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Das A, Rajkhowa S, Sinha S, Zaki MEA. Unveiling potential repurposed drug candidates for Plasmodium falciparum through in silico evaluation: A synergy of structure-based approaches, structure prediction, and molecular dynamics simulations. Comput Biol Chem 2024; 110:108048. [PMID: 38471353 DOI: 10.1016/j.compbiolchem.2024.108048] [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: 11/16/2023] [Revised: 02/28/2024] [Accepted: 02/29/2024] [Indexed: 03/14/2024]
Abstract
The rise of drug resistance in Plasmodium falciparum, rendering current treatments ineffective, has hindered efforts to eliminate malaria. To address this issue, the study employed a combination of Systems Biology approach and a structure-based pharmacophore method to identify a target against P. falciparum. Through text mining, 448 genes were extracted, and it was discovered that plasmepsins, found in the Plasmodium genus, play a crucial role in the parasite's survival. The metabolic pathways of these proteins were determined using the PlasmoDB genomic database and recreated using CellDesigner 4.4.2. To identify a potent target, Plasmepsin V (PF13_0133) was selected and examined for protein-protein interactions (PPIs) using the STRING Database. Topological analysis and global-based methods identified PF13_0133 as having the highest centrality. Moreover, the static protein knockout PPIs demonstrated the essentiality of PF13_0133 in the modeled network. Due to the unavailability of the protein's crystal structure, it was modeled and subjected to a molecular dynamics simulation study. The structure-based pharmacophore modeling utilized the modeled PF13_0133 (PfPMV), generating 10 pharmacophore hypotheses with a library of active and inactive compounds against PfPMV. Through virtual screening, two potential candidates, hesperidin and rutin, were identified as potential drugs which may be repurposed as potential anti-malarial agents.
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Affiliation(s)
- Abhichandan Das
- Centre for Biotechnology and Bioinformatics, Dibrugarh University, Dibrugarh, Assam 786004, India
| | - Sanchaita Rajkhowa
- Centre for Biotechnology and Bioinformatics, Dibrugarh University, Dibrugarh, Assam 786004, India.
| | - Subrata Sinha
- Department of Computational Sciences, Brainware University, Barasat, Kolkata, West Bengal 700125, India
| | - Magdi E A Zaki
- Department of Chemistry, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia
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2
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Almuqdadi HTA, Kifayat S, Anwer R, Alrehaili J, Abid M. Fragment-based virtual screening identifies novel leads against Plasmepsin IX (PlmIX) of Plasmodium falciparum: Homology modeling, molecular docking, and simulation approaches. Front Pharmacol 2024; 15:1387629. [PMID: 38846093 PMCID: PMC11153788 DOI: 10.3389/fphar.2024.1387629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Accepted: 04/24/2024] [Indexed: 06/09/2024] Open
Abstract
Despite continuous efforts to develop safer and efficient medications, malaria remains a major threat posing great challenges for new drug discovery. The emerging drug resistance, increased toxicities, and impoverished pharmacokinetic profiles exhibited by conventional drugs have hindered the search for new entities. Plasmepsins, a group of Plasmodium-specific, aspartic acid protease enzymes, are involved in many key aspects of parasite biology, and this makes them interesting targets for antimalarial chemotherapy. Among different isoforms, PlmIX serves as an unexplored antimalarial drug target that plays a crucial role along with PlmV and X in the parasite's survival by digesting hemoglobin in the host's erythrocytes. In this study, fragment-based virtual screening was performed by modeling the three-dimensional structure of PlmIX and predicting its ligand-binding pocket by using the Sitemap tool. Screening identified the fragments with the XP docking score ≤ -3 kcal/mol from the OTAVA General Fragment Library (≈16,397 fragments), and the selected fragments were chosen for ligand breeding. The resulting ligands (≈69,858 ligands) were subsequently subjected to filtering based on the QikProp properties along with carcinogenicity testing performed using CarcinoPred-EL and then docked in the SP (≈14,078 ligands) as well as XP mode (≈3,104 ligands), and compared with that of control ligands 49C and I0L. The top-ranked ligands were taken further for the calculation of the free energy of binding using Prime MM-GBSA. Overall, a total of six complexes were taken further for MD simulation studies performed at 100 ns to attain a better understanding of the binding mechanisms, and compounds 3 and 4 were found to be the most efficient ones in silico. The analysis of compound 3 revealed that the carbonyl group present in position 1 on the isoindoline moiety (Arg554) was responsible for inhibitory activity against PlmIX. However, the analysis of compound 4 revealed that the amide linkage sandwiched between the phenyl ring and isoquinoline moiety (Lys555 and Ser226) as well as carbonyl oxygen of the carbamoyl group present at position 2 of the pyrazole ring (Gln222) were responsible for PlmIX inhibitory activity, owing to their crucial interactions with key amino acid residues.
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Affiliation(s)
- Haider Thaer Abdulhameed Almuqdadi
- Medicinal Chemistry Laboratory, Department of Biosciences, Jamia Millia Islamia, New Delhi, India
- Department of Chemistry, College of Science, Al-Nahrain University, Baghdad, Iraq
| | - Sumaiya Kifayat
- Medicinal Chemistry Laboratory, Department of Biosciences, Jamia Millia Islamia, New Delhi, India
| | - Razique Anwer
- Department of Pathology, College of Medicine, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia
| | - Jihad Alrehaili
- Department of Pathology, College of Medicine, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia
| | - Mohammad Abid
- Medicinal Chemistry Laboratory, Department of Biosciences, Jamia Millia Islamia, New Delhi, India
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3
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Sulyman AO, Aje OO, Ajani EO, Abdulsalam RA, Balogun FO, Sabiu S. Bioprospection of Selected Plant Secondary Metabolites as Modulators of the Proteolytic Activity of Plasmodium falciparum Plasmepsin V. BIOMED RESEARCH INTERNATIONAL 2023; 2023:6229503. [PMID: 37388365 PMCID: PMC10307063 DOI: 10.1155/2023/6229503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/25/2023] [Accepted: 06/01/2023] [Indexed: 07/01/2023]
Abstract
Malaria is a devastating disease, and its management is only achieved through chemotherapy. However, resistance to available medication is still a challenge; therefore, there is an urgent need for the discovery and development of therapeutics with a novel mechanism of action to counter the resistance scourge consistent with the currently available antimalarials. Recently, plasmepsin V was validated as a therapeutic target for the treatment of malaria. The pepsin-like aspartic protease anchored in the endoplasmic reticulum is responsible for the trafficking of parasite-derived proteins to the erythrocytic surface of the host cells. In this study, a small library of compounds was preliminarily screened in vitro to identify novel modulators of Plasmodium falciparum plasmepsin V (PfPMV). The results obtained revealed kaempferol, quercetin, and shikonin as possible PfPMV inhibitors, and these compounds were subsequently probed for their inhibitory potentials using in vitro and in silico methods. Kaempferol and shikonin noncompetitively and competitively inhibited the specific activity of PfPMV in vitro with IC50 values of 22.4 and 43.34 μM, respectively, relative to 62.6 μM obtained for pepstatin, a known aspartic protease inhibitor. Further insight into the structure-activity relationship of the compounds through a 100 ns molecular dynamic (MD) simulation showed that all the test compounds had a significant affinity for PfPMV, with quercetin (-36.56 kcal/mol) being the most prominent metabolite displaying comparable activity to pepstatin (-35.72 kcal/mol). This observation was further supported by the compactness and flexibility of the resulting complexes where the compounds do not compromise the structural integrity of PfPMV but rather stabilized and interacted with the active site amino acid residues critical to PfPMV modulation. Considering the findings in this study, quercetin, kaempferol, and shikonin could be proposed as novel aspartic protease inhibitors worthy of further investigation in the treatment of malaria.
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Affiliation(s)
- Abdulhakeem Olarewaju Sulyman
- Department of Biochemistry, Faculty of Pure and Applied Sciences, Kwara State University, P.M.B. 1530, Malete, Ilorin, Nigeria
| | - Oluwapelumi Oluwaseun Aje
- Department of Biochemistry, Faculty of Pure and Applied Sciences, Kwara State University, P.M.B. 1530, Malete, Ilorin, Nigeria
| | - Emmanuel Oladipo Ajani
- Department of Biochemistry, Faculty of Pure and Applied Sciences, Kwara State University, P.M.B. 1530, Malete, Ilorin, Nigeria
| | - Rukayat Abiola Abdulsalam
- Department of Biotechnology and Food Science, Faculty of Applied Sciences, Durban University of Technology, Durban, South Africa
| | - Fatai Oladunni Balogun
- Department of Biotechnology and Food Science, Faculty of Applied Sciences, Durban University of Technology, Durban, South Africa
| | - Saheed Sabiu
- Department of Biotechnology and Food Science, Faculty of Applied Sciences, Durban University of Technology, Durban, South Africa
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Levray YS, Bana B, Tarr SJ, McLaughlin EJ, Rossi-Smith P, Waltho A, Charlton GH, Chiozzi RZ, Straton CR, Thalassinos K, Osborne AR. Formation of ER-lumenal intermediates during export of Plasmodium proteins containing transmembrane-like hydrophobic sequences. PLoS Pathog 2023; 19:e1011281. [PMID: 37000891 PMCID: PMC10096305 DOI: 10.1371/journal.ppat.1011281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 04/12/2023] [Accepted: 03/08/2023] [Indexed: 04/03/2023] Open
Abstract
During the blood stage of a malaria infection, malaria parasites export both soluble and membrane proteins into the erythrocytes in which they reside. Exported proteins are trafficked via the parasite endoplasmic reticulum and secretory pathway, before being exported across the parasitophorous vacuole membrane into the erythrocyte. Transport across the parasitophorous vacuole membrane requires protein unfolding, and in the case of membrane proteins, extraction from the parasite plasma membrane. We show that trafficking of the exported Plasmodium protein, Pf332, differs from that of canonical eukaryotic soluble-secreted and transmembrane proteins. Pf332 is initially ER-targeted by an internal hydrophobic sequence that unlike a signal peptide, is not proteolytically removed, and unlike a transmembrane segment, does not span the ER membrane. Rather, both termini of the hydrophobic sequence enter the ER-lumen and the ER-lumenal species is a productive intermediate for protein export. Furthermore, we show in intact cells, that two other exported membrane proteins, SBP1 and MAHRP2, assume a lumenal topology within the parasite secretory pathway. Although the addition of a C-terminal ER-retention sequence, recognised by the lumenal domain of the KDEL receptor, does not completely block export of SBP1 and MAHRP2, it does enhance their retention in the parasite ER. This indicates that a sub-population of each protein adopts an ER-lumenal state that is an intermediate in the export process. Overall, this suggests that although many exported proteins traverse the parasite secretory pathway as typical soluble or membrane proteins, some exported proteins that are ER-targeted by a transmembrane segment-like, internal, non-cleaved hydrophobic segment, do not integrate into the ER membrane, and form an ER-lumenal species that is a productive export intermediate. This represents a novel means, not seen in typical membrane proteins found in model systems, by which exported transmembrane-like proteins can be targeted and trafficked within the lumen of the secretory pathway.
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5
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Polino AJ, Hasan MM, Floyd K, Avila-Cruz Y, Yang Y, Goldberg DE. An essential endoplasmic reticulum-resident N-acetyltransferase ortholog in Plasmodium falciparum. J Cell Sci 2023; 136:286919. [PMID: 36744402 PMCID: PMC10038149 DOI: 10.1242/jcs.260551] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 01/27/2023] [Indexed: 02/07/2023] Open
Abstract
N-terminal acetylation is a common eukaryotic protein modification that involves the addition of an acetyl group to the N-terminus of a polypeptide. This modification is largely performed by cytosolic N-terminal acetyltransferases (NATs). Most associate with the ribosome, acetylating nascent polypeptides co-translationally. In the malaria parasite Plasmodium falciparum, exported effectors are thought to be translated into the endoplasmic reticulum (ER), processed by the aspartic protease plasmepsin V and then N-acetylated, despite having no clear access to cytosolic NATs. Here, we used inducible gene deletion and post-transcriptional knockdown to investigate the primary ER-resident NAT candidate, Pf3D7_1437000. We found that it localizes to the ER and is required for parasite growth. However, depletion of Pf3D7_1437000 had no effect on protein export or acetylation of the exported proteins HRP2 and HRP3. Despite this, Pf3D7_1437000 depletion impedes parasite development within the host red blood cell and prevents parasites from completing genome replication. Thus, this work provides further proof of N-terminal acetylation of secretory system proteins, a process unique to apicomplexan parasites, but strongly discounts a promising candidate for this post-translational modification.
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Affiliation(s)
- Alexander J Polino
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Muhammad M Hasan
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Katherine Floyd
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Yolotzin Avila-Cruz
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Yujuan Yang
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Daniel E Goldberg
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110, USA
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Richardson LW, Ashton TD, Dans MG, Nguyen N, Favuzza P, Triglia T, Hodder AN, Ngo A, Jarman KE, Cowman AF, Sleebs BE. Substrate Peptidomimetic Inhibitors of P. falciparum Plasmepsin X with Potent Antimalarial Activity. ChemMedChem 2022; 17:e202200306. [PMID: 35906744 PMCID: PMC9804387 DOI: 10.1002/cmdc.202200306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 07/29/2022] [Indexed: 01/07/2023]
Abstract
Plasmepsin X (PMX) is an aspartyl protease that processes proteins essential for Plasmodium parasites to invade and egress from host erythrocytes during the symptomatic asexual stage of malaria. PMX substrates possess a conserved cleavage region denoted by the consensus motif, SFhE (h=hydrophobic amino acid). Peptidomimetics reflecting the P3 -P1 positions of the consensus motif were designed and showed potent and selective inhibition of PMX. It was established that PMX prefers Phe in the P1 position, di-substitution at the β-carbon of the P2 moiety and a hydrophobic P3 group which was supported by modelling of the peptidomimetics in complex with PMX. The peptidomimetics were shown to arrest asexual P. falciparum parasites at the schizont stage by impairing PMX substrate processing. Overall, the peptidomimetics described will assist in further understanding PMX substrate specificity and have the potential to act as a template for future antimalarial design.
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Affiliation(s)
- Lachlan W. Richardson
- Walter and Eliza Hall Institute of Medical ResearchParkville3052VictoriaAustralia,Department of Medical BiologyUniversity of MelbourneParkville3010VictoriaAustralia
| | - Trent D. Ashton
- Walter and Eliza Hall Institute of Medical ResearchParkville3052VictoriaAustralia,Department of Medical BiologyUniversity of MelbourneParkville3010VictoriaAustralia
| | - Madeline G. Dans
- Walter and Eliza Hall Institute of Medical ResearchParkville3052VictoriaAustralia,Department of Medical BiologyUniversity of MelbourneParkville3010VictoriaAustralia
| | - Nghi Nguyen
- Walter and Eliza Hall Institute of Medical ResearchParkville3052VictoriaAustralia,Department of Medical BiologyUniversity of MelbourneParkville3010VictoriaAustralia
| | - Paola Favuzza
- Walter and Eliza Hall Institute of Medical ResearchParkville3052VictoriaAustralia,Department of Medical BiologyUniversity of MelbourneParkville3010VictoriaAustralia
| | - Tony Triglia
- Walter and Eliza Hall Institute of Medical ResearchParkville3052VictoriaAustralia
| | - Anthony N. Hodder
- Walter and Eliza Hall Institute of Medical ResearchParkville3052VictoriaAustralia,Department of Medical BiologyUniversity of MelbourneParkville3010VictoriaAustralia
| | - Anna Ngo
- Walter and Eliza Hall Institute of Medical ResearchParkville3052VictoriaAustralia
| | - Kate E. Jarman
- Walter and Eliza Hall Institute of Medical ResearchParkville3052VictoriaAustralia,Department of Medical BiologyUniversity of MelbourneParkville3010VictoriaAustralia
| | - Alan F. Cowman
- Walter and Eliza Hall Institute of Medical ResearchParkville3052VictoriaAustralia,Department of Medical BiologyUniversity of MelbourneParkville3010VictoriaAustralia
| | - Brad E. Sleebs
- Walter and Eliza Hall Institute of Medical ResearchParkville3052VictoriaAustralia,Department of Medical BiologyUniversity of MelbourneParkville3010VictoriaAustralia
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7
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Polino AJ, Miller JJ, Bhakat S, Mukherjee S, Bobba S, Bowman GR, Goldberg DE. The nepenthesin insert in the Plasmodium falciparum aspartic protease plasmepsin V is necessary for enzyme function. J Biol Chem 2022; 298:102355. [PMID: 35952758 PMCID: PMC9478907 DOI: 10.1016/j.jbc.2022.102355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 08/01/2022] [Accepted: 08/02/2022] [Indexed: 11/19/2022] Open
Abstract
Plasmepsin V (PM V) is a pepsin-like aspartic protease essential for growth of the malarial parasite Plasmodium falciparum. Previous work has shown PM V to be an endoplasmic reticulum-resident protease that processes parasite proteins destined for export into the host cell. Depletion or inhibition of the enzyme is lethal during asexual replication within red blood cells as well as during the formation of sexual stage gametocytes. The structure of the Plasmodium vivax PM V has been characterized by X-ray crystallography, revealing a canonical pepsin fold punctuated by structural features uncommon to secretory aspartic proteases; however, the function of this unique structure is unclear. Here, we used parasite genetics to probe these structural features by attempting to rescue lethal PM V depletion with various mutant enzymes. We found an unusual nepenthesin 1-type insert in the PM V gene to be essential for parasite growth and PM V activity. Mutagenesis of the nepenthesin insert suggests that both its amino acid sequence and one of the two disulfide bonds that undergird its structure are required for the insert's role in PM V function. Furthermore, molecular dynamics simulations paired with Markov state modeling suggest that mutations to the nepenthesin insert may allosterically affect PM V catalysis through multiple mechanisms. Taken together, these data provide further insights into the structure of the P. falciparum PM V protease.
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Affiliation(s)
- Alexander J Polino
- Division of Infectious Diseases, Department of Medicine and Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Justin J Miller
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Soumendranath Bhakat
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sumit Mukherjee
- Division of Infectious Diseases, Department of Medicine and Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Suhas Bobba
- Division of Infectious Diseases, Department of Medicine and Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Gregory R Bowman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Daniel E Goldberg
- Division of Infectious Diseases, Department of Medicine and Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA.
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8
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Mukherjee S, Nguyen S, Sharma E, Goldberg DE. Maturation and substrate processing topography of the Plasmodium falciparum invasion/egress protease plasmepsin X. Nat Commun 2022; 13:4537. [PMID: 35927261 PMCID: PMC9352755 DOI: 10.1038/s41467-022-32271-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 07/22/2022] [Indexed: 11/08/2022] Open
Abstract
The malaria parasite Plasmodium invades a host erythrocyte, multiplies within a parasitophorous vacuole (PV) and then ruptures the PV and erythrocyte membranes in a process known as egress. Both egress and invasion are controlled by effector proteins discharged from specialized secretory organelles. The aspartic protease plasmepsin X (PM X) regulates activity for many of these effectors, but it is unclear how PM X accesses its diverse substrates that reside in different organelles. PM X also autoprocesses to generate different isoforms. The function of this processing is not understood. We have mapped the self-cleavage sites and have constructed parasites with cleavage site mutations. Surprisingly, a quadruple mutant that remains full-length retains in vitro activity, is trafficked normally, and supports normal egress, invasion and parasite growth. The N-terminal half of the prodomain stays bound to the catalytic domain even after processing and is required for proper intracellular trafficking of PM X. We find that this enzyme cleaves microneme and exoneme substrates before discharge, while the rhoptry substrates that are dependent on PM X activity are cleaved after exoneme discharge into the PV. The data give insight into the temporal, spatial and biochemical control of this unusual but important aspartic protease.
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Affiliation(s)
- Sumit Mukherjee
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Suong Nguyen
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Eashan Sharma
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Daniel E Goldberg
- Division of Infectious Diseases, Department of Medicine, and Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA.
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9
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Panda SK, Saxena S, Gupta PSS, Rana MK. Inhibitors of Plasmepsin X Plasmodium falciparum: Structure-based pharmacophore generation and molecular dynamics simulation. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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10
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Sojka D, Šnebergerová P, Robbertse L. Protease Inhibition-An Established Strategy to Combat Infectious Diseases. Int J Mol Sci 2021; 22:5762. [PMID: 34071206 PMCID: PMC8197795 DOI: 10.3390/ijms22115762] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 12/29/2022] Open
Abstract
Therapeutic agents with novel mechanisms of action are urgently needed to counter the emergence of drug-resistant infections. Several decades of research into proteases of disease agents have revealed enzymes well suited for target-based drug development. Among them are the three recently validated proteolytic targets: proteasomes of the malarial parasite Plasmodium falciparum, aspartyl proteases of P. falciparum (plasmepsins) and the Sars-CoV-2 viral proteases. Despite some unfulfilled expectations over previous decades, the three reviewed targets clearly demonstrate that selective protease inhibitors provide effective therapeutic solutions for the two most impacting infectious diseases nowadays-malaria and COVID-19.
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Affiliation(s)
- Daniel Sojka
- Biology Centre, Institute of Parasitology, Academy of Sciences of the Czech Republic, Branišovská 1160/31, CZ-37005 České Budějovice, Czech Republic; (P.Š.); (L.R.)
| | - Pavla Šnebergerová
- Biology Centre, Institute of Parasitology, Academy of Sciences of the Czech Republic, Branišovská 1160/31, CZ-37005 České Budějovice, Czech Republic; (P.Š.); (L.R.)
- Faculty of Science, University of South Bohemia in České Budějovice, Branišovská 1760c, CZ-37005 České Budějovice, Czech Republic
| | - Luïse Robbertse
- Biology Centre, Institute of Parasitology, Academy of Sciences of the Czech Republic, Branišovská 1160/31, CZ-37005 České Budějovice, Czech Republic; (P.Š.); (L.R.)
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11
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Mills B, Isaac RE, Foster R. Metalloaminopeptidases of the Protozoan Parasite Plasmodium falciparum as Targets for the Discovery of Novel Antimalarial Drugs. J Med Chem 2021; 64:1763-1785. [PMID: 33534577 DOI: 10.1021/acs.jmedchem.0c01721] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Malaria poses a significant threat to approximately half of the world's population with an annual death toll close to half a million. The emergence of resistance to front-line antimalarials in the most lethal human parasite species, Plasmodium falciparum (Pf), threatens progress made in malaria control. The prospect of losing the efficacy of antimalarial drugs is driving the search for small molecules with new modes of action. Asexual reproduction of the parasite is critically dependent on the recycling of amino acids through catabolism of hemoglobin (Hb), which makes metalloaminopeptidases (MAPs) attractive targets for the development of new drugs. The Pf genome encodes eight MAPs, some of which have been found to be essential for parasite survival. In this article, we discuss the biological structure and function of each MAP within the Pf genome, along with the drug discovery efforts that have been undertaken to identify novel antimalarial candidates of therapeutic value.
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Affiliation(s)
- Belinda Mills
- School of Chemistry, University of Leeds, Leeds, U.K., LS2 9JT
| | - R Elwyn Isaac
- School of Biology, University of Leeds, Leeds, U.K., LS2 9JT
| | - Richard Foster
- School of Chemistry, University of Leeds, Leeds, U.K., LS2 9JT
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12
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Jennison C, Lucantoni L, O'Neill MT, McConville R, Erickson SM, Cowman AF, Sleebs BE, Avery VM, Boddey JA. Inhibition of Plasmepsin V Activity Blocks Plasmodium falciparum Gametocytogenesis and Transmission to Mosquitoes. Cell Rep 2020; 29:3796-3806.e4. [PMID: 31851913 DOI: 10.1016/j.celrep.2019.11.073] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 10/14/2019] [Accepted: 11/15/2019] [Indexed: 12/20/2022] Open
Abstract
Plasmodium falciparum gametocytes infect mosquitoes and are responsible for malaria transmission. New interventions that block transmission could accelerate malaria elimination. Gametocytes develop within erythrocytes and activate protein export pathways that remodel the host cell. Plasmepsin V (PMV) is an aspartyl protease that is required for protein export in asexual parasites, but its function and essentiality in gametocytes has not been definitively proven, nor has PMV been assessed as a transmission-blocking drug target. Here, we show that PMV is expressed and can be inhibited specifically in P. falciparum stage I-II gametocytes. PMV inhibitors block processing and export of gametocyte effector proteins and inhibit development of stage II-V gametocytes. Gametocytogenesis in the presence of sublethal inhibitor concentrations results in stage V gametocytes that fail to infect mosquitoes. Therefore, PMV primes gametocyte effectors for export, which is essential for the development and fitness of gametocytes for transmission to mosquitoes.
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Affiliation(s)
- Charlie Jennison
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Leonardo Lucantoni
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan 4111, QLD, Australia
| | - Matthew T O'Neill
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia
| | - Robyn McConville
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Sara M Erickson
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia
| | - Vicky M Avery
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan 4111, QLD, Australia
| | - Justin A Boddey
- The Walter and Eliza Hall Institute of Medical Research, Parkville 3052, VIC, Australia; Department of Medical Biology, University of Melbourne, Parkville 3010, VIC, Australia.
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13
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Manhas A, Kumar S, Jha PC. Identification of the natural compound inhibitors against Plasmodium falciparum plasmepsin-II via common feature based screening and molecular dynamics simulations. J Biomol Struct Dyn 2020; 40:31-43. [PMID: 32794426 DOI: 10.1080/07391102.2020.1806110] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Malaria is counted amongst the deadly disease caused by Plasmodium falciparum. Recently, plasmepsin-II enzyme has gained much importance as an attractive drug target for the exploration of antimalarials. Therefore, the common feature pharmacophore models were generated from the crystallized complexes of the plasmepsin-II proteome. These models were subjected to a series of validation procedures, i.e. test set and Güner Henry studies to enlist the representative models. The selected representative hypotheses incorporating the most essential chemical features (common ZHHA) were screened against the natural product database to retrieve the potential candidates. To ensure the selection of the drug-like candidates, prior to screening, filtering steps (Drug-likeness and ADMET filters) were employed on the selected database. To study the interaction pattern of the candidates within the protein, these molecules were advanced to the molecular docking studies. Subsequently, based on the selected cut-off criteria obtained via redocking of the reference (4Z22), 15 compounds showed higher docking score (> -16.05 kcal/mol), and displayed the presence of hydrogen bonding with the crucial amino acids, i.e. Asp34 and Asp214. Further, the stability of the docked molecules was scrutinized via molecular dynamics simulations, and the results were compared with the reference compound 4Z22. All the docked compounds showed stable dynamics behaviour. Thus, in the present contribution, the combination of screening and stability procedures resulted in the identification of 15 hits that can serve as a new chemical space in the designing of the novel antimalarials.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Anu Manhas
- Department of Chemistry, Pandit Deendayal Petroleum University, Gujarat, India.,School of Applied Material Sciences, Central University of Gujarat, Gujarat, India
| | - Sujeet Kumar
- School of Applied Material Sciences, Central University of Gujarat, Gujarat, India
| | - Prakash C Jha
- School of Applied Material Sciences, Central University of Gujarat, Gujarat, India
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14
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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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15
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Rathore I, Mishra V, Patel C, Xiao H, Gustchina A, Wlodawer A, Yada RY, Bhaumik P. Activation mechanism of plasmepsins, pepsin-like aspartic proteases from Plasmodium, follows a unique trans-activation pathway. FEBS J 2020; 288:678-698. [PMID: 32385863 DOI: 10.1111/febs.15363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 04/11/2020] [Accepted: 05/05/2020] [Indexed: 11/29/2022]
Abstract
Plasmodium parasites that cause malaria produce plasmepsins (PMs), pepsin-like aspartic proteases that are important antimalarial drug targets due to their role in host hemoglobin degradation. The enzymes are synthesized as inactive zymogens (pro-PMs), and the mechanism of their conversion to the active, mature forms has not been clearly elucidated. Our structural investigations of vacuolar pro-PMs with truncated prosegment (pro-tPMs) reveal that the formation of the S-shaped dimer is their innate property. Further structural studies, biochemical analysis, and molecular dynamics simulations indicate that disruption of the Tyr-Asp loop (121p-4), coordinated with the movement of the loop L1 (237-247) and helix H2 (101p-113p), is responsible for the extension of the pro-mature region (harboring the cleavage site). Consequently, under acidic pH conditions, these structural changes result in the dissociation of the dimers to monomers and the protonation of the residues in the prosegment prompts its unfolding. Subsequently, we demonstrated that the active site of the monomeric pro-tPMs with the unfolded prosegment is accessible for peptide substrate binding; in contrast, the active site is blocked in folded prosegment form of pro-tPMs. Thus, we propose a novel mechanism of auto-activation of vacuolar pro-tPMs that under acidic conditions can form a catalytically competent active site. One monomer cleaves the prosegment of the other one through a trans-activation process, resulting in formation of mature enzyme. As a result, once a mature enzyme is generated, it leads to the complete conversion of all the inactive pro-tPMs to their mature form. DATABASE: Atomic coordinates and structure factors have been submitted in the Protein Data Bank (PDB) under the PDB IDs 6KUB, 6KUC, and 6KUD.
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Affiliation(s)
- Ishan Rathore
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Vandana Mishra
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Chandan Patel
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, India
| | - Huogen Xiao
- Summerland Research and Development Centre, Agriculture and Agri-Food Canada, Summerland, BC, Canada
| | - Alla Gustchina
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Alexander Wlodawer
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD, USA
| | - Rickey Y Yada
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada
| | - Prasenjit Bhaumik
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
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16
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In vitro effectivity of three approved drugs and their synergistic interaction against Leishmania infantum. ACTA ACUST UNITED AC 2020; 40:89-101. [PMID: 32463611 PMCID: PMC7449103 DOI: 10.7705/biomedica.4891] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Indexed: 12/24/2022]
Abstract
Introduction: Leishmaniasis remains one of the neglected tropical diseases. Repurposing existing drugs has proven to be successful for treating neglected tropical diseases while combination therapy is a strategic alternative for the treatment of infectious diseases. Auranofin, lopinavir/ritonavir, and sorafenib are FDA approved drugs used in the treatment of diverse diseases by acting on different essential biological enzymes. Objective: To evaluate the effects of monotherapy and combined therapies with the three drugs against Leishmania infantum. Materials and methods: We compared the leishmanicidal effects of the three drugs on promastigotes in vitro as regards the parasite count, the drug concentration providing a half-maximal response, and the ultrastructural changes of the parasite. We determined the fractional inhibitory concentration index of combined drugs in two ways, as well as the activity of the three drugs together to establish their synergetic effect. Results: The monotherapy with the three drugs was effective with auranofin showing the best leishmanicidal effect (EC50=1.5 µM), whereas sorafinib reduced parasite growth at EC50=2.5 µM. The scanning electron microscopy of promastigotes from all treated media showed distortion in the shape with loss of flagella and bleb formation. Acidocalcinosis was evident by transmission electron microscopy with all treatments suggesting apoptosis. Treatment with lopinavir/ritonavir showed signs of autophagy. The two-way combination of the drugs led to additive interactions while the combination of the three drugs showed synergistic action. Conclusion: Each drug when used as monotherapy against Leishmania spp. was effective, but the combination therapy was more effective than the individual drugs due to the additive or synergistic effects.
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17
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Cheuka PM, Dziwornu G, Okombo J, Chibale K. Plasmepsin Inhibitors in Antimalarial Drug Discovery: Medicinal Chemistry and Target Validation (2000 to Present). J Med Chem 2020; 63:4445-4467. [PMID: 31913032 DOI: 10.1021/acs.jmedchem.9b01622] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Plasmepsins represent novel antimalarial drug targets. However, plasmepsin-based antimalarial drug discovery efforts in the past 2 decades have generally suffered some drawbacks including lack of translatability of target inhibition to potent parasite inhibition in vitro and in vivo as well as poor selectivity over the related human aspartic proteases. Most studies reported in this period have over-relied on the use of hemoglobinase plasmepsins I-IV (particularly I and II) as targets for the new inhibitors even though these are known to be nonessential at the asexual stage of parasite development. Therefore, future antimalarial drug discovery efforts seeking to identify plasmepsin inhibitors should focus on incorporating non-hemoglobinase plasmepsins such as V, IX, and X in their screening in order to maximize chances of success. Additionally, there is need to go beyond just target enzymatic activity profiling to establishing cellular activity, physicochemical as well as drug metabolism and pharmacokinetics properties and finally in vivo proof-of-concept while ensuring selectivity over related human host proteases.
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Affiliation(s)
- Peter Mubanga Cheuka
- Department of Chemistry, University of Zambia, Great East Road Campus, P.O. Box 32379, Lusaka, Zambia
| | - Godwin Dziwornu
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
| | - John Okombo
- Department of Microbiology and Immunology, Columbia University, 701 West 168th Street, New York, New York 10032, United States
| | - Kelly Chibale
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.,Drug Discovery and Development Centre (H3D), Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.,Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa.,South African Medical Research Council Drug Discovery and Development Research Unit, University of Cape Town, Rondebosch 7701, South Africa
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18
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Yield improvement and enzymatic dissection of Plasmodium falciparum plasmepsin V. Mol Biochem Parasitol 2019; 231:111188. [PMID: 31108131 DOI: 10.1016/j.molbiopara.2019.111188] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 05/13/2019] [Accepted: 05/15/2019] [Indexed: 11/22/2022]
Abstract
To survive within a red blood cell (RBC), malaria parasites establish striking modifications to the permeability, rigidity and cytoadherence properties of the host cell. This is mediated by the export of hundreds of proteins from the parasite into the erythrocyte. Plasmodium falciparum plasmepsin V (PfPMV), is an ER resident aspartic protease that processes proteins for export into the host erythrocyte, plays a crucial role in parasite virulence and survival and is considered a potential malaria drug target. Most attempts at its heterologous expression in Escherichia coli have resulted in mainly the production of insoluble proteins. In this study, we employed a multipurpose fusion tag to improve the production of PfPMV in E. coli. Recombinant PfPMVm, comprising residues 84-521, was substantially obtained in soluble form and could be purified in a single step, yielding a 3.7-fold increase in purified PfPMVm compared to previous reports. Additionally, we have mutated the catalytic residues (D118N and D365N), individually and together, and the unpaired cysteine residue C178 to evaluate the effects on catalytic efficiency. Mutation of D365 had more pronounced effects on the catalytic efficiency than that of D118, suggesting that the D365 may act as a catalytic nucleophile to activate the water molecule. The importance of C178 was also confirmed by the inhibition by metal ions, indicating that C178 is partially involved in the substrate recognition. Collectively, our results describe an improved system to produce recombinant PfPMVm in E. coli and dissect the amino acids involved in catalysis and substrate recognition.
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19
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Mishra M, Singh V, Singh S. Structural Insights Into Key Plasmodium Proteases as Therapeutic Drug Targets. Front Microbiol 2019; 10:394. [PMID: 30891019 PMCID: PMC6411711 DOI: 10.3389/fmicb.2019.00394] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 02/14/2019] [Indexed: 11/13/2022] Open
Abstract
Malaria, caused by protozoan of genus Plasmodium, remains one of the highest mortality infectious diseases. Malaria parasites have a complex life cycle, easily adapt to their host’s immune system and have evolved with an arsenal of unique proteases which play crucial roles in proliferation and survival within the host cells. Owing to the existing knowledge of enzymatic mechanisms, 3D structures and active sites of proteases, they have been proven to be opportune for target based drug development. Here, we discuss in depth the crucial roles of essential proteases in Plasmodium life cycle and particularly focus on highlighting the atypical “structural signatures” of key parasite proteases which have been exploited for drug development. These features, on one hand aid parasites pathogenicity while on the other hand could be effective in designing targeted and very specific inhibitors for counteracting them. We conclude that Plasmodium proteases are suitable as multistage targets for designing novel drugs with new modes of action to combat malaria.
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Affiliation(s)
- Manasi Mishra
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Dadri, India
| | - Vigyasa Singh
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Shailja Singh
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Dadri, India.,Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
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20
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Boonyalai N, Collins CR, Hackett F, Withers-Martinez C, Blackman MJ. Essentiality of Plasmodium falciparum plasmepsin V. PLoS One 2018; 13:e0207621. [PMID: 30517136 PMCID: PMC6281190 DOI: 10.1371/journal.pone.0207621] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 11/02/2018] [Indexed: 11/19/2022] Open
Abstract
The malaria parasite replicates within erythrocytes. The pathogenesis of clinical malaria is in large part due to the capacity of the parasite to remodel its host cell. To do this, intraerythrocytic stages of Plasmodium falciparum export more than 300 proteins that dramatically alter the morphology of the infected erythrocyte as well as its mechanical and adhesive properties. P. falciparum plasmepsin V (PfPMV) is an aspartic protease that processes proteins for export into the host erythrocyte and is thought to play a key role in parasite virulence and survival. However, although standard techniques for gene disruption as well as conditional protein knockdown have been previously attempted with the pfpmv gene, complete gene removal or knockdown was not achieved so direct genetic proof that PMV is an essential protein has not been established. Here we have used a conditional gene excision approach combining CRISPR-Cas9 gene editing and DiCre-mediated recombination to functionally inactivate the pfpmv gene. The resulting mutant parasites displayed a severe growth defect. Detailed phenotypic analysis showed that development of the mutant parasites was arrested early in the ring-to-trophozoite transition in the erythrocytic cycle following gene excision. Our findings are the first to elucidate the effects of PMV gene disruption, showing that it is essential for parasite viability in asexual blood stages. The mutant parasites can now be used as a platform to further dissect the Plasmodium protein export pathway.
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Affiliation(s)
- Nonlawat Boonyalai
- Department of Biochemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, Thailand
- * E-mail: (NB), ; (MJB)
| | - Christine R. Collins
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Fiona Hackett
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
| | | | - Michael J. Blackman
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
- Department of Pathogen Molecular Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
- * E-mail: (NB), ; (MJB)
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21
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Meissner KA, Kronenberger T, Maltarollo VG, Trossini GHG, Wrenger C. Targeting the Plasmodium falciparum plasmepsin V by ligand-based virtual screening. Chem Biol Drug Des 2018; 93:300-312. [PMID: 30320974 DOI: 10.1111/cbdd.13416] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/05/2018] [Accepted: 06/09/2018] [Indexed: 12/16/2022]
Abstract
Malaria is a devastating disease depending only on chemotherapy as treatment. However, medication is losing efficacy, and therefore, there is an urgent need for the discovery of novel pharmaceutics. Recently, plasmepsin V, an aspartic protease anchored in the endoplasmaic reticulum, was demonstrated as responsible for the trafficking of parasite-derived proteins to the erythrocytic surface and further validated as a drug target. In this sense, ligand-based virtual screening has been applied to design inhibitors that target plasmepsin V of P. falciparum (PMV). After screening 5.5 million compounds, four novel plasmepsin inhibitors have been identified which were subsequently analyzed for the potency at the cellular level. Since PMV is membrane-anchored, the verification in vivo by using transgenic PMV overexpressing P. falciparum cells has been performed in order to evaluate drug efficacy. Two lead compounds, revealing IC50 values were 44.2 and 19.1 μm, have been identified targeting plasmepsin V in vivo and do not significantly affect the cell viability of human cells up to 300 μm. We herein report the use of the consensus of individual virtual screening as a new technique to design new ligands, and we propose two new lead compounds as novel protease inhibitors to target malaria.
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Affiliation(s)
- Kamila Anna Meissner
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Thales Kronenberger
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.,Department of Internal Medicine VIII, University Hospital of Tübingen, Tübingen, Germany
| | - Vinícius Gonçalves Maltarollo
- Department of Pharmaceutical Products, Faculty of Pharmacy, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | | | - Carsten Wrenger
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
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22
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Sittikul P, Songtawee N, Kongkathip N, Boonyalai N. In vitro and in silico studies of naphthoquinones and peptidomimetics toward Plasmodium falciparum plasmepsin V. Biochimie 2018; 152:159-173. [PMID: 30103899 DOI: 10.1016/j.biochi.2018.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 07/04/2018] [Indexed: 12/16/2022]
Abstract
Plasmodium proteases play both regulatory and effector roles in essential biological processes in this important pathogen and have long been investigated as drug targets. Plasmepsin V from P. falciparum (PfPMV) is an essential protease that processes proteins for export into the host erythrocyte and is a focus of ongoing drug development efforts. In the present study, recombinant protein production, inhibition assays, binding studies as well as molecular docking and molecular dynamics simulation studies were used to investigate the mode of binding of a PEXEL-based peptidomimetic and naphthoquinone compounds to PfPMV. Consistent with our previous study, refolded PfPMVs were produced with functional characteristics similar to the soluble counterpart. Naphthoquinone compounds inhibited PfPMV activity by 50% at 50 μM but did not affect pepsin activity. The IC50 values of compounds 31 and 37 against PfPMV were 22.25 and 68.94 μM, respectively. Molecular dynamics simulations revealed that PEXEL peptide interacted with PfPMV active site residues via electrostatic interactions while naphthoquinone binding preferred van der Waal interactions. P1'-Ser of the PfEMP2 substrate formed an additional H-bond with Asp365 promoting the catalytic efficiency. Additionally, the effect of metal ions on the secondary structure of PfPMV was examined. Our results confirmed that Hg2+ ions reversibly induced the changes in secondary structure of the protein whereas Fe3+ ions induced irreversibly. No change was observed in the presence of Ca2+ ions. Overall, the results here suggested that naphthoquinone derivatives may represent another source of antimalarial inhibitors targeting aspartic proteases but further chemical modifications are required.
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Affiliation(s)
- Pichamon Sittikul
- Department of Biochemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand; Department of Tropical Pediatrics, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Napat Songtawee
- Department of Clinical Chemistry, Faculty of Medical Technology, Mahidol University, Phuttamonthon, Nakhon Pathom, 73170, Thailand
| | - Ngampong Kongkathip
- Natural Product and Organic Synthesis Research Unit (NPOS), Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand
| | - Nonlawat Boonyalai
- Department of Biochemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand.
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23
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Sharma R, Sharma B, Gupta A, Dhar SK. Identification of a novel trafficking pathway exporting a replication protein, Orc2 to nucleus via classical secretory pathway in Plasmodium falciparum. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018. [PMID: 29524523 DOI: 10.1016/j.bbamcr.2018.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Malaria parasites use an extensive secretory pathway to traffic a number of proteins within itself and beyond. In higher eukaryotes, Endoplasmic Reticulum (ER) membrane bound transcription factors such as SREBP are reported to get processed en route and migrate to nucleus under the influence of specific cues. However, a protein constitutively trafficked to the nucleus via classical secretory pathway has not been reported. Herein, we report the presence of a novel trafficking pathway in an apicomplexan, Plasmodium falciparum where a homologue of an Origin Recognition Complex 2 (Orc2) goes to the nucleus following its association with the ER. Our work highlights the unconventional role of ER in protein trafficking and reports for the first time an ORC homologue getting trafficked through such a pathway to the nucleus where it may be involved in DNA replication and other ancillary functions. Such trafficking pathways may have a profound impact on the cell biology of a malaria parasite and have significant implications in strategizing new antimalarials.
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Affiliation(s)
- Rahul Sharma
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Bhumika Sharma
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Ashish Gupta
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Greater Noida 201314, India
| | - Suman Kumar Dhar
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India.
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24
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McGillewie L, Ramesh M, Soliman ME. Sequence, Structural Analysis and Metrics to Define the Unique Dynamic Features of the Flap Regions Among Aspartic Proteases. Protein J 2017; 36:385-396. [PMID: 28762197 DOI: 10.1007/s10930-017-9735-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Aspartic proteases are a class of hydrolytic enzymes that have been implicated in a number of diseases such as HIV, malaria, cancer and Alzheimer's. The flap region of aspartic proteases is a characteristic unique structural feature of these enzymes; and found to have a profound impact on protein overall structure, function and dynamics. Flap dynamics also plays a crucial role in drug binding and drug resistance. Therefore, understanding the structure and dynamic behavior of this flap regions is crucial in the design of potent and selective inhibitors against aspartic proteases. Defining metrics that can describe the flap motion/dynamics has been a challenging topic in literature. This review is the first attempt to compile comprehensive information on sequence, structure, motion and metrics used to assess the dynamics of the flap region of different aspartic proteases in "one pot". We believe that this review would be of critical importance to the researchers from different scientific domains.
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Affiliation(s)
- Lara McGillewie
- Molecular Modelling & Drug Design Research Group, School of Health Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban, 4001, South Africa
| | - Muthusamy Ramesh
- Molecular Modelling & Drug Design Research Group, School of Health Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban, 4001, South Africa
| | - Mahmoud E Soliman
- Molecular Modelling & Drug Design Research Group, School of Health Sciences, University of KwaZulu-Natal (UKZN), Westville, Durban, 4001, South Africa.
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25
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The Exported Chaperone PfHsp70x Is Dispensable for the Plasmodium falciparum Intraerythrocytic Life Cycle. mSphere 2017; 2:mSphere00363-17. [PMID: 28959740 PMCID: PMC5615134 DOI: 10.1128/msphere.00363-17] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 09/07/2017] [Indexed: 11/24/2022] Open
Abstract
Half of the world’s population lives at risk for malaria. The intraerythrocytic life cycle of Plasmodium spp. is responsible for clinical manifestations of malaria; therefore, knowledge of the parasite’s ability to survive within the erythrocyte is needed to combat the deadliest agent of malaria, P. falciparum. An outstanding question in the field is how P. falciparum undertakes the essential process of trafficking its proteins within the host cell. In most organisms, chaperones such as Hsp70 are employed in protein trafficking. Of the Plasmodium species causing human disease, the chaperone PfHsp70x is unique to P. falciparum, and it is the only parasite protein of its kind exported to the host (S. Külzer et al., Cell Microbiol 14:1784–1795, 2012). This has placed PfHsp70x as an ideal target to inhibit protein trafficking and kill the parasite. However, we show that PfHsp70x is not required for export of parasite effectors and it is not essential for parasite survival inside the RBC. Export of parasite proteins into the host erythrocyte is essential for survival of Plasmodium falciparum during its asexual life cycle. While several studies described key factors within the parasite that are involved in protein export, the mechanisms employed to traffic exported proteins within the host cell are currently unknown. Members of the Hsp70 family of chaperones, together with their Hsp40 cochaperones, facilitate protein trafficking in other organisms, and are thus likely used by P. falciparum in the trafficking of its exported proteins. A large group of Hsp40 proteins is encoded by the parasite and exported to the host cell, but only one Hsp70, P. falciparum Hsp70x (PfHsp70x), is exported with them. PfHsp70x is absent in most Plasmodium species and is found only in P. falciparum and closely related species that infect apes. Herein, we have utilized clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 genome editing in P. falciparum to investigate the essentiality of PfHsp70x. We show that parasitic growth was unaffected by knockdown of PfHsp70x using both the dihydrofolate reductase (DHFR)-based destabilization domain and the glmS ribozyme system. Similarly, a complete gene knockout of PfHsp70x did not affect the ability of P. falciparum to proceed through its intraerythrocytic life cycle. The effect of PfHsp70x knockdown/knockout on the export of proteins to the host red blood cell (RBC), including the critical virulence factor P. falciparum erythrocyte membrane protein 1 (PfEMP1), was tested, and we found that this process was unaffected. These data show that although PfHsp70x is the sole exported Hsp70, it is not essential for the asexual development of P. falciparum. IMPORTANCE Half of the world’s population lives at risk for malaria. The intraerythrocytic life cycle of Plasmodium spp. is responsible for clinical manifestations of malaria; therefore, knowledge of the parasite’s ability to survive within the erythrocyte is needed to combat the deadliest agent of malaria, P. falciparum. An outstanding question in the field is how P. falciparum undertakes the essential process of trafficking its proteins within the host cell. In most organisms, chaperones such as Hsp70 are employed in protein trafficking. Of the Plasmodium species causing human disease, the chaperone PfHsp70x is unique to P. falciparum, and it is the only parasite protein of its kind exported to the host (S. Külzer et al., Cell Microbiol 14:1784–1795, 2012). This has placed PfHsp70x as an ideal target to inhibit protein trafficking and kill the parasite. However, we show that PfHsp70x is not required for export of parasite effectors and it is not essential for parasite survival inside the RBC.
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Abou-El-Naga IF, El Kerdany ED, Mady RF, Shalaby TI, Zaytoun EM. The effect of lopinavir/ritonavir and lopinavir/ritonavir loaded PLGA nanoparticles on experimental toxoplasmosis. Parasitol Int 2017; 66:735-747. [PMID: 28838776 DOI: 10.1016/j.parint.2017.08.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 08/15/2017] [Accepted: 08/18/2017] [Indexed: 12/19/2022]
Abstract
A marked reduction has been achieved in the incidence and clinical course of toxoplasmic encephalitis after the introduction of protease inhibitors within the treatment regimen of HIV (HIV-PIs). This work was undertaken to study for the first time, the efficacy of HIV-PIs, lopinavir/ritonavir (L/R), as a therapeutic agent in acute experimental toxoplasmosis. Lopinavir/ritonavir (L/R) were used in the same ratio present in aluvia, a known HIV-PIs drug used in the developing countries in the treatment regimens of AID's patient. Poly lactic-co-glycolic acid (PLGA) nanoparticles were used as a delivery system to L/R therapy. L/R alone or after its encapsulation on PLGA were given to Swiss strain albino mice that were infected with RH virulent toxoplasma strain. Both forms caused parasitological improvement in both mortality rate and parasite count. The higher efficacy was achieved by using L/R PLGA together with minimizing the effective dose. There was significant reduction in the parasite count in the peritoneal fluid and the liver. Parasite viability and infectivity were also significantly reduced. The anti-toxoplasma effect of the drug was attributed to the morphological distortion of the tachyzoites as evident by the ultrastructure examination and suppressed the egress of tachyzoites. L/R also induced changes that suggest apoptosis and autophagy of tachyzoites. The parasitophorous vacuole membrane was disrupted and vesiculated. The nanotubular networks inside the parasitophorous vacuole were disrupted. Therefore, the present work opens a new possible way for the approved HIV-PIs as an alternative treatment against acute toxoplasmosis. Furthermore, it increases the list of the opportunistic parasites that can be treated by this drug. The successful in vivo effect of HIV-PIs against Toxoplasma gondii suggests that this parasite may be a target in HIV treated patients, thus decrease the possibility of toxoplasmic encephalitis development.
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Affiliation(s)
| | | | - Rasha Fadly Mady
- Medical Parasitology Department, Alexandria Faculty of Medicine, Egypt.
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Mastan BS, Narwal SK, Dey S, Kumar KA, Mishra S. Plasmodium berghei plasmepsin VIII is essential for sporozoite gliding motility. Int J Parasitol 2017; 47:239-245. [PMID: 28192122 DOI: 10.1016/j.ijpara.2016.11.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 11/21/2016] [Accepted: 11/28/2016] [Indexed: 01/03/2023]
Abstract
Plasmodium aspartic proteases, termed plasmepsins (PMs) play many critical roles such as haemoglobin degradation, cleavage of PEXEL proteins and sporozoite development in the parasite life cycle. Most of the plasmepsins are well characterized, however the role of PM VIII in Plasmodium remains unknown. Here, we elucidate the functions of PM VIII (PBANKA_132910) in the rodent malaria parasite Plasmodium berghei (Pb). By targeted gene deletion, we show that PbPM VIII is critical for sporozoite egress from an oocyst and gliding motility, which is a prerequisite for the invasion of salivary glands and subsequent transmission to the vertebrate host.
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Affiliation(s)
- Babu S Mastan
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Sunil Kumar Narwal
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Sandeep Dey
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Kota Arun Kumar
- Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
| | - Satish Mishra
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow 226031, India.
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Understanding the structural basis of substrate recognition by Plasmodium falciparum plasmepsin V to aid in the design of potent inhibitors. Sci Rep 2016; 6:31420. [PMID: 27531685 PMCID: PMC4987639 DOI: 10.1038/srep31420] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 07/20/2016] [Indexed: 11/16/2022] Open
Abstract
Plasmodium falciparum plasmepsin V (PfPMV) is an essential aspartic protease required for parasite survival, thus, considered as a potential drug target. This study reports the first detailed structural analysis and molecular dynamics simulation of PfPMV as an apoenzyme and its complexes with the substrate PEXEL as well as with the inhibitor saquinavir. The presence of pro-peptide in PfPMV may not structurally hinder the formation of a functionally competent catalytic active site. The structure of PfPMV-PEXEL complex shows that the unique positions of Glu179 and Gln222 are responsible for providing the specificity of PEXEL substrate with arginine at P3 position. The structural analysis also reveals that the S4 binding pocket in PfPMV is occupied by Ile94, Ala98, Phe370 and Tyr472, and therefore, does not allow binding of pepstatin, a potent inhibitor of most pepsin-like aspartic proteases. Among the screened inhibitors, the HIV-1 protease inhibitors and KNI compounds have higher binding affinities for PfPMV with saquinavir having the highest value. The presence of a flexible group at P2 and a bulky hydrophobic group at P3 position of the inhibitor is preferred in the PfPMV substrate binding pocket. Results from the present study will aid in the design of potent inhibitors of PMV.
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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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Export of malaria proteins requires co-translational processing of the PEXEL motif independent of phosphatidylinositol-3-phosphate binding. Nat Commun 2016; 7:10470. [PMID: 26832821 PMCID: PMC4740378 DOI: 10.1038/ncomms10470] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 12/09/2015] [Indexed: 11/08/2022] Open
Abstract
Plasmodium falciparum exports proteins into erythrocytes using the Plasmodium export element (PEXEL) motif, which is cleaved in the endoplasmic reticulum (ER) by plasmepsin V (PMV). A recent study reported that phosphatidylinositol-3-phosphate (PI(3)P) concentrated in the ER binds to PEXEL motifs and is required for export independent of PMV, and that PEXEL motifs are functionally interchangeable with RxLR motifs of oomycete effectors. Here we show that the PEXEL does not bind PI(3)P, and that this lipid is not concentrated in the ER. We find that RxLR motifs cannot mediate export in P. falciparum. Parasites expressing a mutated version of KAHRP, with the PEXEL motif repositioned near the signal sequence, prevented PMV cleavage. This mutant possessed the putative PI(3)P-binding residues but is not exported. Reinstatement of PEXEL to its original location restores processing by PMV and export. These results challenge the PI(3)P hypothesis and provide evidence that PEXEL position is conserved for co-translational processing and export.
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L. M, Soliman ME. The binding landscape of plasmepsin V and the implications for flap dynamics. MOLECULAR BIOSYSTEMS 2016; 12:1457-67. [DOI: 10.1039/c6mb00077k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Plasmepsin V belongs to the plasmepsin family of aspartic proteases.
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Affiliation(s)
- McGillewie L.
- Molecular Modelling & Drug Design Research Group
- School of Health Sciences
- University of KwaZulu-Natal
- Durban 4001
- South Africa
| | - Mahmoud E. Soliman
- Molecular Modelling & Drug Design Research Group
- School of Health Sciences
- University of KwaZulu-Natal
- Durban 4001
- South Africa
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Coffey MJ, Sleebs BE, Uboldi AD, Garnham A, Franco M, Marino ND, Panas MW, Ferguson DJP, Enciso M, O'Neill MT, Lopaticki S, Stewart RJ, Dewson G, Smyth GK, Smith BJ, Masters SL, Boothroyd JC, Boddey JA, Tonkin CJ. An aspartyl protease defines a novel pathway for export of Toxoplasma proteins into the host cell. eLife 2015; 4:e10809. [PMID: 26576949 PMCID: PMC4764566 DOI: 10.7554/elife.10809] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/18/2015] [Indexed: 02/03/2023] Open
Abstract
Infection by Toxoplasma gondii leads to massive changes to the host cell. Here, we identify a novel host cell effector export pathway that requires the Golgi-resident aspartyl protease 5 (ASP5). We demonstrate that ASP5 cleaves a highly constrained amino acid motif that has similarity to the PEXEL-motif of Plasmodium parasites. We show that ASP5 matures substrates at both the N- and C-terminal ends of proteins and also controls trafficking of effectors without this motif. Furthermore, ASP5 controls establishment of the nanotubular network and is required for the efficient recruitment of host mitochondria to the vacuole. Assessment of host gene expression reveals that the ASP5-dependent pathway influences thousands of the transcriptional changes that Toxoplasma imparts on its host cell. All these changes result in attenuation of virulence of Δasp5 tachyzoites in vivo. This work characterizes the first identified machinery required for export of Toxoplasma effectors into the infected host cell.
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Affiliation(s)
- Michael J Coffey
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Alessandro D Uboldi
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Alexandra Garnham
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Magdalena Franco
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States
| | - Nicole D Marino
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States
| | - Michael W Panas
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States
| | - David JP Ferguson
- Nuffield Department of Clinical Laboratory Science, Oxford University, John Radcliffe Hospital, Oxford, United Kingdom
| | - Marta Enciso
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Matthew T O'Neill
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Sash Lopaticki
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Rebecca J Stewart
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Grant Dewson
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Gordon K Smyth
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Mathematics and Statistics, The University of Melbourne, Melbourne, Australia
| | - Brian J Smith
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Seth L Masters
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - John C Boothroyd
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, United States
| | - Justin A Boddey
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
| | - Christopher J Tonkin
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- Department of Medical Biology, The University of Melbourne, Melbourne, Australia
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Gambini L, Rizzi L, Pedretti A, Taglialatela-Scafati O, Carucci M, Pancotti A, Galli C, Read M, Giurisato E, Romeo S, Russo I. Picomolar Inhibition of Plasmepsin V, an Essential Malaria Protease, Achieved Exploiting the Prime Region. PLoS One 2015; 10:e0142509. [PMID: 26566224 PMCID: PMC4643876 DOI: 10.1371/journal.pone.0142509] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 10/22/2015] [Indexed: 01/09/2023] Open
Abstract
Malaria is an infectious disease caused by Plasmodium parasites. It results in an annual death-toll of ~ 600,000. Resistance to all medications currently in use exists, and novel antimalarial drugs are urgently needed. Plasmepsin V (PmV) is an essential Plasmodium protease and a highly promising antimalarial target, which still lacks molecular characterization and drug-like inhibitors. PmV, cleaving the PExEl motif, is the key enzyme for PExEl-secretion, an indispensable parasitic process for virulence and infection. Here, we describe the accessibility of PmV catalytic pockets to inhibitors and propose a novel strategy for PmV inhibition. We also provide molecular and structural data suitable for future drug development. Using high-throughput platforms, we identified a novel scaffold that interferes with PmV in-vitro at picomolar ranges (~ 1,000-fold more active than available compounds). Via systematic replacement of P and P' regions, we assayed the physico-chemical requirements for PmV inhibition, achieving an unprecedented IC50 of ~20 pM. The hydroxyethylamine moiety, the hydrogen acceptor group in P2', the lipophilic groups upstream to P3, the arginine and other possible substitutions in position P3 proved to be critically important elements in achieving potent inhibition. In-silico analyses provided essential QSAR information and model validation. Our inhibitors act ‘on-target’, confirmed by cellular interference of PmV function and biochemical interaction with inhibitors. Our inhibitors are poorly performing against parasite growth, possibly due to poor stability of their peptidic component and trans-membrane permeability. The lowest IC50 for parasite growth inhibition was ~ 15μM. Analysis of inhibitor internalization revealed important pharmacokinetic features for PExEl-based molecules. Our work disclosed novel pursuable drug design strategies for highly efficient PmV inhibition highlighting novel molecular elements necessary for picomolar activity against PmV. All the presented data are discussed in respect to human aspartic proteases and previously reported inhibitors, highlighting differences and proposing new strategies for drug development.
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Affiliation(s)
- Luca Gambini
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Milan, Italy
| | - Luca Rizzi
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Milan, Italy
| | - Alessandro Pedretti
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Milan, Italy
| | - Orazio Taglialatela-Scafati
- Department of Chemistry of Natural Substances, Faculty of Pharmacy, Università di Napoli "Federico II", Naples, Italy
| | - Mario Carucci
- Department of Experimental Medicine and Biochemical Sciences, Università degli Studi di Perugia, Perugia, Italy
| | - Andrea Pancotti
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Milan, Italy
| | - Corinna Galli
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Milan, Italy
| | - Martin Read
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Emanuele Giurisato
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Sergio Romeo
- Department of Pharmaceutical Sciences, Università degli Studi di Milano, Milan, Italy
| | - Ilaria Russo
- Department of Experimental Medicine and Biochemical Sciences, Università degli Studi di Perugia, Perugia, Italy
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
- * E-mail:
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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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36
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Structural basis for plasmepsin V inhibition that blocks export of malaria proteins to human erythrocytes. Nat Struct Mol Biol 2015. [PMID: 26214367 DOI: 10.1038/nsmb.3061] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Plasmepsin V, an essential aspartyl protease of malaria parasites, has a key role in the export of effector proteins to parasite-infected erythrocytes. Consequently, it is an important drug target for the two most virulent malaria parasites of humans, Plasmodium falciparum and Plasmodium vivax. We developed a potent inhibitor of plasmepsin V, called WEHI-842, which directly mimics the Plasmodium export element (PEXEL). WEHI-842 inhibits recombinant plasmepsin V with a half-maximal inhibitory concentration of 0.2 nM, efficiently blocks protein export and inhibits parasite growth. We obtained the structure of P. vivax plasmepsin V in complex with WEHI-842 to 2.4-Å resolution, which provides an explanation for the strict requirements for substrate and inhibitor binding. The structure characterizes both a plant-like fold and a malaria-specific helix-turn-helix motif that are likely to be important in cleavage of effector substrates for export.
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Boonyalai N, Sittikul P, Yuvaniyama J. Plasmodium falciparum Plasmepsin V ( Pf PMV): Insights into recombinant expression, substrate specificity and active site structure. Mol Biochem Parasitol 2015; 201:5-15. [DOI: 10.1016/j.molbiopara.2015.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 04/02/2015] [Accepted: 05/11/2015] [Indexed: 10/23/2022]
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Tarr SJ, Osborne AR. Experimental determination of the membrane topology of the Plasmodium protease Plasmepsin V. PLoS One 2015; 10:e0121786. [PMID: 25849462 PMCID: PMC4388684 DOI: 10.1371/journal.pone.0121786] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 02/07/2015] [Indexed: 11/23/2022] Open
Abstract
The malaria parasite exports hundreds of proteins into its host cell. The majority of exported proteins contain a Host-Targeting motif (also known as a Plasmodium export element) that directs them for export. Prior to export, the Host-Targeting motif is cleaved by the endoplasmic reticulum-resident protease Plasmepsin V and the newly generated N-terminus is N-α-acetylated by an unidentified enzyme. The cleaved, N-α-acetylated protein is trafficked to the parasitophorous vacuole, where it is translocated across the vacuole membrane. It is clear that cleavage and N-α-acetylation of the Host-Targeting motif occur at the endoplasmic reticulum, and it has been proposed that Host-Targeting motif cleavage and N-α-acetylation occur either on the luminal or cytosolic side of the endoplasmic reticulum membrane. Here, we use self-associating ‘split’ fragments of GFP to determine the topology of Plasmepsin V in the endoplasmic reticulum membrane; we show that the catalytic protease domain of Plasmepsin V faces the endoplasmic reticulum lumen. These data support a model in which the Host-Targeting motif is cleaved and N-α-acetylated in the endoplasmic reticulum lumen. Furthermore, these findings suggest that cytosolic N-α-acetyltransferases are unlikely to be candidates for the N-α-acetyltransferase of Host-Targeting motif-containing exported proteins.
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Affiliation(s)
- Sarah J. Tarr
- Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck and University College London, London, United Kingdom
| | - Andrew R. Osborne
- Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck and University College London, London, United Kingdom
- * E-mail:
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Gazdik M, O'Neill MT, Lopaticki S, Lowes KN, Smith BJ, Cowman AF, Boddey JA, Sleebs BE. The effect of N-methylation on transition state mimetic inhibitors of the Plasmodium protease, plasmepsin V. MEDCHEMCOMM 2015. [DOI: 10.1039/c4md00409d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An N-methylation strategy has been applied to transition state mimetics that are potent inhibitors of plasmepsin V to improve their physical characteristics and their ability to reduce the viability of Plasmodium parasites in culture.
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Affiliation(s)
- Michelle Gazdik
- The Walter and Eliza Hall Institute of Medical Research
- Parkville
- Australia
- Department of Medical Biology
- The University of Melbourne
| | - Matthew T. O'Neill
- The Walter and Eliza Hall Institute of Medical Research
- Parkville
- Australia
- Department of Medical Biology
- The University of Melbourne
| | - Sash Lopaticki
- The Walter and Eliza Hall Institute of Medical Research
- Parkville
- Australia
- Department of Medical Biology
- The University of Melbourne
| | - Kym N. Lowes
- The Walter and Eliza Hall Institute of Medical Research
- Parkville
- Australia
- Department of Medical Biology
- The University of Melbourne
| | | | - Alan F. Cowman
- The Walter and Eliza Hall Institute of Medical Research
- Parkville
- Australia
- Department of Medical Biology
- The University of Melbourne
| | - Justin A. Boddey
- The Walter and Eliza Hall Institute of Medical Research
- Parkville
- Australia
- Department of Medical Biology
- The University of Melbourne
| | - Brad E. Sleebs
- The Walter and Eliza Hall Institute of Medical Research
- Parkville
- Australia
- Department of Medical Biology
- The University of Melbourne
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40
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Xiao H, Bryksa BC, Bhaumik P, Gustchina A, Kiso Y, Yao SQ, Wlodawer A, Yada RY. The zymogen of plasmepsin V from Plasmodium falciparum is enzymatically active. Mol Biochem Parasitol 2014; 197:56-63. [PMID: 25447707 PMCID: PMC6310130 DOI: 10.1016/j.molbiopara.2014.10.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 10/15/2014] [Accepted: 10/16/2014] [Indexed: 10/24/2022]
Abstract
Plasmepsin V, a membrane-bound aspartic protease present in Plasmodium falciparum, is involved in the export of malaria parasite effector proteins into host erythrocytes and therefore is a potential target for antimalarial drug development. The present study reports the bacterial recombinant expression and initial characterization of zymogenic and mature plasmepsin V. A 484-residue truncated form of proplasmepsin (Glu37-Asn521) was fused to a fragment of thioredoxin and expressed as inclusion bodies. Refolding conditions were optimized and zymogen was processed into a mature form via cleavage at the Asn80-Ala81 peptide bond. Mature plasmepsin V exhibited a pH optimum of 5.5-7.0 with Km and kcat of 4.6 μM and 0.24s(-1), respectively, at pH 6.0 using the substrate DABCYL-LNKRLLHETQ-E(EDANS). Furthermore, the prosegment of proplasmepsin V was shown to be nonessential for refolding and inhibition. Unexpectedly, unprocessed proplasmepsin V was enzymatically active with slightly reduced substrate affinity (∼ 2-fold), and similar pH optimum as well as turnover compared to the mature form. Both zymogenic and mature plasmepsin V were partially inhibited by pepstatin A as well as several KNI aspartic protease inhibitors while certain metals strongly inhibited activity. Overall, the present study provides the first report on the nonessentiality of the prosegment for plasmepsin V folding and activity, and therefore, subsequent characterization of its structure-function relationships of both zymogen and mature forms in the development of novel inhibitors with potential antimalarial activities is warranted.
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Affiliation(s)
- Huogen Xiao
- Department of Food Science, University of Guelph, 50 Stone Road East, Guelph, ON, Canada N1G2W1
| | - Brian C Bryksa
- Department of Food Science, University of Guelph, 50 Stone Road East, Guelph, ON, Canada N1G2W1
| | - Prasenjit Bhaumik
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Alla Gustchina
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Yoshiaki Kiso
- Laboratory of Peptide Science, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829, Japan
| | - Shao Q Yao
- Department of Chemistry, National University of Singapore, 3 Science Drive, Singapore 117543, Singapore
| | - Alexander Wlodawer
- Protein Structure Section, Macromolecular Crystallography Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Rickey Y Yada
- Department of Food Science, University of Guelph, 50 Stone Road East, Guelph, ON, Canada N1G2W1; Faculty of Land and Food Systems, University of British Columbia 248-2357 Main Mall Vancouver, BC V6T 1Z4.
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41
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Sleebs BE, Gazdik M, O'Neill MT, Rajasekaran P, Lopaticki S, Lackovic K, Lowes K, Smith BJ, Cowman AF, Boddey JA. Transition state mimetics of the Plasmodium export element are potent inhibitors of Plasmepsin V from P. falciparum and P. vivax. J Med Chem 2014; 57:7644-62. [PMID: 25167370 DOI: 10.1021/jm500797g] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Following erythrocyte invasion, malaria parasites export a catalogue of remodeling proteins into the infected cell that enable parasite development in the human host. Export is dependent on the activity of the aspartyl protease, plasmepsin V (PMV), which cleaves proteins within the Plasmodium export element (PEXEL; RxL↓xE/Q/D) in the parasite's endoplasmic reticulum. Here, we generated transition state mimetics of the native PEXEL substrate that potently inhibit PMV isolated from Plasmodium falciparum and Plasmodium vivax. Through optimization, we identified that the activity of the mimetics was completely dependent on the presence of P1 Leu and P3 Arg. Treatment of P. falciparum-infected erythrocytes with a set of optimized mimetics impaired PEXEL processing and killed the parasites. The striking effect of the compounds provides a clearer understanding of the accessibility of the PMV active site and reaffirms the enzyme as an attractive target for the design of future antimalarials.
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Affiliation(s)
- Brad E Sleebs
- The Walter and Eliza Hall Institute of Medical Research , 1G Royal Parade, Parkville 3052, Victoria, Australia
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42
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Prajapati SK, Culleton R, Singh OP. Protein trafficking in Plasmodium falciparum-infected red cells and impact of the expansion of exported protein families. Parasitology 2014; 141:1-11. [PMID: 25076418 DOI: 10.1017/s0031182014000948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARY Erythrocytes are extensively remodelled by the malaria parasite following invasion of the cell. Plasmodium falciparum encodes numerous virulence-associated and host-cell remodelling proteins that are trafficked to the cytoplasm, the cell membrane and the surface of the infected erythrocyte. The export of soluble proteins relies on a sequence directing entry into the secretory pathways in addition to an export signal. The export signal consisting of five amino acids is termed the Plasmodium export element (PEXEL) or the vacuole transport signal (VTS). Genome mining studies have revealed that PEXEL/VTS carrying protein families have expanded dramatically in P. falciparum compared with other malaria parasite species, possibly due to lineage-specific expansion linked to the unique requirements of P. falciparum for host-cell remodelling. The functional characterization of such genes and gene families may reveal potential drug targets that could inhibit protein trafficking in infected erythrocytes. This review highlights some of the recent advances and key knowledge gaps in protein trafficking pathways in P. falciparum-infected red cells and speculates on the impact of exported gene families in the trafficking pathway.
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Affiliation(s)
- Surendra K Prajapati
- Molecular Biology Division,National Institute of Malaria Research,New Delhi,India
| | - Richard Culleton
- Malaria Unit,Institute for Tropical Medicine (NEKKEN), Nagasaki University,Nagasaki,Japan
| | - Om P Singh
- Molecular Biology Division,National Institute of Malaria Research,New Delhi,India
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43
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Inhibition of Plasmepsin V activity demonstrates its essential role in protein export, PfEMP1 display, and survival of malaria parasites. PLoS Biol 2014; 12:e1001897. [PMID: 24983235 PMCID: PMC4077696 DOI: 10.1371/journal.pbio.1001897] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 05/22/2014] [Indexed: 11/19/2022] Open
Abstract
The malaria parasite Plasmodium falciparum exports several hundred proteins into the infected erythrocyte that are involved in cellular remodeling and severe virulence. The export mechanism involves the Plasmodium export element (PEXEL), which is a cleavage site for the parasite protease, Plasmepsin V (PMV). The PMV gene is refractory to deletion, suggesting it is essential, but definitive proof is lacking. Here, we generated a PEXEL-mimetic inhibitor that potently blocks the activity of PMV isolated from P. falciparum and Plasmodium vivax. Assessment of PMV activity in P. falciparum revealed PEXEL cleavage occurs cotranslationaly, similar to signal peptidase. Treatment of P. falciparum-infected erythrocytes with the inhibitor caused dose-dependent inhibition of PEXEL processing as well as protein export, including impaired display of the major virulence adhesin, PfEMP1, on the erythrocyte surface, and cytoadherence. The inhibitor killed parasites at the trophozoite stage and knockdown of PMV enhanced sensitivity to the inhibitor, while overexpression of PMV increased resistance. This provides the first direct evidence that PMV activity is essential for protein export in Plasmodium spp. and for parasite survival in human erythrocytes and validates PMV as an antimalarial drug target.
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44
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Mastan BS, Kumari A, Gupta D, Mishra S, Kumar KA. Gene disruption reveals a dispensable role for plasmepsin VII in the Plasmodium berghei life cycle. Mol Biochem Parasitol 2014; 195:10-3. [PMID: 24893340 DOI: 10.1016/j.molbiopara.2014.05.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 05/14/2014] [Accepted: 05/22/2014] [Indexed: 12/20/2022]
Abstract
Plasmepsins (PM), aspartic proteases of Plasmodium, comprises a family of ten proteins that perform critical functions in Plasmodium life cycle. Except VII and VIII, functions of the remaining plasmepsin members have been well characterized. Here, we have generated a mutant parasite lacking PM VII in Plasmodium berghei using reverse genetics approach. Systematic comparison of growth kinetics and infection in both mosquito and vertebrate host revealed that PM VII depleted mutants exhibited no defects in development and progressed normally throughout the parasite life cycle. These studies suggest a dispensable role for PM VII in Plasmodium berghei life cycle.
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Affiliation(s)
- Babu S Mastan
- Department of Animal Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Anchala Kumari
- Bioinformatics Laboratory, SCB Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, 110 067 New Delhi, India
| | - Dinesh Gupta
- Bioinformatics Laboratory, SCB Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, 110 067 New Delhi, India
| | - Satish Mishra
- Division of Parasitology, CSIR-Central Drug Research Institute, Lucknow, India
| | - Kota Arun Kumar
- Department of Animal Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, India.
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45
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Optimization of Protease Extraction from Horse Mango (Mangifera foetidaLour) Kernels by a Response Surface Methodology. Biosci Biotechnol Biochem 2014; 76:1438-44. [DOI: 10.1271/bbb.120073] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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46
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Krai P, Dalal S, Klemba M. Evidence for a Golgi-to-endosome protein sorting pathway in Plasmodium falciparum. PLoS One 2014; 9:e89771. [PMID: 24587025 PMCID: PMC3934947 DOI: 10.1371/journal.pone.0089771] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 01/24/2014] [Indexed: 12/20/2022] Open
Abstract
During the asexual intraerythrocytic stage, the malaria parasite Plasmodium falciparum must traffic newly-synthesized proteins to a broad array of destinations within and beyond the parasite's plasma membrane. In this study, we have localized two well-conserved protein components of eukaryotic endosomes, the retromer complex and the small GTPase Rab7, to define a previously-undescribed endosomal compartment in P. falciparum. Retromer and Rab7 co-localized to a small number of punctate structures within parasites. These structures, which we refer to as endosomes, lie in close proximity to the Golgi apparatus and, like the Golgi apparatus, are inherited by daughter merozoites. However, the endosome is clearly distinct from the Golgi apparatus as neither retromer nor Rab7 redistributed to the endoplasmic reticulum upon brefeldin A treatment. Nascent rhoptries (specialized secretory organelles required for invasion) developed adjacent to endosomes, an observation that suggests a role for the endosome in rhoptry biogenesis. A P. falciparum homolog of the sortilin family of protein sorting receptors (PfSortilin) was localized to the Golgi apparatus. Together, these results elaborate a putative Golgi-to-endosome protein sorting pathway in asexual blood stage parasites and suggest that one role of retromer is to mediate the retrograde transport of PfSortilin from the endosome to the Golgi apparatus.
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Affiliation(s)
- Priscilla Krai
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Seema Dalal
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Michael Klemba
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
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47
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Elsworth B, Crabb BS, Gilson PR. Protein export in malaria parasites: an update. Cell Microbiol 2014; 16:355-63. [PMID: 24418476 DOI: 10.1111/cmi.12261] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 01/04/2014] [Accepted: 01/06/2014] [Indexed: 11/30/2022]
Abstract
Symptomatic malaria is caused by the infection of human red blood cells (RBCs) with Plasmodium parasites. The RBC is a peculiar environment for parasites to thrive in as they lack many of the normal cellular processes and resources present in other cells. Because of this, Plasmodium spp. have adapted to extensively remodel the host cell through the export of hundreds of proteins that have a range of functions, the best known of which are virulence-associated. Many exported parasite proteins are themselves involved in generating a novel trafficking system in the RBC that further promotes export. In this review we provide an overview of the parasite synthesized export machinery as well as recent developments in how different classes of exported proteins are recognized by this machinery.
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Affiliation(s)
- Brendan Elsworth
- Burnet Institute, 85 Commercial Road, Melbourne, Vic., 3004, Australia; Monash University, Clayton, Vic., Australia
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48
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Rawat M, Vijay S, Gupta Y, Tiwari PK, Sharma A. Imperfect duplicate insertions type of mutations in plasmepsin V modulates binding properties of PEXEL motifs of export proteins in Indian Plasmodium vivax. PLoS One 2013; 8:e60077. [PMID: 23555891 PMCID: PMC3612065 DOI: 10.1371/journal.pone.0060077] [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: 12/06/2012] [Accepted: 02/21/2013] [Indexed: 01/12/2023] Open
Abstract
Introduction Plasmepsin V (PM-V) have functionally conserved orthologues across the Plasmodium genus who's binding and antigenic processing at the PEXEL motifs for export about 200–300 essential proteins is important for the virulence and viability of the causative Plasmodium species. This study was undertaken to determine P. vivax plasmepsin V Ind (PvPM-V-Ind) PEXEL motif export pathway for pathogenicity-related proteins/antigens export thereby altering plasmodium exportome during erythrocytic stages. Method We identify and characterize Plasmodium vivax plasmepsin-V-Ind (mutant) gene by cloning, sequence analysis, in silico bioinformatic protocols and structural modeling predictions based on docking studies on binding capacity with PEXEL motifs processing in terms of binding and accessibility of export proteins. Results Cloning and sequence analysis for genetic diversity demonstrates PvPM-V-Ind (mutant) gene is highly conserved among all isolates from different geographical regions of India. Imperfect duplicate insertion types of mutations (SVSE from 246–249 AA and SLSE from 266–269 AA) were identified among all Indian isolates in comparison to P.vivax Sal-1 (PvPM-V-Sal 1) isolate. In silico bioinformatics interaction studies of PEXEL peptide and active enzyme reveal that PvPM-V-Ind (mutant) is only active in endoplasmic reticulum lumen and membrane embedding is essential for activation of plasmepsin V. Structural modeling predictions based on docking studies with PEXEL motif show significant variation in substrate protein binding of these imperfect mutations with data mined PEXEL sequences. The predicted variation in the docking score and interacting amino acids of PvPM-V-Ind (mutant) proteins with PEXEL and lopinavir suggests a modulation in the activity of PvPM-V in terms of binding and accessibility at these sites. Conclusion/Significance Our functional modeled validation of PvPM-V-Ind (mutant) imperfect duplicate insertions with data mined PEXEL sequences leading to altered binding and substrate accessibility of the enzyme makes it a plausible target to investigate export mechanisms for in silico virtual screening and novel pharmacophore designing.
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Affiliation(s)
- Manmeet Rawat
- Protein Biochemistry and Structural Biology Division, National Institute of Malaria Research (ICMR), Dwarka, New Delhi, India
- Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America
| | - Sonam Vijay
- Protein Biochemistry and Structural Biology Division, National Institute of Malaria Research (ICMR), Dwarka, New Delhi, India
| | - Yash Gupta
- Department of Microbiology and Molecular Biology, National JALMA Institute for Leprosy and Other Mycobacterial Diseases (ICMR), Agra, Uttar Pradesh, India
| | - Pramod Kumar Tiwari
- Centre for Genomics, Molecular and Human Genetics, Jiwaji University, Gwalior, Madhya Pradesh, India
| | - Arun Sharma
- Protein Biochemistry and Structural Biology Division, National Institute of Malaria Research (ICMR), Dwarka, New Delhi, India
- * E-mail:
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49
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Boddey JA, Carvalho TG, Hodder AN, Sargeant TJ, Sleebs BE, Marapana D, Lopaticki S, Nebl T, Cowman AF. Role of Plasmepsin V in Export of Diverse Protein Families from the
Plasmodium falciparum
Exportome. Traffic 2013; 14:532-50. [DOI: 10.1111/tra.12053] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 01/29/2013] [Accepted: 02/06/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Justin A. Boddey
- Division of Infection and Immunity The Walter and Eliza Hall Institute of Medical Research Parkville Victoria 3052 Australia
- Department of Medical Biology University of Melbourne Parkville Victoria 3052 Australia
| | - Teresa G. Carvalho
- Division of Infection and Immunity The Walter and Eliza Hall Institute of Medical Research Parkville Victoria 3052 Australia
| | - Anthony N. Hodder
- Division of Infection and Immunity The Walter and Eliza Hall Institute of Medical Research Parkville Victoria 3052 Australia
- Department of Medical Biology University of Melbourne Parkville Victoria 3052 Australia
| | - Tobias J. Sargeant
- Division of Infection and Immunity The Walter and Eliza Hall Institute of Medical Research Parkville Victoria 3052 Australia
| | - Brad E. Sleebs
- Division of Infection and Immunity The Walter and Eliza Hall Institute of Medical Research Parkville Victoria 3052 Australia
| | - Danushka Marapana
- Division of Infection and Immunity The Walter and Eliza Hall Institute of Medical Research Parkville Victoria 3052 Australia
| | - Sash Lopaticki
- Division of Infection and Immunity The Walter and Eliza Hall Institute of Medical Research Parkville Victoria 3052 Australia
| | - Thomas Nebl
- Division of Infection and Immunity The Walter and Eliza Hall Institute of Medical Research Parkville Victoria 3052 Australia
| | - Alan F. Cowman
- Division of Infection and Immunity The Walter and Eliza Hall Institute of Medical Research Parkville Victoria 3052 Australia
- Department of Medical Biology University of Melbourne Parkville Victoria 3052 Australia
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50
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Bullen HE, Crabb BS, Gilson PR. Recent insights into the export of PEXEL/HTS-motif containing proteins in Plasmodium parasites. Curr Opin Microbiol 2012; 15:699-704. [DOI: 10.1016/j.mib.2012.09.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 09/22/2012] [Accepted: 09/25/2012] [Indexed: 10/27/2022]
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