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Jiatsa Mbouna CD, Tchatat Tali BM, Tsouh Fokou PV, Madiesse Kemgne EA, Keumoe R, Toghueo Kouipou RM, Yamthe Tchokouaha LR, Tchuente Tchuenmogne MA, Kenou DK, Sahal D, Boyom FF. Specific sub fractions from Terminalia mantaly (H. Perrier) extracts potently inhibit Plasmodium falciparum rings, merozoite egress and invasion. J Ethnopharmacol 2022; 285:114909. [PMID: 34902534 DOI: 10.1016/j.jep.2021.114909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Terminalia mantaly (H. Perrier) and Terminalia superba (Engl. & Diels) are sources of treatment for various diseases, including malaria and/or related symptoms in parts of Southwestern Cameroon. However, there is limited information on the extent of the antiplasmodial potential of their extracts. AIM OF THE STUDY The present study was designed to investigate the antiplasmodial potential of chromatographic sub fractions (SFs) from promising fractions of Terminalia mantaly (Tm) [TmsbwChl, the chloroform fraction from water extract of Tm, IC50 (μg/mL) PfINDO: 0.56, Pf3D7: 1.12; SI > 357 (HEK/PfINDO) & 178 (HEK/Pf3D7)] and Terminalia superba (Ts) [TsrmEA, the ethyl acetate fraction from methanolic extract of Ts, IC50 (μg/mL) PfINDO: 1.82, Pf3D7: 1.65; SI > 109 (HEK/PfINDO) & 121 (HEK/Pf3D7)] obtained from previous studies. The SFs were tested against Plasmodium falciparum 3D7 (Pf3D7-chloroquine sensitive) and INDO (PfINDO-chloroquine resistant) strains in culture. Also, the phytochemical profile of potent SFs was determined and finally, the inhibition of the asexual blood stages of Plasmodium falciparum by the SFs with the highest promise was assessed. MATERIAL AND METHODS Selected SFs were submitted to a second bio-guided fractionation using silica gel column chromatography. The partial phytochemical composition of potent antiplasmodial SFs was determined using gas chromatography coupled to mass spectrometry (GC-MS). The SYBR Green I-based fluorescence microtiter plate assay was used to monitor the growth of Plasmodium falciparum parasites in culture in the presence or absence of extracts. Microscopy and flow cytometry counting was used to assess the Plasmodium falciparum stage-specific inhibition and post-drug exposure growth suppression by highly potent extracts. RESULTS Twenty-one of the 39 SFs afforded from TmsbwChl showed activity (IC50: 0.29-4.74 μg/mL) against both Pf3D7 and PfINDO strains. Of note, eight SFs namely, Tm25, Tm28-30, Tm34-36 and Tm38, exerted highly potent antiplasmodial activity (IC50 < 1 μg/mL) with IC50PfINDO: 0.41-0.84 μg/mL and IC50Pf3D7: 0.29-0.68 μg/mL. They also displayed very high selectivity (50 < SIPfINDO, SIPf3D7 > 344) on the two Plasmodial strains. On the other hand, 7 SFs (SFs Ts03, Ts04, Ts06, Ts09, Ts10, Ts12 and Ts13) from TsrmEA showed promising inhibitory potential against both parasite strains (IC50: 2.01-5.14 μg/mL). Sub fraction Tm36 (IC50PfINDO: 0.41 μg/mL, SIPfINDO > 243; IC50Pf3D7: 0.29 μg/mL, SIPf3D7 > 344) showed the highest promise. The GC-MS analysis of the 8 selected SFs led to the identification of 99 phytometabolites, with D-limonene (2), benzaldehyde (12), carvone (13), caryophyllene (35), hexadecanoic acid, methyl ester (74) and 9-octadecenoic acid, methyl ester (82) being the main constituents. Sub fractions Tm28, Tm29, Tm30, Tm36 and Tm38 inhibited all the three intraerythrocytic stages of P. falciparum, with strong potency against ring stage development, merozoite egress and invasion processes. CONCLUSIONS This study has identified highly potent antiplasmodial SFs from Terminalia mantaly with significant activity on the intraerythrocytic development of Plasmodium falciparum. These SFs qualify as promising sources of novel antiplasmodial lead compounds. Further purification and characterization studies are expected to unravel molecular targets in rings and merozoites.
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Affiliation(s)
- Cedric Derick Jiatsa Mbouna
- Antimicrobial and Biocontrol Agents Unit, Laboratory for Phytobiochemistry and Medicinal Plants Study, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
| | - Brice Mariscal Tchatat Tali
- Antimicrobial and Biocontrol Agents Unit, Laboratory for Phytobiochemistry and Medicinal Plants Study, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
| | - Patrick Valere Tsouh Fokou
- Antimicrobial and Biocontrol Agents Unit, Laboratory for Phytobiochemistry and Medicinal Plants Study, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon; Department of Biochemistry, Faculty of Sciences, University of Bamenda, PO Box 39, Bambili, Cameroon
| | - Eugenie Aimee Madiesse Kemgne
- Antimicrobial and Biocontrol Agents Unit, Laboratory for Phytobiochemistry and Medicinal Plants Study, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
| | - Rodrigue Keumoe
- Antimicrobial and Biocontrol Agents Unit, Laboratory for Phytobiochemistry and Medicinal Plants Study, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
| | - Rufin Marie Toghueo Kouipou
- Antimicrobial and Biocontrol Agents Unit, Laboratory for Phytobiochemistry and Medicinal Plants Study, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon
| | - Lauve Rachel Yamthe Tchokouaha
- Antimicrobial and Biocontrol Agents Unit, Laboratory for Phytobiochemistry and Medicinal Plants Study, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon; Institute for Medical Research and Medicinal Plants Studies (IMPM), Yaoundé, P.O. Box 6163, Yaoundé, Cameroon
| | - Marthe Aimée Tchuente Tchuenmogne
- Laboratory of Natural Products and Organic Synthesis, Department of Organic Chemistry,Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon
| | - Donald Kagho Kenou
- Laboratory of Natural Products and Organic Synthesis, Department of Organic Chemistry,Faculty of Science, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon
| | - Dinkar Sahal
- Malaria Drug Discovery Laboratory, International Centre for Genetic Engineering and Biotechnology, New Delhi -110067, India.
| | - Fabrice Fekam Boyom
- Antimicrobial and Biocontrol Agents Unit, Laboratory for Phytobiochemistry and Medicinal Plants Study, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaoundé, Cameroon.
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Schlott AC, Knuepfer E, Green JL, Hobson P, Borg AJ, Morales-Sanfrutos J, Perrin AJ, Maclachlan C, Collinson LM, Snijders AP, Tate EW, Holder AA. Inhibition of protein N-myristoylation blocks Plasmodium falciparum intraerythrocytic development, egress and invasion. PLoS Biol 2021; 19:e3001408. [PMID: 34695132 PMCID: PMC8544853 DOI: 10.1371/journal.pbio.3001408] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 09/07/2021] [Indexed: 11/29/2022] Open
Abstract
We have combined chemical biology and genetic modification approaches to investigate the importance of protein myristoylation in the human malaria parasite, Plasmodium falciparum. Parasite treatment during schizogony in the last 10 to 15 hours of the erythrocytic cycle with IMP-1002, an inhibitor of N-myristoyl transferase (NMT), led to a significant blockade in parasite egress from the infected erythrocyte. Two rhoptry proteins were mislocalized in the cell, suggesting that rhoptry function is disrupted. We identified 16 NMT substrates for which myristoylation was significantly reduced by NMT inhibitor (NMTi) treatment, and, of these, 6 proteins were substantially reduced in abundance. In a viability screen, we showed that for 4 of these proteins replacement of the N-terminal glycine with alanine to prevent myristoylation had a substantial effect on parasite fitness. In detailed studies of one NMT substrate, glideosome-associated protein 45 (GAP45), loss of myristoylation had no impact on protein location or glideosome assembly, in contrast to the disruption caused by GAP45 gene deletion, but GAP45 myristoylation was essential for erythrocyte invasion. Therefore, there are at least 3 mechanisms by which inhibition of NMT can disrupt parasite development and growth: early in parasite development, leading to the inhibition of schizogony and formation of “pseudoschizonts,” which has been described previously; at the end of schizogony, with disruption of rhoptry formation, merozoite development and egress from the infected erythrocyte; and at invasion, when impairment of motor complex function prevents invasion of new erythrocytes. These results underline the importance of P. falciparum NMT as a drug target because of the pleiotropic effect of its inhibition. Understanding the essential factors needed for malaria parasite development could help us find new therapeutic targets. This study reveals that N-myristoylation is a posttranslational modification of proteins essential for the parasites’ growth and their invasion of red blood cells.
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Affiliation(s)
- Anja C. Schlott
- Malaria Parasitology Laboratory, Francis Crick Institute, London, United Kingdom
- Molecular Sciences Research Hub, Imperial College, London, United Kingdom
| | - Ellen Knuepfer
- Malaria Parasitology Laboratory, Francis Crick Institute, London, United Kingdom
- Department of Pathobiology and Population Sciences, The Royal Veterinary College, Hatfield, United Kingdom
| | - Judith L. Green
- Malaria Parasitology Laboratory, Francis Crick Institute, London, United Kingdom
| | - Philip Hobson
- Flow Cytometry Science Technology Platform, Francis Crick Institute, London, United Kingdom
| | - Aaron J. Borg
- Mass Spectrometry Proteomics Science Technology Platform, Francis Crick Institute, London, United Kingdom
| | | | - Abigail J. Perrin
- Malaria Biochemistry Laboratory, Francis Crick Institute, London, United Kingdom
| | - Catherine Maclachlan
- Electron Microscopy Science Technology Platform, Francis Crick Institute, London, United Kingdom
| | - Lucy M. Collinson
- Electron Microscopy Science Technology Platform, Francis Crick Institute, London, United Kingdom
| | - Ambrosius P. Snijders
- Mass Spectrometry Proteomics Science Technology Platform, Francis Crick Institute, London, United Kingdom
| | - Edward W. Tate
- Molecular Sciences Research Hub, Imperial College, London, United Kingdom
- Francis Crick Institute, London, United Kingdom
- * E-mail: (EWT); (AAH)
| | - Anthony A. Holder
- Malaria Parasitology Laboratory, Francis Crick Institute, London, United Kingdom
- * E-mail: (EWT); (AAH)
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Wang X, Xie Y, Jiang N, Wang J, Liang H, Liu D, Yang N, Sang X, Feng Y, Chen R, Chen Q. Enhanced Antimalarial Efficacy Obtained by Targeted Delivery of Artemisinin in Heparin-Coated Magnetic Hollow Mesoporous Nanoparticles. ACS Appl Mater Interfaces 2021; 13:287-297. [PMID: 33356111 DOI: 10.1021/acsami.0c20070] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Malaria is one of the deadliest infectious diseases threatening half of the world population. With the deterioration of the parasiticidal effect of the current antimalarials, novel approaches such as screening of more specific inhibitors and targeted delivery of drugs have been under intensive research. Herein, we prepare hollow mesoporous ferrite nanoparticles (HMFNs) of 200 nm with ferromagnetic properties using a one-pot hydrothermal reaction. A magnetically targeted drug-delivery system coloaded with artemisinin in the inner magnetite shell and heparin on the outer mesoporous shell (HMFN@ART@HEP) is developed. Specific targeting of the magnetic nanoparticles to the parasite-infected erythrocytes is achieved by the attraction between the HMFNs and hemozoin (paramagnetic), a vital metabolite of plasmodium in the erythrocytic stage. With the hemozoin production reaching the maximum during the schizont period of the parasite, HMFN@ART@HEPs are adsorbed to the infected red blood cells (iRBCs), which not only interferes with the release of merozoites but also significantly enhances the inhibitory efficacy due to the increased local concentration of artemisinin. Subsequently, the heparin coated on the surface of the nanoparticles can efficiently interfere with the invasion of freshly released merozoites to new RBCs through the specific interaction between the parasite-derived ligands and heparin, which further increases the inhibitory effect on malaria. As a cluster of heparin, heparin-coated nanoparticles provide stronger blocking capability than free heparin, resulting from multivalent interactions with surface receptors on merozoite. Thus, we have developed a HMFN-based delivery system with considerable antimalarial efficacy, which is a promising platform for treatment against malaria.
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Affiliation(s)
- Xinyi Wang
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China
- The Research Unit for Pathogenic Mechanisms of Zoonotic Parasites, Chinese Academy of Medical Sciences, 120 Dongling Road, Shenyang 110866, China
- College of Basic Sciences, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China
| | - Yiwei Xie
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China
- The Research Unit for Pathogenic Mechanisms of Zoonotic Parasites, Chinese Academy of Medical Sciences, 120 Dongling Road, Shenyang 110866, China
| | - Ning Jiang
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China
- The Research Unit for Pathogenic Mechanisms of Zoonotic Parasites, Chinese Academy of Medical Sciences, 120 Dongling Road, Shenyang 110866, China
| | - Jingyi Wang
- College of Information and Electrical Engineering, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China
| | - Hongrui Liang
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China
- The Research Unit for Pathogenic Mechanisms of Zoonotic Parasites, Chinese Academy of Medical Sciences, 120 Dongling Road, Shenyang 110866, China
| | - Dingyuan Liu
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China
- The Research Unit for Pathogenic Mechanisms of Zoonotic Parasites, Chinese Academy of Medical Sciences, 120 Dongling Road, Shenyang 110866, China
| | - Na Yang
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China
- The Research Unit for Pathogenic Mechanisms of Zoonotic Parasites, Chinese Academy of Medical Sciences, 120 Dongling Road, Shenyang 110866, China
| | - Xiaoyu Sang
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China
- The Research Unit for Pathogenic Mechanisms of Zoonotic Parasites, Chinese Academy of Medical Sciences, 120 Dongling Road, Shenyang 110866, China
| | - Ying Feng
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China
- The Research Unit for Pathogenic Mechanisms of Zoonotic Parasites, Chinese Academy of Medical Sciences, 120 Dongling Road, Shenyang 110866, China
| | - Ran Chen
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China
- The Research Unit for Pathogenic Mechanisms of Zoonotic Parasites, Chinese Academy of Medical Sciences, 120 Dongling Road, Shenyang 110866, China
| | - Qijun Chen
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China
- The Research Unit for Pathogenic Mechanisms of Zoonotic Parasites, Chinese Academy of Medical Sciences, 120 Dongling Road, Shenyang 110866, China
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Stoute JA, Landmesser ME, Biryukov S. Treatment of Plasmodium falciparum merozoites with the protease inhibitor E64 and mechanical filtration increases their susceptibility to complement activation. PLoS One 2020; 15:e0237786. [PMID: 32822376 PMCID: PMC7442247 DOI: 10.1371/journal.pone.0237786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 06/22/2020] [Indexed: 11/18/2022] Open
Abstract
Plasmodium falciparum malaria killed 451,000 people in 2017. Merozoites, the stage of the parasite that invades RBCs, are a logical target for vaccine development. Treatment with the protease inhibitor E64 followed by filtration through a 1.2 μm filter is being used to purify merozoites for immunologic assays. However, there have been no studies to determine the effect of these treatments on the susceptibility of merozoites to complement or antibodies. To address this gap, we purified merozoites with or without E64 followed by filtration through either a 1.2 or 2.7 μm filter, or no filtration. Merozoites were then incubated in either 10% fresh or heat-inactivated serum followed by surface staining and flow cytometry with monoclonal antibodies against the complement effector molecules C3b or C5b9. To determine the effect of anti-merozoite antibodies, we incubated merozoites with MAb5.2, a mouse monoclonal antibody that targets the merozoite surface protein 1. We used an amine-reactive fluorescent dye to measure membrane integrity. Treatment with E64 resulted in an insignificant increase in the proportion of merozoites that were C3b positive but in a significant increase in the proportion that were C5b9 positive. Filtration increased the proportion of merozoites that were either C3b or C5b9-positive. The combination of filtration and E64 treatment resulted in marked deposition of C3b and C5b9. MAb5.2 induced greater complement deposition than serum alone or an IgG2b isotype control. The combination of E64 treatment, filtration, and MAb5.2 resulted in very rapid and significant deposition of C5b9. Filtration through the 1.2 μm filter selected a population of merozoites with greater membrane integrity, but their integrity deteriorated rapidly upon exposure to serum. We conclude that E64 treatment and filtration increase the susceptibility of merozoites to complement and antibody. Filtered or E64-treated merozoites are not suitable for immunologic studies that address the efficacy of antibodies in vitro.
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Affiliation(s)
- José A. Stoute
- The Division of Infectious Diseases, Department of Medicine, the Penn State College of Medicine, Hershey, Pennsylvania, United States of America
- Department of Microbiology and Immunology, The Penn State College of Medicine, Hershey, Pennsylvania, United States of America
- * E-mail: ,
| | - Mary E. Landmesser
- The Division of Infectious Diseases, Department of Medicine, the Penn State College of Medicine, Hershey, Pennsylvania, United States of America
| | - Sergei Biryukov
- Department of Microbiology and Immunology, The Penn State College of Medicine, Hershey, Pennsylvania, United States of America
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Favuzza P, de Lera Ruiz M, Thompson JK, Triglia T, Ngo A, Steel RWJ, Vavrek M, Christensen J, Healer J, Boyce C, Guo Z, Hu M, Khan T, Murgolo N, Zhao L, Penington JS, Reaksudsan K, Jarman K, Dietrich MH, Richardson L, Guo KY, Lopaticki S, Tham WH, Rottmann M, Papenfuss T, Robbins JA, Boddey JA, Sleebs BE, Sabroux HJ, McCauley JA, Olsen DB, Cowman AF. Dual Plasmepsin-Targeting Antimalarial Agents Disrupt Multiple Stages of the Malaria Parasite Life Cycle. Cell Host Microbe 2020; 27:642-658.e12. [PMID: 32109369 PMCID: PMC7146544 DOI: 10.1016/j.chom.2020.02.005] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 12/22/2019] [Accepted: 02/11/2020] [Indexed: 01/07/2023]
Abstract
Artemisin combination therapy (ACT) is the main treatment option for malaria, which is caused by the intracellular parasite Plasmodium. However, increased resistance to ACT highlights the importance of finding new drugs. Recently, the aspartic proteases Plasmepsin IX and X (PMIX and PMX) were identified as promising drug targets. In this study, we describe dual inhibitors of PMIX and PMX, including WM382, that block multiple stages of the Plasmodium life cycle. We demonstrate that PMX is a master modulator of merozoite invasion and direct maturation of proteins required for invasion, parasite development, and egress. Oral administration of WM382 cured mice of P. berghei and prevented blood infection from the liver. In addition, WM382 was efficacious against P. falciparum asexual infection in humanized mice and prevented transmission to mosquitoes. Selection of resistant P. falciparum in vitro was not achievable. Together, these show that dual PMIX and PMX inhibitors are promising candidates for malaria treatment and prevention.
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Affiliation(s)
- Paola Favuzza
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | | | - Jennifer K Thompson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Tony Triglia
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Anna Ngo
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Ryan W J Steel
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Marissa Vavrek
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA
| | - Janni Christensen
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Julie Healer
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | | | - Zhuyan Guo
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA
| | - Mengwei Hu
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA
| | - Tanweer Khan
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA
| | - Nicholas Murgolo
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA
| | - Lianyun Zhao
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA
| | | | - Kitsanapong Reaksudsan
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Kate Jarman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Melanie H Dietrich
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Lachlan Richardson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Kai-Yuan Guo
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Sash Lopaticki
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Wai-Hong Tham
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | | | - Tony Papenfuss
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | | | - Justin A Boddey
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - Hélène Jousset Sabroux
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia
| | - John A McCauley
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA
| | - David B Olsen
- Merck & Co., Inc., 770 Sumneytown Pike, West Point, PA 19486, USA.
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; University of Melbourne, Melbourne, VIC 3010, Australia.
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Healer J, Wong W, Thompson JK, He W, Birkinshaw RW, Miura K, Long CA, Soroka V, Søgaard TMM, Jørgensen T, de Jongh WA, Weir C, Svahn E, Czabotar PE, Tham W, Mueller I, Barlow PN, Cowman AF. Neutralising antibodies block the function of Rh5/Ripr/CyRPA complex during invasion of Plasmodium falciparum into human erythrocytes. Cell Microbiol 2019; 21:e13030. [PMID: 30965383 PMCID: PMC6594224 DOI: 10.1111/cmi.13030] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 03/04/2019] [Accepted: 03/11/2019] [Indexed: 01/19/2023]
Abstract
An effective vaccine is a priority for malaria control and elimination. The leading candidate in the Plasmodium falciparum blood stage is PfRh5. PfRh5 assembles into trimeric complex with PfRipr and PfCyRPA in the parasite, and this complex is essential for erythrocyte invasion. In this study, we show that antibodies specific for PfRh5 and PfCyRPA prevent trimeric complex formation. We identify the EGF-7 domain on PfRipr as a neutralising epitope and demonstrate that antibodies against this region act downstream of complex formation to prevent merozoite invasion. Antibodies against the C-terminal region of PfRipr were more inhibitory than those against either PfRh5 or PfCyRPA alone, and a combination of antibodies against PfCyRPA and PfRipr acted synergistically to reduce invasion. This study supports prioritisation of PfRipr for development as part of a next-generation antimalarial vaccine.
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Affiliation(s)
- Julie Healer
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Wilson Wong
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Jennifer K. Thompson
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
| | - Wengqiang He
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Richard W. Birkinshaw
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector ResearchNational Institute of Allergy and Infectious Diseases, National Institutes of HealthBethesdaMarylandUSA
| | - Carol A. Long
- Laboratory of Malaria and Vector ResearchNational Institute of Allergy and Infectious Diseases, National Institutes of HealthBethesdaMarylandUSA
| | | | | | | | | | - Christopher Weir
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
- Schools of Chemistry and Biological SciencesUniversity of EdinburghEdinburghScotland, UK
| | - Ella Svahn
- Schools of Chemistry and Biological SciencesUniversity of EdinburghEdinburghScotland, UK
| | - Peter E. Czabotar
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Wai‐Hong Tham
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Ivo Mueller
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
| | - Paul N. Barlow
- Schools of Chemistry and Biological SciencesUniversity of EdinburghEdinburghScotland, UK
| | - Alan F. Cowman
- Infection and ImmunityWalter and Eliza Hall Institute of Medical ResearchMelbourneVictoriaAustralia
- Department of Medical BiologyUniversity of MelbourneMelbourneVictoriaAustralia
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7
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Tohmoto T, Takashima E, Takeo S, Morita M, Nagaoka H, Udomsangpetch R, Sattabongkot J, Ishino T, Torii M, Tsuboi T. Anti-MSP11 IgG inhibits Plasmodium falciparum merozoite invasion into erythrocytes in vitro. Parasitol Int 2018; 69:25-29. [PMID: 30385417 DOI: 10.1016/j.parint.2018.10.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/18/2018] [Accepted: 10/29/2018] [Indexed: 11/19/2022]
Abstract
Merozoite surface proteins (MSPs) are considered as promising blood-stage malaria vaccine candidates. MSP3 has long been evaluated for its vaccine candidacy, however, the candidacy of other members of MSP3 family is insufficiently characterized. Here, we investigated Plasmodium falciparum MSP11 (PF3D7_1036000), a member of the MSP3 family, for its potential as a blood-stage vaccine candidate. The full-length protein (MSP11-FL) as well as the N-terminal half-MSP11 (MSP11-N), known to be unique among the MSP3 family members, were expressed by wheat germ cell-free system, and used to raise antibodies in rabbit. Immunoblot analysis of schizont lysates probed with anti-MSP11-N antibodies detected double bands at approximately 40 and 60 kDa, consistent with the previous report thus confirming antibodies specificity. However, inconsistent with previously reported merozoite's surface localization, immunofluorescence assay (IFA) revealed that MSP11 likely localizes to rhoptry neck of merozoites in mature schizonts. After invasion, MSP11 localized to parasitophorous vacuole and thereafter in Maurer's clefts in trophozoites. Anti-MSP11-FL antibody levels were significantly higher in asymptomatic than symptomatic P. falciparum cases in malaria low endemic Thailand. This reconfirmed that anti-MSP11 antibodies play an important role in protection against clinical malaria, as previously reported. Furthermore, in vitro growth inhibition assay revealed that anti-MSP11-FL rabbit antibodies biologically function by inhibiting merozoite invasion of erythrocytes. These findings further support the vaccine candidacy of MSP11.
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Affiliation(s)
- Tatsuhiro Tohmoto
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Eizo Takashima
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan.
| | - Satoru Takeo
- Division of Tropical Diseases and Parasitology, Department of Infectious Diseases, Faculty of Medicine, Kyorin University, Mitaka, Tokyo 181-8611, Japan
| | - Masayuki Morita
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Hikaru Nagaoka
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Rachanee Udomsangpetch
- Center for Research and Innovation, Faculty of Medical Technology, Mahidol University, Salaya, Nakhosn Pathom 73170, Thailand
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Tomoko Ishino
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime 791-0295, Japan
| | - Motomi Torii
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime 791-0295, Japan
| | - Takafumi Tsuboi
- Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan.
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8
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Leitgeb AM, Charunwatthana P, Rueangveerayut R, Uthaisin C, Silamut K, Chotivanich K, Sila P, Moll K, Lee SJ, Lindgren M, Holmer E, Färnert A, Kiwuwa MS, Kristensen J, Herder C, Tarning J, Wahlgren M, Dondorp AM. Inhibition of merozoite invasion and transient de-sequestration by sevuparin in humans with Plasmodium falciparum malaria. PLoS One 2017; 12:e0188754. [PMID: 29244851 PMCID: PMC5731734 DOI: 10.1371/journal.pone.0188754] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 11/03/2017] [Indexed: 11/19/2022] Open
Abstract
SEVERE MALARIA Even with the best available treatment, the mortality from severe Plasmodium falciparum malaria remains high. Typical features at death are high parasite loads and obstructed micro- vasculature. Infected erythrocytes (IE) containing mature parasites bind to the host receptor heparan sulfate, which is also an important receptor for merozoite invasion. To block merozoite invasion has not previously been proposed as an adjunctive therapeutic approach but it may preclude the early expansion of an infection that else leads to exacerbated sequestration and death. SEVUPARIN IN PHASE I STUDY The drug sevuparin was developed from heparin because heparan sulfate and heparin are nearly identical, so the rationale was that sevuparin would act as a decoy receptor during malaria infection. A phase I study was performed in healthy male volunteers and sevuparin was found safe and well tolerated. SEVUPARIN IN PHASE I/II CLINICAL STUDY A phase I/II clinical study was performed in which sevuparin was administered via short intravenous infusions to malaria patients with uncomplicated malaria who were also receiving atovaquone/proguanil treatment. This was a Phase I/II, randomized, open label, active control, parallel assignment study. Sevuparin was safe and well tolerated in the malaria patients. The mean relative numbers of ring-stage IEs decreased after a single sevuparin infusion and mature parasite IEs appeared transiently in the circulation. The effects observed on numbers of merozoites and throphozoites in the circulation, were detected already one hour after the first sevuparin injection. Here we report the development of a candidate drug named sevuparin that both blocks merozoite invasion and transiently de-sequesters IE in humans with P. falciparum malaria. TRIAL REGISTRATION ClinicalTrials.gov NCT01442168.
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Affiliation(s)
| | | | | | | | - Kamolrat Silamut
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | | | - Kirsten Moll
- Department of Microbiology, Tumor- and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Sue J. Lee
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | | | | | - Anna Färnert
- Department of Infectious Diseases, Karolinska University Hospital and Department Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Mpungu S. Kiwuwa
- Department of Pediatrics, School of Medicine, Makerere University College of Health Sciences, and Department of Biochemistry, School of Biomedical Sciences, Makerere University College of Health Sciences, Kampala, Uganda
| | | | | | - Joel Tarning
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mats Wahlgren
- Department of Microbiology, Tumor- and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Arjen M. Dondorp
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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9
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Bianchin A, Bell A, Chubb AJ, Doolan N, Leneghan D, Stavropoulos I, Shields DC, Mooney C. Design and evaluation of antimalarial peptides derived from prediction of short linear motifs in proteins related to erythrocyte invasion. PLoS One 2015; 10:e0127383. [PMID: 26039561 PMCID: PMC4454681 DOI: 10.1371/journal.pone.0127383] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 04/15/2015] [Indexed: 11/19/2022] Open
Abstract
The purpose of this study was to investigate the blood stage of the malaria causing parasite, Plasmodium falciparum, to predict potential protein interactions between the parasite merozoite and the host erythrocyte and design peptides that could interrupt these predicted interactions. We screened the P. falciparum and human proteomes for computationally predicted short linear motifs (SLiMs) in cytoplasmic portions of transmembrane proteins that could play roles in the invasion of the erythrocyte by the merozoite, an essential step in malarial pathogenesis. We tested thirteen peptides predicted to contain SLiMs, twelve of them palmitoylated to enhance membrane targeting, and found three that blocked parasite growth in culture by inhibiting the initiation of new infections in erythrocytes. Scrambled peptides for two of the most promising peptides suggested that their activity may be reflective of amino acid properties, in particular, positive charge. However, one peptide showed effects which were stronger than those of scrambled peptides. This was derived from human red blood cell glycophorin-B. We concluded that proteome-wide computational screening of the intracellular regions of both host and pathogen adhesion proteins provides potential lead peptides for the development of anti-malarial compounds.
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Affiliation(s)
- Alessandra Bianchin
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
- Complex and Adaptive Systems Laboratory, University College Dublin, Dublin, Ireland
- School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
| | - Angus Bell
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
| | - Anthony J. Chubb
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
- Complex and Adaptive Systems Laboratory, University College Dublin, Dublin, Ireland
- School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Nathalie Doolan
- School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Darren Leneghan
- Department of Microbiology, School of Genetics and Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, Ireland
| | - Ilias Stavropoulos
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
- Complex and Adaptive Systems Laboratory, University College Dublin, Dublin, Ireland
- School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Denis C. Shields
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
- Complex and Adaptive Systems Laboratory, University College Dublin, Dublin, Ireland
- School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Catherine Mooney
- Conway Institute of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
- Complex and Adaptive Systems Laboratory, University College Dublin, Dublin, Ireland
- School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
- * E-mail:
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10
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Itani S, Torii M, Ishino T. D-Glucose concentration is the key factor facilitating liver stage maturation of Plasmodium. Parasitol Int 2014; 63:584-90. [PMID: 24691399 DOI: 10.1016/j.parint.2014.03.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 02/14/2014] [Accepted: 03/21/2014] [Indexed: 12/31/2022]
Abstract
The course of malaria infection in mammals begins with transmission of Plasmodium sporozoites into the skin by Anopheles mosquitoes, followed by migration of the sporozoites to the liver. As no symptoms present until hepatic merozoites are released and until they infect erythrocytes in the blood vessels, sporozoites and liver-stage (LS) parasites are promising targets for anti-malaria drugs aiming to prevent mosquito-to-mammal transmission. In vitro LS parasite development system is useful in the screening of candidate drugs on LS parasite development and the elucidation of its underlying molecular mechanisms, which remain unclear. Using rodent malaria parasites (Plasmodium berghei) as a model, this study aimed to develop an optimal in vitro LS culture system for the full maturation of the LS parasite into the hepatic merozoite, the next infective stage in parasite development. As the development of this system required measurement of maturation, a novel quantitative index of LS parasite maturation based on the expression pattern of liver-specific protein 2 (LISP2) was first developed. The use of this index for comparing the effect of incubation in different culture media on LS maturation revealed that the d-glucose concentration of the culture medium is the key factor promoting parasite development in hepatocytes and that a d-glucose concentration of 2000mg/L/day is the threshold concentration at which the maturation of P. berghei into infective hepatic merozoites is achieved. These findings can be utilized to optimize a human malaria LS culture system for drug discovery.
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Affiliation(s)
- Satoko Itani
- Department of Molecular Parasitology, Graduate School of Medicine, Ehime University, Shitsukawa, Toon, Ehime 791-0295, Japan
| | - Motomi Torii
- Department of Molecular Parasitology, Graduate School of Medicine, Ehime University, Shitsukawa, Toon, Ehime 791-0295, Japan; Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime 791-0295, Japan
| | - Tomoko Ishino
- Department of Molecular Parasitology, Graduate School of Medicine, Ehime University, Shitsukawa, Toon, Ehime 791-0295, Japan; Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Shitsukawa, Toon, Ehime 791-0295, Japan.
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11
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Hans N, Singh S, Pandey AK, Reddy KS, Gaur D, Chauhan VS. Identification and characterization of a novel Plasmodium falciparum adhesin involved in erythrocyte invasion. PLoS One 2013; 8:e74790. [PMID: 24058628 PMCID: PMC3772933 DOI: 10.1371/journal.pone.0074790] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 08/05/2013] [Indexed: 11/18/2022] Open
Abstract
Malaria remains a major health problem worldwide. All clinical symptoms of malaria are attributed to the asexual blood stages of the parasite life cycle. Proteins resident in apical organelles and present on the surface of P. falciparum merozoites are considered promising candidates for the development of blood stage malaria vaccines. In the present study, we have identified and characterized a microneme associated antigen, PfMA [PlasmoDB Gene ID: PF3D7_0316000, PFC0700c]. The gene was selected by applying a set of screening criteria such as transcriptional upregulation at late schizogony, inter-species conservation and the presence of signal sequence or transmembrane domains. The gene sequence of PfMA was found to be conserved amongst various Plasmodium species. We experimentally demonstrated that the transcript for PfMA was expressed only in the late blood stages of parasite consistent with a putative role in erythrocyte invasion. PfMA was localized by immunofluorescence and immuno-electron microscopy to be in the micronemes, an apical organelle of merozoites. The functional role of the PfMA protein in erythrocyte invasion was identified as a parasite adhesin involved in direct attachment with the target erythrocyte. PfMA was demonstrated to bind erythrocytes in a sialic acid independent, chymotrypsin and trypsin resistant manner and its antibodies inhibited P. falciparum erythrocyte invasion. Invasion of erythrocytes is a complex multistep process that involves a number of redundant ligand-receptor interactions many of which still remain unknown and even uncharacterized. Our work has identified and characterized a novel P. falciparum adhesin involved in erythrocyte invasion.
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Affiliation(s)
- Nidhi Hans
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Shailja Singh
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Alok K. Pandey
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - K. Sony Reddy
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Deepak Gaur
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Virander S. Chauhan
- Malaria Research Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
- * E-mail:
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12
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Bouillon A, Giganti D, Benedet C, Gorgette O, Pêtres S, Crublet E, Girard-Blanc C, Witkowski B, Ménard D, Nilges M, Mercereau-Puijalon O, Stoven V, Barale JC. In Silico screening on the three-dimensional model of the Plasmodium vivax SUB1 protease leads to the validation of a novel anti-parasite compound. J Biol Chem 2013; 288:18561-73. [PMID: 23653352 PMCID: PMC3689996 DOI: 10.1074/jbc.m113.456764] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 04/03/2013] [Indexed: 12/12/2022] Open
Abstract
Widespread drug resistance calls for the urgent development of new antimalarials that target novel steps in the life cycle of Plasmodium falciparum and Plasmodium vivax. The essential subtilisin-like serine protease SUB1 of Plasmodium merozoites plays a dual role in egress from and invasion into host erythrocytes. It belongs to a new generation of attractive drug targets against which specific potent inhibitors are actively searched. We characterize here the P. vivax SUB1 enzyme and show that it displays a typical auto-processing pattern and apical localization in P. vivax merozoites. To search for small PvSUB1 inhibitors, we took advantage of the similarity of SUB1 with bacterial subtilisins and generated P. vivax SUB1 three-dimensional models. The structure-based virtual screening of a large commercial chemical compounds library identified 306 virtual best hits, of which 37 were experimentally confirmed inhibitors and 5 had Ki values of <50 μM for PvSUB1. Interestingly, they belong to different chemical families. The most promising competitive inhibitor of PvSUB1 (compound 2) was equally active on PfSUB1 and displayed anti-P. falciparum and Plasmodium berghei activity in vitro and in vivo, respectively. Compound 2 inhibited the endogenous PfSUB1 as illustrated by the inhibited maturation of its natural substrate PfSERA5 and inhibited parasite egress and subsequent erythrocyte invasion. These data indicate that the strategy of in silico screening of three-dimensional models to select for virtual inhibitors combined with stringent biological validation successfully identified several inhibitors of the PvSUB1 enzyme. The most promising hit proved to be a potent cross-inhibitor of PlasmodiumSUB1, laying the groundwork for the development of a globally active small compound antimalarial.
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Affiliation(s)
- Anthony Bouillon
- From the Institut Pasteur, Unité d'Immunologie Moléculaire des Parasites, Département de Parasitologie et de Mycologie, F-75015 Paris, France
- CNRS, URA2581, F-75015 Paris, France
| | - David Giganti
- the Institut Pasteur, Unité de Bioinformatique Structurale, Département de Biologie Structurale et Chimie, F-75015 Paris, France
- CNRS, UMR3258, F-75015 Paris, France
| | - Christophe Benedet
- the Pasteur Institute of Cambodia, Malaria Molecular Epidemiology Unit, Phnom Penh, Cambodia
| | - Olivier Gorgette
- From the Institut Pasteur, Unité d'Immunologie Moléculaire des Parasites, Département de Parasitologie et de Mycologie, F-75015 Paris, France
- CNRS, URA2581, F-75015 Paris, France
| | - Stéphane Pêtres
- the Institut Pasteur, Proteopole, Département de Biologie Structurale et Chimie, F-75015 Paris, France
| | - Elodie Crublet
- the Institut Pasteur, Proteopole, Département de Biologie Structurale et Chimie, F-75015 Paris, France
| | - Christine Girard-Blanc
- the Institut Pasteur, Proteopole, Département de Biologie Structurale et Chimie, F-75015 Paris, France
| | - Benoit Witkowski
- the Pasteur Institute of Cambodia, Malaria Molecular Epidemiology Unit, Phnom Penh, Cambodia
| | - Didier Ménard
- the Pasteur Institute of Cambodia, Malaria Molecular Epidemiology Unit, Phnom Penh, Cambodia
| | - Michael Nilges
- the Institut Pasteur, Unité de Bioinformatique Structurale, Département de Biologie Structurale et Chimie, F-75015 Paris, France
- CNRS, UMR3258, F-75015 Paris, France
| | - Odile Mercereau-Puijalon
- From the Institut Pasteur, Unité d'Immunologie Moléculaire des Parasites, Département de Parasitologie et de Mycologie, F-75015 Paris, France
- CNRS, URA2581, F-75015 Paris, France
| | - Véronique Stoven
- the Center for Computational Biology, Mines-ParisTech, Fontainebleau F-77300 France, and
- the Institut Curie, INSERM U900, F-75248 Paris, France
| | - Jean-Christophe Barale
- From the Institut Pasteur, Unité d'Immunologie Moléculaire des Parasites, Département de Parasitologie et de Mycologie, F-75015 Paris, France
- CNRS, URA2581, F-75015 Paris, France
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13
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Tulone C, Sponaas AM, Raiber EA, Tabor AB, Langhorne J, Chain BM. Differential requirement for cathepsin D for processing of the full length and C-terminal fragment of the malaria antigen MSP1. PLoS One 2011; 6:e24886. [PMID: 22053177 PMCID: PMC3203867 DOI: 10.1371/journal.pone.0024886] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 08/23/2011] [Indexed: 11/19/2022] Open
Abstract
Merozoite Surface Protein 1 is expressed on the surface of malaria merozoites and is important for invasion of the malaria parasite into erythrocytes. MSP1-specific CD4 T cell responses and antibody can confer protective immunity in experimental models of malaria. In this study we explore the contributions of cathepsins D and E, two aspartic proteinases previously implicated in antigen processing, to generating MSP1 CD4 T-cell epitopes for presentation. The absence of cathepsin D, a late endosome/lysosomal enzyme, is associated with a reduced presentation of MSP1 both following in vitro processing of the epitope MSP1 from infected erythrocytes by bone marrow-derived dendritic cells, and following in vivo processing by splenic CD11c+ dendritic cells. By contrast, processing and presentation of the soluble recombinant protein fragment of MSP1 is unaffected by the absence of cathepsin D, but is inhibited when both cathepsin D and E are absent. The role of different proteinases in generating the CD4 T cell repertoire, therefore, depends on the context in which an antigen is introduced to the immune system.
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Affiliation(s)
- Calogero Tulone
- Division of Infection and Immunity, University College London, London, United Kingdom
| | - Anne-Marit Sponaas
- Division of Parasitology MRC National Institute of Medical Research, London, United Kingdom
| | - Eun-Ang Raiber
- Department of Chemistry, University College London, London, United Kingdom
| | - Alethea B. Tabor
- Department of Chemistry, University College London, London, United Kingdom
| | - Jean Langhorne
- Division of Parasitology MRC National Institute of Medical Research, London, United Kingdom
| | - Benny M. Chain
- Division of Infection and Immunity, University College London, London, United Kingdom
- * E-mail:
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14
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Bastianelli G, Bouillon A, Nguyen C, Crublet E, Pêtres S, Gorgette O, Le-Nguyen D, Barale JC, Nilges M. Computational reverse-engineering of a spider-venom derived peptide active against Plasmodium falciparum SUB1. PLoS One 2011; 6:e21812. [PMID: 21818266 PMCID: PMC3144881 DOI: 10.1371/journal.pone.0021812] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Accepted: 06/13/2011] [Indexed: 12/02/2022] Open
Abstract
Background Psalmopeotoxin I (PcFK1), a protein of 33 aminoacids derived from the venom of the spider Psalmopoeus Cambridgei, is able to inhibit the growth of Plasmodium falciparum malaria parasites with an IC in the low micromolar range. PcFK1 was proposed to act as an ion channel inhibitor, although experimental validation of this mechanism is lacking. The surface loops of PcFK1 have some sequence similarity with the parasite protein sequences cleaved by PfSUB1, a subtilisin-like protease essential for egress of Plasmodium falciparum merozoites and invasion into erythrocytes. As PfSUB1 has emerged as an interesting drug target, we explored the hypothesis that PcFK1 targeted PfSUB1 enzymatic activity. Findings Molecular modeling and docking calculations showed that one loop could interact with the binding site of PfSUB1. The calculated free energy of binding averaged −5.01 kcal/mol, corresponding to a predicted low-medium micromolar constant of inhibition. PcFK1 inhibited the enzymatic activity of the recombinant PfSUB1 enzyme and the in vitro P.falciparum culture in a range compatible with our bioinformatics analysis. Using contact analysis and free energy decomposition we propose that residues A14 and Q15 are important in the interaction with PfSUB1. Conclusions Our computational reverse engineering supported the hypothesis that PcFK1 targeted PfSUB1, and this was confirmed by experimental evidence showing that PcFK1 inhibits PfSUB1 enzymatic activity. This outlines the usefulness of advanced bioinformatics tools to predict the function of a protein structure. The structural features of PcFK1 represent an interesting protein scaffold for future protein engineering.
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Affiliation(s)
- Giacomo Bastianelli
- Unité de Bioinformatique Structurale, Département de Biologie Structurale et Chimie, Paris, France
- CNRS, URA2185, Paris, France
| | - Anthony Bouillon
- Unité d'Immunologie Moleculaires des Parasites, Département de Parasitologie et de Mycologie, Paris, France
- CNRS, URA2581, Paris, France
| | | | - Elodie Crublet
- Institut Pasteur, Plate-Forme 5 - Production de Protéines Recombinantes et d'Anticorps, Paris, France
| | - Stéphane Pêtres
- Institut Pasteur, Plate-Forme 5 - Production de Protéines Recombinantes et d'Anticorps, Paris, France
| | - Olivier Gorgette
- Unité d'Immunologie Moleculaires des Parasites, Département de Parasitologie et de Mycologie, Paris, France
- CNRS, URA2581, Paris, France
| | | | - Jean-Christophe Barale
- Unité d'Immunologie Moleculaires des Parasites, Département de Parasitologie et de Mycologie, Paris, France
- CNRS, URA2581, Paris, France
| | - Michael Nilges
- Unité de Bioinformatique Structurale, Département de Biologie Structurale et Chimie, Paris, France
- CNRS, URA2185, Paris, France
- * E-mail:
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15
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Tsuji N, Miyoshi T, Battsetseg B, Matsuo T, Xuan X, Fujisaki K. A cysteine protease is critical for Babesia spp. transmission in Haemaphysalis ticks. PLoS Pathog 2008; 4:e1000062. [PMID: 18483546 PMCID: PMC2358973 DOI: 10.1371/journal.ppat.1000062] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Accepted: 04/09/2008] [Indexed: 11/25/2022] Open
Abstract
Vector ticks possess a unique system that enables them to digest large amounts of host blood and to transmit various animal and human pathogens, suggesting the existence of evolutionally acquired proteolytic mechanisms. We report here the molecular and reverse genetic characterization of a multifunctional cysteine protease, longipain, from the babesial parasite vector tick Haemaphysalis longicornis. Longipain shares structural similarity with papain-family cysteine proteases obtained from invertebrates and vertebrates. Endogenous longipain was mainly expressed in the midgut epithelium and was specifically localized at lysosomal vacuoles and possibly released into the lumen. Its expression was up-regulated by host blood feeding. Enzymatic functional assays using in vitro and in vivo substrates revealed that longipain hydrolysis occurs over a broad range of pH and temperature. Haemoparasiticidal assays showed that longipain dose-dependently killed tick-borne Babesia parasites, and its babesiacidal effect occurred via specific adherence to the parasite membranes. Disruption of endogenous longipain by RNA interference revealed that longipain is involved in the digestion of the host blood meal. In addition, the knockdown ticks contained an increased number of parasites, suggesting that longipain exerts a killing effect against the midgut-stage Babesia parasites in ticks. Our results suggest that longipain is essential for tick survival, and may have a role in controlling the transmission of tick-transmittable Babesia parasites. Ticks are important ectoparasites among the blood-feeding arthropods and serve as vectors of many deadly diseases of humans and animals. Of tick-transmitted pathogens, Babesia, an intracellular haemoprotozoan parasite causing a malaria-like disease, called babesiosis, gain increasing interest due to its zoonotic significance. When vector ticks acquire the protozoa via blood-meals, they invade midgut and undergo several developmental stages prior to exit through salivary glands. It has long been conceived that midguts of these ticks evolve diverse innate immune mechanisms and perform blood digestion critical for tick survival. A cysteine proteinase, longipain, was identified from the three-host tick Haemaphysalis longicornis, which shows potent parasiticidal activity. Longipain is localized in midgut epithelium and its expression is induced by blood feeding. This protein is passively secreted into midgut lumen where it exerts enzymatic degradation of blood-meals. A series of experiments unveil that longipain-knockdown ticks when fed on Babesia-infected dog, exhibited a significantly increased numbers of parasites compared with controls. Longipain has shown to interact on the surface of Babesia parasites in vitro and in vivo, and is thought to mediate direct killing of the parasites, suggesting that longipain may be a potential chemotherapeutic target against babesiosis and ticks themselves.
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Affiliation(s)
- Naotoshi Tsuji
- Laboratory of Parasitic Diseases, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
| | - Takeharu Miyoshi
- Laboratory of Parasitic Diseases, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan
| | - Badger Battsetseg
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Tomohide Matsuo
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
- Department of Infectious Diseases, Kyorin University School of Medicine, Mitaka, Tokyo, Japan
| | - Xuenan Xuan
- Department of Infectious Diseases, Kyorin University School of Medicine, Mitaka, Tokyo, Japan
| | - Kozo Fujisaki
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
- Department of Emerging Infectious Diseases, School of Veterinary Medicine, Kagoshima University, Korimoto, Kagoshima, Japan
- * E-mail:
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Nakamura K, Yokoyama N, Igarashi I. Cyclin-dependent kinase inhibitors block erythrocyte invasion and intraerythrocytic development of Babesia bovis in vitro. Parasitology 2007; 134:1347-53. [PMID: 17634158 DOI: 10.1017/s0031182007002831] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARYCyclin-dependent kinases (CDKs) are essential for the regulation of the eukaryotic cell cycle. A number of chemicals, which selectively inhibit the CDK activities, have been synthesized for the development of anti-cancer drugs. This report describes the inhibitory effect of purine derivatives known to be CDK inhibitors on the asexual growth of Babesia bovis. The 4 compounds, roscovitine, purvalanol A, CGP74514A, and CDK2 Inhibitor II, showed significantly suppressive effects on the in vitro growth of B. bovis. Three (roscovitine, purvalanol A, and CDK2 Inhibitor II) showed an inhibitory effect on the early stages of intraerythrocytic development of B. bovis. CGP74514A (CDK1-specific inhibitor) blocked the erythrocyte invasion by merozoites. Our data suggest the chemotherapeutic potential of the CDK inhibitors for babesiosis, and the target molecules of the compounds would participate in the process of successful erythrocyte invasion or intraerythrocytic development of B. bovis.
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Affiliation(s)
- K Nakamura
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan
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17
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Rodriguez LE, Vera R, Valbuena J, Curtidor H, Garcia J, Puentes A, Ocampo M, Lopez R, Rosas J, Lopez Y, Patarroyo MA, Patarroyo ME. Characterisation of Plasmodium falciparum RESA-like protein peptides that bind specifically to erythrocytes and inhibit invasion. Biol Chem 2007; 388:15-24. [PMID: 17214545 DOI: 10.1515/bc.2007.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The Plasmodium falciparum ring-erythrocyte surface antigen (RESA)-like putative protein was identified and characterised. PCR and RT-PCR assays revealed that the gene encoding this protein was both present and being transcribed in P. falciparum strain FCB-2 16 h after erythrocyte invasion. Indirect immunofluorescence studies detected this protein in infected erythrocyte (IE) cytosol in dense fluorescent granules similar to Maurer's clefts at 16-20 h (parasites in ring and trophozoite stages) and very strongly on IE membranes at 22 h, suggesting that it is synthesised during early ring stages (16 h) and transported to the infected red blood cell (RBC) membrane surface during the trophozoite stage (22 h). Western blotting showed that antisera produced against polymerised synthetic peptides of this protein recognised a 72-kDa band in P. falciparum schizont lysate. P. falciparum RESA-like peptides used in normal RBC binding assays revealed that peptides 30326 ((101)NAEKI LGFDD KNILE ALDLFY(120)), 30334 ((281)RVTWK KLRTK MIKAL KKSLTY(300)) and 30342 ((431)SSPQR LKFTA GGGFC GKLRNY(450)) bind with high activity and saturability, presenting nM affinity constants. These peptides contain alpha-helical structural elements, as determined by circular dichroism, and inhibit P. falciparum in vitro invasion of normal RBCs by up to 91%, suggesting that some RESA-like protein regions are involved in intra-erythrocyte stage P. falciparum invasion.
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Affiliation(s)
- Luis Eduardo Rodriguez
- Fundación Instituto de Inmunologia de Colombia and Universidad Nacional de Colombia, Carrera 50 No. 26-00, Bogotá, Colombia
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Vogt AM, Pettersson F, Moll K, Jonsson C, Normark J, Ribacke U, Egwang TG, Ekre HP, Spillmann D, Chen Q, Wahlgren M. Release of sequestered malaria parasites upon injection of a glycosaminoglycan. PLoS Pathog 2006; 2:e100. [PMID: 17009869 PMCID: PMC1579244 DOI: 10.1371/journal.ppat.0020100] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Accepted: 08/16/2006] [Indexed: 11/24/2022] Open
Abstract
Severe human malaria is attributable to an excessive sequestration of Plasmodium falciparum–infected and uninfected erythrocytes in vital organs. Strains of P. falciparum that form rosettes and employ heparan sulfate as a host receptor are associated with development of severe forms of malaria. Heparin, which is similar to heparan sulfate in that it is composed of the same building blocks, was previously used in the treatment of severe malaria, but it was discontinued due to the occurrence of serious side effects such as intracranial bleedings. Here we report to have depolymerized heparin by periodate treatment to generate novel glycans (dGAG) that lack anticoagulant-activity. The dGAGs disrupt rosettes, inhibit merozoite invasion of erythrocytes and endothelial binding of P. falciparum–infected erythrocytes in vitro, and reduce sequestration in in vivo models of severe malaria. An intravenous injection of dGAGs blocks up to 80% of infected erythrocytes from binding in the micro-vasculature of the rat and releases already sequestered parasites into circulation. P. falciparum–infected human erythrocytes that sequester in the non-human primate Macaca fascicularis were similarly found to be released in to the circulation upon a single injection of 500 μg of dGAG. We suggest dGAGs to be promising candidates for adjunct therapy in severe malaria. Severe Plasmodium falciparum malaria is common and in part the result of an excessive binding of infected erythrocytes in the microvasculature. The parasite employs heparan sulfate during the adherence to the vascular endothelium and to erythrocytes. Heparin, which is related to heparan sulfate in that it is composed of the same building blocks, was here periodate-treated to generate depolymerized glycosaminoglycans (dGAGs) that possess no anticoagulant activity. The dGAGs disrupt erythrocyte and endothelial binding of P. falciparum–infected erythrocytes in vitro. An intravenous injection of dGAGs blocks infected erythrocytes from binding in the micro-vasculature of the rat and releases already sequestrated parasites into circulation both in the rat and in a non-human primate. If this approach is successfully translated to the clinical setting, it may offer help to patients whereby the injection of a dGAG releases already sequestered parasite-infected erythrocytes and re-establishes the micro-vascular blood flow. The authors suggest dGAGs to be promising candidates of adjunct therapy that may have an important impact on malaria mortality.
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Affiliation(s)
- Anna M Vogt
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden and Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Fredrik Pettersson
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden and Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Kirsten Moll
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden and Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Cathrine Jonsson
- Department of Nuclear Medicine, Karolinska University Hospital, Solna, Sweden
| | - Johan Normark
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden and Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Ulf Ribacke
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden and Swedish Institute for Infectious Disease Control, Solna, Sweden
| | | | | | - Dorothe Spillmann
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Qijun Chen
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden and Swedish Institute for Infectious Disease Control, Solna, Sweden
| | - Mats Wahlgren
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institutet, Stockholm, Sweden and Swedish Institute for Infectious Disease Control, Solna, Sweden
- * To whom correspondence should be addressed. E-mail:
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Crandall IE, Szarek WA, Vlahakis JZ, Xu Y, Vohra R, Sui J, Kisilevsky R. Sulfated cyclodextrins inhibit the entry of Plasmodium into red blood cells. Implications for malarial therapy. Biochem Pharmacol 2006; 73:632-42. [PMID: 17166484 DOI: 10.1016/j.bcp.2006.10.030] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 10/27/2006] [Accepted: 10/30/2006] [Indexed: 11/19/2022]
Abstract
The effect of sulfated cyclodextrins on Plasmodium falciparum cultures was determined. alpha-, beta-, and gamma-Cyclodextrins having equal degrees of sulfation inhibited parasite viability to a similar degree, a result suggesting that the ring size of the cyclodextrin is not a critical factor for inhibitory activity. beta-Cyclodextrins containing fewer than two sulfate groups had no inhibitory activity, however, compounds containing 7-17 sulfates were found to be active in the microM range. Examination of treated cultures indicated that intracellular forms of the parasite were unaffected; however, increased numbers of extracellular merozoites were present. Active compounds produced enhanced erythrocyte staining with cationic dyes that could be reduced by stilbene disulfonates, a result suggesting that sulfated cyclodextrins inhibit parasite growth by interacting with the anion transport protein, AE1. Compounds that were found to be active in P. falciparum cultures were also found to inhibit P. berghei merozoite entry and could reduce the parasitemia of P. berghei infection in a mouse model, results suggesting that these compounds inhibit a common step in the merozoite invasion process of at least two Plasmodium species.
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Affiliation(s)
- Ian E Crandall
- Toronto Medical Laboratories and Tropical Disease Unit, Division of Infectious Diseases, Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
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Kruttlin EA, Rossano MG, Murphy AJ, Vrable RA, Kaneene JB, Schott HC, Mansfield LS. The effects of pyrantel tartrate on Sarcocystis neurona merozoite viability. Vet Ther 2001; 2:268-276. [PMID: 19746670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Sarcocystis neurona is the etiologic agent of equine protozoal myeloencephalitis, a neurologic disease of horses. The present study was designed to test the hypothesis that pyrantel tartrate can kill S. neurona merozoites growing in equine dermal cell culture. Sarcocystis neurona merozoites were exposed to a range of concentrations of pyrantel tartrate or sodium tartrate ranging from 0.001 to 0.01 M. Merozoites were then placed onto equine dermal cell cultures and incubated for 2 weeks to check for viability. At 1 and 2 weeks after inoculation, plaque counts were compared between treatments and, between treatments and controls. Merozoites exposed to concentrations of pyrantel tartrate higher than 0.0025 M (8.91 x 10(-4) g/ml) did not produce plaques in equine dermal cells, whereas those exposed to similar concentrations of the tartrate salt or medium alone produced significant numbers of plaques. These results demonstrate that pyrantel tartrate has activity against S. neurona merozoites in vitro and suggest that it may have activity against the sporozoite stage of the parasite found in the equine gut.
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Affiliation(s)
- E A Kruttlin
- Department of Large Animal Clinical Sciences, D201 Veterinary Medicine Center, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
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