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Mahanta PJ, Lhouvum K. Plasmodium falciparum proteases as new drug targets with special focus on metalloproteases. Mol Biochem Parasitol 2024; 258:111617. [PMID: 38554736 DOI: 10.1016/j.molbiopara.2024.111617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 02/15/2024] [Accepted: 03/10/2024] [Indexed: 04/02/2024]
Abstract
Malaria poses a significant global health threat particularly due to the prevalence of Plasmodium falciparum infection. With the emergence of parasite resistance to existing drugs including the recently discovered artemisinin, ongoing research seeks novel therapeutic avenues within the malaria parasite. Proteases are promising drug targets due to their essential roles in parasite biology, including hemoglobin digestion, merozoite invasion, and egress. While exploring the genomic landscape of Plasmodium falciparum, it has been revealed that there are 92 predicted proteases, with only approximately 14 of them having been characterized. These proteases are further distributed among 26 families grouped into five clans: aspartic proteases, cysteine proteases, metalloproteases, serine proteases, and threonine proteases. Focus on metalloprotease class shows further role in organelle processing for mitochondria and apicoplasts suggesting the potential of metalloproteases as viable drug targets. Holistic understanding of the parasite intricate life cycle and identification of potential drug targets are essential for developing effective therapeutic strategies against malaria and mitigating its devastating global impact.
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Affiliation(s)
| | - Kimjolly Lhouvum
- Department of Biotechnology, National Institute of Technology, Arunachal Pradesh, India.
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Zhao ZC, Jiang MY, Huang JH, Lin C, Guo WL, Zhong ZH, Huang QQ, Liu SL, Deng HW, Zhou YC. Honokiol induces apoptosis-like death in Cryptocaryon irritans Tomont. Parasit Vectors 2023; 16:287. [PMID: 37587480 PMCID: PMC10428556 DOI: 10.1186/s13071-023-05910-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 07/31/2023] [Indexed: 08/18/2023] Open
Abstract
BACKGROUND Cryptocaryon irritans, a common parasite in tropical and subtropical marine teleost fish, has caused serious harm to the marine aquaculture industry. Honokiol was proven to induce C. irritans tomont cytoplasm shrinkage and death in our previous study, but the mechanism by which it works remains unknown. METHODS In this study, the changes of apoptotic morphology and apoptotic ratio were detected by microscopic observation and AnnexinV-FITC/PI staining. The effects of honokiol on intracellular calcium ([Ca2+]i) concentration, mitochondrial membrane potential (ΔΨm), reactive oxygen species (ROS), quantity of DNA fragmentations (QDF) and caspase activities were detected by Fluo-3 staining, JC-1 staining, DCFH-DA staining, Tunel method and caspase activity assay kit. The effects of honokiol on mRNA expression levels of 61 apoptosis-related genes in tomonts of C. irritans were detected by real-time PCR. RESULTS The results of the study on the effects of honokiol concentration on C. irritans tomont apoptosis-like death showed that the highest levels of prophase apoptosis-like death rate (PADR), [Ca2+]i concentration, ROS, the activities of caspase-3/9 and the lowest necrosis ratio (NER) were obtained at a concentration of 1 μg/ml, which was considered the most suitable for inducing C. irritans tomont apoptosis-like death. When C. irritans tomonts were treated with 1 μg/ml honokiol, the [Ca2+]i concentration began to increase significantly at 1 h. Following this, the ROS, QDF and activities of caspase-3/9 began to increase significantly, and the ΔΨm began to decrease significantly at 2 h; the highest PADR was obtained at 4 h. The mRNA expression of 14 genes was significantly upregulated during honokiol treatment. Of these genes, itpr2, capn1, mc, actg1, actb, parp2, traf2 and fos were enriched in the pathway related to apoptosis induced by endoplasmic reticulum (ER) stress. CONCLUSIONS This article shows that honokiol can induce C. irritans tomont apoptosis-like death. These results suggest that honokiol may disrupt [Ca2+]i homeostasis in ER and then induce C. irritans tomont apoptosis-like death by caspase cascade or mitochondrial pathway, which might represent a novel therapeutic intervention for C. irritans infection.
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Affiliation(s)
- Zi-Chen Zhao
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, Haikou, 570228, People's Republic of China
- School of Life Sciences, Hainan University, Haikou, 570228, People's Republic of China
| | - Man-Yi Jiang
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, Haikou, 570228, People's Republic of China
| | - Ji-Hui Huang
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, Haikou, 570228, People's Republic of China
- Technology Center of Haikou Customs District, Haikou, 570105, People's Republic of China
| | - Chuan Lin
- Aquaculture Department, Hainan Agriculture School, Haikou, 571101, People's Republic of China
| | - Wei-Liang Guo
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, Haikou, 570228, People's Republic of China.
| | - Zhi-Hong Zhong
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, Haikou, 570228, People's Republic of China
| | - Qing-Qin Huang
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, Haikou, 570228, People's Republic of China
| | - Shao-Long Liu
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, Haikou, 570228, People's Republic of China
| | - Heng-Wei Deng
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, Haikou, 570228, People's Republic of China
| | - Yong-Can Zhou
- Hainan Provincial Key Laboratory for Tropical Hydrobiology and Biotechnology, College of Marine Science, Hainan University, Haikou, 570228, People's Republic of China.
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Kumar S, Kapkoti DS, Mina PR, Gupta M, Kumar R, Kumar P, Pathak P, Bhakuni RS, Rout P, Pal A, Darokar MP. Effect of liquiritigenin on chloroquine accumulation in digestive vacuole leading to apoptosis-like death of chloroquine-resistant P. falciparum. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2023; 114:154738. [PMID: 36940579 DOI: 10.1016/j.phymed.2023.154738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 02/23/2023] [Accepted: 02/28/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND Malaria remains one of the major health concerns, especially in tropical countries. Although drugs such as artemisinin-based combinations are efficient for treating Plasmodium falciparum, the growing threat from multi-drug resistance has become a major challenge. Thus, there is a constant need to identify and validate new combinations to sustain current disease control strategies to overcome the challenge of drug resistance in the malaria parasites. To meet this demand, liquiritigenin (LTG) has been found to positively interact in combination with the existing clinically used drug chloroquine (CQ), which has become unfunctional due to acquired drug resistance. PURPOSE To evaluate the best interaction between LTG and CQ against CQ- resistant strain of P. falciparum. Furthermore, the in vivo antimalarial efficacy and possible mechanism of action of the best combination was also assessed. METHODS The in vitro anti-plasmodial potential of LTG against CQ- resistant strain K1 of P. falciparum was tested using Giemsa staining method. The behaviour of the combinations was evaluated using the fix ratio method and evaluated the interaction of LTG and CQ by calculating the fractional inhibitory concentration index (FICI). Oral toxicity study was carried out in a mice model. In vivo antimalarial efficacy of LTG alone and in combination with CQ was evaluated using a four-day suppression test in a mouse model. The effect of LTG on CQ accumulation was measured using HPLC and the rate of alkalinization of the digestive vacuole. Cytosolic Ca2+ level, mitochondrial membrane potential, caspase-like activity, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and Annexin V Apoptosis assay to assess anti-plasmodial potential. Proteomics analysis was evaluated by LC-MS/MS analysis. RESULTS LTG possesses anti-plasmodial activity on its own and it showed to be an adjuvant of CQ. In in vitro studies, LTG showed synergy with CQ only in the ratio (CQ: LTG-1:4) against CQ-resistant strain (K1) of P. falciparum. Interestingly, in vivo studies, LTG in combination with CQ showed higher chemo-suppression and enhanced mean survival time at much lower concentrations compared to individual doses of LTG and CQ against CQ- resistant strain (N67) of Plasmodium yoelli nigeriensis. LTG was found to increase the CQ accumulation into digestive vacuole, reducing the rate of alkalinization, in turn increasing cytosolic Ca2+ level, loss of mitochondrial potential, caspase-3 activity, DNA damage and externalization of phosphatidylserine of the membrane (in vitro). These observations indicate the involvement of apoptosis-like death of P. falciparum that might be due to the accumulation of CQ. CONCLUSION LTG showed synergy with CQ in the ratio LTG: CQ, 4:1) in vitro and was able to curtail the IC50 of CQ and LTG. Interestingly, in vivo in combination with CQ, LTG showed higher chemo-suppression as well as enhanced mean survival time at a much lower concentrations of both the partners as compared to an individual dose of CQ and LTG. Thus, synergistic drug combination offers the possibility to enhance CQ efficacy in chemotherapy.
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Affiliation(s)
- Saurabh Kumar
- Bioprospection and Product Development Division, CSIR- Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Deepak Singh Kapkoti
- Phytochemistry Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Pooja Rani Mina
- Bioprospection and Product Development Division, CSIR- Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Madhuri Gupta
- Phytochemistry Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Ravi Kumar
- Bioprospection and Product Development Division, CSIR- Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Parmanand Kumar
- Bioprospection and Product Development Division, CSIR- Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Priyanka Pathak
- Bioprospection and Product Development Division, CSIR- Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - R S Bhakuni
- Phytochemistry Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Prasant Rout
- Phytochemistry Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Anirban Pal
- Bioprospection and Product Development Division, CSIR- Central Institute of Medicinal and Aromatic Plants, Lucknow, India.
| | - Mahendra P Darokar
- Bioprospection and Product Development Division, CSIR- Central Institute of Medicinal and Aromatic Plants, Lucknow, India.
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Dual role of an essential HtrA2/Omi protease in the human malaria parasite: Maintenance of mitochondrial homeostasis and induction of apoptosis-like cell death under cellular stress. PLoS Pathog 2022; 18:e1010932. [DOI: 10.1371/journal.ppat.1010932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 11/09/2022] [Accepted: 10/17/2022] [Indexed: 11/11/2022] Open
Abstract
Members of the HtrA family of serine proteases are known to play roles in mitochondrial homeostasis as well as in programmed cell death. Mitochondrial homeostasis and metabolism are crucial for the survival and propagation of the malaria parasite within the host. Here we have functionally characterized a Plasmodium falciparum HtrA2 (PfHtrA2) protein, which harbours trypsin-like protease activity that can be inhibited by its specific inhibitor, ucf-101. A transgenic parasite line was generated, using the HA-glmS C-terminal tagging approach, for localization as well as for inducible knock-down of PfHtrA2. The PfHtrA2 was localized in the parasite mitochondrion during the asexual life cycle. Genetic ablation of PfHtrA2 caused significant parasite growth inhibition, decreased replication of mtDNA, increased mitochondrial ROS production, caused mitochondrial fission/fragmentation, and hindered parasite development. However, the ucf-101 treatment did not affect the parasite growth, suggesting the non-protease/chaperone role of PfHtrA2 in the parasite. Under cellular stress conditions, inhibition of PfHtrA2 by ucf-101 reduced activation of the caspase-like protease as well as parasite cell death, suggesting the involvement of protease activity of PfHtrA2 in apoptosis-like cell death in the parasite. Under these cellular stress conditions, the PfHtrA2 gets processed but remains localized in the mitochondrion, suggesting that it acts within the mitochondrion by cleaving intra-mitochondrial substrate(s). This was further supported by trans-expression of PfHtrA2 protease domain in the parasite cytosol, which was unable to induce any cell death in the parasite. Overall, we show the specific roles of PfHtrA2 in maintaining mitochondrial homeostasis as well as in regulating stress-induced cell death.
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Kumari V, Prasad KM, Kalia I, Sindhu G, Dixit R, Rawat DS, Singh OP, Singh AP, Pandey KC. Dissecting The role of Plasmodium metacaspase-2 in malaria gametogenesis and sporogony. Emerg Microbes Infect 2022; 11:938-955. [PMID: 35264080 PMCID: PMC8973346 DOI: 10.1080/22221751.2022.2052357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The family of apicomplexan specific proteins contains caspases–like proteins called “metacaspases”. These enzymes are present in the malaria parasite but absent in human; therefore, these can be explored as potential drug targets. We deleted the MCA-2 gene from Plasmodium berghei genome using a gene knockout strategy to decipher its precise function. This study has identified that MCA-2 plays an important role in parasite transmission since it is critical for the formation of gametocytes and for maintaining an appropriate number of infectious sporozoites required for sporogony. It is noticeable that a significant reduction in gametocyte, oocysts, ookinete and sporozoites load along with a delay in hepatocytes invasion were observed in the MCA-2 knockout parasite. Furthermore, a study found the two MCA-2 inhibitory molecules known as C-532 and C-533, which remarkably inhibited the MCA-2 activity, abolished the in vitro parasite growth, and also impaired the transmission cycle of P. falciparum and P. berghei in An. stephensi. Our findings indicate that the deletion of MCA-2 hampers the Plasmodium development during erythrocytic and exo-erythrocytic stages, and its inhibition by C-532 and C-533 critically affects the malaria transmission biology.
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Affiliation(s)
- Vandana Kumari
- ICMR-National Institute of Malaria Research, New Delhi, India
| | | | | | | | - Rajnikant Dixit
- ICMR-National Institute of Malaria Research, New Delhi, India
| | - Diwan S Rawat
- Depatment of Chemistry, University of Delhi, New Delhi, India
| | - O P Singh
- ICMR-National Institute of Malaria Research, New Delhi, India
| | - Agam P Singh
- National Institute of Immunology, New Delhi, India
| | - Kailash C Pandey
- ICMR-National Institute of Malaria Research, New Delhi, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad Uttar Pradesh, UP, India
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Mohapatra AD, Zuromski J, Kurtis J. Assessing PfGARP-Mediated Apoptosis of Blood-Stage Plasmodium falciparum Parasites. Methods Mol Biol 2022; 2470:659-672. [PMID: 35881381 DOI: 10.1007/978-1-0716-2189-9_49] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Apoptosis is conventionally regarded as an evolutionarily conserved and genetically controlled process of programmed cell death confined to metazoan organisms. However, recently, conserved features of apoptosis have also been demonstrated in unicellular eukaryotes (Holzmuller et al. Parasitology 132:S19-S32, 2006; Le Chat et al. Mol Biochem Parasitol 153:41-47, 2007; Madeo et al. Curr Opin Microbiol 7:655-660, 2004; Welburn et al. Parasitology 132:S7-S18, 2006; Jensen et al. Science 216:1230-1233, 1982) including malaria parasites (Al-Olayan et al. Int J Parasitol 32:1133-1143, 2002; Ch'ng et al. Cell Death Dis 1:e26, 2010; Meslin et al. J Infect Dis 195:1852-1859, 2007; Picot et al. Trans R Soc Trop Med Hyg 91:590-591, 1997; Raj et al. Nature 582:104-108, 2020). P. falciparum glutamic-acid-rich protein (PfGARP) is an antigen of 80 kDa that is uniquely expressed on the exofacial surface of red blood cells (RBCs) infected by early-to-late-trophozoite-stage P. falciparum parasites (Raj et al. Nature 582:104-108, 2020). We have recently demonstrated that antibodies against PfGARP bind to the PfGARP displayed on the surface of P. falciparum trophozoite-infected RBCs and trigger apoptosis in the intracellular parasites (Raj et al. Nature 582:104-108, 2020). This is the first demonstration of antibody-induced apoptosis in blood-stage malaria parasites and is characterized by several conserved features such as crisis form morphology, loss of mitochondrial membrane potential, loss of integrity of food vacuole, activation of caspase-like cysteine proteases, and fragmentation of chromosomal DNA. Here we describe the assays used to detect these features of apoptosis in the mature blood stage of malaria parasites.
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Affiliation(s)
- Alok Das Mohapatra
- Department of Pathology and Laboratory Medicine, Brown University Medical School, Providence, RI, USA
| | - Jenna Zuromski
- Department of Pathology and Laboratory Medicine, Brown University Medical School, Providence, RI, USA
| | - Jonathan Kurtis
- Department of Pathology and Laboratory Medicine, Brown University Medical School, Providence, RI, USA.
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Šoln K, Klemenčič M. Determination of Caspase-Like Activities in Roots by the Use of Fluorogenic Substrates. Methods Mol Biol 2022; 2447:119-126. [PMID: 35583777 DOI: 10.1007/978-1-0716-2079-3_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Activity of proteases in tissues can be influenced by various intrinsic and extrinsic factors. One of the activities that is regularly monitored in organisms ranging from prokaryotes to metazoans is the -aspase-like activity: activity of proteases, which cleave their substrates after the negatively charged amino acid residues, especially the aspartic acid. This activity is also known as the caspase-like activity, since the caspases, metazoan cysteine proteases, are one of the best characterized proteases with Asp-directed activities. Plants do not contain caspases; however, various plant proteases have been shown to exhibit caspase-like activity including saspases, phytaspases, and legumains (VPEs). The activity of these proteases can change in plants in response to stress. Here we present a simple method for monitoring of the caspase-like protease activity in roots, which have been treated with allelopathic extracts, using a set of commercially available caspase substrates. We show that activity towards some, but not all, caspase substrates is upregulated in treated but not control samples. The protocol can be used also for other plant tissues as well as for other stressors.
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Affiliation(s)
- Katarina Šoln
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Marina Klemenčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia.
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Chia W, Gomez-Lorenzo MG, Castellote I, Tong JX, Chandramohanadas R, Thu Chu TT, Shen W, Go ML, de Cozar C, Crespo B, Almela MJ, Neria-Serrano F, Franco V, Gamo FJ, Tan KSW. High-Content Phenotypic Screen of a Focused TCAMS Drug Library Identifies Novel Disruptors of the Malaria Parasite Calcium Dynamics. ACS Chem Biol 2021; 16:2348-2372. [PMID: 34609851 DOI: 10.1021/acschembio.1c00512] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The search for new antimalarial drugs with unexplored mechanisms of action is currently one of the main objectives to combat the resistance already in the clinic. New drugs should target specific mechanisms that once initiated lead inevitably to the parasite's death and clearance and cause minimal toxicity to the host. One such new mode of action recently characterized is to target the parasite's calcium dynamics. Disruption of the calcium homeostasis is associated with compromised digestive vacuole membrane integrity and release of its contents, leading to programmed cell death-like features characterized by loss of mitochondrial membrane potential and DNA degradation. Intriguingly, chloroquine (CQ)-treated parasites were previously reported to exhibit such cellular features. Using a high-throughput phenotypic screen, we identified 158 physiological disruptors (hits) of parasite calcium distribution from a small subset of approximately 3000 compounds selected from the GSK TCAMS (Tres Cantos Anti-Malarial Set) compound library. These compounds were then extensively profiled for biological activity against various CQ- and artemisinin-resistant Plasmodium falciparum strains and stages. The hits were also examined for cytotoxicity, speed of antimalarial activity, and their possible inhibitory effects on heme crystallization. Overall, we identified three compounds, TCMDC-136230, -125431, and -125457, which were potent in inducing calcium redistribution but minimally inhibited heme crystallization. Molecular superimposition of the molecules by computational methods identified a common pharmacophore, with the best fit assigned to TCMDC-125457. There were low cytotoxicity or CQ cross-resistance issues for these three compounds. IC50 values of these three compounds were in the low micromolar range. In addition, TCMDC-125457 demonstrated high efficacy when pulsed in a single-dose combination with artesunate against tightly synchronized artemisinin-resistant ring-stage parasites. These results should add new drug options to the current armament of antimalarial drugs as well as provide promising starting points for development of drugs with non-classical modes of action.
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Affiliation(s)
- Wanni Chia
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, and Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, S117545, Singapore
| | - Maria G. Gomez-Lorenzo
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Isabel Castellote
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Jie Xin Tong
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, and Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, S117545, Singapore
| | - Rajesh Chandramohanadas
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, and Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, S117545, Singapore
| | - Trang Thi Thu Chu
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, and Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, S117545, Singapore
| | - Wanxiang Shen
- Department of Pharmacy, National University of Singapore, 18 Science Drive 4, S117543, Singapore
| | - Mei Lin Go
- Department of Pharmacy, National University of Singapore, 18 Science Drive 4, S117543, Singapore
| | - Cristina de Cozar
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Benigno Crespo
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Maria J. Almela
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Fernando Neria-Serrano
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Virginia Franco
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Francisco-Javier Gamo
- Global Health Discovery Incubator Unit, Global Health R&D, GlaxoSmithKline, Severo Ochoa 2, Tres Cantos, Madrid 28760, Spain
| | - Kevin S. W. Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, and Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, S117545, Singapore
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Sheriff O, Yaw A, Lai SK, Loo HL, Sze SK, Preiser PR. Plasmodium falciparum replication factor C subunit 1 is involved in genotoxic stress response. Cell Microbiol 2020; 23:e13277. [PMID: 33040440 DOI: 10.1111/cmi.13277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/05/2020] [Accepted: 10/06/2020] [Indexed: 02/03/2023]
Abstract
About half the world's population is at risk of malaria, with Plasmodium falciparum malaria being responsible for the most malaria related deaths globally. Antimalarial drugs such as chloroquine and artemisinin are directed towards the proliferating intra-erythrocytic stages of the parasite, which is responsible for all the clinical symptoms of the disease. These antimalarial drugs have been reported to function via multiple pathways, one of which induces DNA damage via the generation of free radicals and reactive oxygen species. An urgent need to understand the mechanistic details of drug response and resistance is highlighted by the decreasing clinical efficacy of the front line drug, Artemisinin. The replication factor C subunit 1 is an important component of the DNA replication machinery and DNA damage response mechanism. Here we show the translocation of PfRFC1 from an intranuclear localisation to the nuclear periphery, indicating an orchestrated progression of distinct patterns of replication in the developing parasites. PfRFC1 responds to genotoxic stress via elevated protein levels in soluble and chromatin bound fractions. Reduction of PfRFC1 protein levels upon treatment with antimalarials suggests an interplay of replication, apoptosis and DNA repair pathways leading to cell death. Additionally, mislocalisation of the endogenously tagged protein confirmed its essential role in parasites' replication and DNA repair. This study provides key insights into DNA replication, DNA damage response and cell death in P. falciparum.
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Affiliation(s)
- Omar Sheriff
- School of Biological Sciences, Nanyang Technological University Singapore, Singapore, Singapore
| | - Aniweh Yaw
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Legon, Ghana
| | - Soak Kuan Lai
- School of Biological Sciences, Nanyang Technological University Singapore, Singapore, Singapore
| | - Hooi Linn Loo
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
| | - Siu Kwan Sze
- School of Biological Sciences, Nanyang Technological University Singapore, Singapore, Singapore
| | - Peter Rainer Preiser
- School of Biological Sciences, Nanyang Technological University Singapore, Singapore, Singapore.,Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
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Dangi P, Jain R, Mamidala R, Sharma V, Agarwal S, Bathula C, Thirumalachary M, Sen S, Singh S. Natural Product Inspired Novel Indole based Chiral Scaffold Kills Human Malaria Parasites via Ionic Imbalance Mediated Cell Death. Sci Rep 2019; 9:17785. [PMID: 31780808 PMCID: PMC6882913 DOI: 10.1038/s41598-019-54339-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 06/28/2019] [Indexed: 02/06/2023] Open
Abstract
Natural products offer an abundant source of diverse novel scaffolds that inspires development of next generation anti-malarials. With this vision, a library of scaffolds inspired by natural biologically active alkaloids was synthesized from chiral bicyclic lactams with steps/scaffold ratio of 1.7:1. On evaluation of library of scaffolds for their growth inhibitory effect against malaria parasite we found one scaffold with IC50 in low micro molar range. It inhibited parasite growth via disruption of Na+ homeostasis. P-type ATPase, PfATP4 is responsible for maintaining parasite Na+ homeostasis and is a good target for anti-malarials. Molecular docking with our scaffold showed that it fits well in the binding pocket of PfATP4. Moreover, inhibition of Na+-dependent ATPase activity by our potent scaffold suggests that it targets parasite by inhibiting PfATP4, leading to ionic imbalance. However how ionic imbalance attributes to parasite's death is unclear. We show that ionic imbalance caused by scaffold 7 induces autophagy that leads to onset of apoptosis in the parasite evident by the loss of mitochondrial membrane potential (ΔΨm) and DNA degradation. Our study provides a novel strategy for drug discovery and an insight into the molecular mechanism of ionic imbalance mediated death in malaria parasite.
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Affiliation(s)
- Poonam Dangi
- Department of Life Science, Shiv Nadar University, Gautam Buddha Nagar, 201314, India
| | - Ravi Jain
- Department of Life Science, Shiv Nadar University, Gautam Buddha Nagar, 201314, India
| | | | - Vijeta Sharma
- Department of Life Science, Shiv Nadar University, Gautam Buddha Nagar, 201314, India
| | - Shalini Agarwal
- International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Chandramohan Bathula
- Department of Chemistry, Shiv Nadar University, Gautam Buddha Nagar, 201314, India
| | - M Thirumalachary
- Jawaharlal Technological University, Kukatpally, 500072, Hyderabad, India
| | - Subhabrata Sen
- Department of Chemistry, Shiv Nadar University, Gautam Buddha Nagar, 201314, India
| | - Shailja Singh
- Department of Life Science, Shiv Nadar University, Gautam Buddha Nagar, 201314, India.
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India.
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11
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Reiling SJ, Rohrbach P. Uptake of a fluorescently tagged chloroquine analogue is reduced in CQ-resistant compared to CQ-sensitive Plasmodium falciparum parasites. Malar J 2019; 18:342. [PMID: 31590674 PMCID: PMC6781371 DOI: 10.1186/s12936-019-2980-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 09/28/2019] [Indexed: 11/11/2022] Open
Abstract
Background Chloroquine (CQ) was the drug of choice for decades in the treatment of falciparum malaria until resistance emerged. CQ is suggested to accumulate in the parasite’s digestive vacuole (DV), where it unfolds its anti-malarial properties. Discrepancies of CQ accumulation in CQ-sensitive (CQS) and CQ-resistant (CQR) strains are thought to play a significant role in drug susceptibility. Analysis of CQ transport and intracellular localization using a fluorescently tagged CQ analogue could provide much needed information to distinguish susceptible from resistant parasite strains. The fluorescently tagged CQ analogue LynxTag-CQ™GREEN (CQGREEN) is commercially available and was assessed for its suitability. Methods IC50 values were determined for both CQ and CQGREEN in two CQS and two CQR Plasmodium falciparum strains. Buffer solutions with varying pH were used to determine pH-dependent localization of CQGREEN in infected red blood cells. Before CQS or CQR parasites were exposed to different pH buffers, they were pre-loaded with varying concentrations of CQGREEN for up to 7 h. Intracellular accumulation was analysed using live cell confocal microscopy. CQGREEN uptake rates were determined for the cytosol and DV in the presence and absence of verapamil. Results In CQS strains, twofold higher IC50 values were determined for the CQGREEN analogue compared to CQ. No significant differences in IC50 values were observed in CQR strains. Addition of verapamil reversed drug resistance of CQR strains to both CQ and CQGREEN. Live cell imaging revealed that CQGREEN fluorescence was mainly seen in the cytosol of most parasites, independent of the concentration used. Incubation periods of up to 7 h did not influence intracellular localization of CQGREEN. Nevertheless, CQGREEN uptake rates in CQR strains were reduced by 50% compared to CQS strains. Conclusion Although fluorescence of CQGREEN was mainly seen in the cytosol of parasites, IC50 assays showed comparable efficacy of CQGREEN and CQ in parasite killing of CQS and CQR strains. Reduced uptake rates of CQGREEN in CQR strains compared to CQS strains indicate parasite-specific responses to CQGREEN exposure. The data contains valuable information when CQGREEN is used as an analogue for CQ.
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Affiliation(s)
- Sarah J Reiling
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Montreal, QC, H9X-3V9, Canada
| | - Petra Rohrbach
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Montreal, QC, H9X-3V9, Canada.
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12
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Vandana, Dixit R, Tiwari R, Katyal A, Pandey KC. Metacaspases: Potential Drug Target Against Protozoan Parasites. Front Pharmacol 2019; 10:790. [PMID: 31379569 PMCID: PMC6657590 DOI: 10.3389/fphar.2019.00790] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 06/18/2019] [Indexed: 02/05/2023] Open
Abstract
Among the numerous strategies/targets for controlling infectious diseases, parasites-derived proteases receive prime attention due to their essential contribution to parasite growth and development. Parasites produce a broad array of proteases, which are required for parasite entry/invasion, modification/degradation of host proteins for their nourishment, and activation of inflammation that ensures their survival to maintain infection. Presently, extensive research is focused on unique proteases termed as "metacaspases" (MCAs) in relation to their versatile functions in plants and non-metazoans. Such unique MCAs proteases could be considered as a potential drug target against parasites due to their absence in the human host. MCAs are cysteine proteases, having Cys-His catalytic dyad present in fungi, protozoa, and plants. Studies so far indicated that MCAs are broadly associated with apoptosis-like cell death, growth, and stress regulation in different protozoa. The present review comprises the important research outcomes from our group and published literature, showing the variable properties and function of MCAs for therapeutic purpose against infectious diseases.
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Affiliation(s)
- Vandana
- Host-Parasite Interaction Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India.,Dr Ambedkar Center for Biomedical Research, Delhi University, New Delhi, India
| | - Rajnikant Dixit
- Host-Parasite Interaction Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India
| | - Rajnarayan Tiwari
- Department of Biochemistry, ICMR-National Institute for Research in Environmental Health, Bhopal, India
| | - Anju Katyal
- Dr Ambedkar Center for Biomedical Research, Delhi University, New Delhi, India
| | - Kailash C Pandey
- Host-Parasite Interaction Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India.,Department of Biochemistry, ICMR-National Institute for Research in Environmental Health, Bhopal, India
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13
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Durán-Pérez SA, López-Moreno HS, Jiménez-Edeza M, Parra-Unda JR, Rangel-López E, Rendón-Maldonado JG. Upregulation of Cathepsin B-like Protease Activity During Apoptosis inGiardia duodenalis. CURR PROTEOMICS 2019. [DOI: 10.2174/1570164616666190204112452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background:In eukaryotic cells, apoptosis signaling pathways are controlled mainly by aspartic acid cysteine proteases (caspases). However, certain unicellular microorganisms, such as Giardia duodenalis, lack these proteins. Thus, other cysteine proteases may play an important role in the parasite apoptosis signaling pathway.Objective:To understand the effect of cathepsin B-like inhibition on the cell viability of Giardia duodenalis and its cell death process.Methods:Bioinformatics analysis was performed to identify apoptotic proteases. Analysis showed that cathepsin B-like protease genes from G. duodenalis were the best candidate. A homology modeling technique was used to explore in silico the inhibitory effect of E-64 against cathepsin B-like proteases from G. duodenalis genome and to examine the effect of curcumin on cathepsin B-like activity regulation. In addition, the effect of E-64 on parasite survival and DNA fragmentation was tested.Results:Eight cathepsin B-like protease coding genes were identified in silico. Interestingly, while these sequences lacked the cathepsin B characteristic occluding loop, they maintained the catalytic active- site responsible for cathepsin B activity, which was evidenced by the increase in the degradation of the Z-RR-AMC substrate, suggesting the upregulation of the activity of these proteins. Additionally, inhibition of E-64 against G. duodenalis trophozoites caused a decrease in DNA fragmentation compared to control cells and had a positive effect on parasite survival after exposure to curcumin.Conclusion:Overall, these results suggested that Giardia duodenalis might have a cell death mechanism in which cathepsin B-like proteases play an important role.
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Affiliation(s)
- Sergio Alonso Durán-Pérez
- Doctorate in Biotechnology, Faculty of Biological Chemistry Sciences, Autonomous University of Sinaloa, Calzada de las Americas Norte 2771, Bureaucrat, 80030 Culiacan, Sinaloa, Mexico
| | - Héctor Samuel López-Moreno
- Doctorate in Biotechnology, Faculty of Biological Chemistry Sciences, Autonomous University of Sinaloa, Calzada de las Americas Norte 2771, Bureaucrat, 80030 Culiacan, Sinaloa, Mexico
| | - Maribel Jiménez-Edeza
- Doctorate in Biomedical Sciences, Faculty of Biological Chemistry Sciences, Autonomous University of Sinaloa, Calzada de las Americas Norte 2771, Bureaucrat, 80030 Culiacan, Sinaloa, Mexico
| | - Jesús Ricardo Parra-Unda
- Doctorate in Biotechnology, Faculty of Biological Chemistry Sciences, Autonomous University of Sinaloa, Calzada de las Americas Norte 2771, Bureaucrat, 80030 Culiacan, Sinaloa, Mexico
| | - Edgar Rangel-López
- Laboratory of Amino Acids Exciters, National Institute of Neurology and Neurosurgery Manuel Velasco Suarez, Insurgentes Sur 3877, 14269, Mexico City, Mexico
| | - José Guadalupe Rendón-Maldonado
- Doctorate in Biotechnology, Faculty of Biological Chemistry Sciences, Autonomous University of Sinaloa, Calzada de las Americas Norte 2771, Bureaucrat, 80030 Culiacan, Sinaloa, Mexico
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14
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Correa R, Coronado L, Caballero Z, Faral-Tello P, Robello C, Spadafora C. Extracellular vesicles carrying lactate dehydrogenase induce suicide in increased population density of Plasmodium falciparum in vitro. Sci Rep 2019; 9:5042. [PMID: 30911042 PMCID: PMC6434017 DOI: 10.1038/s41598-019-41697-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 03/14/2019] [Indexed: 11/29/2022] Open
Abstract
Even with access to sufficient nutrients and atmosphere, Plasmodium falciparum can barely be cultured at maximum growth capacity in vitro conditions. Because of this behavior, it has been suggested that P. falciparum has self-regulatory mechanisms in response to density stress. Only recently has this process begun to be acknowledged and characteristics of a programmed cell death been assigned to the parasite at high parasitaemia in vitro cultures. In searching for death signals within the parasite community, we have found that extracellular vesicles (EVs) of P. falciparum from high parasitaemia cultures are able to induce programmed cell death processes in the population. A comparative proteomic analysis of EVs from low (EVL) and high (EVH) parasitaemia cultures was conducted, pointing to lactate dehydrogenase from P. falciparum (PfLDH) as the only parasite protein overexpressed in the later. Although the major function of P. falciparum lactate dehydrogenase (PfLDH) is the conversion of pyruvate to lactate, a key process in the production of energy in most living organisms, we investigated its possible role in the mechanism of parasite density control by intercellular signaling, given that PfLDH had already been listed as a component of extracellular vesicles of P. falciparum. In this study we present evidence of the EV-associated PfLDH regulation of parasite population by inducing apoptosis in highly parasitized cultures.
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Affiliation(s)
- Ricardo Correa
- Center of Cellular and Molecular Biology of Diseases, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP). City of Knowledge, Panama City, 0843-01103, Panama
- Department of Biotechnology, Acharya Nagarjuna University, Guntur, 522 510, A.P., India
- Sistema Nacional de Investigación, Secretaría Nacional de Ciencia, Tecnología e Innovación, Panama City, 0843-01103, Panama
| | - Lorena Coronado
- Center of Cellular and Molecular Biology of Diseases, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP). City of Knowledge, Panama City, 0843-01103, Panama
- Sistema Nacional de Investigación, Secretaría Nacional de Ciencia, Tecnología e Innovación, Panama City, 0843-01103, Panama
| | - Zuleima Caballero
- Center of Cellular and Molecular Biology of Diseases, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP). City of Knowledge, Panama City, 0843-01103, Panama
- Sistema Nacional de Investigación, Secretaría Nacional de Ciencia, Tecnología e Innovación, Panama City, 0843-01103, Panama
| | | | | | - Carmenza Spadafora
- Center of Cellular and Molecular Biology of Diseases, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP). City of Knowledge, Panama City, 0843-01103, Panama.
- Sistema Nacional de Investigación, Secretaría Nacional de Ciencia, Tecnología e Innovación, Panama City, 0843-01103, Panama.
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15
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Pandey SS, Singh S, Pathak C, Tiwari BS. "Programmed Cell Death: A Process of Death for Survival" - How Far Terminology Pertinent for Cell Death in Unicellular Organisms. J Cell Death 2018; 11:1179066018790259. [PMID: 30116103 PMCID: PMC6088462 DOI: 10.1177/1179066018790259] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 06/22/2018] [Indexed: 02/01/2023] Open
Abstract
Programmed cell death (PCD) is genetically regulated phenomenon of selective elimination of target cells that are either under pathological conditions or unwanted for organism’s normal growth and development due to other reasons. The process although being genetically controlled is physiological in nature that renders some hallmarks like blebs in the cell membrane, lobe formation in nuclear membrane, DNA nicks resulting to DNA ladder of 200 bp, and downstream activation of caspases. Moreover, as the process refers to the death of “targeted cell”, the term is exclusively suitable for multicellular organisms. Number of reports advocate similar type of cell death process in unicellular organisms. As cell death in unicellular organisms is also reflected by the signature of PCD obtained in metazoans, such cell death has been grouped under the broad category of PCD. It is pertinent to mention that by definition a unicellular organism is made of a single cell wherein it carries out all of its life processes. Using the term “Programmed Cell Death” with a preset “survival strategy of the organism” for unicellular organisms looks misnomer. Therefore, this correspondence argues and requests recommendation committee on cell death to revisit for the nomenclature of the cell death process in the unicellular organisms.
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Affiliation(s)
- Shiv Shanker Pandey
- Crop Protection Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Samer Singh
- Department of Microbial Biotechnology, Panjab University, Chandigarh, India
| | - Chandramani Pathak
- Plant Cell Biology & Biotechnology, Institute of Advanced Research (IAR), Gandhinagar, India
| | - Budhi Sagar Tiwari
- Plant Cell Biology & Biotechnology, Institute of Advanced Research (IAR), Gandhinagar, India
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16
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Gunjan S, Sharma T, Yadav K, Chauhan BS, Singh SK, Siddiqi MI, Tripathi R. Artemisinin Derivatives and Synthetic Trioxane Trigger Apoptotic Cell Death in Asexual Stages of Plasmodium. Front Cell Infect Microbiol 2018; 8:256. [PMID: 30094226 PMCID: PMC6070741 DOI: 10.3389/fcimb.2018.00256] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/04/2018] [Indexed: 11/13/2022] Open
Abstract
Although over the last 15 years, prevalence of malaria became reduced by over half but developing resistance against artemisinin derivatives and its combinations, which are only ray of hope to treat resistant malaria set back the control efforts and the key hinderence to achieve the goal of malaria elimination till 2030. In spite these artemisinins are precious antimalarials, their action mechanism is yet to be fully understood. Reactive oxygen species (ROS) produces by cleavage of endoperoxide bridge of artemisinin derivatives are known to be its antimalarial efficacy. Since ROS could induce apoptosis, here we had explored the effect of artemisinin derivatives on apoptotic machinery of malaria parasite, Plasmodium falciparum and its survival. We have studied the effect of a/β arteether, artesunate and a synthetic 1, 2, 4 trioxane on mitochondria, caspase activity and DNA during asexual blood stages of Plasmodium falciparum 3D7. Results have shown that cleavage of peroxide bridge of artemisinin derivatives and 1,2,4 trioxane generate reactive oxygen species which depolarize mitochondrial membrane potential and make it permeable which further followed by activation of caspase like enzyme and DNA fragmentation, which are hallmark of apoptotic cell death. These findings suggest that artemisinin derivatives and synthetic trioxane induce apoptosis like phenomena in erythrocytic stage of malaria parasite; Plasmodium falciparum.
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Affiliation(s)
- Sarika Gunjan
- Academy of Scientific and Innovative Research, New Delhi, India.,Division of Parasitology, Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow, India
| | - Tanuj Sharma
- Academy of Scientific and Innovative Research, New Delhi, India.,Division of Molecular & Structural Biology, Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow, India
| | - Kanchan Yadav
- Division of Parasitology, Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow, India
| | - Bhavana S Chauhan
- Academy of Scientific and Innovative Research, New Delhi, India.,Division of Parasitology, Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow, India
| | - Sunil K Singh
- Division of Parasitology, Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow, India
| | - Mohammad I Siddiqi
- Academy of Scientific and Innovative Research, New Delhi, India.,Division of Molecular & Structural Biology, Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow, India
| | - Renu Tripathi
- Academy of Scientific and Innovative Research, New Delhi, India.,Division of Parasitology, Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow, India
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17
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Reiling SJ, Krohne G, Friedrich O, Geary TG, Rohrbach P. Chloroquine exposure triggers distinct cellular responses in sensitive versus resistant Plasmodium falciparum parasites. Sci Rep 2018; 8:11137. [PMID: 30042399 PMCID: PMC6057915 DOI: 10.1038/s41598-018-29422-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/06/2018] [Indexed: 11/25/2022] Open
Abstract
Chloroquine (CQ) treatment failure in Plasmodium falciparum parasites has been documented for decades, but the pharmacological explanation of this phenotype is not fully understood. Current concepts attribute CQ resistance to reduced accumulation of the drug at a given external CQ concentration ([CQ]ex) in resistant compared to sensitive parasites. The implication of this explanation is that the mechanisms of CQ-induced toxicity in resistant and sensitive strains are similar once lethal internal concentrations have been reached. To test this hypothesis, we investigated the mechanism of CQ-induced toxicity in CQ-sensitive (CQS) versus CQ-resistant (CQR) parasites by analyzing the time-course of cellular responses in these strains after exposure to varying [CQ]ex as determined in 72 h toxicity assays. Parasite killing was delayed in CQR parasites for up to 10 h compared to CQS parasites when exposed to equipotent [CQ]ex. In striking contrast, brief exposure (1 h) to lethal [CQ]ex in CQS but not CQR parasites caused the appearance of hitherto undescribed hemozoin (Hz)-containing compartments in the parasite cytosol. Hz-containing compartments were very rarely observed in CQR parasites even after CQ exposures sufficient to cause irreversible cell death. These findings challenge current concepts that CQ killing of malaria parasites is solely concentration-dependent, and instead suggest that CQS and CQR strains fundamentally differ in the consequences of CQ exposure.
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Affiliation(s)
- Sarah J Reiling
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue (Montréal), Québec, Canada
| | - Georg Krohne
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Oliver Friedrich
- Institute of Medical Biotechnology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Timothy G Geary
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue (Montréal), Québec, Canada
| | - Petra Rohrbach
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue (Montréal), Québec, Canada.
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18
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Yan H, Bian A, Gao X, Li H, Chen Z, Liu X. Novel applications for an established antimalarial drug: tumoricidal activity of quinacrine. Future Oncol 2018; 14:1511-1520. [DOI: 10.2217/fon-2017-0728] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Quinacrine (QC), a synthetic antimalarial drug, was consistently used worldwide to combat malaria during the last century. Interestingly, later studies revealed that it also displays various additional properties, specifically antitumor activity. QC's antitumor activity occurs via a variety of pathways, including DNA intercalation, angiogenesis inhibition, signal transduction regulation, cell cycle arrest and autophagy induction. In combination with traditional therapies such as chemotherapy and radiotherapy, QC has also displayed synergistic effects against tumors, which may open promising therapeutic avenues. However, the breadth and complexity of its antitumor mechanisms have not yet been fully elucidated. In this review, we have systematically categorized QC's reported antitumor mechanisms from recent studies, to enable a deeper understanding of its antitumor activity.
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Affiliation(s)
- Hongru Yan
- Jiangsu Key Laboratory of Immunity & Metabolism, Department of Pathogenic Biology & Immunology, Xuzhou Medical University, Xuzhou, 221004, PR China
| | - Anning Bian
- Jiangsu Key Laboratory of Immunity & Metabolism, Department of Pathogenic Biology & Immunology, Xuzhou Medical University, Xuzhou, 221004, PR China
| | - Xiaoge Gao
- Cancer Institute, Xuzhou Medical University, Xuzhou, Jiangsu Province, 221002, PR China
| | - Huiqin Li
- Jiangsu Key Laboratory of Immunity & Metabolism, Department of Pathogenic Biology & Immunology, Xuzhou Medical University, Xuzhou, 221004, PR China
| | - Zetian Chen
- Jiangsu Key Laboratory of Immunity & Metabolism, Department of Pathogenic Biology & Immunology, Xuzhou Medical University, Xuzhou, 221004, PR China
| | - Xiangye Liu
- Jiangsu Key Laboratory of Immunity & Metabolism, Department of Pathogenic Biology & Immunology, Xuzhou Medical University, Xuzhou, 221004, PR China
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19
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High-Content Screening of the Medicines for Malaria Venture Pathogen Box for Plasmodium falciparum Digestive Vacuole-Disrupting Molecules Reveals Valuable Starting Points for Drug Discovery. Antimicrob Agents Chemother 2018; 62:AAC.02031-17. [PMID: 29311064 DOI: 10.1128/aac.02031-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 12/20/2017] [Indexed: 02/06/2023] Open
Abstract
Plasmodium falciparum infections leading to malaria have severe clinical manifestations and high mortality rates. Chloroquine (CQ), a former mainstay of malaria chemotherapy, has been rendered ineffective due to the emergence of widespread resistance. Recent studies, however, have unveiled a novel mode of action in which low-micromolar levels of CQ permeabilized the parasite's digestive vacuole (DV) membrane, leading to calcium efflux, mitochondrial depolarization, and DNA degradation. These phenotypes implicate the DV as an alternative target of CQ and suggest that DV disruption is an attractive target for exploitation by DV-disruptive antimalarials. In the current study, high-content screening of the Medicines for Malaria Venture (MMV) Pathogen Box (2015) was performed to select compounds which disrupt the DV membrane, as measured by the leakage of intravacuolar Ca2+ using the calcium probe Fluo-4 AM. The hits were further characterized by hemozoin biocrystallization inhibition assays and dose-response half-maximal (50%) inhibitory concentration (IC50) assays across resistant and sensitive strains. Three hits, MMV676380, MMV085071, and MMV687812, were shown to demonstrate a lack of CQ cross-resistance in parasite strains and field isolates. Through systematic analyses, MMV085071 emerged as the top hit due to its rapid parasiticidal effect, low-nanomolar IC50, and good efficacy in triggering DV disruption, mitochondrial degradation, and DNA fragmentation in P. falciparum These programmed cell death (PCD)-like phenotypes following permeabilization of the DV suggests that these compounds kill the parasite by a PCD-like mechanism. From the drug development perspective, MMV085071, which was identified to be a potent DV disruptor, offers a promising starting point for subsequent hit-to-lead generation and optimization through structure-activity relationships.
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20
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Chou ES, Abidi SZ, Teye M, Leliwa-Sytek A, Rask TS, Cobbold SA, Tonkin-Hill GQ, Subramaniam KS, Sexton AE, Creek DJ, Daily JP, Duffy MF, Day KP. A high parasite density environment induces transcriptional changes and cell death in Plasmodium falciparum blood stages. FEBS J 2018; 285:848-870. [PMID: 29281179 DOI: 10.1111/febs.14370] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 12/01/2017] [Accepted: 12/20/2017] [Indexed: 12/17/2022]
Abstract
Transient regulation of Plasmodium numbers below the density that induces fever has been observed in chronic malaria infections in humans. This species transcending control cannot be explained by immunity alone. Using an in vitro system we have observed density dependent regulation of malaria population size as a mechanism to possibly explain these in vivo observations. Specifically, Plasmodium falciparum blood stages from a high but not low-density environment exhibited unique phenotypic changes during the late trophozoite (LT) and schizont stages of the intraerythrocytic cycle. These included in order of appearance: failure of schizonts to mature and merozoites to replicate, apoptotic-like morphological changes including shrinking, loss of mitochondrial membrane potential, and blebbing with eventual release of aberrant parasites from infected erythrocytes. This unique death phenotype was triggered in a stage-specific manner by sensing of a high-density culture environment. Conditions of glucose starvation, nutrient depletion, and high lactate could not induce the phenotype. A high-density culture environment induced rapid global changes in the parasite transcriptome including differential expression of genes involved in cell remodeling, clonal antigenic variation, metabolism, and cell death pathways including an apoptosis-associated metacaspase gene. This transcriptional profile was also characterized by concomitant expression of asexual and sexual stage-specific genes. The data show strong evidence to support our hypothesis that density sensing exists in P. falciparum. They indicate that an apoptotic-like mechanism may play a role in P. falciparum density regulation, which, as in yeast, has features quite distinguishable from mammalian apoptosis. DATABASE Gene expression data are available in the GEO databases under the accession number GSE91188.
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Affiliation(s)
- Evelyn S Chou
- Bio21 Institute for Molecular Science and Biotechnology and School of BioSciences, University of Melbourne, Parkville, VIC., Australia
| | - Sabia Z Abidi
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Marian Teye
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, NY, USA
| | - Aleksandra Leliwa-Sytek
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, NY, USA
| | - Thomas S Rask
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, NY, USA
| | - Simon A Cobbold
- Bio21 Institute for Molecular Science and Biotechnology and School of BioSciences, University of Melbourne, Parkville, VIC., Australia
| | - Gerry Q Tonkin-Hill
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC., Australia
| | - Krishanthi S Subramaniam
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Anna E Sexton
- Drug Delivery Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC., Australia
| | - Darren J Creek
- Drug Delivery Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC., Australia
| | - Johanna P Daily
- Department of Medicine, Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Michael F Duffy
- Bio21 Institute for Molecular Science and Biotechnology and School of BioSciences, University of Melbourne, Parkville, VIC., Australia
| | - Karen P Day
- Bio21 Institute for Molecular Science and Biotechnology and School of BioSciences, University of Melbourne, Parkville, VIC., Australia
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21
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Deu E. Proteases as antimalarial targets: strategies for genetic, chemical, and therapeutic validation. FEBS J 2017; 284:2604-2628. [PMID: 28599096 PMCID: PMC5575534 DOI: 10.1111/febs.14130] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 04/29/2017] [Accepted: 06/06/2017] [Indexed: 01/17/2023]
Abstract
Malaria is a devastating parasitic disease affecting half of the world's population. The rapid emergence of resistance against new antimalarial drugs, including artemisinin-based therapies, has made the development of drugs with novel mechanisms of action extremely urgent. Proteases are enzymes proven to be well suited for target-based drug development due to our knowledge of their enzymatic mechanisms and active site structures. More importantly, Plasmodium proteases have been shown to be involved in a variety of pathways that are essential for parasite survival. However, pharmacological rather than target-based approaches have dominated the field of antimalarial drug development, in part due to the challenge of robustly validating Plasmodium targets at the genetic level. Fortunately, over the last few years there has been significant progress in the development of efficient genetic methods to modify the parasite, including several conditional approaches. This progress is finally allowing us not only to validate essential genes genetically, but also to study their molecular functions. In this review, I present our current understanding of the biological role proteases play in the malaria parasite life cycle. I also discuss how the recent advances in Plasmodium genetics, the improvement of protease-oriented chemical biology approaches, and the development of malaria-focused pharmacological assays, can be combined to achieve a robust biological, chemical and therapeutic validation of Plasmodium proteases as viable drug targets.
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Affiliation(s)
- Edgar Deu
- Chemical Biology Approaches to Malaria LaboratoryThe Francis Crick InstituteLondonUK
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Jida M, Sanchez CP, Urgin K, Ehrhardt K, Mounien S, Geyer A, Elhabiri M, Lanzer M, Davioud-Charvet E. A Redox-Active Fluorescent pH Indicator for Detecting Plasmodium falciparum Strains with Reduced Responsiveness to Quinoline Antimalarial Drugs. ACS Infect Dis 2017; 3:119-131. [PMID: 28183182 DOI: 10.1021/acsinfecdis.5b00141] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mutational changes in the Plasmodium falciparum chloroquine resistance transporter (PfCRT) have been associated with differential responses to a wide spectrum of biologically active compounds including current and former quinoline and quinoline-like antimalarial drugs. PfCRT confers altered drug responsiveness by acting as a transport system, expelling drugs from the parasite's digestive vacuole where these drugs exert, at least part of, their antiplasmodial activity. To preserve the efficacy of these invaluable drugs, novel functional tools are required for epidemiological surveys of parasite strains carrying mutant PfCRT variants and for drug development programs aimed at inhibiting or circumventing the action of PfCRT. Here we report the synthesis and characterization of a pH-sensitive fluorescent chloroquine analogue consisting of 7-chloro-N-{2-[(propan-2-yl)amino]ethyl}quinolin-4-amine functionalized with the fluorochrome 7-nitrobenzofurazan (NBD) (henceforth termed Fluo-CQ). In the parasite, Fluo-CQ accumulates in the digestive vacuole, giving rise to a strong fluorescence signal but only in parasites carrying the wild type PfCRT. In parasites carrying the mutant PfCRT, Fluo-CQ does not accumulate. The differential handling of the fluorescent probe, combined with live cell imaging, provides a diagnostic tool for quick detection of those P. falciparum strains that carry a PfCRT variant associated with altered responsiveness to quinoline and quinoline-like antimalarial drugs. In contrast to the accumulation studies, chloroquine (CQ)-resistant parasites were observed cross-resistant to Fluo-CQ when the chemical probe was tested in various CQ-sensitive and -resistant parasite strains. NBD derivatives were found to act as redox cyclers of two essential targets, using a coupled assay based on methemoglobin and the NADPH-dependent glutathione reductase (GRs) from P. falciparum. This redox activity is proposed to contribute to the dual action of Fluo-CQ on redox equilibrium and methemoglobin reduction via PfCRT-mediated drug efflux in the cytosol and then continuous redox-dependent shuttling between food vacuole and cytosol. Taking into account these physicochemical characteristics, a model was proposed to explain Fluo-CQ antimalarial effects involving the contribution of PfCRT-mediated transport, methemoglobin reduction, hematin binding, and NBD reduction activity catalyzed by PfGR in CQ-resistant versus CQ-sensitive parasites. Therefore, introduction of NBD fluorophore in drugs is not inert and should be taken into account in drug transport and imaging studies.
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Affiliation(s)
- Mouhamad Jida
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), 25 rue Becquerel, F-67087 Strasbourg, France
| | - Cecilia P. Sanchez
- Zentrum
für Infektiologie, Parasitologie, Universität Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Karène Urgin
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), 25 rue Becquerel, F-67087 Strasbourg, France
| | - Katharina Ehrhardt
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), 25 rue Becquerel, F-67087 Strasbourg, France
- Zentrum
für Infektiologie, Parasitologie, Universität Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Saravanan Mounien
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), 25 rue Becquerel, F-67087 Strasbourg, France
| | - Aurelia Geyer
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), 25 rue Becquerel, F-67087 Strasbourg, France
| | - Mourad Elhabiri
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), 25 rue Becquerel, F-67087 Strasbourg, France
| | - Michael Lanzer
- Zentrum
für Infektiologie, Parasitologie, Universität Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Elisabeth Davioud-Charvet
- UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, European School of Chemistry, Polymers and Materials (ECPM), 25 rue Becquerel, F-67087 Strasbourg, France
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23
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Asahi H, Kobayashi F, Inoue SI, Niikura M, Yagita K, Tolba MEM. Copper Homeostasis for the Developmental Progression of Intraerythrocytic Malarial Parasite. Curr Top Med Chem 2017; 16:3048-3057. [PMID: 26881705 PMCID: PMC5068492 DOI: 10.2174/1568026616999160215151704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/10/2016] [Accepted: 02/20/2016] [Indexed: 01/22/2023]
Abstract
Malaria is one of the world’s most devastating diseases, particularly in the tropics. In humans, Plasmodium falciparum lives mainly within red blood cells, and malaria pathogenesis depends on the red blood cells being infected with the parasite. Non-esterified fatty acids (NEFAs), including cis-9-octadecenoic acid, and phospholipids have been critical for complete parasite growth in serum-free culture, although the efficacy of NEFAs in sustaining the growth of P. falciparum has varied markedly. Hexadecanoic acid and trans-9-octadecenoic acid have arrested development of the parasite, in association with down-regulation of genes encoding copper-binding proteins. Selective removal of Cu+ ions has blockaded completely the ring–trophozoite–schizont progression of the parasite. The importance of copper homeostasis for the developmental progression of P. falciparum has been confirmed by inhibition of copper-binding proteins that regulate copper physiology and function by associating with copper ions. These data have provided strong evidence for a link between healthy copper homeostasis and successive developmental progression of P. falciparum. Perturbation of copper homeostasis may be, thus, instrumental in drug and vaccine development for the malaria medication. We review the importance of copper homeostasis in the asexual growth of P. falciparum in relation to NEFAs, copper-binding proteins, apoptosis, mitochondria, and gene expression.
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Affiliation(s)
- Hiroko Asahi
- Division of Tropical Diseases and Parasitology, Department of Infectious Diseases, Kyorin University School of Medicine, Tokyo 181 8611, Japan.
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24
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Plasmodium falciparum exhibits markers of regulated cell death at high population density in vitro. Parasitol Int 2016; 65:715-727. [DOI: 10.1016/j.parint.2016.07.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 07/13/2016] [Accepted: 07/14/2016] [Indexed: 11/22/2022]
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Chia WN, Lee YQ, Tan KSW. Imaging flow cytometry for the screening of compounds that disrupt the Plasmodium falciparum digestive vacuole. Methods 2016; 112:211-220. [PMID: 27389304 DOI: 10.1016/j.ymeth.2016.07.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/16/2016] [Accepted: 07/03/2016] [Indexed: 10/21/2022] Open
Abstract
Malaria, despite being one of the world's oldest infectious diseases, remains difficult to eradicate because the parasite is rapidly developing resistance to frontline chemotherapies. Previous studies have shown that the parasite exhibits features resembling programmed cell death upon treatment with drugs that disrupt its digestive vacuole (DV), providing a phenotypic readout that can be detected using the imaging flow cytometer. Large compound collections can thus be screened to identify drugs that are able to disrupt the DV of the malaria parasite using this high-content high-throughput screening platform. As a proof-of-concept, 4440 compounds were screened using this platform in 4months and 254 hits (5.7% hit rate) were obtained. Additionally, 25 compounds (0.6% top hit rate) were observed to retain potent DV disruption activity that was comparable to the canonical DV disruptive drug chloroquine when tested at a ten-fold lower concentration from the original screen. This pilot study demonstrates the robustness and high-throughput capability of the imaging flow cytometer and we report herein the methodology of this screening assay.
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Affiliation(s)
- Wan Ni Chia
- Department of Microbiology and Immunology, National University of Singapore, Singapore
| | - Yan Quan Lee
- Department of Microbiology and Immunology, National University of Singapore, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore
| | - Kevin Shyong-Wei Tan
- Department of Microbiology and Immunology, National University of Singapore, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore.
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26
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Mefloquine induces ROS mediated programmed cell death in malaria parasite: Plasmodium. Apoptosis 2016; 21:955-64. [DOI: 10.1007/s10495-016-1265-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Screening for Drugs Against the Plasmodium falciparum Digestive Vacuole by Imaging Flow Cytometry. Methods Mol Biol 2016; 1389:195-205. [PMID: 27460247 DOI: 10.1007/978-1-4939-3302-0_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Phenotypic assays are increasingly employed to provide clues about drug mechanisms. In antimalarial drug screening, however, the majority of assays are designed to only measure parasite-killing activity. We describe here a high-content assay to detect drug-mediated perturbation of the digestive vacuole integrity in the trophozoite stage of Plasmodium falciparum, using the ImageStream imaging flow cytometer.
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28
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Siwo GH, Smith RS, Tan A, Button-Simons KA, Checkley LA, Ferdig MT. An integrative analysis of small molecule transcriptional responses in the human malaria parasite Plasmodium falciparum. BMC Genomics 2015; 16:1030. [PMID: 26637195 PMCID: PMC4670519 DOI: 10.1186/s12864-015-2165-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 10/29/2015] [Indexed: 12/05/2022] Open
Abstract
Background Transcriptional responses to small molecules can provide insights into drug mode of action (MOA). The capacity of the human malaria parasite, Plasmodium falciparum, to respond specifically to transcriptional perturbations has been unclear based on past approaches. Here, we present the most extensive profiling to date of the parasite’s transcriptional responsiveness to thirty-one chemically and functionally diverse small molecules. Methods We exposed two laboratory strains of the human malaria parasite P. falciparum to brief treatments of thirty-one chemically and functionally diverse small molecules associated with biological effects across multiple pathways based on various levels of evidence. We investigated the impact of chemical composition and MOA on gene expression similarities that arise between perturbations by various compounds. To determine the target biological pathways for each small molecule, we developed a novel framework for encoding small molecule effects on a spectra of biological processes or GO functions that are enriched in the differentially expressed genes of a given small molecule perturbation. Results We find that small molecules associated with similar transcriptional responses contain similar chemical features, and/ or have a shared MOA. The approach also revealed complex relationships between drugs and biological pathways that are missed by most exisiting approaches. For example, the approach was able to partition small molecule responses into drug-specific effects versus non-specific effects. Conclusions Our work provides a new framework for linking transcriptional responses to drug MOA in P. falciparum and can be generalized for the same purpose in other organisms. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-2165-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Geoffrey H Siwo
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.,Current Address: IBM TJ Watson Research Center, Yorktown Heights, NY, 10598, USA.,Current Address: IBM Research-Africa, South Africa Lab, Sandton, Johannesburg, 2196, South Africa
| | - Roger S Smith
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.,Current Address: Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Asako Tan
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.,Epicenter, Madison, WI, 53719, USA
| | - Katrina A Button-Simons
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Lisa A Checkley
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Michael T Ferdig
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, USA.
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Engelbrecht D, Coetzer TL. Sunlight inhibits growth and induces markers of programmed cell death in Plasmodium falciparum in vitro. Malar J 2015; 14:378. [PMID: 26419629 PMCID: PMC4588498 DOI: 10.1186/s12936-015-0867-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 08/22/2015] [Indexed: 12/20/2022] Open
Abstract
Background Plasmodium falciparum is responsible for the majority of global malaria deaths. During the pathogenic blood stages of infection, a rapid increase in parasitaemia threatens the survival of the host before transmission of slow-maturing sexual parasites to the mosquito vector to continue the life cycle. Programmed cell death (PCD) may provide the parasite with the means to control its burden on the host and thereby ensure its own survival. Various environmental stress factors encountered during malaria may induce PCD in P. falciparum. This study is the first to characterize parasite cell death in response to natural sunlight. Methods The 3D7 strain of P. falciparum was cultured in vitro in donor erythrocytes. Synchronized and mixed-stage parasitized cultures were exposed to sunlight for 1 h and compared to cultures maintained in the dark, 24 h later. Mixed-stage parasites were also subjected to a second one-hour exposure at 24 h and assessed at 48 h. Parasitaemia was measured daily by flow cytometry. Biochemical markers of cell death were assessed, including DNA fragmentation, mitochondrial membrane polarization and phosphatidylserine externalization. Results Sunlight inhibited P. falciparum growth in vitro. Late-stage parasites were more severely affected than early stages. However, some late-stage parasites survived exposure to sunlight to form new rings 24 h later, as would be expected during PCD whereby only a portion of the population dies. DNA fragmentation was observed at 24 and 48 h and preceded mitochondrial hyperpolarization in mixed-stage parasites at 48 h. Mitochondrial hyperpolarization likely resulted from increased oxidative stress. Although data suggested increased phosphatidylserine externalization in mixed-stage parasites, results were not statistically significant. Conclusion The combination of biochemical markers and the survival of some parasites, despite exposure to a lethal stimulus, support the occurrence of PCD in P. falciparum.
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Affiliation(s)
- Dewaldt Engelbrecht
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, Wits Medical School, Wits Research Institute for Malaria, University of the Witwatersrand, 7th floor, 7 York Road, Parktown, Johannesburg, 2193, South Africa.
| | - Thérèsa Louise Coetzer
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, Wits Medical School, Wits Research Institute for Malaria, University of the Witwatersrand, 7th floor, 7 York Road, Parktown, Johannesburg, 2193, South Africa. .,National Health Laboratory Service, Johannesburg, South Africa.
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Abstract
Lysosomes play important roles in autophagy, not only in autophagosome degradation, but also in autophagy initiation. In Trypanosoma brucei, an early divergent protozoan parasite, we discovered a previously unappreciated function of the acidocalcisome, a lysosome-related organelle characterized by acidic pH and large content of Ca(2+) and polyphosphates, in autophagy regulation. Starvation- and chemical-induced autophagy is accompanied with acidocalcisome acidification, and blocking the acidification completely inhibits autophagosome formation. Blocking acidocalcisome biogenesis by depleting the adaptor protein-3 complex, which does not affect lysosome biogenesis or function, also inhibits autophagy. Overall, our results support the role of the acidocalcisome, a conserved organelle from bacteria to human, as a relevant regulator in autophagy.
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Key Words
- AO, acridine orange
- AP-3, adaptor protein-3
- ATG, autophagy-related
- BODIPY-CQ, BODIPY-chloroquine
- BafA1, bafilomycin A1
- CQ, chloroquine
- DAPI, 4′, 6-diamidino-2-phenylindole
- MTORC1, mechanistic target of rapamycin complex 1
- PPi, pyrophosphate
- PtdIns3K, phosphatidylinositol 3-kinase
- PtdIns3P, phosphatidylinositol 3-phosphate
- RNAi, RNA interference
- T. brucei, Trypanosoma brucei
- TOR, target of rapamycin
- TbVMA1, the subunit A of V-H+-ATPase in Trypanosoma brucei
- TbVP1, vacuolar pyrophosphatase in Trypanosoma brucei
- TbVPH1, the α, subunit of V-H+-ATPase in Trypanosoma brucei
- Tbβ3, the β3 subunit of adaptor protein-3 complex in Trypanosoma brucei
- Tbδ, the δ, subunit of adaptor protein-3 complex in Trypanosoma brucei
- Trypanosoma brucei
- V-H+-ATPase, vacuolar-type H+-ATPase
- V-PPase, vacuolar pyrophophatase
- acidity
- acidocalcisome
- autophagy
- coumarin-CQ, coumarin-chloroquine
- lysosome-related organelle
- polyP, polyphosphate
- protozoan parasite
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Affiliation(s)
- Feng-Jun Li
- a Department of Biological Sciences ; National University of Singapore ; Singapore
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Abstract
Mechanisms of cell death in unicellular parasites have been subjects of debate for the last decade, with studies demonstrating evidence of apoptosis or non-apoptosis like mechanisms, including necrosis, and autophagy. Recent clarifications on the definition of regulated or accidental cell death by The Nomenclature Committee on Cell Death provides an opportunity to reanalyze some data, re-evaluate conclusions in the light of parasite diversity, and to propose alternative arguments in the context of malaria drug resistance, considering lack of really new drugs in the pipeline. Deciphering the mechanisms of death may help in detection of new drug targets and the design of innovative drugs. However, classifications have been evolving rapidly since initial description of "programmed cell death", leading to some uncertainty as to whether Plasmodium cell death is accidental or regulated.
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Affiliation(s)
- Fatimata Sow
- University Claude Bernard Lyon 1, Malaria Research Unit, SMITh, ICBMS, UMR 5246 CNRS-INSA-CPE-UCBL1, 8 avenue Rockefeller, 69373 Lyon cedex 08, France
| | - Mary Nyonda
- University Claude Bernard Lyon 1, Malaria Research Unit, SMITh, ICBMS, UMR 5246 CNRS-INSA-CPE-UCBL1, 8 avenue Rockefeller, 69373 Lyon cedex 08, France
| | - Anne-Lise Bienvenu
- University Claude Bernard Lyon 1, Malaria Research Unit, SMITh, ICBMS, UMR 5246 CNRS-INSA-CPE-UCBL1, 8 avenue Rockefeller, 69373 Lyon cedex 08, France. ; Hospices Civils de Lyon, Institut de Parasitologie et de Mycologie Médicale (IP2M), Hôpital de la Croix-Rousse, 103 grande rue de la Croix-Rousse, 69317 Lyon cedex 04, France
| | - Stephane Picot
- University Claude Bernard Lyon 1, Malaria Research Unit, SMITh, ICBMS, UMR 5246 CNRS-INSA-CPE-UCBL1, 8 avenue Rockefeller, 69373 Lyon cedex 08, France. ; Hospices Civils de Lyon, Institut de Parasitologie et de Mycologie Médicale (IP2M), Hôpital de la Croix-Rousse, 103 grande rue de la Croix-Rousse, 69317 Lyon cedex 04, France
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Disruption of cellular homeostasis induces organelle stress and triggers apoptosis like cell-death pathways in malaria parasite. Cell Death Dis 2015; 6:e1803. [PMID: 26136076 PMCID: PMC4650714 DOI: 10.1038/cddis.2015.142] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 04/06/2015] [Accepted: 04/07/2015] [Indexed: 01/29/2023]
Abstract
A regulated protein turnover machinery in the cell is essential for effective cellular homeostasis; any interference with this system induces cellular stress and alters the normal functioning of proteins important for cell survival. In this study, we show that persistent cellular stress and organelle dysfunction because of disruption of cellular homeostasis in human malaria parasite Plasmodium falciparum, leads to apoptosis-like cell death. Quantitative global proteomic analysis of the stressed parasites before onset of cell death, showed upregulation of a number of proteins involved in cellular homeostasis; protein network analyses identified upregulated metabolic pathways that may be associated with stress tolerance and pro-survival mechanism. However, persistent stress on parasites cause structural abnormalities in endoplasmic reticulum and mitochondria, subsequently a cascade of reactions are initiated in parasites including rise in cytosolic calcium levels, loss of mitochondrial membrane potential and activation of VAD-FMK-binding proteases. We further show that activation of VAD-FMK-binding proteases in the parasites leads to degradation of phylogenetically conserved protein, TSN (Tudor staphylococcal nuclease), a known target of metacaspases, as well as degradation of other components of spliceosomal complex. Loss of spliceosomal machinery impairs the mRNA splicing, leading to accumulation of unprocessed RNAs in the parasite and thus dysregulate vital cellular functions, which in turn leads to execution of apoptosis-like cell death. Our results establish one of the possible mechanisms of instigation of cell death by organelle stress in Plasmodium.
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Zhang R, Suwanarusk R, Malleret B, Cooke BM, Nosten F, Lau YL, Dao M, Lim CT, Renia L, Tan KSW, Russell B. A Basis for Rapid Clearance of Circulating Ring-Stage Malaria Parasites by the Spiroindolone KAE609. J Infect Dis 2015; 213:100-4. [PMID: 26136472 PMCID: PMC4676544 DOI: 10.1093/infdis/jiv358] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 06/21/2015] [Indexed: 11/30/2022] Open
Abstract
Recent clinical trials revealed a surprisingly rapid clearance of red blood cells (RBCs) infected with malaria parasites by the spiroindolone KAE609. Here, we show that ring-stage parasite–infected RBCs exposed to KAE609 become spherical and rigid, probably through osmotic dysregulation consequent to the disruption of the parasite's sodium efflux pump (adenosine triphosphate 4). We also show that this peculiar drug effect is likely to cause accelerated splenic clearance of the rheologically impaired Plasmodium vivax– and Plasmodium falciparum–infected RBCs.
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Affiliation(s)
- Rou Zhang
- Department of Microbiology, Yong Loo Lin School of Medicine
| | - Rossarin Suwanarusk
- Singapore Immunology Network (SIgN), Agency for Science Technology and Research (A*STAR), Biopolis
| | - Benoit Malleret
- Department of Microbiology, Yong Loo Lin School of Medicine Singapore Immunology Network (SIgN), Agency for Science Technology and Research (A*STAR), Biopolis
| | - Brian M Cooke
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Francois Nosten
- Shoklo Malaria Research Unit, Mae Sot, Tak Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, United Kingdom
| | - Yee-Ling Lau
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur
| | - Ming Dao
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge
| | - Chwee Teck Lim
- Biomedical Engineering, National University of Singapore
| | - Laurent Renia
- Singapore Immunology Network (SIgN), Agency for Science Technology and Research (A*STAR), Biopolis
| | | | - Bruce Russell
- Department of Microbiology, Yong Loo Lin School of Medicine
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Characterization of the commercially-available fluorescent chloroquine-BODIPY conjugate, LynxTag-CQGREEN, as a marker for chloroquine resistance and uptake in a 96-well plate assay. PLoS One 2014; 9:e110800. [PMID: 25343249 PMCID: PMC4208776 DOI: 10.1371/journal.pone.0110800] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 09/18/2014] [Indexed: 11/24/2022] Open
Abstract
Chloroquine was a cheap, extremely effective drug against Plasmodium falciparum until resistance arose. One approach to reversing resistance is the inhibition of chloroquine efflux from its site of action, the parasite digestive vacuole. Chloroquine accumulation studies have traditionally relied on radiolabelled chloroquine, which poses several challenges. There is a need for development of a safe and biologically relevant substitute. We report here a commercially-available green fluorescent chloroquine-BODIPY conjugate, LynxTag-CQGREEN, as a proxy for chloroquine accumulation. This compound localized to the digestive vacuole of the parasite as observed under confocal microscopy, and inhibited growth of chloroquine-sensitive strain 3D7 more extensively than in the resistant strains 7G8 and K1. Microplate reader measurements indicated suppression of LynxTag-CQGREEN efflux after pretreatment of parasites with known reversal agents. Microsomes carrying either sensitive- or resistant-type PfCRT were assayed for uptake; resistant-type PfCRT exhibited increased accumulation of LynxTag-CQGREEN, which was suppressed by pretreatment with known chemosensitizers. Eight laboratory strains and twelve clinical isolates were sequenced for PfCRT and Pgh1 haplotypes previously reported to contribute to drug resistance, and pfmdr1 copy number and chloroquine IC50s were determined. These data were compared with LynxTag-CQGREEN uptake/fluorescence by multiple linear regression to identify genetic correlates of uptake. Uptake of the compound correlated with the logIC50 of chloroquine and, more weakly, a mutation in Pgh1, F1226Y.
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Ch'ng JH, Lee YQ, Gun SY, Chia WN, Chang ZW, Wong LK, Batty KT, Russell B, Nosten F, Renia L, Tan KSW. Validation of a chloroquine-induced cell death mechanism for clinical use against malaria. Cell Death Dis 2014; 5:e1305. [PMID: 24967967 PMCID: PMC4611737 DOI: 10.1038/cddis.2014.265] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 04/04/2014] [Accepted: 05/20/2014] [Indexed: 01/09/2023]
Abstract
An alternative antimalarial pathway of an ‘outdated' drug, chloroquine (CQ), may facilitate its return to the shrinking list of effective antimalarials. Conventionally, CQ is believed to interfere with hemozoin formation at nanomolar concentrations, but resistant parasites are able to efflux this drug from the digestive vacuole (DV). However, we show that the DV membrane of both resistant and sensitive laboratory and field parasites is compromised after exposure to micromolar concentrations of CQ, leading to an extrusion of DV proteases. Furthermore, only a short period of exposure is required to compromise the viability of late-stage parasites. To study the feasibility of this strategy, mice malaria models were used to demonstrate that high doses of CQ also triggered DV permeabilization in vivo and reduced reinvasion efficiency. We suggest that a time-release oral formulation of CQ may sustain elevated blood CQ levels sufficiently to clear even CQ-resistant parasites.
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Affiliation(s)
- J-H Ch'ng
- 1] Department of Microbiology, National University of Singapore, 5 Science Drive 2, Singapore, Singapore [2] Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Nobels väg 16, KI Solna Campus, Box 280, Stockholm, Sweden
| | - Y-Q Lee
- 1] Department of Microbiology, National University of Singapore, 5 Science Drive 2, Singapore, Singapore [2] NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Centre for Life Sciences (CeLS), #05-01, 28 Medical Drive, Singapore, Singapore
| | - S Y Gun
- Singapore Immunology Network, Agency for Science Technology and Research (A*STAR), Biopolis, 8A Biomedical Grove, Immunos Building, Level 4, Singapore, Singapore
| | - W-N Chia
- Singapore Immunology Network, Agency for Science Technology and Research (A*STAR), Biopolis, 8A Biomedical Grove, Immunos Building, Level 4, Singapore, Singapore
| | - Z-W Chang
- Singapore Immunology Network, Agency for Science Technology and Research (A*STAR), Biopolis, 8A Biomedical Grove, Immunos Building, Level 4, Singapore, Singapore
| | - L-K Wong
- Department of Chemistry, National University of Singapore, Block S8, Level 3, 3 Science Drive 3, Singapore, Singapore
| | - K T Batty
- 1] School of Pharmacy, Curtin University, GPO Box U1987, Perth Western Australia 6845 Bentley, WA, Australia [2] West Coast Institute, 35 Kendrew Crescent, Joondalup, WA, Australia
| | - B Russell
- Department of Microbiology, National University of Singapore, 5 Science Drive 2, Singapore, Singapore
| | - F Nosten
- 1] Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 68/30 Bantung Road, PO.BOX 46, Maesot, TAK, Thailand [2] Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Churchill Hospital, Old Road, Oxford, UK
| | - L Renia
- Singapore Immunology Network, Agency for Science Technology and Research (A*STAR), Biopolis, 8A Biomedical Grove, Immunos Building, Level 4, Singapore, Singapore
| | - K S-W Tan
- Department of Microbiology, National University of Singapore, 5 Science Drive 2, Singapore, Singapore
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Cheema HS, Prakash O, Pal A, Khan F, Bawankule DU, Darokar MP. Glabridin induces oxidative stress mediated apoptosis like cell death of malaria parasite Plasmodium falciparum. Parasitol Int 2014; 63:349-58. [DOI: 10.1016/j.parint.2013.12.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 11/12/2013] [Accepted: 12/10/2013] [Indexed: 01/14/2023]
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Kotturi SR, Somanadhan B, Ch’ng JH, Tan KSW, Butler MS, Lear MJ. Diverted total synthesis of falcitidin acyl tetrapeptides as new antimalarial leads. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.02.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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A whole cell pathway screen reveals seven novel chemosensitizers to combat chloroquine resistant malaria. Sci Rep 2014; 3:1734. [PMID: 23615863 PMCID: PMC3635055 DOI: 10.1038/srep01734] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 04/11/2013] [Indexed: 11/09/2022] Open
Abstract
Due to the widespread prevalence of resistant parasites, chloroquine (CQ) was removed from front-line antimalarial chemotherapy in the 1990s despite its initial promise of disease eradication. Since then, resistance-conferring mutations have been identified in transporters such as the PfCRT, that allow for the efflux of CQ from its primary site of action, the parasite digestive vacuole. Chemosensitizing/chemoreversing compounds interfere with the function of these transporters thereby sensitizing parasites to CQ once again. However, compounds identified thus far have disappointing in vivo efficacy and screening for alternative candidates is required to revive this strategy. In this study, we propose a simple and direct means to rapidly screen for such compounds using a fluorescent-tagged CQ molecule. When this screen was applied to a small library, seven novel chemosensitizers (octoclothepin, methiothepin, metergoline, loperamide, chlorprothixene, L-703,606 and mibefradil) were quickly elucidated, including two which showed greater potency than the classical chemosensitizers verapamil and desipramine.
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Shapiro HM, Apte SH, Chojnowski GM, Hänscheid T, Rebelo M, Grimberg BT. Cytometry in malaria--a practical replacement for microscopy? ACTA ACUST UNITED AC 2014; Chapter 11:11.20.1-11.20.23. [PMID: 23835802 DOI: 10.1002/0471142956.cy1120s65] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Malaria, caused by protozoan Plasmodium parasites, kills ~800,000 people each year. Exact figures are uncertain because presumptive diagnoses are often made without identifying parasites in patients' blood either by microscopy, using Giemsa's century-old stain, or by simpler tests that are ultimately dependent on microscopy for quality control. Microscopy itself relies on trained observers' ability to detect subtle morphological features of parasitized red blood cells, only a few of which may be present on a slide. Quantitative and objective flow cytometric measurements of cellular constituents such as DNA, RNA, and the malaria pigment hemozoin are now useful in research in malaria biology and pharmacology, and can provide more reliable identification of parasite species and developmental stages and better detection of low-density parasitemia than could microscopy. The same measurements can now be implemented in much smaller, simpler, cheaper imaging cytometers, potentially providing a more accurate and precise diagnostic modality.
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A process similar to autophagy is associated with cytocidal chloroquine resistance in Plasmodium falciparum. PLoS One 2013; 8:e79059. [PMID: 24278114 PMCID: PMC3835802 DOI: 10.1371/journal.pone.0079059] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 09/24/2013] [Indexed: 12/31/2022] Open
Abstract
Resistance to the cytostatic activity of the antimalarial drug chloroquine (CQ) is becoming well understood, however, resistance to cytocidal effects of CQ is largely unexplored. We find that PfCRT mutations that almost fully recapitulate P. falciparum cytostatic CQ resistance (CQRCS) as quantified by CQ IC50 shift, account for only 10–20% of cytocidal CQR (CQRCC) as quantified by CQ LD50 shift. Quantitative trait loci (QTL) analysis of the progeny of a chloroquine sensitive (CQS; strain HB3)×chloroquine resistant (CQR; strain Dd2) genetic cross identifies distinct genetic architectures for CQRCS vs CQRCC phenotypes, including identification of novel interacting chromosomal loci that influence CQ LD50. Candidate genes in these loci are consistent with a role for autophagy in CQRCC, leading us to directly examine the autophagy pathway in intraerythrocytic CQR parasites. Indirect immunofluorescence of RBC infected with synchronized CQS vs CQR trophozoite stage parasites reveals differences in the distribution of the autophagy marker protein PfATG8 coinciding with CQRCC. Taken together, the data show that an unusual autophagy – like process is either activated or inhibited for intraerythrocytic trophozoite parasites at LD50 doses (but not IC50 doses) of CQ, that the pathway is altered in CQR P. falciparum, and that it may contribute along with mutations in PfCRT to confer the CQRCC phenotype.
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41
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A high-content phenotypic screen reveals the disruptive potency of quinacrine and 3',4'-dichlorobenzamil on the digestive vacuole of Plasmodium falciparum. Antimicrob Agents Chemother 2013; 58:550-8. [PMID: 24217693 DOI: 10.1128/aac.01441-13] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Plasmodium falciparum is the etiological agent of malignant malaria and has been shown to exhibit features resembling programmed cell death. This is triggered upon treatment with low micromolar doses of chloroquine or other lysosomotrophic compounds and is associated with leakage of the digestive vacuole contents. In order to exploit this cell death pathway, we developed a high-content screening method to select compounds that can disrupt the parasite vacuole, as measured by the leakage of intravacuolar Ca(2+). This assay uses the ImageStream 100, an imaging-capable flow cytometer, to assess the distribution of the fluorescent calcium probe Fluo-4. We obtained two hits from a small library of 25 test compounds, quinacrine and 3',4'-dichlorobenzamil. The ability of these compounds to permeabilize the digestive vacuole in laboratory strains and clinical isolates was validated by confocal microscopy. The hits could induce programmed cell death features in both chloroquine-sensitive and -resistant laboratory strains. Quinacrine was effective at inhibiting field isolates in a 48-h reinvasion assay regardless of artemisinin clearance status. We therefore present as proof of concept a phenotypic screening method with the potential to provide mechanistic insights to the activity of antimalarial drugs.
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Abstract
Lysosomes serve as the cellular recycling centre and are filled with numerous hydrolases that can degrade most cellular macromolecules. Lysosomal membrane permeabilization and the consequent leakage of the lysosomal content into the cytosol leads to so-called "lysosomal cell death". This form of cell death is mainly carried out by the lysosomal cathepsin proteases and can have necrotic, apoptotic or apoptosis-like features depending on the extent of the leakage and the cellular context. This article summarizes our current knowledge on lysosomal cell death with an emphasis on the upstream mechanisms that lead to lysosomal membrane permeabilization.
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Affiliation(s)
- Sonja Aits
- Danish Cancer Society Research Center, Cell Death and Metabolism, Strandboulevarden 49, DK-2100 Copenhagen, Denmark
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43
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Taylor-Brown E, Hurd H. The first suicides: a legacy inherited by parasitic protozoans from prokaryote ancestors. Parasit Vectors 2013; 6:108. [PMID: 23597031 PMCID: PMC3640913 DOI: 10.1186/1756-3305-6-108] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 04/05/2013] [Indexed: 12/23/2022] Open
Abstract
It is more than 25 years since the first report that a protozoan parasite could die by a process resulting in a morphological phenotype akin to apoptosis. Since then these phenotypes have been observed in many unicellular parasites, including trypanosomatids and apicomplexans, and experimental evidence concerning the molecular pathways that are involved is growing. These observations support the view that this form of programmed cell death is an ancient one that predates the evolution of multicellularity. Here we review various hypotheses that attempt to explain the origin of apoptosis, and look for support for these hypotheses amongst the parasitic protists as, with the exception of yeast, most of the work on death mechanisms in unicellular organisms has focussed on them. We examine the role that addiction modules may have played in the original eukaryote cell and the part played by mitochondria in the execution of present day cells, looking for examples from Leishmania spp. Trypanosoma spp. and Plasmodium spp. In addition, the expanding knowledge of proteases, nucleases and other molecules acting in protist execution pathways has enabled comparisons to be made with extant Archaea and bacteria and with biochemical pathways that evolved in metazoans. These comparisons lend support to the original sin hypothesis but also suggest that present-day death pathways may have had multifaceted beginnings.
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Eickel N, Kaiser G, Prado M, Burda PC, Roelli M, Stanway RR, Heussler VT. Features of autophagic cell death in Plasmodium liver-stage parasites. Autophagy 2013; 9:568-80. [PMID: 23388496 DOI: 10.4161/auto.23689] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Analyzing molecular determinants of Plasmodium parasite cell death is a promising approach for exploring new avenues in the fight against malaria. Three major forms of cell death (apoptosis, necrosis and autophagic cell death) have been described in multicellular organisms but which cell death processes exist in protozoa is still a matter of debate. Here we suggest that all three types of cell death occur in Plasmodium liver-stage parasites. Whereas typical molecular markers for apoptosis and necrosis have not been found in the genome of Plasmodium parasites, we identified genes coding for putative autophagy-marker proteins and thus concentrated on autophagic cell death. We characterized the Plasmodium berghei homolog of the prominent autophagy marker protein Atg8/LC3 and found that it localized to the apicoplast. A relocalization of PbAtg8 to autophagosome-like vesicles or vacuoles that appear in dying parasites was not, however, observed. This strongly suggests that the function of this protein in liver-stage parasites is restricted to apicoplast biology.
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Affiliation(s)
- Nina Eickel
- Institute of Cell Biology, University of Bern, Bern, Switzerland
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Chen WJ, Huang CG, Fan-Chiang MH, Liu YH, Lee YF. Apoptosis of Ascogregarina taiwanensis (Apicomplexa: Lecudinidae), which failed to migrate within its natural host. J Exp Biol 2013; 216:230-5. [PMID: 22996442 DOI: 10.1242/jeb.072918] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Sexual reproduction of Ascogregarina taiwanensis (Apicomplexa: Lecudinidae), a parasite specific to the mosquito Aedes albopictus, in Malpighian tubules is initiated by the entry of the trophotozoites developed in the midgut shortly after pupation (usually <5 h). However, only a low proportion of trophozoites are able to migrate; others end up dying. In this study, we demonstrated that those trophozoites that failed to migrate eventually died of apoptosis. Morphological changes such as shrinkage, chromatin aggregations and formation of blunt ridges on the surface were seen in moribund trophozoites. In addition, DNA fragmentation of trophozoites isolated from the midgut of pupae was demonstrated by the presence of DNA ladders, Annexin V staining and TUNEL assays. Detection of caspase-like activity suggests that apoptosis of those trophozoites may have occurred through a mechanism of an intrinsic or mitochondrial-mediated pathway. Although apoptosis has been observed in various protozoan species, it is not clear how apoptosis in single-celled organisms might result from evolution by natural selection. However, we speculate that apoptosis may regulate the parasite load of A. taiwanensis within its natural mosquito host, leading to an optimized state of the survival rate for both parasite and host.
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Affiliation(s)
- Wei-June Chen
- Department of Public Health and Parasitology, Chang Gung University, Kwei-San, Tao-Yuan 33332, Taiwan.
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Ch'ng JH, Yeo SP, Shyong-Wei Tan K. Can a single "powerless" mitochondrion in the malaria parasite contribute to parasite programmed cell death in the asexual stages? Mitochondrion 2012; 13:254-6. [PMID: 23123916 DOI: 10.1016/j.mito.2012.10.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 10/23/2012] [Indexed: 10/27/2022]
Abstract
The protozoan pathogens responsible for malaria are from the Plasmodium genus, with Plasmodium falciparum and Plasmodium vivax accounting for almost all clinical infections. With recent estimates of mortality exceeding 800,000 annually, malaria continues to take a terrible toll on lives and the early promises of medicine to eradicate the disease have yet to approach realization, in part due to the spread of drug resistant parasites. Recent reports of artemisinin-resistance have prompted renewed efforts to identify novel therapeutic options, and one such pathway being considered for antimalarial exploit is the parasite's programmed cell death (PCD) pathway. In this mini-review, we will discuss the roles of the plasmodium mitochondria in cell death and as a target of antimalarial compounds, taking into account recent data suggesting that PCD pathways involving the mitochondria may be attractive antimalarial targets.
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Affiliation(s)
- Jun-Hong Ch'ng
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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47
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Matthews H, Ali M, Carter V, Underhill A, Hunt J, Szor H, Hurd H. Variation in apoptosis mechanisms employed by malaria parasites: the roles of inducers, dose dependence and parasite stages. Malar J 2012; 11:297. [PMID: 22929459 PMCID: PMC3489549 DOI: 10.1186/1475-2875-11-297] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 08/24/2012] [Indexed: 12/14/2022] Open
Abstract
Background Plasmodium berghei ookinetes exhibit an apoptotic phenotype when developing within the mosquito midgut lumen or when cultured in vitro. Markers of apoptosis increase when they are exposed to nitric oxide or reactive oxygen species but high concentrations of hydrogen peroxide cause death without observable signs of apoptosis. Chloroquine and other drugs have been used to induce apoptosis in erythrocytic stages of Plasmodium falciparum and to formulate a putative pathway involving cysteine protease activation and mitochondrial membrane permeabilization; initiated, at least in the case of chloroquine, after its accumulation in the digestive vacuole causes leakage of the vacuole contents. The lack of a digestive vacuole in ookinetes prompted the investigation of the effect of chloroquine and staurosporine on this stage of the life cycle. Finally, the suggestion that apoptosis may have evolved as a strategy employed by ookinetes to increase the fitness of surviving parasites was explored by determining whether increasing the ecological triggers parasite density and nutrient depletion induced apoptosis. Methods Ookinetes were grown in culture then either exposed to hydrogen peroxide, chloroquine or staurosporine, or incubated at different densities and in different media. The proportion of ookinetes displaying positive markers for apoptosis in treated samples was compared with controls and results were analyzed using analysis of variance followed by a Turkey’s test, or a Kruskal-Wallis test as appropriate. Results Hydrogen peroxide below 50 μM triggered apoptosis but cell membranes were rapidly compromised by higher concentrations, and the mode of death could not be defined. Both chloroquine and staurosporine cause a significant increase in ookinetes with condensed chromatin, caspase-like activity and, in the case of chloroquine, phosphatidylserine translocation and DNA fragmentation (not investigated for staurosporine). However, mitochondrial membrane potential remained intact. No relationship between ookinete density and apoptosis was detected but nutrient depletion significantly increased the proportion of ookinetes with chromatin condensation in four hours. Conclusions It is proposed that both a mitochondrial and an amitochondrial apoptotic pathway may be involved, dependent upon the trigger that induces apoptosis, and that pathways may differ between erythrocytic stages and ookinetes, or between rodent and human malaria parasites.
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Affiliation(s)
- Holly Matthews
- Centre for Applied Entomology and Parasitology, Institute for Science and Technology in Medicine, School of Life Sciences, Keele University, Keele, Staffordshire, ST5 5BG, UK
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Jogdand PS, Singh SK, Christiansen M, Dziegiel MH, Singh S, Theisen M. Flow cytometric readout based on Mitotracker Red CMXRos staining of live asexual blood stage malarial parasites reliably assesses antibody dependent cellular inhibition. Malar J 2012; 11:235. [PMID: 22818754 PMCID: PMC3418546 DOI: 10.1186/1475-2875-11-235] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 07/20/2012] [Indexed: 11/10/2022] Open
Abstract
Background Functional in vitro assays could provide insights into the efficacy of malaria vaccine candidates. For estimating the anti-parasite effect induced by a vaccine candidate, an accurate determination of live parasite count is an essential component of most in vitro bioassays. Although traditionally parasites are counted microscopically, a faster, more accurate and less subjective method for counting parasites is desirable. In this study mitochondrial dye (Mitotracker Red CMXRos) was used for obtaining reliable live parasite counts through flow cytometry. Methods Both asynchronous and tightly synchronized asexual blood stage cultures of Plasmodium falciparum were stained with CMXRos and subjected to detection by flow cytometry and fluorescence microscopy. The parasite counts obtained by flow cytometry were compared to standard microscopic counts obtained through examination of Giemsa-stained thin smears. A comparison of the ability of CMXRos to stain live and compromised parasites (induced by either medium starvation or by anti-malarial drug treatment) was carried out. Finally, parasite counts obtained by CMXRos staining through flow cytometry were used to determine specific growth inhibition index (SGI) in an antibody-dependent cellular inhibition (ADCI) assay. Results Mitotracker Red CMXRos can reliably detect live intra-erythrocytic stages of P. falciparum. Comparison between staining of live with compromised parasites shows that CMXRos predominantly stains live parasites with functional mitochondria. Parasite counts obtained by CMXRos staining and flow cytometry were highly reproducible and can reliably determine the ability of IgG from hyper-immune individuals to inhibit parasite growth in presence of monocytes in ADCI assay. Further, a dose-dependent parasite growth inhibitory effect could be detected for both total IgG purified from hyper-immune sera and affinity purified IgGs against the N-terminal non-repeat region of GLURP in ADCI assays coupled with determination of parasite counts through CMXRos staining and flow cytometry. Conclusions A flow cytometry method based on CMXRos staining for detection of live parasite populations has been optimized. This is a rapid and sensitive method with high inter-assay reproducibility which can reliably determine the anti-parasite effect mediated by antibodies in functional in vitro assays such as ADCI assay.
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Affiliation(s)
- Prajakta S Jogdand
- Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
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Gannavaram S, Debrabant A. Programmed cell death in Leishmania: biochemical evidence and role in parasite infectivity. Front Cell Infect Microbiol 2012; 2:95. [PMID: 22919685 PMCID: PMC3417670 DOI: 10.3389/fcimb.2012.00095] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 06/21/2012] [Indexed: 11/13/2022] Open
Abstract
Demonstration of features of a programmed cell death (PCD) pathway in protozoan parasites initiated a great deal of interest and debate in the field of molecular parasitology. Several of the markers typical of mammalian apoptosis have been shown in Leishmania which suggested the existence of an apoptosis like death in these organisms. However, studies to elucidate the downstream events associated with phosphotidyl serine exposure, loss of mitochondrial membrane potential, cytochrome c release, and caspase-like activities in cells undergoing such cell death remain an ongoing challenge. Recent advances in genome sequencing, chemical biology should help to solve some of these challenges. Leishmania genetic mutants that lack putative regulators/effectors of PCD pathway should not only help to demonstrate the mechanisms of PCD but also provide tools to better understand the putative role for this pathway in population control and in the establishment of a successful infection of the host.
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Affiliation(s)
- Sreenivas Gannavaram
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration Bethesda, MD, USA
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50
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Ghosh SK, Butler MS, Lear MJ. Synthesis of 2-C-methylerythritols and 2-C-methylthreitols via enantiodivergent Sharpless dihydroxylation of trisubstituted olefins. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.03.071] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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