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Mohammad K, Appasani SL, Ito M, Percopo C, Desai SA. Optimized plasmid loading of human erythrocytes for Plasmodium falciparum DNA transfections. Int J Parasitol 2024:S0020-7519(24)00081-X. [PMID: 38719176 DOI: 10.1016/j.ijpara.2024.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 03/06/2024] [Accepted: 04/30/2024] [Indexed: 05/16/2024]
Abstract
In vitro modification of Plasmodium falciparum genes is the cornerstone of basic and translational malaria research. Achieved through DNA transfection, these modifications may entail altering protein sequence or abundance. Such experiments are critical for defining the molecular mechanisms of key parasite phenotypes and for validation of drug and vaccine targets. Despite its importance, successful transfection remains difficult and is a resource-intensive, rate-limiting step in P. falciparum research. Here, we report that inefficient loading of plasmid into erythrocytes limits transfection efficacy with commonly used electroporation methods. As these methods also require expensive instrumentation and consumables that are not broadly available, we explored a simpler method based on plasmid loading through hypotonic lysis and resealing of erythrocytes. We used parasite expression of a sensitive NanoLuc reporter for rapid evaluation and optimization of each step. Hypotonic buffer composition, resealing buffer volume and composition, and subsequent incubation affected plasmid retention and successful transfection. While ATP was critical for erythrocyte resealing, addition of Ca++ or glutathione did not improve transfection efficiency, with increasing Ca++ concentrations proving detrimental to outcomes. Compared with either the standard electroporation method or a previously reported hypotonic loading protocol, the optimized method yields greater plasmid loading and higher expression of the NanoLuc reporter 48 h after transfection. It also produced significantly faster outgrowth of parasites in transfections utilizing either episomal expression or CRISPR-Cas9 mediated integration. This new method produces higher P. falciparum transfection efficiency, reduces resource requirements and should accelerate molecular studies of malaria drug and vaccine targets.
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Affiliation(s)
- Kashif Mohammad
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Sri Lalana Appasani
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Mai Ito
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Caroline Percopo
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Sanjay A Desai
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA.
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2
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Gonçalves AF, Lima-Pinheiro A, Teixeira M, Cassiano GC, Cravo P, Ferreira PE. Mutation in the 26S proteasome regulatory subunit rpn2 gene in Plasmodium falciparum confers resistance to artemisinin. Front Cell Infect Microbiol 2024; 14:1342856. [PMID: 38404287 PMCID: PMC10884193 DOI: 10.3389/fcimb.2024.1342856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/22/2024] [Indexed: 02/27/2024] Open
Abstract
Introduction Malaria parasites increasingly develop resistance to all drugs available in the market, hampering the goal of reducing malaria burden. Methods Herein, we evaluated the impact of a single-nucleotide variant, E738K, present in the 26S proteasome regulatory subunit rpn2 gene, identified in Plasmodium chabaudi resistant parasites. Plasmids carrying a functional rpn2 interspecies chimeric gene with 5' recombination region from P. falciparum and 3' from P. chabaudi were constructed and transfected into Dd2 P. falciparum parasites. Results and discussion The 738K variant parasite line presented increased parasite survival when subjected to dihydroartemisinin (DHA), as well as increased chymotrypsin-like activity and decreased accumulation of polyubiquitinated proteins. We thus conclude that the ubiquitin-proteasome pathway, including the 738K variant, play an important role in parasite response to DHA, being the first report of a mutation in a potential DHA drug target enhancing parasite survival and contributing to a significant advance in the understanding the biology of artemisinin resistance.
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Affiliation(s)
- Adriana F. Gonçalves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- Life and Health Sciences Research Institute (ICVS)/ Biomaterials, Biodegradables and Biomimetics Research Group (3B's)-PT Government Associate Laboratory, Braga, Portugal
| | - Ana Lima-Pinheiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- Life and Health Sciences Research Institute (ICVS)/ Biomaterials, Biodegradables and Biomimetics Research Group (3B's)-PT Government Associate Laboratory, Braga, Portugal
| | - Miguel Teixeira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- Life and Health Sciences Research Institute (ICVS)/ Biomaterials, Biodegradables and Biomimetics Research Group (3B's)-PT Government Associate Laboratory, Braga, Portugal
- Department of Protection of Specific Crops, InnovPlantProtect Collaborative Laboratory, Elvas, Portugal
| | - Gustavo Capatti Cassiano
- Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation Towards Global Health (LA-REAL), Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa (UNL), Lisbon, Portugal
| | - Pedro Cravo
- Global Health and Tropical Medicine (GHTM), Associate Laboratory in Translation and Innovation Towards Global Health (LA-REAL), Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa (UNL), Lisbon, Portugal
| | - Pedro E. Ferreira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- Life and Health Sciences Research Institute (ICVS)/ Biomaterials, Biodegradables and Biomimetics Research Group (3B's)-PT Government Associate Laboratory, Braga, Portugal
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3
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Gabriela M, Barnes CBG, Leong D, Sleebs BE, Schneider MP, Littler DR, Crabb BS, de Koning‐Ward TF, Gilson PR. Sequence elements within the PEXEL motif and its downstream region modulate PTEX-dependent protein export in Plasmodium falciparum. Traffic 2024; 25:e12922. [PMID: 37926971 PMCID: PMC10952997 DOI: 10.1111/tra.12922] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 08/23/2023] [Accepted: 10/15/2023] [Indexed: 11/07/2023]
Abstract
The parasite Plasmodium falciparum causes the most severe form of malaria and to invade and replicate in red blood cells (RBCs), it exports hundreds of proteins across the encasing parasitophorous vacuole membrane (PVM) into this host cell. The exported proteins help modify the RBC to support rapid parasite growth and avoidance of the human immune system. Most exported proteins possess a conserved Plasmodium export element (PEXEL) motif with the consensus RxLxE/D/Q amino acid sequence, which acts as a proteolytic cleavage recognition site within the parasite's endoplasmic reticulum (ER). Cleavage occurs after the P1 L residue and is thought to help release the protein from the ER so it can be putatively escorted by the HSP101 chaperone to the parasitophorous vacuole space surrounding the intraerythrocytic parasite. HSP101 and its cargo are then thought to assemble with the rest of a Plasmodium translocon for exported proteins (PTEX) complex, that then recognises the xE/D/Q capped N-terminus of the exported protein and translocates it across the vacuole membrane into the RBC compartment. Here, we present evidence that supports a dual role for the PEXEL's conserved P2 ' position E/Q/D residue, first, for plasmepsin V cleavage in the ER, and second, for efficient PTEX mediated export across the PVM into the RBC. We also present evidence that the downstream 'spacer' region separating the PEXEL motif from the folded functional region of the exported protein controls cargo interaction with PTEX as well. The spacer must be of a sufficient length and permissive amino acid composition to engage the HSP101 unfoldase component of PTEX to be efficiently translocated into the RBC compartment.
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Affiliation(s)
- Mikha Gabriela
- Malaria Virulence and Drug Discovery GroupBurnet InstituteMelbourneVictoriaAustralia
- School of MedicineDeakin UniversityGeelongVictoriaAustralia
| | - Claudia B. G. Barnes
- Malaria Virulence and Drug Discovery GroupBurnet InstituteMelbourneVictoriaAustralia
| | - Dickson Leong
- Malaria Virulence and Drug Discovery GroupBurnet InstituteMelbourneVictoriaAustralia
| | - Brad E. Sleebs
- The Walter and Eliza Hall Institute of Medical ResearchParkvilleVictoriaAustralia
- Department of Medical BiologyThe University of MelbourneParkvilleVictoriaAustralia
| | | | - Dene R. Littler
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery InstituteMonash UniversityClaytonVictoriaAustralia
| | - Brendan S. Crabb
- Malaria Virulence and Drug Discovery GroupBurnet InstituteMelbourneVictoriaAustralia
- Department of Medical BiologyThe University of MelbourneParkvilleVictoriaAustralia
- Department of Microbiology and ImmunologyUniversity of MelbourneParkvilleVictoriaAustralia
- Department of ImmunologyMonash UniversityMelbourneVictoriaAustralia
| | - Tania F. de Koning‐Ward
- School of MedicineDeakin UniversityGeelongVictoriaAustralia
- Institute for Mental and Physical Health and Clinical Translation (IMPACT)Deakin UniversityGeelongVictoriaAustralia
| | - Paul R. Gilson
- Malaria Virulence and Drug Discovery GroupBurnet InstituteMelbourneVictoriaAustralia
- Department of Microbiology and ImmunologyUniversity of MelbourneParkvilleVictoriaAustralia
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4
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Cubillos EFG, Snebergerova P, Borsodi S, Reichensdorferova D, Levytska V, Asada M, Sojka D, Jalovecka M. Establishment of a stable transfection and gene targeting system in Babesia divergens. Front Cell Infect Microbiol 2023; 13:1278041. [PMID: 38156314 PMCID: PMC10753763 DOI: 10.3389/fcimb.2023.1278041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 11/29/2023] [Indexed: 12/30/2023] Open
Abstract
Babesia divergens is an emerging tick-borne pathogen considered as the principal causative agent of bovine babesiosis in Europe with a notable zoonotic risk to human health. Despite its increasing impact, considerable gaps persist in our understanding of the molecular interactions between this parasite and its hosts. In this study, we address the current limitation of functional genomic tools in B. divergens and introduce a stable transfection system specific to this parasite. We define the parameters for a drug selection system hdhfr-WR99210 and evaluate different transfection protocols for highly efficient generation of transgenic parasites expressing GFP. We proved that plasmid delivery into bovine erythrocytes prior to their infection is the most optimal transfection approach for B. divergens, providing novel evidence of Babesia parasites' ability to spontaneously uptake external DNA from erythrocytes cytoplasm. Furthermore, we validated the bidirectional and symmetrical activity of ef-tgtp promoter, enabling simultaneous expression of external genes. Lastly, we generated a B. divergens knockout line by targeting a 6-cys-e gene locus. The observed dispensability of this gene in intraerythrocytic parasite development makes it a suitable recipient locus for further transgenic application. The platform for genetic manipulations presented herein serves as the initial step towards developing advanced functional genomic tools enabling the discovery of B. divergens molecules involved in host-vector-pathogen interactions.
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Affiliation(s)
- Eliana F. G. Cubillos
- Faculty of Science, University of South Bohemia in Ceske Budejovice, Ceske Budejovice, Czechia
| | - Pavla Snebergerova
- Faculty of Science, University of South Bohemia in Ceske Budejovice, Ceske Budejovice, Czechia
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czechia
| | - Sarka Borsodi
- Faculty of Science, University of South Bohemia in Ceske Budejovice, Ceske Budejovice, Czechia
| | | | - Viktoriya Levytska
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czechia
| | - Masahito Asada
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Obihiro, Japan
| | - Daniel Sojka
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czechia
| | - Marie Jalovecka
- Faculty of Science, University of South Bohemia in Ceske Budejovice, Ceske Budejovice, Czechia
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czechia
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5
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Lima C, Verdaguer IB, Wunderlich G, Katzin AM, Crabb BS, Gilson PR, Azevedo MF. Conditional expression of NanoLuc luciferase through a multimodular system offers rapid detection of antimalarial drug activity. Exp Parasitol 2023; 254:108620. [PMID: 37716462 DOI: 10.1016/j.exppara.2023.108620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 09/06/2023] [Accepted: 09/12/2023] [Indexed: 09/18/2023]
Abstract
Conditional gene expression is a powerful tool to investigate putative vaccine and drug targets, especially in a haploid organism such as Plasmodium falciparum. Inducible systems based on regulation of either transcription, translation, protein or mRNA stability, among others, allow switching on an off the expression of any desired gene causing specific gain or loss of function phenotypes. However, those systems can be cumbersome involving the construction of large plasmids and generation of multiple transgenic parasite lines. In addition, the dynamic range of regulation achieved is not predictable for each individual gene and can be insufficient to generate detectable phenotypes when the genes of interest are silenced. Here, we combined up to three distinct inducible systems to regulate the expression of a single gene. Expression of the reporter NanoLuc luciferase was regulated over 40-fold, which correlates to the regulation achieved by each individual system multiplied by each other. We applied the conditionally expressed NanoLuc to evaluate the effect of fast-acting antimalarials such as chloroquine and artesunate as well as of slower-acting ones such as atovaquone. The conditionally expressed reporter allowed faster and more reliable detection of toxicity to the parasite, which correlated to the expected action of each compound. Bioluminescence achieved by the expression of this inducible highly sensitive reporter is therefore a promising tool to investigate the temporal effect of potential new antimalarials. This single plasmid combination system might also prove useful to achieve sufficient regulation of genes of interest to produce loss-of-function phenotypes.
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Affiliation(s)
- Caroline Lima
- Federal University of Sao Paulo, Santos, Sao Paulo, Brazil
| | - Ignasi B Verdaguer
- Departamento de Parasitologia, Instituto de Ciência Biomédicas, Universidade de São Paulo, Avenida Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-900, Brazil
| | - Gerhard Wunderlich
- Departamento de Parasitologia, Instituto de Ciência Biomédicas, Universidade de São Paulo, Avenida Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-900, Brazil
| | - Alejandro M Katzin
- Departamento de Parasitologia, Instituto de Ciência Biomédicas, Universidade de São Paulo, Avenida Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-900, Brazil
| | - Brendan S Crabb
- Burnet Institute, Melbourne, VIC, 3004, Australia; University of Melbourne, VIC, 3052, Australia; Monash University, Melbourne, VIC, 3004, Australia
| | - Paul R Gilson
- Burnet Institute, Melbourne, VIC, 3004, Australia; University of Melbourne, VIC, 3052, Australia
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6
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Barnes CBG, Dans MG, Jonsdottir TK, Crabb BS, Gilson PR. PfATP4 inhibitors in the Medicines for Malaria Venture Malaria Box and Pathogen Box block the schizont-to-ring transition by inhibiting egress rather than invasion. Front Cell Infect Microbiol 2022; 12:1060202. [PMID: 36530423 PMCID: PMC9747762 DOI: 10.3389/fcimb.2022.1060202] [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: 10/03/2022] [Accepted: 11/15/2022] [Indexed: 12/05/2022] Open
Abstract
The cation efflux pump Plasmodium falciparum ATPase 4 (PfATP4) maintains Na+ homeostasis in malaria parasites and has been implicated in the mechanism of action of many structurally diverse antimalarial agents, including >7% of the antimalarial compounds in the Medicines for Malaria Venture's 'Malaria Box' and 'Pathogen Box'. Recent screens of the 'Malaria Box' and 'Pathogen Box' revealed that many PfATP4 inhibitors prevent parasites from exiting their host red blood cell (egress) or entering new host cells (invasion), suggesting that these compounds may have additional molecular targets involved in egress or invasion. Here, we demonstrate that five PfATP4 inhibitors reduce egress but not invasion. These compounds appear to inhibit egress by blocking the activation of protein kinase G, an enzyme that, once stimulated, rapidly activates parasite egress. We establish a direct link between egress and PfATP4 function by showing that the inhibition of egress is attenuated in a Na+-depleted environment and in parasites with a mutation in pfatp4. Finally, we show that PfATP4 inhibitors induce host cell lysis when administered prior to the completion of parasite replication. Since host cell lysis mimics egress but is not followed by invasion, this phenomenon likely explains why several PfATP4 inhibitors were previously classified as invasion inhibitors. Collectively, our results confirm that PfATP4-mediated Na+ efflux is critical to the regulation of parasite egress.
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Affiliation(s)
- Claudia B. G. Barnes
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia,Department of Medicine, The University of Melbourne, Melbourne, VIC, Australia
| | - Madeline G. Dans
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia,School of Medicine, Deakin University, Geelong, VIC, Australia
| | - Thorey K. Jonsdottir
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia,Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
| | - Brendan S. Crabb
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia,Department of Microbiology and Immunology, The University of Melbourne, Parkville, VIC, Australia,Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
| | - Paul R. Gilson
- Life Sciences, Burnet Institute, Melbourne, VIC, Australia,Department of Microbiology and Immunology, The University of Melbourne, Parkville, VIC, Australia,*Correspondence: Paul R. Gilson,
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7
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Chakrabarti M, Garg S, Munjal A, Karan S, Pati S, Garg LC, Singh S. A Fast-Track Phenotypic Characterization of Plasmodium falciparum Vaccine Antigens through Lyse-Reseal Erythrocytes Mediated Delivery (LyRED) of RNA Interference for Targeted Translational Repression. Methods Mol Biol 2022; 2410:539-553. [PMID: 34914066 DOI: 10.1007/978-1-0716-1884-4_27] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The minimal success of the malaria vaccine with available antigens indicates the need for intensive and accelerated research to identify and characterize new antigens that confer protection against infection, clinical manifestation, and even malaria transmission. Further, the genetic manipulation tools to characterize such antigens are very time-consuming and laborious due to the very low efficiency of transfection in the malaria parasite. Here, we report a human miRNA-mediated translational repression of antigens in Plasmodium falciparum as a fast-track method for understanding and validating their function. In this method, candidate miRNAs are designed based on favorable hybridization energy against a parasite gene, and miRNA mimics are delivered to the parasite by loading them as cargo in the erythrocytes by simple lyse-reseal method. Incubation of the miRNA loaded erythrocytes with purified mature trophozoites or schizonts results in the loaded erythrocytes' infection. The miRNA mimics are translocated to parasites, and the effect of miRNA-mediated translation repression can be monitored within 48-72 h post-invasion. Unlike other transfection based methods, this method is fast, reproducible, and robust. We call this method as lyse-reseal erythrocytes for delivery (LyRED) of miRNA, which is a rapid and straight-forward method providing an efficient alternative to the existing genetic tools for P. falciparum to characterize the function of antigens or genes. The identification of crucial antigens from the different stages of the Plasmodium falciparum life cycle by the miRNA targeting approach can fuel the development of efficacious subunit vaccines against malaria.
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Affiliation(s)
- Malabika Chakrabarti
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Swati Garg
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Akshay Munjal
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Sweta Karan
- Gene Regulation Laboratory, National Institute of Immunology, New Delhi, India
| | - Soumya Pati
- Department of Life Science, School of Natural Sciences, Shiv Nadar University, Gautam Buddh Nagar, Uttar Pradesh, India
| | - Lalit C Garg
- Gene Regulation Laboratory, National Institute of Immunology, New Delhi, India.
| | - Shailja Singh
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India.
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8
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Ressurreição M, Moon RW, Baker DA, van Ooij C. Synchronisation of Plasmodium falciparum and P. knowlesi In Vitro Cultures Using a Highly Specific Protein Kinase Inhibitor. Methods Mol Biol 2022; 2470:101-120. [PMID: 35881342 DOI: 10.1007/978-1-0716-2189-9_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Synchronisation of Plasmodium cultures is essential to investigate the complexities of time-dependent events associated with the asexual blood stage of the malaria parasite life cycle. Here we describe a procedure using ML10, a highly specific inhibitor of the parasite cyclic GMP-dependent protein kinase (PKG), to attain high synchronicity of Plasmodium falciparum and P. knowlesi asexual blood-stage cultures and to obtain high levels of arrested mature schizonts as well as viable released merozoites. Additionally, we describe how to use ML10 to improve the transfection efficiency of P. falciparum parasites and also how to derive the half maximal effective concentration (EC50) of ML10 in other P. falciparum laboratory lines and clinical isolates.
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Affiliation(s)
- Margarida Ressurreição
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Robert William Moon
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - David Andrew Baker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Christiaan van Ooij
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
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9
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Prata IO, Cubillos EFG, Krüger A, Barbosa D, Martins J, Setubal JC, Wunderlich G. Plasmodium falciparum Acetyl-CoA Synthetase Is Essential for Parasite Intraerythrocytic Development and Chromatin Modification. ACS Infect Dis 2021; 7:3224-3240. [PMID: 34766750 DOI: 10.1021/acsinfecdis.1c00414] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The malaria parasite Plasmodium falciparum possesses a unique Acetyl-CoA Synthetase (PfACS), which provides acetyl moieties for different metabolic and regulatory cellular pathways. We characterized PfACS and studied its role focusing on epigenetic modifications using the var gene family as reporter genes. For this, mutant lines to modulate plasmodial ACS expression by degron-mediated protein degradation and ribozyme-induced transcript decay were created. Additionally, an inhibitor of the human Acetyl-CoA Synthetase 2 was tested for its effectiveness in interfering with PfACS. The knockdown of PfACS or its inhibition resulted in impaired parasite growth. Decreased levels of PfACS also led to differential histone acetylation patterns, altered variant gene expression, and concomitantly decreased cytoadherence of infected red blood cells containing knocked-down parasites. Further, ChIP analysis revealed the presence of PfACS in many loci in ring stage parasites, underscoring its involvement in the regulation of chromatin. Due to its central function in the plasmodial metabolism and significant differences to human ACS, PfACS is an interesting target for drug development.
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Affiliation(s)
- Isadora Oliveira Prata
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, 05508-000 São Paulo-SP, Brazil
| | - Eliana Fernanda Galindo Cubillos
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, 05508-000 São Paulo-SP, Brazil
| | - Arne Krüger
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, 05508-000 São Paulo-SP, Brazil
| | - Deibs Barbosa
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes 748, 05508-000 São Paulo-SP, Brazil
| | - Joaquim Martins
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes 748, 05508-000 São Paulo-SP, Brazil
| | - João Carlos Setubal
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes 748, 05508-000 São Paulo-SP, Brazil
| | - Gerhard Wunderlich
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, 05508-000 São Paulo-SP, Brazil
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10
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Wang S, Zeng W, Zhao W, Xiang Z, Zhao H, Yang Q, Li X, Duan M, Li X, Wang X, Si Y, Rosenthal BM, Yang Z. Comparison of in vitro transformation efficiency methods for Plasmodium falciparum. Mol Biochem Parasitol 2021; 247:111432. [PMID: 34826523 DOI: 10.1016/j.molbiopara.2021.111432] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/03/2021] [Accepted: 11/19/2021] [Indexed: 11/30/2022]
Abstract
Poor efficiency plagues conventional methods to transfect Plasmodium falciparum with genetic modifications, impeding research aimed at limiting the damage wrought by this agent of severe malaria. Here, we sought and documented improvements, using fluoresce imaging, cell sorting, and drug selection as means to measure efficiency. Through the transfection of EGFP plasmid, the transfection efficiency of the three methods used in this study was as high as 10-3. A method that pre-loaded uninfected erythrocytes with plasmids using the Bio-Rad Gene Pulser Xcell achieved the highest efficiency (0.48%±0.06%), twice the efficiency of a method using nuclear transfection of ring stages employing the 4D-NucleofectorTM X Kit L. We also evaluated an approach using the Nucleofactor system to transform schizont stages. We considered efficiency and the time required to complete drug screening experiments when evaluating transfection methods. Fluorescence measurements confirmed greater efficiencies for the Pre-load method (52.4% vs. 25%; P < 0.0001), but the Nuc-Ring method required less time to complete drug selection experiments following CRISPR/Cas9 editing. These data should benefit future studies seeking to remove or modify genes of P. falciparum.
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Affiliation(s)
- Siqi Wang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province 650500, China; National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), NHC Key Laboratory of Parasite and Vector Biology (National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention), Shanghai, 200025, China
| | - Weilin Zeng
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province 650500, China
| | - Wei Zhao
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province 650500, China
| | - Zheng Xiang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province 650500, China
| | - Hui Zhao
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province 650500, China
| | - Qi Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province 650500, China
| | - Xinxin Li
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province 650500, China
| | - Mengxi Duan
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province 650500, China
| | - Xiaosong Li
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province 650500, China
| | - Xun Wang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province 650500, China
| | - Yu Si
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province 650500, China
| | - Benjamin M Rosenthal
- Animal Parasitic Disease Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture, Beltsville, MD 20705, USA
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province 650500, China.
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11
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Schumann R, Bischoff E, Klaus S, Möhring S, Flock J, Keller S, Remans K, Ganter M, Deponte M. Protein abundance and folding rather than the redox state of Kelch13 determine the artemisinin susceptibility of Plasmodium falciparum. Redox Biol 2021; 48:102177. [PMID: 34773836 PMCID: PMC8600086 DOI: 10.1016/j.redox.2021.102177] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/25/2021] [Accepted: 10/30/2021] [Indexed: 12/30/2022] Open
Abstract
Decreased susceptibilities of the human malaria parasite Plasmodium falciparum towards the endoperoxide antimalarial artemisinin are linked to mutations of residue C580 of PfKelch13, a homologue of the redox sensor Keap1 and other vertebrate BTB-Kelch proteins. Here, we addressed whether mutations alter the artemisinin susceptibility by modifying the redox properties of PfKelch13 or by compromising its native fold or abundance. Using selection-linked integration and the glmS ribozyme, efficient down-regulation of PfKelch13 resulted in ring-stage survival rates around 40%. While the loss of the thiol group of C469 or of the potential disulfide bond between residues C580 and C532 had no effect on the artemisinin susceptibility, the thiol group of C473 could not be replaced. Furthermore, we detected two different forms of PfKelch13 with distinct electrophoretic mobilities around 85 and 95 kDa, suggesting an unidentified post-translational modification. We also established a protocol for the production of recombinant PfKelch13 and produced an antibody against the protein. Recombinant PfKelch13 adopted alternative oligomeric states and only two of its seven cysteine residues, C469 and C473, reacted with Ellman's reagent. While common field mutations resulted in misfolded and completely insoluble recombinant PfKelch13, cysteine-to-serine replacements had no effect on the solubility except for residue C473. In summary, in contrast to residues C469, C532, and C580, the surface-exposed thiol group of residue C473 appears to be essential. However, not the redox properties but impaired folding of PfKelch13, resulting in a decreased PfKelch13 abundance, alters the artemisinin susceptibility and is the central parameter for mutant selection.
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Affiliation(s)
- Robin Schumann
- Faculty of Chemistry, Comparative Biochemistry, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany
| | - Eileen Bischoff
- Faculty of Chemistry, Comparative Biochemistry, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany
| | - Severina Klaus
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, D-69120, Heidelberg, Germany
| | - Sophie Möhring
- Faculty of Chemistry, Comparative Biochemistry, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany
| | - Julia Flock
- Protein Expression and Purification Core Facility, European Molecular Biology Laboratory (EMBL), D-69117, Heidelberg, Germany
| | - Sandro Keller
- Molecular Biophysics, Technische Universität Kaiserslautern, D-67663, Kaiserslautern, Germany; Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstr. 50/III, 8010, Graz, Austria; Field of Excellence BioHealth, University of Graz, Graz, Austria; BioTechMed-Graz, Graz, Austria
| | - Kim Remans
- Protein Expression and Purification Core Facility, European Molecular Biology Laboratory (EMBL), D-69117, Heidelberg, Germany
| | - Markus Ganter
- Centre for Infectious Diseases, Parasitology, Heidelberg University Hospital, D-69120, Heidelberg, Germany
| | - Marcel Deponte
- Faculty of Chemistry, Comparative Biochemistry, Technische Universität Kaiserslautern, D-67663 Kaiserslautern, Germany.
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12
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Cubillos EFG, Prata IO, Fotoran WL, Ranford-Cartwright L, Wunderlich G. The Transcription Factor PfAP2-O Influences Virulence Gene Transcription and Sexual Development in Plasmodium falciparum. Front Cell Infect Microbiol 2021; 11:669088. [PMID: 34268135 PMCID: PMC8275450 DOI: 10.3389/fcimb.2021.669088] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/23/2021] [Indexed: 12/02/2022] Open
Abstract
The human malaria parasite Plasmodium falciparum expresses variant PfEMP1 proteins on the infected erythrocyte, which function as ligands for endothelial receptors in capillary vessels, leading to erythrocyte sequestration and severe malaria. The factors that orchestrate the mono-allelic expression of the 45–90 PfEMP1-encoding var genes within each parasite genome are still not fully identified. Here, we show that the transcription factor PfAP2-O influences the transcription of var genes. The temporary knockdown of PfAP2-O leads to a complete loss of var transcriptional memory and a decrease in cytoadherence in CD36 adherent parasites. AP2-O-knocked-down parasites exhibited also significant reductions in transmission through Anopheles mosquitoes. We propose that PfAP2-O is, beside its role in transmission stages, also one of the virulence gene transcriptional regulators and may therefore be exploited as an important target to disrupt severe malaria and block parasite transmission.
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Affiliation(s)
- Eliana F G Cubillos
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Isadora Oliveira Prata
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Wesley Luzetti Fotoran
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Lisa Ranford-Cartwright
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
| | - Gerhard Wunderlich
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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13
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Macedo-Silva T, Desai SA, Wunderlich G. Improved Plasmodium falciparum dilution cloning through efficient quantification of parasite numbers and c-SNARF detection. Malar J 2021; 20:279. [PMID: 34162381 PMCID: PMC8220766 DOI: 10.1186/s12936-021-03816-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 06/12/2021] [Indexed: 11/24/2022] Open
Abstract
Background Molecular and genetic studies of blood-stage Plasmodium falciparum parasites require limiting dilution cloning and prolonged cultivation in microplates. The entire process is laborious and subject to errors due to inaccurate dilutions at the onset and failed detection of parasite growth in individual microplate wells. Methods To precisely control the number of parasites dispensed into each microplate well, parasitaemia and total cell counts were determined by flow cytometry using parasite cultures stained with ethidium bromide or SYBR Green I. Microplates were seeded with 0.2 or 0.3 infected cells/well and cultivated with fresh erythrocytes. The c-SNARF fluorescent pH indicator was then used to reliably detect parasite growth. Results Flow cytometry required less time than the traditional approach of estimating parasitaemia and cell numbers by microscopic examination. The resulting dilutions matched predictions from Poisson distribution calculations and yielded clonal lines. Addition of c-SNARF to media permitted rapid detection of parasite growth in microplate wells with high confidence. Conclusion The combined use of flow cytometry for precise dilution and the c-SNARF method for detection of growth improves limiting dilution cloning of P. falciparum. This simple approach saves time, is scalable, and maximizes identification of desired parasite clones. It will facilitate DNA transfection studies and isolation of parasite clones from ex vivo blood samples.
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Affiliation(s)
- Tatiane Macedo-Silva
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil.,The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Sanjay A Desai
- The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Gerhard Wunderlich
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil.
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14
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Messenger RNAs with large numbers of upstream open reading frames are translated via leaky scanning and reinitiation in the asexual stages of Plasmodium falciparum. Parasitology 2020; 147:1100-1113. [DOI: 10.1017/s0031182020000840] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AbstractThe genome of Plasmodium falciparum has one of the most skewed base-pair compositions of any eukaryote, with an AT content of 80–90%. As start and stop codons are AT-rich, the probability of finding upstream open reading frames (uORFs) in messenger RNAs (mRNAs) is high and parasite mRNAs have an average of 11 uORFs in their leader sequences. Similar to other eukaryotes, uORFs repress the translation of the downstream open reading frame (dORF) in P. falciparum, yet the parasite translation machinery is able to bypass these uORFs and reach the dORF to initiate translation. This can happen by leaky scanning and/or reinitiation.In this report, we assessed leaky scanning and reinitiation by studying the effect of uORFs on the translation of a dORF, in this case, the luciferase reporter gene, and showed that both mechanisms are employed in the asexual blood stages of P. falciparum. Furthermore, in addition to the codon usage of the uORF, translation of the dORF is governed by the Kozak sequence and length of the uORF, and inter-cistronic distance between the uORF and dORF. Based on these features whole-genome data was analysed to uncover classes of genes that might be regulated by uORFs. This study indicates that leaky scanning and reinitiation appear to be widespread in asexual stages of P. falciparum, which may require modifications of existing factors that are involved in translation initiation in addition to novel, parasite-specific proteins.
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15
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Linzke M, Yan SLR, Tárnok A, Ulrich H, Groves MR, Wrenger C. Live and Let Dye: Visualizing the Cellular Compartments of the Malaria Parasite Plasmodium falciparum. Cytometry A 2019; 97:694-705. [PMID: 31738009 DOI: 10.1002/cyto.a.23927] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 10/03/2019] [Accepted: 10/24/2019] [Indexed: 12/15/2022]
Abstract
Malaria remains one of the deadliest diseases worldwide and it is caused by the protozoan parasite Plasmodium spp. Parasite visualization is an important tool for the correct detection of malarial cases but also to understand its biology. Advances in visualization techniques promote new insights into the complex life cycle and biology of Plasmodium parasites. Live cell imaging by fluorescence microscopy or flow cytometry are the foundation of the visualization technique for malaria research. In this review, we present an overview of possibilities in live cell imaging of the malaria parasite. We discuss some of the state-of-the-art techniques to visualize organelles and processes of the parasite and discuss limitation and advantages of each technique. © 2019 International Society for Advancement of Cytometry.
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Affiliation(s)
- Marleen Linzke
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo, São Paulo, 05508-000, Brazil
| | - Sun Liu Rei Yan
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo, São Paulo, 05508-000, Brazil
| | - Attila Tárnok
- Institute for Medical Informatics, Statistics and Epidemiology, Medical Faculty, University Leipzig, D-04107, Härtelstraße 16-18, Leipzig, Germany
| | - Henning Ulrich
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes 748, São Paulo, São Paulo, 05508-900, Brazil
| | - Matthew R Groves
- Structural Biology Unit, Department of Pharmacy, Faculty of Science and Engineering, University of Groningen, 9713AV, Antonius Deusinglaan 1, AV Groningen, The Netherlands
| | - Carsten Wrenger
- Unit for Drug Discovery, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo, São Paulo, 05508-000, Brazil
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16
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Gilson PR, Kumarasingha R, Thompson J, Zhang X, Penington JS, Kalhor R, Bullen HE, Lehane AM, Dans MG, de Koning-Ward TF, Holien JK, Soares da Costa TP, Hulett MD, Buskes MJ, Crabb BS, Kirk K, Papenfuss AT, Cowman AF, Abbott BM. A 4-cyano-3-methylisoquinoline inhibitor of Plasmodium falciparum growth targets the sodium efflux pump PfATP4. Sci Rep 2019; 9:10292. [PMID: 31311978 PMCID: PMC6635429 DOI: 10.1038/s41598-019-46500-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/28/2019] [Indexed: 12/31/2022] Open
Abstract
We developed a novel series of antimalarial compounds based on a 4-cyano-3-methylisoquinoline. Our lead compound MB14 achieved modest inhibition of the growth in vitro of the human malaria parasite, Plasmodium falciparum. To identify its biological target we selected for parasites resistant to MB14. Genome sequencing revealed that all resistant parasites bore a single point S374R mutation in the sodium (Na+) efflux transporter PfATP4. There are many compounds known to inhibit PfATP4 and some are under preclinical development. MB14 was shown to inhibit Na+ dependent ATPase activity in parasite membranes, consistent with the compound targeting PfATP4 directly. PfATP4 inhibitors cause swelling and lysis of infected erythrocytes, attributed to the accumulation of Na+ inside the intracellular parasites and the resultant parasite swelling. We show here that inhibitor-induced lysis of infected erythrocytes is dependent upon the parasite protein RhopH2, a component of the new permeability pathways that are induced by the parasite in the erythrocyte membrane. These pathways mediate the influx of Na+ into the infected erythrocyte and their suppression via RhopH2 knockdown limits the accumulation of Na+ within the parasite hence protecting the infected erythrocyte from lysis. This study reveals a role for the parasite-induced new permeability pathways in the mechanism of action of PfATP4 inhibitors.
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Affiliation(s)
- Paul R Gilson
- Burnet Institute, Melbourne, Victoria, 3004, Australia. .,Monash University, Melbourne, Victoria, 3800, Australia.
| | | | - Jennifer Thompson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia
| | - Xinxin Zhang
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | | | - Robabeh Kalhor
- La Trobe University, Melbourne, Victoria, 3086, Australia
| | | | - Adele M Lehane
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Madeline G Dans
- Burnet Institute, Melbourne, Victoria, 3004, Australia.,School of Medicine, Deakin University, Waurn Ponds, Victoria, 3216, Australia
| | | | - Jessica K Holien
- St. Vincent's Institute of Medical Research, Melbourne, Victoria, 3065, Australia
| | | | - Mark D Hulett
- La Trobe University, Melbourne, Victoria, 3086, Australia
| | | | - Brendan S Crabb
- Burnet Institute, Melbourne, Victoria, 3004, Australia.,Monash University, Melbourne, Victoria, 3800, Australia.,University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Kiaran Kirk
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Anthony T Papenfuss
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, 3052, Australia.,University of Melbourne, Melbourne, Victoria, 3010, Australia
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17
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Scarpelli PH, Tessarin‐Almeida G, Viçoso KL, Lima WR, Borges‐Pereira L, Meissner KA, Wrenger C, Rafaello A, Rizzuto R, Pozzan T, Garcia CRS. Melatonin activates FIS1, DYN1, and DYN2 Plasmodium falciparum related-genes for mitochondria fission: Mitoemerald-GFP as a tool to visualize mitochondria structure. J Pineal Res 2019; 66:e12484. [PMID: 29480948 PMCID: PMC6585791 DOI: 10.1111/jpi.12484] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 02/01/2018] [Indexed: 02/06/2023]
Abstract
Malaria causes millions of deaths worldwide and is considered a huge burden to underdeveloped countries. The number of cases with resistance to all antimalarials is continuously increasing, making the identification of novel drugs a very urgent necessity. A potentially very interesting target for novel therapeutic intervention is the parasite mitochondrion. In this work, we studied in Plasmodium falciparum 3 genes coding for proteins homologues of the mammalian FIS1 (Mitochondrial Fission Protein 1) and DRP1 (Dynamin Related Protein 1) involved in mitochondrial fission. We studied the expression of P. falciparum genes that show ample sequence and structural homologies with the mammalian counterparts, namely FIS1, DYN1, and DYN2. The encoded proteins are characterized by a distinct pattern of expression throughout the erythrocytic cycle of P. falciparum, and their mRNAs are modulated by treating the parasite with the host hormone melatonin. We have previously reported that the knockout of the Plasmodium gene that codes for protein kinase 7 is essential for melatonin sensing. We here show that PfPk7 knockout results in major alterations of mitochondrial fission genes expression when compared to wild-type parasites, and no change in fission proteins expression upon treatment with the host hormone. Finally, we have compared the morphological characteristics (using MitoTracker Red CMX Ros) and oxygen consumption properties of P. falciparum mitochondria in wild-type parasites and PfPk7 Knockout strains. A novel GFP construct targeted to the mitochondrial matrix to wild-type parasites was also developed to visualize P. falciparum mitochondria. We here show that, the functional characteristics of P. falciparum are profoundly altered in cells lacking protein kinase 7, suggesting that this enzyme plays a major role in the control of mitochondrial morphogenesis and maturation during the intra-erythrocyte cell cycle progression.
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Affiliation(s)
- Pedro H. Scarpelli
- Departamento de ParasitologiaInstituto de Ciências BiomédicasUniversidade de São PauloSão PauloBrazil
- Departamento de FisiologiaInstituto de BiociênciasUniversidade de São PauloSão PauloBrazil
| | | | - Kênia Lopes Viçoso
- Departamento de FisiologiaInstituto de BiociênciasUniversidade de São PauloSão PauloBrazil
| | - Wania Rezende Lima
- Instituto de Ciências Exatas e Naturais‐MedicinaUniversidade Federal de Mato Grosso‐Campus RondonópolisMato GrossoBrazil
| | - Lucas Borges‐Pereira
- Departamento de FisiologiaInstituto de BiociênciasUniversidade de São PauloSão PauloBrazil
| | - Kamila Anna Meissner
- Departamento de ParasitologiaInstituto de Ciências BiomédicasUniversidade de São PauloSão PauloBrazil
| | - Carsten Wrenger
- Departamento de ParasitologiaInstituto de Ciências BiomédicasUniversidade de São PauloSão PauloBrazil
| | - Anna Rafaello
- CNR Neurosciences InstituteUniversity of PadovaPadovaItaly
| | | | - Tullio Pozzan
- CNR Neurosciences InstituteUniversity of PadovaPadovaItaly
| | - Celia R. S. Garcia
- Departamento de FisiologiaInstituto de BiociênciasUniversidade de São PauloSão PauloBrazil
- Departamento de Fisiologia, Instituto de BiociênciasUniversidade de São PauloSão PauloBrazil
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18
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Double-stranded RNA reduces growth rates of the gut parasite Crithidia mellificae. Parasitol Res 2019; 118:715-721. [DOI: 10.1007/s00436-018-6176-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 12/11/2018] [Indexed: 10/27/2022]
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19
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Sanders PR, Dickerman BK, Charnaud SC, Ramsland PA, Crabb BS, Gilson PR. The N-terminus of EXP2 forms the membrane-associated pore of the protein exporting translocon PTEX in Plasmodium falciparum. J Biochem 2018; 165:239-248. [DOI: 10.1093/jb/mvy099] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 11/20/2018] [Indexed: 12/12/2022] Open
Affiliation(s)
| | | | | | - Paul A Ramsland
- Burnet Institute, Melbourne, VIC, Australia
- University of Melbourne, Melbourne, VIC, Australia
- RMIT University, Bundoora, VIC, Australia
- Monash University, Melbourne, VIC, Australia
| | - Brendan S Crabb
- Burnet Institute, Melbourne, VIC, Australia
- University of Melbourne, Melbourne, VIC, Australia
- Monash University, Melbourne, VIC, Australia
| | - Paul R Gilson
- Burnet Institute, Melbourne, VIC, Australia
- Monash University, Melbourne, VIC, Australia
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20
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Knockdown of the translocon protein EXP2 in Plasmodium falciparum reduces growth and protein export. PLoS One 2018; 13:e0204785. [PMID: 30439948 PMCID: PMC6237293 DOI: 10.1371/journal.pone.0204785] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 10/30/2018] [Indexed: 11/23/2022] Open
Abstract
Malaria parasites remodel their host erythrocytes to gain nutrients and avoid the immune system. Host erythrocytes are modified by hundreds of effector proteins exported from the parasite into the host cell. Protein export is mediated by the PTEX translocon comprising five core components of which EXP2 is considered to form the putative pore that spans the vacuole membrane enveloping the parasite within its erythrocyte. To explore the function and importance of EXP2 for parasite survival in the asexual blood stage of Plasmodium falciparum we inducibly knocked down the expression of EXP2. Reduction in EXP2 expression strongly reduced parasite growth proportional to the degree of protein knockdown and tended to stall development about half way through the asexual cell cycle. Once the knockdown inducer was removed and EXP2 expression restored, parasite growth recovered dependent upon the length and degree of knockdown. To establish EXP2 function and hence the basis for growth reduction, the trafficking of an exported protein was monitored following EXP2 knockdown. This resulted in severe attenuation of protein export and is consistent with EXP2, and PTEX in general, being the conduit for export of proteins into the host compartment.
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21
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Narayan A, Mastud P, Thakur V, Rathod PK, Mohmmed A, Patankar S. Heterologous expression in Toxoplasma gondii reveals a topogenic signal anchor in a Plasmodium apicoplast protein. FEBS Open Bio 2018; 8:1746-1762. [PMID: 30410855 PMCID: PMC6212639 DOI: 10.1002/2211-5463.12527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 08/24/2018] [Accepted: 09/08/2018] [Indexed: 12/27/2022] Open
Abstract
Glutathione peroxidase‐like thioredoxin peroxidase (PfTPxGl) is an antioxidant enzyme trafficked to the apicoplast, a secondary endosymbiotic organelle, in Plasmodium falciparum. Apicoplast trafficking signals usually consist of N‐terminal signal and transit peptides, but the trafficking signal of PfTPxGl appears to exhibit important differences. As transfection is a protracted process in P. falciparum, we expressed the N terminus of PfTPxGl as a GFP fusion protein in a related apicomplexan, Toxoplasma gondii, in order to dissect its trafficking signals. We show that PfTPxGl possesses an N‐terminal signal anchor that takes the protein to the endoplasmic reticulum in Toxoplasma—this is the first step in the apicoplast targeting pathway. We dissected the residues important for endomembrane system uptake, membrane anchorage, orientation, spacing, and cleavage. Protease protection assays and fluorescence complementation revealed that the C terminus of the protein lies in the ER lumen, a topology that is proposed to be retained in the apicoplast. Additionally, we examined one mutant, responsible for altered PfTPxGl targeting in Toxoplasma, in Plasmodium. This study has demonstrated that PfTPxGl belongs to an emergent class of proteins that possess signal anchors, unlike the canonical bipartite targeting signals employed for the trafficking of luminal apicoplast proteins. This work adds to the mounting evidence that the signals involved in the targeting of apicoplast membrane proteins may not be as straightforward as those of luminal proteins, and also highlights the usefulness of T. gondii as a heterologous system in certain aspects of this study, such as reducing screening time and facilitating the verification of membrane topology.
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Affiliation(s)
- Aishwarya Narayan
- Department of Biosciences and Bioengineering IIT Bombay Mumbai India
| | - Pragati Mastud
- Department of Biosciences and Bioengineering IIT Bombay Mumbai India
| | - Vandana Thakur
- International Centre for Genetic Engineering and Biotechnology New Delhi India
| | | | - Asif Mohmmed
- International Centre for Genetic Engineering and Biotechnology New Delhi India
| | - Swati Patankar
- Department of Biosciences and Bioengineering IIT Bombay Mumbai India
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22
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Araujo RBD, Silva TM, Kaiser CS, Leite GF, Alonso D, Ribolla PEM, Wunderlich G. Independent regulation of Plasmodium falciparum rif gene promoters. Sci Rep 2018; 8:9332. [PMID: 29921926 PMCID: PMC6008437 DOI: 10.1038/s41598-018-27646-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 06/07/2018] [Indexed: 11/09/2022] Open
Abstract
All Plasmodium species express variant antigens which may mediate immune escape in the vertebrate host. In Plasmodium falciparum, the rif gene family encodes variant antigens which are partly exposed on the infected red blood cell surface and may function as virulence factors. Not all rif genes are expressed at the same time and it is unclear what controls rif gene expression. In this work, we addressed global rif transcription using plasmid vectors with two drug resistance markers, one controlled by a rif 5′ upstream region and the second by a constitutively active promoter. After spontaneous integration into the genome of one construct, we observed that the resistance marker controlled by the rif 5′ upstream region was expressed dependent on the applied drug pressure. Then, the global transcription of rif genes in these transfectants was compared in the presence or absence of drugs. The relative transcript quantities of all rif loci did not change profoundly between strains grown with or without drug. We conclude that either there is no crosstalk between rif loci or that the elusive system of allelic exclusion of rif gene transcription is not controlled by their 5′ upstream region alone.
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Affiliation(s)
- Rosana Beatriz Duque Araujo
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo - SP, 05508000, Brazil
| | - Tatiane Macedo Silva
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo - SP, 05508000, Brazil
| | - Charlotte Sophie Kaiser
- Institute of Animal Physiology, Schloßplatz 8, Westfälische Wilhelms Universität, Münster, Germany
| | - Gabriela Fernandes Leite
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo - SP, 05508000, Brazil
| | - Diego Alonso
- Department of Parasitology, IBB/IBTEC, State University of São Paulo, Botucatu, São Paulo, Brazil
| | | | - Gerhard Wunderlich
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo - SP, 05508000, Brazil.
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23
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Charnaud SC, Jonsdottir TK, Sanders PR, Bullen HE, Dickerman BK, Kouskousis B, Palmer CS, Pietrzak HM, Laumaea AE, Erazo AB, McHugh E, Tilley L, Crabb BS, Gilson PR. Spatial organization of protein export in malaria parasite blood stages. Traffic 2018; 19:605-623. [DOI: 10.1111/tra.12577] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 04/21/2018] [Accepted: 04/24/2018] [Indexed: 12/29/2022]
Affiliation(s)
| | - Thorey K. Jonsdottir
- Burnet Institute; Melbourne Australia
- Peter Doherty Institute for Infection and Immunity, University of Melbourne; Melbourne Australia
| | | | | | | | - Betty Kouskousis
- Burnet Institute; Melbourne Australia
- Monash Micro Imaging, Monash University; Melbourne Australia
| | - Catherine S. Palmer
- Burnet Institute; Melbourne Australia
- Monash Micro Imaging, Monash University; Melbourne Australia
| | | | | | | | - Emma McHugh
- Department of Biochemistry and Molecular Biology, University of Melbourne; Melbourne Australia
| | - Leann Tilley
- Department of Biochemistry and Molecular Biology, University of Melbourne; Melbourne Australia
| | - Brendan S. Crabb
- Burnet Institute; Melbourne Australia
- Peter Doherty Institute for Infection and Immunity, University of Melbourne; Melbourne Australia
- Department of Microbiology, Monash University; Melbourne Australia
| | - Paul R. Gilson
- Burnet Institute; Melbourne Australia
- Department of Microbiology, Monash University; Melbourne Australia
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24
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Wezena CA, Alisch R, Golzmann A, Liedgens L, Staudacher V, Pradel G, Deponte M. The cytosolic glyoxalases of Plasmodium falciparum are dispensable during asexual blood-stage development. MICROBIAL CELL 2017; 5:32-41. [PMID: 29354648 PMCID: PMC5772037 DOI: 10.15698/mic2018.01.608] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The enzymes glyoxalase 1 and 2 (Glo1 and Glo2) are found in most eukaryotes and catalyze the glutathione-dependent conversion of 2-oxoaldehydes to 2-hydroxycarboxylic acids. Four glyoxalases are encoded in the genome of the malaria parasite Plasmodium falciparum, the cytosolic enzymes PfGlo1 and PfcGlo2, the apicoplast enzyme PftGlo2, and an inactive Glo1-like protein that also carries an apicoplast-targeting sequence. Inhibition or knockout of the Plasmodium glyoxalases was hypothesized to lead to an accumulation of 2-oxoaldehydes and advanced glycation end-products (AGE) in the host-parasite unit and to result in parasite death. Here, we generated clonal P. falciparum strain 3D7 knockout lines for PFGLO1 and PFcGLO2 using the CRISPR-Cas9 system. Although 3D7Δglo1 knockout clones had an increased susceptibility to external glyoxal, all 3D7Δglo1 and 3D7Δcglo2 knockout lines were viable and showed no significant growth phenotype under standard growth conditions. Furthermore, the lack of PfcGlo2, but not PfGlo1, increased gametocyte commitment in the knockout lines. In summary, PfGlo1 and PfcGlo2 are dispensable during asexual blood-stage development while the loss of PfcGlo2 may induce the formation of transmissible gametocytes. These combined data show that PfGlo1 and PfcGlo2 are most likely not suited as targets for selective drug development.
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Affiliation(s)
- Cletus A Wezena
- Department of Parasitology, Ruprecht-Karls University, D-69120 Heidelberg, Germany
| | - Romy Alisch
- Department of Parasitology, Ruprecht-Karls University, D-69120 Heidelberg, Germany
| | - Alexandra Golzmann
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, D-52074 Aachen, Germany
| | - Linda Liedgens
- Department of Parasitology, Ruprecht-Karls University, D-69120 Heidelberg, Germany
| | - Verena Staudacher
- Department of Parasitology, Ruprecht-Karls University, D-69120 Heidelberg, Germany.,Department of Chemistry/Biochemistry, University of Kaiserslautern, D-67663 Kaiserslautern, Germany
| | - Gabriele Pradel
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, D-52074 Aachen, Germany
| | - Marcel Deponte
- Department of Parasitology, Ruprecht-Karls University, D-69120 Heidelberg, Germany.,Department of Chemistry/Biochemistry, University of Kaiserslautern, D-67663 Kaiserslautern, Germany
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25
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Moraes Barros RR, Gibson TJ, Kite WA, Sá JM, Wellems TE. Comparison of two methods for transformation of Plasmodium knowlesi: Direct schizont electroporation and spontaneous plasmid uptake from plasmid-loaded red blood cells. Mol Biochem Parasitol 2017; 218:16-22. [PMID: 28988930 DOI: 10.1016/j.molbiopara.2017.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 09/19/2017] [Accepted: 10/02/2017] [Indexed: 01/04/2023]
Abstract
Human infections from Plasmodium knowlesi present challenges to malaria control in Southeast Asia. P. knowlesi also offers a model for other human malaria species including Plasmodium vivax. P. knowlesi parasites can be cultivated in the laboratory, and their transformation is standardly performed by direct electroporation of schizont-infected red blood cells (RBCs) with plasmid DNA. Here we show that the efficiency of direct electroporation is exquisitely dependent on developmental age of the schizonts. Additionally, we show that transformation of P. knowlesi can be achieved without direct electroporation by using the parasite's ability to infect and take up DNA from plasmid-loaded RBCs. Transformation with plasmid-loaded RBCs does not require labor-intensive preparations of schizont-infected RBCs as for direct electroporation, and parasite damage from high voltage discharge is avoided. Further studies of the mechanism of spontaneous DNA uptake may suggest strategies for improved transformation and provide insights into the transport pathways of apicomplexans.
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Affiliation(s)
- Roberto R Moraes Barros
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-8132, USA.
| | - Tyler J Gibson
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-8132, USA.
| | - Whitney A Kite
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-8132, USA.
| | - Juliana M Sá
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-8132, USA.
| | - Thomas E Wellems
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-8132, USA.
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26
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Knockdown of the Plasmodium falciparum SURFIN4.1 antigen leads to an increase of its cognate transcript. PLoS One 2017; 12:e0183129. [PMID: 28800640 PMCID: PMC5553854 DOI: 10.1371/journal.pone.0183129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 07/31/2017] [Indexed: 11/24/2022] Open
Abstract
The genome of the malaria parasite Plasmodium falciparum contains the surf gene family which encodes large transmembrane proteins of unknown function. While some surf alleles appear to be expressed in sexual stages, others occur in asexual blood stage forms and may be associated to virulence-associated processes and undergo transcriptional switching. We accessed the transcription of surf genes along multiple invasions by real time PCR. Based on the observation of persistent expression of gene surf4.1, we created a parasite line which expresses a conditionally destabilized SURFIN4.1 protein. Upon destabilization of the protein, no interference of parasite growth or morphological changes were detected. However, we observed a strong increase in the transcript quantities of surf4.1 and sometimes of other surf genes in knocked-down parasites. While this effect was reversible when SURFIN4.1 was stabilized again after a few days of destabilization, longer destabilization periods resulted in a transcriptional switch away from surf4.1. When we tested if a longer transcript half-life was responsible for increased transcript detection in SURFIN4.1 knocked-down parasites, no alteration was found compared to control parasite lines. This suggests a specific feedback of the expressed SURFIN protein to its transcript pointing to a novel type of regulation, inedited in Plasmodium.
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27
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Dickerman BK, Elsworth B, Cobbold SA, Nie CQ, McConville MJ, Crabb BS, Gilson PR. Identification of inhibitors that dually target the new permeability pathway and dihydroorotate dehydrogenase in the blood stage of Plasmodium falciparum. Sci Rep 2016; 6:37502. [PMID: 27874068 PMCID: PMC5118696 DOI: 10.1038/srep37502] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 10/28/2016] [Indexed: 12/22/2022] Open
Abstract
Plasmodium parasites are responsible for the devastating disease malaria that affects hundreds of millions of people each year. Blood stage parasites establish new permeability pathways (NPPs) in infected red blood cell membranes to facilitate the uptake of nutrients and removal of parasite waste products. Pharmacological inhibition of the NPPs is expected to lead to nutrient starvation and accumulation of toxic metabolites resulting in parasite death. Here, we have screened a curated library of antimalarial compounds, the MMV Malaria Box, identifying two compounds that inhibit NPP function. Unexpectedly, metabolic profiling suggested that both compounds also inhibit dihydroorotate dehydrogense (DHODH), which is required for pyrimidine synthesis and is a validated drug target in its own right. Expression of yeast DHODH, which bypasses the need for the parasite DHODH, increased parasite resistance to these compounds. These studies identify two potential candidates for therapeutic development that simultaneously target two essential pathways in Plasmodium, NPP and DHODH.
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Affiliation(s)
| | - Brendan Elsworth
- Burnet Institute, Melbourne, Victoria, Australia
- Monash University, Clayton, Victoria, Australia
| | - Simon A. Cobbold
- Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia
| | | | - Malcolm J. McConville
- Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia
| | - Brendan S. Crabb
- Burnet Institute, Melbourne, Victoria, Australia
- Monash University, Clayton, Victoria, Australia
- Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia
| | - Paul R. Gilson
- Burnet Institute, Melbourne, Victoria, Australia
- Monash University, Clayton, Victoria, Australia
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28
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Metabolomics-Based Screening of the Malaria Box Reveals both Novel and Established Mechanisms of Action. Antimicrob Agents Chemother 2016; 60:6650-6663. [PMID: 27572396 DOI: 10.1128/aac.01226-16] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/16/2016] [Indexed: 12/22/2022] Open
Abstract
High-throughput phenotypic screening of chemical libraries has resulted in the identification of thousands of compounds with potent antimalarial activity, although in most cases, the mechanism(s) of action of these compounds remains unknown. Here we have investigated the mode of action of 90 antimalarial compounds derived from the Malaria Box collection using high-coverage, untargeted metabolomics analysis. Approximately half of the tested compounds induced significant metabolic perturbations in in vitro cultures of Plasmodium falciparum In most cases, the metabolic profiles were highly correlated with known antimalarials, in particular artemisinin, the 4-aminoquinolines, or atovaquone. Select Malaria Box compounds also induced changes in intermediates in essential metabolic pathways, such as isoprenoid biosynthesis (i.e., 2-C-methyl-d-erythritol 2,4-cyclodiphosphate) and linolenic acid metabolism (i.e., traumatic acid). This study provides a comprehensive database of the metabolic perturbations induced by chemically diverse inhibitors and highlights the utility of metabolomics for triaging new lead compounds and defining specific modes of action, which will assist with the development and optimization of new antimalarial drugs.
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29
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Huang F, Zhao F, Liang LP, Zhou M, Qu ZL, Cao YZ, Lin C. Optomizing Transfection Efficiency of Cervical Cancer Cells Transfected by Cationic Liposomes LipofectamineTM2000. Asian Pac J Cancer Prev 2016; 16:7749-54. [PMID: 26625792 DOI: 10.7314/apjcp.2015.16.17.7749] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Currently, cationic liposome has become the commonly used vehicles for gene transfection. Furthermore, one of the most significant steps in microRNAs expression studies is transferring microRNAs into cell cultures successfully. In this study we aim to approach the feasibility of transfection of cervical cancer cell lines mediated by liposome and to obtain the optimized transfection condition for cervical cancer cell lines. MATERIALS AND METHODS Lipofectamine(TM)2000 as the carrier, miR-101 mimic was transfected into Hela cells and Siha cells. Using green fluorescent protein as reporter gene, to set different groups according to cell seeding density, the amount of miRNA , miRNA and the proportion of Liposomes, Whether to add serum into medium to study their impact on the liposomal transfection efficiency. Finally, MTT assay was used to analyze the relative minimal cell toxicity of liposome reagents. RESULTS The seeding density of Hela cell line and Siha are 1.5 x 10(4) (per well of 24 well plates), miRNA amount is 1ul of both, the ratio of miRNA and liposome is 1:0.5 of Hela cell line; 1:0.7 of Siha cell line respectively, after 24 hours we can get the highest transfection efficiency. Compared with serum medium, only Siha cells cultured with serum-free medium obtained higher transfection efficiency before transfection (P<0.01).MTT assay showed that according to the above conditions which has the lowest cytotoxicity. CONCLUSIONS The method of Liposome to transfected is a suitable way and it can be an efficient reagent for miRNA delivery for Hela cells and Siha cells in vitro. It may serve as a reference for the further research or application.
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Affiliation(s)
- Fei Huang
- Department of Pathology, The Affiliated Tumor Hospital Of Xinjiang Medical University, Urumqi, China E-mail :
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30
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Elsworth B, Sanders PR, Nebl T, Batinovic S, Kalanon M, Nie CQ, Charnaud SC, Bullen HE, de Koning Ward TF, Tilley L, Crabb BS, Gilson PR. Proteomic analysis reveals novel proteins associated with the Plasmodium protein exporter PTEX and a loss of complex stability upon truncation of the core PTEX component, PTEX150. Cell Microbiol 2016; 18:1551-1569. [PMID: 27019089 DOI: 10.1111/cmi.12596] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 03/11/2016] [Accepted: 03/22/2016] [Indexed: 11/28/2022]
Abstract
The Plasmodium translocon for exported proteins (PTEX) has been established as the machinery responsible for the translocation of all classes of exported proteins beyond the parasitophorous vacuolar membrane of the intraerythrocytic malaria parasite. Protein export, particularly in the asexual blood stage, is crucial for parasite survival as exported proteins are involved in remodelling the host cell, an essential process for nutrient uptake, waste removal and immune evasion. Here, we have truncated the conserved C-terminus of one of the essential PTEX components, PTEX150, in Plasmodium falciparum in an attempt to create mutants of reduced functionality. Parasites tolerated C-terminal truncations of up to 125 amino acids with no reduction in growth, protein export or the establishment of new permeability pathways. Quantitative proteomic approaches however revealed a decrease in other PTEX subunits associating with PTEX150 in truncation mutants, suggesting a role for the C-terminus of PTEX150 in regulating PTEX stability. Our analyses also reveal three previously unreported PTEX-associated proteins, namely PV1, Pf113 and Hsp70-x (respective PlasmoDB numbers; PF3D7_1129100, PF3D7_1420700 and PF3D7_0831700) and demonstrate that core PTEX proteins exist in various distinct multimeric forms outside the major complex.
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Affiliation(s)
- Brendan Elsworth
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia.,Monash University, Melbourne, VIC, 3800, Australia
| | - Paul R Sanders
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia
| | - Thomas Nebl
- Walter & Eliza Hall Institute, Melbourne, VIC, 3052, Australia
| | - Steven Batinovic
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, VIC, Australia.,ARC Centre of Excellence for Coherent X-ray Science, The University of Melbourne, Melbourne, VIC, Australia.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | | | - Catherine Q Nie
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia
| | - Sarah C Charnaud
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia.,Monash University, Melbourne, VIC, 3800, Australia
| | - Hayley E Bullen
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia
| | | | - Leann Tilley
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, VIC, Australia.,ARC Centre of Excellence for Coherent X-ray Science, The University of Melbourne, Melbourne, VIC, Australia.,Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Brendan S Crabb
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia.,Monash University, Melbourne, VIC, 3800, Australia.,University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Paul R Gilson
- Burnet Institute, 85 Commercial Road, Melbourne, VIC, 3004, Australia. .,Monash University, Melbourne, VIC, 3800, Australia.
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31
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Siciliano G, Alano P. Enlightening the malaria parasite life cycle: bioluminescent Plasmodium in fundamental and applied research. Front Microbiol 2015; 6:391. [PMID: 26029172 PMCID: PMC4426725 DOI: 10.3389/fmicb.2015.00391] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/16/2015] [Indexed: 12/31/2022] Open
Abstract
The unicellular protozoan parasites of the genus Plasmodium impose on human health worldwide the enormous burden of malaria. The possibility to genetically modify several species of malaria parasites represented a major advance in the possibility to elucidate their biology and is now turning laboratory lines of transgenic Plasmodium into precious weapons to fight malaria. Amongst the various genetically modified plasmodia, transgenic parasite lines expressing bioluminescent reporters have been essential to unveil mechanisms of parasite gene expression and to develop in vivo imaging approaches in mouse malaria models. Mainly the human malaria parasite Plasmodium falciparum and the rodent parasite P. berghei have been engineered to express bioluminescent reporters in almost all the developmental stages of the parasite along its complex life cycle between the insect and the vertebrate hosts. Plasmodium lines expressing conventional and improved luciferase reporters are now gaining a central role to develop cell based assays in the much needed search of new antimalarial drugs and to open innovative approaches for both fundamental and applied research in malaria.
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Affiliation(s)
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di SanitàRome, Italy
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32
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Howard BL, Harvey KL, Stewart RJ, Azevedo MF, Crabb BS, Jennings IG, Sanders PR, Manallack DT, Thompson PE, Tonkin CJ, Gilson PR. Identification of potent phosphodiesterase inhibitors that demonstrate cyclic nucleotide-dependent functions in apicomplexan parasites. ACS Chem Biol 2015; 10:1145-54. [PMID: 25555060 DOI: 10.1021/cb501004q] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Apicomplexan parasites, including Plasmodium falciparum and Toxoplasma gondii, the causative agents of severe malaria and toxoplasmosis, respectively, undergo several critical developmental transitions during their lifecycle. Most important for human pathogenesis is the asexual cycle, in which parasites undergo rounds of host cell invasion, replication, and egress (exit), destroying host cell tissue in the process. Previous work has identified important roles for Protein Kinase G (PKG) and Protein Kinase A (PKA) in parasite egress and invasion, yet little is understood about the regulation of cyclic nucleotides, cGMP and cAMP, that activate these enzymes. To address this, we have focused upon the development of inhibitors of 3',5'-cyclic nucleotide phosphodiesterases (PDEs) to block the breakdown of cyclic nucleotides. This was done by repurposing human PDE inhibitors noting various similarities of the human and apicomplexan PDE binding sites. The most potent inhibitors blocked the in vitro proliferation of P. falciparum and T. gondii more potently than the benchmark compound zaprinast. 5-Benzyl-3-isopropyl-1H-pyrazolo[4,3-d]pyrimidin-7(6H)-one (BIPPO) was found to be a potent inhibitor of recombinant P. falciparum PfPDEα and activated PKG-dependent egress of T. gondii and P. falciparum, likely by promoting the exocytosis of micronemes, an activity that was reversed by a specific Protein Kinase G inhibitor. BIPPO also promotes cAMP-dependent phosphorylation of a P. falciparum ligand critical for host cell invasion, suggesting that the compound inhibits single or multiple PDE isoforms that regulate both cGMP and cAMP levels. BIPPO is therefore a useful tool for the dissection of signal transduction pathways in apicomplexan parasites.
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Affiliation(s)
- Brittany L. Howard
- Monash
Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Katherine L. Harvey
- Macfarlane Burnet Institute, Melbourne, Victoria, Australia
- University of Melbourne, Melbourne, Victoria, Australia
| | - Rebecca J. Stewart
- The Walter & Eliza Hall Institute, Melbourne, Victoria, Australia
- Department
of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | | | - Brendan S. Crabb
- Monash
Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- Macfarlane Burnet Institute, Melbourne, Victoria, Australia
- University of Melbourne, Melbourne, Victoria, Australia
| | - Ian G. Jennings
- Monash
Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | | | - David T. Manallack
- Monash
Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Philip E. Thompson
- Monash
Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Christopher J. Tonkin
- The Walter & Eliza Hall Institute, Melbourne, Victoria, Australia
- Department
of Medical Biology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Paul R. Gilson
- Monash
Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
- Macfarlane Burnet Institute, Melbourne, Victoria, Australia
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33
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DNA repair mechanisms and their biological roles in the malaria parasite Plasmodium falciparum. Microbiol Mol Biol Rev 2015; 78:469-86. [PMID: 25184562 DOI: 10.1128/mmbr.00059-13] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Research into the complex genetic underpinnings of the malaria parasite Plasmodium falciparum is entering a new era with the arrival of site-specific genome engineering. Previously restricted only to model systems but now expanded to most laboratory organisms, and even to humans for experimental gene therapy studies, this technology allows researchers to rapidly generate previously unattainable genetic modifications. This technological advance is dependent on DNA double-strand break repair (DSBR), specifically homologous recombination in the case of Plasmodium. Our understanding of DSBR in malaria parasites, however, is based largely on assumptions and knowledge taken from other model systems, which do not always hold true in Plasmodium. Here we describe the causes of double-strand breaks, the mechanisms of DSBR, and the differences between model systems and P. falciparum. These mechanisms drive basic parasite functions, such as meiosis, antigen diversification, and copy number variation, and allow the parasite to continually evolve in the contexts of host immune pressure and drug selection. Finally, we discuss the new technologies that leverage DSBR mechanisms to accelerate genetic investigations into this global infectious pathogen.
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34
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Plasmodium falciparum transfected with ultra bright NanoLuc luciferase offers high sensitivity detection for the screening of growth and cellular trafficking inhibitors. PLoS One 2014; 9:e112571. [PMID: 25392998 PMCID: PMC4231029 DOI: 10.1371/journal.pone.0112571] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 10/08/2014] [Indexed: 11/19/2022] Open
Abstract
Drug discovery is a key part of malaria control and eradication strategies, and could benefit from sensitive and affordable assays to quantify parasite growth and to help identify the targets of potential anti-malarial compounds. Bioluminescence, achieved through expression of exogenous luciferases, is a powerful tool that has been applied in studies of several aspects of parasite biology and high throughput growth assays. We have expressed the new reporter NanoLuc (Nluc) luciferase in Plasmodium falciparum and showed it is at least 100 times brighter than the commonly used firefly luciferase. Nluc brightness was explored as a means to achieve a growth assay with higher sensitivity and lower cost. In addition we attempted to develop other screening assays that may help interrogate libraries of inhibitory compounds for their mechanism of action. To this end parasites were engineered to express Nluc in the cytoplasm, the parasitophorous vacuole that surrounds the intraerythrocytic parasite or exported to the red blood cell cytosol. As proof-of-concept, these parasites were used to develop functional screening assays for quantifying the effects of Brefeldin A, an inhibitor of protein secretion, and Furosemide, an inhibitor of new permeation pathways used by parasites to acquire plasma nutrients.
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35
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Webster WAJ, McFadden GI. From the genome to the phenome: tools to understand the basic biology of Plasmodium falciparum. J Eukaryot Microbiol 2014; 61:655-71. [PMID: 25227912 DOI: 10.1111/jeu.12176] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/01/2014] [Accepted: 09/02/2014] [Indexed: 11/30/2022]
Abstract
Malaria plagues one out of every 30 humans and contributes to almost a million deaths, and the problem could worsen. Our current therapeutic options are compromised by emerging resistance by the parasite to our front line drugs. It is thus imperative to better understand the basic biology of the parasite and develop novel drugs to stem this disease. The most facile approach to analyse a gene's function is to remove it from the genome or inhibit its activity. Although genetic manipulation of the human malaria parasite Plasmodium falciparum is a relatively standard procedure, there is no optimal method to perturb genes essential to the intraerythrocytic development cycle--the part of the life cycle that produces the clinical manifestation of malaria. This is a severe impediment to progress because the phenotype we wish to study is exactly the one that is so elusive. In the absence of any utilitarian way to conditionally delete essential genes, we are prevented from investigating the parasite's most vulnerable points. This review aims to focus on the development of tools identifying essential genes of P. falciparum and our ability to elicit phenotypic mutation.
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Affiliation(s)
- Wesley A J Webster
- Centre for Regional and Rural Futures, School of Life and Environmental Sciences, Deakin University, Burwood, 3125, Victoria, Australia; Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Melbourne, 3010, Victoria, Australia
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36
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Wagner JC, Goldfless SJ, Ganesan SM, Lee MCS, Fidock DA, Niles JC. An integrated strategy for efficient vector construction and multi-gene expression in Plasmodium falciparum. Malar J 2013; 12:373. [PMID: 24160265 PMCID: PMC3842810 DOI: 10.1186/1475-2875-12-373] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 10/22/2013] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The construction of plasmid vectors for transgene expression in the malaria parasite, Plasmodium falciparum, presents major technical hurdles. Traditional molecular cloning by restriction and ligation often yields deletions and re-arrangements when assembling low-complexity (A + T)-rich parasite DNA. Furthermore, the use of large 5'- and 3'- untranslated regions of DNA sequence (UTRs) to drive transgene transcription limits the number of expression cassettes that can be incorporated into plasmid vectors. METHODS To address these challenges, two high fidelity cloning strategies, namely yeast homologous recombination and the Gibson assembly method, were evaluated for constructing P. falciparum vectors. Additionally, some general rules for reliably using the viral 2A-like peptide to express multiple proteins from a single expression cassette while preserving their proper trafficking to various subcellular compartments were assessed. RESULTS Yeast homologous recombination and Gibson assembly were found to be effective strategies for successfully constructing P. falciparum plasmid vectors. Using these cloning methods, a validated family of expression vectors that provide a flexible starting point for user-specific applications was created. These vectors are also compatible with traditional cloning by restriction and ligation, and contain useful combinations of commonly used features for enhancing plasmid segregation and site-specific integration in P. falciparum. Additionally, application of a 2A-like peptide for the synthesis of multiple proteins from a single expression cassette, and some rules for combinatorially directing proteins to discrete subcellular compartments were established. CONCLUSIONS A set of freely available, sequence-verified and functionally validated parts that offer greater flexibility for constructing P. falciparum vectors having expanded expression capacity is provided.
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Affiliation(s)
- Jeffrey C Wagner
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Stephen J Goldfless
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Suresh M Ganesan
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Marcus CS Lee
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
- Division of Infectious Diseases, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Jacquin C Niles
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Komaki-Yasuda K, Okuwaki M, Nagata K, Kawazu SI, Kano S. Identification of a novel and unique transcription factor in the intraerythrocytic stage of Plasmodium falciparum. PLoS One 2013; 8:e74701. [PMID: 24040327 PMCID: PMC3764013 DOI: 10.1371/journal.pone.0074701] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 08/03/2013] [Indexed: 11/18/2022] Open
Abstract
The mechanisms of stage-specific gene regulation in the malaria parasite Plasmodium falciparum are largely unclear, with only a small number of specific regulatory transcription factors (AP2 family) having been identified. In particular, the transcription factors that function in the intraerythrocytic stage remain to be elucidated. Previously, as a model case for stage-specific transcription in the P. falciparum intraerythrocytic stage, we analyzed the transcriptional regulation of pf1-cys-prx, a trophozoite/schizont-specific gene, and suggested that some nuclear factors bind specifically to the cis-element of pf1-cys-prx and enhance transcription. In the present study, we purified nuclear factors from parasite nuclear extract by 5 steps of chromatography, and identified a factor termed PREBP. PREBP is not included in the AP2 family, and is a novel protein with four K-homology (KH) domains. The KH domain is known to be found in RNA-binding or single-stranded DNA-binding proteins. PREBP is well conserved in Plasmodium species and partially conserved in phylum Apicomplexa. To evaluate the effects of PREBP overexpression, we used a transient overexpression and luciferase assay combined approach. Overexpression of PREBP markedly enhanced luciferase expression under the control of the pf1-cys-prx cis-element. These results provide the first evidence of a novel transcription factor that activates the gene expression in the malaria parasite intraerythrocytic stage. These findings enhance our understanding of the evolution of specific transcription machinery in Plasmodium and other eukaryotes.
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Affiliation(s)
- Kanako Komaki-Yasuda
- Research Institute, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo, Japan
- * E-mail:
| | - Mitsuru Okuwaki
- Graduate School of Comprehensive Human Sciences and Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, Japan
| | - Kyosuke Nagata
- Graduate School of Comprehensive Human Sciences and Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, Japan
| | - Shin-ichiro Kawazu
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
| | - Shigeyuki Kano
- Research Institute, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo, Japan
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A quantitative analysis of Plasmodium falciparum transfection using DNA-loaded erythrocytes. Mol Biochem Parasitol 2013; 187:117-20. [PMID: 23313825 DOI: 10.1016/j.molbiopara.2013.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 01/02/2013] [Accepted: 01/04/2013] [Indexed: 11/20/2022]
Abstract
Genetic modification of Plasmodium falciparum is a key molecular tool for the investigation of the biology and pathogenesis of this important human pathogen. The most effective means to introduce exogenous DNA into P. falciparum is via passive uptake following invasion into a DNA-loaded erythrocyte. Using bioluminescence as a tool to quantify transfection efficiency, parameters previously judged empirically to enhance transfection efficiency were subjected to a quantitative analysis. This report supports roles for fresh erythrocytes and growth medium supplemented with human serum in enhancing transfection efficiency. Critically, a proposed enhancement to transfection efficiency through continued feeding with DNA-loaded erythrocytes is not borne out in this study, and actually appears to be detrimental.
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Determination of protein subcellular localization in apicomplexan parasites. Trends Parasitol 2012; 28:546-54. [PMID: 22995720 DOI: 10.1016/j.pt.2012.08.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 08/22/2012] [Accepted: 08/24/2012] [Indexed: 11/20/2022]
Abstract
Parasites from the phylum Apicomplexa include causative agents of serious diseases including malaria (Plasmodium spp.) and toxoplasmosis (Toxoplasma gondii). Apicomplexan parasites infect thousands of types of animal cells and send their proteins to an array of compartments within their own cell, as well as exporting proteins into and beyond their host cell. Ascertaining destinations to which individual proteins are delivered allows researchers to better understand parasite biology and to identify potential targets for therapeutic interventions. Our toolkit for establishing subcellular locations of apicomplexan proteins is becoming more extensive and specialized, and here we review developments in this technology.
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