151
|
Shio MT, Kassa FA, Bellemare MJ, Olivier M. Innate inflammatory response to the malarial pigment hemozoin. Microbes Infect 2010; 12:889-99. [PMID: 20637890 DOI: 10.1016/j.micinf.2010.07.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 07/01/2010] [Accepted: 07/02/2010] [Indexed: 11/19/2022]
Abstract
Malaria is an infectious disease caused by parasites of the genus Plasmodium. This intraerythrocytic protozoan produces hemozoin (HZ), an insoluble crystalline metabolite resulting from the heme detoxification mechanism. This review will focus on HZ biosynthesis and synthetic preparation, but in particular on its effect on host's innate inflammatory responses.
Collapse
Affiliation(s)
- Marina T Shio
- Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
| | | | | | | |
Collapse
|
152
|
Abstract
This chapter summarizes recent developments in the design, synthesis, and structure–activity relationship studies of organometallic antimalarials. It begins with a general introduction to malaria and the biology of the parasite Plasmodium falciparum, with a focus on the heme detoxification system. Then, a number of metal complexes from the literature are reported for their antiplasmodial activity. The second half of the chapter deals with the serendipitous discovery of ferroquine, its mechanism(s) of action, and the failure to induce a resistance. Last, but not least, we suggest that the bioorganometallic approach offers the potential for the design of novel therapeutic agents.
Collapse
|
153
|
Baker J, Ho MF, Pelecanos A, Gatton M, Chen N, Abdullah S, Albertini A, Ariey F, Barnwell J, Bell D, Cunningham J, Djalle D, Echeverry DF, Gamboa D, Hii J, Kyaw MP, Luchavez J, Membi C, Menard D, Murillo C, Nhem S, Ogutu B, Onyor P, Oyibo W, Wang SQ, McCarthy J, Cheng Q. Global sequence variation in the histidine-rich proteins 2 and 3 of Plasmodium falciparum: implications for the performance of malaria rapid diagnostic tests. Malar J 2010; 9:129. [PMID: 20470441 PMCID: PMC2893195 DOI: 10.1186/1475-2875-9-129] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Accepted: 05/17/2010] [Indexed: 11/20/2022] Open
Abstract
Background Accurate diagnosis is essential for prompt and appropriate treatment of malaria. While rapid diagnostic tests (RDTs) offer great potential to improve malaria diagnosis, the sensitivity of RDTs has been reported to be highly variable. One possible factor contributing to variable test performance is the diversity of parasite antigens. This is of particular concern for Plasmodium falciparum histidine-rich protein 2 (PfHRP2)-detecting RDTs since PfHRP2 has been reported to be highly variable in isolates of the Asia-Pacific region. Methods The pfhrp2 exon 2 fragment from 458 isolates of P. falciparum collected from 38 countries was amplified and sequenced. For a subset of 80 isolates, the exon 2 fragment of histidine-rich protein 3 (pfhrp3) was also amplified and sequenced. DNA sequence and statistical analysis of the variation observed in these genes was conducted. The potential impact of the pfhrp2 variation on RDT detection rates was examined by analysing the relationship between sequence characteristics of this gene and the results of the WHO product testing of malaria RDTs: Round 1 (2008), for 34 PfHRP2-detecting RDTs. Results Sequence analysis revealed extensive variations in the number and arrangement of various repeats encoded by the genes in parasite populations world-wide. However, no statistically robust correlation between gene structure and RDT detection rate for P. falciparum parasites at 200 parasites per microlitre was identified. Conclusions The results suggest that despite extreme sequence variation, diversity of PfHRP2 does not appear to be a major cause of RDT sensitivity variation.
Collapse
Affiliation(s)
- Joanne Baker
- Department of Drug Resistance and Diagnostics, Australian Army Malaria Institute, Brisbane, Australia.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
154
|
Lim L, McFadden GI. The evolution, metabolism and functions of the apicoplast. Philos Trans R Soc Lond B Biol Sci 2010; 365:749-63. [PMID: 20124342 PMCID: PMC2817234 DOI: 10.1098/rstb.2009.0273] [Citation(s) in RCA: 197] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The malaria parasite, Plasmodium falciparum, harbours a relict plastid known as the ‘apicoplast’. The discovery of the apicoplast ushered in an exciting new prospect for drug development against the parasite. The eubacterial ancestry of the organelle offers a wealth of opportunities for the development of therapeutic interventions. Morphological, biochemical and bioinformatic studies of the apicoplast have further reinforced its ‘plant-like’ characteristics and potential as a drug target. However, we are still not sure why the apicoplast is essential for the parasite's survival. This review explores the origins and metabolic functions of the apicoplast. In an attempt to decipher the role of the organelle within the parasite we also take a closer look at the transporters decorating the plastid to better understand the metabolic exchanges between the apicoplast and the rest of the parasite cell.
Collapse
Affiliation(s)
- Liting Lim
- School of Botany, University of Melbourne, Parkville, Victoria 3010, Australia
| | | |
Collapse
|
155
|
Plasmepsin V licenses Plasmodium proteins for export into the host erythrocyte. Nature 2010; 463:632-6. [PMID: 20130644 PMCID: PMC2826791 DOI: 10.1038/nature08726] [Citation(s) in RCA: 221] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 12/07/2009] [Indexed: 12/03/2022]
Abstract
During their intraerythrocytic development, malaria parasites export hundreds of proteins to remodel their host cell. Nutrient acquisition, cytoadherence and antigenic variation are among the key virulence functions effected by this erythrocyte takeover. Proteins destined for export are synthesized in the endoplasmic reticulum (ER) and cleaved at a conserved (PEXEL) motif, which allows translocation into the host cell via an ATP-driven translocon called the PTEX complex. We report that plasmepsin V, an ER aspartic protease with distant homology to the mammalian processing enzyme BACE, recognizes the PEXEL motif and cleaves it at the correct site. This enzyme is essential for parasite viability and ER residence is essential for its function. We propose that plasmepsin V is the PEXEL protease and is an attractive enzyme for antimalarial drug development.
Collapse
|
156
|
Stiebler R, Timm BL, Oliveira PL, Hearne GR, Egan TJ, Oliveira MF. On the physico-chemical and physiological requirements of hemozoin formation promoted by perimicrovillar membranes in Rhodnius prolixus midgut. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2010; 40:284-292. [PMID: 20060043 DOI: 10.1016/j.ibmb.2009.12.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Revised: 12/21/2009] [Accepted: 12/22/2009] [Indexed: 05/28/2023]
Abstract
Triatomine insects are obligatory blood-feeders that detoxify most of the hemoglobin-derived heme through its crystallization into hemozoin (Hz). Previous evidence demonstrates the key role of midgut perimicrovillar membranes (PMVM) on heme crystallization in triatomines. Here, we investigated some of the physico-chemical and physiological aspects of heme crystallization induced by Rhodnius prolixus PMVM. Hz formation in vitro proceeded optimally at pH 4.8 and 28 degrees C, apparently involving three kinetically distinct mechanisms along this process. Furthermore, the insect feeding status and age affected PMVM-induced heme crystallization whereas pharmacological blockage of PMVM formation by azadirachtin, reduced hemoglobin digestion and Hz formation in vivo. Mössbauer spectrometry analyses of R. prolixus midgut showed that Hz represents the only measurable iron species found four days after a blood meal. Autocatalytic heme crystallization to Hz is revealed to be an inefficient process and this conversion is further reduced as the Hz concentration increases. Also, PMVM-derived lipids were able to induce rapid Hz formation, regardless of the diet composition. These results indicate that PMVM-driven Hz formation in R. prolixus midgut occurs at physiologically relevant physico-chemical conditions and that lipids derived from this structure play an important role in heme crystallization.
Collapse
Affiliation(s)
- Renata Stiebler
- Laboratório de Bioquímica Redox, Programa de Biologia Molecular e Biotecnologia, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | | | | | | | | | | |
Collapse
|
157
|
Ghanchi NK, Beg MA, Hussain R. Estimation of parasite load using Rapid diagnostic test ICT Now Malaria P.f/P.v in Plasmodium falciparum malaria. ACTA ACUST UNITED AC 2010; 41:597-601. [PMID: 19479634 DOI: 10.1080/00365540903022832] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Rapid tests such as ICT Malaria are an effective field tool in determining the presence of malarial parasites but do not provide an estimate of parasite load. We have evaluated the utility of ICT for providing semi-quantitative estimates of parasite load. Circulating parasite load in the blood of patients with malaria (n =54), were compared with the circulating HRP2 protein levels. Blood was serially diluted and analysed by a rapid diagnostic test (ICT(R) Now P.f/P.v) for assessment of endpoint PfHRP2 antigen titres. Significant correlation was observed between parasite load and PfHRP2 antigen titres (Spearman rank; rho = 0.821; p<0.001) with plasma dilutions > 1:16 corresponding to a parasite load of 0.1% parasitaemia. Variability in haematological parameters had no effect on the antibody titres obtained with the ICT test. Rapid semi-quantitative assessment of parasite load in conjunction with the Plasmodium speciation may provide a useful bedside and field aid in the diagnosis of malaria.
Collapse
Affiliation(s)
- Najia K Ghanchi
- Department of Pathology and Microbiology, Aga Khan University, Karachi, Pakistan
| | | | | |
Collapse
|
158
|
Bae DR, Han WS, Lim JM, Kang S, Lee JY, Kang D, Jung JH. Lysine-functionalized silver nanoparticles for visual detection and separation of histidine and histidine-tagged proteins. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:2181-2185. [PMID: 19715339 DOI: 10.1021/la9026865] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A new chromogenic chemosensor based on lysine-functionalized silver nanoparticles 1 was prepared and characterized by transmission electron microscopy (TEM), Fourier transform Raman, and ultraviolet-visible (UV-vis) spectroscopy. The color changes of nanoparticles 1 in the absence and the presence of metal ion were observed upon addition of various amino acids and proteins in aqueous solution. Among the various amino acids, the sensor 1 in the absence of metal ion shows a novel colorimetric sensor with capability to probe histidine and histidine-tagged proteins. On the other hand, the color changes of 1 in the presence of metal ions such as KCl or NiCl(2) did not occur with any amino acids. Therefore, the sensor 1 in the absence of metal ion responds selectively to histidine, a response which can be attributed to its aggregation induced by histidine with high numbers of electrostatic interactions. This highly selective sensor 1 allows a rapid quantitative assay of histidine to concentrations as low as 5.0 microM, providing a new tool for the direct measurement of histidine and histidine-tagged proteins in vitro system. Furthermore, we examined the effect of pH on absorbance (A(520)) of 1 in the presence of histidine (pH 4-12). The absorbance under basic conditions was higher than that under acidic or neutral conditions, in accord with the stronger aggregation of 1 with histidine by electrostatic interaction between the carboxylate anion of 1 and ammonium protons of histidine under basic conditions.
Collapse
Affiliation(s)
- Doo Ri Bae
- Department of Chemistry and Research Institute of Natural Sciences and Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea
| | | | | | | | | | | | | |
Collapse
|
159
|
Zhao Q, Li F, Huang C. Phosphorescent chemosensors based on heavy-metal complexes. Chem Soc Rev 2010; 39:3007-30. [DOI: 10.1039/b915340c] [Citation(s) in RCA: 1038] [Impact Index Per Article: 74.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
160
|
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.
Collapse
Affiliation(s)
- Anh N Hoang
- Department of Chemistry, Vanderbilt University, Station B351822, Nashville, TN 37235, USA
| | | | | | | | | |
Collapse
|
161
|
Alpha-glucosidase promotes hemozoin formation in a blood-sucking bug: an evolutionary history. PLoS One 2009; 4:e6966. [PMID: 19742319 PMCID: PMC2734994 DOI: 10.1371/journal.pone.0006966] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 07/17/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Hematophagous insects digest large amounts of host hemoglobin and release heme inside their guts. In Rhodnius prolixus, hemoglobin-derived heme is detoxified by biomineralization, forming hemozoin (Hz). Recently, the involvement of the R. prolixus perimicrovillar membranes in Hz formation was demonstrated. METHODOLOGY/PRINCIPAL FINDINGS Hz formation activity of an alpha-glucosidase was investigated. Hz formation was inhibited by specific alpha-glucosidase inhibitors. Moreover, Hz formation was sensitive to inhibition by Diethypyrocarbonate, suggesting a critical role of histidine residues in enzyme activity. Additionally, a polyclonal antibody raised against a phytophagous insect alpha-glucosidase was able to inhibit Hz formation. The alpha-glucosidase inhibitors have had no effects when used 10 h after the start of reaction, suggesting that alpha-glucosidase should act in the nucleation step of Hz formation. Hz formation was seen to be dependent on the substrate-binding site of enzyme, in a way that maltose, an enzyme substrate, blocks such activity. dsRNA, constructed using the sequence of alpha-glucosidase gene, was injected into R. prolixus females' hemocoel. Gene silencing was accomplished by reduction of both alpha-glucosidase and Hz formation activities. Insects were fed on plasma or hemin-enriched plasma and gene expression and activity of alpha-glucosidase were higher in the plasma plus hemin-fed insects. The deduced amino acid sequence of alpha-glucosidase shows a high similarity to the insect alpha-glucosidases, with critical histidine and aspartic residues conserved among the enzymes. CONCLUSIONS/SIGNIFICANCE Herein the Hz formation is shown to be associated to an alpha-glucosidase, the biochemical marker from Hemipteran perimicrovillar membranes. Usually, these enzymes catalyze the hydrolysis of glycosidic bond. The results strongly suggest that alpha-glucosidase is responsible for Hz nucleation in the R. prolixus midgut, indicating that the plasticity of this enzyme may play an important role in conferring fitness to hemipteran hematophagy, for instance.
Collapse
|
162
|
Sauvage V, Aubert D, Escotte-Binet S, Villena I. The role of ATP-binding cassette (ABC) proteins in protozoan parasites. Mol Biochem Parasitol 2009; 167:81-94. [PMID: 19464325 DOI: 10.1016/j.molbiopara.2009.05.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Revised: 05/11/2009] [Accepted: 05/12/2009] [Indexed: 10/20/2022]
Abstract
The ATP-binding cassette (ABC) superfamily is one of the largest protein families with representatives in all kingdoms of life. Members of this superfamily are involved in a wide variety of transport processes with substrates ranging from small ions to relatively large polypeptides and polysaccharides, but also in cellular processes such as DNA repair, translation or regulation of gene expression. For many years, the role of ABC proteins was mainly investigated for their implication in drug resistance. However, recent studies focused rather on their physiological functions for the parasite. In this review, we present an overview of ABC proteins in major protozoan parasites including Leishmania, Trypanosoma, Plasmodium, Toxoplasma, Cryptosporidium and Entamoeba species. We will also discuss the role of characterized ABC transporters in the biology of the parasite and in drug resistance.
Collapse
Affiliation(s)
- Virginie Sauvage
- Laboratoire de Parasitologie-Mycologie, EA 3800, IFR 53, UFR Médecine, Université de Reims Champagne-Ardenne, 51 rue Cognacq-Jay, 51095 Reims Cedex, France
| | | | | | | |
Collapse
|
163
|
Maier AG, Cooke BM, Cowman AF, Tilley L. Malaria parasite proteins that remodel the host erythrocyte. Nat Rev Microbiol 2009; 7:341-54. [PMID: 19369950 DOI: 10.1038/nrmicro2110] [Citation(s) in RCA: 289] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Exported proteins of the malaria parasite Plasmodium falciparum interact with proteins of the erythrocyte membrane and induce substantial changes in the morphology, physiology and function of the host cell. These changes underlie the pathology that is responsible for the deaths of 1-2 million children every year due to malaria infections. The advent of molecular transfection technology, including the ability to generate deletion mutants and to introduce fluorescent reporter proteins that track the locations and dynamics of parasite proteins, has increased our understanding of the processes and machinery for export of proteins in P. falciparum-infected erythrocytes and has provided us with insights into the functions of the parasite protein exportome. We review these developments, focusing on parasite proteins that interact with the erythrocyte membrane skeleton or that promote delivery of the major virulence protein, PfEMP1, to the erythrocyte membrane.
Collapse
Affiliation(s)
- Alexander G Maier
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Melbourne, Victoria, Australia
| | | | | | | |
Collapse
|
164
|
A Maurer’s cleft-associated Plasmodium falciparum membrane-associated histidine-rich protein peptide specifically interacts with the erythrocyte membrane. Biochem Biophys Res Commun 2009; 380:122-6. [DOI: 10.1016/j.bbrc.2009.01.050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Accepted: 01/13/2009] [Indexed: 11/18/2022]
|
165
|
Antimalarial drugs and heme in detergent micelles: An NMR study. J Inorg Biochem 2009; 103:745-8. [PMID: 19223262 DOI: 10.1016/j.jinorgbio.2009.01.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 01/14/2009] [Accepted: 01/15/2009] [Indexed: 11/23/2022]
Abstract
Proton nuclear magnetic resonance relaxation times were measured for the protons of micelles formed by the detergents sodium dodecyl sulfate, dodecyltrimethyl ammonium bromide, and polyethylene glycol sorbitan monolaureate in the presence of ferriprotoporphyrin IX and the antimalarial drugs chloroquine, 7-chloro-4-quinolyl 4-N,N-diethylaminobutyl sulfide, and primaquine. Diffusion coefficients were extracted from pulsed gradient NMR experiments to evaluate the degree of association of these drugs with the detergent micelles. Results indicate that at low or neutral pH when the quinolyl N is protonated, chloroquine does not associate with neutral or cationic detergent micelles. For this reason, chloroquine's interaction with heme perturbs the partitioning of heme between the aqueous medium and detergent micelles.
Collapse
|
166
|
Weissbuch I, Leiserowitz L. Interplay Between Malaria, Crystalline Hemozoin Formation, and Antimalarial Drug Action and Design. Chem Rev 2008; 108:4899-914. [DOI: 10.1021/cr078274t] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Isabelle Weissbuch
- Department of Materials and Interfaces, The Weizmann Institute of Science, 76100-Rehovot, Israel
| | - Leslie Leiserowitz
- Department of Materials and Interfaces, The Weizmann Institute of Science, 76100-Rehovot, Israel
| |
Collapse
|
167
|
Dluzewski AR, Ling IT, Hopkins JM, Grainger M, Margos G, Mitchell GH, Holder AA, Bannister LH. Formation of the food vacuole in Plasmodium falciparum: a potential role for the 19 kDa fragment of merozoite surface protein 1 (MSP1(19)). PLoS One 2008; 3:e3085. [PMID: 18769730 PMCID: PMC2518119 DOI: 10.1371/journal.pone.0003085] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Accepted: 07/18/2008] [Indexed: 01/11/2023] Open
Abstract
Plasmodium falciparum Merozoite Surface Protein 1 (MSP1) is synthesized during schizogony as a 195-kDa precursor that is processed into four fragments on the parasite surface. Following a second proteolytic cleavage during merozoite invasion of the red blood cell, most of the protein is shed from the surface except for the C-terminal 19-kDa fragment (MSP119), which is still attached to the merozoite via its GPI-anchor. We have examined the fate of MSP119 during the parasite's subsequent intracellular development using immunochemical analysis of metabolically labeled MSP119, fluorescence imaging, and immuno-electronmicroscopy. Our data show that MSP119 remains intact and persists to the end of the intracellular cycle. This protein is the first marker for the biogenesis of the food vacuole; it is rapidly endocytosed into small vacuoles in the ring stage, which coalesce to form the single food vacuole containing hemozoin, and persists into the discarded residual body. The food vacuole is marked by the presence of both MSP119 and the chloroquine resistance transporter (CRT) as components of the vacuolar membrane. Newly synthesized MSP1 is excluded from the vacuole. This behavior indicates that MSP119 does not simply follow a classical lysosome-like clearance pathway, instead, it may play a significant role in the biogenesis and function of the food vacuole throughout the intra-erythrocytic phase.
Collapse
Affiliation(s)
- Anton R Dluzewski
- Department of Immunobiology, Guy's, King's and St. Thomas' School of Medicine, Guy's Hospital, London, United Kingdom.
| | | | | | | | | | | | | | | |
Collapse
|
168
|
Wykes MN, Good MF. What really happens to dendritic cells during malaria? Nat Rev Microbiol 2008; 6:864-70. [DOI: 10.1038/nrmicro1988] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
169
|
Rodriguez LE, Curtidor H, Urquiza M, Cifuentes G, Reyes C, Patarroyo ME. Intimate Molecular Interactions of P. falciparum Merozoite Proteins Involved in Invasion of Red Blood Cells and Their Implications for Vaccine Design. Chem Rev 2008; 108:3656-705. [DOI: 10.1021/cr068407v] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Hernando Curtidor
- Fundación Instituto de Inmunología de Colombia, Carrera 50 No. 26-00, Bogotá, Colombia
| | - Mauricio Urquiza
- Fundación Instituto de Inmunología de Colombia, Carrera 50 No. 26-00, Bogotá, Colombia
| | - Gladys Cifuentes
- Fundación Instituto de Inmunología de Colombia, Carrera 50 No. 26-00, Bogotá, Colombia
| | - Claudia Reyes
- Fundación Instituto de Inmunología de Colombia, Carrera 50 No. 26-00, Bogotá, Colombia
| | | |
Collapse
|
170
|
Lamarque M, Tastet C, Poncet J, Demettre E, Jouin P, Vial H, Dubremetz JF. Food vacuole proteome of the malarial parasite Plasmodium falciparum. Proteomics Clin Appl 2008; 2:1361-74. [PMID: 21136929 DOI: 10.1002/prca.200700112] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Indexed: 11/08/2022]
Abstract
The Plasmodium falciparum food vacuole (FV) is a lysosome-like organelle where erythrocyte hemoglobin digestion occurs. It is a favorite target in the development of antimalarials. We have used a tandem mass spectrometry approach to investigate the proteome of an FV-enriched fraction and identified 116 proteins. The electron microscopy analysis and the Western blot data showed that the major component of the fraction was the FV and, as expected, the majority of previously known FV markers were recovered. Of particular interest, several proteins involved in vesicle-mediated trafficking were identified, which are likely to play a key role in FV biogenesis and/or FV protein trafficking. Recovery of parasite surface proteins lends support to the cytostomal pathway of hemoglobin ingestion as a FV trafficking route. We have identified 32 proteins described as hypothetical in the databases. This insight into FV protein content provides new clues towards understanding the biological function of this organelle in P. falciparum.
Collapse
Affiliation(s)
- Mauld Lamarque
- Dynamique Moléculaire des Interactions Membranaires CNRS UMR 5235, Université Montpellier II, Montpellier, France
| | | | | | | | | | | | | |
Collapse
|
171
|
Ma DL, Wong WL, Chung WH, Chan FY, So PK, Lai TS, Zhou ZY, Leung YC, Wong KY. A Highly Selective Luminescent Switch-On Probe for Histidine/Histidine-Rich Proteins and Its Application in Protein Staining. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200705319] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
172
|
Ma DL, Wong WL, Chung WH, Chan FY, So PK, Lai TS, Zhou ZY, Leung YC, Wong KY. A Highly Selective Luminescent Switch-On Probe for Histidine/Histidine-Rich Proteins and Its Application in Protein Staining. Angew Chem Int Ed Engl 2008; 47:3735-9. [DOI: 10.1002/anie.200705319] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
173
|
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]
|
174
|
Bhat A, Athar F, Van Zyl R, Chen CT, Azam A. Synthesis and Biological Evaluation of Novel 4-Substituted 1-{[4-(10,15,20-Triphenylporphyrin-5-yl)phenyl]methylidene}thiosemicarbazides as New Class of Potential Antiprotozoal Agents. Chem Biodivers 2008; 5:764-76. [DOI: 10.1002/cbdv.200890073] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
175
|
HDP-a novel heme detoxification protein from the malaria parasite. PLoS Pathog 2008; 4:e1000053. [PMID: 18437218 PMCID: PMC2291572 DOI: 10.1371/journal.ppat.1000053] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 03/28/2008] [Indexed: 11/19/2022] Open
Abstract
When malaria parasites infect host red blood cells (RBC) and proteolyze hemoglobin, a unique, albeit poorly understood parasite-specific mechanism, detoxifies released heme into hemozoin (Hz). Here, we report the identification and characterization of a novel Plasmodium Heme Detoxification Protein (HDP) that is extremely potent in converting heme into Hz. HDP is functionally conserved across Plasmodium genus and its gene locus could not be disrupted. Once expressed, the parasite utilizes a circuitous "Outbound-Inbound" trafficking route by initially secreting HDP into the cytosol of infected RBC. A subsequent endocytosis of host cytosol (and hemoglobin) delivers HDP to the food vacuole (FV), the site of Hz formation. As Hz formation is critical for survival, involvement of HDP in this process suggests that it could be a malaria drug target.
Collapse
|
176
|
Kumar S, Guha M, Choubey V, Maity P, Srivastava K, Puri SK, Bandyopadhyay U. Bilirubin inhibits Plasmodium falciparum growth through the generation of reactive oxygen species. Free Radic Biol Med 2008; 44:602-13. [PMID: 18070610 DOI: 10.1016/j.freeradbiomed.2007.10.057] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 09/28/2007] [Accepted: 10/17/2007] [Indexed: 11/25/2022]
Abstract
Free heme is very toxic because it generates highly reactive hydroxyl radicals ((.)OH) to cause oxidative damage. Detoxification of free heme by the heme oxygenase (HO) system is a very common phenomenon by which free heme is catabolized to form bilirubin as an end product. Interestingly, the malaria parasite, Plasmodium falciparum, lacks an HO system, but it forms hemozoin, mainly to detoxify free heme. Here, we report that bilirubin significantly induces oxidative stress in the parasite as evident from the increased formation of lipid peroxide, decrease in glutathione content, and increased formation of H(2)O(2) and (.)OH. Bilirubin can effectively inhibit hemozoin formation also. Furthermore, results indicate that bilirubin inhibits parasite growth and induces caspase-like protease activity, up-regulates the expression of apoptosis-related protein (Gene ID PFI0450c), and reduces the mitochondrial membrane potential. (.)OH scavengers such as mannitol, as well as the spin trap alpha-phenyl-n-tert-butylnitrone, effectively protect the parasite from bilirubin-induced oxidative stress and growth inhibition. These findings suggest that bilirubin, through the development of oxidative stress, induces P. falciparum cell death and that the malaria parasite lacks an HO system probably to protect itself from bilirubin-induced cell death as a second line of defense.
Collapse
Affiliation(s)
- Sanjay Kumar
- Drug Target Discovery and Development Division, Central Drug Research Institute, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India
| | | | | | | | | | | | | |
Collapse
|
177
|
Haemozoin formation. Mol Biochem Parasitol 2008; 157:127-36. [DOI: 10.1016/j.molbiopara.2007.11.005] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Revised: 11/05/2007] [Accepted: 11/06/2007] [Indexed: 11/18/2022]
|
178
|
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
| |
Collapse
|
179
|
Abstract
A series of [(aryl)arylsufanylmethyl]pyridines (AASMP) have been synthesized. These compounds inhibited hemozoin formation, formed complexes (K(D) = 12 to 20 muM) with free heme (ferriprotoporphyrin IX) at a pH close to the pH of the parasite food vacuole, and exhibited antimalarial activity in vitro. The inhibition of hemozoin formation may develop oxidative stress in Plasmodium falciparum due to the accumulation of free heme. Interestingly, AASMP developed oxidative stress in the parasite, as evident from the decreased level of glutathione and increased formation of lipid peroxide, H(2)O(2), and hydroxyl radical (.OH) in P. falciparum. AASMP also caused mitochondrial dysfunction by decreasing mitochondrial potential (DeltaPsim) in malaria parasite, as measured by both flow cytometry and fluorescence microscopy. Furthermore, the generation of .OH may be mainly responsible for the antimalarial effect of AASMP since .OH scavengers such as mannitol, as well as spin trap alpha-phenyl-n-tertbutylnitrone, significantly protected P. falciparum from AASMP-mediated growth inhibition. Cytotoxicity testing of the active compounds showed selective activity against malaria parasite with selectivity indices greater than 100. AASMP also exhibited profound antimalarial activity in vivo against chloroquine resistant P. yoelii. Thus, AASMP represents a novel class of antimalarial.
Collapse
|
180
|
Accardo A, Laurent SAL, Mazarguil H, Meyer M, Robert A, Meunier B. Interaction of iron(II)-heme and artemisinin with a peptide mimic of Plasmodium falciparum HRP-II. J Inorg Biochem 2007; 101:1739-47. [PMID: 17582500 DOI: 10.1016/j.jinorgbio.2007.04.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Revised: 04/25/2007] [Accepted: 04/27/2007] [Indexed: 11/26/2022]
Abstract
The interaction of heme or heme-artemisinin adducts (heme-art) with different peptides mimicking repeat sequences of the Histidine-Rich-Protein-II of Plasmodium falciparum (PfHRP-II) was investigated. The pseudo-first order rate constants of the coordination of heme or heme-art onto a histidine rich peptide, used as a mimic of PfHRP-II putative heme binding sequence, are of the same order of magnitude, namely 42 and 14 s(-1), respectively. Despite the intrinsic reactivity of the carbonyl at C10 of heme-art toward a hydroxyl function, a peptide containing a serine or threonine residue does not readily react with heme-art adducts. Therefore, a much higher affinity of heme-art compared to heme toward PfHRP-II, if so, must be induced by a specific interaction or a chemical reaction, these phenomena being both due to the tertiary structure of the parasite protein itself.
Collapse
Affiliation(s)
- Antonella Accardo
- Laboratoire de Chimie de Coordination du CNRS, 205 Route de Narbonne, 31077 Toulouse Cedex 4, France
| | | | | | | | | | | |
Collapse
|
181
|
Hänscheid T, Egan TJ, Grobusch MP. Haemozoin: from melatonin pigment to drug target, diagnostic tool, and immune modulator. THE LANCET. INFECTIOUS DISEASES 2007; 7:675-85. [PMID: 17897610 DOI: 10.1016/s1473-3099(07)70238-4] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Plasmodium spp produce a pigment (haemozoin) to detoxify the free haem that is generated by haemoglobin degradation. Haemozoin was originally thought to be an inert waste byproduct of the parasite. However, recent research has led to the recognition that haemozoin is possibly of great importance in various aspects of malaria. Haemozoin is the target of many antimalarial drugs, and the unravelling of the exact modes of action may allow the design of novel antimalarial compounds. The detection of haemozoin in erythrocytes or leucocytes facilitates the diagnosis of malaria. The number of haemozoin-containing monocytes and granulocytes has been shown to correlate well with disease severity and may hold the potential for becoming a novel, automated laboratory marker in the assessment of patients. Finally, haemozoin has a substantial effect on the immune system. Further research is needed to clarify these aspects, many of which are important in clinical practice.
Collapse
Affiliation(s)
- Thomas Hänscheid
- Institute of Molecular Medicine, Lisbon Medical College, Lisbon, Portugal
| | | | | |
Collapse
|
182
|
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.
Collapse
|
183
|
Gale GA, Kirtikara K, Pittayakhajonwut P, Sivichai S, Thebtaranonth Y, Thongpanchang C, Vichai V. In search of cyclooxygenase inhibitors, anti-Mycobacterium tuberculosis and anti-malarial drugs from Thai flora and microbes. Pharmacol Ther 2007; 115:307-51. [PMID: 17692387 DOI: 10.1016/j.pharmthera.2007.03.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2006] [Accepted: 03/12/2007] [Indexed: 02/02/2023]
Abstract
Malaria continues to be a major infectious disease of the developing world and the problem is compounded not only by the emergence of drug resistant strains but also from a lack of a vaccine. The situation for tuberculosis (TB) infection is equally problematic. Once considered a "treatable" disease for which eradication was predicted, TB has re-emerged as highly lethal, multi-drug resistant strains after the outbreak of AIDS. Worldwide, the disease causes millions of deaths annually. Similarly, treatments for chronic inflammatory diseases such as arthritis have been impeded due to the potentially lethal side effects of the new and widely prescribed non-steroidal anti-inflammatory compounds. Thais have utilized bioresources from plants and some microorganisms for medicine for thousands of years. Because of the need for new drugs to fight malaria and TB, with radically different chemical structures and mode of actions other than existing drugs, efforts have been directed towards searching for new drugs from bioresources. This is also true for anti-inflammatories. Although Thailand is considered species-rich, only a small number of potential bioresources has been investigated. This article briefly describes the pathogenesis of 2 infectious diseases, malaria and TB, and modern medicines employed in chemotherapy. Diversities of Thai flora and fungi and their chemical constituents with antagonistic properties against these 2 diseases are described in detail. Similarly, anti-inflammatory compounds, mostly cyclooxygenase (COX) inhibitors, are also described herein to demonstrate the potential of Thai bioresources to provide a wide array of compounds for treatment of diseases of a different nature.
Collapse
Affiliation(s)
- George A Gale
- King Mongkut's University of Technology Thonburi, School of Bioresources and Technology, Conservation Ecology Program, 83 Moo 8, Thakham, Bangkhuntien, Bangkok, Thailand
| | | | | | | | | | | | | |
Collapse
|
184
|
Evaluación de la prueba rápida inmunocromatográfica Binax NOW® ICT Pf/Pv para el diagnóstico del paludismo en un área endémica de Colombia. BIOMEDICA 2007. [DOI: 10.7705/biomedica.v27i2.218] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
185
|
Oliveira MF, Gandara ACP, Braga CMS, Silva JR, Mury FB, Dansa-Petretski M, Menezes D, Vannier-Santos MA, Oliveira PL. Heme crystallization in the midgut of triatomine insects. Comp Biochem Physiol C Toxicol Pharmacol 2007; 146:168-174. [PMID: 17254848 DOI: 10.1016/j.cbpc.2006.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Revised: 10/26/2006] [Accepted: 12/08/2007] [Indexed: 11/15/2022]
Abstract
Hemozoin (Hz) is a heme crystal produced by several blood-feeding organisms in order to detoxify free heme released upon hemoglobin (Hb) digestion. Here we show that heme crystallization also occurs in three species of triatomine insects. Ultraviolet-visible and infrared light absorption spectra of insoluble pigments isolated from the midgut of three triatomine species Triatoma infestans, Dipetalogaster maximus and Panstrongylus megistus indicated that all produce Hz. Morphological analysis of T. infestans and D. maximus midguts revealed the close association of Hz crystals to perimicrovillar membranes and also as multicrystalline assemblies, forming nearly spherical structures. Heme crystallization was promoted by isolated perimicrovillar membranes from all three species of triatomine bugs in vitro in heat-sensitive reactions. In conclusion, the data presented here indicate that Hz formation is an ancestral adaptation of Triatominae to a blood-sucking habit and that the presence of perimicrovillar membranes plays a central role in this process.
Collapse
Affiliation(s)
- Marcus F Oliveira
- Instituto de Bioquímica Médica, Programa de Biotecnologia e Biologia Molecular, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, RJ, 21941-590, Brazil.
| | - Ana Caroline P Gandara
- Instituto de Bioquímica Médica, Programa de Biotecnologia e Biologia Molecular, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, RJ, 21941-590, Brazil
| | - Cláudia M S Braga
- Petrobrás/CENPES, Divisão de Química, Setor de Química Orgânica, Cidade Universitária, Rio de Janeiro, RJ, 21949-900, Brazil
| | - José R Silva
- Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, 28013-602, Brazil
| | - Flavia B Mury
- Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, 28013-602, Brazil
| | - Marílvia Dansa-Petretski
- Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, RJ, 28013-602, Brazil
| | - Diego Menezes
- Centro de Pesquisas Gonçalo Moniz, Fiocruz, Salvador, BA, Brazil
| | | | - Pedro L Oliveira
- Instituto de Bioquímica Médica, Programa de Biotecnologia e Biologia Molecular, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, RJ, 21941-590, Brazil
| |
Collapse
|
186
|
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.
Collapse
Affiliation(s)
- Nguyen Tien Huy
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Kyoto, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
187
|
Silva JR, Mury FB, Oliveira MF, Oliveira PL, Silva CP, Dansa-Petretski M. Perimicrovillar membranes promote hemozoin formation into Rhodnius prolixus midgut. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2007; 37:523-31. [PMID: 17517329 DOI: 10.1016/j.ibmb.2007.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Revised: 01/09/2007] [Accepted: 01/12/2007] [Indexed: 05/15/2023]
Abstract
Rhodnius prolixus is a hematophagous insect that ingests large quantities of blood in each blood-feeding session. This ingested blood provides important nutrients to sustain the insect's oogenesis and metabolic pathways. During the digestive process, however, huge amounts of heme are generated as a consequence of the hemoglobin breakdown. Heme is an extremely dangerous molecule, since it can generate reactive oxygen species in the presence of oxygen that impair the normal metabolism of the insect. Part of the hemoglobin-derived heme can associate with the perimicrovillar membranes (PMM) in the gut lumen of R. prolixus; in this study we demonstrate the participation of the PMM in a heme detoxification process. These membranes were able to successfully induce heme aggregation into hemozoin (Hz). Heme aggregation was not dependent on the erythrocyte membranes, since the contribution of these membranes to the process was negligible, demonstrating that the ability to induce heme aggregation is a feature of the PMM, possibly representing a pre-adaptation of the hemipterans to feeding on blood.
Collapse
Affiliation(s)
- José R Silva
- Laboratório de Química e Função de Proteínas e Peptídeos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Av Alberto Lamego, 2000, Campos dos Goytacazes, Brazil
| | | | | | | | | | | |
Collapse
|
188
|
Penet MF, Kober F, Confort-Gouny S, Le Fur Y, Dalmasso C, Coltel N, Liprandi A, Gulian JM, Grau GE, Cozzone PJ, Viola A. Magnetic resonance spectroscopy reveals an impaired brain metabolic profile in mice resistant to cerebral malaria infected with Plasmodium berghei ANKA. J Biol Chem 2007; 282:14505-14. [PMID: 17369263 DOI: 10.1074/jbc.m608035200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Malaria is a major cause of morbidity and mortality with an annual death toll exceeding one million. Severe malaria is a complex multisystem disorder, including one or more of the following complications: cerebral malaria, anemia, acidosis, jaundice, respiratory distress, renal insufficiency, coagulation anomalies, and hyperparasitemia. Using a combined in vivo/in vitro metabolic-based approach, we investigated the putative pathogenic effects of Plasmodium berghei ANKA on brain, in a mouse strain developing malaria but resistant to cerebral malaria. The purpose was to determine whether the infection could cause a brain dysfunction distinct from the classic cerebral syndrome. Mice resistant to cerebral malaria were infected with P. berghei ANKA and explored during both the symptomless and the severe stage of the disease by using in vivo brain magnetic resonance imaging and spectroscopy. The infected mice did not present the lesional and metabolic hallmarks of cerebral malaria. However, brain dysfunction caused by anemia, parasite burden, and hepatic damage was evidenced. We report an increase in cerebral blood flow, a process allowing temporary maintenance of oxygen supply to brain despite anemia. Besides, we document metabolic anomalies affecting choline-derived compounds, myo-inositol, glutamine, glycine, and alanine. The choline decrease appears related to parasite proliferation. Glutamine, myo-inositol, glycine, and alanine variations together indicate a hepatic encephalopathy, a finding in agreement with the liver damage detected in mice, which is also a feature of the human disease. These results reveal the vulnerability of brain to malaria infection at the severe stage of the disease even in the absence of cerebral malaria.
Collapse
Affiliation(s)
- Marie-France Penet
- Centre de Résonance Magnétique Biologique et Médicale, Unité Mixte de Recherche (UMR) CNRS 6612, Facultéde Médecine la Timone, UniversitédelaMéditerranée, Marseille, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
189
|
Pisciotta J, Coppens I, Tripathi A, Scholl P, Shuman J, Bajad S, Shulaev V, Sullivan D. The role of neutral lipid nanospheres in Plasmodium falciparum haem crystallization. Biochem J 2007; 402:197-204. [PMID: 17044814 PMCID: PMC1783988 DOI: 10.1042/bj20060986] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The intraerythrocytic malaria parasite constructs an intracellular haem crystal, called haemozoin, within an acidic digestive vacuole where haemoglobin is degraded. Haem crystallization is the target of the widely used antimalarial quinoline drugs. The intracellular mechanism of molecular initiation of haem crystallization, whether by proteins, polar membrane lipids or by neutral lipids, has not been fully substantiated. In the present study, we show neutral lipid predominant nanospheres, which envelop haemozoin inside Plasmodium falciparum digestive vacuoles. Subcellular fractionation of parasite-derived haemozoin through a dense 1.7 M sucrose cushion identifies monoacylglycerol and diacylglycerol neutral lipids as well as some polar lipids in close association with the purified haemozoin. Global MS lipidomics detects monopalmitic glycerol and monostearic glycerol, but not mono-oleic glycerol, closely associated with haemozoin. The complex neutral lipid mixture rapidly initiates haem crystallization, with reversible pH-dependent quinoline inhibition associated with quinoline entry into the neutral lipid microenvironment. Neutral lipid nanospheres both enable haem crystallization in the presence of high globin concentrations and protect haem from H2O2 degradation. Conceptually, the present study shifts the intracellular microenvironment of haem crystallization and quinoline inhibition from a polar aqueous location to a non-polar neutral lipid nanosphere able to exclude water for efficient haem crystallization.
Collapse
Affiliation(s)
- John M. Pisciotta
- *Malaria Research Institute, W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, U.S.A
| | - Isabelle Coppens
- *Malaria Research Institute, W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, U.S.A
| | - Abhai K. Tripathi
- *Malaria Research Institute, W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, U.S.A
| | - Peter F. Scholl
- †Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, U.S.A
| | - Joel Shuman
- ‡Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, U.S.A
| | - Sunil Bajad
- ‡Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, U.S.A
| | - Vladimir Shulaev
- ‡Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, U.S.A
| | - David J. Sullivan
- *Malaria Research Institute, W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, U.S.A
- To whom correspondence should be addressed (email )
| |
Collapse
|
190
|
Kumar S, Guha M, Choubey V, Maity P, Bandyopadhyay U. Antimalarial drugs inhibiting hemozoin (β-hematin) formation: A mechanistic update. Life Sci 2007; 80:813-28. [PMID: 17157328 DOI: 10.1016/j.lfs.2006.11.008] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Revised: 10/24/2006] [Accepted: 11/06/2006] [Indexed: 11/30/2022]
Abstract
Digestion of hemoglobin in the food vacuole of the malaria parasite produces very high quantities of redox active toxic free heme. Hemozoin (beta-hematin) formation is a unique process adopted by Plasmodium sp. to detoxify free heme. Hemozoin formation is a validated target for most of the well-known existing antimalarial drugs and considered to be a suitable target to develop new antimalarials. Here we discuss the possible mechanisms of free heme detoxification in the malaria parasite and the mechanistic details of compounds, which offer antimalarial activity by inhibiting hemozoin formation. The chemical nature of new antimalarial compounds showing antimalarial activity through the inhibition of hemozoin formation has also been incorporated, which may help to design future antimalarials with therapeutic potential against multi-drug resistant malaria.
Collapse
Affiliation(s)
- Sanjay Kumar
- Division of Drug Target Discovery and Development, Central Drug Research Institute, Chatter Manzil Palace, Mahatma Gandhi Marg, Lucknow-226001, Uttar Pradesh, India
| | | | | | | | | |
Collapse
|
191
|
Huy NT, Maeda A, Uyen DT, Trang DTX, Sasai M, Shiono T, Oida T, Harada S, Kamei K. Alcohols induce beta-hematin formation via the dissociation of aggregated heme and reduction in interfacial tension of the solution. Acta Trop 2007; 101:130-8. [PMID: 17274939 DOI: 10.1016/j.actatropica.2007.01.001] [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] [Received: 10/27/2006] [Revised: 12/01/2006] [Accepted: 01/03/2007] [Indexed: 11/27/2022]
Abstract
The formation of the malarial pigment, a unique hemozoin crystal with unit cells comprised of heme dimers, has been proposed as an ideal target for antimalarial screening. The mechanism of beta-hematin formation (a synthetic crystal structurally identical to hemozoin) has been suggested that a hydrophobic interaction is needed to solubilize heme, but this hypothesis needs further evidence. Direct study of the process of hemozoin formation in the malarial food vacuole has not been performed, due to complicated groups of lipids and proteins. To overcome this difficulty and to explore the environmental conditions for beta-hematin formation, we systematically studied beta-hematin formation induced by a series of small normal alcohols (methanol, ethanol, n-propanol, and n-butanol), which are structurally similar. For the first time, the ability of beta-hematin inducer could be evaluated by its concentration that is required to enhance heme crystallization by 50% (EC(50) values). These values provide a rapid and convenient tool for comparing the ability of initiators in beta-hematin formation. Our results showed that the ability of alcohols to induce beta-hematin formation in the order: n-butanol>n-propanol>ethanol>methanol. The induction of beta-hematin formation by alcohols is related with their degree of hydrophobicity and ability to solubilize heme, suggesting that the dissociation of aggregated heme by alcohols is a major factor in beta-hematin formation. In addition, alcohols can reduce the surface tension of a solution, thus lowering the energy barrier for creating critical nuclei.
Collapse
Affiliation(s)
- Nguyen T Huy
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan; Venture Laboratory, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
192
|
Huy NT, Uyen DT, Maeda A, Trang DTX, Oida T, Harada S, Kamei K. Simple colorimetric inhibition assay of heme crystallization for high-throughput screening of antimalarial compounds. Antimicrob Agents Chemother 2006; 51:350-3. [PMID: 17088494 PMCID: PMC1797674 DOI: 10.1128/aac.00985-06] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Current assays for screening new antimalarials need initiators of beta-hematin formation that require laborious preparation, special devices, and substrates. In this study, based on reduction of heme absorption in beta-hematin formation, we developed a simple colorimetric assay using Tween 20 as an initiator and a microplate reader for high-throughput screening of inhibitors of beta-hematin formation.
Collapse
Affiliation(s)
- Nguyen Tien Huy
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | | | | | | | | | | | | |
Collapse
|
193
|
|
194
|
de Villiers KA, Kaschula CH, Egan TJ, Marques HM. Speciation and structure of ferriprotoporphyrin IX in aqueous solution: spectroscopic and diffusion measurements demonstrate dimerization, but not μ-oxo dimer formation. J Biol Inorg Chem 2006; 12:101-17. [PMID: 16972088 DOI: 10.1007/s00775-006-0170-1] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Accepted: 08/25/2006] [Indexed: 11/29/2022]
Abstract
Changes in epsilon (393) (the Soret band) of aqueous ferriprotoporphyrin IX [Fe(III)PPIX] with concentration indicate that it dimerizes, but does not form higher aggregates. Diffusion measurements support this observation. The diffusion coefficient of aqueous Fe(III)PPIX is half that of the hydrated monomeric dicyano complex. Much of the apparent instability of aqueous Fe(III)PPIX solutions could be attributed to adsorption onto glass and plastic surfaces. However, epsilon (347) was found to be independent of the aggregation state of the porphyrin and was used to correct for the effects of adsorption. The UV-vis spectrum of the aqueous dimer is not consistent with that expected for a mu-oxo dimer and the (1)H NMR spectrum is characteristic of five-coordinate, high-spin Fe(III)PPIX. Magnetic susceptibility measurements using the Evans method showed that there is no antiferromagnetic coupling in the dimer. By contrast, when the mu-oxo dimer is induced in 10% aqueous pyridine, characteristic UV-vis and (1)H NMR spectra of this species are observed and the magnetic moment is consistent with strong antiferromagnetic coupling. We propose a model in which the spontaneously formed aqueous Fe(III)PPIX dimer involves noncovalent interaction of the unligated faces of two five-coordinate H(2)O/HO-Fe(III)PPIX molecules, with the axial H(2)O/OH(-) ligands directed outwards. This arrangement is consistent with the crystal structures of related five-coordinate iron(III) porphyrins and accounts for the observed pH dependence of the dimerization constant and the spectra of the monomer and dimer. Structures for the aqueous dimer are proposed on the basis of molecular dynamics/simulated annealing calculations using a force field previously developed for modeling metalloporphyrins.
Collapse
Affiliation(s)
- Katherine A de Villiers
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch, 7701, South Africa
| | | | | | | |
Collapse
|
195
|
Egan TJ, Chen JYJ, de Villiers KA, Mabotha TE, Naidoo KJ, Ncokazi KK, Langford SJ, McNaughton D, Pandiancherri S, Wood BR. Haemozoin (β-haematin) biomineralization occurs by self-assembly near the lipid/water interface. FEBS Lett 2006; 580:5105-10. [PMID: 16956610 DOI: 10.1016/j.febslet.2006.08.043] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Accepted: 08/08/2006] [Indexed: 11/30/2022]
Abstract
Several blood-feeding organisms, including the malaria parasite detoxify haem released from host haemoglobin by conversion to the insoluble crystalline ferriprotoporphyrin IX dimer known as haemozoin. To date the mechanism of haemozoin formation has remained unknown, although lipids or proteins have been suggested to catalyse its formation. We have found that beta-haematin (synthetic haemozoin) forms rapidly under physiologically realistic conditions near octanol/water, pentanol/water and lipid/water interfaces. Molecular dynamics simulations show that a precursor of the haemozoin dimer forms spontaneously in the absence of the competing hydrogen bonds of water, demonstrating that this substance probably self-assembles near a lipid/water interface in vivo.
Collapse
Affiliation(s)
- Timothy J Egan
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch 7701, South Africa.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
196
|
Egan TJ, Tshivhase MG. Kinetics of beta-haematin formation from suspensions of haematin in aqueous benzoic acid. Dalton Trans 2006:5024-32. [PMID: 17060988 DOI: 10.1039/b610866k] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Kinetics of beta-haematin (synthetic malaria pigment) formation from haematin have been studied in the presence of aqueous benzoic acid and derivatives of benzoic acid. Formation of the beta-haematin product is demonstrated by X-ray diffraction and IR spectroscopy. Reactions were followed by determining the fraction of unreacted haematin at various time points during the process via reaction of extracted aliquots with pyridine. The kinetics can be fitted to the Avrami equation, indicating that the process involves nucleation and growth. Reaction kinetics in stirred benzoic acid are similar to those previously observed in acetic acid, except that benzoic acid is far more active in promoting the reaction than acetic acid. The reaction reaches completion within 2 h in the presence of 0.050 M benzoic acid (pH 4.5, 60 degrees C). This compares with 1 h in the presence of 4.5 M acetic acid and 4 h in the presence of 2 M acetic acid. The reaction rate in benzoic acid is not affected if the stirring rate is decreased to zero, but very vigorous stirring appears to disrupt nucleation. The rate constant for beta-haematin formation in benzoic acid has a linear dependence on benzoic acid concentration and follows Arrhenius behaviour with temperature. There is a bell-shaped dependence on pH. This suggests that the haematin species in which one propionate group is protonated and the other is deprotonated is optimal for beta-haematin formation. When the reaction is conducted in para-substituted benzoic acid derivatives, the log of the rate constant increases linearly with the Hammett constant. These findings suggest that the role of the carboxylic acid may be to disrupt hydrogen bonding and pi-stacking in haematin, facilitating conversion to beta-haematin. The large activation energy for conversion of precipitated haematin to beta-haematin suggests that the reaction in vivo most likely involves direct nucleation from solution and probably does not occur in aqueous medium.
Collapse
Affiliation(s)
- Timothy J Egan
- Department of Chemistry, University of Cape Town, South Africa.
| | | |
Collapse
|
197
|
Das P, Grewal JS, Chauhan VS. Interaction of Plasmodium falciparum histidine-rich protein II with human lymphocytes leads to suppression of proliferation, IFN-γ release, and CD69 expression. Parasitol Res 2006; 100:39-50. [PMID: 16788832 DOI: 10.1007/s00436-006-0228-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Accepted: 04/24/2006] [Indexed: 10/24/2022]
Abstract
The presence of histidine-rich protein II (HRP II) synthesized by Plasmodium falciparum in the plasma of malaria patients for longer periods even after parasite clearance raises questions about its extracellular functions. The present study was carried out to examine its influence on host immune system. Recombinant HRP-II protein was radiolabeled with (125)I to study the specific binding with T and B cells. We found that the binding of (125)I-HRP II with human T and B cells was specific, concentration dependent, saturable, and reversible. Scatchard plot analysis revealed two classes of binding sites for both T and B cells. For the T cells, the high affinity class had dissociation constant (K(d)) of 5.61x10(-11)M, and the low affinity class had a K(d) of 8.58x10(-11) M. For the B cells, the high and low affinity classes had a K(d) of 1.32x10(-11) and 2.84x10(-11) M, respectively. Dot-blot, autoradiography, and Western blot analysis also confirmed the specific binding of HRP II with lymphocytes. HRP II significantly inhibited (approximately 75%) T-cell rosette formation with sheep erythrocytes. HRP II also suppressed proliferation of T and B cells triggered by CD3 and LPS, respectively. We found a reduction in IFN-gamma release in T cells preincubated with HRP II. HRP II also reduced the CD69 expression on the T cells. In conclusion, HRP-II binding to human lymphocytes leads to suppression of some of their functions.
Collapse
Affiliation(s)
- Padmalaya Das
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, P.O. Box No. 10504, New Delhi, 110067, India.
| | | | | |
Collapse
|
198
|
Rathore D, Jani D, Nagarkatti R, Kumar S. Heme detoxification and antimalarial drugs – Known mechanisms and future prospects. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.ddstr.2006.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
199
|
Scholl PF, Tripathi AK, Sullivan DJ. Bioavailable iron and heme metabolism in Plasmodium falciparum. Curr Top Microbiol Immunol 2006; 295:293-324. [PMID: 16265896 DOI: 10.1007/3-540-29088-5_12] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Iron metabolism is essential for cell function and potentially toxic because iron can catalyze oxygen radical production. Malaria-attributable anemia and iron deficiency anemia coincide as being treatable diseases in the developing world. In absolute amounts, more than 95% of Plasmodium metal biochemistry occurs in the acidic digestive vacuole where heme released from hemoglobin catabolism forms heme crystals. The antimalarial quinolines interfere with crystallization. Despite the completion of the Plasmodium genome, many 'gene gaps' exist in components of the metal pathways described in mammalian or yeast cells. Present evidence suggests that parasite bioavailable iron originates from a labile erythrocyte cytosolic pool rather than from abundant heme iron. Indeed the parasite has to make its own heme within two separate organelles, the mitochondrion and the apicomplast. Paradoxically, despite the abundance of iron within the erythrocyte, iron chelators are cytocidal to the Plasmodium parasite. Hemozoin has become a sensitive biomarker for laser desorption mass spectrometry detection of Plasmodium infection in both mice and humans.
Collapse
Affiliation(s)
- P F Scholl
- Department of Environmental Health Sciences, Baltimore, MD 21205, USA
| | | | | |
Collapse
|
200
|
Rathore D, McCutchan TF, Sullivan M, Kumar S. Antimalarial drugs: current status and new developments. Expert Opin Investig Drugs 2006; 14:871-83. [PMID: 16022576 DOI: 10.1517/13543784.14.7.871] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Malaria continues to be a major threat in the developing world, with > 1 million clinical episodes and 3000 deaths every day. In the last century, malaria claimed between 150 and 300 million lives, accounting for 2 - 5% of all deaths. Currently approximately 40% of the world population resides in areas of active malaria transmission. The disease symptoms are most severe in young children and pregnant women. A total of 90% of the disease-associated mortality occurs in Subsaharan Africa, despite the fact that malaria is indigenous to most tropical regions. A licensed vaccine for malaria has not become a reality and antimalarial drugs are the only available method of treatment. Although chloroquine, the first synthetically developed antimalarial, proved to be an almost magical cure for > 30 years, the emergence and spread of chloroquine-resistant parasites has made it virtually ineffective in most parts of the world. Currently, artemisinin, a plant-derived antimalarial, is the only available drug that is globally effective against the parasite. Although several new drugs have been introduced in the past 30 years, widespread or isolated cases of resistance indicate that their window of effectiveness will be limited. Thus, there is an urgent need to develop new therapeutics and regimens for malaria control. This article presents an overview of the currently available antimalarial chemotherapy options and the efforts being undertaken to develop new drugs based on both the recent technological advances and modifications to the old remedies, and on combination therapies.
Collapse
Affiliation(s)
- Dharmendar Rathore
- Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Washington Street, Blacksburg, VA 24061, USA
| | | | | | | |
Collapse
|