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Olanlokun JO, Owolabi AB, Odedeyi A, Oderinde SO, Bodede O, Steenkamp P, Koorbanally NA, Olorunsogo OO. Mechanism of antimalarial action and mitigation of infection-mediated mitochondrial dysfunction by phyto-constituents of Andrographis paniculata ((Burm f.) Wall. ex Nees) in Plasmodium berghei-infected mice. JOURNAL OF ETHNOPHARMACOLOGY 2024; 331:118241. [PMID: 38670400 DOI: 10.1016/j.jep.2024.118241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 04/17/2024] [Accepted: 04/22/2024] [Indexed: 04/28/2024]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Andrographis paniculata (AP) ((Burm f.) Wall. ex Nees) is a medicinal plant, documented for its folkloric use in the treatment of malaria. AIM This study was designed to determine the potency of extract and fractions of A. paniculata (AP) as a curative, both for susceptible and resistant malaria and to also determine the plant's mechanism of action. This study was also designed to determine whether AP extract and its most potent fraction will mitigate infection-mediated mitochondrial dysfunction, and to assess the phytochemical constituents of the most potent fraction. MATERIALS AND METHODS n-Hexane, dichloromethane, ethylacetate and methanol were used to partition the methanol extract of A. paniculata. Graded doses of these extract and fractions were used to treat mice infected with chloroquine-sensitive strain of P. berghei in a curative model. The most potent fraction was used to treat mice infected with resistant (ANKA strain) P. berghei. Inhibition of hemozoin formation, reversal of mitochondrial dysfunction and antiinflammatory potentials were determined. A combination of ultraperformance liquid chromatography-quadrupole time of flight-mass spectrometry and nuclear magnetic resonance spectroscopy were used for chemical analysis. RESULTS Microscopy revealed that the dichloromethane fraction decreased the parasite burden the most, and inhibition of the hemozoin formation is one of its mechanisms of action. The dichloromethane fraction reversed parasite-induced mitochondrial pore opening in the host, enzyme-dependent ATP hydrolysis and peroxidation of host mitochondrial membrane phospholipids as well as its antiinflammatory potentials. The UPLC-qTOF-MS report and NMR fingerprints of the dichloromethane fraction of A. paniculata yielded fourteen compounds of which sibiricinone C was identified from the plant for the first time. CONCLUSION Fractions of A. paniculata possess antiplasmodial effects with the dichloromethane fraction having the highest potency. The potent effect of this fraction may be attributed to the phytochemicals present because it contains terpenes implicated with antimalarial and antiinflammatory activities.
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Affiliation(s)
- John Oludele Olanlokun
- Laboratories for Biomembrane Research and Biotechnology, Department of Biochemistry, University of Ibadan, Ibadan, Nigeria.
| | - Adesola Bunmi Owolabi
- Laboratories for Biomembrane Research and Biotechnology, Department of Biochemistry, University of Ibadan, Ibadan, Nigeria
| | - Aminat Odedeyi
- Laboratories for Biomembrane Research and Biotechnology, Department of Biochemistry, University of Ibadan, Ibadan, Nigeria
| | - Solomon Obaloluwa Oderinde
- Laboratories for Biomembrane Research and Biotechnology, Department of Biochemistry, University of Ibadan, Ibadan, Nigeria
| | - Olusola Bodede
- Department of Chemistry, University of Pretoria, Pretoria, 0028, South Africa
| | - Paul Steenkamp
- Centre for Plant Metabolomics, Department of Biochemistry, University of Johannesburg, P.O. Box 524, Auckland Park, 2006, South Africa
| | | | - Olufunso Olabode Olorunsogo
- Laboratories for Biomembrane Research and Biotechnology, Department of Biochemistry, University of Ibadan, Ibadan, Nigeria
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Mahanta PJ, Lhouvum K. Plasmodium falciparum proteases as new drug targets with special focus on metalloproteases. Mol Biochem Parasitol 2024; 258:111617. [PMID: 38554736 DOI: 10.1016/j.molbiopara.2024.111617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 02/15/2024] [Accepted: 03/10/2024] [Indexed: 04/02/2024]
Abstract
Malaria poses a significant global health threat particularly due to the prevalence of Plasmodium falciparum infection. With the emergence of parasite resistance to existing drugs including the recently discovered artemisinin, ongoing research seeks novel therapeutic avenues within the malaria parasite. Proteases are promising drug targets due to their essential roles in parasite biology, including hemoglobin digestion, merozoite invasion, and egress. While exploring the genomic landscape of Plasmodium falciparum, it has been revealed that there are 92 predicted proteases, with only approximately 14 of them having been characterized. These proteases are further distributed among 26 families grouped into five clans: aspartic proteases, cysteine proteases, metalloproteases, serine proteases, and threonine proteases. Focus on metalloprotease class shows further role in organelle processing for mitochondria and apicoplasts suggesting the potential of metalloproteases as viable drug targets. Holistic understanding of the parasite intricate life cycle and identification of potential drug targets are essential for developing effective therapeutic strategies against malaria and mitigating its devastating global impact.
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Affiliation(s)
| | - Kimjolly Lhouvum
- Department of Biotechnology, National Institute of Technology, Arunachal Pradesh, India.
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Charles S, Mahapatra RK. Artificial intelligence based de-novo design for novel Plasmodium falciparum plasmepsin (PM) X inhibitors. J Biomol Struct Dyn 2023:1-16. [PMID: 37943000 DOI: 10.1080/07391102.2023.2279700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 10/27/2023] [Indexed: 11/10/2023]
Abstract
Plasmodium falciparum is the leading cause of malaria with 627,000 deaths annually. Invasion and egress are critical stages for successful infection of the host yet depend on proteins that are extensively pre-processed by various maturases. Plasmepsins (Plasmodium pepsins, abbreviated PM, I-X) are pepsin-like aspartic proteases that are involved in almost all stages of the life cycle. The goal of this study was to use de-novo generative modeling techniques to create novel potential PfPMX inhibitors. A total of 4325 compounds were virtually screened by structural-based docking methods. The obtained hits were utilized to refine a structure-based Ligand Neural Network (L-Net) generative model to generate related compounds. The obtained optimal L-Net Compounds with smina scores ≤ -5.00KCalmol-1 and QED ≥ 0.35 were further taken for amplification utilizing Ligand Based Transformer modeling using Deep generative learning (Drug Explorer/DrugEx). The resulting hits were then subjected to XP Glide conventional Molecular docking and QikProp ADMET screening; molecules with XP Docking score ≤ -7.00KCalmol-1 were retained. Based on their Glide ligand efficiency, originality, and uniqueness, 30 compounds were chosen for binding affinity and MM_GBSA energy determination. Following Induced Fit docking (IFD), 7 compounds were taken for 50 ns MD simulations and FEP/MD calculations. This study reported novel potential PfPMX inhibitors with acceptable ADMET profiles and reasonable synthetic accessibility scores, as well as sufficient docking scores against other PMs were generated. The PfPMX inhibitors reported in this article are promising antimalarials for the next stages of drug development, and the first of their kind to be investigated thoroughly.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Ssemuyiga Charles
- School of Biotechnology, KIIT Deemed to be University, Bhubaneswar, Odisha, India
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Abdulai SI, Ishola AA, Bewaji CO. Antimalarial Activities of a Therapeutic Combination of Azadirachta indica, Mangifera indica and Morinda lucida Leaves: A Molecular View of its Activity on Plasmodium falciparum Proteins. Acta Parasitol 2023; 68:659-675. [PMID: 37474844 DOI: 10.1007/s11686-023-00698-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 06/26/2023] [Indexed: 07/22/2023]
Abstract
BACKGROUND The search for new antimalarial drugs remains elusive prompting research into antimalarial combinations from medicinal plants due to their cheapness, efficacy and availability. Azadirachta indica (AI), Morinda lucida (ML) and Mangifera indica (MI) have all been reported as potent antimalarial plants. PURPOSE This study evaluated the efficacy of an antimalarial combination therapeutics prepared from leaves of AI, ML and MI using in vitro, in vivo and molecular methods. METHODS Refined extracts of the plants combination was made by partitioning the aqueous extract of plants combinations (AI + MI, AI + ML, MI + ML, AI + MI + ML) using methanol and ethyl acetate consecutively. The resulting ethyl acetate partitioned fraction was evaluated for its antimalarial activity. Molecular docking and molecular dynamics simulation were employed to determine the possible mechanism of action of the constituent of the most active combination against four important P. falciparum proteins. RESULTS The result revealed that the refined extract from combinations AI + ML and MI + ML at 16 mg/kg bodyweight have the highest chemo-suppressive effect of 90.7% and 91.0% respectively compared to chloroquine's 100% at 10 mg/kg. Also, refined extract from MI + ML combination improved PCV levels significantly (p < 0.05) compared to controls. Molecular docking revealed oleanolic acid and ursolic acid as multiple inhibitors of plasmepsin II, hiso-aspartic protease, falcipain-2 and P. falciparum Eonyl acyl-carrier protein reductase with relative stability during 100 ns of simulation. CONCLUSION The study unveiled the potentials of ML and MI as good candidates for antimalarial combination therapy and further established their use together as revealed in folklore medicine.
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Affiliation(s)
- Suliat Iyabode Abdulai
- Department of Chemical Sciences, Biochemistry and Nutrition Unit, Fountain University, Osogbo, Osun State, Nigeria.
| | - Ahmed Adebayo Ishola
- Central Research Lab, 132B, University Road, Tanke, Ilorin, Nigeria.
- Department of Biochemistry, University of Ilorin, Ilorin, Nigeria.
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5
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Ong JJY, Oh J, Yong Ang X, Naidu R, Chu TTT, Hyoung Im J, Manzoor U, Kha Nguyen T, Na SW, Han ET, Davis C, Sun Park W, Chun W, Jun H, Jin Lee S, Na S, Chan JKY, Park Y, Russell B, Chandramohanadas R, Han JH. Optical diffraction tomography and image reconstruction to measure host cell alterations caused by divergent Plasmodium species. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 286:122026. [PMID: 36395614 DOI: 10.1016/j.saa.2022.122026] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 09/29/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
Malaria is a life-threatening infectious disease caused by parasites of the genus Plasmodium. Understanding the biological features of various parasite forms is important for the optical diagnosis and defining pathological states, which are often constrained by the lack of ambient visualization approaches. Here, we employ a label-free tomographic technique to visualize the host red blood cell (RBC) remodeling process and quantify changes in biochemical properties arising from parasitization. Through this, we provide a quantitative body of information pertaining to the influence of host cell environment on growth, survival, and replication of P. falciparum and P. vivax in their respective host cells: mature erythrocytes and young reticulocytes. These exquisite three-dimensional measurements of infected red cells demonstrats the potential of evolving 3D imaging to advance our understanding of Plasmodium biology and host-parasite interactions.
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Affiliation(s)
- Jessica J Y Ong
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Jeonghun Oh
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea; KAIST Institute for Health Science and Technology, KAIST, Daejeon 34141, Republic of Korea
| | - Xiang Yong Ang
- Department of Microbiology and Immunology, National University of Singapore, Singapore
| | - Renugah Naidu
- Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore, Singapore
| | - Trang T T Chu
- Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore, Singapore
| | - Jae Hyoung Im
- Department of Infectious Disease, Inha University School of Medicine, Incheon 22212, Republic of Korea
| | - Umar Manzoor
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Tuyet Kha Nguyen
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Seok-Won Na
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Christeen Davis
- DBT Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India; Manipal Academy of Higher Education, Manipal, Karnataka 576104, India
| | - Won Sun Park
- Department of Physiology, School of Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Wanjoo Chun
- Department of Pharmacology, School of Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Hojong Jun
- Department of Tropical Medicine, Inha University College of Medicine, Incheon 22212, Republic of Korea
| | - Se Jin Lee
- Department of Obstetrics and Gynecology, Kangwon National University Hospital, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Sunghun Na
- Department of Obstetrics and Gynecology, Kangwon National University Hospital, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Jerry K Y Chan
- KK Womens' and Childrens' Hospital, Singapore; Academic Clinical Program in Obstetrics and Gynaecology, Duke-NUS Medical School, 169857, Singapore
| | - YongKeun Park
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea; KAIST Institute for Health Science and Technology, KAIST, Daejeon 34141, Republic of Korea; Tomocube Inc, Daejeon 34109, Republic of Korea
| | - Bruce Russell
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Rajesh Chandramohanadas
- Department of Microbiology and Immunology, National University of Singapore, Singapore; Pillar of Engineering Product Development, Singapore University of Technology and Design, Singapore, Singapore; DBT Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, Kerala, India.
| | - Jin-Hee Han
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand; Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon 24341, Republic of Korea.
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6
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Aguado ME, Izquierdo M, González-Matos M, Varela AC, Méndez Y, Del Rivero MA, Rivera DG, González-Bacerio J. Parasite Metalo-aminopeptidases as Targets in Human Infectious Diseases. Curr Drug Targets 2023; 24:416-461. [PMID: 36825701 DOI: 10.2174/1389450124666230224140724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 12/25/2022] [Accepted: 01/02/2023] [Indexed: 02/25/2023]
Abstract
BACKGROUND Parasitic human infectious diseases are a worldwide health problem due to the increased resistance to conventional drugs. For this reason, the identification of novel molecular targets and the discovery of new chemotherapeutic agents are urgently required. Metalo- aminopeptidases are promising targets in parasitic infections. They participate in crucial processes for parasite growth and pathogenesis. OBJECTIVE In this review, we describe the structural, functional and kinetic properties, and inhibitors, of several parasite metalo-aminopeptidases, for their use as targets in parasitic diseases. CONCLUSION Plasmodium falciparum M1 and M17 aminopeptidases are essential enzymes for parasite development, and M18 aminopeptidase could be involved in hemoglobin digestion and erythrocyte invasion and egression. Trypanosoma cruzi, T. brucei and Leishmania major acidic M17 aminopeptidases can play a nutritional role. T. brucei basic M17 aminopeptidase down-regulation delays the cytokinesis. The inhibition of Leishmania basic M17 aminopeptidase could affect parasite viability. L. donovani methionyl aminopeptidase inhibition prevents apoptosis but not the parasite death. Decrease in Acanthamoeba castellanii M17 aminopeptidase activity produces cell wall structural modifications and encystation inhibition. Inhibition of Babesia bovis growth is probably related to the inhibition of the parasite M17 aminopeptidase, probably involved in host hemoglobin degradation. Schistosoma mansoni M17 aminopeptidases inhibition may affect parasite development, since they could participate in hemoglobin degradation, surface membrane remodeling and eggs hatching. Toxoplasma gondii M17 aminopeptidase inhibition could attenuate parasite virulence, since it is apparently involved in the hydrolysis of cathepsin Cs- or proteasome-produced dipeptides and/or cell attachment/invasion processes. These data are relevant to validate these enzymes as targets.
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Affiliation(s)
- Mirtha E Aguado
- Center for Protein Studies, Faculty of Biology, University of Havana, Calle 25 #455 Entre I y J, 10400, Vedado, La Habana, Cuba
| | - Maikel Izquierdo
- Center for Protein Studies, Faculty of Biology, University of Havana, Calle 25 #455 Entre I y J, 10400, Vedado, La Habana, Cuba
| | - Maikel González-Matos
- Center for Protein Studies, Faculty of Biology, University of Havana, Calle 25 #455 Entre I y J, 10400, Vedado, La Habana, Cuba
| | - Ana C Varela
- Center for Protein Studies, Faculty of Biology, University of Havana, Calle 25 #455 Entre I y J, 10400, Vedado, La Habana, Cuba
| | - Yanira Méndez
- Center for Natural Products Research, Faculty of Chemistry, University of Havana, Zapata y G, 10400, La Habana, Cuba
| | - Maday A Del Rivero
- Center for Protein Studies, Faculty of Biology, University of Havana, Calle 25 #455 Entre I y J, 10400, Vedado, La Habana, Cuba
| | - Daniel G Rivera
- Center for Natural Products Research, Faculty of Chemistry, University of Havana, Zapata y G, 10400, La Habana, Cuba
| | - Jorge González-Bacerio
- Center for Protein Studies, Faculty of Biology, University of Havana, Calle 25 #455 Entre I y J, 10400, Vedado, La Habana, Cuba
- Department of Biochemistry, Faculty of Biology, University of Havana, calle 25 #455 entre I y J, 10400, Vedado, La Habana, Cuba
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Matz JM. Plasmodium’s bottomless pit: properties and functions of the malaria parasite's digestive vacuole. Trends Parasitol 2022; 38:525-543. [DOI: 10.1016/j.pt.2022.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 02/21/2022] [Accepted: 02/21/2022] [Indexed: 11/30/2022]
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A Phosphoinositide-Binding Protein Acts in the Trafficking Pathway of Hemoglobin in the Malaria Parasite Plasmodium falciparum. mBio 2022; 13:e0323921. [PMID: 35038916 PMCID: PMC8764524 DOI: 10.1128/mbio.03239-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Phosphoinositide lipids play key roles in a variety of processes in eukaryotic cells, but our understanding of their functions in the malaria parasite Plasmodium falciparum is still very much limited. To gain a deeper comprehension of the roles of phosphoinositides in this important pathogen, we attempted gene inactivation for 24 putative effectors of phosphoinositide metabolism. Our results reveal that 79% of the candidates are refractory to genetic deletion and are therefore potentially essential for parasite growth. Inactivation of the gene coding for a Plasmodium-specific putative phosphoinositide-binding protein, which we named PfPX1, results in a severe growth defect. We show that PfPX1 likely binds phosphatidylinositol-3-phosphate and that it localizes to the membrane of the digestive vacuole of the parasite and to vesicles filled with host cell cytosol and labeled with endocytic markers. Critically, we provide evidence that it is important in the trafficking pathway of hemoglobin from the host erythrocyte to the digestive vacuole. Finally, inactivation of PfPX1 renders parasites resistant to artemisinin, the frontline antimalarial drug. Globally, the minimal redundancy in the putative phosphoinositide proteins uncovered in our work supports that targeting this pathway has potential for antimalarial drug development. Moreover, our identification of a phosphoinositide-binding protein critical for the trafficking of hemoglobin provides key insight into this essential process. IMPORTANCE Malaria represents an enormous burden for a significant proportion of humanity, and the lack of vaccines and problems with drug resistance to all antimalarials demonstrate the need to develop new therapeutics. Inhibitors of phosphoinositide metabolism are currently being developed as antimalarials but our understanding of this biological pathway is incomplete. The malaria parasite lives inside human red blood cells where it imports hemoglobin to cover some of its nutritional needs. In this work, we have identified a phosphoinositide-binding protein that is important for the transport of hemoglobin in the parasite. Inactivation of this protein decreases the ability of the parasite to proliferate. Our results have therefore identified a potential new target for antimalarial development.
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Kamat S, Kumari M. Repurposing Chloroquine Against Multiple Diseases With Special Attention to SARS-CoV-2 and Associated Toxicity. Front Pharmacol 2021; 12:576093. [PMID: 33912030 PMCID: PMC8072386 DOI: 10.3389/fphar.2021.576093] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 02/08/2021] [Indexed: 12/13/2022] Open
Abstract
Chloroquine and its derivatives have been used since ages to treat malaria and have also been approved by the FDA to treat autoimmune diseases. The drug employs pH-dependent inhibition of functioning and signalling of the endosome, lysosome and trans-Golgi network, immunomodulatory actions, inhibition of autophagy and interference with receptor binding to treat cancer and many viral diseases. The ongoing pandemic of COVID-19 has brought the whole world on the knees, seeking an urgent hunt for an anti-SARS-CoV-2 drug. Chloroquine has shown to inhibit receptor binding of the viral particles, interferes with their replication and inhibits "cytokine storm". Though multiple modes of actions have been employed by chloroquine against multiple diseases, viral diseases can provide an added advantage to establish the anti-SARS-CoV-2 mechanism, the in vitro and in vivo trials against SARS-CoV-2 have yielded mixed results. The toxicological effects and dosage optimization of chloroquine have been studied for many diseases, though it needs a proper evaluation again as chloroquine is also associated with several toxicities. Moreover, the drug is inexpensive and is readily available in many countries. Though much of the hope has been created by chloroquine and its derivatives against multiple diseases, repurposing it against SARS-CoV-2 requires large scale, collaborative, randomized and unbiased clinical trials to avoid false promises. This review summarizes the use and the mechanism of chloroquine against multiple diseases, its side-effects, mechanisms and the different clinical trials ongoing against "COVID-19".
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Affiliation(s)
| | - Madhuree Kumari
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
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10
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Shafik SH, Cobbold SA, Barkat K, Richards SN, Lancaster NS, Llinás M, Hogg SJ, Summers RL, McConville MJ, Martin RE. The natural function of the malaria parasite's chloroquine resistance transporter. Nat Commun 2020; 11:3922. [PMID: 32764664 PMCID: PMC7413254 DOI: 10.1038/s41467-020-17781-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 07/15/2020] [Indexed: 01/27/2023] Open
Abstract
The Plasmodium falciparum chloroquine resistance transporter (PfCRT) is a key contributor to multidrug resistance and is also essential for the survival of the malaria parasite, yet its natural function remains unresolved. We identify host-derived peptides of 4-11 residues, varying in both charge and composition, as the substrates of PfCRT in vitro and in situ, and show that PfCRT does not mediate the non-specific transport of other metabolites and/or ions. We find that drug-resistance-conferring mutations reduce both the peptide transport capacity and substrate range of PfCRT, explaining the impaired fitness of drug-resistant parasites. Our results indicate that PfCRT transports peptides from the lumen of the parasite's digestive vacuole to the cytosol, thereby providing a source of amino acids for parasite metabolism and preventing osmotic stress of this organelle. The resolution of PfCRT's native substrates will aid the development of drugs that target PfCRT and/or restore the efficacy of existing antimalarials.
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Affiliation(s)
- Sarah H Shafik
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Simon A Cobbold
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC, 3052, Australia
| | - Kawthar Barkat
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Sashika N Richards
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Nicole S Lancaster
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Manuel Llinás
- Department of Biochemistry and Molecular Biology, Department of Chemistry, and Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Simon J Hogg
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Robert L Summers
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Malcolm J McConville
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC, 3052, Australia
| | - Rowena E Martin
- Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia.
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Nasamu AS, Polino AJ, Istvan ES, Goldberg DE. Malaria parasite plasmepsins: More than just plain old degradative pepsins. J Biol Chem 2020; 295:8425-8441. [PMID: 32366462 PMCID: PMC7307202 DOI: 10.1074/jbc.rev120.009309] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Plasmepsins are a group of diverse aspartic proteases in the malaria parasite Plasmodium Their functions are strikingly multifaceted, ranging from hemoglobin degradation to secretory organelle protein processing for egress, invasion, and effector export. Some, particularly the digestive vacuole plasmepsins, have been extensively characterized, whereas others, such as the transmission-stage plasmepsins, are minimally understood. Some (e.g. plasmepsin V) have exquisite cleavage sequence specificity; others are fairly promiscuous. Some have canonical pepsin-like aspartic protease features, whereas others have unusual attributes, including the nepenthesin loop of plasmepsin V and a histidine in place of a catalytic aspartate in plasmepsin III. We have learned much about the functioning of these enzymes, but more remains to be discovered about their cellular roles and even their mechanisms of action. Their importance in many key aspects of parasite biology makes them intriguing targets for antimalarial chemotherapy. Further consideration of their characteristics suggests that some are more viable drug targets than others. Indeed, inhibitors of invasion and egress offer hope for a desperately needed new drug to combat this nefarious organism.
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Affiliation(s)
- Armiyaw S Nasamu
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Alexander J Polino
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Eva S Istvan
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Daniel E Goldberg
- Division of Infectious Diseases, Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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12
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Proteomic analysis of Plasmodium falciparum response to isocryptolepine derivative. PLoS One 2019; 14:e0220871. [PMID: 31393938 PMCID: PMC6687117 DOI: 10.1371/journal.pone.0220871] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Accepted: 07/24/2019] [Indexed: 11/19/2022] Open
Abstract
Drug-resistant strains of malaria parasites have emerged for most of antimalarial medications. A new chemotherapeutic compound is needed for malarial therapy. Antimalarial activity against both drug-sensitive and drug-resistant P. falciparum has been reported for an isocryptolepine derivative, 8-bromo-2-fluoro-5-methyl-5H-indolo[3,2-c]quinoline (ICL-M), which also showed less toxicity to human cells. ICL-M has indoloquinoline as a core structure and its mode of action remains unclear. Here, we explored the mechanisms of ICL-M in P. falciparum by assessing the stage-specific activity, time-dependent effect, a proteomic analysis and morphology. Since human topo II activity inhibition has been reported as a function of isocryptolepine derivatives, malarial topo II activity inhibition of ICL-M was also examined in this study. The ICL-M exhibited antimalarial activity against both the ring and trophozoite stages of P. falciparum. Our proteomics analysis revealed that a total of 112 P. falciparum proteins were differentially expressed after ICL-M exposure; among these, 58 and 54 proteins were upregulated and downregulated, respectively. Proteins localized in the food vacuole, nucleus, and cytoplasm showed quantitative alterations after ICL-M treatment. A bioinformatic analysis revealed that pathways associated with ribosomes, proteasomes, metabolic pathways, amino acid biosynthesis, oxidative phosphorylation, and carbon metabolism were significantly different in P. falciparum treated with ICL-M. Moreover, a loss of ribosomes was clearly observed by transmission electron microscopy in the ICL-M-treated P. falciparum. This finding is in agreement with the proteomics data, which revealed downregulated levels of ribosomal proteins following ICL-M treatment. Our results provide important information about the mechanisms by which ICL-M affects the malaria parasite, which may facilitate the drug development of isocryptolepine derivatives.
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Xue Q. Pathogen proteases and host protease inhibitors in molluscan infectious diseases. J Invertebr Pathol 2019; 166:107214. [PMID: 31348922 DOI: 10.1016/j.jip.2019.107214] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 04/11/2019] [Accepted: 06/28/2019] [Indexed: 12/17/2022]
Abstract
The development of infectious diseases represents an outcome of dynamic interactions between the disease-producing agent's pathogenicity and the host's self-defense mechanism. Proteases secreted by pathogenic microorganisms and protease inhibitors produced by host species play an important role in the process. This review aimed at summarizing major findings in research on pathogen proteases and host protease inhibitors that had been proposed to be related to the development of mollusk diseases. Metalloproteases and serine proteases respectively belonging to Family M4 and Family S8 of the MEROPS system are among the most studied proteases that may function as virulence factors in mollusk pathogens. On the other hand, a mollusk-specific family (Family I84) of novel serine protease inhibitors and homologues of the tissue inhibitor of metalloprotease have been studied for their potential in the molluscan host defense. In addition, research at the genomic and transcriptomic levels showed that more proteases of pathogens and protease inhibitor of hosts are likely involved in mollusk disease processes. Therefore, the pathological significance of interactions between pathogen proteases and host protease inhibitors in the development of molluscan infectious diseases deserves more research efforts.
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Affiliation(s)
- Qinggang Xue
- Zhejiang Key Lab of Aquatic Germplasm Resources, Zhejiang Wanli University, Ningbo, Zhejiang 315100, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China.
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14
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Heller LE, Roepe PD. Artemisinin-Based Antimalarial Drug Therapy: Molecular Pharmacology and Evolving Resistance. Trop Med Infect Dis 2019; 4:tropicalmed4020089. [PMID: 31167396 PMCID: PMC6631165 DOI: 10.3390/tropicalmed4020089] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 05/21/2019] [Accepted: 05/24/2019] [Indexed: 12/27/2022] Open
Abstract
The molecular pharmacology of artemisinin (ART)-based antimalarial drugs is incompletely understood. Clinically, these drugs are used in combination with longer lasting partner drugs in several different artemisinin combination therapies (ACTs). ACTs are currently the standard of care against Plasmodium falciparum malaria across much of the world. A harbinger of emerging artemisinin resistance (ARTR), known as the delayed clearance phenotype (DCP), has been well documented in South East Asia (SEA) and is beginning to affect the efficacy of some ACTs. Though several genetic mutations have been associated with ARTR/DCP, a molecular mechanism remains elusive. This paper summarizes our current understanding of ART molecular pharmacology and hypotheses for ARTR/DCP.
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Affiliation(s)
- Laura E Heller
- Departments of Chemistry and of Biochemistry and Cellular and Molecular Biology, Georgetown University, 37th and O Streets NW, Washington, DC 20057, USA.
| | - Paul D Roepe
- Departments of Chemistry and of Biochemistry and Cellular and Molecular Biology, Georgetown University, 37th and O Streets NW, Washington, DC 20057, USA.
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15
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Untaroiu AM, Carey MA, Guler JL, Papin JA. Leveraging the effects of chloroquine on resistant malaria parasites for combination therapies. BMC Bioinformatics 2019; 20:186. [PMID: 30987583 PMCID: PMC6466727 DOI: 10.1186/s12859-019-2756-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 03/19/2019] [Indexed: 11/10/2022] Open
Abstract
Background Malaria is a major global health problem, with the Plasmodium falciparum protozoan parasite causing the most severe form of the disease. Prevalence of drug-resistant P. falciparum highlights the need to understand the biology of resistance and to identify novel combination therapies that are effective against resistant parasites. Resistance has compromised the therapeutic use of many antimalarial drugs, including chloroquine, and limited our ability to treat malaria across the world. Fortunately, chloroquine resistance comes at a fitness cost to the parasite; this can be leveraged in developing combination therapies or to reinstate use of chloroquine. Results To understand biological changes induced by chloroquine treatment, we compared transcriptomics data from chloroquine-resistant parasites in the presence or absence of the drug. Using both linear models and a genome-scale metabolic network reconstruction of the parasite to interpret the expression data, we identified targetable pathways in resistant parasites. This study identified an increased importance of lipid synthesis, glutathione production/cycling, isoprenoids biosynthesis, and folate metabolism in response to chloroquine. Conclusions We identified potential drug targets for chloroquine combination therapies. Significantly, our analysis predicts that the combination of chloroquine and sulfadoxine-pyrimethamine or fosmidomycin may be more effective against chloroquine-resistant parasites than either drug alone; further studies will explore the use of these drugs as chloroquine resistance blockers. Additional metabolic weaknesses were found in glutathione generation and lipid synthesis during chloroquine treatment. These processes could be targeted with novel inhibitors to reduce parasite growth and reduce the burden of malaria infections. Thus, we identified metabolic weaknesses of chloroquine-resistant parasites and propose targeted chloroquine combination therapies. Electronic supplementary material The online version of this article (10.1186/s12859-019-2756-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ana M Untaroiu
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA.,Present address: Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, USA
| | - Maureen A Carey
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA.,Present address: Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Jennifer L Guler
- Department of Biology, University of Virginia, Charlottesville, VA, USA.
| | - Jason A Papin
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA.
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16
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Kumar S, Bhardwaj TR, Prasad DN, Singh RK. Drug targets for resistant malaria: Historic to future perspectives. Biomed Pharmacother 2018; 104:8-27. [PMID: 29758416 DOI: 10.1016/j.biopha.2018.05.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 04/22/2018] [Accepted: 05/07/2018] [Indexed: 01/05/2023] Open
Abstract
New antimalarial targets are the prime need for the discovery of potent drug candidates. In order to fulfill this objective, antimalarial drug researches are focusing on promising targets in order to develop new drug candidates. Basic metabolism and biochemical process in the malaria parasite, i.e. Plasmodium falciparum can play an indispensable role in the identification of these targets. But, the emergence of resistance to antimalarial drugs is an escalating comprehensive problem with the progress of antimalarial drug development. The development of resistance has highlighted the need for the search of novel antimalarial molecules. The pharmaceutical industries are committed to new drug development due to the global recognition of this life threatening resistance to the currently available antimalarial therapy. The recent developments in the understanding of parasite biology are exhilarating this resistance issue which is further being ignited by malaria genome project. With this background of information, this review was aimed to highlights and provides useful information on various present and promising treatment approaches for resistant malaria, new progresses, pursued by some innovative targets that have been explored till date. This review also discusses modern and futuristic multiple approaches to antimalarial drug discovery and development with pictorial presentations highlighting the various targets, that could be exploited for generating promising new drugs in the future for drug resistant malaria.
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Affiliation(s)
- Sahil Kumar
- School of Pharmacy and Emerging Sciences, Baddi University of Emerging Sciences & Technology, Baddi, Dist. Solan, 173205, Himachal Pradesh, India
| | - T R Bhardwaj
- School of Pharmacy and Emerging Sciences, Baddi University of Emerging Sciences & Technology, Baddi, Dist. Solan, 173205, Himachal Pradesh, India
| | - D N Prasad
- Department of Pharmaceutical Chemistry, Shivalik College of Pharmacy, Nangal, Dist. Rupnagar, 140126, Punjab, India
| | - Rajesh K Singh
- Department of Pharmaceutical Chemistry, Shivalik College of Pharmacy, Nangal, Dist. Rupnagar, 140126, Punjab, India.
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17
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McGovern OL, Rivera-Cuevas Y, Kannan G, Narwold AJ, Carruthers VB. Intersection of endocytic and exocytic systems in Toxoplasma gondii. Traffic 2018; 19:336-353. [PMID: 29437275 DOI: 10.1111/tra.12556] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 02/09/2018] [Accepted: 02/10/2018] [Indexed: 12/12/2022]
Abstract
Host cytosolic proteins are endocytosed by Toxoplasma gondii and degraded in its lysosome-like compartment, the vacuolar compartment (VAC), but the dynamics and route of endocytic trafficking remain undefined. Conserved endocytic components and plant-like features suggest T. gondii endocytic trafficking involves transit through early and late endosome-like compartments (ELCs) and potentially the trans-Golgi network (TGN) as in plants. However, exocytic trafficking to regulated secretory organelles, micronemes and rhoptries, also proceeds through ELCs and requires classical endocytic components, including a dynamin-related protein, DrpB. Here, we show that host cytosolic proteins are endocytosed within 7 minutes post-invasion, trafficked through ELCs en route to the VAC, and degraded within 30 minutes. We could not definitively interpret if ingested protein is trafficked through the TGN. We also found that parasites ingest material from the host cytosol throughout the parasite cell cycle. Ingested host proteins colocalize with immature microneme proteins, proM2AP and proMIC5, in transit to the micronemes, but not with the immature rhoptry protein proRON4, indicating that endocytic trafficking of ingested protein intersects with exocytic trafficking of microneme proteins. Finally, we show that conditional expression of a DrpB dominant negative mutant increases T. gondii ingestion of host-derived proteins, suggesting that DrpB is not required for parasite endocytosis.
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Affiliation(s)
- Olivia L McGovern
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Yolanda Rivera-Cuevas
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Geetha Kannan
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Andrew J Narwold
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, Michigan
| | - Vern B Carruthers
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, Michigan
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18
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Sherling ES, van Ooij C. Host cell remodeling by pathogens: the exomembrane system in Plasmodium-infected erythrocytes. FEMS Microbiol Rev 2017; 40:701-21. [PMID: 27587718 PMCID: PMC5007283 DOI: 10.1093/femsre/fuw016] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2016] [Indexed: 12/22/2022] Open
Abstract
Malaria is caused by infection of erythrocytes by parasites of the genus Plasmodium. To survive inside erythrocytes, these parasites induce sweeping changes within the host cell, one of the most dramatic of which is the formation of multiple membranous compartments, collectively referred to as the exomembrane system. As an uninfected mammalian erythrocyte is devoid of internal membranes, the parasite must be the force and the source behind the formation of these compartments. Even though the first evidence of the presence these of internal compartments was obtained over a century ago, their functions remain mostly unclear, and in some cases completely unknown, and the mechanisms underlying their formation are still mysterious. In this review, we provide an overview of the different parts of the exomembrane system, describing the parasitophorous vacuole, the tubovesicular network, Maurer's clefts, the caveola-vesicle complex, J dots and other mobile compartments, and the small vesicles that have been observed in Plasmodium-infected cells. Finally, we combine the data into a simplified view of the exomembrane system and its relation to the alterations of the host erythrocyte. Plasmodium parasites remodel the host erythrocyte in various ways, including the formation of several membranous compartments, together referred to as the exomembrane system, within the erythrocyte cytosol that together are key to the sweeping changes in the host cell.
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Affiliation(s)
- Emma S Sherling
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London NW7 1AA, UK Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Christiaan van Ooij
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London NW7 1AA, UK
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19
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Hamada Y, Kiso Y. New directions for protease inhibitors directed drug discovery. Biopolymers 2016; 106:563-79. [PMID: 26584340 PMCID: PMC7161749 DOI: 10.1002/bip.22780] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 10/25/2015] [Accepted: 11/02/2015] [Indexed: 12/29/2022]
Abstract
Proteases play crucial roles in various biological processes, and their activities are essential for all living organisms-from viruses to humans. Since their functions are closely associated with many pathogenic mechanisms, their inhibitors or activators are important molecular targets for developing treatments for various diseases. Here, we describe drugs/drug candidates that target proteases, such as malarial plasmepsins, β-secretase, virus proteases, and dipeptidyl peptidase-4. Previously, we reported inhibitors of aspartic proteases, such as renin, human immunodeficiency virus type 1 protease, human T-lymphotropic virus type I protease, plasmepsins, and β-secretase, as drug candidates for hypertension, adult T-cell leukaemia, human T-lymphotropic virus type I-associated myelopathy, malaria, and Alzheimer's disease. Our inhibitors are also described in this review article as examples of drugs that target proteases. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 563-579, 2016.
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Affiliation(s)
- Yoshio Hamada
- Medicinal Chemistry LaboratoryKobe Pharmaceutical University, MotoyamakitaHigashinada‐kuKobe658‐8558Japan
| | - Yoshiaki Kiso
- Laboratory of Peptide Science, Nagahama Institute of Bio‐Science and TechnologyTamura‐choNagahama526‐0829Japan
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20
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The prosegment catalyzes native folding of Plasmodium falciparum plasmepsin II. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:1356-62. [DOI: 10.1016/j.bbapap.2016.06.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/29/2016] [Accepted: 06/30/2016] [Indexed: 01/15/2023]
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21
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Recacha R, Jaudzems K, Akopjana I, Jirgensons A, Tars K. Crystal structure of Plasmodium falciparum proplasmepsin IV: the plasticity of proplasmepsins. Acta Crystallogr F Struct Biol Commun 2016; 72:659-66. [PMID: 27599854 PMCID: PMC5012203 DOI: 10.1107/s2053230x16011663] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 07/18/2016] [Indexed: 11/10/2022] Open
Abstract
Plasmepsin IV from Plasmodium falciparum (PM IV) is a promising target for the development of novel antimalarial drugs. Here, the crystal structure of the truncated zymogen of PM IV (pPM IV), consisting of the mature enzyme plus a prosegment of 47 residues, has been determined at 1.5 Å resolution. pPM IV presents the fold previously described for studied proplasmepsins, displaying closer similarities to proplasmepin IV from P. vivax (pPvPM) than to the other two proplasmepsins from P. falciparum. The study and comparison of the pPM IV structure with the proplasmepsin structures described previously provide information about the similarities and differences in the inactivation-activation mechanisms among the plasmepsin zymogens.
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Affiliation(s)
- Rosario Recacha
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga, LV-1006, Latvia
| | - Kristaps Jaudzems
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga, LV-1006, Latvia
| | - Inara Akopjana
- Biomedical Research and Study Centre, Ratsupites 1, Riga, LV-1067, 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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22
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Dimerization of Arginyl-tRNA Synthetase by Free Heme Drives Its Inactivation in Plasmodium falciparum. Structure 2016; 24:1476-87. [PMID: 27502052 DOI: 10.1016/j.str.2016.06.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 06/15/2016] [Accepted: 06/20/2016] [Indexed: 11/23/2022]
Abstract
Excess cellular heme is toxic, and malaria parasites regulate its levels during hemoglobin digestion. Aminoacyl-tRNA synthetases are ubiquitous enzymes, and of these, arginyl-tRNA synthetase (RRS) is unique as its enzymatic product of charged tRNA is required for protein synthesis and degradation. We show that Plasmodium falciparum arginyl-tRNA synthetase (PfRRS) is an active, cytosolic, and monomeric enzyme. Its high-resolution crystal structure highlights critical structural differences with the human enzyme. We further show that hemin binds to and inhibits the aminoacylation activity of PfRRS. Hemin induces a dimeric form of PfRRS that is thus rendered enzymatically dead as it is unable to recognize its cognate tRNA(arg). Excessive hemin in chloroquine-treated malaria parasites results in significantly reduced charged tRNA(arg) levels, thus suggesting deceleration of protein synthesis. These data together suggest that the inhibition of Plasmodium falciparum arginyl-tRNA synthetase can now be synergized with existing antimalarials for more potent drug cocktails against malaria parasites.
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Plasmodium falciparum ookinete expression of plasmepsin VII and plasmepsin X. Malar J 2016; 15:111. [PMID: 26911483 PMCID: PMC4765185 DOI: 10.1186/s12936-016-1161-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 02/10/2016] [Indexed: 12/17/2022] Open
Abstract
Background Plasmodium invasion of the mosquito midgut is a population bottleneck in the parasite lifecycle. Interference with molecular mechanisms by which the ookinete invades the mosquito midgut is one potential approach to developing malaria transmission-blocking strategies. Plasmodium aspartic proteases are one such class of potential targets: plasmepsin IV (known to be present in the asexual stage food vacuole) was previously shown to be involved in Plasmodium gallinaceum infection of the mosquito midgut, and plasmepsins VII and plasmepsin X (not known to be present in the asexual stage food vacuole) are upregulated in Plasmodium falciparum mosquito stages. These (and other) parasite-derived enzymes that play essential roles during ookinete midgut invasion are prime candidates for transmission-blocking vaccines. Methods Reverse transcriptase PCR (RT-PCR) was used to determine timing of P. falciparum plasmepsin VII (PfPM VII) and plasmepsin X (PfPM X) mRNA transcripts in parasite mosquito midgut stages. Protein expression was confirmed by western immunoblot and immunofluorescence assays (IFA) using anti-peptide monoclonal antibodies (mAbs) against immunogenic regions of PfPM VII and PfPM X. These antibodies were also used in standard membrane feeding assays (SMFA) to determine whether inhibition of these proteases would affect parasite transmission to mosquitoes. The Mann–Whitney U test was used to analyse mosquito transmission assay results. Results RT-PCR, western immunoblot and immunofluorescence assay confirmed expression of PfPM VII and PfPM X in mosquito stages. Whereas PfPM VII was expressed in zygotes and ookinetes, PfPM X was expressed in gametes, zygotes, and ookinetes. Antibodies against PfPM VII and PfPM X decreased P. falciparum invasion of the mosquito midgut when used at high concentrations, indicating that these proteases play a role in Plasmodium mosquito midgut invasion. Failure to generate genetic knockouts of these genes limited determination of the precise role of these proteases in parasite transmission but suggests that they are essential during the intraerythrocytic life cycle. Conclusions PfPM VII and PfPM X are present in the mosquito-infective stages of P. falciparum. Standard membrane feeding assays demonstrate that antibodies against these proteins reduce the infectivity of P. falciparum for mosquitoes, suggesting their viability as transmission-blocking vaccine candidates. Further study of the role of these plasmepsins in P. falciparum biology is warranted. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1161-5) contains supplementary material, which is available to authorized users.
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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] [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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25
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McGillewie L, Soliman ME. Flap flexibility amongst plasmepsins I, II, III, IV, and V: Sequence, structural, and molecular dynamics analyses. Proteins 2015; 83:1693-705. [PMID: 26146842 DOI: 10.1002/prot.24855] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 06/09/2015] [Accepted: 06/22/2015] [Indexed: 11/05/2022]
Abstract
Herein, for the first time, we comparatively report the opening and closing of apo plasmepsin I - V. Plasmepsins belong the aspartic protease family of enzymes, and are expressed during the various stages of the P. falciparum lifecycle, the species responsible for the most lethal and virulent malaria to infect humans. Plasmepsin I, II, IV and HAP degrade hemoglobin from infected red blood cells, whereas plasmepsin V transport proteins crucial to the survival of the malaria parasite across the endoplasmic reticulum. Flap-structures covering the active site of aspartic proteases (such as HIV protease) are crucial to the conformational flexibility and dynamics of the protein, and ultimately control the binding landscape. The flap-structure in plasmepsins is made up of a flip tip in the N-terminal lying perpendicular to the active site, adjacent to the flexible loop region in the C-terminal. Using molecular dynamics, we propose three parameters to better describe the opening and closing of the flap-structure in apo plasmepsins. Namely, the distance, d1, between the flap tip and the flexible region; the dihedral angle, ϕ, to account for the twisting motion; and the TriCα angle, θ1. Simulations have shown that as the flap-structure twists, the flap and flexible region move apart opening the active site, or move toward each other closing the active site. The data from our study indicate that of all the plasmepsins investigated in the present study, Plm IV and V display the highest conformational flexibility and are more dynamic structures versus Plm I, II, and HAP.
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Affiliation(s)
- Lara McGillewie
- Molecular Modelling & Drug Design Research Group, School of Health Sciences, University of KwaZulu-Natal, Westville, Durban, 4001, South Africa
| | - Mahmoud E Soliman
- Molecular Modelling & Drug Design Research Group, School of Health Sciences, University of KwaZulu-Natal, Westville, Durban, 4001, South Africa
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Huizing AP, Mondal M, Hirsch AKH. Fighting malaria: structure-guided discovery of nonpeptidomimetic plasmepsin inhibitors. J Med Chem 2015; 58:5151-63. [PMID: 25719272 DOI: 10.1021/jm5014133] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Plasmepsins (Plms) are aspartic proteases involved in the degradation of human hemoglobin by Plasmodium falciparum. Given that the parasite needs the resulting amino acid building blocks for its growth and development, plasmepsins are an important antimalarial drug target. Over the past decade, tremendous progress has been achieved in the development of inhibitors of plasmepsin using two strategies: structure-based drug design (SBDD) and structure-based virtual screening (SBVS). Herein, we review the inhibitors of Plms I-IV developed by SBDD or SBVS with a particular focus on obtaining selectivity versus the human Asp proteases cathepsins and renin and activity in cell-based assays. By use of SBDD, the flap pocket of Plm II has been discovered and constitutes a convenient handle to obtain selectivity. In SBVS, activity against Plms I-IV and selectivity versus cathepsins are not always taken into account. A combination of SBVS, SBDD, and molecular dynamics simulations opens up opportunities for future design cycles.
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Affiliation(s)
- Anja P Huizing
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 7, NL-9747 AG Groningen, The Netherlands
| | - Milon Mondal
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 7, NL-9747 AG Groningen, The Netherlands
| | - Anna K H Hirsch
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 7, NL-9747 AG Groningen, The Netherlands
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Phagocytic uptake of oxidized heme polymer is highly cytotoxic to macrophages. PLoS One 2014; 9:e103706. [PMID: 25078090 PMCID: PMC4117526 DOI: 10.1371/journal.pone.0103706] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 07/06/2014] [Indexed: 11/26/2022] Open
Abstract
Apoptosis in macrophages is responsible for immune-depression and pathological effects during malaria. Phagocytosis of PRBC causes induction of apoptosis in macrophages through release of cytosolic factors from infected cells. Heme polymer or β-hematin causes dose-dependent death of macrophages with LC50 of 132 µg/ml and 182 µg/ml respectively. The toxicity of hemin or heme polymer was amplified several folds in the presence of non-toxic concentration of methemoglobin. β-hematin uptake in macrophage through phagocytosis is crucial for enhanced toxicological effects in the presence of methemoglobin. Higher accumulation of β-hematin is observed in macrophages treated with β-hematin along with methemoglobin. Light and scanning electron microscopic observations further confirm accumulation of β-hematin with cellular toxicity. Toxicological potentiation of pro-oxidant molecules toward macrophages depends on generation of H2O2 and independent to release of free iron from pro-oxidant molecules. Methemoglobin oxidizes β-hematin to form oxidized β-hematin (βH*) through single electron transfer mechanism. Pre-treatment of reaction mixture with spin-trap Phenyl-N-t-butyl-nitrone dose-dependently reverses the β-hematin toxicity, indicates crucial role of βH* generation with the toxicological potentiation. Acridine orange/ethidium bromide staining and DNA fragmentation analysis indicate that macrophage follows an oxidative stress dependent apoptotic pathway to cause death. In summary, current work highlights mutual co-operation between methemoglobin and different pro-oxidant molecules to enhance toxicity towards macrophages. Hence, methemoglobin peroxidase activity can be probed for subduing cellular toxicity of pro-oxidant molecules and it may in-turn make up for host immune response against the malaria parasite.
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Miura T, Hidaka K, Azai Y, Kashimoto K, Kawasaki Y, Chen SE, de Freitas RF, Freire E, Kiso Y. Optimization of plasmepsin inhibitor by focusing on similar structural feature with chloroquine to avoid drug-resistant mechanism of Plasmodium falciparum. Bioorg Med Chem Lett 2014; 24:1698-701. [DOI: 10.1016/j.bmcl.2014.02.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 02/12/2014] [Accepted: 02/19/2014] [Indexed: 11/17/2022]
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Lolupiman S, Siripurkpong P, Yuvaniyama J. Disulfide linkages in Plasmodium falciparum plasmepsin-i are essential elements for its processing activity and multi-milligram recombinant production yield. PLoS One 2014; 9:e89424. [PMID: 24586769 PMCID: PMC3930733 DOI: 10.1371/journal.pone.0089424] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 01/21/2014] [Indexed: 11/18/2022] Open
Abstract
Plasmodium falciparum plasmepsin-I (PM-I) has been considered a potential drug target for the parasite that causes fatal malaria in human. Determination of PM-I structures for rational design of its inhibitors is hindered by the difficulty in obtaining large quantity of soluble enzyme. Nearly all attempts for its heterologous expression in Escherichia coli result in the production of insoluble proteins in both semi-pro-PM-I and its truncated form, and thus require protein refolding. Moreover, the yields of purified, soluble PM-I from all reported studies are very limited. Exclusion of truncated semi-pro-PM-I expression in E. coli C41(DE3) is herein reported. We also show that the low preparation yield of purified semi-pro-PM-I with autoprocessing ability is mainly a result of structural instability of the refolded enzyme in acidic conditions due to incomplete formation of disulfide linkages. Upon formation of at least one of the two natural disulfide bonds, nearly all of the refolded semi-pro-PM-I could be activated to its mature form. A significantly improved yield of 10 mg of semi-pro-PM-I per liter of culture, which resulted in 6-8 mg of the mature PM-I, was routinely obtained using this strategy.
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Affiliation(s)
- Sirisak Lolupiman
- Department of Biochemistry and Center for Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Pilaiwan Siripurkpong
- Department of Medical Technology, Faculty of Allied Health Sciences, Thammasat University, Pathumthani, Thailand
| | - Jirundon Yuvaniyama
- Department of Biochemistry and Center for Excellence in Protein Structure and Function, Faculty of Science, Mahidol University, Bangkok, Thailand
- * E-mail:
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Coronado LM, Nadovich CT, Spadafora C. Malarial hemozoin: from target to tool. Biochim Biophys Acta Gen Subj 2014; 1840:2032-41. [PMID: 24556123 DOI: 10.1016/j.bbagen.2014.02.009] [Citation(s) in RCA: 145] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 01/26/2014] [Accepted: 02/10/2014] [Indexed: 02/07/2023]
Abstract
BACKGROUND Malaria is an extremely devastating disease that continues to affect millions of people each year. A distinctive attribute of malaria infected red blood cells is the presence of malarial pigment or the so-called hemozoin. Hemozoin is a biocrystal synthesized by Plasmodium and other blood-feeding parasites to avoid the toxicity of free heme derived from the digestion of hemoglobin during invasion of the erythrocytes. SCOPE OF REVIEW Hemozoin is involved in several aspects of the pathology of the disease as well as in important processes such as the immunogenicity elicited. It is known that the once best antimalarial drug, chloroquine, exerted its effect through interference with the process of hemozoin formation. In the present review we explore what is known about hemozoin, from hemoglobin digestion, to its final structural analysis, to its physicochemical properties, its role in the disease and notions of the possible mechanisms that could kill the parasite by disrupting the synthesis or integrity of this remarkable crystal. MAJOR CONCLUSIONS The importance and peculiarities of this biocrystal have given researchers a cause to consider it as a target for new antimalarials and to use it through unconventional approaches for diagnostics and therapeutics against the disease. GENERAL SIGNIFICANCE Hemozoin plays an essential role in the biology of malarial disease. Innovative ideas could use all the existing data on the unique chemical and biophysical properties of this macromolecule to come up with new ways of combating malaria.
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Affiliation(s)
- Lorena M Coronado
- Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, Ciudad del Saber, Panama; Department of Biotechnology, Acharya Nagarjuna University, Guntur 522 510, A.P., India
| | | | - Carmenza Spadafora
- Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, Ciudad del Saber, Panama.
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An aspartic protease of the scabies mite Sarcoptes scabiei is involved in the digestion of host skin and blood macromolecules. PLoS Negl Trop Dis 2013; 7:e2525. [PMID: 24244770 PMCID: PMC3820722 DOI: 10.1371/journal.pntd.0002525] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 09/27/2013] [Indexed: 11/19/2022] Open
Abstract
Background Scabies is a disease of worldwide significance, causing considerable morbidity in both humans and other animals. The scabies mite Sarcoptes scabiei burrows into the skin of its host, obtaining nutrition from host skin and blood. Aspartic proteases mediate a range of diverse and essential physiological functions such as tissue invasion and migration, digestion, moulting and reproduction in a number of parasitic organisms. We investigated whether aspartic proteases may play role in scabies mite digestive processes. Methodology/Principle Findings We demonstrated the presence of aspartic protease activity in whole scabies mite extract. We then identified a scabies mite aspartic protease gene sequence and produced recombinant active enzyme. The recombinant scabies mite aspartic protease was capable of digesting human haemoglobin, serum albumin, fibrinogen and fibronectin, but not collagen III or laminin. This is consistent with the location of the scabies mites in the upper epidermis of human skin. Conclusions/Significance The development of novel therapeutics for scabies is of increasing importance given the evidence of emerging resistance to current treatments. We have shown that a scabies mite aspartic protease plays a role in the digestion of host skin and serum molecules, raising the possibility that interference with the function of the enzyme may impact on mite survival. Scabies is an infectious disease of the skin caused by infestation with the parasitic mite Sarcoptes scabiei. It is a disease that has a considerable impact on humans and other animals, including livestock, wildlife and companion animals. Scabies mites burrow into the skin of their host, consuming host skin and blood molecules. Aspartic proteases play a key role in invasion and digestion processes in many parasitic organisms. We have identified a scabies mite aspartic protease and have shown that it is capable of digesting human haemoglobin, serum albumin, fibrinogen and fibronectin in vitro, indicating that it plays a role in mite digestive processes. This raises the possibility that interfering with the function of this digestive enzyme may impact on mite survival.
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Trafficked Proteins-Druggable in Plasmodium falciparum? Int J Cell Biol 2013; 2013:435981. [PMID: 23710183 PMCID: PMC3655585 DOI: 10.1155/2013/435981] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Accepted: 03/12/2013] [Indexed: 01/09/2023] Open
Abstract
Malaria is an infectious disease that results in serious health problems in the countries in which it is endemic. Annually this parasitic disease leads to more than half a million deaths; most of these are children in Africa. An effective vaccine is not available, and the treatment of the disease is solely dependent on chemotherapy. However, drug resistance is spreading, and the identification of new drug targets as well as the development of new antimalarials is urgently required. Attention has been drawn to a variety of essential plasmodial proteins, which are targeted to intra- or extracellular destinations, such as the digestive vacuole, the apicoplast, or into the host cell. Interfering with the action or the transport of these proteins will impede proliferation of the parasite. In this mini review, we will shed light on the present discovery of chemotherapeutics and potential drug targets involved in protein trafficking processes in the malaria parasite.
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Deponte M, Hoppe HC, Lee MC, Maier AG, Richard D, Rug M, Spielmann T, Przyborski JM. Wherever I may roam: Protein and membrane trafficking in P. falciparum-infected red blood cells. Mol Biochem Parasitol 2012; 186:95-116. [DOI: 10.1016/j.molbiopara.2012.09.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Revised: 09/21/2012] [Accepted: 09/24/2012] [Indexed: 11/27/2022]
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Denloye T, Dalal S, Klemba M. Characterization of a glycerophosphodiesterase with an unusual tripartite distribution and an important role in the asexual blood stages of Plasmodium falciparum. Mol Biochem Parasitol 2012; 186:29-37. [PMID: 23000576 DOI: 10.1016/j.molbiopara.2012.09.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Revised: 09/06/2012] [Accepted: 09/12/2012] [Indexed: 10/27/2022]
Abstract
Catabolism of glycerophospholipids during the rapid growth of the asexual intraerythrocytic malaria parasite may contribute to membrane recycling and the acquisition of lipid biosynthetic precursors from the host. To better understand the scope of lipid catabolism in Plasmodium falciparum, we have characterized a malarial homolog of bacterial glycerophosphodiesterases. These enzymes catalyze the hydrolysis of glycerophosphodiesterases that are generated by phospholipase-catalyzed removal of the two acyl groups from glycerophospholipids. The P. falciparum glycerophosphodiesterase (PfGDPD) exhibits an unusual tripartite distribution during the asexual blood stage with pools of enzyme in the parasitophorous vacuole, food vacuole and cytosol. Efforts to disrupt the chromosomal PfGDPD coding sequence were unsuccessful, which implies that the enzyme is important for efficient parasite growth. Tagging of the endogenous pool of PfGDPD with a conditional aggregation domain partially perturbed the distribution of the enzyme in the parasitophorous vacuole but had no discernable effect on growth in culture. Kinetic characterization of the hydrolysis of glycerophosphocholine by recombinant PfGDPD, an Mg(2+)-dependent enzyme, yielded steady-state parameters that were comparable to those of a homologous bacterial glycerophosphodiesterase. Together, these results suggest a physiological role for PfGDPD in glycerophospholipid catabolism in multiple subcellular compartments. Possibilities for what this role might be are discussed.
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Affiliation(s)
- Titilola Denloye
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
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Munkhjargal T, AbouLaila M, Terkawi MA, Sivakumar T, Ichikawa M, Davaasuren B, Nyamjargal T, Yokoyama N, Igarashi I. Inhibitory effects of pepstatin A and mefloquine on the growth of Babesia parasites. Am J Trop Med Hyg 2012; 87:681-8. [PMID: 22890034 DOI: 10.4269/ajtmh.2012.12-0218] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
We evaluated the inhibitory effects of pepstatin A and mefloquine on the in vitro and in vivo growths of Babesia parasites. The in vitro growth of Babesia bovis, B. bigemina, B. caballi, and B. equi was significantly inhibited (P < 0.05) by micromolar concentrations of pepstatin A (50% inhibitory concentrations = 38.5, 36.5, 17.6, and 18.1 μM, respectively) and mefloquine (50% inhibitory concentrations = 59.7, 56.7, 20.7, and 4 μM, respectively). Furthermore, both reagents either alone at a concentration of 5 mg/kg or in combinations (2.5/2.5 and 5/5 mg/kg) for 10 days significantly inhibited the in vivo growth of B. microti in mice. Mefloquine treatment was highly effective and the combination treatments were less effective than other treatments. Therefore, mefloquine may antagonize the actions of pepstatin A against babesiosis and aspartic proteases may play an important role in the asexual growth cycle of Babesia parasites.
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Affiliation(s)
- Tserendorj Munkhjargal
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido, Japan.
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Almeida CM, Pereira C, da Costa DS, Pereira S, Pissarra J, Simões I, Faro C. Chlapsin, a chloroplastidial aspartic proteinase from the green algae Chlamydomonas reinhardtii. PLANTA 2012; 236:283-296. [PMID: 22349731 DOI: 10.1007/s00425-012-1605-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 01/26/2012] [Indexed: 05/31/2023]
Abstract
Aspartic proteinases have been extensively characterized in land plants but up to now no evidences for their presence in green algae group have yet been reported in literature. Here we report on the identification of the first (and only) typical aspartic proteinase from Chlamydomonas reinhardtii. This enzyme, named chlapsin, was shown to maintain the primary structure organization of typical plant aspartic proteinases but comprising distinct features, such as similar catalytic motifs DTG/DTG resembling those from animal and microbial counterparts, and an unprecedentedly longer plant specific insert domain with an extra segment of 80 amino acids, rich in alanine residues. Our results also demonstrated that chlapsin accumulates in Chlamydomonas chloroplast bringing this new enzyme to a level of uniqueness among typical plant aspartic proteinases. Chlapsin was successfully expressed in Escherichia coli and it displayed the characteristic enzymatic properties of typical aspartic proteinases, like optimum activity at acidic pH and complete inhibition by pepstatin A. Another difference to plant aspartic proteinases emerged as chlapsin was produced in an active form without its putative prosegment domain. Moreover, recombinant chlapsin showed a restricted enzymatic specificity and a proteolytic activity influenced by the presence of redox agents and nucleotides, further differentiating it from typical plant aspartic proteinases and anticipating a more specialized/regulated function for this Chlamydomonas enzyme. Taken together, our results revealed a pattern of complexity for typical plant aspartic proteinases in what concerns sequence features, localization and biochemical properties, raising new questions on the evolution and function of this vast group of plant enzymes.
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Affiliation(s)
- Carla Malaquias Almeida
- Biocant, Biotechnology Innovation Center, Molecular Biotechnology Unit, Parque Tecnológico de Cantanhede, Núcleo 4 Lote 3, 3060-197, Cantanhede, Portugal
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Nag S, Prasad KMN, Trivedi V. Identification and screening of antimalarial phytochemical reservoir from northeastern Indian plants to develop PfRIO-2 kinase inhibitor. Eur Food Res Technol 2012. [DOI: 10.1007/s00217-012-1692-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Trivedi V, Nag S. In silico characterization of atypical kinase PFD0975w from Plasmodium kinome: a suitable target for drug discovery. Chem Biol Drug Des 2012; 79:600-9. [PMID: 22233458 DOI: 10.1111/j.1747-0285.2012.01321.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
RIO-2 kinase is known to regulate ribosome biogenesis and other cell cycle events. The 3D model of ATP bound and an unbound form of PFD0975w was generated using AfRIO-2 crystal structure 1TQI, 1ZAO as template employing Modeller9v7 program. Structural characterization identified N-terminal winged helix domain (1-84), C-terminal kinase domain (148-275), and presence of other critical residues known for ATP binding and kinase activity. Using Q-site and pocket finder, a number of well-defined substrate (peptide) binding regions were identified in the catalytic core of the protein. The peptide binding regions were further validated by molecular modeling a non-specific polyalanine peptide and a sequence-specific peptide2 into these sites to generate a stable PFD0975w/peptide complexes. Peptide fits well into identified pocket on PFD0975w and makes extensive interaction with the protein residues. These newly identified peptide binding sites potentially give opportunity to design a specific inhibitor against PFD0975w. There are subtle but significant differences between Plasmodium falciparum and human RIO-2 to exploit PFD0975w for drug development. In conclusion, our finding will let us to design effective chemotherapy against malaria parasite exploiting PFD0975w as a drug target.
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Affiliation(s)
- Vishal Trivedi
- Department of Biotechnology, Malaria Research Group, Indian Institute of Technology-Guwahati, Guwahati-781039, Assam, India.
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Fischer K, Holt D, Currie B, Kemp D. Scabies: important clinical consequences explained by new molecular studies. ADVANCES IN PARASITOLOGY 2012; 79:339-73. [PMID: 22726646 DOI: 10.1016/b978-0-12-398457-9.00005-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In 2004, we reviewed the status of disease caused by the scabies mite Sarcoptes scabiei at the time and pointed out that very little basic research had ever been done. The reason for this was largely the lack of availability of mites for experimental purposes and, to a degree, a consequent lack of understanding of its importance, resulting in the trivial name 'itch mite'. Scabies is responsible for major morbidity in disadvantaged communities and immunocompromised patients worldwide. In addition to the physical discomfort caused by the disease, scabies infestations facilitate infection by bacterial pathogens such as Streptococcus pyogenes and Staphylococcus aureus via skin lesions, resulting in severe downstream disease such as in a high prevalence of rheumatic fever/heart disease in affected communities. We now have further evidence that in disadvantaged populations living in tropical climates, scabies rather than 'Strep throat' is an important source of S. pyogenes causing rheumatic fever and eventually rheumatic heart disease. In addition, our work has resulted in two fundamental research tools that facilitate much of the current biomedical research efforts on scabies, namely a public database containing ~45,000 scabies mite expressed sequence tags and a porcine in vivo model. Here we will discuss novel and unexpected proteins encountered in the database that appear crucial to mite survival with regard to digestion and evasion of host defence. The mode(s) of action of some of these have been at least partially revealed. Further, newly discovered molecules that may well have a similar role, such as a family of inactivated cysteine proteases, are yet to be investigated. Hence, there are now whole families of potential targets for chemical inhibitors of S. scabiei. These efforts put today's scabies research in a unique position to design and test small molecules that may specifically interfere with mite-derived molecules, such as digestive proteases and mite complement inhibitors. The porcine scabies model will be available to trial in vivo treatment with potential inhibitors. New therapies for scabies may be developed from these studies and may contribute to reduce the spread of scabies and the subsequent prevalence of bacterial skin infections and their devastating sequelae in the community.
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Affiliation(s)
- Katja Fischer
- Queensland Institute of Medical Research, Herston, Austraria
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Xiao H, Dee D, Yada RY. The native conformation of plasmepsin II is kinetically trapped at neutral pH. Arch Biochem Biophys 2011; 513:102-9. [PMID: 21767524 DOI: 10.1016/j.abb.2011.06.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 06/29/2011] [Accepted: 06/30/2011] [Indexed: 10/18/2022]
Abstract
Plasmepsin II (PMII), an aspartic protease from the malarial parasite Plasmodium falciparum, represents a model for understanding protease structure/function relationships due to its unique structure and properties. The present study undertook a thermodynamic and kinetic analysis of the PMII folding mechanism and a pH stability profile. Differential scanning calorimetry revealed that the native state of PMII (Np) was irreversibly unfolded, and in the pH range of 6.5-8.0, PMII refolds to a denatured state (Rp) with higher thermal stability than Np. Rp could also be formed upon partially unfolding PMII at pH 11.0 and 37 °C for 2h, followed by adjustment to a pH in the range of 6.5-8.0. While Rp could be folded/unfolded reversibly, Np was shown to exist as a kinetically trapped state. By examining the unfolding kinetics of Np and the kinetics of Rp folding to Np at 25 °C, it was found that Np is kinetically trapped by an unfolding barrier of 25.5 kcal/mol, and yet once unfolded, is prevented from folding by a comparable folding barrier. The folding mechanism of PMII is similar to that reported for pepsin. It is hypothesized that the PMII zymogen also utilizes a prosegment-catalyzed folding mechanism.
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Affiliation(s)
- Huogen Xiao
- Department of Food Science, University of Guelph, Guelph, Ontario, Canada N1G2W1
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Agarwal S, Kern S, Halbert J, Przyborski JM, Baumeister S, Dandekar T, Doerig C, Pradel G. Two nucleus-localized CDK-like kinases with crucial roles for malaria parasite erythrocytic replication are involved in phosphorylation of splicing factor. J Cell Biochem 2011; 112:1295-310. [PMID: 21312235 DOI: 10.1002/jcb.23034] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The kinome of the human malaria parasite Plasmodium falciparum comprises representatives of most eukaryotic protein kinase groups, including kinases which regulate proliferation and differentiation processes. Despite extensive research on most plasmodial enzymes, little information is available regarding the four identified members of the cyclin-dependent kinase-like kinase (CLK) family. In other eukaryotes, CLKs regulate mRNA splicing through phosphorylation of Serine/Arginine-rich proteins. Here, we investigate two of the PfCLKs, the Lammer kinase homolog PfCLK-1, and PfCLK-2. Both PfCLKs show homology with the yeast Serine/Arginine protein kinase Sky1p and are transcribed throughout the asexual blood stages and in gametocytes. PfCLK-1/Lammer possesses two nuclear localization signal sites and PfCLK-2 possesses one of these signal sites upstream of the C-terminal catalytic domains. Indirect immunofluorescence, Western blot, and electron microscopy data confirm that the kinases are primarily localized in the parasite nucleus, and PfCLK-2 is further present in the cytoplasm. The two kinases are important for completion of the asexual replication cycle of P. falciparum, as demonstrated by reverse genetics approaches. In vitro kinase assays show substrate phosphorylation by the PfCLKs, including the Sky1p substrate, splicing factor Npl3p, and the plasmodial alternative splicing factor PfASF-1. Mass spectrometric analysis of co-immunoprecipitated proteins indicates assembly of the two PfCLKs with proteins with predicted nuclease, phosphatase, or helicase functions. Our data indicate a crucial role of PfCLKs for malaria blood stage parasites, presumably by participating in gene regulation through the post-transcriptional modification of mRNA.
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Affiliation(s)
- Shruti Agarwal
- Research Center for Infectious Diseases, University of Würzburg, Josef-Schneider-Strasse 2, Building D15, 97080 Würzburg, Germany
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Gautam P, Upadhyay SK, Hassan W, Madan T, Sirdeshmukh R, Sundaram CS, Gade WN, Basir SF, Singh Y, Sarma PU. Transcriptomic and Proteomic Profile of Aspergillus fumigatus on Exposure to Artemisinin. Mycopathologia 2011; 172:331-46. [DOI: 10.1007/s11046-011-9445-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 06/27/2011] [Indexed: 12/11/2022]
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Ojha PK, Roy K. Exploring molecular docking and QSAR studies of plasmepsin-II inhibitor di-tertiary amines as potential antimalarial compounds. MOLECULAR SIMULATION 2011. [DOI: 10.1080/08927022.2010.548384] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Probir Kumar Ojha
- a Drug Theoretics and Cheminformatics Laboratory, Division of Medicinal and Pharmaceutical Chemistry, Department of Pharmaceutical Technology , Jadavpur University , Kolkata, India
| | - Kunal Roy
- a Drug Theoretics and Cheminformatics Laboratory, Division of Medicinal and Pharmaceutical Chemistry, Department of Pharmaceutical Technology , Jadavpur University , Kolkata, India
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Computational perspectives into plasmepsins structure-function relationship: implications to inhibitors design. J Trop Med 2011; 2011:657483. [PMID: 21760810 PMCID: PMC3134243 DOI: 10.1155/2011/657483] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 05/01/2011] [Accepted: 05/03/2011] [Indexed: 11/20/2022] Open
Abstract
The development of efficient and selective antimalariais remains a challenge for the pharmaceutical industry. The aspartic proteases plasmepsins, whose inhibition leads to parasite death, are classified as targets for the design of potent drugs. Combinatorial synthesis is currently being used to generate inhibitor libraries for these enzymes, and together with computational methodologies have been demonstrated capable for the selection of lead compounds. The high structural flexibility of plasmepsins, revealed by their X-ray structures and molecular dynamics simulations, made even more complicated the prediction of putative binding modes, and therefore, the use of common computational tools, like docking and free-energy calculations. In this review, we revised the computational strategies utilized so far, for the structure-function relationship studies concerning the plasmepsin family, with special focus on the recent advances in the improvement of the linear interaction estimation (LIE) method, which is one of the most successful methodologies in the evaluation of plasmepsin-inhibitor binding affinity.
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Silva NDF, Lameira J, Alves CN. A quantum mechanical/molecular mechanical study of the aspartic protease plasmepsin IV complexed with allophenylnorstatine-based inhibitor. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.04.085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Bhaumik P, Gustchina A, Wlodawer A. Structural studies of vacuolar plasmepsins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1824:207-23. [PMID: 21540129 DOI: 10.1016/j.bbapap.2011.04.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2011] [Revised: 04/11/2011] [Accepted: 04/12/2011] [Indexed: 10/18/2022]
Abstract
Plasmepsins (PMs) are pepsin-like aspartic proteases present in different species of parasite Plasmodium. Four Plasmodium spp. (P. vivax, P. ovale, P. malariae, and the most lethal P. falciparum) are mainly responsible for causing human malaria that affects millions worldwide. Due to the complexity and rate of parasite mutation coupled with regional variations, and the emergence of P. falciparum strains which are resistant to antimalarial agents such as chloroquine and sulfadoxine/pyrimethamine, there is constant pressure to find new and lasting chemotherapeutic drug therapies. Since many proteases represent therapeutic targets and PMs have been shown to play an important role in the survival of parasite, these enzymes have recently been identified as promising targets for the development of novel antimalarial drugs. The genome of P. falciparum encodes 10 PMs (PMI, PMII, PMIV-X and histo-aspartic protease (HAP)), 4 of which (PMI, PMII, PMIV and HAP) reside within the food vacuole, are directly involved in degradation of human hemoglobin, and share 50-79% amino acid sequence identity. This review focuses on structural studies of only these four enzymes, including their orthologs in other Plasmodium spp.. Almost all original crystallographic studies were performed with PMII, but more recent work on PMIV, PMI, and HAP resulted in a more complete picture of the structure-function relationship of vacuolar PMs. Many structures of inhibitor complexes of vacuolar plasmepsins, as well as their zymogens, have been reported in the last 15 years. Information gained by such studies will be helpful for the development of better inhibitors that could become a new class of potent antimalarial drugs. This article is part of a Special Issue entitled: Proteolysis 50 years after the discovery of lysosome.
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Affiliation(s)
- Prasenjit Bhaumik
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD 21702, USA
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Bhaumik P, Horimoto Y, Xiao H, Miura T, Hidaka K, Kiso Y, Wlodawer A, Yada RY, Gustchina A. Crystal structures of the free and inhibited forms of plasmepsin I (PMI) from Plasmodium falciparum. J Struct Biol 2011; 175:73-84. [PMID: 21521654 DOI: 10.1016/j.jsb.2011.04.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 04/08/2011] [Accepted: 04/14/2011] [Indexed: 11/28/2022]
Abstract
Plasmepsin I (PMI) is one of the four vacuolar pepsin-like proteases responsible for hemoglobin degradation by the malarial parasite Plasmodium falciparum, and the only one with no crystal structure reported to date. Due to substantial functional redundancy of these enzymes, lack of inhibition of even a single plasmepsin can defeat efforts in creating effective antiparasitic agents. We have now solved crystal structures of the recombinant PMI as apoenzyme and in complex with the potent peptidic inhibitor, KNI-10006, at the resolution of 2.4 and 3.1Å, respectively. The apoenzyme crystallized in the orthorhombic space group P2(1)2(1)2(1) with two molecules in the asymmetric unit and the structure has been refined to the final R-factor of 20.7%. The KNI-10006 bound enzyme crystallized in the tetragonal space group P4(3) with four molecules in the asymmetric unit and the structure has been refined to the final R-factor of 21.1%. In the PMI-KNI-10006 complex, the inhibitors were bound identically to all four enzyme molecules, with the opposite directionality of the main chain of KNI-10006 relative to the direction of the enzyme substrates. Such a mode of binding of inhibitors containing an allophenylnorstatine-dimethylthioproline insert in the P1-P1' positions, previously reported in a complex with PMIV, demonstrates the importance of satisfying the requirements for the proper positioning of the functional groups in the mechanism-based inhibitors towards the catalytic machinery of aspartic proteases, as opposed to binding driven solely by the specificity of the individual enzymes. A comparison of the structure of the PMI-KNI-10006 complex with the structures of other vacuolar plasmepsins identified the important differences between them and may help in the design of specific inhibitors targeting the individual enzymes.
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Affiliation(s)
- Prasenjit Bhaumik
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD 21702, USA
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Affiliation(s)
- P Olliaro
- UNDP/World Bank /WHO Special Programme for Research and Training in Tropical Diseases (TDR), Geneva, Switzerland
| | - D Wirth
- UNDP/World Bank /WHO Special Programme for Research and Training in Tropical Diseases (TDR), Geneva, Switzerland
- Harvard School of Tropical Public Health, Boston MA, USA
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Affiliation(s)
- Robert G Ridley
- F. Hoffmann-La Roche, Pharmaceuticals Division, Pharma Research, CH-4070 Basel, Switzerland
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McKay PB, Peters MB, Carta G, Flood CT, Dempsey E, Bell A, Berry C, Lloyd DG, Fayne D. Identification of plasmepsin inhibitors as selective anti-malarial agents using ligand based drug design. Bioorg Med Chem Lett 2011; 21:3335-41. [PMID: 21531557 DOI: 10.1016/j.bmcl.2011.04.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 04/01/2011] [Accepted: 04/03/2011] [Indexed: 12/25/2022]
Abstract
We describe the application of ligand based virtual screening technologies towards the discovery of novel plasmepsin (PM) inhibitors, a family of malarial parasitic aspartyl proteases. Pharmacophore queries were used to screen vendor libraries in search of active and selective compounds. The virtual hits were biologically assessed for activity and selectivity using whole cell Plasmodium falciparum parasites and on target in PM II, PM IV and the closely related human homologue, Cathepsin D assays. Here we report the virtual screening highlights, structures of the hits and their demonstrated biological activity.
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Affiliation(s)
- Paul B McKay
- Molecular Design Group, School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland
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