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Singh S, Rajendran V, He J, Singh AK, Achieng AO, Vandana, Pant A, Nasamu AS, Pandit M, Singh J, Quadiri A, Gupta N, Poonam, Ghosh PC, Singh BK, Narayanan L, Kempaiah P, Chandra R, Dunn BM, Pandey KC, Goldberg DE, Singh AP, Rathi B. Fast-Acting Small Molecules Targeting Malarial Aspartyl Proteases, Plasmepsins, Inhibit Malaria Infection at Multiple Life Stages. ACS Infect Dis 2019; 5:184-198. [PMID: 30554511 DOI: 10.1021/acsinfecdis.8b00197] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The eradication of malaria remains challenging due to the complex life cycle of Plasmodium and the rapid emergence of drug-resistant forms of Plasmodium falciparum and Plasmodium vivax. New, effective, and inexpensive antimalarials against multiple life stages of the parasite are urgently needed to combat the spread of malaria. Here, we synthesized a set of novel hydroxyethylamines and investigated their activities in vitro and in vivo. All of the compounds tested had an inhibitory effect on the blood stage of P. falciparum at submicromolar concentrations, with the best showing 50% inhibitory concentrations (IC50) of around 500 nM against drug-resistant P. falciparum parasites. These compounds showed inhibitory actions against plasmepsins, a family of malarial aspartyl proteases, and exhibited a marked killing effect on blood stage Plasmodium. In chloroquine-resistant Plasmodium berghei and P. berghei ANKA infected mouse models, treating mice with both compounds led to a significant decrease in blood parasite load. Importantly, two of the compounds displayed an inhibitory effect on the gametocyte stages (III-V) of P. falciparum in culture and the liver-stage infection of P. berghei both in in vitro and in vivo. Altogether, our findings suggest that fast-acting hydroxyethylamine-phthalimide analogs targeting multiple life stages of the parasite could be a valuable chemical lead for the development of novel antimalarial drugs.
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Affiliation(s)
- Snigdha Singh
- Laboratory for Translational Chemistry and Drug Discovery, Department of Chemistry, Hansraj College University Enclave, University of Delhi, Delhi 110007, India
- Department of Chemistry, University of Delhi, Delhi 110007, India
| | - Vinoth Rajendran
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | - Jiang He
- Institute for Medical Engineering and Science, Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Amit K. Singh
- Department of Chemistry, University of Delhi, Delhi 110007, India
| | - Angela O. Achieng
- Center for Global Health, Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, United States
| | - Vandana
- Host−Parasite Interaction Biology Group, National Institute of Malaria Research, Lab. No. 219, Sector-8 Dwarka, New Delhi 110077, India
| | - Akansha Pant
- Host−Parasite Interaction Biology Group, National Institute of Malaria Research, Lab. No. 219, Sector-8 Dwarka, New Delhi 110077, India
| | - Armiyaw S. Nasamu
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri 63110, United States
| | - Mansi Pandit
- Bioinformatics Infrastructure Facility, Sri Venkateswara College, University of Delhi South Campus, New Delhi 110021, India
| | - Jyoti Singh
- Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Afshana Quadiri
- Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Nikesh Gupta
- Special Centre for Nanosciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Poonam
- Department of Chemistry, Miranda House, University of Delhi North Campus, Delhi 110007, India
| | - Prahlad C. Ghosh
- Department of Biochemistry, University of Delhi South Campus, New Delhi 110021, India
| | | | - Latha Narayanan
- Bioinformatics Infrastructure Facility, Sri Venkateswara College, University of Delhi South Campus, New Delhi 110021, India
| | - Prakasha Kempaiah
- Center for Global Health, Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, United States
- Department of Medicine, Loyola University Stritch School of Medicine, 2160 South First Avenue, Chicago, Illinois 60153, United States
| | - Ramesh Chandra
- Department of Chemistry, University of Delhi, Delhi 110007, India
| | - Ben M. Dunn
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, P.O. Box 100245, Gainesville, Florida 32610, United States
| | - Kailash C. Pandey
- Host−Parasite Interaction Biology Group, National Institute of Malaria Research, Lab. No. 219, Sector-8 Dwarka, New Delhi 110077, India
- Department of Biochemistry, National Institute for Research in Environmental Health, ICMR, Bhopal 462001, India
| | - Daniel E. Goldberg
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri 63110, United States
| | - Agam P. Singh
- Infectious Diseases Laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Brijesh Rathi
- Laboratory for Translational Chemistry and Drug Discovery, Department of Chemistry, Hansraj College University Enclave, University of Delhi, Delhi 110007, India
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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Recacha R, Leitans J, Akopjana I, Aprupe L, Trapencieris P, Jaudzems K, Jirgensons A, Tars K. Structures of plasmepsin II from Plasmodium falciparum in complex with two hydroxyethylamine-based inhibitors. Acta Crystallogr F Struct Biol Commun 2015; 71:1531-9. [PMID: 26625296 PMCID: PMC4666482 DOI: 10.1107/s2053230x15022049] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 11/18/2015] [Indexed: 11/10/2022] Open
Abstract
Plasmepsin II (PMII) is one of the ten plasmepsins (PMs) identified in the genome of Plasmodium falciparum, the causative agent of the most severe and deadliest form of malaria. Owing to the emergence of P. falciparum strains that are resistant to current antimalarial agents such as chloroquine and sulfadoxine/pyrimethamine, there is a constant pressure to find new and lasting chemotherapeutic drug therapies. Previously, the crystal structure of PMII in complex with NU655, a potent antimalarial hydroxyethylamine-based inhibitor, and the design of new compounds based on it have been reported. In the current study, two of these newly designed hydroxyethylamine-based inhibitors, PG418 and PG394, were cocrystallized with PMII and their structures were solved, analyzed and compared with that of the PMII-NU655 complex. Structural analysis of the PMII-PG418 complex revealed that the flap loop can adopt a fully closed conformation, stabilized by interactions with the inhibitor, and a fully open conformation, causing an overall expansion in the active-site cavity, which in turn causes unstable binding of the inhibitor. PG418 also stabilizes the flexible loop Gln275-Met286 of another monomer in the asymmetric unit of PMII, which is disordered in the PMII-NU655 complex structure. The crystal structure of PMII in complex with the inhibitor PG418 demonstrates the conformational flexibility of the active-site cavity of the plasmepsins. The interactions of the different moieties in the P1' position of PG418 and PG394 with Thr217 have to be taken into account in the design of new potent plasmepsin inhibitors.
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Affiliation(s)
- Rosario Recacha
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga, LV-1006, Latvia
| | - Janis Leitans
- Biomedical Research and Study Centre, Ratsupites 1, Riga, LV-1067, Latvia
| | - Inara Akopjana
- Biomedical Research and Study Centre, Ratsupites 1, Riga, LV-1067, Latvia
| | - Lilija Aprupe
- Biomedical Research and Study Centre, Ratsupites 1, Riga, LV-1067, Latvia
| | | | - Kristaps Jaudzems
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga, LV-1006, Latvia
| | - Aigars Jirgensons
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga, LV-1006, Latvia
| | - Kaspars Tars
- Biomedical Research and Study Centre, Ratsupites 1, Riga, LV-1067, Latvia
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Jaudzems K, Tars K, Maurops G, Ivdra N, Otikovs M, Leitans J, Kanepe-Lapsa I, Domraceva I, Mutule I, Trapencieris P, Blackman MJ, Jirgensons A. Plasmepsin inhibitory activity and structure-guided optimization of a potent hydroxyethylamine-based antimalarial hit. ACS Med Chem Lett 2014; 5:373-7. [PMID: 24900843 DOI: 10.1021/ml4004952] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 01/13/2014] [Indexed: 11/29/2022] Open
Abstract
Antimalarial hit 1 SR (TCMDC-134674) identified in a GlaxoSmithKline cell based screening campaign was evaluated for inhibitory activity against the digestive vacuole plasmepsins (Plm I, II, and IV). It was found to be a potent Plm IV inhibitor with no selectivity over Cathepsin D. A cocrystal structure of 1 SR bound to Plm II was solved, providing structural insight for the design of more potent and selective analogues. Structure-guided optimization led to the identification of structurally simplified analogues 17 and 18 as low nanomolar inhibitors of both, plasmepsin Plm IV activity and P. falciparum growth in erythrocytes.
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Affiliation(s)
- Kristaps Jaudzems
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga LV-1006, Latvia
| | - Kaspars Tars
- Biomedical Research and Study Centre, Ratsupites 1, Riga LV-1067, Latvia
| | - Gundars Maurops
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga LV-1006, Latvia
| | - Natalija Ivdra
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga LV-1006, Latvia
| | - Martins Otikovs
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga LV-1006, Latvia
| | - Janis Leitans
- Biomedical Research and Study Centre, Ratsupites 1, Riga LV-1067, Latvia
| | - Iveta Kanepe-Lapsa
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga LV-1006, Latvia
| | - Ilona Domraceva
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga LV-1006, Latvia
| | - Ilze Mutule
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga LV-1006, Latvia
| | | | - Michael J. Blackman
- Division
of Parasitology, MRC National Institute for Medical Research, The Ridgeway, Mill, Hill, London NW7 1AA, U.K
| | - Aigars Jirgensons
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga LV-1006, Latvia
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