarizes the recent results in the area with a focus on research done in the laboratories of Novartis Institutes for BioMedical Research. We aim to put the technological advances in target identification techniques in the context to the current revival of phenotypic screening and the increasingly complex biological questions related to drug discovery.
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113
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Sitsel O, Grønberg C, Autzen HE, Wang K, Meloni G, Nissen P, Gourdon P. Structure and Function of Cu(I)- and Zn(II)-ATPases. Biochemistry 2015; 54:5673-83. [PMID: 26132333 DOI: 10.1021/acs.biochem.5b00512] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Copper and zinc are micronutrients essential for the function of many enzymes while also being toxic at elevated concentrations. Cu(I)- and Zn(II)-transporting P-type ATPases of subclass 1B are of key importance for the homeostasis of these transition metals, allowing ion transport across cellular membranes at the expense of ATP. Recent biochemical studies and crystal structures have significantly improved our understanding of the transport mechanisms of these proteins, but many details about their structure and function remain elusive. Here we compare the Cu(I)- and Zn(II)-ATPases, scrutinizing the molecular differences that allow transport of these two distinct metal types, and discuss possible future directions of research in the field.
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Affiliation(s)
- Oleg Sitsel
- Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, Department of Molecular Biology and Genetics, Aarhus University , Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
| | - Christina Grønberg
- Department of Biomedical Sciences, University of Copenhagen , Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
| | - Henriette Elisabeth Autzen
- Department of Biomedical Sciences, University of Copenhagen , Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
| | - Kaituo Wang
- Department of Biomedical Sciences, University of Copenhagen , Blegdamsvej 3B, DK-2200 Copenhagen, Denmark
| | - Gabriele Meloni
- Division of Chemistry and Chemical Engineering and Howard Hughes Medical Institute, California Institute of Technology , Pasadena, California 91125, United States
| | - Poul Nissen
- Centre for Membrane Pumps in Cells and Disease (PUMPkin), Danish National Research Foundation, Department of Molecular Biology and Genetics, Aarhus University , Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark
| | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen , Blegdamsvej 3B, DK-2200 Copenhagen, Denmark.,Department of Experimental Medical Science, Lund University , Sölvegatan 19, SE-221 84 Lund, Sweden
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Spillman NJ, Kirk K. The malaria parasite cation ATPase PfATP4 and its role in the mechanism of action of a new arsenal of antimalarial drugs. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2015; 5:149-62. [PMID: 26401486 PMCID: PMC4559606 DOI: 10.1016/j.ijpddr.2015.07.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 07/03/2015] [Accepted: 07/08/2015] [Indexed: 11/28/2022]
Abstract
The intraerythrocytic malaria parasite, Plasmodium falciparum, maintains a low cytosolic Na(+) concentration and the plasma membrane P-type cation translocating ATPase 'PfATP4' has been implicated as playing a key role in this process. PfATP4 has been the subject of significant attention in recent years as mutations in this protein confer resistance to a growing number of new antimalarial compounds, including the spiroindolones, the pyrazoles, the dihydroisoquinolones, and a number of the antimalarial agents in the Medicines for Malaria Venture's 'Malaria Box'. On exposure of parasites to these compounds there is a rapid disruption of cytosolic Na(+). Whether, and if so how, such chemically distinct compounds interact with PfATP4, and how such interactions lead to parasite death, is not yet clear. The fact that multiple different chemical classes have converged upon PfATP4 highlights its significance as a potential target for new generation antimalarial agents. A spiroindolone (KAE609, now known as cipargamin) has progressed through Phase I and IIa clinical trials with favourable results. In this review we consider the physiological role of PfATP4, summarise the current repertoire of antimalarial compounds for which PfATP4 is implicated in their mechanism of action, and provide an outlook on translation from target identification in the laboratory to patient treatment in the field.
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Affiliation(s)
- Natalie Jane Spillman
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 2601, Australia ; Department of Medicine (Infectious Diseases), Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Kiaran Kirk
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 2601, Australia
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115
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Abstract
The development of resistance to existing antimicrobials has created a threat to human health that is not being addressed through our current drug pipeline. Limitations with the use of commercial vendor libraries and natural products have created a need for new types of small molecules to be screened in antimicrobial assays. Diversity oriented synthesis (DOS) is a strategy for the efficient generation of compound collections with a high degree of structural diversity. Diversity-oriented synthesis molecules occupy the middle ground of both complexity and efficiency of synthesis between natural products and commercial libraries. In this review we focus upon the use of diversity-oriented synthesis compound collections for the discovery of new antimicrobial agents.
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116
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Ang MLT, Murima P, Pethe K. Next-generation antimicrobials: from chemical biology to first-in-class drugs. Arch Pharm Res 2015; 38:1702-17. [PMID: 26259630 PMCID: PMC4567591 DOI: 10.1007/s12272-015-0645-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 07/29/2015] [Indexed: 01/11/2023]
Abstract
The global emergence of multi-drug resistant bacteria invokes an urgent and imperative necessity for the identification of novel antimicrobials. The general lack of success in progressing novel chemical entities from target-based drug screens have prompted calls for radical and innovative approaches for drug discovery. Recent developments in chemical biology and target deconvolution strategies have revived interests in the utilization of whole-cell phenotypic screens and resulted in several success stories for the discovery and development novel drug candidates and target pathways. In this review, we present and discuss recent chemical biology approaches focusing on the discovery of novel targets and new lead molecules for the treatment of human bacterial and protozoan infections.
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Affiliation(s)
- Michelle Lay Teng Ang
- Lee Kong Chian School of Medicine and School of Biological Sciences, Nanyang Technological University, 30 Biopolis Street, #B2-15a, Singapore, 138671, Singapore.
| | - Paul Murima
- Global Health Institute, Swiss Federal Institute of Technology in Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Kevin Pethe
- Lee Kong Chian School of Medicine and School of Biological Sciences, Nanyang Technological University, 30 Biopolis Street, #B2-15a, Singapore, 138671, Singapore.
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117
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Cui L, Mharakurwa S, Ndiaye D, Rathod PK, Rosenthal PJ. Antimalarial Drug Resistance: Literature Review and Activities and Findings of the ICEMR Network. Am J Trop Med Hyg 2015; 93:57-68. [PMID: 26259943 PMCID: PMC4574275 DOI: 10.4269/ajtmh.15-0007] [Citation(s) in RCA: 180] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 04/27/2015] [Indexed: 11/07/2022] Open
Abstract
Antimalarial drugs are key tools for the control and elimination of malaria. Recent decreases in the global malaria burden are likely due, in part, to the deployment of artemisinin-based combination therapies. Therefore, the emergence and potential spread of artemisinin-resistant parasites in southeast Asia and changes in sensitivities to artemisinin partner drugs have raised concerns. In recognition of this urgent threat, the International Centers of Excellence for Malaria Research (ICEMRs) are closely monitoring antimalarial drug efficacy and studying the mechanisms underlying drug resistance. At multiple sentinel sites of the global ICEMR network, research activities include clinical studies to track the efficacies of antimalarial drugs, ex vivo/in vitro assays to measure drug susceptibilities of parasite isolates, and characterization of resistance-mediating parasite polymorphisms. Taken together, these efforts offer an increasingly comprehensive assessment of the efficacies of antimalarial therapies, and enable us to predict the emergence of drug resistance and to guide local antimalarial drug policies. Here we briefly review worldwide antimalarial drug resistance concerns, summarize research activities of the ICEMRs related to drug resistance, and assess the global impacts of the ICEMR programs.
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Affiliation(s)
- Liwang Cui
- *Address correspondence to Liwang Cui, Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA 16802, E-mail: or Philip J. Rosenthal, Department of Medicine, Box 0811, University of California, San Francisco, CA 94110. E-mail:
| | | | | | | | - Philip J. Rosenthal
- *Address correspondence to Liwang Cui, Department of Entomology, Pennsylvania State University, 501 ASI Building, University Park, PA 16802, E-mail: or Philip J. Rosenthal, Department of Medicine, Box 0811, University of California, San Francisco, CA 94110. E-mail:
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118
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Zhang R, Suwanarusk R, Malleret B, Cooke BM, Nosten F, Lau YL, Dao M, Lim CT, Renia L, Tan KSW, Russell B. A Basis for Rapid Clearance of Circulating Ring-Stage Malaria Parasites by the Spiroindolone KAE609. J Infect Dis 2015; 213:100-4. [PMID: 26136472 PMCID: PMC4676544 DOI: 10.1093/infdis/jiv358] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 06/21/2015] [Indexed: 11/30/2022] Open
Abstract
Recent clinical trials revealed a surprisingly rapid clearance of red blood cells (RBCs) infected with malaria parasites by the spiroindolone KAE609. Here, we show that ring-stage parasite–infected RBCs exposed to KAE609 become spherical and rigid, probably through osmotic dysregulation consequent to the disruption of the parasite's sodium efflux pump (adenosine triphosphate 4). We also show that this peculiar drug effect is likely to cause accelerated splenic clearance of the rheologically impaired Plasmodium vivax– and Plasmodium falciparum–infected RBCs.
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Affiliation(s)
- Rou Zhang
- Department of Microbiology, Yong Loo Lin School of Medicine
| | - Rossarin Suwanarusk
- Singapore Immunology Network (SIgN), Agency for Science Technology and Research (A*STAR), Biopolis
| | - Benoit Malleret
- Department of Microbiology, Yong Loo Lin School of Medicine Singapore Immunology Network (SIgN), Agency for Science Technology and Research (A*STAR), Biopolis
| | - Brian M Cooke
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Francois Nosten
- Shoklo Malaria Research Unit, Mae Sot, Tak Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
| | - Yee-Ling Lau
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur
| | - Ming Dao
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge
| | - Chwee Teck Lim
- Biomedical Engineering, National University of Singapore
| | - Laurent Renia
- Singapore Immunology Network (SIgN), Agency for Science Technology and Research (A*STAR), Biopolis
| | | | - Bruce Russell
- Department of Microbiology, Yong Loo Lin School of Medicine
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119
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Diagana TT. Supporting malaria elimination with 21st century antimalarial agent drug discovery. Drug Discov Today 2015; 20:1265-70. [PMID: 26103616 DOI: 10.1016/j.drudis.2015.06.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 05/27/2015] [Accepted: 06/15/2015] [Indexed: 12/26/2022]
Abstract
The burden of malaria has been considerably reduced over recent years. However, to achieve disease elimination, drug discovery for the next generation needs to focus on blocking disease transmission and on targeting the liver-stage forms of the parasite. Properties of the 'ideal' new antimalarial drug and the key scientific and technological advances that have led to recent progress in antimalarial drug discovery are reviewed. Using these advances, Novartis has built a robust pipeline of next-generation antimalarials. The preclinical and clinical development of two candidate drugs: KAE609 and KAF156, provide a framework for the path to breakthrough treatments that could be taking us a step closer to the vision of malaria elimination.
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Affiliation(s)
- Thierry T Diagana
- Novartis Institute for Tropical Diseases, 10 Biopolis Road, #05-01 Chromos, Singapore 138670, Singapore.
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120
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Drug discovery for the developing world: progress at the Novartis Institute for Tropical Diseases. Nat Rev Drug Discov 2015; 14:442-4. [DOI: 10.1038/nrd4001-c1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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121
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Abstract
Despite substantial scientific progress over the past two decades, malaria remains a worldwide burden that causes hundreds of thousands of deaths every year. New, affordable and safe drugs are required to overcome increasing resistance against artemisinin-based treatments, treat vulnerable populations, interrupt the parasite life cycle by blocking transmission to the vectors, prevent infection and target malaria species that transiently remain dormant in the liver. In this Review, we discuss how the antimalarial drug discovery pipeline has changed over the past 10 years, grouped by the various target compound or product profiles, to assess progress and gaps, and to recommend priorities.
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122
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Kumar S, Kumari R, Pandey R. New insight-guided approaches to detect, cure, prevent and eliminate malaria. PROTOPLASMA 2015; 252:717-753. [PMID: 25323622 DOI: 10.1007/s00709-014-0697-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 09/01/2014] [Indexed: 06/04/2023]
Abstract
New challenges posed by the development of resistance against artemisinin-based combination therapies (ACTs) as well as previous first-line therapies, and the continuing absence of vaccine, have given impetus to research in all areas of malaria control. This review portrays the ongoing progress in several directions of malaria research. The variants of RTS,S and apical membrane antigen 1 (AMA1) are being developed and test adapted as multicomponent and multistage malaria control vaccines, while many other vaccine candidates and methodologies to produce antigens are under experimentation. To track and prevent the spread of artemisinin resistance from Southeast Asia to other parts of the world, rolling circle-enhanced enzyme activity detection (REEAD), a time- and cost-effective malaria diagnosis in field conditions, and a DNA marker associated with artemisinin resistance have become available. Novel mosquito repellents and mosquito trapping and killing techniques much more effective than the prevalent ones are undergoing field testing. Mosquito lines stably infected with their symbiotic wild-type or genetically engineered bacteria that kill sympatric malaria parasites are being constructed and field tested for stopping malaria transmission. A complementary approach being pursued is the addition of ivermectin-like drug molecules to ACTs to cure malaria and kill mosquitoes. Experiments are in progress to eradicate malaria mosquito by making it genetically male sterile. High-throughput screening procedures are being developed and used to discover molecules that possess long in vivo half life and are active against liver and blood stages for the fast cure of malaria symptoms caused by simple or relapsing and drug-sensitive and drug-resistant types of varied malaria parasites, can stop gametocytogenesis and sporogony and could be given in one dose. Target-based antimalarial drug designing has begun. Some of the putative next-generation antimalarials that possess in their scaffold structure several of the desired properties of malaria cure and control are exemplified by OZ439, NITD609, ELQ300 and tafenoquine that are already undergoing clinical trials, and decoquinate, usnic acid, torin-2, ferroquine, WEHI-916, MMV396749 and benzothiophene-type N-myristoyltransferase (NMT) inhibitors, which are candidates for future clinical usage. Among these, NITD609, ELQ300, decoquinate, usnic acid, torin-2 and NMT inhibitors not only cure simple malaria and are prophylactic against simple malaria, but they also cure relapsing malaria.
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Affiliation(s)
- Sushil Kumar
- SKA Institution for Research, Education and Development (SKAIRED), 4/11 SarvPriya Vihar, New Delhi, 110016, India,
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123
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A lactate and formate transporter in the intraerythrocytic malaria parasite, Plasmodium falciparum. Nat Commun 2015; 6:6721. [PMID: 25823844 DOI: 10.1038/ncomms7721] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 02/23/2015] [Indexed: 12/24/2022] Open
Abstract
The intraerythrocytic malaria parasite relies primarily on glycolysis to fuel its rapid growth and reproduction. The major byproduct of this metabolism, lactic acid, is extruded into the external medium. In this study, we show that the human malaria parasite Plasmodium falciparum expresses at its surface a member of the microbial formate-nitrite transporter family (PfFNT), which, when expressed in Xenopus laevis oocytes, transports both formate and lactate. The transport characteristics of PfFNT in oocytes (pH-dependence, inhibitor-sensitivity and kinetics) are similar to those of the transport of lactate and formate across the plasma membrane of mature asexual-stage P. falciparum trophozoites, consistent with PfFNT playing a major role in the efflux of lactate and hence in the energy metabolism of the intraerythrocytic parasite.
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124
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Flannery EL, McNamara CW, Kim SW, Kato TS, Li F, Teng CH, Gagaring K, Manary MJ, Barboa R, Meister S, Kuhen K, Vinetz JM, Chatterjee AK, Winzeler EA. Mutations in the P-type cation-transporter ATPase 4, PfATP4, mediate resistance to both aminopyrazole and spiroindolone antimalarials. ACS Chem Biol 2015; 10:413-20. [PMID: 25322084 PMCID: PMC4340351 DOI: 10.1021/cb500616x] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
![]()
Aminopyrazoles are a new class of
antimalarial compounds identified
in a cellular antiparasitic screen with potent activity against Plasmodium falciparum asexual and sexual stage parasites.
To investigate their unknown mechanism of action and thus identify
their target, we cultured parasites in the presence of a representative
member of the aminopyrazole series, GNF-Pf4492, to select for resistance.
Whole genome sequencing of three resistant lines showed that each
had acquired independent mutations in a P-type cation-transporter
ATPase, PfATP4 (PF3D7_1211900), a protein implicated as the novel Plasmodium spp. target of another, structurally unrelated,
class of antimalarials called the spiroindolones and characterized
as an important sodium transporter of the cell. Similarly to the spiroindolones,
GNF-Pf4492 blocks parasite transmission to mosquitoes and disrupts
intracellular sodium homeostasis. Our data demonstrate that PfATP4
plays a critical role in cellular processes, can be inhibited by two
distinct antimalarial pharmacophores, and supports the recent observations
that PfATP4 is a critical antimalarial target.
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Affiliation(s)
| | - Case W. McNamara
- The Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, United States
| | | | - Tomoyo Sakata Kato
- The Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, United States
| | | | | | - Kerstin Gagaring
- The Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, United States
| | | | - Rachel Barboa
- The Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, United States
| | | | - Kelli Kuhen
- The Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, United States
| | | | - Arnab K. Chatterjee
- The Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, United States
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Held J, Jeyaraj S, Kreidenweiss A. Antimalarial compounds in Phase II clinical development. Expert Opin Investig Drugs 2015; 24:363-82. [PMID: 25563531 DOI: 10.1517/13543784.2015.1000483] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Malaria is a major health problem in endemic countries and chemotherapy remains the most important tool in combating it. Treatment options are limited and essentially rely on a single drug class - the artemisinins. Efforts are ongoing to restrict the evolving threat of artemisinin resistance but declining sensitivity has been reported. Fueled by the ambitious aim of malaria eradication, novel antimalarial compounds, with improved properties, are now in the progressive phase of drug development. AREAS COVERED Herein, the authors describe antimalarial compounds currently in Phase II clinical development and present the results of these investigations. EXPERT OPINION Thanks to recent efforts, a number of promising antimalarial compounds are now in the pipeline. First safety data have been generated for all of these candidates, although their efficacy as antimalarials is still unclear for most of them. Of particular note are KAE609, KAF156 and DSM265, which are of chemical scaffolds new to malaria chemotherapy and would truly diversify antimalarial options. Apart from SAR97276, which also has a novel chemical scaffold that has had its development stopped, all other compounds in the pipeline belong to already known substance classes, which have been chemically modified. At this moment in time, there is not one standout compound that will revolutionize malaria treatment but several compounds that will add to its control in the future.
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Affiliation(s)
- Jana Held
- Institut für Tropenmedizin, Eberhard Karls Universität , Wilhelmstraße 27, D-72074 Tübingen , Germany +49 7071 29 85569 ; +49 7071 295189 ;
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Arulananda Babu S, Padmavathi R, Ahmad Aslam N, Rajkumar V. Recent Developments on the Synthesis and Applications of Natural Products-Inspired Spirooxindole Frameworks. STUDIES IN NATURAL PRODUCTS CHEMISTRY 2015. [DOI: 10.1016/b978-0-444-63462-7.00008-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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127
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Pharmacokinetic-pharmacodynamic analysis of spiroindolone analogs and KAE609 in a murine malaria model. Antimicrob Agents Chemother 2014; 59:1200-10. [PMID: 25487807 PMCID: PMC4335872 DOI: 10.1128/aac.03274-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Limited information is available on the pharmacokinetic (PK) and pharmacodynamic (PD) parameters driving the efficacy of antimalarial drugs. Our objective in this study was to determine dose-response relationships of a panel of related spiroindolone analogs and identify the PK-PD index that correlates best with the efficacy of KAE609, a selected class representative. The dose-response efficacy studies were conducted in the Plasmodium berghei murine malaria model, and the relationship between dose and efficacy (i.e., reduction in parasitemia) was examined. All spiroindolone analogs studied displayed a maximum reduction in parasitemia, with 90% effective dose (ED90) values ranging between 6 and 38 mg/kg of body weight. Further, dose fractionation studies were conducted for KAE609, and the relationship between PK-PD indices and efficacy was analyzed. The PK-PD indices were calculated using the in vitro potency against P. berghei (2× the 99% inhibitory concentration [IC99]) as a threshold (TRE). The percentage of the time in which KAE609 plasma concentrations remained at >2× the IC99 within 48 h (%T>TRE) and the area under the concentration-time curve from 0 to 48 h (AUC0–48)/TRE ratio correlated well with parasite reduction (R2 = 0.97 and 0.95, respectively) but less so for the maximum concentration of drug in serum (Cmax)/TRE ratio (R2 = 0.88). The present results suggest that for KAE609 and, supposedly, for its analogs, the dosing regimens covering a T>TRE of 100%, AUC0–48/TRE ratio of 587, and a Cmax/TRE ratio of 30 are likely to result in the maximum reduction in parasitemia in the P. berghei malaria mouse model. This information could be used to prioritize analogs within the same class of compounds and contribute to the design of efficacy studies, thereby facilitating early drug discovery and lead optimization programs.
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128
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(+)-SJ733, a clinical candidate for malaria that acts through ATP4 to induce rapid host-mediated clearance of Plasmodium. Proc Natl Acad Sci U S A 2014; 111:E5455-62. [PMID: 25453091 DOI: 10.1073/pnas.1414221111] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Drug discovery for malaria has been transformed in the last 5 years by the discovery of many new lead compounds identified by phenotypic screening. The process of developing these compounds as drug leads and studying the cellular responses they induce is revealing new targets that regulate key processes in the Plasmodium parasites that cause malaria. We disclose herein that the clinical candidate (+)-SJ733 acts upon one of these targets, ATP4. ATP4 is thought to be a cation-transporting ATPase responsible for maintaining low intracellular Na(+) levels in the parasite. Treatment of parasitized erythrocytes with (+)-SJ733 in vitro caused a rapid perturbation of Na(+) homeostasis in the parasite. This perturbation was followed by profound physical changes in the infected cells, including increased membrane rigidity and externalization of phosphatidylserine, consistent with eryptosis (erythrocyte suicide) or senescence. These changes are proposed to underpin the rapid (+)-SJ733-induced clearance of parasites seen in vivo. Plasmodium falciparum ATPase 4 (pfatp4) mutations that confer resistance to (+)-SJ733 carry a high fitness cost. The speed with which (+)-SJ733 kills parasites and the high fitness cost associated with resistance-conferring mutations appear to slow and suppress the selection of highly drug-resistant mutants in vivo. Together, our data suggest that inhibitors of PfATP4 have highly attractive features for fast-acting antimalarials to be used in the global eradication campaign.
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129
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Vaidya AB, Morrisey JM, Zhang Z, Das S, Daly TM, Otto TD, Spillman NJ, Wyvratt M, Siegl P, Marfurt J, Wirjanata G, Sebayang BF, Price RN, Chatterjee A, Nagle A, Stasiak M, Charman SA, Angulo-Barturen I, Ferrer S, Belén Jiménez-Díaz M, Martínez MS, Gamo FJ, Avery VM, Ruecker A, Delves M, Kirk K, Berriman M, Kortagere S, Burrows J, Fan E, Bergman LW. Pyrazoleamide compounds are potent antimalarials that target Na+ homeostasis in intraerythrocytic Plasmodium falciparum. Nat Commun 2014; 5:5521. [PMID: 25422853 PMCID: PMC4263321 DOI: 10.1038/ncomms6521] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Accepted: 10/09/2014] [Indexed: 01/01/2023] Open
Abstract
The quest for new antimalarial drugs, especially those with novel modes of action, is essential in the face of emerging drug-resistant parasites. Here we describe a new chemical class of molecules, pyrazoleamides, with potent activity against human malaria parasites and showing remarkably rapid parasite clearance in an in vivo model. Investigations involving pyrazoleamide-resistant parasites, whole-genome sequencing and gene transfers reveal that mutations in two proteins, a calcium-dependent protein kinase (PfCDPK5) and a P-type cation-ATPase (PfATP4), are necessary to impart full resistance to these compounds. A pyrazoleamide compound causes a rapid disruption of Na+ regulation in blood-stage Plasmodium falciparum parasites. Similar effect on Na+ homeostasis was recently reported for spiroindolones, which are antimalarials of a chemical class quite distinct from pyrazoleamides. Our results reveal that disruption of Na+ homeostasis in malaria parasites is a promising mode of antimalarial action mediated by at least two distinct chemical classes. Novel antimalarial drugs are urgently needed to combat parasite drug resistance. Here, Vaidya et al. describe a new chemical class of potent antimalarial compounds that act by disrupting the parasite's sodium homeostasis.
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Affiliation(s)
- Akhil B Vaidya
- Department of Microbiology and Immunology, Center for Molecular Parasitology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 190129, USA
| | - Joanne M Morrisey
- Department of Microbiology and Immunology, Center for Molecular Parasitology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 190129, USA
| | - Zhongsheng Zhang
- Department of Biochemistry, University of Washington, Box 357350, Seattle, Washington 98195, USA
| | - Sudipta Das
- Department of Microbiology and Immunology, Center for Molecular Parasitology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 190129, USA
| | - Thomas M Daly
- Department of Microbiology and Immunology, Center for Molecular Parasitology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 190129, USA
| | - Thomas D Otto
- Wellcome Trust Sanger Institute, Hinxton, Cambridge CB101SA, UK
| | - Natalie J Spillman
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - Matthew Wyvratt
- Medicines for Malaria Venture, PO Box 1826, 20Rt de Pr-Bois, Geneva 15 1215, Switzerland
| | - Peter Siegl
- Medicines for Malaria Venture, PO Box 1826, 20Rt de Pr-Bois, Geneva 15 1215, Switzerland
| | - Jutta Marfurt
- Division of Global and Tropical Health, Menzies School of Health Research and Charles Darwin University, PO Box 41096, Casuarina, Northern Territory 0811, Australia
| | - Grennady Wirjanata
- Division of Global and Tropical Health, Menzies School of Health Research and Charles Darwin University, PO Box 41096, Casuarina, Northern Territory 0811, Australia
| | - Boni F Sebayang
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta 10430, Indonesia
| | - Ric N Price
- 1] Division of Global and Tropical Health, Menzies School of Health Research and Charles Darwin University, PO Box 41096, Casuarina, Northern Territory 0811, Australia [2] Nuffield Department of Clinical Medicine, Centre for Tropical Medicine, University of Oxford, Oxford OX3 7LJ, UK
| | - Arnab Chatterjee
- Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121, USA
| | - Advait Nagle
- Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, California 92121, USA
| | - Marcin Stasiak
- Department of Biochemistry, University of Washington, Box 357350, Seattle, Washington 98195, USA
| | - Susan A Charman
- Center for Drug Candidate Optimisation, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
| | - Iñigo Angulo-Barturen
- GlaxoSmithKline, Malaria Support Group, Calle Severo Ochoa 2, Tres Cantos 28760, Spain
| | - Santiago Ferrer
- GlaxoSmithKline, Malaria Support Group, Calle Severo Ochoa 2, Tres Cantos 28760, Spain
| | | | - María Santos Martínez
- GlaxoSmithKline, Malaria Support Group, Calle Severo Ochoa 2, Tres Cantos 28760, Spain
| | - Francisco Javier Gamo
- GlaxoSmithKline, Malaria Support Group, Calle Severo Ochoa 2, Tres Cantos 28760, Spain
| | - Vicky M Avery
- Eskitis Institute, Griffith University, Don Young Road, Nathan, Queensland 4111, Australia
| | - Andrea Ruecker
- Department of Life Sciences, South Kensington Campus, Imperial College, London SW7 2AZ, UK
| | - Michael Delves
- Department of Life Sciences, South Kensington Campus, Imperial College, London SW7 2AZ, UK
| | - Kiaran Kirk
- Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | | | - Sandhya Kortagere
- Department of Microbiology and Immunology, Center for Molecular Parasitology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 190129, USA
| | - Jeremy Burrows
- Medicines for Malaria Venture, PO Box 1826, 20Rt de Pr-Bois, Geneva 15 1215, Switzerland
| | - Erkang Fan
- Department of Biochemistry, University of Washington, Box 357350, Seattle, Washington 98195, USA
| | - Lawrence W Bergman
- Department of Microbiology and Immunology, Center for Molecular Parasitology, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, Pennsylvania 190129, USA
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130
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Affiliation(s)
- David S Barnett
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital , Memphis, Tennessee 38105, United States
| | - R Kiplin Guy
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital , Memphis, Tennessee 38105, United States
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131
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Webster WAJ, McFadden GI. From the genome to the phenome: tools to understand the basic biology of Plasmodium falciparum. J Eukaryot Microbiol 2014; 61:655-71. [PMID: 25227912 DOI: 10.1111/jeu.12176] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/01/2014] [Accepted: 09/02/2014] [Indexed: 11/30/2022]
Abstract
Malaria plagues one out of every 30 humans and contributes to almost a million deaths, and the problem could worsen. Our current therapeutic options are compromised by emerging resistance by the parasite to our front line drugs. It is thus imperative to better understand the basic biology of the parasite and develop novel drugs to stem this disease. The most facile approach to analyse a gene's function is to remove it from the genome or inhibit its activity. Although genetic manipulation of the human malaria parasite Plasmodium falciparum is a relatively standard procedure, there is no optimal method to perturb genes essential to the intraerythrocytic development cycle--the part of the life cycle that produces the clinical manifestation of malaria. This is a severe impediment to progress because the phenotype we wish to study is exactly the one that is so elusive. In the absence of any utilitarian way to conditionally delete essential genes, we are prevented from investigating the parasite's most vulnerable points. This review aims to focus on the development of tools identifying essential genes of P. falciparum and our ability to elicit phenotypic mutation.
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Affiliation(s)
- Wesley A J Webster
- Centre for Regional and Rural Futures, School of Life and Environmental Sciences, Deakin University, Burwood, 3125, Victoria, Australia; Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Melbourne, 3010, Victoria, Australia
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132
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Lehane AM, Ridgway MC, Baker E, Kirk K. Diverse chemotypes disrupt ion homeostasis in the Malaria parasite. Mol Microbiol 2014; 94:327-39. [PMID: 25145582 DOI: 10.1111/mmi.12765] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2014] [Indexed: 01/09/2023]
Abstract
The antimalarial spiroindolones disrupt Plasmodium falciparum Na(+) regulation and induce an alkalinization of the parasite cytosol. It has been proposed that they do so by inhibiting PfATP4, a parasite plasma membrane P-type ATPase postulated to export Na(+) and import H(+) equivalents. Here, we screened the 400 antiplasmodial compounds of the open access 'Malaria Box' for their effects on parasite ion regulation. Twenty eight compounds affected parasite Na(+) and pH regulation in a manner consistent with PfATP4 inhibition. Six of these, with chemically diverse structures, were selected for further analysis. All six showed reduced antiplasmodial activity against spiroindolone-resistant parasites carrying mutations in pfatp4. We exposed parasites to incrementally increasing concentrations of two of the six compounds and in both cases obtained resistant parasites with mutations in pfatp4. The finding that diverse chemotypes have an apparently similar mechanism of action indicates that PfATP4 may be a significant Achilles' heel for the parasite.
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Affiliation(s)
- Adele M Lehane
- Research School of Biology, Australian National University, Canberra, ACT, 0200, Australia
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133
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A first-in-human randomized, double-blind, placebo-controlled, single- and multiple-ascending oral dose study of novel antimalarial Spiroindolone KAE609 (Cipargamin) to assess its safety, tolerability, and pharmacokinetics in healthy adult volunteers. Antimicrob Agents Chemother 2014; 58:6209-14. [PMID: 25114127 PMCID: PMC4187895 DOI: 10.1128/aac.03393-14] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This first-in-human randomized, double-blind, placebo-controlled, ascending-single and -multiple oral dose study was designed to evaluate the safety, tolerability, and pharmacokinetics in healthy volunteers of KAE609 (cipargamin; formerly NITD609), a spiroindolone now in trials for malaria treatment. It was studied in single-dose cohorts (1 to 300 mg, including one 30-mg food effect cohort) with 4 to 10 subjects in each cohort and in multiple-dose cohorts (10 to 150 mg once daily for 3 days) with 8 subjects in each cohort. The follow-up period was 6 to 8 days post-last dose. Safety and pharmacokinetics were assessed at scheduled time points during the study. Systemic exposure in terms of the area under the concentration-time curve from 0 h extrapolated to infinity (AUC0-∞) increased in a dose-proportional manner over the dose range of 1 to 300 mg. The AUC from time zero to the time of the last quantifiable concentration (AUClast) and the maximum concentration of drug in plasma (Cmax) also increased in an approximately dose-proportional manner. When administered daily for 3 days, the accumulation ratio on day 3 (the AUC from time zero to 24 h postdosing [AUC0-24] on day 3/AUC0-24 on day 1) was in the range of 1.5 to 2 in the studied dose range (10 to 150 mg) and was consistent with an elimination half-life of around 24 h. Urine analysis for unchanged KAE609 revealed negligible amounts (≤0.01%) were excreted renally. The high fat food intake did not affect the extent of KAE609 absorption (AUC); however, the Cmax was reduced by around 27%. KAE609 was tolerated in this study, with transient gastrointestinal and genitourinary adverse events of mild to moderate intensity (semen discoloration, diarrhea, nausea and abdominal discomfort, dizziness and headache, catheter site hematoma). Gastrointestinal and genitourinary adverse events increased with rising doses.
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134
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Affiliation(s)
- Brian Greenwood
- From the London School of Hygiene and Tropical Medicine, London
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135
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White NJ, Pukrittayakamee S, Phyo AP, Rueangweerayut R, Nosten F, Jittamala P, Jeeyapant A, Jain JP, Lefèvre G, Li R, Magnusson B, Diagana TT, Leong FJ. Spiroindolone KAE609 for falciparum and vivax malaria. N Engl J Med 2014; 371:403-10. [PMID: 25075833 PMCID: PMC4143746 DOI: 10.1056/nejmoa1315860] [Citation(s) in RCA: 161] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND KAE609 (cipargamin; formerly NITD609, Novartis Institute for Tropical Diseases) is a new synthetic antimalarial spiroindolone analogue with potent, dose-dependent antimalarial activity against asexual and sexual stages of Plasmodium falciparum. METHODS We conducted a phase 2, open-label study at three centers in Thailand to assess the antimalarial efficacy, safety, and adverse-event profile of KAE609, at a dose of 30 mg per day for 3 days, in two sequential cohorts of adults with uncomplicated P. vivax malaria (10 patients) or P. falciparum malaria (11). The primary end point was the parasite clearance time. RESULTS The median parasite clearance time was 12 hours in each cohort (interquartile range, 8 to 16 hours in patients with P. vivax malaria and 10 to 16 hours in those with P. falciparum malaria). The median half-lives for parasite clearance were 0.95 hours (range, 0.68 to 2.01; interquartile range, 0.85 to 1.14) in the patients with P. vivax malaria and 0.90 hours (range, 0.68 to 1.64; interquartile range, 0.78 to 1.07) in those with P. falciparum malaria. By comparison, only 19 of 5076 patients with P. falciparum malaria (<1%) who were treated with oral artesunate in Southeast Asia had a parasite clearance half-life of less than 1 hour. Adverse events were reported in 14 patients (67%), with nausea being the most common. The adverse events were generally mild and did not lead to any discontinuations of the drug. The mean terminal half-life for the elimination of KAE609 was 20.8 hours (range, 11.3 to 37.6), supporting a once-daily oral dosing regimen. CONCLUSIONS KAE609, at dose of 30 mg daily for 3 days, cleared parasitemia rapidly in adults with uncomplicated P. vivax or P. falciparum malaria. (Funded by Novartis and others; ClinicalTrials.gov number, NCT01524341.).
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Affiliation(s)
- Nicholas J White
- From the Mahidol-Oxford Tropical Medicine Research Unit (N.J.W., F.N., A.J.) and the Department of Clinical Tropical Medicine (S.P., P.J.), Faculty of Tropical Medicine, Mahidol University, Bangkok, and the Shoklo Malaria Research Unit, Faculty of Tropical Medicine, Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University (A.P.P., F.N.), and Mae Sot General Hospital (R.R.), Mae Sot - all in Thailand; the Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom (N.J.W., F.N.); Novartis Healthcare, Hyderabad, India (J.P.J.); Novartis, Basel, Switzerland (G.L., B.M.); Novartis Institute of Biomedical Research, Beijing (R.L.); and Novartis Institute for Tropical Diseases, Singapore (T.T.D., F.J.L.)
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136
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Drug target identification using a trypanosome overexpression library. Antimicrob Agents Chemother 2014; 58:6260-4. [PMID: 25049244 DOI: 10.1128/aac.03338-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Elucidation of molecular targets is very important for lead optimization during the drug development process. We describe a direct method to find targets of antitrypanosomal compounds against Trypanosoma brucei using a trypanosome overexpression library. As proof of concept, we treated the library with difluoromethylornithine and DDD85646 and identified their respective targets, ornithine decarboxylase and N-myristoyltransferase. The overexpression library could be a useful tool to study the modes of action of novel antitrypanosomal drug candidates.
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137
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Njoroge M, Njuguna NM, Mutai P, Ongarora DSB, Smith PW, Chibale K. Recent approaches to chemical discovery and development against malaria and the neglected tropical diseases human African trypanosomiasis and schistosomiasis. Chem Rev 2014; 114:11138-63. [PMID: 25014712 DOI: 10.1021/cr500098f] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
| | | | | | | | - Paul W Smith
- Novartis Institute for Tropical Diseases , Singapore 138670, Singapore
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138
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Abstract
As it grows and replicates within the erythrocytes of its host the malaria parasite takes up nutrients from the extracellular medium, exports metabolites and maintains a tight control over its internal ionic composition. These functions are achieved via membrane transport proteins, integral membrane proteins that mediate the passage of solutes across the various membranes that separate the biochemical machinery of the parasite from the extracellular environment. Proteins of this type play a key role in antimalarial drug resistance, as well as being candidate drug targets in their own right. This review provides an overview of recent work on the membrane transport biology of the malaria parasite-infected erythrocyte, encompassing both the parasite-induced changes in the membrane transport properties of the host erythrocyte and the cell physiology of the intracellular parasite itself.
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139
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Showler AJ, Wilson ME, Kain KC, Boggild AK. Parasitic diseases in travelers: a focus on therapy. Expert Rev Anti Infect Ther 2014; 12:497-521. [DOI: 10.1586/14787210.2014.892827] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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140
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Gamo FJ. Antimalarial drug resistance: new treatments options for Plasmodium. DRUG DISCOVERY TODAY. TECHNOLOGIES 2014; 11:81-88. [PMID: 24847657 DOI: 10.1016/j.ddtec.2014.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Malaria is one of the world’s most deadly infectious diseases. Millions of lives are threatened by the continued development of resistance in the malaria parasite which is overcoming the effectiveness of current anti- malarial treatments. The scientific community is facing this challenge by developing new and superior therapies to combat, and potentially eradicate, this wide spread plague. New anti-Plasmodium agents derived from phe- notypic screening hits (e.g. spiroindolones) or from target based projects (e.g. DSM265) have recently entered into clinical development and hopefully will provide soon a new wave of antimalarial treatments.
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141
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Krishna S, Pulcini S, Moore CM, Teo BHY, Staines HM. Pumped up: reflections on PfATP6 as the target for artemisinins. Trends Pharmacol Sci 2014; 35:4-11. [DOI: 10.1016/j.tips.2013.10.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 10/11/2013] [Accepted: 10/21/2013] [Indexed: 12/01/2022]
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142
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Spiroindolone that inhibits PfATPase4 is a potent, cidal inhibitor of Toxoplasma gondii tachyzoites in vitro and in vivo. Antimicrob Agents Chemother 2013; 58:1789-92. [PMID: 24366743 DOI: 10.1128/aac.02225-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Here, we show that spiroindolone, an effective treatment for plasmodia, is also active against Toxoplasma gondii tachyzoites. In vitro, spiroindolone NITD609 is cidal for tachyzoites (50% inhibitory concentration [IC50], 1μM) and not toxic to human cells at ≥10μM. Two daily oral doses of 100 mg/kg of body weight reduced the parasite burden in mice by 90% (P=0.002), measured 3 days after the last dose. This inhibition of T. gondii tachyzoites in vitro and in vivo indicates that spiroindolone is a promising lead candidate for further medicine development.
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143
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Antiapicoplast and gametocytocidal screening to identify the mechanisms of action of compounds within the malaria box. Antimicrob Agents Chemother 2013; 58:811-9. [PMID: 24247137 DOI: 10.1128/aac.01500-13] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Malaria remains a significant infectious disease that causes millions of clinical cases and >800,000 deaths per year. The Malaria Box is a collection of 400 commercially available chemical entities that have antimalarial activity. The collection contains 200 drug-like compounds, based on their oral absorption and the presence of known toxicophores, and 200 probe-like compounds, which are intended to represent a broad structural diversity. These compounds have confirmed activities against the asexual intraerythrocytic stages of Plasmodium falciparum and low cytotoxicities, but their mechanisms of action and their activities in other stages of the parasite's life cycle remain to be determined. The apicoplast is considered to be a promising source of malaria-specific targets, and its main function during intraerythrocytic stages is to provide the isoprenoid precursor isopentenyl diphosphate, which can be used for phenotype-based screens to identify compounds targeting this organelle. We screened 400 compounds from the Malaria Box using apicoplast-targeting phenotypic assays to identify their potential mechanisms of action. We identified one compound that specifically targeted the apicoplast. Further analyses indicated that the molecular target of this compound may differ from those of the current antiapicoplast drugs, such as fosmidomycin. Moreover, in our efforts to elucidate the mechanisms of action of compounds from the Malaria Box, we evaluated their activities against other stages of the life cycle of the parasite. Gametocytes are the transmission stage of the malaria parasite and are recognized as a priority target in efforts to eradicate malaria. We identified 12 compounds that were active against gametocytes with 50% inhibitory concentration values of <1 μM.
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144
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Abstract
Malaria elimination has recently been reinstated as a global health priority but current therapies seem to be insufficient for the task. Elimination efforts require new drug classes that alleviate symptoms, prevent transmission and provide a radical cure. To develop these next-generation medicines, public-private partnerships are funding innovative approaches to identify compounds that target multiple parasite species at multiple stages of the parasite life cycle. In this Review, we discuss the cell-, chemistry- and target-based approaches used to discover new drug candidates that are currently in clinical trials or undergoing preclinical testing.
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145
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Abstract
Owing to the absence of antiparasitic vaccines and the constant threat of drug resistance, the development of novel antiparasitic chemotherapies remains of major importance for disease control. A better understanding of drug transport (uptake and efflux), drug metabolism and the identification of drug targets, and mechanisms of drug resistance would facilitate the development of more effective therapies. Here, we focus on malaria and African trypanosomiasis. We review existing drugs and drug development, emphasizing high-throughput genomic and genetic approaches, which hold great promise for elucidating antiparasitic mechanisms. We describe the approaches and technologies that have been influential for each parasite and develop new ideas for future research directions, including mode-of-action studies for drug target deconvolution.
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Affiliation(s)
- David Horn
- Biological Chemistry & Drug Discovery, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Manoj T. Duraisingh
- Harvard School of Public Health, 665 Huntington Avenue, Building 1, Room 715, Boston, Massachusetts 02115, USA
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146
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Flannery EL, Fidock DA, Winzeler EA. Using genetic methods to define the targets of compounds with antimalarial activity. J Med Chem 2013; 56:7761-71. [PMID: 23927658 DOI: 10.1021/jm400325j] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Although phenotypic cellular screening has been used to drive antimalarial drug discovery in recent years, in some cases target-based drug discovery remains more attractive. This is especially true when appropriate high-throughput cellular assays are lacking, as is the case for drug discovery efforts that aim to provide a replacement for primaquine (4-N-(6-methoxyquinolin-8-yl)pentane-1,4-diamine), the only drug that can block Plasmodium transmission to Anopheles mosquitoes and eliminate liver-stage hypnozoites. At present, however, there are no known chemically validated parasite protein targets that are important in all Plasmodium parasite developmental stages and that can be used in traditional biochemical compound screens. We propose that a plethora of novel, chemically validated, cross-stage antimalarial targets still remain to be discovered from the ~5,500 proteins encoded by the Plasmodium genomes. Here we discuss how in vitro evolution of drug-resistant strains of Plasmodium falciparum and subsequent whole-genome analysis can be used to find the targets of some of the many compounds discovered in whole-cell phenotypic screens.
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Affiliation(s)
- Erika L Flannery
- Department of Pediatrics, University of California, San Diego, School of Medicine , 9500 Gilman Drive 0741, La Jolla, California 92093, United States
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147
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Rosenthal PJ. The interplay between drug resistance and fitness in malaria parasites. Mol Microbiol 2013; 89:1025-38. [PMID: 23899091 DOI: 10.1111/mmi.12349] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2013] [Indexed: 12/01/2022]
Abstract
Controlling the spread of antimalarial drug resistance, especially resistance of Plasmodium falciparum to artemisinin-based combination therapies, is a high priority. Available data indicate that, as with other microorganisms, the spread of drug-resistant malaria parasites is limited by fitness costs that frequently accompany resistance. Resistance-mediating polymorphisms in malaria parasites have been identified in putative drug transporters and in target enzymes. The impacts of these polymorphisms on parasite fitness have been characterized in vitro and in animal models. Additional insights have come from analyses of samples from clinical studies, both evaluating parasites under different selective pressures and determining the clinical consequences of infection with different parasites. With some exceptions, resistance-mediating polymorphisms lead to malaria parasites that, compared with wild type, grow less well in culture and in animals, and are replaced by wild type when drug pressure diminishes in the clinical setting. In some cases, the fitness costs of resistance may be offset by compensatory mutations that increase virulence or changes that enhance malaria transmission. However, not enough is known about effects of resistance mediators on parasite fitness. A better appreciation of the costs of fitness-mediating mutations will facilitate the development of optimal guidelines for the treatment and prevention of malaria.
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Affiliation(s)
- Philip J Rosenthal
- Department of Medicine, University of California, San Francisco, CA, 94143, USA
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148
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Progressing the global antimalarial portfolio: finding drugs which target multiple Plasmodium life stages. Parasitology 2013; 141:66-76. [PMID: 23746048 DOI: 10.1017/s0031182013000747] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The number of novel antimalarial candidates entering preclinical development has seen an increase over the last several years. Most of these drug candidates were originally identified as hits coming from screening large chemical libraries specifically targeting the asexual blood stages of Plasmodium falciparum. Indeed, a large proportion of the current antimalarial arsenal has mainly targeted the asexual blood stage which is responsible for clinical symptoms of the disease. However, as part of the eradication agenda and to address resistance, any next-generation antimalarial should have additional activity on at least one other parasite life stage, i.e. gametocytocidal and/or tissue schizonticidal activity. We have applied this approach by screening compounds with intrinsic activity on asexual blood stages in assays against sexual and liver stages and identified two new antimalarial chemotypes with activity on multiple parasite life stages. This strategy can be expanded to identify other chemical classes of molecules with similar activity profiles for the next generation antimalarials. The following review summarizes the discovery of the spiroindolones and imidazolopiperazine classes of antimalarials developed by the NGBS consortium (Novartis Institute for Tropical Diseases, Genomic Institute of the Novartis Research Foundation, Biomedical Primate Research Center, and the Swiss Tropical and Public Health Institute) currently in clinical trials.
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149
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Spillman NJ, Allen RJ, Kirk K. Na+ extrusion imposes an acid load on the intraerythrocytic malaria parasite. Mol Biochem Parasitol 2013; 189:1-4. [DOI: 10.1016/j.molbiopara.2013.04.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 04/11/2013] [Accepted: 04/15/2013] [Indexed: 01/02/2023]
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