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de Villiers KA, Egan TJ. Heme Detoxification in the Malaria Parasite: A Target for Antimalarial Drug Development. Acc Chem Res 2021; 54:2649-2659. [PMID: 33982570 DOI: 10.1021/acs.accounts.1c00154] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Over the last century, malaria deaths have decreased by more than 85%. Nonetheless, there were 405 000 deaths in 2018, mostly resulting from Plasmodium falciparum infection. In the 21st century, much of the advance has arisen from the deployment of insecticide-treated bed nets and artemisinin combination therapy. However, over the past few decades parasites with a delayed artemisinin clearance phenotype have appeared in Southeast Asia, threatening further gains. The effort to find new drugs is thus urgent. A prominent process in blood stage malaria parasites, which we contend remains a viable drug target, is hemozoin formation. This crystalline material consisting of heme can be readily seen when parasites are viewed microscopically. The process of its formation in the parasite, however, is still not fully understood.In early work, we recognized hemozoin formation as a biomineralization process. We have subsequently investigated the kinetics of synthetic hemozoin (β-hematin) crystallization catalyzed at lipid-aqueous interfaces under biomimetic conditions. This led us to the use of neutral detergent-based high-throughput screening (HTS) for inhibitors of β-hematin formation. A good hit rate against malaria parasites was obtained. Simultaneously, we developed a pyridine-based assay which proved successful in measuring the concentrations of hematin not converted to β-hematin.The pyridine assay was adapted to determine the effects of chloroquine and other clinical antimalarials on hemozoin formation in the cell. This permitted the determination of the dose-dependent amounts of exchangeable heme and hemozoin in P. falciparum for the first time. These studies have shown that hemozoin inhibitors cause a dose-dependent increase in exchangeable heme, correlated with decreased parasite survival. Electron spectroscopic imaging (ESI) showed a relocation of heme iron into the parasite cytoplasm, while electron microscopy provided evidence of the disruption of hemozoin crystals. This cellular assay was subsequently extended to top-ranked hits from a wide range of scaffolds found by HTS. Intriguingly, the amounts of exchangeable heme at the parasite growth IC50 values of these scaffolds showed substantial variation. The amount of exchangeable heme was found to be correlated with the amount of inhibitor accumulated in the parasitized red blood cell. This suggests that heme-inhibitor complexes, rather than free heme, lead to parasite death. This was supported by ESI using a Br-containing compound which showed the colocalization of Fe and Br as well as by confocal Raman microscopy which confirmed the presence of a complex in the parasite. Current evidence indicates that inhibitors block hemozoin formation by surface adsorption. Indeed, we have successfully introduced molecular docking with hemozoin to find new inhibitors. It follows that the resulting increase in free heme leads to the formation of the parasiticidal heme-inhibitor complex. We have reported crystal structures of heme-drug complexes for several aryl methanol antimalarials in nonaqueous media. These form coordination complexes but most other inhibitors interact noncovalently, and the determination of their structures remains a major challenge.It is our view that key future developments will include improved assays to measure cellular heme levels, better in silico approaches for predicting β-hematin inhibition, and a concerted effort to determine the structure and properties of heme-inhibitor complexes.
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Affiliation(s)
- Katherine A. de Villiers
- Department of Chemistry and Polymer Science, Stellenbosch University, Private Bag, Matieland 7600, South Africa
| | - Timothy J. Egan
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch 7701, South Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town 7945, South Africa
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The use of antimalarial plants as traditional treatment in Papua Island, Indonesia. Heliyon 2020; 6:e05562. [PMID: 33344788 PMCID: PMC7736719 DOI: 10.1016/j.heliyon.2020.e05562] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/13/2020] [Accepted: 11/17/2020] [Indexed: 11/21/2022] Open
Abstract
The residents of the Eastern part of Indonesia, specifically, Papua and West Papua provinces, are dependent on traditional medicines with the use of plants, which includes treating malaria. However, there are limited information on the diversity of medicinal plants in Papua Island. Hence, the Indonesian Ministry of Health put together a database of all the natural plant-based raw materials in Indonesia, to address part of the issues encountered as a result of the limited information on the diversity of plants. Based on this background, the aim of the research was to analyze the information on medicinal plants used by the traditional healers in Papua Island based on the results of research on medicinal plants and Jamu (RISTOJA), especially in treating malaria. Data were obtained through ethnomedicine research conducted in 2012 and 2017 involving 54 ethnicities in Papua. Based on the results, 72 species of medicinal plants from 67 genera and 40 families were used traditionally in treating malaria on Papua Island. The most common medicinal plants used as traditional antimalarial concoction are Alstonia scholaris (L.) R. Br., Carica papaya L., Andrographis paniculata (Burm. f.) Nees, and Physalis minima L. Similar to other ethnobotany research, the leaves were the most used plant parts in preparing the various traditional concoctions.
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Kostka T, Fohrer J, Guigas C, Briviba K, Seiwert N, Fahrer J, Steinberg P, Empl MT. Synthesis and in vitro characterization of the genotoxic, mutagenic and cell-transforming potential of nitrosylated heme. Arch Toxicol 2020; 94:3911-3927. [PMID: 32671443 PMCID: PMC7603461 DOI: 10.1007/s00204-020-02846-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/09/2020] [Indexed: 12/18/2022]
Abstract
Data from epidemiological studies suggest that consumption of red and processed meat is a factor contributing to colorectal carcinogenesis. Red meat contains high amounts of heme, which in turn can be converted to its nitrosylated form, NO-heme, when adding nitrite-containing curing salt to meat. NO-heme might contribute to colorectal cancer formation by causing gene mutations and could thereby be responsible for the association of (processed) red meat consumption with intestinal cancer. Up to now, neither in vitro nor in vivo studies characterizing the mutagenic and cell transforming potential of NO-heme have been published due to the fact that the pure compound is not readily available. Therefore, in the present study, an already existing synthesis protocol was modified to yield, for the first time, purified NO-heme. Thereafter, newly synthesized NO-heme was chemically characterized and used in various in vitro approaches at dietary concentrations to determine whether it can lead to DNA damage and malignant cell transformation. While NO-heme led to a significant dose-dependent increase in the number of DNA strand breaks in the comet assay and was mutagenic in the HPRT assay, this compound tested negative in the Ames test and failed to induce malignant cell transformation in the BALB/c 3T3 cell transformation assay. Interestingly, the non-nitrosylated heme control showed similar effects, but was additionally able to induce malignant transformation in BALB/c 3T3 murine fibroblasts. Taken together, these results suggest that it is the heme molecule rather than the NO moiety which is involved in driving red meat-associated carcinogenesis.
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Affiliation(s)
- Tina Kostka
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, Hannover, Germany.
- Institute of Food Science and Human Nutrition, Leibniz University Hannover, Hannover, Germany.
| | - Jörg Fohrer
- Institute of Organic Chemistry, Leibniz University Hannover, Hannover, Germany
| | - Claudia Guigas
- Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Karlsruhe, Germany
| | - Karlis Briviba
- Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Karlsruhe, Germany
| | - Nina Seiwert
- Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Jörg Fahrer
- Division of Food Chemistry and Toxicology, Department of Chemistry, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Pablo Steinberg
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, Hannover, Germany
- Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Karlsruhe, Germany
| | - Michael T Empl
- Institute for Food Toxicology, University of Veterinary Medicine Hannover, Hannover, Germany
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Chen AJ, Huang KC, Bopp S, Summers R, Dong P, Huang Y, Zong C, Wirth D, Cheng JX. Quantitative imaging of intraerythrocytic hemozoin by transient absorption microscopy. JOURNAL OF BIOMEDICAL OPTICS 2019; 25:1-11. [PMID: 31849205 PMCID: PMC6916744 DOI: 10.1117/1.jbo.25.1.014507] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 11/22/2019] [Indexed: 06/10/2023]
Abstract
Hemozoin, the heme detoxification end product in malaria parasites during their growth in the red blood cells (RBCs), serves as an important marker for diagnosis and treatment target of malaria disease. However, the current method for hemozoin-targeted drug screening mainly relies on in vitro β-hematin inhibition assays, which may lead to false-positive events due to under-representation of the real hemozoin crystal. Quantitative in situ imaging of hemozoin is highly desired for high-throughput screening of antimalarial drugs and for elucidating the mechanisms of antimalarial drugs. We present transient absorption (TA) imaging as a high-speed single-cell analysis platform with chemical selectivity to hemozoin. We first demonstrated that TA microscopy is able to identify β-hematin, the artificial form of hemozoin, from the RBCs. We further utilized time-resolved TA imaging to in situ discern hemozoin from malaria-infected RBCs with optimized imaging conditions. Finally, we quantitatively analyzed the hemozoin amount in RBCs at different infection stages by single-shot TA imaging. These results highlight the potential of TA imaging for efficient antimalarial drug screening and drug mechanism investigation.
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Affiliation(s)
- Andy J. Chen
- Purdue University, Department of Biological Sciences, West Lafayette, Indiana, United States
| | - Kai-Chih Huang
- Boston University, Photonics Center, Boston, Massachusetts, United States
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
| | - Selina Bopp
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States
| | - Robert Summers
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States
| | - Puting Dong
- Boston University, Photonics Center, Boston, Massachusetts, United States
| | - Yimin Huang
- Boston University, Photonics Center, Boston, Massachusetts, United States
| | - Cheng Zong
- Boston University, Photonics Center, Boston, Massachusetts, United States
| | - Dyann Wirth
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States
| | - Ji-Xin Cheng
- Boston University, Photonics Center, Boston, Massachusetts, United States
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Boston University, Department of Electrical and Computer Engineering, Boston, Massachusetts, United States
- Boston University, Department of Chemistry, Boston, Massachusetts, United States
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5
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Yeon C, Lee I, Kim GH, Yun SJ. Unimer-Assisted Exfoliation for Highly Concentrated Aqueous Dispersion Solutions of Single- and Few-Layered van der Waals Materials. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:1217-1226. [PMID: 28099026 DOI: 10.1021/acs.langmuir.6b04121] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We suggest a unimer-assisted exfoliation method for the exfoliation of van der Waals two-dimensional (2D) materials such as graphene, MoS2, and h-BN and show that the micellar size is a critical parameter for enhancing the exfoliation efficiency. To explain the effectiveness of the unimers in the exfoliation, the influence of the micellar size of a biocompatible block copolymer, Pluronic F-68, is evaluated in view of the yield and thickness of exfoliated 2D flakes. By the addition of water-soluble alcohols, the surfactants exist in the form of a unimer, which facilitates the intercalation into the layered materials and their exfoliation. The results showed that the high exfoliation efficiency could be achieved by controlling the micellar size mostly to be unimers; the average yield rate of MoS2 exfoliation was 4.51% per hour, and the very high concentration of 1.45 mg/mL was obtained by sonication for 3 h. We also suggested the dielectrophoresis technique as a method for forming a film composed of 2D flakes for diverse applications requiring electrical signals. The unimer-assisted exfoliation method will be substantially utilized to achieve highly concentrated aqueous dispersion solutions of 2D materials.
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Affiliation(s)
- Changbong Yeon
- ICT Materials & Components & Research Laboratory, Electronics and Telecommunications Research Institute , 218 Gajeongno, Yuseong-gu, Daejeon 305-700, Republic of Korea
- Department of Advanced Device Engineering, University of Science and Technology , 217 Gajeongno, Yuseong-gu, Daejeon 305-350, Republic of Korea
| | - Inyeal Lee
- School of Electronic and Electrical Engineering and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University , Suwon 16419, Republic of Korea
| | - Gil-Ho Kim
- School of Electronic and Electrical Engineering and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University , Suwon 16419, Republic of Korea
| | - Sun Jin Yun
- ICT Materials & Components & Research Laboratory, Electronics and Telecommunications Research Institute , 218 Gajeongno, Yuseong-gu, Daejeon 305-700, Republic of Korea
- Department of Advanced Device Engineering, University of Science and Technology , 217 Gajeongno, Yuseong-gu, Daejeon 305-350, Republic of Korea
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6
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High-Throughput Screening and Prediction Model Building for Novel Hemozoin Inhibitors Using Physicochemical Properties. Antimicrob Agents Chemother 2017; 61:AAC.01607-16. [PMID: 27919903 DOI: 10.1128/aac.01607-16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 10/14/2016] [Indexed: 12/13/2022] Open
Abstract
It is essential to continue the search for novel antimalarial drugs due to the current spread of resistance against artemisinin by Plasmodium falciparum parasites. In this study, we developed in silico models to predict hemozoin inhibitors as a potential first-step screening for novel antimalarials. An in vitro colorimetric high-throughput screening assay of hemozoin formation was used to identify hemozoin inhibitors from 9,600 structurally diverse compounds. The physicochemical properties of positive hits and randomly selected compounds were extracted from the ChemSpider database; they were used for developing prediction models to predict hemozoin inhibitors using two different approaches, i.e., traditional multivariate logistic regression and Bayesian model averaging. Our results showed that a total of 224 positive-hit compounds exhibited the ability to inhibit hemozoin formation, with 50% inhibitory concentrations (IC50s) ranging from 3.1 μM to 199.5 μM. The best model according to traditional multivariate logistic regression included the three variables octanol-water partition coefficient, number of hydrogen bond donors, and number of atoms of hydrogen, while the best model according to Bayesian model averaging included the three variables octanol-water partition coefficient, number of hydrogen bond donors, and index of refraction. Both models had a good discriminatory power, with area under the curve values of 0.736 and 0.781 for the traditional multivariate model and Bayesian model averaging, respectively. In conclusion, the prediction models can be a new, useful, and cost-effective approach for the first screen of hemozoin inhibition-based antimalarial drug discovery.
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Sandlin R, Fong KY, Stiebler R, Gulka C, Nesbitt JE, Oliveira MP, Oliveira MF, Wright DW. Detergent-Mediated Formation of β-Hematin: Heme Crystallization Promoted by Detergents Implicates Nanostructure Formation for Use as a Biological Mimic. CRYSTAL GROWTH & DESIGN 2016; 16:2542-2551. [PMID: 27175104 PMCID: PMC4860678 DOI: 10.1021/acs.cgd.5b01580] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 03/07/2016] [Indexed: 06/05/2023]
Abstract
Hemozoin is a unique biomineral that results from the sequestration of toxic free heme liberated as a consequence of hemoglobin degradation in the malaria parasite. Synthetic neutral lipid droplets (SNLDs) and phospholipids were previously shown to support the rapid formation of β-hematin, abiological hemozoin, under physiologically relevant pH and temperature, though the mechanism by which heme crystallization occurs remains unclear. Detergents are particularly interesting as a template because they are amphiphilic molecules that spontaneously organize into nanostructures and have been previously shown to mediate β-hematin formation. Here, 11 detergents were investigated to elucidate the physicochemical properties that best recapitulate crystal formation in the parasite. A strong correlation between the detergent's molecular structure and the corresponding kinetics of β-hematin formation was observed, where higher molecular weight polar chains promoted faster reactions. The larger hydrophilic chains correlated to the detergent's ability to rapidly sequester heme into the lipophilic core, allowing for crystal nucleation to occur. The data presented here suggest that detergent nanostructures promote β-hematin formation in a similar manner to SNLDs and phospholipids. Through understanding mediator properties that promote optimal crystal formation, we are able to establish an in vitro assay to probe this drug target pathway.
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Affiliation(s)
- Rebecca
D. Sandlin
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee, United States
| | - Kim Y. Fong
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee, United States
| | - Renata Stiebler
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee, United States
- Laboratório de
Biologia Celular, Instituto Oswaldo Cruz, Fundação Oswaldo
Cruz, Rio de Janeiro, Brazil
| | - Christopher
P. Gulka
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee, United States
| | - Jenny E. Nesbitt
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee, United States
| | - Matheus P. Oliveira
- Laboratório
de Bioquímica de Resposta ao Estresse, Programa de Biologia
Molecular e Biotecnologia, Instituto de Bioquímica Médica,
Leopoldo de Meis, Universidade Federal do
Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Marcus F. Oliveira
- Laboratório
de Bioquímica de Resposta ao Estresse, Programa de Biologia
Molecular e Biotecnologia, Instituto de Bioquímica Médica,
Leopoldo de Meis, Universidade Federal do
Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - David W. Wright
- Department
of Chemistry, Vanderbilt University, Nashville, Tennessee, United States
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Vekilov PG, Rimer JD, Olafson KN, Ketchum MA. Lipid or aqueous medium for hematin crystallization? CrystEngComm 2015. [DOI: 10.1039/c5ce01178g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hematin crystallization, the primary heme detoxification mechanism of malaria parasites infecting human erythrocytes, most likely requires the participation of lipid structures.
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Affiliation(s)
- Peter G. Vekilov
- Department of Chemical and Biomolecular Engineering
- University of Houston
- Houston, USA
- Department of Chemistry
- University of Houston
| | - Jeffrey D. Rimer
- Department of Chemical and Biomolecular Engineering
- University of Houston
- Houston, USA
| | - Katy N. Olafson
- Department of Chemical and Biomolecular Engineering
- University of Houston
- Houston, USA
| | - Megan A. Ketchum
- Department of Chemical and Biomolecular Engineering
- University of Houston
- Houston, USA
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Stiebler R, Majerowicz D, Knudsen J, Gondim KC, Wright DW, Egan TJ, Oliveira MF. Unsaturated glycerophospholipids mediate heme crystallization: biological implications for hemozoin formation in the kissing bug Rhodnius prolixus. PLoS One 2014; 9:e88976. [PMID: 24586467 PMCID: PMC3935856 DOI: 10.1371/journal.pone.0088976] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Accepted: 01/17/2014] [Indexed: 11/19/2022] Open
Abstract
Hemozoin (Hz) is a heme crystal produced by some blood-feeding organisms, as an efficient way to detoxify heme derived from hemoglobin digestion. In the triatomine insect Rhodnius prolixus, Hz is essentially produced by midgut extracellular phospholipid membranes known as perimicrovillar membranes (PMVM). Here, we investigated the role of commercial glycerophospholipids containing serine, choline and ethanolamine as headgroups and R. prolixus midgut lipids (RML) in heme crystallization. All commercial unsaturated forms of phospholipids, as well as RML, mediated fast and efficient β-hematin formation by means of two kinetically distinct mechanisms: an early and fast component, followed by a late and slow one. The fastest reactions observed were induced by unsaturated forms of phosphatidylethanolamine (uPE) and phosphatidylcholine (uPC), with half-lives of 0.04 and 0.7 minutes, respectively. β-hematin crystal morphologies were strikingly distinct among groups, with uPE producing homogeneous regular brick-shaped crystals. Interestingly, uPC-mediated reactions resulted in two morphologically distinct crystal populations: one less representative group of regular crystals, resembling those induced by uPE, and the other largely represented by crystals with numerous sharp edges and tapered ends. Heme crystallization reactions induced by RML were efficient, with a heme to β-hematin conversion rate higher than 70%, but clearly slower (t1/2 of 9.9-17.7 minutes) than those induced by uPC and uPE. Interestingly, crystals produced by RML were homogeneous in shape and quite similar to those mediated by uPE. Thus, β-hematin formation can be rapidly and efficiently induced by unsaturated glycerophospholipids, particularly uPE and uPC, and may play a role on biological heme crystallization in R. prolixus midgut.
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Affiliation(s)
- Renata Stiebler
- Laboratório de Bioquímica de Resposta ao Estresse, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, RJ, Brazil
- Laboratório de Inflamação e Metabolismo, Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - David Majerowicz
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, RJ, Brazil
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
- Departamento de Biotecnologia Farmacêutica, Faculdade de Farmácia,Universidade Federal do Rio de Janeiro, RJ, Brazil
| | - Jens Knudsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Katia C. Gondim
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, RJ, Brazil
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Rio de Janeiro, RJ, Brazil
| | - David W. Wright
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Timothy J. Egan
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch, South Africa
| | - Marcus F. Oliveira
- Laboratório de Bioquímica de Resposta ao Estresse, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, RJ, Brazil
- Laboratório de Inflamação e Metabolismo, Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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10
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Phospholipid membrane-mediated hemozoin formation: the effects of physical properties and evidence of membrane surrounding hemozoin. PLoS One 2013; 8:e70025. [PMID: 23894579 PMCID: PMC3720957 DOI: 10.1371/journal.pone.0070025] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Accepted: 06/20/2013] [Indexed: 11/19/2022] Open
Abstract
Phospholipid membranes are thought to be one of the main inducers of hemozoin formation in Plasmodia and other blood-feeding parasites. The “membrane surrounding hemozoin” has been observed in infected cells but has not been observed in in vitro experiments. This study focused on observing the association of phospholipid membranes and synthetic β-hematin, which is chemically identical to hemozoin, and on a further exploration into the mechanism of phospholipid membrane-induced β-hematin formation. Our results showed that β-hematin formation was induced by phospholipids in the fluid phase but not in the gel phase. The ability of phospholipids to induce β-hematin formation was inversely correlated with gel-to-liquid phase transition temperatures, suggesting an essential insertion of heme into the hydrocarbon chains of the phospholipid membrane to form β-hematin. For this study, a cryogenic transmission electron microscope was used to achieve the first direct observation of the formation of a monolayer of phospholipid membrane surrounding β-hematin.
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11
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Orjih AU, Mathew TC, Cherian PT. Erythrocyte membranes convert monomeric ferriprotoporphyrin IX to β-hematin in acidic environment at malarial fever temperature. Exp Biol Med (Maywood) 2012; 237:884-93. [PMID: 22890028 DOI: 10.1258/ebm.2012.012013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hemozoin production makes it possible for intraerythrocytic malaria parasites to digest massive quantities of hemoglobin but still avoid potential ferriprotoporphyrin IX (FP) toxicity, which they cannot decompose further. Some antimalarial drugs, such as chloroquine, work by inhibiting this production, forcing the parasite to starve to death. As part of the efforts to identify possible biological mechanisms of FP polymerization, we have used normal human erythrocyte membranes as a model, to promote β-hematin (β-h) synthesis. Hemin in 35% aqueous dimethyl sulfoxide (DMSO) was reacted with isolated erythrocyte membranes and incubated overnight in sodium acetate buffer, pH 4.8, at 41°C. Infrared spectroscopy and electron microscopy showed that β-h was produced. Hemin in 10% was less effective as the substrate than when it was in 35% DMSO. A high malarial temperature seemed to be necessary, because FP polymerization was less at 37°C than at 41°C. Production was partially inhibited by chloroquine. These observations are of interest because other investigators have reported that membrane lipids mediated FP polymerization, but whole membranes were ineffective. On the other hand, our hypothesis is that the transport vesicles (TV) in malaria parasites could provide the receptor for FP and the lipids that promote hemozoin formation. Erythrocyte membranes may not be directly involved, but Plasmodium species transport hemoglobin in membrane-bound TV into food vacuoles, where hemoglobin catabolism is completed and hemozoin crystals are stored.
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Affiliation(s)
- Augustine U Orjih
- Department of Medical Laboratory Sciences, Kuwait University, Kuwait, Arabian Gulf.
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Nhien NTT, Huy NT, Uyen DT, Deharo E, Hoa PTL, Hirayama K, Harada S, Kamei K. Effect of Inducers, Incubation Time and Heme Concentration on IC(50) Value Variation in Anti-heme Crystallization Assay. Trop Med Health 2012; 39:119-26. [PMID: 22438701 PMCID: PMC3289280 DOI: 10.2149/tmh.2011-29] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 10/24/2011] [Indexed: 11/11/2022] Open
Abstract
Heme detoxification through crystallization into hemozoin has been suggested as a good target for the development of screening assays for new antimalarials. However, comparisons among the data obtained from different experiments are difficult, and the IC50 values (the concentrations of drug that are required to inhibit 50% of hemozoin formation) for the same drug vary widely. We studied the effects of changes in heme concentration (precursor of β-hematin), incubation time and three inducers (SDS, Tween 20 and linoleic acid) on the IC50 of some antimalarials (chloroquine, quinine, amodiaquine, and clotrimazole). The results showed that increasing both inducer concentration and incubation time raised the IC50 of selected antimalarials. Any change in those factors caused the IC50 value to vary. Standardization of assay conditions is, therefore, necessary to increase reproducibility and reduce discrepancies in assay performance. Considering all of the variables, the best choice of inducers is in the order of SDS > Tween 20 > linoleic acid.
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Affiliation(s)
- Nguyen Thanh Thuy Nhien
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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Stiebler R, Soares JBRC, Timm BL, Silva JR, Mury FB, Dansa-Petretski M, Oliveira MF. On the mechanisms involved in biological heme crystallization. J Bioenerg Biomembr 2011; 43:93-9. [PMID: 21301942 DOI: 10.1007/s10863-011-9335-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Blood-feeding organisms digest hemoglobin, releasing large quantities of heme inside their digestive tracts. Free heme is very toxic, and these organisms have evolved several mechanisms to protect against its deleterious effects. One of these adaptations is the crystallization of heme into the dark-brown pigment hemozoin (Hz). Here we review the process of Hz formation, focusing on organisms other than Plasmodium that have contributed to a better understanding of heme crystallization. Hemozoin has been found in several distinct classes of organisms including protozoa, helminths and insects and Hz formation is the predominant form of heme detoxification. The available evidence indicates that amphiphilic structures such as phospholipid membranes and lipid droplets accompanied by specific proteins play a major role in heme crystallization. Because this process is specific to a number of blood-feeding organisms and absent in their hosts, Hz formation is an attractive target for the development of novel drugs to control illnesses associated with these hematophagous organisms.
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Affiliation(s)
- Renata Stiebler
- Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
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Increase on the initial soluble heme levels in acidic conditions is an important mechanism for spontaneous heme crystallization in vitro. PLoS One 2010; 5:e12694. [PMID: 20856937 PMCID: PMC2938344 DOI: 10.1371/journal.pone.0012694] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 08/06/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Hemozoin (Hz) is a heme crystal that represents a vital pathway for heme disposal in several blood-feeding organisms. Recent evidence demonstrated that β-hematin (βH) (the synthetic counterpart of Hz) formation occurs under physiological conditions near synthetic or biological hydrophilic-hydrophobic interfaces. This seems to require a heme dimer acting as a precursor of Hz crystals that would be formed spontaneously in the absence of the competing water molecules bound to the heme iron. Here, we aimed to investigate the role of medium polarity on spontaneous βH formation in vitro. METHODOLOGY/PRINCIPAL FINDINGS We assessed the effect of water content on spontaneous βH formation by using the aprotic solvent dimethylsulfoxide (DMSO) and a series of polyethyleneglycols (PEGs). We observed that both DMSO and PEGs (3.350, 6.000, 8.000, and 22.000) increased the levels of soluble heme under acidic conditions. These compounds were able to stimulate the production of βH crystals in the absence of any biological sample. Interestingly, the effects of DMSO and PEGs on βH formation were positively correlated with their capacity to promote previous heme solubilization in acidic conditions. Curiously, a short chain polyethyleneglycol (PEG 300) caused a significant reduction in both soluble heme levels and βH formation. Finally, both heme solubilization and βH formation strongly correlated with reduced medium water activity provided by increased DMSO concentrations. CONCLUSIONS The data presented here support the notion that reduction of the water activity is an important mechanism to support spontaneous heme crystallization, which depends on the previous increase of soluble heme levels.
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Hoang AN, Ncokazi KK, de Villiers KA, Wright DW, Egan TJ. Crystallization of synthetic haemozoin (beta-haematin) nucleated at the surface of lipid particles. Dalton Trans 2009; 39:1235-44. [PMID: 20104349 DOI: 10.1039/b914359a] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mechanism of formation of haemozoin, a detoxification by-product of several blood-feeding organisms including malaria parasites, has been a subject of debate; however, recent studies suggest that neutral lipids may serve as a catalyst. In this study, a model system consisting of an emulsion of neutral lipid particles was employed to investigate the formation of beta-haematin, the synthetic counterpart of haemozoin, at the lipid-water interface. A solution of monoglyceride, either monostearoylglycerol (MSG) or monopalmitoylglycerol (MPG), dissolved in acetone and methanol was introduced to an aqueous surface. Fluorescence, confocal and transmission electron microscopic (TEM) imaging and dynamic light scattering analysis of samples obtained from beneath the surface confirmed the presence of homogeneous lipid particles existing in two major populations: one in the low micrometre size range and the other in the hundred nanometre range. The introduction of haem (Fe(iii)PPIX) to this lipid particle system under biomimetic conditions (37 degrees C, pH 4.8) produced beta-haematin with apparent first-order kinetics and an average half life of 0.5 min. TEM of monoglycerides (MSG or MPG) extruded through a 200 nm filter with haem produced beta-haematin crystals aligned and parallel to the lipid-water interface. These TEM data, together with a model system replacing the lipid with an aqueous organic solvent interface using either methyl laurate or docosane demonstrated that the OH and C[double bond, length as m-dash]O groups are apparently necessary for efficient nucleation. This suggests that beta-haematin crystallizes via epitaxial nucleation at the lipid-water interface through interaction of Fe(iii)PPIX with the polar head group. Once nucleated, the crystal grows parallel to the interface until growth is terminated by the curvature of the lipid particle. The hydrophobic nature of the mature crystal favours an interior transport resulting in crystals aligned parallel to the lipid-water interface and each other, strikingly similar to that seen in malaria parasites.
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Affiliation(s)
- Anh N Hoang
- Department of Chemistry, Vanderbilt University, Station B351822, Nashville, TN 37235, USA
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Egan TJ. Recent advances in understanding the mechanism of hemozoin (malaria pigment) formation. J Inorg Biochem 2008; 102:1288-99. [DOI: 10.1016/j.jinorgbio.2007.12.004] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Revised: 10/19/2007] [Accepted: 10/31/2007] [Indexed: 11/15/2022]
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Uyen DT, Huy NT, Trang DTX, Nhien NTT, Oida T, Hirayama K, Harada S, Kamei K. Effects of Amino Acids on Malarial Heme Crystallization. Biol Pharm Bull 2008; 31:1483-8. [DOI: 10.1248/bpb.31.1483] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Dinh Thanh Uyen
- Department of Applied Biology, Kyoto Institute of Technology
| | - Nguyen Tien Huy
- Department of Applied Biology, Kyoto Institute of Technology
- Department of Immunogenetics, Institute of Tropical Medicine (NEKKEN), Nagasaki University
| | | | | | - Tatsuo Oida
- Department of Materials and Science, Kyoto Institute of Technology
| | - Kenji Hirayama
- Department of Immunogenetics, Institute of Tropical Medicine (NEKKEN), Nagasaki University
| | | | - Kaeko Kamei
- Department of Applied Biology, Kyoto Institute of Technology
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Hemozoin: oil versus water. Parasitol Int 2007; 57:89-96. [PMID: 18373972 DOI: 10.1016/j.parint.2007.09.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Revised: 09/26/2007] [Accepted: 09/28/2007] [Indexed: 11/23/2022]
Abstract
Because the quinolines inhibit heme crystallization within the malaria parasite much work has focused on mechanism of formation and inhibition of hemozoin. Here we review the recent evidence for heme crystallization within lipids in diverse parasites and the new implications of a lipid site of crystallization for drug targeting. Within leukocytes hemozoin can generate toxic radical lipid metabolites, which may alter immune function or reduce deformability of uninfected erythrocytes.
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Huy NT, Mizunuma K, Kaur K, Nhien NTT, Jain M, Uyen DT, Harada S, Jain R, Kamei K. 2-tert-butyl-8-quinolinamines exhibit potent blood schizontocidal antimalarial activity via inhibition of heme crystallization. Antimicrob Agents Chemother 2007; 51:2842-7. [PMID: 17562796 PMCID: PMC1932521 DOI: 10.1128/aac.00288-07] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have recently reported that the attachment of a bulky metabolically stable tert-butyl group at the C-2 position of a quinoline ring in primaquine results in a tremendous improvement in the blood schizontocidal antimalarial activity of 8-quinolinamine. Because free heme released from hemoglobin catabolism in a malarial parasite is highly toxic, the parasite protects itself mainly by crystallization of heme into insoluble nontoxic hemozoin. We now demonstrate the ability of 2-tert-butylprimaquine to inhibit in vitro beta-hematin formation, to form a complex with heme with a stoichiometry of 1:1, and to enhance heme-induced hemolysis. The results described herein indicate that a major improvement in the blood-schizontocidal antimalarial activity of 2-tert-butylprimaquine might be due to a disturbance of heme catabolism pathway in the malarial parasite.
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Affiliation(s)
- Nguyen Tien Huy
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Kyoto, Japan
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