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Bravo A, Sánchez R, Zambrano F, Uribe P. Exogenous Oxidative Stress in Human Spermatozoa Induces Opening of the Mitochondrial Permeability Transition Pore: Effect on Mitochondrial Function, Sperm Motility and Induction of Cell Death. Antioxidants (Basel) 2024; 13:739. [PMID: 38929178 PMCID: PMC11201210 DOI: 10.3390/antiox13060739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 05/28/2024] [Accepted: 05/29/2024] [Indexed: 06/28/2024] Open
Abstract
Oxidative stress (OS) and disrupted antioxidant defense mechanisms play a pivotal role in the etiology of male infertility. The alterations in reactive oxygen species (ROS) production and calcium (Ca2+) homeostasis are the main activators for the mitochondrial permeability transition pore (mPTP) opening. The mPTP opening is one of the main mechanisms involved in mitochondrial dysfunction in spermatozoa. This alteration in mitochondrial function adversely affects energy supply, sperm motility, and fertilizing capacity and contributes to the development of male infertility. In human spermatozoa, the mPTP opening has been associated with ionomycin-induced endogenous oxidative stress and peroxynitrite-induced nitrosative stress; however, the effect of exogenous oxidative stress on mPTP opening in sperm has not been evaluated. The aim of this study was to determine the effect of exogenous oxidative stress induced by hydrogen peroxide (H2O2) on mPTP opening, mitochondrial function, motility, and cell death markers in human spermatozoa. Human spermatozoa were incubated with 3 mmol/L of H2O2 for 60 min, and intracellular Ca2+ concentration, mPTP opening, mitochondrial membrane potential (ΔΨm), ATP levels, mitochondrial reactive oxygen species (mROS) production, phosphatidylserine (PS) externalization, DNA fragmentation, viability, and sperm motility were evaluated. H2O2-induced exogenous oxidative stress caused increased intracellular Ca2+, leading to subsequent mPTP opening and alteration of mitochondrial function, characterized by ΔΨm dissipation, decreased ATP levels, increased mROS production, and the subsequent alteration of sperm motility. Furthermore, H2O2-induced opening of mPTP was associated with the expression of apoptotic cell death markers including PS externalization and DNA fragmentation. These results highlight the role of exogenous oxidative stress in causing mitochondrial dysfunction, deterioration of sperm motility, and an increase in apoptotic cell death markers, including PS externalization and DNA fragmentation, through the mPTP opening. This study yielded new knowledge regarding the effects of this type of stress on mitochondrial function and specifically on mPTP opening, factors that can contribute to the development of male infertility, considering that the role of mPTP in mitochondrial dysfunction in human sperm is not completely elucidated. Therefore, these findings are relevant to understanding male infertility and may provide an in vitro model for further research aimed at improving human sperm quality.
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Affiliation(s)
- Anita Bravo
- Center of Translational Medicine-Scientific and Technological Bioresource Nucleus (CEMT-BIOREN), Faculty of Medicine, Universidad de La Frontera, Temuco 4810296, Chile; (A.B.); (R.S.); (F.Z.)
| | - Raúl Sánchez
- Center of Translational Medicine-Scientific and Technological Bioresource Nucleus (CEMT-BIOREN), Faculty of Medicine, Universidad de La Frontera, Temuco 4810296, Chile; (A.B.); (R.S.); (F.Z.)
- Department of Preclinical Science, Faculty of Medicine, Universidad de La Frontera, Temuco 4781176, Chile
| | - Fabiola Zambrano
- Center of Translational Medicine-Scientific and Technological Bioresource Nucleus (CEMT-BIOREN), Faculty of Medicine, Universidad de La Frontera, Temuco 4810296, Chile; (A.B.); (R.S.); (F.Z.)
- Department of Preclinical Science, Faculty of Medicine, Universidad de La Frontera, Temuco 4781176, Chile
| | - Pamela Uribe
- Center of Translational Medicine-Scientific and Technological Bioresource Nucleus (CEMT-BIOREN), Faculty of Medicine, Universidad de La Frontera, Temuco 4810296, Chile; (A.B.); (R.S.); (F.Z.)
- Department of Internal Medicine, Faculty of Medicine, Universidad de La Frontera, Temuco 4781176, Chile
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2
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Desai SA. Novel Ion Channel Genes in Malaria Parasites. Genes (Basel) 2024; 15:296. [PMID: 38540355 PMCID: PMC10970509 DOI: 10.3390/genes15030296] [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: 02/05/2024] [Revised: 02/19/2024] [Accepted: 02/23/2024] [Indexed: 06/14/2024] Open
Abstract
Ion channels serve many cellular functions including ion homeostasis, volume regulation, signaling, nutrient acquisition, and developmental progression. Although the complex life cycles of malaria parasites necessitate ion and solute flux across membranes, the whole-genome sequencing of the human pathogen Plasmodium falciparum revealed remarkably few orthologs of known ion channel genes. Contrasting with this, biochemical studies have implicated the channel-mediated flux of ions and nutritive solutes across several membranes in infected erythrocytes. Here, I review advances in the cellular and molecular biology of ion channels in malaria parasites. These studies have implicated novel parasite genes in the formation of at least two ion channels, with additional ion channels likely present in various membranes and parasite stages. Computational approaches that rely on homology to known channel genes from higher organisms will not be very helpful in identifying the molecular determinants of these activities. Given their unusual properties, novel molecular and structural features, and essential roles in pathogen survival and development, parasite channels should be promising targets for therapy development.
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Affiliation(s)
- Sanjay A Desai
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
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3
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Basco LK. Cultivation of Asexual Intraerythrocytic Stages of Plasmodium falciparum. Pathogens 2023; 12:900. [PMID: 37513747 PMCID: PMC10384318 DOI: 10.3390/pathogens12070900] [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: 05/17/2023] [Revised: 06/22/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
Successfully developed in 1976, the continuous in vitro culture of Plasmodium falciparum has many applications in the field of malaria research. It has become an important experimental model that directly uses a human pathogen responsible for a high prevalence of morbidity and mortality in many parts of the world and is a major source of biological material for immunological, biochemical, molecular, and pharmacological studies. Until present, the basic techniques described by Trager and Jensen and Haynes et al. remain unchanged in many malaria research laboratories. Nonetheless, different factors, including culture media, buffers, serum substitutes and supplements, sources of erythrocytes, and conditions of incubation (especially oxygen concentration), have been modified by different investigators to adapt the original technique in their laboratories or enhance the in vitro growth of the parasites. The possible effects and benefits of these modifications for the continuous cultivation of asexual intraerythrocytic stages of P. falciparum, as well as future challenges in developing a serum-free cultivation system and axenic cultures, are discussed.
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Affiliation(s)
- Leonardo K Basco
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique-Hôpitaux de Marseille (AP-HM), Service de Santé des Armées (SSA), Unité Mixte de Recherche (UMR) Vecteurs-Infections Tropicales et Méditerranéennes (VITROME), 13005 Marseille, France
- Institut Hospitalo-Universitaire-Méditerranée Infection, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
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Abstract
Human malaria, caused by infection with Plasmodium parasites, remains one of the most important global public health problems, with the World Health Organization reporting more than 240 million cases and 600,000 deaths annually as of 2020 (World malaria report 2021). Our understanding of the biology of these parasites is critical for development of effective therapeutics and prophylactics, including both antimalarials and vaccines. Plasmodium is a protozoan organism that is intracellular for most of its life cycle. However, to complete its complex life cycle and to allow for both amplification and transmission, the parasite must egress out of the host cell in a highly regulated manner. This review discusses the major pathways and proteins involved in the egress events during the Plasmodium life cycle-merozoite and gametocyte egress out of red blood cells, sporozoite egress out of the oocyst, and merozoite egress out of the hepatocyte. The similarities, as well as the differences, between the various egress pathways of the parasite highlight both novel cell biology and potential therapeutic targets to arrest its life cycle.
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Affiliation(s)
- Jeffrey D Dvorin
- Division of Infectious Diseases, Boston Children's Hospital, Boston, Massachusetts, USA;
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Daniel E Goldberg
- Division of Infectious Diseases, Department of Medicine; and Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA;
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Wunderlich J. Updated List of Transport Proteins in Plasmodium falciparum. Front Cell Infect Microbiol 2022; 12:926541. [PMID: 35811673 PMCID: PMC9263188 DOI: 10.3389/fcimb.2022.926541] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
Malaria remains a leading cause of death and disease in many tropical and subtropical regions of the world. Due to the alarming spread of resistance to almost all available antimalarial drugs, novel therapeutic strategies are urgently needed. As the intracellular human malaria parasite Plasmodium falciparum depends entirely on the host to meet its nutrient requirements and the majority of its transmembrane transporters are essential and lack human orthologs, these have often been suggested as potential targets of novel antimalarial drugs. However, membrane proteins are less amenable to proteomic tools compared to soluble parasite proteins, and have thus not been characterised as well. While it had been proposed that P. falciparum had a lower number of transporters (2.5% of its predicted proteome) in comparison to most reference genomes, manual curation of information from various sources led to the identification of 197 known and putative transporter genes, representing almost 4% of all parasite genes, a proportion that is comparable to well-studied metazoan species. This transporter list presented here was compiled by collating data from several databases along with extensive literature searches, and includes parasite-encoded membrane-resident/associated channels, carriers, and pumps that are located within the parasite or exported to the host cell. It provides updated information on the substrates, subcellular localisation, class, predicted essentiality, and the presence or absence of human orthologs of P. falciparum transporters to quickly identify essential proteins without human orthologs for further functional characterisation and potential exploitation as novel drug targets.
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Affiliation(s)
- Juliane Wunderlich
- Max Planck Institute for Infection Biology, Berlin, Germany
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- *Correspondence: Juliane Wunderlich,
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PfMDR1 Transport Rates Assessed in Intact Isolated Plasmodium falciparum Digestive Vacuoles Reflect Functional Drug Resistance Relationship with pfmdr1 Mutations. Pharmaceuticals (Basel) 2022; 15:ph15020202. [PMID: 35215316 PMCID: PMC8875337 DOI: 10.3390/ph15020202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 01/28/2022] [Accepted: 02/01/2022] [Indexed: 02/07/2023] Open
Abstract
Drug resistance often emerges from mutations in solute transporters. Single amino acid exchanges may alter functionality of transporters with ‘de novo’ ability to transport drugs away from their site of action. The PfMDR1 transporter (or P-glycoprotein 1) is located in the membrane of the digestive vacuole (DV), functions as an ATP-dependent pump, and transports substrates into the DV. In this study, four strains of Plasmodium falciparum, carrying various pfmdr1 gene mutations, were analysed for their transport characteristics of Fluo-4 in isolated DVs of parasites. To obtain quantitative estimates for PfMDR1 DV surface expression, PfMDR1 protein amounts on each strain’s DV membrane were evaluated by quantitative ELISA. Fluo-4, acting as a substrate for PfMDR1, was applied in DV uptake assays (‘reverse Ca2+ imaging’). Viable DVs were isolated from trophozoite stages with preserved PfMDR1 activity. This newly developed assay enabled us to measure the number of Fluo-4 molecules actively transported into isolated DVs per PfMDR1 molecule. The drug-resistant strain Dd2 presented the highest transport rates, followed by K1 and the drug-sensitive strain 3D7, compatible with their copy numbers. With this assay, an evaluation of the probability of resistance formation for newly developed drugs can be implemented in early stages of drug development.
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Chia W, Gomez-Lorenzo MG, Castellote I, Tong JX, Chandramohanadas R, Thu Chu TT, Shen W, Go ML, de Cozar C, Crespo B, Almela MJ, Neria-Serrano F, Franco V, Gamo FJ, Tan KSW. High-Content Phenotypic Screen of a Focused TCAMS Drug Library Identifies Novel Disruptors of the Malaria Parasite Calcium Dynamics. ACS Chem Biol 2021; 16:2348-2372. [PMID: 34609851 DOI: 10.1021/acschembio.1c00512] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The search for new antimalarial drugs with unexplored mechanisms of action is currently one of the main objectives to combat the resistance already in the clinic. New drugs should target specific mechanisms that once initiated lead inevitably to the parasite's death and clearance and cause minimal toxicity to the host. One such new mode of action recently characterized is to target the parasite's calcium dynamics. Disruption of the calcium homeostasis is associated with compromised digestive vacuole membrane integrity and release of its contents, leading to programmed cell death-like features characterized by loss of mitochondrial membrane potential and DNA degradation. Intriguingly, chloroquine (CQ)-treated parasites were previously reported to exhibit such cellular features. Using a high-throughput phenotypic screen, we identified 158 physiological disruptors (hits) of parasite calcium distribution from a small subset of approximately 3000 compounds selected from the GSK TCAMS (Tres Cantos Anti-Malarial Set) compound library. These compounds were then extensively profiled for biological activity against various CQ- and artemisinin-resistant Plasmodium falciparum strains and stages. The hits were also examined for cytotoxicity, speed of antimalarial activity, and their possible inhibitory effects on heme crystallization. Overall, we identified three compounds, TCMDC-136230, -125431, and -125457, which were potent in inducing calcium redistribution but minimally inhibited heme crystallization. Molecular superimposition of the molecules by computational methods identified a common pharmacophore, with the best fit assigned to TCMDC-125457. There were low cytotoxicity or CQ cross-resistance issues for these three compounds. IC50 values of these three compounds were in the low micromolar range. In addition, TCMDC-125457 demonstrated high efficacy when pulsed in a single-dose combination with artesunate against tightly synchronized artemisinin-resistant ring-stage parasites. These results should add new drug options to the current armament of antimalarial drugs as well as provide promising starting points for development of drugs with non-classical modes of action.
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Affiliation(s)
- Wanni Chia
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, and Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, S117545, Singapore
| | - Maria G. Gomez-Lorenzo
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Isabel Castellote
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Jie Xin Tong
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, and Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, S117545, Singapore
| | - Rajesh Chandramohanadas
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, and Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, S117545, Singapore
| | - Trang Thi Thu Chu
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, and Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, S117545, Singapore
| | - Wanxiang Shen
- Department of Pharmacy, National University of Singapore, 18 Science Drive 4, S117543, Singapore
| | - Mei Lin Go
- Department of Pharmacy, National University of Singapore, 18 Science Drive 4, S117543, Singapore
| | - Cristina de Cozar
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Benigno Crespo
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Maria J. Almela
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Fernando Neria-Serrano
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Virginia Franco
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Francisco-Javier Gamo
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Kevin S. W. Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, and Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, S117545, Singapore
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de Oliveira LS, Alborghetti MR, Carneiro RG, Bastos IMD, Amino R, Grellier P, Charneau S. Calcium in the Backstage of Malaria Parasite Biology. Front Cell Infect Microbiol 2021; 11:708834. [PMID: 34395314 PMCID: PMC8355824 DOI: 10.3389/fcimb.2021.708834] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/14/2021] [Indexed: 12/26/2022] Open
Abstract
The calcium ion (Ca2+) is a ubiquitous second messenger involved in key biological processes in prokaryotes and eukaryotes. In Plasmodium species, Ca2+ signaling plays a central role in the parasite life cycle. It has been associated with parasite development, fertilization, locomotion, and host cell infection. Despite the lack of a canonical inositol-1,4,5-triphosphate receptor gene in the Plasmodium genome, pharmacological evidence indicates that inositol-1,4,5-triphosphate triggers Ca2+ mobilization from the endoplasmic reticulum. Other structures such as acidocalcisomes, food vacuole and mitochondria are proposed to act as supplementary intracellular Ca2+ reservoirs. Several Ca2+-binding proteins (CaBPs) trigger downstream signaling. Other proteins with no EF-hand motifs, but apparently involved with CaBPs, are depicted as playing an important role in the erythrocyte invasion and egress. It is also proposed that a cross-talk among kinases, which are not members of the family of Ca2+-dependent protein kinases, such as protein kinases G, A and B, play additional roles mediated indirectly by Ca2+ regulation. This statement may be extended for proteins directly related to invasion or egress, such as SUB1, ERC, IMC1I, IMC1g, GAP45 and EBA175. In this review, we update our understanding of aspects of Ca2+-mediated signaling correlated to the developmental stages of the malaria parasite life cycle.
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Affiliation(s)
- Lucas Silva de Oliveira
- Laboratory of Biochemistry and Protein Chemistry, Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
- UMR 7245 MCAM, Molécules de Communication et Adaptation des Micro-organismes, Muséum National d’Histoire Naturelle, CNRS, Équipe Parasites et Protistes Libres, Paris, France
| | - Marcos Rodrigo Alborghetti
- Laboratory of Biochemistry and Protein Chemistry, Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Brazil
| | - Renata Garcia Carneiro
- Laboratory of Biochemistry and Protein Chemistry, Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
| | - Izabela Marques Dourado Bastos
- Laboratory of Host-Pathogen Interaction, Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
| | - Rogerio Amino
- Unité Infection et Immunité Paludéennes, Institut Pasteur, Paris, France
| | - Philippe Grellier
- UMR 7245 MCAM, Molécules de Communication et Adaptation des Micro-organismes, Muséum National d’Histoire Naturelle, CNRS, Équipe Parasites et Protistes Libres, Paris, France
| | - Sébastien Charneau
- Laboratory of Biochemistry and Protein Chemistry, Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
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Broichhagen J, Kilian N. Chemical Biology Tools To Investigate Malaria Parasites. Chembiochem 2021; 22:2219-2236. [PMID: 33570245 PMCID: PMC8360121 DOI: 10.1002/cbic.202000882] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/10/2021] [Indexed: 02/06/2023]
Abstract
Parasitic diseases like malaria tropica have been shaping human evolution and history since the beginning of mankind. After infection, the response of the human host ranges from asymptomatic to severe and may culminate in death. Therefore, proper examination of the parasite's biology is pivotal to deciphering unique molecular, biochemical and cell biological processes, which in turn ensure the identification of treatment strategies, such as potent drug targets and vaccine candidates. However, implementing molecular biology methods for genetic manipulation proves to be difficult for many parasite model organisms. The development of fast and straightforward applicable alternatives, for instance small-molecule probes from the field of chemical biology, is essential. In this review, we will recapitulate the highlights of previous molecular and chemical biology approaches that have already created insight and understanding of the malaria parasite Plasmodium falciparum. We discuss current developments from the field of chemical biology and explore how their application could advance research into this parasite in the future. We anticipate that the described approaches will help to close knowledge gaps in the biology of P. falciparum and we hope that researchers will be inspired to use these methods to gain knowledge - with the aim of ending this devastating disease.
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Affiliation(s)
- Johannes Broichhagen
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP)Robert-Roessle-Strasse 1013125BerlinGermany
| | - Nicole Kilian
- Centre for Infectious DiseasesParasitologyHeidelberg University HospitalIm Neuenheimer Feld 32469120HeidelbergGermany
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Fraser M, Matuschewski K, Maier AG. Of membranes and malaria: phospholipid asymmetry in Plasmodium falciparum-infected red blood cells. Cell Mol Life Sci 2021; 78:4545-4561. [PMID: 33713154 PMCID: PMC11071739 DOI: 10.1007/s00018-021-03799-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/04/2021] [Accepted: 02/23/2021] [Indexed: 11/29/2022]
Abstract
Malaria is a vector-borne parasitic disease with a vast impact on human history, and according to the World Health Organisation, Plasmodium parasites still infect over 200 million people per year. Plasmodium falciparum, the deadliest parasite species, has a remarkable ability to undermine the host immune system and cause life-threatening disease during blood infection. The parasite's host cells, red blood cells (RBCs), generally maintain an asymmetric distribution of phospholipids in the two leaflets of the plasma membrane bilayer. Alterations to this asymmetry, particularly the exposure of phosphatidylserine (PS) in the outer leaflet, can be recognised by phagocytes. Because of the importance of innate immune defence numerous studies have investigated PS exposure in RBCs infected with P. falciparum, but have reached different conclusions. Here we review recent advancements in our understanding of the molecular mechanisms which regulate asymmetry in RBCs, and whether infection with the P. falciparum parasite results in changes to PS exposure. On the balance of evidence, it is likely that membrane asymmetry is disrupted in parasitised RBCs, though some methodological issues need addressing. We discuss the potential causes and consequences of altered asymmetry in parasitised RBCs, particularly for in vivo interactions with the immune system, and the role of host-parasite co-evolution. We also examine the potential asymmetric state of parasite membranes and summarise current knowledge on the parasite proteins, which could regulate asymmetry in these membranes. Finally, we highlight unresolved questions at this time and the need for interdisciplinary approaches to uncover the machinery which enables P. falciparum parasites to hide in mature erythrocytes.
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Affiliation(s)
- Merryn Fraser
- Research School of Biology, The Australian National University, Canberra, Australia
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, Germany
| | - Kai Matuschewski
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, Germany
| | - Alexander G Maier
- Research School of Biology, The Australian National University, Canberra, Australia.
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11
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Bobkov YV, Walker Iii WB, Cattaneo AM. Altered functional properties of the codling moth Orco mutagenized in the intracellular loop-3. Sci Rep 2021; 11:3893. [PMID: 33594162 PMCID: PMC7887336 DOI: 10.1038/s41598-021-83024-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 01/27/2021] [Indexed: 12/04/2022] Open
Abstract
Amino acid substitutions within the conserved polypeptide sequence of the insect olfactory receptor co-receptor (Orco) have been demonstrated to influence its pharmacological properties. By sequence analysis and phylogenetic investigation, in the Lepidopteran subgroup Ditrysia we identified a fixed substitution in the intracellular loop-3 (ICL-3) of a conserved histidine to glutamine. By means of HEK293 cells as a heterologous system, we functionally expressed Orco from the Ditrysian model Cydia pomonella (CpomOrco) and compared its functional properties with a site-directed mutagenized version where this ICL-3-glutamine was reverted to histidine (CpomOrcoQ417H). The mutagenized CpomOrcoQ417H displayed decreased responsiveness to VUAA1 and reduced response efficacy to an odorant agonist was observed, when co-transfected with the respective OR subunit. Evidence of reduced responsiveness and sensitivity to ligands for the mutagenized Orco suggest the fixed glutamine substitution to be optimized for functionality of the cation channel within Ditrysia. In addition, contrary to the wild type, the mutagenized CpomOrcoQ417H preserved characteristics of VUAA-binding when physiologic conditions turned to acidic. Taken together, our findings provide further evidence of the importance of ICL-3 in forming basic functional properties of insect Orco- and Orco/OR-channels, and suggest involvement of ICL-3 in the potential functional adaptation of Ditrysian Orcos to acidified extra-/intracellular environment.
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Affiliation(s)
- Yuriy V Bobkov
- Whitney Laboratory, Center for Smell and Taste, and McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - William B Walker Iii
- Department of Plant Protection Biology, Chemical Ecology Unit, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Alberto Maria Cattaneo
- Whitney Laboratory, Center for Smell and Taste, and McKnight Brain Institute, University of Florida, Gainesville, FL, USA. .,Department of Plant Protection Biology, Chemical Ecology Unit, Swedish University of Agricultural Sciences, Alnarp, Sweden.
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12
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Fraser M, Jing W, Bröer S, Kurth F, Sander LE, Matuschewski K, Maier AG. Breakdown in membrane asymmetry regulation leads to monocyte recognition of P. falciparum-infected red blood cells. PLoS Pathog 2021; 17:e1009259. [PMID: 33600495 PMCID: PMC7891792 DOI: 10.1371/journal.ppat.1009259] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/28/2020] [Indexed: 02/06/2023] Open
Abstract
The human malaria parasite Plasmodium falciparum relies on lipids to survive; this makes its lipid metabolism an attractive drug target. The lipid phosphatidylserine (PS) is usually confined to the inner leaflet of the red blood cell membrane (RBC) bilayer; however, some studies suggest that infection with the intracellular parasite results in the presence of this lipid in the RBC membrane outer leaflet, where it could act as a recognition signal to phagocytes. Here, we used fluorescent lipid analogues and probes to investigate the enzymatic reactions responsible for maintaining asymmetry between membrane leaflets, and found that in parasitised RBCs the maintenance of membrane asymmetry was partly disrupted, and PS was increased in the outer leaflet. We examined the underlying causes for the differences between uninfected and infected RBCs using fluorescent dyes and probes, and found that calcium levels increased in the infected RBC cytoplasm, whereas membrane cholesterol was depleted from the erythrocyte plasma membrane. We explored the resulting effect of PS exposure on enhanced phagocytosis by monocytes, and show that infected RBCs must expend energy to limit phagocyte recognition, and provide experimental evidence that PS exposure contributes to phagocytic recognition of P. falciparum-infected RBCs. Together, these findings underscore the pivotal role for PS exposure on the surface of Plasmodium falciparum-infected erythrocytes for in vivo interactions with the host immune system, and provide a rationale for targeted antimalarial drug design.
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Affiliation(s)
- Merryn Fraser
- Research School of Biology, The Australian National University, Canberra, Australia
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, Germany
| | - Weidong Jing
- Research School of Biology, The Australian National University, Canberra, Australia
| | - Stefan Bröer
- Research School of Biology, The Australian National University, Canberra, Australia
| | - Florian Kurth
- Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, Germany
- Department of Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
| | - Leif-Erik Sander
- Department of Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin, Germany
| | - Kai Matuschewski
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Berlin, Germany
| | - Alexander G. Maier
- Research School of Biology, The Australian National University, Canberra, Australia
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13
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Brochet M, Balestra AC, Brusini L. cGMP homeostasis in malaria parasites-The key to perceiving and integrating environmental changes during transmission to the mosquito. Mol Microbiol 2020; 115:829-838. [PMID: 33112460 DOI: 10.1111/mmi.14633] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 12/22/2022]
Abstract
Malaria-causing parasites are transmitted from humans to mosquitoes when developmentally arrested gametocytes are taken up by a female Anopheles during a blood meal. The changes in environment from human to mosquito activate gametogenesis, including a drop in temperature, a rise in pH, and a mosquito-derived molecule, xanthurenic acid. Signaling receptors have not been identified in malaria parasites but mounting evidence indicates that cGMP homeostasis is key to sensing extracellular cues in gametocytes. Low levels of cGMP maintained by phosphodiesterases prevent precocious activation of gametocytes in the human blood. Upon ingestion, initiation of gametogenesis depends on the activation of a hybrid guanylyl cyclase/P4-ATPase. Elevated cGMP levels lead to the rapid mobilization of intracellular calcium that relies upon the activation of both cGMP-dependent protein kinase and phosphoinositide phospholipase C. Once calcium is released, a cascade of phosphorylation events mediated by calcium-dependent protein kinases and phosphatases regulates the cellular processes required for gamete formation. cGMP signaling also triggers timely egress from the host cell at other life cycle stages of malaria parasites and in Toxoplasma gondii, a related apicomplexan parasite. This suggests that cGMP signaling is a versatile platform transducing external cues into calcium signals at important decision points in the life cycle of apicomplexan parasites.
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Affiliation(s)
- Mathieu Brochet
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Aurélia C Balestra
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Lorenzo Brusini
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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14
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Lu KY, Pasaje CFA, Srivastava T, Loiselle DR, Niles JC, Derbyshire E. Phosphatidylinositol 3-phosphate and Hsp70 protect Plasmodium falciparum from heat-induced cell death. eLife 2020; 9:e56773. [PMID: 32975513 PMCID: PMC7518890 DOI: 10.7554/elife.56773] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 09/14/2020] [Indexed: 12/12/2022] Open
Abstract
Phosphatidylinositol 3-phosphate (PI(3)P) levels in Plasmodium falciparum correlate with tolerance to cellular stresses caused by artemisinin and environmental factors. However, PI(3)P function during the Plasmodium stress response was unknown. Here, we used PI3K inhibitors and antimalarial agents to examine the importance of PI(3)P under thermal conditions recapitulating malarial fever. Live cell microscopy using chemical and genetic reporters revealed that PI(3)P stabilizes the digestive vacuole (DV) under heat stress. We demonstrate that heat-induced DV destabilization in PI(3)P-deficient P. falciparum precedes cell death and is reversible after withdrawal of the stress condition and the PI3K inhibitor. A chemoproteomic approach identified PfHsp70-1 as a PI(3)P-binding protein. An Hsp70 inhibitor and knockdown of PfHsp70-1 phenocopy PI(3)P-deficient parasites under heat shock. Furthermore, PfHsp70-1 downregulation hypersensitizes parasites to heat shock and PI3K inhibitors. Our findings underscore a mechanistic link between PI(3)P and PfHsp70-1 and present a novel PI(3)P function in DV stabilization during heat stress.
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Affiliation(s)
- Kuan-Yi Lu
- Department of Molecular Genetics and Microbiology, School of Medicine, Duke UniversityDurhamUnited States
- Department of Chemistry, Duke UniversityDurhamUnited States
| | | | | | - David R Loiselle
- Department of Pharmacology and Cancer Biology, School of Medicine, Duke UniversityDurhamUnited States
| | - Jacquin C Niles
- Department of Biological Engineering, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Emily Derbyshire
- Department of Molecular Genetics and Microbiology, School of Medicine, Duke UniversityDurhamUnited States
- Department of Chemistry, Duke UniversityDurhamUnited States
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15
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Garg R, Borbora SM, Bansia H, Rao S, Singh P, Verma R, Balaji KN, Nagaraja V. Mycobacterium tuberculosis Calcium Pump CtpF Modulates the Autophagosome in an mTOR-Dependent Manner. Front Cell Infect Microbiol 2020; 10:461. [PMID: 33042857 PMCID: PMC7525011 DOI: 10.3389/fcimb.2020.00461] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 07/28/2020] [Indexed: 12/17/2022] Open
Abstract
Calcium is a very important second messenger, whose concentration in various cellular compartments is under tight regulation. A disturbance in the levels of calcium in these compartments can play havoc in the cell, as it regulates various cellular processes by direct or indirect mechanisms. Here, we have investigated the functional importance of a calcium transporting P2A ATPase, CtpF of Mycobacterium tuberculosis (Mtb) in the pathogen's interaction with the host. Among its uncanny ways of dealing with the host with umpteen strategies for survival and persistence in humans, CtpF is identified as a new player. The levels of ctpF are upregulated in macrophage stresses like hypoxia, high nitric oxide levels and acidic pH. Using confocal microscopy and fluorimetry, we show that CtpF effluxes calcium in macrophages in early stages of Mtb infection. Downregulation of ctpF expression by conditional knockdown resulted in perturbation of host calcium levels and consequent decreased activation of mTOR. We present a mechanism how calcium efflux by the pathogen inhibits mTOR-dependent autophagy and enhances bacterial survival. Our work highlights how Mtb engages its metal efflux pumps to exploit host autophagic process for its proliferation.
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Affiliation(s)
- Rajni Garg
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.,Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Salik Miskat Borbora
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Harsh Bansia
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Sandhya Rao
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Prakruti Singh
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Rinkee Verma
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | | | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.,Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
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16
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Borges-Pereira L, Thomas SJ, Dos Anjos E Silva AL, Bartlett PJ, Thomas AP, Garcia CRS. The genetic Ca 2+ sensor GCaMP3 reveals multiple Ca 2+ stores differentially coupled to Ca 2+ entry in the human malaria parasite Plasmodium falciparum. J Biol Chem 2020; 295:14998-15012. [PMID: 32848018 DOI: 10.1074/jbc.ra120.014906] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/12/2020] [Indexed: 12/31/2022] Open
Abstract
Cytosolic Ca2+ regulates multiple steps in the host-cell invasion, growth, proliferation, and egress of blood-stage Plasmodium falciparum, yet our understanding of Ca2+ signaling in this endemic malaria parasite is incomplete. By using a newly generated transgenic line of P. falciparum (PfGCaMP3) that expresses constitutively the genetically encoded Ca2+ indicator GCaMP3, we have investigated the dynamics of Ca2+ release and influx elicited by inhibitors of the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase pumps, cyclopiazonic acid (CPA), and thapsigargin (Thg). Here we show that in isolated trophozoite phase parasites: (i) both CPA and Thg release Ca2+ from intracellular stores in P. falciparum parasites; (ii) Thg is able to induce Ca2+ release from an intracellular compartment insensitive to CPA; (iii) only Thg is able to activate Ca2+ influx from extracellular media, through a mechanism resembling store-operated Ca2+ entry, typical of mammalian cells; and (iv) the Thg-sensitive Ca2+ pool is unaffected by collapsing the mitochondria membrane potential with the uncoupler carbonyl cyanide m-chlorophenyl hydrazone or the release of acidic Ca2+ stores with nigericin. These data suggest the presence of two Ca2+ pools in P. falciparum with differential sensitivity to the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase pump inhibitors, and only the release of the Thg-sensitive Ca2+ store induces Ca2+ influx. Activation of the store-operated Ca2+ entry-like Ca2+ influx may be relevant for controlling processes such as parasite invasion, egress, and development mediated by kinases, phosphatases, and proteases that rely on Ca2+ levels for their activation.
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Affiliation(s)
- Lucas Borges-Pereira
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo, Brasil; Department of Pharmacology, Physiology and Neuroscience, Rutgers University, New Jersey Medical School, Newark, New Jersey, USA
| | - Samantha J Thomas
- Department of Pharmacology, Physiology and Neuroscience, Rutgers University, New Jersey Medical School, Newark, New Jersey, USA
| | | | - Paula J Bartlett
- Department of Pharmacology, Physiology and Neuroscience, Rutgers University, New Jersey Medical School, Newark, New Jersey, USA
| | - Andrew P Thomas
- Department of Pharmacology, Physiology and Neuroscience, Rutgers University, New Jersey Medical School, Newark, New Jersey, USA.
| | - Célia R S Garcia
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, São Paulo, Brasil.
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17
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Amgalan D, Garner TP, Pekson R, Jia XF, Yanamandala M, Paulino V, Liang FG, Corbalan JJ, Lee J, Chen Y, Karagiannis GS, Sanchez LR, Liang H, Narayanagari SR, Mitchell K, Lopez A, Margulets V, Scarlata M, Santulli G, Asnani A, Peterson RT, Hazan RB, Condeelis JS, Oktay MH, Steidl U, Kirshenbaum LA, Gavathiotis E, Kitsis RN. A small-molecule allosteric inhibitor of BAX protects against doxorubicin-induced cardiomyopathy. NATURE CANCER 2020; 1:315-328. [PMID: 32776015 PMCID: PMC7413180 DOI: 10.1038/s43018-020-0039-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 01/29/2020] [Indexed: 12/27/2022]
Abstract
Doxorubicin remains an essential component of many cancer regimens, but its use is limited by lethal cardiomyopathy, which has been difficult to target, owing to pleiotropic mechanisms leading to apoptotic and necrotic cardiac cell death. Here we show that BAX is rate-limiting in doxorubicin-induced cardiomyopathy and identify a small-molecule BAX inhibitor that blocks both apoptosis and necrosis to prevent this syndrome. By allosterically inhibiting BAX conformational activation, this compound blocks BAX translocation to mitochondria, thereby abrogating both forms of cell death. When co-administered with doxorubicin, this BAX inhibitor prevents cardiomyopathy in zebrafish and mice. Notably, cardioprotection does not compromise the efficacy of doxorubicin in reducing leukemia or breast cancer burden in vivo, primarily due to increased priming of mitochondrial death mechanisms and higher BAX levels in cancer cells. This study identifies BAX as an actionable target for doxorubicin-induced cardiomyopathy and provides a prototype small-molecule therapeutic.
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Affiliation(s)
- Dulguun Amgalan
- Department of Medicine, Albert Einstein College of Medicine, Bronx NY, USA
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Thomas P Garner
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Ryan Pekson
- Department of Medicine, Albert Einstein College of Medicine, Bronx NY, USA
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Xiaotong F Jia
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Mounica Yanamandala
- Department of Medicine, Albert Einstein College of Medicine, Bronx NY, USA
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA
- Division of Cardiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Victor Paulino
- Department of Medicine, Albert Einstein College of Medicine, Bronx NY, USA
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Felix G Liang
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA
| | - J Jose Corbalan
- Department of Medicine, Albert Einstein College of Medicine, Bronx NY, USA
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Jaehoon Lee
- Department of Medicine, Albert Einstein College of Medicine, Bronx NY, USA
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Yun Chen
- Department of Medicine, Albert Einstein College of Medicine, Bronx NY, USA
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA
| | - George S Karagiannis
- Department of Anatomy & Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, USA
- Integrated Imaging Program, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Luis Rivera Sanchez
- Department of Anatomy & Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Surgery, Montefiore Medical Center, Bronx, NY, USA
| | - Huizhi Liang
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Swathi-Rao Narayanagari
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Kelly Mitchell
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Andrea Lopez
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Victoria Margulets
- Departments of Physiology and Pathophysiology and Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Manitoba, Canada
| | - Marco Scarlata
- Department of Medicine, Albert Einstein College of Medicine, Bronx NY, USA
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Gaetano Santulli
- Department of Medicine, Albert Einstein College of Medicine, Bronx NY, USA
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Aarti Asnani
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- CardioVascular Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Randall T Peterson
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Rachel B Hazan
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
- Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - John S Condeelis
- Department of Anatomy & Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, USA
- Integrated Imaging Program, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Surgery, Montefiore Medical Center, Bronx, NY, USA
- Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Maja H Oktay
- Department of Anatomy & Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, USA
- Integrated Imaging Program, Albert Einstein College of Medicine, Bronx, NY, USA
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
- Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Ulrich Steidl
- Department of Medicine, Albert Einstein College of Medicine, Bronx NY, USA
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Lorrie A Kirshenbaum
- Departments of Physiology and Pathophysiology and Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
- Institute of Cardiovascular Sciences, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, Manitoba, Canada
| | - Evripidis Gavathiotis
- Department of Medicine, Albert Einstein College of Medicine, Bronx NY, USA.
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA.
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA.
- Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA.
| | - Richard N Kitsis
- Department of Medicine, Albert Einstein College of Medicine, Bronx NY, USA.
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY, USA.
- Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY, USA.
- Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA.
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18
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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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19
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Evidence for Regulation of Hemoglobin Metabolism and Intracellular Ionic Flux by the Plasmodium falciparum Chloroquine Resistance Transporter. Sci Rep 2018; 8:13578. [PMID: 30206341 PMCID: PMC6134138 DOI: 10.1038/s41598-018-31715-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 08/22/2018] [Indexed: 11/30/2022] Open
Abstract
Plasmodium falciparum multidrug resistance constitutes a major obstacle to the global malaria elimination campaign. Specific mutations in the Plasmodium falciparum chloroquine resistance transporter (PfCRT) mediate resistance to the 4-aminoquinoline drug chloroquine and impact parasite susceptibility to several partner agents used in current artemisinin-based combination therapies, including amodiaquine. By examining gene-edited parasites, we report that the ability of the wide-spread Dd2 PfCRT isoform to mediate chloroquine and amodiaquine resistance is substantially reduced by the addition of the PfCRT L272F mutation, which arose under blasticidin selection. We also provide evidence that L272F confers a significant fitness cost to asexual blood stage parasites. Studies with amino acid-restricted media identify this mutant as a methionine auxotroph. Metabolomic analysis also reveals an accumulation of short, hemoglobin-derived peptides in the Dd2 + L272F and Dd2 isoforms, compared with parasites expressing wild-type PfCRT. Physiologic studies with the ionophores monensin and nigericin support an impact of PfCRT isoforms on Ca2+ release, with substantially reduced Ca2+ levels observed in Dd2 + L272F parasites. Our data reveal a central role for PfCRT in regulating hemoglobin catabolism, amino acid availability, and ionic balance in P. falciparum, in addition to its role in determining parasite susceptibility to heme-binding 4-aminoquinoline drugs.
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20
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Reiling SJ, Krohne G, Friedrich O, Geary TG, Rohrbach P. Chloroquine exposure triggers distinct cellular responses in sensitive versus resistant Plasmodium falciparum parasites. Sci Rep 2018; 8:11137. [PMID: 30042399 PMCID: PMC6057915 DOI: 10.1038/s41598-018-29422-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/06/2018] [Indexed: 11/25/2022] Open
Abstract
Chloroquine (CQ) treatment failure in Plasmodium falciparum parasites has been documented for decades, but the pharmacological explanation of this phenotype is not fully understood. Current concepts attribute CQ resistance to reduced accumulation of the drug at a given external CQ concentration ([CQ]ex) in resistant compared to sensitive parasites. The implication of this explanation is that the mechanisms of CQ-induced toxicity in resistant and sensitive strains are similar once lethal internal concentrations have been reached. To test this hypothesis, we investigated the mechanism of CQ-induced toxicity in CQ-sensitive (CQS) versus CQ-resistant (CQR) parasites by analyzing the time-course of cellular responses in these strains after exposure to varying [CQ]ex as determined in 72 h toxicity assays. Parasite killing was delayed in CQR parasites for up to 10 h compared to CQS parasites when exposed to equipotent [CQ]ex. In striking contrast, brief exposure (1 h) to lethal [CQ]ex in CQS but not CQR parasites caused the appearance of hitherto undescribed hemozoin (Hz)-containing compartments in the parasite cytosol. Hz-containing compartments were very rarely observed in CQR parasites even after CQ exposures sufficient to cause irreversible cell death. These findings challenge current concepts that CQ killing of malaria parasites is solely concentration-dependent, and instead suggest that CQS and CQR strains fundamentally differ in the consequences of CQ exposure.
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Affiliation(s)
- Sarah J Reiling
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue (Montréal), Québec, Canada
| | - Georg Krohne
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Oliver Friedrich
- Institute of Medical Biotechnology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Timothy G Geary
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue (Montréal), Québec, Canada
| | - Petra Rohrbach
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue (Montréal), Québec, Canada.
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21
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Bootman MD, Allman S, Rietdorf K, Bultynck G. Deleterious effects of calcium indicators within cells; an inconvenient truth. Cell Calcium 2018; 73:82-87. [DOI: 10.1016/j.ceca.2018.04.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 04/03/2018] [Accepted: 04/11/2018] [Indexed: 01/20/2023]
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22
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Kushwaha AK, Apolis L, Ito D, Desai SA. Increased Ca ++ uptake by erythrocytes infected with malaria parasites: Evidence for exported proteins and novel inhibitors. Cell Microbiol 2018; 20:e12853. [PMID: 29726084 DOI: 10.1111/cmi.12853] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/18/2018] [Accepted: 04/24/2018] [Indexed: 12/12/2022]
Abstract
Malaria parasites export many proteins into their host erythrocytes and increase membrane permeability to diverse solutes. Although most solutes use a broad-selectivity channel known as the plasmodial surface anion channel, increased Ca++ uptake is mediated by a distinct, poorly characterised mechanism that appears to be essential for the intracellular parasite. Here, we examined infected cell Ca++ uptake with a kinetic fluorescence assay and the virulent human pathogen, Plasmodium falciparum. Cell surface labelling with N-hydroxysulfosuccinimide esters revealed differing effects on transport into infected and uninfected cells, indicating that Ca++ uptake at the infected cell surface is mediated by new or altered proteins at the host membrane. Conditional knockdown of PTEX, a translocon for export of parasite proteins into the host cell, significantly reduced infected cell Ca++ permeability, suggesting involvement of parasite-encoded proteins trafficked to the host membrane. A high-throughput chemical screen identified the first Ca++ transport inhibitors active against Plasmodium-infected cells. These novel chemical scaffolds inhibit both uptake and parasite growth; improved in vitro potency at reduced free [Ca++ ] is consistent with parasite killing specifically via action on one or more Ca++ transporters. These inhibitors should provide mechanistic insights into malaria parasite Ca++ transport and may be starting points for new antimalarial drugs.
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Affiliation(s)
- Ambuj K Kushwaha
- The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Liana Apolis
- The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Daisuke Ito
- The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
| | - Sanjay A Desai
- The Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, USA
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23
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High-Content Screening of the Medicines for Malaria Venture Pathogen Box for Plasmodium falciparum Digestive Vacuole-Disrupting Molecules Reveals Valuable Starting Points for Drug Discovery. Antimicrob Agents Chemother 2018; 62:AAC.02031-17. [PMID: 29311064 DOI: 10.1128/aac.02031-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 12/20/2017] [Indexed: 02/06/2023] Open
Abstract
Plasmodium falciparum infections leading to malaria have severe clinical manifestations and high mortality rates. Chloroquine (CQ), a former mainstay of malaria chemotherapy, has been rendered ineffective due to the emergence of widespread resistance. Recent studies, however, have unveiled a novel mode of action in which low-micromolar levels of CQ permeabilized the parasite's digestive vacuole (DV) membrane, leading to calcium efflux, mitochondrial depolarization, and DNA degradation. These phenotypes implicate the DV as an alternative target of CQ and suggest that DV disruption is an attractive target for exploitation by DV-disruptive antimalarials. In the current study, high-content screening of the Medicines for Malaria Venture (MMV) Pathogen Box (2015) was performed to select compounds which disrupt the DV membrane, as measured by the leakage of intravacuolar Ca2+ using the calcium probe Fluo-4 AM. The hits were further characterized by hemozoin biocrystallization inhibition assays and dose-response half-maximal (50%) inhibitory concentration (IC50) assays across resistant and sensitive strains. Three hits, MMV676380, MMV085071, and MMV687812, were shown to demonstrate a lack of CQ cross-resistance in parasite strains and field isolates. Through systematic analyses, MMV085071 emerged as the top hit due to its rapid parasiticidal effect, low-nanomolar IC50, and good efficacy in triggering DV disruption, mitochondrial degradation, and DNA fragmentation in P. falciparum These programmed cell death (PCD)-like phenotypes following permeabilization of the DV suggests that these compounds kill the parasite by a PCD-like mechanism. From the drug development perspective, MMV085071, which was identified to be a potent DV disruptor, offers a promising starting point for subsequent hit-to-lead generation and optimization through structure-activity relationships.
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Bookwalter CS, Tay CL, McCrorie R, Previs MJ, Lu H, Krementsova EB, Fagnant PM, Baum J, Trybus KM. Reconstitution of the core of the malaria parasite glideosome with recombinant Plasmodium class XIV myosin A and Plasmodium actin. J Biol Chem 2017; 292:19290-19303. [PMID: 28978649 PMCID: PMC5702669 DOI: 10.1074/jbc.m117.813972] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 09/27/2017] [Indexed: 11/08/2022] Open
Abstract
Motility of the apicomplexan malaria parasite Plasmodium falciparum is enabled by a multiprotein glideosome complex, whose core is the class XIV myosin motor, PfMyoA, and a divergent Plasmodium actin (PfAct1). Parasite motility is necessary for host-cell invasion and virulence, but studying its molecular basis has been hampered by unavailability of sufficient amounts of PfMyoA. Here, we expressed milligram quantities of functional full-length PfMyoA with the baculovirus/Sf9 cell expression system, which required a UCS (UNC-45/CRO1/She4p) family myosin chaperone from Plasmodium spp. In addition to the known light chain myosin tail interacting protein (MTIP), we identified an essential light chain (PfELC) that co-purified with PfMyoA isolated from parasite lysates. The speed at which PfMyoA moved actin was fastest with both light chains bound, consistent with the light chain–binding domain acting as a lever arm to amplify nucleotide-dependent motions in the motor domain. Surprisingly, PfELC binding to the heavy chain required that MTIP also be bound to the heavy chain, unlike MTIP that bound the heavy chain independently of PfELC. Neither the presence of calcium nor deletion of the MTIP N-terminal extension changed the speed of actin movement. Of note, PfMyoA moved filaments formed from Sf9 cell–expressed PfAct1 at the same speed as skeletal muscle actin. Duty ratio estimates suggested that as few as nine motors can power actin movement at maximal speed, a feature that may be necessitated by the dynamic nature of Plasmodium actin filaments in the parasite. In summary, we have reconstituted the essential core of the glideosome, enabling drug targeting of both of its core components to inhibit parasite invasion.
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Affiliation(s)
- Carol S Bookwalter
- From the Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405 and
| | - Chwen L Tay
- the Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom
| | - Rama McCrorie
- the Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom
| | - Michael J Previs
- From the Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405 and
| | - Hailong Lu
- From the Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405 and
| | - Elena B Krementsova
- From the Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405 and
| | - Patricia M Fagnant
- From the Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405 and
| | - Jake Baum
- the Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom
| | - Kathleen M Trybus
- From the Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405 and
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25
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Chen L, Wu L, Yu J, Kuo CT, Jian T, Wu IC, Rong Y, Chiu DT. Highly photostable wide-dynamic-range pH sensitive semiconducting polymer dots enabled by dendronizing the near-IR emitters. Chem Sci 2017; 8:7236-7245. [PMID: 29081956 PMCID: PMC5633788 DOI: 10.1039/c7sc03448b] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/02/2017] [Indexed: 12/15/2022] Open
Abstract
One constraint of semiconducting polymer dots (Pdots), especially those with near-IR emission, is their low effective emitter ratio (∼1.5 mole percent), which limits their pH sensing performance. The other critical issue of existing Pdot-based pH sensors is their poor photostability. To address these issues, we developed a series of Pdots by dendronizing the squaraine-based pH responsive near-IR emitter, which is covalently incorporated into the polyfluorene (PFO) backbone. The fluorescence self-quenching of the NIR squaraine emitter was effectively suppressed at a high emitter concentration of 5 mole percent. Through controlling the individually incomplete energy transfer from the amorphous PFO donor to the blue β-phase PFO and NIR squaraine emitter, we obtained a ratiometric pH sensor with simultaneously improved pH sensitivity, brightness, and photostability. The Pdots showed a fast and reversible pH response over the whole biological pH range of 4.7 to 8.5. Intracellular pH mapping was successfully demonstrated using this ultra-bright and photostable Pdot-based pH indicator.
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Affiliation(s)
- L Chen
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , USA .
| | - L Wu
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , USA .
| | - J Yu
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , USA .
| | - C-T Kuo
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , USA .
| | - T Jian
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , USA .
| | - I-C Wu
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , USA .
| | - Y Rong
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , USA .
| | - D T Chiu
- Department of Chemistry , University of Washington , Seattle , Washington 98195 , USA .
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26
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Jida M, Sanchez CP, Urgin K, Ehrhardt K, Mounien S, Geyer A, Elhabiri M, Lanzer M, Davioud-Charvet E. A Redox-Active Fluorescent pH Indicator for Detecting Plasmodium falciparum Strains with Reduced Responsiveness to Quinoline Antimalarial Drugs. ACS Infect Dis 2017; 3:119-131. [PMID: 28183182 DOI: 10.1021/acsinfecdis.5b00141] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mutational changes in the Plasmodium falciparum chloroquine resistance transporter (PfCRT) have been associated with differential responses to a wide spectrum of biologically active compounds including current and former quinoline and quinoline-like antimalarial drugs. PfCRT confers altered drug responsiveness by acting as a transport system, expelling drugs from the parasite's digestive vacuole where these drugs exert, at least part of, their antiplasmodial activity. To preserve the efficacy of these invaluable drugs, novel functional tools are required for epidemiological surveys of parasite strains carrying mutant PfCRT variants and for drug development programs aimed at inhibiting or circumventing the action of PfCRT. Here we report the synthesis and characterization of a pH-sensitive fluorescent chloroquine analogue consisting of 7-chloro-N-{2-[(propan-2-yl)amino]ethyl}quinolin-4-amine functionalized with the fluorochrome 7-nitrobenzofurazan (NBD) (henceforth termed Fluo-CQ). In the parasite, Fluo-CQ accumulates in the digestive vacuole, giving rise to a strong fluorescence signal but only in parasites carrying the wild type PfCRT. In parasites carrying the mutant PfCRT, Fluo-CQ does not accumulate. The differential handling of the fluorescent probe, combined with live cell imaging, provides a diagnostic tool for quick detection of those P. falciparum strains that carry a PfCRT variant associated with altered responsiveness to quinoline and quinoline-like antimalarial drugs. In contrast to the accumulation studies, chloroquine (CQ)-resistant parasites were observed cross-resistant to Fluo-CQ when the chemical probe was tested in various CQ-sensitive and -resistant parasite strains. NBD derivatives were found to act as redox cyclers of two essential targets, using a coupled assay based on methemoglobin and the NADPH-dependent glutathione reductase (GRs) from P. falciparum. This redox activity is proposed to contribute to the dual action of Fluo-CQ on redox equilibrium and methemoglobin reduction via PfCRT-mediated drug efflux in the cytosol and then continuous redox-dependent shuttling between food vacuole and cytosol. Taking into account these physicochemical characteristics, a model was proposed to explain Fluo-CQ antimalarial effects involving the contribution of PfCRT-mediated transport, methemoglobin reduction, hematin binding, and NBD reduction activity catalyzed by PfGR in CQ-resistant versus CQ-sensitive parasites. Therefore, introduction of NBD fluorophore in drugs is not inert and should be taken into account in drug transport and imaging studies.
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Affiliation(s)
- Mouhamad Jida
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), 25 rue Becquerel, F-67087 Strasbourg, France
| | - Cecilia P. Sanchez
- Zentrum
für Infektiologie, Parasitologie, Universität Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Karène Urgin
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), 25 rue Becquerel, F-67087 Strasbourg, France
| | - Katharina Ehrhardt
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), 25 rue Becquerel, F-67087 Strasbourg, France
- Zentrum
für Infektiologie, Parasitologie, Universität Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Saravanan Mounien
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), 25 rue Becquerel, F-67087 Strasbourg, France
| | - Aurelia Geyer
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), 25 rue Becquerel, F-67087 Strasbourg, France
| | - Mourad Elhabiri
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), 25 rue Becquerel, F-67087 Strasbourg, France
| | - Michael Lanzer
- Zentrum
für Infektiologie, Parasitologie, Universität Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Elisabeth Davioud-Charvet
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), 25 rue Becquerel, F-67087 Strasbourg, France
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27
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Pegoraro S, Duffey M, Otto TD, Wang Y, Rösemann R, Baumgartner R, Fehler SK, Lucantoni L, Avery VM, Moreno-Sabater A, Mazier D, Vial HJ, Strobl S, Sanchez CP, Lanzer M. SC83288 is a clinical development candidate for the treatment of severe malaria. Nat Commun 2017; 8:14193. [PMID: 28139658 PMCID: PMC5290327 DOI: 10.1038/ncomms14193] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 12/07/2016] [Indexed: 01/11/2023] Open
Abstract
Severe malaria is a life-threatening complication of an infection with the protozoan parasite Plasmodium falciparum, which requires immediate treatment. Safety and efficacy concerns with currently used drugs accentuate the need for new chemotherapeutic options against severe malaria. Here we describe a medicinal chemistry program starting from amicarbalide that led to two compounds with optimized pharmacological and antiparasitic properties. SC81458 and the clinical development candidate, SC83288, are fast-acting compounds that can cure a P. falciparum infection in a humanized NOD/SCID mouse model system. Detailed preclinical pharmacokinetic and toxicological studies reveal no observable drawbacks. Ultra-deep sequencing of resistant parasites identifies the sarco/endoplasmic reticulum Ca2+ transporting PfATP6 as a putative determinant of resistance to SC81458 and SC83288. Features, such as fast parasite killing, good safety margin, a potentially novel mode of action and a distinct chemotype support the clinical development of SC83288, as an intravenous application for the treatment of severe malaria.
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Affiliation(s)
| | - Maëlle Duffey
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
- German Center for Infection Research (DZIF), partner site Heidelberg, 69120 Heidelberg, Germany
| | - Thomas D Otto
- Parasite Genomics, Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton CB10 1SA, UK
| | - Yulin Wang
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
- German Center for Infection Research (DZIF), partner site Heidelberg, 69120 Heidelberg, Germany
| | - Roman Rösemann
- 4SC Discovery GmbH, Am Klopferspitz 19a, 82152 Martinsried, Germany
| | | | - Stefanie K Fehler
- 4SC AG, Am Klopferspitz 19a, 82152 Martinsried, Germany
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
- German Center for Infection Research (DZIF), partner site Heidelberg, 69120 Heidelberg, Germany
| | - Leonardo Lucantoni
- Eskitis Institute for Drug Discovery, Griffith University, Don Young, Nathan Queensland 4111, Australia
| | - Vicky M Avery
- Eskitis Institute for Drug Discovery, Griffith University, Don Young, Nathan Queensland 4111, Australia
| | - Alicia Moreno-Sabater
- Sorbonne Universités, UPMC Univ Paris 06, INSERM U1135, CNRS ERL 8255, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 91 Bd de l'hôpital, F-75013 Paris, France
- AP-HP, Hôpital St Antoine, Service de Parasitologie-Mycologie, F-75012 Paris, France
| | - Dominique Mazier
- Sorbonne Universités, UPMC Univ Paris 06, INSERM U1135, CNRS ERL 8255, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), 91 Bd de l'hôpital, F-75013 Paris, France
- AP-HP, Groupe hospitalier La Pitié-Salpêtrière, Service de Parasitologie-Mycologie, F-75013 Paris, France
| | - Henri J Vial
- Dynamique des Interactions Membranaires Normales et Pathologiques, CNRS UMR 5235, Université Montpellier II, cc107, Place Eugène Bataillon, 34095 Montpellier, France
| | - Stefan Strobl
- 4SC Discovery GmbH, Am Klopferspitz 19a, 82152 Martinsried, Germany
| | - Cecilia P Sanchez
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
- German Center for Infection Research (DZIF), partner site Heidelberg, 69120 Heidelberg, Germany
| | - Michael Lanzer
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
- German Center for Infection Research (DZIF), partner site Heidelberg, 69120 Heidelberg, Germany
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28
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Schneidereit D, Vass H, Reischl B, Allen RJ, Friedrich O. Calcium Sensitive Fluorescent Dyes Fluo-4 and Fura Red under Pressure: Behaviour of Fluorescence and Buffer Properties under Hydrostatic Pressures up to 200 MPa. PLoS One 2016; 11:e0164509. [PMID: 27764134 PMCID: PMC5072694 DOI: 10.1371/journal.pone.0164509] [Citation(s) in RCA: 9] [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: 08/08/2016] [Accepted: 09/26/2016] [Indexed: 11/18/2022] Open
Abstract
The fluorescent Ca2+ sensitive dyes Fura Red (ratiometric) and Fluo-4 (non-ratiometric) are widely utilized for the optical assessment of Ca2+ fluctuations in vitro as well as in situ. The fluorescent behavior of these dyes is strongly depends on temperature, pH, ionic strength and pressure. It is crucial to understand the response of these dyes to pressure when applying calcium imaging technologies in the field of high pressure bioscience. Therefore, we use an optically accessible pressure vessel to pressurize physiological Ca2+-buffered solutions at different fixed concentrations of free Ca2+ (1 nM to 25.6 μM) and a specified dye concentration (12 μM) to pressures of 200 MPa, and record dye fluorescence intensity. Our results show that Fluo-4 fluorescence intensity is reduced by 31% per 100 MPa, the intensity of Fura Red is reduced by 10% per 100 MPa. The mean reaction volume for the dissociation of calcium from the dye molecules [Formula: see text] is determined to -17.8 ml mol-1 for Fluo-4 and -21.3 ml mol-1 for Fura Red. Additionally, a model is presented that is used to correct for pressure-dependent changes in pH and binding affinity of Ca2+ to EGTA, as well as to determine the influence of these changes on dye fluorescence.
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Affiliation(s)
- D. Schneidereit
- Institute of Medical Biotechnology, Friedrich-Alexander-University Erlangen-Nuernberg, 91052 Erlangen, Bavaria, Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nuernberg, 91052 Erlangen, Bavaria, Germany
- * E-mail:
| | - H. Vass
- School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, Scotland, United Kingdom
| | - B. Reischl
- Institute of Medical Biotechnology, Friedrich-Alexander-University Erlangen-Nuernberg, 91052 Erlangen, Bavaria, Germany
| | - R. J. Allen
- School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, Scotland, United Kingdom
| | - O. Friedrich
- Institute of Medical Biotechnology, Friedrich-Alexander-University Erlangen-Nuernberg, 91052 Erlangen, Bavaria, Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nuernberg, 91052 Erlangen, Bavaria, Germany
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29
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Abstract
Some hours after invading the erythrocytes of its human host, the malaria parasite Plasmodium falciparum induces an increase in the permeability of the erythrocyte membrane to monovalent ions. The resulting net influx of Na(+) and net efflux of K(+), down their respective concentration gradients, converts the erythrocyte cytosol from an initially high-K(+), low-Na(+) solution to a high-Na(+), low-K(+) solution. The intraerythrocytic parasite itself exerts tight control over its internal Na(+), K(+), Cl(-), and Ca(2+) concentrations and its intracellular pH through the combined actions of a range of membrane transport proteins. The molecular mechanisms underpinning ion regulation in the parasite are receiving increasing attention, not least because PfATP4, a P-type ATPase postulated to be involved in Na(+) regulation, has emerged as a potential antimalarial drug target, susceptible to inhibition by a wide range of chemically unrelated compounds.
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Affiliation(s)
- Kiaran Kirk
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia;
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30
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Kuchipudi A, Arroyo-Olarte RD, Hoffmann F, Brinkmann V, Gupta N. Optogenetic monitoring identifies phosphatidylthreonine-regulated calcium homeostasis in Toxoplasma gondii. MICROBIAL CELL 2016; 3:215-223. [PMID: 28357357 PMCID: PMC5349149 DOI: 10.15698/mic2016.05.500] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Toxoplasma gondii is an obligate intracellular parasite, which inflicts acute as well as chronic infections in a wide range of warm-blooded vertebrates. Our recent work has demonstrated the natural occurrence and autonomous synthesis of an exclusive lipid phosphatidylthreonine in T. gondii. Targeted gene disruption of phosphatidylthreonine synthase impairs the parasite virulence due to unforeseen attenuation of the consecutive events of motility, egress and invasion. However, the underlying basis of such an intriguing phenotype in the parasite mutant remains unknown. Using an optogenetic sensor (gene-encoded calcium indicator, GCaMP6s), we show that loss of phosphatidylthreonine depletes calcium stores in intracellular tachyzoites, which leads to dysregulation of calcium release into the cytosol during the egress phase of the mutant. Consistently, the parasite motility and egress phenotypes in the mutant can be entirely restored by ionophore-induced mobilization of calcium. Collectively, our results suggest a novel regulatory function of phosphatidylthreonine in calcium signaling of a prevalent parasitic protist. Moreover, our application of an optogenetic sensor to monitor subcellular calcium in a model intracellular pathogen exemplifies its wider utility to other entwined systems.
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Affiliation(s)
| | | | | | | | - Nishith Gupta
- Humboldt University, Berlin, Germany.,Max-Planck Institute for Infection Biology, Berlin, Germany
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31
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Brochet M, Billker O. Calcium signalling in malaria parasites. Mol Microbiol 2016; 100:397-408. [PMID: 26748879 DOI: 10.1111/mmi.13324] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2016] [Indexed: 12/24/2022]
Abstract
Ca(2+) is a ubiquitous intracellular messenger in malaria parasites with important functions in asexual blood stages responsible for malaria symptoms, the preceding liver-stage infection and transmission through the mosquito. Intracellular messengers amplify signals by binding to effector molecules that trigger physiological changes. The characterisation of some Ca(2+) effector proteins has begun to provide insights into the vast range of biological processes controlled by Ca(2+) signalling in malaria parasites, including host cell egress and invasion, protein secretion, motility and cell cycle regulation. Despite the importance of Ca(2+) signalling during the life cycle of malaria parasites, little is known about Ca(2+) homeostasis. Recent findings highlighted that upstream of stage-specific Ca(2+) effectors is a conserved interplay between second messengers to control critical intracellular Ca(2+) signals throughout the life cycle. The identification of the molecular mechanisms integrating stage-transcending mechanisms of Ca(2+) homeostasis in a network of stage-specific regulator and effector pathways now represents a major challenge for a meaningful understanding of Ca(2+) signalling in malaria parasites.
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Affiliation(s)
- Mathieu Brochet
- Faculty of Medicine, Department of Microbiology and Molecular Medicine, University of Geneva, 1 Rue Michel-Servet, CH-1211 Geneva 4, Switzerland.,UMR5235 CNRS-Université Montpellier 2, 34095, Montpellier, France
| | - Oliver Billker
- Wellcome Trust Sanger Institute, Malaria Programme, CB10 1SA, Hinxton, UK
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32
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Budu A, Gomes MM, Melo PM, El Chamy Maluf S, Bagnaresi P, Azevedo MF, Carmona AK, Gazarini ML. Calmidazolium evokes high calcium fluctuations in Plasmodium falciparum. Cell Signal 2015; 28:125-135. [PMID: 26689736 DOI: 10.1016/j.cellsig.2015.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 11/30/2015] [Accepted: 12/07/2015] [Indexed: 10/22/2022]
Abstract
Calcium and calmodulin (CaM) are important players in eukaryote cell signaling. In the present study, by using a knockin approach, we demonstrated the expression and localization of CaM in all erythrocytic stages of Plasmodium falciparum. Under extracellular Ca(2+)-free conditions, calmidazolium (CZ), a potent CaM inhibitor, promoted a transient cytosolic calcium ([Ca(2+)]cyt) increase in isolated trophozoites, indicating that CZ mobilizes intracellular sources of calcium. In the same extracellular Ca(2+)-free conditions, the [Ca(2+)]cyt rise elicited by CZ treatment was ~3.5 fold higher when the endoplasmic reticulum (ER) calcium store was previously depleted ruling out the mobilization of calcium from the ER by CZ. The effects of the Ca(2+)/H(+) ionophore ionomycin (ION) and the Na(+)/H(+) ionophore monensin (MON) suggest that the [Ca(2+)]cyt-increasing effect of CZ is driven by the removal of Ca(2+) from at least one Ca(2+)-CaM-related (CaMR) protein as well as by the mobilization of Ca(2+) from intracellular acidic calcium stores. Moreover, we showed that the mitochondrion participates in the sequestration of the cytosolic Ca(2+) elicited by CZ. Finally, the modulation of membrane Ca(2+) channels by CZ and thapsigargin (THG) was demonstrated. The opened channels were blocked by the unspecific calcium channel blocker Co(2+) but not by 2-APB (capacitative calcium entry inhibitor) or nifedipine (L-type Ca(2+) channel inhibitor). Taken together, the results suggested that one CaMR protein is an important modulator of calcium signaling and homeostasis during the Plasmodium intraerythrocytic cell cycle, working as a relevant intracellular Ca(2+) reservoir in the parasite.
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Affiliation(s)
- Alexandre Budu
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Mayrim M Gomes
- Departamento de Biociências, Universidade Federal de São Paulo, Santos, SP, Brazil
| | - Pollyana M Melo
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Sarah El Chamy Maluf
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Piero Bagnaresi
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Mauro F Azevedo
- Instituto de Ciências Biomédicas, Universidade de São Paulo, SP, Brazil
| | - Adriana K Carmona
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, SP, Brazil.
| | - Marcos L Gazarini
- Departamento de Biociências, Universidade Federal de São Paulo, Santos, SP, Brazil.
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33
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Lourido S, Moreno SNJ. The calcium signaling toolkit of the Apicomplexan parasites Toxoplasma gondii and Plasmodium spp. Cell Calcium 2014; 57:186-93. [PMID: 25605521 DOI: 10.1016/j.ceca.2014.12.010] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 12/15/2014] [Indexed: 12/21/2022]
Abstract
Apicomplexan parasites have complex life cycles, frequently split between different hosts and reliant on rapid responses as the parasites react to changing environmental conditions. Calcium ion (Ca(2+)) signaling is consequently essential for the cellular and developmental changes that support Apicomplexan parasitism. Apicomplexan genomes reveal a rich repertoire of genes involved in calcium signaling, although many of the genes responsible for observed physiological changes remain unknown. There is evidence, for example, for the presence of a nifedipine-sensitive calcium entry mechanism in Toxoplasma, but the molecular components involved in Ca(2+) entry in both Toxoplasma and Plasmodium, have not been identified. The major calcium stores are the endoplasmic reticulum (ER), the acidocalcisomes, and the plant-like vacuole in Toxoplasma, or the food vacuole in Plasmodium spp. Pharmacological evidence suggests that Ca(2+) release from intracellular stores may be mediated by inositol 1,4,5-trisphosphate (IP3) or cyclic ADP ribose (cADPR) although there is no molecular evidence for the presence of receptors for these second messengers in the parasites. Several Ca(2+)-ATPases are present in Apicomplexans and a putative mitochondrial Ca(2+)/H(+) exchanger has been identified. Apicomplexan genomes contain numerous genes encoding Ca(2+)-binding proteins, with the notable expansion of calcium-dependent protein kinases (CDPKs), whose study has revealed roles in gliding motility, microneme secretion, host cell invasion and egress, and parasite differentiation. Microneme secretion has also been shown to depend on the C2 domain containing protein DOC2 in both Plasmodium spp. and Toxoplasma, providing further evidence for the complex transduction of Ca(2+) signals in these organisms. The characterization of these pathways could lead to the discovery of novel drug targets and to a better understanding of the role of Ca(2+) in these parasites.
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Affiliation(s)
- Sebastian Lourido
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Silvia N J Moreno
- Center for Tropical and Emerging Global Diseases, Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA.
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Friedrich O, Reiling SJ, Wunderlich J, Rohrbach P. Assessment of Plasmodium falciparum PfMDR1 transport rates using Fluo-4. J Cell Mol Med 2014; 18:1851-62. [PMID: 24889967 PMCID: PMC4196660 DOI: 10.1111/jcmm.12313] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 03/31/2014] [Indexed: 12/18/2022] Open
Abstract
Mutations in the multidrug resistance transporter of Plasmodium falciparum PfMDR1 have been implicated to play a significant role in the emergence of worldwide drug resistance, yet the molecular and biochemical mechanisms of this transporter are not well understood. Although it is generally accepted that drug resistance in P. falciparum is partly associated with PfMDR1 transport activity situated in the membrane of the digestive vacuole, direct estimates of the pump rate of this transport process in the natural environment of the intact host–parasite system have never been analysed. The fluorochrome Fluo-4 is a well-documented surrogate substrate of PfMDR1 and has been found to accumulate by actively being transported into the digestive vacuole of several parasitic strains. In the present study, we designed an approach to use Fluo-4 fluorescence uptake as a measure of compartmental Fluo-4 concentration accumulation in the different compartments of the host–parasite system. We performed a ‘reverse Fluo-4 imaging' approach to relate fluorescence intensity to changes in dye concentration rather than Ca2+ fluctuations and were able to calculate the overall rate of transport for PfMDR1 in Dd2 parasites. With this assay, we provide a powerful method to selectively measure the effect of PfMDR1 mutations on substrate transport kinetics. This will be of high significance for future compound screening to test for new drugs in resistant P. falciparum strains.
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Affiliation(s)
- O Friedrich
- Institute of Medical Biotechnology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany; SAOT, Erlangen Graduate School of Advanced Optical Technologies, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
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Carey AF, Singer M, Bargieri D, Thiberge S, Frischknecht F, Ménard R, Amino R. Calcium dynamics of Plasmodium berghei sporozoite motility. Cell Microbiol 2014; 16:768-83. [PMID: 24617597 DOI: 10.1111/cmi.12289] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/04/2014] [Accepted: 03/06/2014] [Indexed: 11/30/2022]
Abstract
Calcium is a key signalling molecule in apicomplexan parasites and plays an important role in diverse processes including gliding motility. Gliding is essential for the malaria parasite to migrate from the skin to the liver as well as to invade host tissues and cells. Here we investigated the dynamics of intracellular Ca(2+) in the motility of Plasmodium berghei sporozoites by live imaging and flow cytometry. We found that cytosolic levels of Ca(2+) increase when sporozoites are activated in suspension, which is sufficient to induce the secretion of integrin-like adhesins that are essential for gliding motility. By increasing intracellular Ca(2+) levels artificially with an ionophore, these adhesins are secreted onto the sporozoite surface, however, the parasite is not capable of gliding. A second level of Ca(2+) modulation was observed during attachment to and detachment from a solid substrate, leading to a further increase or a decrease in the cytoplasmic levels of Ca(2+) respectively. We also observed oscillations in the intracellular Ca(2+) level during gliding. Finally, an intracellular Ca(2+) chelator, an inhibitor of phosphoinositide-specific phospholipase C (PI-PLC), and an inhibitor of the inositol triphosphate (IP3) receptor blocked the rise in intracellular Ca(2+) , adhesin secretion, and motility of activated sporozoites, indicating that intracellular stores supply Ca(2+) during sporozoite gliding. Our study indicates that a rise in intracellular Ca(2+) is necessary but not sufficient to activate gliding, that Ca(2+) levels are modulated in several ways during motility, and that a PI-PLC/IP3 pathway regulates Ca(2+) release during the process of sporozoite locomotion.
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Affiliation(s)
- Allison F Carey
- Unité de Biologie et Genétique du Paludisme, Institut Pasteur, Paris, France
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Abstract
As it grows and replicates within the erythrocytes of its host the malaria parasite takes up nutrients from the extracellular medium, exports metabolites and maintains a tight control over its internal ionic composition. These functions are achieved via membrane transport proteins, integral membrane proteins that mediate the passage of solutes across the various membranes that separate the biochemical machinery of the parasite from the extracellular environment. Proteins of this type play a key role in antimalarial drug resistance, as well as being candidate drug targets in their own right. This review provides an overview of recent work on the membrane transport biology of the malaria parasite-infected erythrocyte, encompassing both the parasite-induced changes in the membrane transport properties of the host erythrocyte and the cell physiology of the intracellular parasite itself.
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A high-content phenotypic screen reveals the disruptive potency of quinacrine and 3',4'-dichlorobenzamil on the digestive vacuole of Plasmodium falciparum. Antimicrob Agents Chemother 2013; 58:550-8. [PMID: 24217693 DOI: 10.1128/aac.01441-13] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Plasmodium falciparum is the etiological agent of malignant malaria and has been shown to exhibit features resembling programmed cell death. This is triggered upon treatment with low micromolar doses of chloroquine or other lysosomotrophic compounds and is associated with leakage of the digestive vacuole contents. In order to exploit this cell death pathway, we developed a high-content screening method to select compounds that can disrupt the parasite vacuole, as measured by the leakage of intravacuolar Ca(2+). This assay uses the ImageStream 100, an imaging-capable flow cytometer, to assess the distribution of the fluorescent calcium probe Fluo-4. We obtained two hits from a small library of 25 test compounds, quinacrine and 3',4'-dichlorobenzamil. The ability of these compounds to permeabilize the digestive vacuole in laboratory strains and clinical isolates was validated by confocal microscopy. The hits could induce programmed cell death features in both chloroquine-sensitive and -resistant laboratory strains. Quinacrine was effective at inhibiting field isolates in a 48-h reinvasion assay regardless of artemisinin clearance status. We therefore present as proof of concept a phenotypic screening method with the potential to provide mechanistic insights to the activity of antimalarial drugs.
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Li X, Gao X, Shi W, Ma H. Design strategies for water-soluble small molecular chromogenic and fluorogenic probes. Chem Rev 2013; 114:590-659. [PMID: 24024656 DOI: 10.1021/cr300508p] [Citation(s) in RCA: 1181] [Impact Index Per Article: 107.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Xiaohua Li
- Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China
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Glushakova S, Lizunov V, Blank PS, Melikov K, Humphrey G, Zimmerberg J. Cytoplasmic free Ca2+ is essential for multiple steps in malaria parasite egress from infected erythrocytes. Malar J 2013; 12:41. [PMID: 23363708 PMCID: PMC3564835 DOI: 10.1186/1475-2875-12-41] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 01/19/2013] [Indexed: 11/25/2022] Open
Abstract
Background Egress of Plasmodium falciparum, from erythrocytes at the end of its asexual cycle and subsequent parasite invasion into new host cells, is responsible for parasite dissemination in the human body. The egress pathway is emerging as a coordinated multistep programme that extends in time for tens of minutes, ending with rapid parasite extrusion from erythrocytes. While the Ca2+ regulation of the invasion of P. falciparum in erythrocytes is well established, the role of Ca2+ in parasite egress is poorly understood. This study analysed the involvement of cytoplasmic free Ca2+ in infected erythrocytes during the multistep egress programme of malaria parasites. Methods Live-cell fluorescence microscopy was used to image parasite egress from infected erythrocytes, assessing the effect of drugs modulating Ca2+ homeostasis on the egress programme. Results A steady increase in cytoplasmic free Ca2+ is found to precede parasite egress. This increase is independent of extracellular Ca2+ for at least the last two hours of the cycle, but is dependent upon Ca2+ release from internal stores. Intracellular BAPTA chelation of Ca2+ within the last 45 minutes of the cycle inhibits egress prior to parasitophorous vacuole swelling and erythrocyte membrane poration, two characteristic morphological transformations preceding parasite egress. Inhibitors of the parasite endoplasmic reticulum (ER) Ca2+-ATPase accelerate parasite egress, indicating that Ca2+ stores within the ER are sufficient in supporting egress. Markedly accelerated egress of apparently viable parasites was achieved in mature schizonts using Ca2+ ionophore A23187. Ionophore treatment overcomes the BAPTA-induced block of parasite egress, confirming that free Ca2+ is essential in egress initiation. Ionophore treatment of immature schizonts had an adverse effect inducing parasitophorous vacuole swelling and killing the parasites within the host cell. Conclusions The parasite egress programme requires intracellular free Ca2+ for egress initiation, vacuole swelling, and host cell cytoskeleton digestion. The evidence that parasitophorous vacuole swelling, a stage of unaffected egress, is dependent upon a rise in intracellular Ca2+ suggests a mechanism for ionophore-inducible egress and a new target for Ca2+ in the programme liberating parasites from the host cell. A regulatory pathway for egress that depends upon increases in intracellular free Ca2+ is proposed.
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Affiliation(s)
- Svetlana Glushakova
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, 20892, USA
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Gonçalves LCP, Tonelli RR, Bagnaresi P, Mortara RA, Ferreira AG, Bastos EL. A nature-inspired betalainic probe for live-cell imaging of Plasmodium-infected erythrocytes. PLoS One 2013; 8:e53874. [PMID: 23342028 PMCID: PMC3547039 DOI: 10.1371/journal.pone.0053874] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 12/04/2012] [Indexed: 11/24/2022] Open
Abstract
A model betalainic dye was semisynthesized from betanin, the magenta pigment of the red beet, and was effective for live-cell imaging of Plasmodium-infected red blood cells. This water-soluble fluorescent probe is photostable, excitable in the visible region and cell membrane-permeable, and its photophysical properties are not notably pH-sensitive. Fluorescence imaging microscopy of erythrocytes infected with Plasmodium falciparum, a causative agent of malaria in humans, showed that only the parasite was stained. Z-stacking analysis suggested that the probe accumulates proximal to the nucleus of the parasite. Indicaxanthin, one of the natural fluorescent betalains found in the petals of certain flowers, did not stain the parasite or the red blood cell.
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Affiliation(s)
| | - Renata Rosito Tonelli
- Departamento de Ciências Biológicas, Universidade Federal de São Paulo, Diadema, Sao Paulo, Brazil
| | - Piero Bagnaresi
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Renato Arruda Mortara
- Departamento de Microbiologia, Imunobiologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | | | - Erick Leite Bastos
- Departamento de Química Fundamental, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
- * E-mail:
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41
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Wirth CC, Pradel G. Molecular mechanisms of host cell egress by malaria parasites. Int J Med Microbiol 2012; 302:172-8. [DOI: 10.1016/j.ijmm.2012.07.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Salcedo-Sora JE, Ward SA, Biagini GA. A yeast expression system for functional and pharmacological studies of the malaria parasite Ca²⁺/H⁺ antiporter. Malar J 2012; 11:254. [PMID: 22853777 PMCID: PMC3488005 DOI: 10.1186/1475-2875-11-254] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2012] [Accepted: 07/23/2012] [Indexed: 12/26/2022] Open
Abstract
Background Calcium (Ca2+) signalling is fundamental for host cell invasion, motility, in vivo synchronicity and sexual differentiation of the malaria parasite. Consequently, cytoplasmic free Ca2+ is tightly regulated through the co-ordinated action of primary and secondary Ca2+ transporters. Identifying selective inhibitors of Ca2+ transporters is key towards understanding their physiological role as well as having therapeutic potential, therefore screening systems to facilitate the search for potential inhibitors are a priority. Here, the methodology for the expression of a Calcium membrane transporter that can be scaled to high throughputs in yeast is presented. Methods The Plasmodium falciparum Ca2+/H+ antiporter (PfCHA) was expressed in the yeast Saccharomyces cerevisiae and its activity monitored by the bioluminescence from apoaequorin triggered by divalent cations, such as calcium, magnesium and manganese. Results Bioluminescence assays demonstrated that PfCHA effectively suppressed induced cytoplasmic peaks of Ca2+, Mg2+ and Mn2+ in yeast mutants lacking the homologue yeast antiporter Vcx1p. In the scalable format of 96-well culture plates pharmacological assays with a cation antiporter inhibitor allowed the measurement of inhibition of the Ca2+ transport activity of PfCHA conveniently translated to the familiar concept of fractional inhibitory concentrations. Furthermore, the cytolocalization of this antiporter in the yeast cells showed that whilst PfCHA seems to locate to the mitochondrion of P. falciparum, in yeast PfCHA is sorted to the vacuole. This facilitates the real-time Ca2+-loading assays for further functional and pharmacological studies. Discussion The functional expression of PfCHA in S. cerevisiae and luminescence-based detection of cytoplasmic cations as presented here offer a tractable system that facilitates functional and pharmacological studies in a high-throughput format. PfCHA is shown to behave as a divalent cation/H+ antiporter susceptible to the effects of cation/H+ inhibitors such as KB-R7943. This type of gene expression systems should advance the efforts for the screening of potential inhibitors of this type of divalent cation transporters as part of the malaria drug discovery initiatives and for functional studies in general. Conclusion The expression and activity of the PfCHA detected in yeast by a bioluminescence assay that follows the levels of cytoplasmic Ca2+ as well as Mg2+ and Mn2+ lend itself to high-throughput and quantitative settings for pharmacological screening and functional studies.
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Rohrbach P. Quantitative fluorescent live cell imaging of intracellular Ca2+ and H+ ions in malaria parasites. Methods Enzymol 2012; 505:469-83. [PMID: 22289468 DOI: 10.1016/b978-0-12-388448-0.00032-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
Light microscopy plays an important role in cell biology and has been instrumental in the description of the living world. Fluorescent probes and new advances in microscopic techniques have revolutionized the application, enabling real time investigation of biological processes in 3D living cells using physiological conditions. Current applications of live cell imaging may include quantification of ion concentrations in cellular compartments, monitoring ion fluxes and signaling events, protein sorting and trafficking processes, as well as protein-protein interactions. Because of its potential, live cell imaging has been widely applied to study the biology and pathophysiology of the human malaria parasite Plasmodium falciparum. Apart from its clinical importance, P. falciparum has fascinated the cell biologist because of its ability to exist and develop within an inert cell: the human erythrocyte. Our understanding of intracellular ion regulation in malaria parasites has been greatly enhanced since the introduction of fluorescence microscopy and live cell imaging. This chapter provides an overview of the various fluorescent molecules available to monitor ion homeostasis in this parasite and outline the techniques used for ion quantification.
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Affiliation(s)
- Petra Rohrbach
- Institute of Parasitology, McGill University, Quebec, Canada
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Abstract
Calcium is relevant for several vital functions in apicomplexan parasites, including host cell invasion, parasite motility and differentiation. The ER (endoplasmic reticulum) and calcium-rich acidocalcisomes have been identified as major calcium stores. Other potential calcium-storage organelles include the Golgi, the mitochondrion, the apicoplast and the recently described plant-like vacuole in Toxoplasma gondii. Compared with most eukaryotic systems, apicomplexan parasites contain a reduced number of calcium-related genes, a vast majority of which remain uncharacterized. Several Ca²⁺-ATPases have been described in apicomplexans, several of which are annotated in the different genomes. There is experimental evidence for an IP3 (inositol 1,4,5-trisphosphate)-dependent calcium response in Plasmodium spp. and T. gondii, although no IP3 or ryanodine receptors have been identified. Genes encoding potential calcium channels are present in T. gondi, but not in Plasmodium spp. and Cryptosporidium spp. Effector calcium-binding proteins including calmodulins and CDPK (calcium-dependent protein kinase) genes mainly found in plants have also been described. The characterized CDPKs were found to play important roles in protein secretion, host cell invasion and parasite differentiation. Taken together, the available information on calcium storage and function in apicomplexans, although fragmented, suggest the existence of unique calcium-mediated pathways in these parasites. An in-depth functional characterization of the apicomplexan calcium-related genes could lead to the identification of novel therapeutic targets, and will improve our understanding of the role of calcium in parasite development and virulence.
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Generation of second messengers in Plasmodium. Microbes Infect 2012; 14:787-95. [PMID: 22584103 DOI: 10.1016/j.micinf.2012.04.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 04/17/2012] [Accepted: 04/18/2012] [Indexed: 02/05/2023]
Abstract
Signalling in malaria parasites is a field of growing interest as its components may prove to be valuable drug targets, especially when one considers the burden of a disease that is responsible for up to 500 million infections annually. The scope of this review is to discuss external stimuli in the parasite life cycle and the upstream machinery responsible for translating them into intracellular responses, focussing particularly on the calcium signalling pathway.
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Holder AA, Mohd Ridzuan MA, Green JL. Calcium dependent protein kinase 1 and calcium fluxes in the malaria parasite. Microbes Infect 2012; 14:825-30. [PMID: 22584104 DOI: 10.1016/j.micinf.2012.04.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 04/11/2012] [Accepted: 04/11/2012] [Indexed: 01/20/2023]
Abstract
Calcium dependent protein kinases (CDPKs) are found only in plants and alveolates and are distinguished from other kinases by an activation domain that binds calcium directly. Plants contain families of these kinases and their functions are modulated by post translational modifications as well as calcium activation. Apicomplexan parasites also contain CDPK families and this review is focused on CDPK1 in Plasmodium spp. This enzyme has been implicated in parasite motility and host cell invasion and at least two substrates associated with the actomyosin motor complex have been identified. By analogy with the plant CDPKs we propose that its activity is modulated both by post translational modifications and by its subcellular location in a compartment within the parasite's pellicle, which may regulate the calcium concentration required for activation.
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Affiliation(s)
- Anthony A Holder
- Division of Parasitology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK.
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Plattner H, Sehring IM, Mohamed IK, Miranda K, De Souza W, Billington R, Genazzani A, Ladenburger EM. Calcium signaling in closely related protozoan groups (Alveolata): non-parasitic ciliates (Paramecium, Tetrahymena) vs. parasitic Apicomplexa (Plasmodium, Toxoplasma). Cell Calcium 2012; 51:351-82. [PMID: 22387010 DOI: 10.1016/j.ceca.2012.01.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 01/10/2012] [Accepted: 01/12/2012] [Indexed: 12/20/2022]
Abstract
The importance of Ca2+-signaling for many subcellular processes is well established in higher eukaryotes, whereas information about protozoa is restricted. Recent genome analyses have stimulated such work also with Alveolates, such as ciliates (Paramecium, Tetrahymena) and their pathogenic close relatives, the Apicomplexa (Plasmodium, Toxoplasma). Here we compare Ca2+ signaling in the two closely related groups. Acidic Ca2+ stores have been characterized in detail in Apicomplexa, but hardly in ciliates. Two-pore channels engaged in Ca2+-release from acidic stores in higher eukaryotes have not been stingently characterized in either group. Both groups are endowed with plasma membrane- and endoplasmic reticulum-type Ca2+-ATPases (PMCA, SERCA), respectively. Only recently was it possible to identify in Paramecium a number of homologs of ryanodine and inositol 1,3,4-trisphosphate receptors (RyR, IP3R) and to localize them to widely different organelles participating in vesicle trafficking. For Apicomplexa, physiological experiments suggest the presence of related channels although their identity remains elusive. In Paramecium, IP3Rs are constitutively active in the contractile vacuole complex; RyR-related channels in alveolar sacs are activated during exocytosis stimulation, whereas in the parasites the homologous structure (inner membrane complex) may no longer function as a Ca2+ store. Scrutinized comparison of the two closely related protozoan phyla may stimulate further work and elucidate adaptation to parasitic life. See also "Conclusions" section.
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Affiliation(s)
- H Plattner
- Department of Biology, University of Konstanz, P.O. Box 5560, 78457 Konstanz, Germany.
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Cho S, Kim S, Kim Y, Park Y. Optical imaging techniques for the study of malaria. Trends Biotechnol 2011; 30:71-9. [PMID: 21930322 DOI: 10.1016/j.tibtech.2011.08.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2011] [Revised: 08/25/2011] [Accepted: 08/26/2011] [Indexed: 02/07/2023]
Abstract
Malarial infection needs to be imaged to reveal the mechanisms behind malaria pathophysiology and to provide insights to aid in the diagnosis of the disease. Recent advances in optical imaging methods are now being transferred from physics laboratories to the biological field, revolutionizing how we study malaria. To provide insight into how these imaging techniques can improve the study and treatment of malaria, we summarize recent progress on optical imaging techniques, ranging from in vitro visualization of the disease progression of malaria infected red blood cells (iRBCs) to in vivo imaging of malaria parasites in the liver.
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Affiliation(s)
- Sangyeon Cho
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon, 305-701, Republic of Korea
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Xie J, Chen Y, Yang W, Xu D, Zhang K. Water soluble 1,8-naphthalimide fluorescent pH probes and their application to bioimagings. J Photochem Photobiol A Chem 2011. [DOI: 10.1016/j.jphotochem.2011.08.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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50
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Chandramohanadas R, Park Y, Lui L, Li A, Quinn D, Liew K, Diez-Silva M, Sung Y, Dao M, Lim CT, Preiser PR, Suresh S. Biophysics of malarial parasite exit from infected erythrocytes. PLoS One 2011; 6:e20869. [PMID: 21698115 PMCID: PMC3117855 DOI: 10.1371/journal.pone.0020869] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 05/11/2011] [Indexed: 11/26/2022] Open
Abstract
Upon infection and development within human erythrocytes, P. falciparum induces alterations to the infected RBC morphology and bio-mechanical properties to eventually rupture the host cells through parasitic and host derived proteases of cysteine and serine families. We used previously reported broad-spectrum inhibitors (E64d, EGTA-AM and chymostatin) to inhibit these proteases and impede rupture to analyze mechanical signatures associated with parasite escape. Treatment of late-stage iRBCs with E64d and EGTA-AM prevented rupture, resulted in no major RBC cytoskeletal reconfiguration but altered schizont morphology followed by dramatic re-distribution of three-dimensional refractive index (3D-RI) within the iRBC. These phenotypes demonstrated several-fold increased iRBC membrane flickering. In contrast, chymostatin treatment showed no 3D-RI changes and caused elevated fluctuations solely within the parasitophorous vacuole. We show that E64d and EGTA-AM supported PV breakdown and the resulting elevated fluctuations followed non-Gaussian pattern that resulted from direct merozoite impingement against the iRBC membrane. Optical trapping experiments highlighted reduced deformability of the iRBC membranes upon rupture-arrest, more specifically in the treatments that facilitated PV breakdown. Taken together, our experiments provide novel mechanistic interpretations on the role of parasitophorous vacuole in maintaining the spherical schizont morphology, the impact of PV breakdown on iRBC membrane fluctuations leading to eventual parasite escape and the evolution of membrane stiffness properties of host cells in which merozoites were irreversibly trapped, recourse to protease inhibitors. These findings provide a comprehensive, previously unavailable, body of information on the combined effects of biochemical and biophysical factors on parasite egress from iRBCs.
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Affiliation(s)
| | - YongKeun Park
- George R. Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Lena Lui
- Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
| | - Ang Li
- Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
| | - David Quinn
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Kingsley Liew
- Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
| | - Monica Diez-Silva
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Yongjin Sung
- George R. Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Ming Dao
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | | | | | - Subra Suresh
- Singapore-MIT Alliance for Research and Technology Centre, Singapore, Singapore
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
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