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Muhsin-Sharafaldine MR, Abdel Rahman L, Suwanarusk R, Grant J, Parslow G, French N, Tan KSW, Russell B, Morgan XC, Ussher JE. Dientamoeba fragilis associated with microbiome diversity changes in acute gastroenteritis patients. Parasitol Int 2023; 97:102788. [PMID: 37482266 DOI: 10.1016/j.parint.2023.102788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 07/13/2023] [Accepted: 07/13/2023] [Indexed: 07/25/2023]
Abstract
This study examined the correlation between intestinal protozoans and the bacterial microbiome in faecal samples collected from 463 patients in New Zealand who were diagnosed with gastroenteritis. In comparison to traditional microscopic diagnosis methods, Multiplexed-tandem PCR proved to be more effective in detecting intestinal parasites. Among the identified protozoans, Blastocystis sp. and Dientamoeba fragilis were the most prevalent. Notably, D. fragilis was significantly associated with an increase in the alpha-diversity of host prokaryotic microbes. Although the exact role of Blastocystis sp. and D. fragilis as the primary cause of gastroenteritis remains debatable, our data indicates a substantial correlation between these protozoans and the prokaryote microbiome of their hosts, particularly when compared to other protists or patients with gastroenteritis but no detectable parasitic cause. These findings underscore the significance of comprehending the contributions of intestinal protozoans, specifically D. fragilis, to the development of gastroenteritis and their potential implications for disease management.
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Affiliation(s)
| | - L Abdel Rahman
- Department of Microbiology & Immunology, University of Otago, Dunedin, New Zealand
| | - R Suwanarusk
- Department of Microbiology & Immunology, University of Otago, Dunedin, New Zealand
| | - J Grant
- Southern Community Laboratories, Dunedin, New Zealand
| | - G Parslow
- Southern Community Laboratories, Dunedin, New Zealand
| | - N French
- Massey University, Palmerston North, New Zealand
| | - K S W Tan
- Department of Microbiology & Immunology, National University of Singapore, Singapore
| | - B Russell
- Department of Microbiology & Immunology, University of Otago, Dunedin, New Zealand; Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan,.
| | - X C Morgan
- Department of Microbiology & Immunology, University of Otago, Dunedin, New Zealand
| | - J E Ussher
- Department of Microbiology & Immunology, University of Otago, Dunedin, New Zealand; Southern Community Laboratories, Dunedin, New Zealand
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2
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Martín-Escolano R, Ng GC, Tan KSW, Stensvold CR, Gentekaki E, Tsaousis AD. Resistance of Blastocystis to chlorine and hydrogen peroxide. Parasitol Res 2023; 122:167-176. [PMID: 36378332 PMCID: PMC9816239 DOI: 10.1007/s00436-022-07713-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 10/27/2022] [Indexed: 11/16/2022]
Abstract
Blastocystis is a ubiquitous, widely distributed protist inhabiting the gastrointestinal tract of humans and other animals. The organism is genetically diverse, and so far, at least 28 subtypes (STs) have been identified with ST1-ST9 being the most common in humans. The pathogenicity of Blastocystis is controversial. Several routes of transmission have been proposed including fecal-oral (e.g., zoonotic, anthroponotic) and waterborne. Research on the latter has gained traction in the last few years with the organism having been identified in various bodies of water, tap water, and rainwater collection containers including water that has been previously filtered and/or chlorinated. Herein, we assessed the resistance of 11 strains maintained in culture, spanning ST1-ST9 to various chlorine and hydrogen peroxide concentrations for 24 h, and performed recovery assays along with re-exposure. Following the treatment with both compounds, all subtypes showed increased resistance, and viability could be visualized at the cellular level. These results are hinting at the presence of mechanism of resistance to both chlorine and hydrogen peroxide. As such, this pilot study can be the platform for developing guidelines for water treatment processes.
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Affiliation(s)
- Rubén Martín-Escolano
- Laboratory of Molecular and Evolutionary Parasitology, RAPID Group, School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK
| | - Geok Choo Ng
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore
| | - Kevin S W Tan
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore
| | - C Rune Stensvold
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, Artillerivej 5, 2300, Copenhagen S, Denmark
| | - Eleni Gentekaki
- Gut Microbiome Research Group, Mae Fah Luang University, Chiang Rai, 57100, Thailand. .,School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand.
| | - Anastasios D Tsaousis
- Laboratory of Molecular and Evolutionary Parasitology, RAPID Group, School of Biosciences, University of Kent, Canterbury, CT2 7NJ, UK.
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3
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Deng L, Lee JWJ, Tan KSW. Infection with pathogenic Blastocystis ST7 is associated with decreased bacterial diversity and altered gut microbiome profiles in diarrheal patients. Parasit Vectors 2022; 15:312. [PMID: 36064620 PMCID: PMC9446694 DOI: 10.1186/s13071-022-05435-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 08/15/2022] [Indexed: 11/23/2022] Open
Abstract
Background Blastocystis is a common protistan parasite inhabiting the gastrointestinal tract of humans and animals. While there are increasing reports characterizing the associations between Blastocystis and the gut microbiome in healthy individuals, only a few studies have investigated the relationships between Blastocystis and the gut microbiota in diarrheal patients. Methods The effects of a specific subtype (ST7) of Blastocystis on the composition of gut microbiota in diarrheal patients were investigated using 16S ribosomal RNA (rRNA) gene sequencing and bioinformatic analyses. Results Compared with diarrheal patients without Blastocystis, diarrheal patients infected with Blastocystis ST7 exhibited lower bacterial diversity. Beta diversity analysis revealed significant differences in bacterial community structure between ST7-infected and Blastocystis-free patients. The proportion of Enterobacteriaceae and Escherichia-Shigella were significantly enriched in ST7-infected patients. In contrast, the abundance of Bacteroides and Parabacteroides were more prevalent in Blastocystis-free patients. Conclusions The results of this study revealed, for the first time, that infection with Blastocystis ST7 is associated with lower bacterial diversity and altered microbial structure in diarrheal patients. Our study on clinical diarrheal patients is also the first to reinforce the notion that ST7 is a pathogenic subtype of Blastocystis. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05435-z.
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Affiliation(s)
- Lei Deng
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore. .,Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
| | - Jonathan W J Lee
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, 14 Medical Drive, Singapore, 117599, Singapore.,Division of Gastroenterology & Hepatology, National University Hospital, Singapore, 119074, Singapore
| | - Kevin S W Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore. .,Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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Abstract
BACKGROUND Blastocystis ST4 is a common protistan parasite of the gastrointestinal tract of humans and a wide range of animals. While it has been suggested that colonization with ST4 is associated with healthy gut microbiota, how ST4 influences the gut microbiota remains poorly studied. This study aimed to examine the interactions between ST4 and several intestinal bacteria using in vitro co-culture systems, and to further investigate the mechanism of interaction and its effect on the epithelial barrier integrity of HT-29 cells. METHODS Seven intestinal bacteria Bacteroides fragilis, Bifidobacterium longum, Bacillus subtilis, Bacteroides vulgatus, Escherichia coli, Enterococcus faecalis, and Lactobacillus brevis were co-cultured with Blastocystis ST4 in vitro. Flow cytometry and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) were used to determine the role of reactive oxygen species (ROS) and bacteria oxidoreductase genes, respectively, in response to Blastocystis co-incubation. Transepithelial electrical resistance (TEER) and flux assays were performed to assess the effect of microbiota representatives on the integrity of the intestinal epithelial barrier. RESULTS Co-incubation with Blastocystis ST4 showed a beneficial influence on most intestinal bacteria, while ST4 significantly inhibited the growth of B. vulgatus, a common pathogen in the genus Bacteroides. The decrease in B. vulgatus when co-incubated with Blastocystis ST4 was associated with high levels of ROS and the upregulation of oxidative stress-related genes. Furthermore, co-incubation with Blastocystis ST4 was able to protect the intestinal epithelial barrier from damage by B. vulgatus. CONCLUSIONS This study demonstrated, for the first time, that Blastocystis ST4 has beneficial effects on intestinal commensal bacteria in vitro, and can inhibit the growth of pathogenic B. vulgatus. Combined with previous microbiome research on ST4, our data suggest that ST4 may be a beneficial commensal.
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Affiliation(s)
- Lei Deng
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore
| | - Kevin S W Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore.
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5
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Tan YL, Tan KSW, Chu JJH, Chow VT. Combination Treatment With Remdesivir and Ivermectin Exerts Highly Synergistic and Potent Antiviral Activity Against Murine Coronavirus Infection. Front Cell Infect Microbiol 2021; 11:700502. [PMID: 34395311 PMCID: PMC8362885 DOI: 10.3389/fcimb.2021.700502] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/13/2021] [Indexed: 12/16/2022] Open
Abstract
The recent COVID-19 pandemic has highlighted the urgency to develop effective antiviral therapies against the disease. Murine hepatitis virus (MHV) is a coronavirus that infects mice and shares some sequence identity to SARS-CoV-2. Both viruses belong to the Betacoronavirus genus, and MHV thus serves as a useful and safe surrogate model for SARS-CoV-2 infections. Clinical trials have indicated that remdesivir is a potentially promising antiviral drug against COVID-19. Using an in vitro model of MHV infection of RAW264.7 macrophages, the safety and efficacy of monotherapy of remdesivir, chloroquine, ivermectin, and doxycycline were investigated. Of the four drugs tested, remdesivir monotherapy exerted the strongest inhibition of live virus and viral RNA replication of about 2-log10 and 1-log10, respectively (at 6 µM). Ivermectin treatment showed the highest selectivity index. Combination drug therapy was also evaluated using remdesivir (6 µM) together with chloroquine (15 µM), ivermectin (2 µM) or doxycycline (15 µM) – above their IC50 values and at high macrophage cell viability of over 95%. The combination of remdesivir and ivermectin exhibited highly potent synergism by achieving significant reductions of about 7-log10 of live virus and 2.5-log10 of viral RNA in infected macrophages. This combination also resulted in the lowest cytokine levels of IL-6, TNF-α, and leukemia inhibitory factor. The next best synergistic combination was remdesivir with doxycycline, which decreased levels of live virus by ~3-log10 and viral RNA by ~1.5-log10. These results warrant further studies to explore the mechanisms of action of the combination therapy, as well as future in vivo experiments and clinical trials for the treatment of SARS-CoV-2 infection.
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Affiliation(s)
- Yu Ling Tan
- Infectious Diseases Translational Research Program, Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
| | - Kevin S W Tan
- Healthy Longevity Translational Research Program, Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
| | - Justin Jang Hann Chu
- Infectious Diseases Translational Research Program, Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
| | - Vincent T Chow
- Infectious Diseases Translational Research Program, Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
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7
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Deng L, Tay H, Peng G, Lee JWJ, Tan KSW. Prevalence and molecular subtyping of Blastocystis in patients with Clostridium difficile infection, Singapore. Parasit Vectors 2021; 14:277. [PMID: 34030712 PMCID: PMC8142501 DOI: 10.1186/s13071-021-04749-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 04/26/2021] [Indexed: 02/04/2023] Open
Abstract
Background Blastocystis is a common anaerobic colonic protist in humans with controversial pathogenicity. Clostridium difficile (C. difficile) is the commonest cause of infectious diarrhea in healthcare settings. The prevalence and subtype (ST) characteristics of Blastocystis in patients with C. difficile infection (CDI) are rarely documented. Therefore, the present study was conducted to investigate the prevalence and subtype characteristics of Blastocystis in patients with suspicion of CDI in Singapore. Methods Fecal samples were collected from 248 patients presenting with suspected CDI from a single tertiary hospital in Singapore. C. difficile was diagnosed through positive glutamate dehydrogenase (GDH) with or without toxin A/B using enzyme immunoassay methods. The prevalence and subtype genetic characteristics of Blastocystis were determined by polymerase chain reaction (PCR) amplification and analysis of the barcode region of the SSU rRNA gene. Results The proportion of C. difficile in patients with healthcare-associated diarrhea in this study was 44% (109/248). Among the 109 C. difficile-positive patients, 59 (54.1%, 59/109) tested positive for toxigenic C. difficile, which was considered CDI. Based on the sequence analyses of the barcode region of the SSU rRNA gene, 10.1% (25/248) of the patients were found to be Blastocystis-positive, and three subtypes were identified: ST7 (64%, 16/25), ST1 (20%, 5/25), and ST3 (16%, 4/25). Remarkably, we found five patients with Blastocystis and C. difficile coinfection, and further subtype analysis showed two with ST7, two with ST1, and one with ST3. Conclusions To the best of our knowledge, this is the first study to investigate the subtype distributions of Blastocystis in patients with CDI in Singapore. We found ST7 to be the predominant subtype in diarrheal patients. The pathogenicity of ST7 has been strongly suggested in previous in vitro and mouse model experiments, further confirming its potential pathogenicity to humans. ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-021-04749-8.
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Affiliation(s)
- Lei Deng
- Laboratory of Molecular and Cellular Parasitology, Healthy Longevity Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore.,The Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, 611130, Chengdu, Sichuan, People's Republic of China
| | - Huiyi Tay
- Laboratory of Molecular and Cellular Parasitology, Healthy Longevity Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore
| | - Guangneng Peng
- The Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, 611130, Chengdu, Sichuan, People's Republic of China
| | - Jonathan W J Lee
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119228, Singapore.,Department of Gastroenterology and Hepatology, National University Health System, Singapore, 119074, Singapore
| | - Kevin S W Tan
- Laboratory of Molecular and Cellular Parasitology, Healthy Longevity Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore.
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Carrera-Bravo C, Koh EY, Tan KSW. The roles of parasite-derived extracellular vesicles in disease and host-parasite communication. Parasitol Int 2021; 83:102373. [PMID: 33933651 DOI: 10.1016/j.parint.2021.102373] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/14/2021] [Accepted: 04/27/2021] [Indexed: 12/24/2022]
Abstract
In recent years, several parasites have been shown to interact with their hosts through intra- and inter-community communication mechanisms, which were identified to be mediated by extracellular vesicles (EVs) through various uptake mechanisms. EVs are a heterogenous group of nanoparticles (~30-5000 nm) classified into three main types according to their size and biogenesis. EVs contain proteins, lipids, nucleic acids and metabolites from the cell of origin which are essential for genetic exchange, biomarker identification and diagnosis of pathological diseases. As important "forward lines of parasite infectivity", the parasite-secreted EVs function as information transmitters in the early-stage of host-parasite interaction and subsequent host-cell colonization. For this review, we summarize from the literature the relevance of EVs to the pathogenesis and development of human parasitic protistan diseases such as giardiasis, leishmaniasis, amoebiasis, malaria and Blastocystis-mediated gut pathology. Specific in vitro and in vivo interactions of the parasite-EVs and the host, with the reported cellular and immunological outcomes are discussed in this review. EVs have great potential to be further developed as diagnostic, immunomodulation and therapeutic alternatives to fill the knowledge gaps in the current parasitic diseases discussed in this review. Nanomedicine and vaccine development could be explored, with the utilization and/or modification of the parasitic EVs as novel treatment and prevention strategies.
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Affiliation(s)
- Claudia Carrera-Bravo
- Healthy Longevity Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, MD4, 5 Science Drive 2, Singapore 117545, Singapore; A*STAR Infectious Diseases Labs, Agency for Science, Technology and Research, Immunos, Biopolis, Singapore 138648, Singapore.
| | - Eileen Y Koh
- Healthy Longevity Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, MD4, 5 Science Drive 2, Singapore 117545, Singapore
| | - Kevin S W Tan
- Healthy Longevity Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, MD4, 5 Science Drive 2, Singapore 117545, Singapore.
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Abstract
The human gut microbiota is a diverse and complex ecosystem that is involved in beneficial physiological functions as well as disease pathogenesis. Blastocystis is a common protistan parasite and is increasingly recognized as an important component of the gut microbiota. The correlations between Blastocystis and other communities of intestinal microbiota have been investigated, and, to a lesser extent, the role of this parasite in maintaining the host immunological homeostasis. Despite recent studies suggesting that Blastocystis decreases the abundance of beneficial bacteria, most reports indicate that Blastocystis is a common component of the healthy gut microbiome. This review covers recent finding on the potential interactions between Blastocystis and the gut microbiota communities and its roles in regulating host immune responses.
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Affiliation(s)
- Lei Deng
- Laboratory of Molecular and Cellular Parasitology, Healthy Aging Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- The Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Lukasz Wojciech
- Immunology Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Nicholas R. J. Gascoigne
- Immunology Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Guangneng Peng
- The Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Kevin S. W. Tan
- Laboratory of Molecular and Cellular Parasitology, Healthy Aging Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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10
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Affiliation(s)
| | | | - C Graham Clark
- London School of Hygiene and Tropical Medicine, London, UK
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11
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Ahenkorah S, Coertzen D, Tong JX, Fridianto K, Wittlin S, Birkholtz LM, Tan KSW, Lam Y, Go ML, Haynes RK. Antimalarial N 1, N 3-Dialkyldioxonaphthoimidazoliums: Synthesis, Biological Activity, and Structure-activity Relationships. ACS Med Chem Lett 2020; 11:49-55. [PMID: 31938463 DOI: 10.1021/acsmedchemlett.9b00457] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 12/11/2019] [Indexed: 12/19/2022] Open
Abstract
Here we report the nanomolar potencies of N 1,N 3-dialkyldioxonaphthoimidazoliums against asexual forms of sensitive and resistant Plasmodium falciparum. Activity was dependent on the presence of the fused quinone-imidazolium entity and lipophilicity imparted by the N1/N3 alkyl residues on the scaffold. Gametocytocidal activity was also detected, with most members active at IC50 < 1 μM. A representative analog with good solubility, limited PAMPA permeability, and microsomal stability demonstrated oral efficacy on a humanized mouse model of P. falciparum.
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Affiliation(s)
| | - Dina Coertzen
- Institute for Sustainable Malaria Control, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, 0028 Pretoria, South Africa
| | | | | | - Sergio Wittlin
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland
- University of Basel, 4003 Basel, Switzerland
| | - Lyn-Marie Birkholtz
- Institute for Sustainable Malaria Control, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, 0028 Pretoria, South Africa
| | | | | | | | - Richard K. Haynes
- Centre of Excellence for Pharmaceutical Sciences, North-West University, 2531 Potchefstroom, South Africa
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12
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Chua ACY, Ong JJY, Malleret B, Suwanarusk R, Kosaisavee V, Zeeman AM, Cooper CA, Tan KSW, Zhang R, Tan BH, Abas SN, Yip A, Elliot A, Joyner CJ, Cho JS, Breyer K, Baran S, Lange A, Maher SP, Nosten F, Bodenreider C, Yeung BKS, Mazier D, Galinski MR, Dereuddre-Bosquet N, Le Grand R, Kocken CHM, Rénia L, Kyle DE, Diagana TT, Snounou G, Russell B, Bifani P. Robust continuous in vitro culture of the Plasmodium cynomolgi erythrocytic stages. Nat Commun 2019; 10:3635. [PMID: 31406175 PMCID: PMC6690977 DOI: 10.1038/s41467-019-11332-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 06/28/2019] [Indexed: 01/19/2023] Open
Abstract
The ability to culture pathogenic organisms substantially enhances the quest for fundamental knowledge and the development of vaccines and drugs. Thus, the elaboration of a protocol for the in vitro cultivation of the erythrocytic stages of Plasmodium falciparum revolutionized research on this important parasite. However, for P. vivax, the most widely distributed and difficult to treat malaria parasite, a strict preference for reticulocytes thwarts efforts to maintain it in vitro. Cultivation of P. cynomolgi, a macaque-infecting species phylogenetically close to P. vivax, was briefly reported in the early 1980s, but not pursued further. Here, we define the conditions under which P. cynomolgi can be adapted to long term in vitro culture to yield parasites that share many of the morphological and phenotypic features of P. vivax. We further validate the potential of this culture system for high-throughput screening to prime and accelerate anti-P. vivax drug discovery efforts. Present understanding of Plasmodium vivax biology is hampered by its inability to grow in vitro. Here, the authors developed an in vitro culture of its simian counterpart, P. cynomolgi, which shares morphological and phenotypic similarities with P. vivax, initiating a new phase in vivax research.
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Affiliation(s)
- Adeline C Y Chua
- Singapore Immunology Network, A*STAR, Singapore, 138648, Singapore.,Department of Microbiology and Immunology, University of Otago, Dunedin, 9054, New Zealand.,Novartis Institute for Tropical Diseases, Singapore, 138670, Singapore
| | - Jessica Jie Ying Ong
- Department of Microbiology and Immunology, University of Otago, Dunedin, 9054, New Zealand.,Novartis Institute for Tropical Diseases, Singapore, 138670, Singapore
| | - Benoit Malleret
- Singapore Immunology Network, A*STAR, Singapore, 138648, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119077, Singapore
| | - Rossarin Suwanarusk
- Singapore Immunology Network, A*STAR, Singapore, 138648, Singapore.,Department of Microbiology and Immunology, University of Otago, Dunedin, 9054, New Zealand
| | - Varakorn Kosaisavee
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119077, Singapore.,Department of Parasitology and Entomology, Faculty of Public Health, Mahidol University, Bangkok, 10400, Thailand
| | - Anne-Marie Zeeman
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, 2288, The Netherlands
| | - Caitlin A Cooper
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, 30602, USA
| | - Kevin S W Tan
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119077, Singapore
| | - Rou Zhang
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119077, Singapore
| | - Bee Huat Tan
- Novartis Institute for Tropical Diseases, Singapore, 138670, Singapore
| | | | - Andy Yip
- Novartis Institute for Tropical Diseases, Singapore, 138670, Singapore
| | - Anne Elliot
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, 30602, USA
| | - Chester J Joyner
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Emory University, Atlanta, 30322, USA.,Emory Vaccine Center, Emory University, Atlanta, 30317, USA
| | - Jee Sun Cho
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119077, Singapore
| | - Kate Breyer
- Laboratory Animal Services, Scientific Operations, Novartis Institutes for Biomedical Research, East Hanover, 07936-1080, USA
| | - Szczepan Baran
- Laboratory Animal Services, Scientific Operations, Novartis Institutes for Biomedical Research, East Hanover, 07936-1080, USA
| | - Amber Lange
- Laboratory Animal Services, Scientific Operations, Novartis Institutes for Biomedical Research, East Hanover, 07936-1080, USA
| | - Steven P Maher
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, 30602, USA
| | - François Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, 63110, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford, OX3 7FZ, UK
| | | | - Bryan K S Yeung
- Novartis Institute for Tropical Diseases, Singapore, 138670, Singapore
| | - Dominique Mazier
- Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), Paris, F-75013, France.,CIMI-Paris, INSERM, U1135, CNRS, Paris, F-75013, France
| | - Mary R Galinski
- Emory Vaccine Center, Emory University, Atlanta, 30317, USA.,Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, 30322, USA
| | - Nathalie Dereuddre-Bosquet
- CEA-Université Paris Sud 11-INSERM U1184, Immunology of Viral Infections and Autoimmune Diseases (IMVA), IDMIT Department, IBJF, DRF, Fontenay-aux-Roses, 92265, France
| | - Roger Le Grand
- CEA-Université Paris Sud 11-INSERM U1184, Immunology of Viral Infections and Autoimmune Diseases (IMVA), IDMIT Department, IBJF, DRF, Fontenay-aux-Roses, 92265, France
| | - Clemens H M Kocken
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, 2288, The Netherlands
| | - Laurent Rénia
- Singapore Immunology Network, A*STAR, Singapore, 138648, Singapore.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119077, Singapore
| | - Dennis E Kyle
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, 30602, USA
| | - Thierry T Diagana
- Novartis Institute for Tropical Diseases, Singapore, 138670, Singapore
| | - Georges Snounou
- Sorbonne Universités, UPMC Univ Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), Paris, F-75013, France.,CIMI-Paris, INSERM, U1135, CNRS, Paris, F-75013, France.,CEA-Université Paris Sud 11-INSERM U1184, Immunology of Viral Infections and Autoimmune Diseases (IMVA), IDMIT Department, IBJF, DRF, Fontenay-aux-Roses, 92265, France
| | - Bruce Russell
- Department of Microbiology and Immunology, University of Otago, Dunedin, 9054, New Zealand.
| | - Pablo Bifani
- Singapore Immunology Network, A*STAR, Singapore, 138648, Singapore. .,Novartis Institute for Tropical Diseases, Singapore, 138670, Singapore. .,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119077, Singapore. .,Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK.
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13
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Li FJ, Tsaousis AD, Purton T, Chow VTK, He CY, Tan KSW. Successful Genetic Transfection of the Colonic Protistan Parasite Blastocystis for Reliable Expression of Ectopic Genes. Sci Rep 2019; 9:3159. [PMID: 30816225 PMCID: PMC6395660 DOI: 10.1038/s41598-019-39094-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/17/2019] [Indexed: 02/06/2023] Open
Abstract
The microbial parasite Blastocystis colonizes the large intestines of numerous animal species and increasing evidence has linked Blastocystis infection to enteric diseases with signs and symptoms including abdominal pain, constipation, diarrhea, nausea, vomiting, and flatulence. It has also recently been reported to be an important member of the host intestinal microbiota. Despite significant advances in our understanding of Blastocystis cell biology and host-parasite interactions, a genetic modification tool is absent. In this study, we successfully established a robust gene delivery protocol for Blastocystis subtype 7 (ST7) and ectopic protein expression was further tested using a high sensitivity nano-luciferase (Nluc) reporter system, with promoter regions from several genes. Among them, a strong promoter encompassing a region upstream of the legumain 5' UTR was identified. Using this promoter combined with the legumain 3' UTR, which contains a conserved, precise polyadenylation signal, a robust transient transfection technique was established for the first time in Blastocystis. This system was validated by ectopic expression of proteins harbouring specific localization signals. The establishment of a robust, reproducible gene modification system for Blastocystis is a significant advance for Blastocystis research both in vitro and in vivo. This technique will spearhead further research to understand the parasite's biology, its role in health and disease, along with novel ways to combat the parasite.
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Affiliation(s)
- Feng-Jun Li
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore.,Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
| | - Anastasios D Tsaousis
- Laboratory of Molecular and Evolutionary Parasitology, RAPID group, School of Biosciences, University of Kent, Canterbury, CT2 7NJ, United Kingdom
| | - Tracy Purton
- Laboratory of Molecular and Evolutionary Parasitology, RAPID group, School of Biosciences, University of Kent, Canterbury, CT2 7NJ, United Kingdom
| | - Vincent T K Chow
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore
| | - Cynthia Y He
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore.
| | - Kevin S W Tan
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore.
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14
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Gautam N, Sankaran S, Yason JA, Tan KSW, Gascoigne NRJ. A high content imaging flow cytometry approach to study mitochondria in T cells: MitoTracker Green FM dye concentration optimization. Methods 2017; 134-135:11-19. [PMID: 29198814 DOI: 10.1016/j.ymeth.2017.11.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/03/2017] [Accepted: 11/27/2017] [Indexed: 02/07/2023] Open
Abstract
Mitochondria, the powerhouse of the cell, are known to remodel their membrane structures through the process of fusion or fission. Studies have indicated that T cells adopt different energy metabolic phenotypes, namely oxidative phosphorylation and glycolysis depending on whether they are naïve, effector and memory T cells. It has recently been shown that changes in mitochondrial morphology dictate T cell fate via regulation of their metabolism. Our keen interest in T cell function and metabolism led us to explore and establish a method to study mitochondria in live T cells through a novel high content approach called Imaging Flow Cytometry (IFC). The focus of our current study was on developing a protocol to standardize the concentration of MitoTracker Green FM dye to observe mitochondria in live T cells using IFC. We began the study by using widefield microscopy to confirm the localisation of MitoTracker Green FM labelled mitochondria in live T cells. This was followed by testing various concentrations of the dye to achieve a similar labelling pattern using IFC while eliminating false positive or negative staining. The optimization of the method used to label the mitochondria by IFC for analysis included standardisation of a number of important parameters such as dye concentration, voltage, fluorescence intensity values for acquisition and processing. IFC could potentially be a powerful method to study T cells in a relatively high throughput manner.
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Affiliation(s)
- Namrata Gautam
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, and Immunology Programme, National University of Singapore, Singapore
| | - Shvetha Sankaran
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, and Immunology Programme, National University of Singapore, Singapore
| | - John A Yason
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Kevin S W Tan
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Nicholas R J Gascoigne
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, and Immunology Programme, National University of Singapore, Singapore.
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15
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Armengaud J, Pible O, Gaillard JC, Cian A, Gantois N, Tan KSW, Chabé M, Viscogliosi E. Proteogenomic Insights into the Intestinal Parasite Blastocystis
sp. Subtype 4 Isolate WR1. Proteomics 2017; 17. [DOI: 10.1002/pmic.201700211] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/09/2017] [Indexed: 12/15/2022]
Affiliation(s)
- Jean Armengaud
- Laboratoire Innovations technologiques pour la Détection et le Diagnostic (Li2D); Service de Pharmacologie et Immunoanalyse (SPI); CEA, INRA; Gif-Sur-Yvette France
| | - Olivier Pible
- Laboratoire Innovations technologiques pour la Détection et le Diagnostic (Li2D); Service de Pharmacologie et Immunoanalyse (SPI); CEA, INRA; Gif-Sur-Yvette France
| | - Jean-Charles Gaillard
- Laboratoire Innovations technologiques pour la Détection et le Diagnostic (Li2D); Service de Pharmacologie et Immunoanalyse (SPI); CEA, INRA; Gif-Sur-Yvette France
| | - Amandine Cian
- Université de Lille; CNRS, Inserm, CHU Lille; Institut Pasteur de Lille; U1019-UMR 8204-CIIL-Centre d'Infection et d'Immunité de Lille; 1 rue du Professeur Calmette, Lille, France
| | - Nausicaa Gantois
- Université de Lille; CNRS, Inserm, CHU Lille; Institut Pasteur de Lille; U1019-UMR 8204-CIIL-Centre d'Infection et d'Immunité de Lille; 1 rue du Professeur Calmette, Lille, France
| | - Kevin S. W. Tan
- Laboratory of Molecular and Cellular Parasitology; Department of Microbiology and Immunology; Yong Loo Lin School of Medicine; National University of Singapore; Singapore Singapore
| | - Magali Chabé
- Université de Lille; CNRS, Inserm, CHU Lille; Institut Pasteur de Lille; U1019-UMR 8204-CIIL-Centre d'Infection et d'Immunité de Lille; 1 rue du Professeur Calmette, Lille, France
| | - Eric Viscogliosi
- Université de Lille; CNRS, Inserm, CHU Lille; Institut Pasteur de Lille; U1019-UMR 8204-CIIL-Centre d'Infection et d'Immunité de Lille; 1 rue du Professeur Calmette, Lille, France
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16
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Li FJ, Xu ZS, Aye HM, Brasseur A, Lun ZR, Tan KSW, He CY. An efficient cumate-inducible system for procyclic and bloodstream form Trypanosoma brucei. Mol Biochem Parasitol 2017; 214:101-104. [PMID: 28438458 DOI: 10.1016/j.molbiopara.2017.04.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 04/17/2017] [Accepted: 04/18/2017] [Indexed: 12/18/2022]
Abstract
In Trypanosoma brucei, the tetracycline-inducible system enables tightly-regulated, highly-efficient expression of recombinant proteins or double-stranded RNA in both procyclic and bloodstream form cells, providing useful molecular genetic tools to study gene functions. An alternative, vanillic acid-inducible system is recently described for procyclic T. brucei, providing ∼18-fold increase in GFP reporter expression upon induction (Sunter JD. Mol. Biochem. Parasitol. 2016, 207:45-48). Here we describe a cumate-inducible system that allows efficient, tunable gene expression showing >300-fold increase in GFP expression upon induction. The cumate-inducible system can be used alone or together with the tetracycline-inducible system, in both procyclic and bloodstream form T. brucei. Efficient cumate-inducible expression is also achieved in T. brucei-infected mice.
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Affiliation(s)
- Feng-Jun Li
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore.
| | - Zhi-Shen Xu
- State Key Laboratory of Biocontrol, School of Life Sciences, Key Laboratory of Tropical Diseases and Control of the Ministry of Education, Zhongshan Medical School, Sun Yat-Sen University, Guangzhou 510275, China
| | - Htay Mon Aye
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Anaïs Brasseur
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Zhao-Rong Lun
- State Key Laboratory of Biocontrol, School of Life Sciences, Key Laboratory of Tropical Diseases and Control of the Ministry of Education, Zhongshan Medical School, Sun Yat-Sen University, Guangzhou 510275, China
| | - Kevin S W Tan
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Cynthia Y He
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore; Centre for BioImaging Sciences, National University of Singapore, Singapore 117543, Singapore.
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17
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Li FJ, Tan KSW, He CY. BAPTA-AM decreases cellular pH, inhibits acidocalcisome acidification and autophagy in amino acid-starved T. brucei. Mol Biochem Parasitol 2017; 213:26-29. [PMID: 28274857 DOI: 10.1016/j.molbiopara.2017.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 03/02/2017] [Accepted: 03/02/2017] [Indexed: 11/28/2022]
Abstract
To investigate the role of Ca2+ signaling in starvation-induced autophagy in Trypanosoma brucei, the causative agent of human African trypanosomiasis, we used cell-permeant Ca2+ chelator BAPTA-AM and cell impermeant chelator EGTA, and examined the potential involvement of several intracellular Ca2+ signaling pathways in T. brucei autophagy. The results showed an unexpected effect of BAPTA-AM in decreasing cellular pH and inhibiting acidocalcisome acidification in starved cells. The implication of these results in the role of Ca2+ signaling and cellular/organellar pH in T. brucei autophagy is discussed.
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Affiliation(s)
- Feng-Jun Li
- Department of Biological Sciences, National University of Singapore, 117543, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore.
| | - Kevin S W Tan
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Cynthia Y He
- Department of Biological Sciences, National University of Singapore, 117543, Singapore; Centre for BioImaging Sciences, National University of Singapore, 117543, Singapore.
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18
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Ajjampur SSR, Png CW, Chia WN, Zhang Y, Tan KSW. Ex Vivo and In Vivo Mice Models to Study Blastocystis spp. Adhesion, Colonization and Pathology: Closer to Proving Koch's Postulates. PLoS One 2016; 11:e0160458. [PMID: 27508942 PMCID: PMC4979897 DOI: 10.1371/journal.pone.0160458] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/19/2016] [Indexed: 12/22/2022] Open
Abstract
Blastocystis spp. are widely prevalent extra cellular, non-motile anerobic protists that inhabit the gastrointestinal tract. Although Blastocystis spp. have been associated with gastrointestinal symptoms, irritable bowel syndrome and urticaria, their clinical significance has remained controversial. We established an ex vivo mouse explant model to characterize adhesion in the context of tissue architecture and presence of the mucin layer. Using confocal microscopy with tissue whole mounts and two axenic isolates of Blastocystis spp., subtype 7 with notable differences in adhesion to intestinal epithelial cells (IEC), isolate B (ST7-B) and isolate H (more adhesive, ST7-H), we showed that adhesion is both isolate dependent and tissue trophic. The more adhesive isolate, ST7-H was found to bind preferentially to the colon tissue than caecum and terminal ileum. Both isolates were also found to have mucinolytic effects. We then adapted a DSS colitis mouse model as a susceptible model to study colonization and acute infection by intra-caecal inoculation of trophic Blastocystis spp.cells. We found that the more adhesive isolate ST7-H was also a better colonizer with more mice shedding parasites and for a longer duration than ST7-B. Adhesion and colonization was also associated with increased virulence as ST7-H infected mice showed greater tissue damage than ST7-B. Both the ex vivo and in vivo models used in this study showed that Blastocystis spp. remain luminal and predominantly associated with mucin. This was further confirmed using colonic loop experiments. We were also successfully able to re-infect a second batch of mice with ST7-H isolates obtained from fecal cultures and demonstrated similar histopathological findings and tissue damage thereby coming closer to proving Koch’s postulates for this parasite.
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Affiliation(s)
- Sitara S. R. Ajjampur
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, National University of Singapore, 5 Science Drive 2, Singapore, 117545
| | - Chin Wen Png
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, National University of Singapore, 5 Science Drive 2, Singapore, 117545
| | - Wan Ni Chia
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, National University of Singapore, 5 Science Drive 2, Singapore, 117545
| | - Yongliang Zhang
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, National University of Singapore, 5 Science Drive 2, Singapore, 117545
| | - Kevin S. W. Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, National University of Singapore, 5 Science Drive 2, Singapore, 117545
- * E-mail:
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19
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Ajjampur SSR, Tan KSW. Pathogenic mechanisms in Blastocystis spp. - Interpreting results from in vitro and in vivo studies. Parasitol Int 2016; 65:772-779. [PMID: 27181702 DOI: 10.1016/j.parint.2016.05.007] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 05/04/2016] [Accepted: 05/11/2016] [Indexed: 01/20/2023]
Abstract
Blastocystis spp. are commonly reported intestinal protists but whose clinical significance remains controversial. Infections have ranged from asymptomatic carriage to non-specific gastrointestinal symptoms and have also been linked to irritable bowel syndrome and urticaria in some patient populations. In vitro studies showed that both parasite and parasite lysates have damaging effects on intestinal epithelial cells causing apoptosis and degradation of tight junction proteins occludin and ZO1, resulting in increased intestinal permeability. Adhesion of trophic forms to the intestinal epithelium and release of cysteine proteases appear to be the major triggers leading to pathogenesis. Two putative virulence factors identified are cysteine proteases legumain and cathepsin B. Blastocystis spp. also have immuno-modulatory effects including degradation of IgA, inhibition of iNOS and upregulation of proinflammatory cytokines, IL8 and GM-CSF in intestinal epithelial cells and IL1β, IL6 and TNFα in murine macrophages. Blastocystis spp. have also been reported to dampen response to LPS in intestinal epithelial cells and monocytes. Studies in rodent models and naturally infected pigs have shown that the parasite localizes to the lumen and mucosal surface of the large intestine mostly in the caecum and colon. The parasite has been found to cause mucosal sloughing, increase in goblet cell mucin, increased intestinal permeability and to induce a pro-inflammatory cytokine response with upregulation of TNFα, IFNγ and IL12. In this review, we summarize findings from in vitro and in vivo studies that demonstrate pathogenic potential but also show considerable inter and intra subtype variation, which provides a plausible explanation on the conflicting reports on clinical significance.
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Affiliation(s)
- Sitara S R Ajjampur
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, National University of Singapore, Singapore
| | - Kevin S W Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, National University of Singapore, Singapore.
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20
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Koh HX, Aye HM, Tan KSW, He CY. The lysosomotropic drug LeuLeu-OMe induces lysosome disruption and autophagy-independent cell death in Trypanosoma brucei. Microb Cell 2015; 2:288-298. [PMID: 28357304 PMCID: PMC5349101 DOI: 10.15698/mic2015.08.217] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Trypanosoma brucei is a blood-borne, protozoan parasite that causes African sleeping sickness in humans and nagana in animals. The current chemotherapy relies on only a handful of drugs that display undesirable toxicity, poor efficacy and drug-resistance. In this study, we explored the use of lysosomotropic drugs to induce bloodstream form T. brucei cell death via lysosome destabilization. METHODS We measured drug concentrations that inhibit cell proliferation by 50% (IC<sub>50<sub>) for several compounds, chosen based on their lysosomotropic effects previously reported in Plasmodium falciparum. The lysosomal effects and cell death induced by L-leucyl-L-leucyl methyl ester (LeuLeu-OMe) were further analyzed by flow cytometry and immunofluorescence analyses of different lysosomal markers. The effect of autophagy in LeuLeu-OMe-induced lysosome destabilization and cytotoxicity was also investigated in control and autophagy-deficient cells. RESULTS LeuLeu-OMe was selected for detailed analyses due to its strong inhibitory profile against T. brucei with minimal toxicity to human cell lines in vitro. Time-dependent immunofluorescence studies confirmed an effect of LeuLeu-OMe on the lysosome. LeuLeu-OMe-induced cytotoxicity was also found to be dependent on the acidic pH of the lysosome. Although an increase in autophagosomes was observed upon LeuLeu-OMe treatment, autophagy was not required for the cell death induced by LeuLeu-OMe. Necrosis appeared to be the main cause of cell death upon LeuLeu-OMe treatment. CONCLUSIONS LeuLeu-OMe is a lysosomotropic agent capable of destabilizing lysosomes and causing necrotic cell death in bloodstream form of T. brucei.
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Affiliation(s)
- Hazel X Koh
- Department of Biological Sciences, National University of Singapore. ; Department of Microbiology, National University of Singapore
| | - Htay M Aye
- Department of Biological Sciences, National University of Singapore
| | - Kevin S W Tan
- Department of Microbiology, National University of Singapore
| | - Cynthia Y He
- Department of Biological Sciences, National University of Singapore
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21
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Wawrzyniak I, Courtine D, Osman M, Hubans-Pierlot C, Cian A, Nourrisson C, Chabe M, Poirier P, Bart A, Polonais V, Delgado-Viscogliosi P, El Alaoui H, Belkorchia A, van Gool T, Tan KSW, Ferreira S, Viscogliosi E, Delbac F. Draft genome sequence of the intestinal parasite Blastocystis subtype 4-isolate WR1. Genom Data 2015; 4:22-3. [PMID: 26484170 PMCID: PMC4535960 DOI: 10.1016/j.gdata.2015.01.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 01/23/2015] [Accepted: 01/24/2015] [Indexed: 11/27/2022]
Abstract
The intestinal protistan parasite Blastocystis is characterized by an extensive genetic variability with 17 subtypes (ST1–ST17) described to date. Only the whole genome of a human ST7 isolate was previously sequenced. Here we report the draft genome sequence of Blastocystis ST4-WR1 isolated from a laboratory rodent at Singapore.
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Affiliation(s)
- Ivan Wawrzyniak
- Clermont Université, Université Blaise Pascal-Université d'Auvergne-CNRS, UMR 6023 Laboratoire Microorganismes: Génome et Environnement, Clermont-Ferrand, France
| | - Damien Courtine
- Clermont Université, Université Blaise Pascal-Université d'Auvergne-CNRS, UMR 6023 Laboratoire Microorganismes: Génome et Environnement, Clermont-Ferrand, France
| | - Marwan Osman
- Institut Pasteur de Lille, Centre d'Infection et d'Immunité de Lille, Inserm U1019, CNRS UMR 8204, Université Lille, Nord de France, France
| | | | - Amandine Cian
- Institut Pasteur de Lille, Centre d'Infection et d'Immunité de Lille, Inserm U1019, CNRS UMR 8204, Université Lille, Nord de France, France
| | - Céline Nourrisson
- Clermont Université, Université Blaise Pascal-Université d'Auvergne-CNRS, UMR 6023 Laboratoire Microorganismes: Génome et Environnement, Clermont-Ferrand, France
| | - Magali Chabe
- Institut Pasteur de Lille, Centre d'Infection et d'Immunité de Lille, Inserm U1019, CNRS UMR 8204, Université Lille, Nord de France, France
| | - Philippe Poirier
- Clermont Université, Université Blaise Pascal-Université d'Auvergne-CNRS, UMR 6023 Laboratoire Microorganismes: Génome et Environnement, Clermont-Ferrand, France
| | - Aldert Bart
- Department of Medical Microbiology, Section Parasitology, Center for Infection and Immunity Amsterdam, Academic Medical Center, Amsterdam, The Netherlands
| | - Valérie Polonais
- Clermont Université, Université Blaise Pascal-Université d'Auvergne-CNRS, UMR 6023 Laboratoire Microorganismes: Génome et Environnement, Clermont-Ferrand, France
| | - Pilar Delgado-Viscogliosi
- Institut Pasteur de Lille, Centre d'Infection et d'Immunité de Lille, Inserm U1019, CNRS UMR 8204, Université Lille, Nord de France, France
| | - Hicham El Alaoui
- Clermont Université, Université Blaise Pascal-Université d'Auvergne-CNRS, UMR 6023 Laboratoire Microorganismes: Génome et Environnement, Clermont-Ferrand, France
| | - Abdel Belkorchia
- Clermont Université, Université Blaise Pascal-Université d'Auvergne-CNRS, UMR 6023 Laboratoire Microorganismes: Génome et Environnement, Clermont-Ferrand, France
| | - Tom van Gool
- Department of Medical Microbiology, Section Parasitology, Center for Infection and Immunity Amsterdam, Academic Medical Center, Amsterdam, The Netherlands
| | - Kevin S W Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | | | - Eric Viscogliosi
- Institut Pasteur de Lille, Centre d'Infection et d'Immunité de Lille, Inserm U1019, CNRS UMR 8204, Université Lille, Nord de France, France
| | - Frédéric Delbac
- Clermont Université, Université Blaise Pascal-Université d'Auvergne-CNRS, UMR 6023 Laboratoire Microorganismes: Génome et Environnement, Clermont-Ferrand, France
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22
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Teo JDW, MacAry PA, Tan KSW. Pleiotropic effects of Blastocystis spp. Subtypes 4 and 7 on ligand-specific toll-like receptor signaling and NF-κB activation in a human monocyte cell line. PLoS One 2014; 9:e89036. [PMID: 24551212 PMCID: PMC3925187 DOI: 10.1371/journal.pone.0089036] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 01/19/2014] [Indexed: 12/23/2022] Open
Abstract
Blastocystis spp. is a common enteric stramenopile parasite that colonizes the colon of hosts of a diverse array of species, including humans. It has been shown to compromise intestinal epithelial cell barrier integrity and mediate the production of pro-inflammatory cytokines and chemokines. Mucosal epithelial surfaces, including the intestinal epithelium, are increasingly recognized to perform a vital surveillance role in the context of innate immunity, through the expression of pathogen recognition receptors, such as Toll-like receptors (TLRs). In this study, we use the human TLR reporter monocytic cell line, THP1-Blue, which expresses all human TLRs, to investigate effects of Blastocystis on TLR activation, more specifically the activation of TLR-2, -4 and -5. We have observed that live Blastocystis spp. parasites and whole cell lysate (WCL) alone do not activate TLRs in THP1-Blue. Live ST4-WR1 parasites inhibited LPS-mediated NF-κB activation in THP1-Blue. In contrast, ST7-B WCL and ST4-WR1 WCL induced pleiotropic modulation of ligand-specific TLR-2 and TLR-4 activation, with no significant effects on flagellin-mediated TLR-5 activation. Real time-qPCR analysis on SEAP reporter gene confirmed the augmenting effect of ST7-B on LPS-mediated NF-κB activation in THP1-Blue. Taken together, this is the first study to characterize interactions between Blastocystis spp. and host TLR activation using an in vitro reporter model.
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Affiliation(s)
- Joshua D. W. Teo
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Paul A. MacAry
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Program, National University of Singapore, Singapore, Singapore
| | - Kevin S. W. Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- * E-mail:
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23
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Shi H, Liu Z, Li A, Yin J, Chong AGL, Tan KSW, Zhang Y, Lim CT. Life cycle-dependent cytoskeletal modifications in Plasmodium falciparum infected erythrocytes. PLoS One 2013; 8:e61170. [PMID: 23585879 PMCID: PMC3621960 DOI: 10.1371/journal.pone.0061170] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 03/07/2013] [Indexed: 11/19/2022] Open
Abstract
Plasmodium falciparum infection of human erythrocytes is known to result in the modification of the host cell cytoskeleton by parasite-coded proteins. However, such modifications and corresponding implications in malaria pathogenesis have not been fully explored. Here, we probed the gradual modification of infected erythrocyte cytoskeleton with advancing stages of infection using atomic force microscopy (AFM). We reported a novel strategy to derive accurate and quantitative information on the knob structures and their connections with the spectrin network by performing AFM-based imaging analysis of the cytoplasmic surface of infected erythrocytes. Significant changes on the red cell cytoskeleton were observed from the expansion of spectrin network mesh size, extension of spectrin tetramers and the decrease of spectrin abundance with advancing stages of infection. The spectrin network appeared to aggregate around knobs but also appeared sparser at non-knob areas as the parasite matured. This dramatic modification of the erythrocyte skeleton during the advancing stage of malaria infection could contribute to the loss of deformability of the infected erythrocyte.
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Affiliation(s)
- Hui Shi
- Nano Biomechanics Laboratory, Department of Bioengineering, National University of Singapore, Singapore, Singapore
| | - Zhuo Liu
- Infrastructure System Laboratory, Department of Civil Engineering, National University of Singapore, Singapore, Singapore
| | - Ang Li
- Singapore-MIT Alliance (SMA), National University of Singapore, Singapore, Singapore
| | - Jing Yin
- Laboratory of Molecular and Cellular Parasitology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Alvin G. L. Chong
- Laboratory of Molecular and Cellular Parasitology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Kevin S. W. Tan
- Laboratory of Molecular and Cellular Parasitology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Yong Zhang
- Nano Biomechanics Laboratory, Department of Bioengineering, National University of Singapore, Singapore, Singapore
| | - Chwee Teck Lim
- Nano Biomechanics Laboratory, Department of Bioengineering, National University of Singapore, Singapore, Singapore
- Singapore-MIT Alliance (SMA), National University of Singapore, Singapore, Singapore
- Department of Mechanical Engineering, National University of Singapore, Singapore, Singapore
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
- * E-mail:
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24
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Chan CL, Rénia L, Tan KSW. A simplified, sensitive phagocytic assay for malaria cultures facilitated by flow cytometry of differentially-stained cell populations. PLoS One 2012; 7:e38523. [PMID: 22675573 PMCID: PMC3366917 DOI: 10.1371/journal.pone.0038523] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 05/10/2012] [Indexed: 11/30/2022] Open
Abstract
Background Phagocytosis of infected and uninfected erythrocytes is an important feature of malaria infections. Flow cytometry is a useful tool for studying phagocytic uptake of malaria-infected erythrocytes in vitro. However, current approaches are limited by the inability to discriminate between infected and uninfected erythrocytes and a failure to stain the early developmental ring stages of infected erythrocytes. The majority of infected erythrocytes in circulation are of the ring stage and these are therefore important targets to study. Methodology/Principal Findings In vitro P. falciparum cultures comprising infected and uninfected erythrocytes were labeled and exposed to cells derived from the human monocytic THP-1 cell line. Phagocytosis was assayed by flow cytometry. Dual labeling of Plasmodium DNA and erythrocyte cytoplasm with dihydroethidium and CellTrace™ Violet respectively allowed, for the first time, the detection and enumeration of phagocytes with ingested erythrocytes from both early ring- and late schizont-stage P, falciparum cultures. The sensitivity of the method was tested using varying conditions including phagocyte type (monocytes versus macrophages), parasite stage (rings versus schizonts), and negative (incubation with cytochalasin D) and positive (incubation with immune sera) effectors of phagocytosis. The current assay clearly demonstrated uptake of infected and uninfected erythrocytes exposed to phagocytes; the extent of which was dependent on the conditions mentioned. Conclusions We describe a simple, sensitive and rapid method for quantifying phagocytosis of P. falciparum-infected erythrocytes, by flow cytometry. This approach can be applied for studying parasite-phagocyte interactions under a variety of conditions. The investigation of phagocytosis of P. falciparum-infected erythrocytes can extend from looking solely at late-staged infected erythrocytes to include early-staged ones as well. It does away with the need to purify infected cells, allowing the study of effects on neighboring uninfected cells. This method may also be translated for use with different types of phagocytes.
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Affiliation(s)
- Chuu Ling Chan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Laurent Rénia
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Laboratory of Malaria Immunobiology, Singapore Immunology Network, Immunos, Singapore, Singapore
| | - Kevin S. W. Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- * E-mail:
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25
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Mirza H, Wu Z, Teo JDW, Tan KSW. Statin pleiotropy prevents rho kinase-mediated intestinal epithelial barrier compromise induced by Blastocystis cysteine proteases. Cell Microbiol 2012; 14:1474-84. [PMID: 22587300 DOI: 10.1111/j.1462-5822.2012.01814.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 05/08/2012] [Accepted: 05/09/2012] [Indexed: 12/31/2022]
Abstract
Blastocystis is an enteric parasite that causes acute and chronic intestinal infections, often non-responsive to conventional antibiotics. The effects of Blastocystis infections on human epithelial permeability are not known, and molecular mechanisms of Blastocystis-induced intestinal pathology remain unclear. This study was conducted to determine whether Blastocystis species alters human intestinal epithelial permeability, to assess whether these abnormalities are rho kinase (ROCK)-dependent, and to investigate the therapeutic potential of the HMG-CoA reductase inhibitor Simvastatin in altered intestinal epithelial barrier function. The effect of metronidazole resistant (Mz(r)) Blastocystis isolated from a symptomatic patient on human colonic epithelial monolayers (Caco-2) was assessed. Modulation of enterocyte myosin light chain phosphorylation, transepithelial fluorescein isothiocyanate-dextran fluxes, transepithelial resistance, cytoskeletal F-actin and tight junctional zonula occludens-1 (ZO-1) by parasite cysteine proteases were measured in the presence or absence of HMG-CoA reductase and ROCK inhibition. Blastocystis significantly decreased transepithelial resistance, increased epithelial permeability, phosphorylated myosin light chain and reorganized epithelial actin cytoskeleton and ZO-1. These alterations were abolished by inhibition of enterocyte ROCK, HMG-CoA reductase and parasite cysteine protease. Our findings suggest that cysteine proteases of Mz(r) Blastocystis induce ROCK-dependent disruption of intestinal epithelial barrier function and correlates with reorganization of cytoskeletal F-actin and tight junctional ZO-1. Simvastatin prevented parasite-induced barrier-compromise, suggesting a therapeutic potential of statins in intestinal infections.
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Affiliation(s)
- Haris Mirza
- Singapore Immunology Network, Biomedical Sciences Institutes, Agency for Science, Technology and Research, 8A Biomedical Grove, Immunos, Singapore 138648, Singapore
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Klionsky DJ, Abdalla FC, Abeliovich H, Abraham RT, Acevedo-Arozena A, Adeli K, Agholme L, Agnello M, Agostinis P, Aguirre-Ghiso JA, Ahn HJ, Ait-Mohamed O, Ait-Si-Ali S, Akematsu T, Akira S, Al-Younes HM, Al-Zeer MA, Albert ML, Albin RL, Alegre-Abarrategui J, Aleo MF, Alirezaei M, Almasan A, Almonte-Becerril M, Amano A, Amaravadi R, Amarnath S, Amer AO, Andrieu-Abadie N, Anantharam V, Ann DK, Anoopkumar-Dukie S, Aoki H, Apostolova N, Arancia G, Aris JP, Asanuma K, Asare NYO, Ashida H, Askanas V, Askew DS, Auberger P, Baba M, Backues SK, Baehrecke EH, Bahr BA, Bai XY, Bailly Y, Baiocchi R, Baldini G, Balduini W, Ballabio A, Bamber BA, Bampton ETW, Bánhegyi G, Bartholomew CR, Bassham DC, Bast RC, Batoko H, Bay BH, Beau I, Béchet DM, Begley TJ, Behl C, Behrends C, Bekri S, Bellaire B, Bendall LJ, Benetti L, Berliocchi L, Bernardi H, Bernassola F, Besteiro S, Bhatia-Kissova I, Bi X, Biard-Piechaczyk M, Blum JS, Boise LH, Bonaldo P, Boone DL, Bornhauser BC, Bortoluci KR, Bossis I, Bost F, Bourquin JP, Boya P, Boyer-Guittaut M, Bozhkov PV, Brady NR, Brancolini C, Brech A, Brenman JE, Brennand A, Bresnick EH, Brest P, Bridges D, Bristol ML, Brookes PS, Brown EJ, Brumell JH, Brunetti-Pierri N, Brunk UT, Bulman DE, Bultman SJ, Bultynck G, Burbulla LF, Bursch W, Butchar JP, Buzgariu W, Bydlowski SP, Cadwell K, Cahová M, Cai D, Cai J, Cai Q, Calabretta B, Calvo-Garrido J, Camougrand N, Campanella M, Campos-Salinas J, Candi E, Cao L, Caplan AB, Carding SR, Cardoso SM, Carew JS, Carlin CR, Carmignac V, Carneiro LAM, Carra S, Caruso RA, Casari G, Casas C, Castino R, Cebollero E, Cecconi F, Celli J, Chaachouay H, Chae HJ, Chai CY, Chan DC, Chan EY, Chang RCC, Che CM, Chen CC, Chen GC, Chen GQ, Chen M, Chen Q, Chen SSL, Chen W, Chen X, Chen X, Chen X, Chen YG, Chen Y, Chen Y, Chen YJ, Chen Z, Cheng A, Cheng CHK, Cheng Y, Cheong H, Cheong JH, Cherry S, Chess-Williams R, Cheung ZH, Chevet E, Chiang HL, Chiarelli R, Chiba T, Chin LS, Chiou SH, Chisari FV, Cho CH, Cho DH, Choi AMK, Choi D, Choi KS, Choi ME, Chouaib S, Choubey D, Choubey V, Chu CT, Chuang TH, Chueh SH, Chun T, Chwae YJ, Chye ML, Ciarcia R, Ciriolo MR, Clague MJ, Clark RSB, Clarke PGH, Clarke R, Codogno P, Coller HA, Colombo MI, Comincini S, Condello M, Condorelli F, Cookson MR, Coombs GH, Coppens I, Corbalan R, Cossart P, Costelli P, Costes S, Coto-Montes A, Couve E, Coxon FP, Cregg JM, Crespo JL, Cronjé MJ, Cuervo AM, Cullen JJ, Czaja MJ, D'Amelio M, Darfeuille-Michaud A, Davids LM, Davies FE, De Felici M, de Groot JF, de Haan CAM, De Martino L, De Milito A, De Tata V, Debnath J, Degterev A, Dehay B, Delbridge LMD, Demarchi F, Deng YZ, Dengjel J, Dent P, Denton D, Deretic V, Desai SD, Devenish RJ, Di Gioacchino M, Di Paolo G, Di Pietro C, Díaz-Araya G, Díaz-Laviada I, Diaz-Meco MT, Diaz-Nido J, Dikic I, Dinesh-Kumar SP, Ding WX, Distelhorst CW, Diwan A, Djavaheri-Mergny M, Dokudovskaya S, Dong Z, Dorsey FC, Dosenko V, Dowling JJ, Doxsey S, Dreux M, Drew ME, Duan Q, Duchosal MA, Duff K, Dugail I, Durbeej M, Duszenko M, Edelstein CL, Edinger AL, Egea G, Eichinger L, Eissa NT, Ekmekcioglu S, El-Deiry WS, Elazar Z, Elgendy M, Ellerby LM, Eng KE, Engelbrecht AM, Engelender S, Erenpreisa J, Escalante R, Esclatine A, Eskelinen EL, Espert L, Espina V, Fan H, Fan J, Fan QW, Fan Z, Fang S, Fang Y, Fanto M, Fanzani A, Farkas T, Farré JC, Faure M, Fechheimer M, Feng CG, Feng J, Feng Q, Feng Y, Fésüs L, Feuer R, Figueiredo-Pereira ME, Fimia GM, Fingar DC, Finkbeiner S, Finkel T, Finley KD, Fiorito F, Fisher EA, Fisher PB, Flajolet M, Florez-McClure ML, Florio S, Fon EA, Fornai F, Fortunato F, Fotedar R, Fowler DH, Fox HS, Franco R, Frankel LB, Fransen M, Fuentes JM, Fueyo J, Fujii J, Fujisaki K, Fujita E, Fukuda M, Furukawa RH, Gaestel M, Gailly P, Gajewska M, Galliot B, Galy V, Ganesh S, Ganetzky B, Ganley IG, Gao FB, Gao GF, Gao J, Garcia L, Garcia-Manero G, Garcia-Marcos M, Garmyn M, Gartel AL, Gatti E, Gautel M, Gawriluk TR, Gegg ME, Geng J, Germain M, Gestwicki JE, Gewirtz DA, Ghavami S, Ghosh P, Giammarioli AM, Giatromanolaki AN, Gibson SB, Gilkerson RW, Ginger ML, Ginsberg HN, Golab J, Goligorsky MS, Golstein P, Gomez-Manzano C, Goncu E, Gongora C, Gonzalez CD, Gonzalez R, González-Estévez C, González-Polo RA, Gonzalez-Rey E, Gorbunov NV, Gorski S, Goruppi S, Gottlieb RA, Gozuacik D, Granato GE, Grant GD, Green KN, Gregorc A, Gros F, Grose C, Grunt TW, Gual P, Guan JL, Guan KL, Guichard SM, Gukovskaya AS, Gukovsky I, Gunst J, Gustafsson AB, Halayko AJ, Hale AN, Halonen SK, Hamasaki M, Han F, Han T, Hancock MK, Hansen M, Harada H, Harada M, Hardt SE, Harper JW, Harris AL, Harris J, Harris SD, Hashimoto M, Haspel JA, Hayashi SI, Hazelhurst LA, He C, He YW, Hébert MJ, Heidenreich KA, Helfrich MH, Helgason GV, Henske EP, Herman B, Herman PK, Hetz C, Hilfiker S, Hill JA, Hocking LJ, Hofman P, Hofmann TG, Höhfeld J, Holyoake TL, Hong MH, Hood DA, Hotamisligil GS, Houwerzijl EJ, Høyer-Hansen M, Hu B, Hu CAA, Hu HM, Hua Y, Huang C, Huang J, Huang S, Huang WP, Huber TB, Huh WK, Hung TH, Hupp TR, Hur GM, Hurley JB, Hussain SNA, Hussey PJ, Hwang JJ, Hwang S, Ichihara A, Ilkhanizadeh S, Inoki K, Into T, Iovane V, Iovanna JL, Ip NY, Isaka Y, Ishida H, Isidoro C, Isobe KI, Iwasaki A, Izquierdo M, Izumi Y, Jaakkola PM, Jäättelä M, Jackson GR, Jackson WT, Janji B, Jendrach M, Jeon JH, Jeung EB, Jiang H, Jiang H, Jiang JX, Jiang M, Jiang Q, Jiang X, Jiang X, Jiménez A, Jin M, Jin S, Joe CO, Johansen T, Johnson DE, Johnson GVW, Jones NL, Joseph B, Joseph SK, Joubert AM, Juhász G, Juillerat-Jeanneret L, Jung CH, Jung YK, Kaarniranta K, Kaasik A, Kabuta T, Kadowaki M, Kagedal K, Kamada Y, Kaminskyy VO, Kampinga HH, Kanamori H, Kang C, Kang KB, Kang KI, Kang R, Kang YA, Kanki T, Kanneganti TD, Kanno H, Kanthasamy AG, Kanthasamy A, Karantza V, Kaushal GP, Kaushik S, Kawazoe Y, Ke PY, Kehrl JH, Kelekar A, Kerkhoff C, Kessel DH, Khalil H, Kiel JAKW, Kiger AA, Kihara A, Kim DR, Kim DH, Kim DH, Kim EK, Kim HR, Kim JS, Kim JH, Kim JC, Kim JK, Kim PK, Kim SW, Kim YS, Kim Y, Kimchi A, Kimmelman AC, King JS, Kinsella TJ, Kirkin V, Kirshenbaum LA, Kitamoto K, Kitazato K, Klein L, Klimecki WT, Klucken J, Knecht E, Ko BCB, Koch JC, Koga H, Koh JY, Koh YH, Koike M, Komatsu M, Kominami E, Kong HJ, Kong WJ, Korolchuk VI, Kotake Y, Koukourakis MI, Kouri Flores JB, Kovács AL, Kraft C, Krainc D, Krämer H, Kretz-Remy C, Krichevsky AM, Kroemer G, Krüger R, Krut O, Ktistakis NT, Kuan CY, Kucharczyk R, Kumar A, Kumar R, Kumar S, Kundu M, Kung HJ, Kurz T, Kwon HJ, La Spada AR, Lafont F, Lamark T, Landry J, Lane JD, Lapaquette P, Laporte JF, László L, Lavandero S, Lavoie JN, Layfield R, Lazo PA, Le W, Le Cam L, Ledbetter DJ, Lee AJX, Lee BW, Lee GM, Lee J, Lee JH, Lee M, Lee MS, Lee SH, Leeuwenburgh C, Legembre P, Legouis R, Lehmann M, Lei HY, Lei QY, Leib DA, Leiro J, Lemasters JJ, Lemoine A, Lesniak MS, Lev D, Levenson VV, Levine B, Levy E, Li F, Li JL, Li L, Li S, Li W, Li XJ, Li YB, Li YP, Liang C, Liang Q, Liao YF, Liberski PP, Lieberman A, Lim HJ, Lim KL, Lim K, Lin CF, Lin FC, Lin J, Lin JD, Lin K, Lin WW, Lin WC, Lin YL, Linden R, Lingor P, Lippincott-Schwartz J, Lisanti MP, Liton PB, Liu B, Liu CF, Liu K, Liu L, Liu QA, Liu W, Liu YC, Liu Y, Lockshin RA, Lok CN, Lonial S, Loos B, Lopez-Berestein G, López-Otín C, Lossi L, Lotze MT, Lőw P, Lu B, Lu B, Lu B, Lu Z, Luciano F, Lukacs NW, Lund AH, Lynch-Day MA, Ma Y, Macian F, MacKeigan JP, Macleod KF, Madeo F, Maiuri L, Maiuri MC, Malagoli D, Malicdan MCV, Malorni W, Man N, Mandelkow EM, Manon S, Manov I, Mao K, Mao X, Mao Z, Marambaud P, Marazziti D, Marcel YL, Marchbank K, Marchetti P, Marciniak SJ, Marcondes M, Mardi M, Marfe G, Mariño G, Markaki M, Marten MR, Martin SJ, Martinand-Mari C, Martinet W, Martinez-Vicente M, Masini M, Matarrese P, Matsuo S, Matteoni R, Mayer A, Mazure NM, McConkey DJ, McConnell MJ, McDermott C, McDonald C, McInerney GM, McKenna SL, McLaughlin B, McLean PJ, McMaster CR, McQuibban GA, Meijer AJ, Meisler MH, Meléndez A, Melia TJ, Melino G, Mena MA, Menendez JA, Menna-Barreto RFS, Menon MB, Menzies FM, Mercer CA, Merighi A, Merry DE, Meschini S, Meyer CG, Meyer TF, Miao CY, Miao JY, Michels PAM, Michiels C, Mijaljica D, Milojkovic A, Minucci S, Miracco C, Miranti CK, Mitroulis I, Miyazawa K, Mizushima N, Mograbi B, Mohseni S, Molero X, Mollereau B, Mollinedo F, Momoi T, Monastyrska I, Monick MM, Monteiro MJ, Moore MN, Mora R, Moreau K, Moreira PI, Moriyasu Y, Moscat J, Mostowy S, Mottram JC, Motyl T, Moussa CEH, Müller S, Muller S, Münger K, Münz C, Murphy LO, Murphy ME, Musarò A, Mysorekar I, Nagata E, Nagata K, Nahimana A, Nair U, Nakagawa T, Nakahira K, Nakano H, Nakatogawa H, Nanjundan M, Naqvi NI, Narendra DP, Narita M, Navarro M, Nawrocki ST, Nazarko TY, Nemchenko A, Netea MG, Neufeld TP, Ney PA, Nezis IP, Nguyen HP, Nie D, Nishino I, Nislow C, Nixon RA, Noda T, Noegel AA, Nogalska A, Noguchi S, Notterpek L, Novak I, Nozaki T, Nukina N, Nürnberger T, Nyfeler B, Obara K, Oberley TD, Oddo S, Ogawa M, Ohashi T, Okamoto K, Oleinick NL, Oliver FJ, Olsen LJ, Olsson S, Opota O, Osborne TF, Ostrander GK, Otsu K, Ou JHJ, Ouimet M, Overholtzer M, Ozpolat B, Paganetti P, Pagnini U, Pallet N, Palmer GE, Palumbo C, Pan T, Panaretakis T, Pandey UB, Papackova Z, Papassideri I, Paris I, Park J, Park OK, Parys JB, Parzych KR, Patschan S, Patterson C, Pattingre S, Pawelek JM, Peng J, Perlmutter DH, Perrotta I, Perry G, Pervaiz S, Peter M, Peters GJ, Petersen M, Petrovski G, Phang JM, Piacentini M, Pierre P, Pierrefite-Carle V, Pierron G, Pinkas-Kramarski R, Piras A, Piri N, Platanias LC, Pöggeler S, Poirot M, Poletti A, Poüs C, Pozuelo-Rubio M, Prætorius-Ibba M, Prasad A, Prescott M, Priault M, Produit-Zengaffinen N, Progulske-Fox A, Proikas-Cezanne T, Przedborski S, Przyklenk K, Puertollano R, Puyal J, Qian SB, Qin L, Qin ZH, Quaggin SE, Raben N, Rabinowich H, Rabkin SW, Rahman I, Rami A, Ramm G, Randall G, Randow F, Rao VA, Rathmell JC, Ravikumar B, Ray SK, Reed BH, Reed JC, Reggiori F, Régnier-Vigouroux A, Reichert AS, Reiners 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LS, Terman A, Tettamanti G, Thevissen K, Thompson CB, Thorburn A, Thumm M, Tian F, Tian Y, Tocchini-Valentini G, Tolkovsky AM, Tomino Y, Tönges L, Tooze SA, Tournier C, Tower J, Towns R, Trajkovic V, Travassos LH, Tsai TF, Tschan MP, Tsubata T, Tsung A, Turk B, Turner LS, Tyagi SC, Uchiyama Y, Ueno T, Umekawa M, Umemiya-Shirafuji R, Unni VK, Vaccaro MI, Valente EM, Van den Berghe G, van der Klei IJ, van Doorn W, van Dyk LF, van Egmond M, van Grunsven LA, Vandenabeele P, Vandenberghe WP, Vanhorebeek I, Vaquero EC, Velasco G, Vellai T, Vicencio JM, Vierstra RD, Vila M, Vindis C, Viola G, Viscomi MT, Voitsekhovskaja OV, von Haefen C, Votruba M, Wada K, Wade-Martins R, Walker CL, Walsh CM, Walter J, Wan XB, Wang A, Wang C, Wang D, Wang F, Wang F, Wang G, Wang H, Wang HG, Wang HD, Wang J, Wang K, Wang M, Wang RC, Wang X, Wang X, Wang YJ, Wang Y, Wang Z, Wang ZC, Wang Z, Wansink DG, Ward DM, Watada H, Waters SL, Webster P, Wei L, Weihl CC, Weiss WA, Welford SM, Wen LP, Whitehouse CA, Whitton JL, Whitworth AJ, Wileman T, Wiley JW, Wilkinson S, Willbold D, Williams RL, Williamson PR, Wouters BG, Wu C, Wu DC, Wu WKK, Wyttenbach A, Xavier RJ, Xi Z, Xia P, Xiao G, Xie Z, Xie Z, Xu DZ, Xu J, Xu L, Xu X, Yamamoto A, Yamamoto A, Yamashina S, Yamashita M, Yan X, Yanagida M, Yang DS, Yang E, Yang JM, Yang SY, Yang W, Yang WY, Yang Z, Yao MC, Yao TP, Yeganeh B, Yen WL, Yin JJ, Yin XM, Yoo OJ, Yoon G, Yoon SY, Yorimitsu T, Yoshikawa Y, Yoshimori T, Yoshimoto K, You HJ, Youle RJ, Younes A, Yu L, Yu L, Yu SW, Yu WH, Yuan ZM, Yue Z, Yun CH, Yuzaki M, Zabirnyk O, Silva-Zacarin E, Zacks D, Zacksenhaus E, Zaffaroni N, Zakeri Z, Zeh HJ, Zeitlin SO, Zhang H, Zhang HL, Zhang J, Zhang JP, Zhang L, Zhang L, Zhang MY, Zhang XD, Zhao M, Zhao YF, Zhao Y, Zhao ZJ, Zheng X, Zhivotovsky B, Zhong Q, Zhou CZ, Zhu C, Zhu WG, Zhu XF, Zhu X, Zhu Y, Zoladek T, Zong WX, Zorzano A, Zschocke J, Zuckerbraun B. Guidelines for the use and interpretation of assays for monitoring autophagy. Autophagy 2012; 8:445-544. [PMID: 22966490 PMCID: PMC3404883 DOI: 10.4161/auto.19496] [Citation(s) in RCA: 2733] [Impact Index Per Article: 227.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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Affiliation(s)
- Daniel J Klionsky
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
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Abstract
Although resistance to chloroquine (CQ) has relegated it from modern chemotherapeutic strategies to treat Plasmodium falciparum malaria, new evidence suggests that higher doses of the drug may exert a different killing mechanism and offers this drug a new lease of life. Whereas the established antimalarial mechanisms of CQ are usually associated with nanomolar levels of the drug, micromolar levels of CQ trigger a distinct cell death pathway involving the permeabilization of the digestive vacuole of the parasite and a release of hydrolytic enzymes. In this paper, we propose that this pathway is a promising antimalarial strategy and suggest that revising the CQ treatment regimen may elevate blood drug levels to trigger this pathway without increasing the incidence of adverse reactions.
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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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Dunn LA, Tan KSW, Vanelle P, Juspin T, Crozet MD, Terme T, Upcroft P, Upcroft JA. Development of metronidazole-resistant lines of Blastocystis sp. Parasitol Res 2012; 111:441-50. [PMID: 22362365 DOI: 10.1007/s00436-012-2860-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Accepted: 02/07/2012] [Indexed: 01/22/2023]
Abstract
Metronidazole (MTR) is frequently used for the treatment of Blastocystis infections, but with variable effectiveness, and often with treatment failures as a possible result of drug resistance. We have developed two Blastocystis MTR-resistant (MTR(R)) subtype 4 WR1 lines (WR1-M4 and WR1-M5), with variable susceptibility to a panel of anti-protozoal agents including various 5-nitroimidazoles, nitazoxanide and furazolidone. WR1-M4 and WR1-M5 were developed and assessed over an 18-month period and displayed persistent MTR resistance, being more than 2.5-fold less susceptible to MTR than the parent isolate. The MTR(R) lines grew with a similar g time to WR1, but were morphologically less consistent with a mixture of size. All Blastocystis isolates and the MTR(R) lines were most susceptible to the 5-nitroimidazole drug ronidazole. WR1-M5 was apparently cross-resistant to satranidazole and furazolidone, and WR1-M4 was cross-resistant to nitazoxanide. These MTR(R) lines now provide a valuable tool for the continued assessment of the efficacy and mechanism of action of new and established drugs against a range of Blastocystis sp. subtypes, in order to identify a universally effective drug and to facilitate understanding of the mechanisms of drug action and resistance in Blastocystis.
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Affiliation(s)
- L A Dunn
- Queensland Institute of Medical Research, PO Royal Brisbane Hospital, 4029, Herston, Queensland, Australia.
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29
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Abstract
Blastocystis is an enteric protistan parasite of uncertain clinical relevance. Recent studies indicate that the parasite is a species complex and humans are potentially hosts to nine Blastocystis subtypes, most of which are zoonotic. Subtype 3 is the most common in prevalence studies, followed by subtype 1. Laboratory diagnosis is challenging; the currently recommended diagnostic approach is trichrome staining of direct smears coupled with stool culture. Polymerase chain reaction testing from stools or culture is useful for determining Blastocystis subtype information. The controversial pathogenesis of Blastocystis is attributed to subtype variations in virulence; although current studies seem to support this idea, evidence suggests other factors also contribute to the clinical outcome of the infection. Clinical signs and symptoms of blastocystosis include abdominal pain, diarrhea, bloating, and flatulence. Extraintestinal manifestations, predominantly cutaneous, also were reported. In vitro and animal studies shed new light on the pathobiology of Blastocystis.
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Affiliation(s)
- Kevin S W Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117597, Singapore,
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30
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Denoeud F, Roussel M, Noel B, Wawrzyniak I, Da Silva C, Diogon M, Viscogliosi E, Brochier-Armanet C, Couloux A, Poulain J, Segurens B, Anthouard V, Texier C, Blot N, Poirier P, Ng GC, Tan KSW, Artiguenave F, Jaillon O, Aury JM, Delbac F, Wincker P, Vivarès CP, El Alaoui H. Genome sequence of the stramenopile Blastocystis, a human anaerobic parasite. Genome Biol 2011; 12:R29. [PMID: 21439036 PMCID: PMC3129679 DOI: 10.1186/gb-2011-12-3-r29] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 01/04/2011] [Accepted: 03/25/2011] [Indexed: 01/28/2023] Open
Abstract
Background Blastocystis is a highly prevalent anaerobic eukaryotic parasite of humans and animals that is associated with various gastrointestinal and extraintestinal disorders. Epidemiological studies have identified different subtypes but no one subtype has been definitively correlated with disease. Results Here we report the 18.8 Mb genome sequence of a Blastocystis subtype 7 isolate, which is the smallest stramenopile genome sequenced to date. The genome is highly compact and contains intriguing rearrangements. Comparisons with other available stramenopile genomes (plant pathogenic oomycete and diatom genomes) revealed effector proteins potentially involved in the adaptation to the intestinal environment, which were likely acquired via horizontal gene transfer. Moreover, Blastocystis living in anaerobic conditions harbors mitochondria-like organelles. An incomplete oxidative phosphorylation chain, a partial Krebs cycle, amino acid and fatty acid metabolisms and an iron-sulfur cluster assembly are all predicted to occur in these organelles. Predicted secretory proteins possess putative activities that may alter host physiology, such as proteases, protease-inhibitors, immunophilins and glycosyltransferases. This parasite also possesses the enzymatic machinery to tolerate oxidative bursts resulting from its own metabolism or induced by the host immune system. Conclusions This study provides insights into the genome architecture of this unusual stramenopile. It also proposes candidate genes with which to study the physiopathology of this parasite and thus may lead to further investigations into Blastocystis-host interactions.
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Affiliation(s)
- France Denoeud
- Genoscope (CEA) and CNRS UMR 8030, Université d'Evry, 2 rue Gaston Crémieux, 91057 Evry, France
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Mills JP, Qie L, Dao M, Tan KSW, Lim CT, Suresh S. Continuous force-displacement relationships for the human red blood cell at different erythrocytic developmental stages ofPlasmodium falciparummalaria parasite. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-844-y7.8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTPrior work involving either aspiration of infected cells into micropipette under suction pressure or deformation in laminar shear flow revealed that the malaria parasitePlasmodium (P.) falciparumcould result in significant stiffening of infected human red blood cells (RBCs). In this paper, we present optical tweezers studies of progressive changes to nonlinear mechanical response of infected RBCs at different developmental stages ofP. falciparum.From early ring stage to late trophozoite and schizont stages, up to an order of magnitude increase in shear modulus was found under controlled mechanical loading by combining experiments with three-dimensional computational simulations. These results provide novel approaches to study changes in mechanical deformability in the advanced stages of parasite development in the erythrocyte, and suggest a significantly greater stiffening of the red blood cell due toP. falciparuminvasion than that considered from previous studies.
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Xiong W, Ong SH, Lim JH, Weng Chiong Foong K, Liu J, Racoceanu D, Chong AGL, Tan KSW. Automatic Area Classification in Peripheral Blood Smears. IEEE Trans Biomed Eng 2010; 57:1982-90. [DOI: 10.1109/tbme.2010.2043841] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
Previous studies have demonstrated that colony forms of Blastocystis undergo cell death with numerous membrane-bound vesicles containing organelles located within the central vacuole, resembling morphological features of autophagy. In this study, we investigated whether Blastocystis underwent autophagy upon amino acid starvation and rapamycin treatment. Concurrently, we provide new insight into a possible function of the central vacuole. The use of the autophagy marker monodansylcadaverine, and the autophagy inhibitors3-methyladenine and wortmannin, showed the existence of autophagy in amino-acid-starved and rapamycin-treated Blastocystis. Confocal microscopy and transmission electron microscopy studies also showed morphological changes that were suggestive of autophagy. The unusually large size of the autophagic compartments within the parasite central vacuole was found to be unique in Blastocystis. In addition, autophagy was found to be triggered when cells were exposed to the cytotoxic antibody mAb 1D5, and autophagy was intensified in the presence of the caspase inhibitor zVAD.fmk. Taken together, our results suggest that the core machinery for autophagy is conserved in Blastocystis, and that it plays an important role in the starvation response and cell death of the parasite.
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Affiliation(s)
- Jing Yin
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore
| | - Angeline J. J. Ye
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore
| | - Kevin S. W. Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore
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Mirza H, Tan KSW. Blastocystis exhibits inter- and intra-subtype variation in cysteine protease activity. Parasitol Res 2008; 104:355-61. [PMID: 18846388 DOI: 10.1007/s00436-008-1203-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Accepted: 09/12/2008] [Indexed: 12/11/2022]
Abstract
Blastocystis is an enteric protistan parasite of zoonotic potential and poorly understood pathogenesis. We have previously reported that Blastocystis cysteine proteases can degrade human secretory IgA and are also responsible for the induction of IL-8 response in colonic epithelial cells in vitro. Differences in virulence between Blastocystis subtypes have been reported recently in both animal models and clinical studies, although cellular mechanisms for these differences are currently unknown. Parasites such as Giardia intestinalis and Entamoeba histolytica have distinct virulent and non-virulent strains which may be attributable to variations in their cysteine proteases. In the present study, variations in cysteine protease activity was observed between avian (subtype 7) and rodent (subtype 4) isolates of Blastocystis with avian isolates exhibiting approximately two times higher peak cysteine protease activity than rodent isolates. Cysteine protease activity and parasite cell size varied over time within cultures of the same isolate. An association between parasite cell size and protease activity was observed.
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Affiliation(s)
- Haris Mirza
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Kent Ridge 117597, Singapore
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Lantsman Y, Tan KSW, Morada M, Yarlett N. Biochemical characterization of a mitochondrial-like organelle from Blastocystis sp. subtype 7. Microbiology (Reading) 2008; 154:2757-2766. [PMID: 18757809 DOI: 10.1099/mic.0.2008/017897-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A mitochondrion-like organelle (MLO) was isolated from isotonic homogenates of Blastocystis. The organelle sedimented at 5000 g for 10 min, and had an isopycnic density in sucrose of 1.2 g ml(-1). Biochemical characterization enabled the demonstration of several key enzymes that allowed the construction of a metabolic pathway consisting of an incomplete Krebs cycle linked to the oxygen-sensitive enzymes pyruvate : NADP(+) oxidoreductase (PNO), acetate : succinate CoA transferase (ASCT) and succinate thiokinase (STK), which cumulatively are responsible for recycling CoA and generating ATP. The organelle differs from typical aerobic mitochondria in possessing an oxygen-sensitive PNO that can use FAD(+) or FMN(+) as electron acceptor but is inactive with NAD(+), Spinacia oleracea ferredoxin or Clostridium pasteurianum ferredoxin. A gene with 77 % sequence similarity to the PNO mitochondrion precursor cluster from Euglena gracilis sp[Q941N5] was identified in the Blastocystis genome database. A second cluster with 56 % sequence similarity to the pyruvate : ferredoxin oxidoreductase (PFOR) from Trichomonas vaginalis was also identified, which is in agreement with the concept that the PNO gene arose through the fusion of a eubacterial gene for PFOR with the gene for NADPH : cytochrome p450 reductase. Hydrogenase activity was not detected under the conditions used in this study. The Blastocystis oranelle therefore demonstrates significant biochemical differences from traditional mitochondria and hydrogenosomes, but possesses features of both. Based upon the results of this study, the Blastocystis organelle falls into the category of a MLO.
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Affiliation(s)
- Yelena Lantsman
- Haskins Laboratories, Pace University, New York, NY 10038, USA
| | - Kevin S W Tan
- Laboratory of Molecular and Cellular Parasitology and Infectious Disease Programme, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 117597, Singapore
| | - Mary Morada
- Haskins Laboratories, Pace University, New York, NY 10038, USA
| | - Nigel Yarlett
- Department of Chemistry and Physical Sciences, Pace University, New York, NY 10038, USA.,Haskins Laboratories, Pace University, New York, NY 10038, USA
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Abstract
SUMMARY Blastocystis is an unusual enteric protozoan parasite of humans and many animals. It has a worldwide distribution and is often the most commonly isolated organism in parasitological surveys. The parasite has been described since the early 1900s, but only in the last decade or so have there been significant advances in our understanding of Blastocystis biology. However, the pleomorphic nature of the parasite and the lack of standardization in techniques have led to confusion and, in some cases, misinterpretation of data. This has hindered laboratory diagnosis and efforts to understand its mode of reproduction, life cycle, prevalence, and pathogenesis. Accumulating epidemiological, in vivo, and in vitro data strongly suggest that Blastocystis is a pathogen. Many genotypes exist in nature, and recent observations indicate that humans are, in reality, hosts to numerous zoonotic genotypes. Such genetic diversity has led to a suggestion that previously conflicting observations on the pathogenesis of Blastocystis are due to pathogenic and nonpathogenic genotypes. Recent epidemiological, animal infection, and in vitro host-Blastocystis interaction studies suggest that this may indeed be the case. This review focuses on such recent advances and also provides updates on laboratory and clinical aspects of Blastocystis spp.
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Affiliation(s)
- Kevin S W Tan
- Department of Microbiology, Laboratory of Molecular and Cellular Parasitology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore.
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Abstract
Four Blastocystis isolates from cockroaches were established and these isolates were morphologically confirmed as Blastocystis organisms by light and/or electron microscopy. As these isolates were morphologically indistinguishable from Blastocystis isolated from other animals, phylogenetic analyses were conducted using their small subunit ribosomal RNA genes. A analyses of these sequences with previously reported ones that had been classified into nine Blastocystis clades indicated the presence of a new clade that comprised only Blastocystis organisms from cockroaches (clade X). A clade comprised of amphibian and reptilian Blastocystis organisms (clade IX) was located at the basal position of the Blastocystis tree together with the common ancestor of Proteromonas and Protoopalina, clade X emerged after the divergences of these two basal clades and its branching position was clearly supported by bootstrap analysis.
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Affiliation(s)
- Hisao Yoshikawa
- Department of Biological Sciences, Faculty of Science, Nara Women's University, Kitauoya-Nishimachi, Nara 630-8506, Japan.
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Stensvold CR, Suresh GK, Tan KSW, Thompson RCA, Traub RJ, Viscogliosi E, Yoshikawa H, Clark CG. Terminology for Blastocystis subtypes--a consensus. Trends Parasitol 2007; 23:93-6. [PMID: 17241816 DOI: 10.1016/j.pt.2007.01.004] [Citation(s) in RCA: 271] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 11/15/2006] [Accepted: 01/12/2007] [Indexed: 11/17/2022]
Abstract
Blastocystis is a ubiquitous enteric protistan parasite that has extensive genetic diversity and infects humans and many other animals. Distinct molecular methodologies developed to detect variation and obtain information about transmission patterns and clinical importance have resulted in a confusing array of terminologies for the identification and designation of Blastocystis subtypes. In this article, we propose a standardization of Blastocystis terminology to improve communication and correlate research results. Based primarily on published small-subunit ribosomal RNA gene analyses, we propose that all mammalian and avian isolates should be designated Blastocystis sp. and assigned to one of nine subtypes.
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Affiliation(s)
- C Rune Stensvold
- Laboratory of Parasitology, Department of Bacteriology, Mycology and Parasitology, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark
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Sio SWS, Sun W, Kumar S, Bin WZ, Tan SS, Ong SH, Kikuchi H, Oshima Y, Tan KSW. MalariaCount: An image analysis-based program for the accurate determination of parasitemia. J Microbiol Methods 2007; 68:11-8. [PMID: 16837087 DOI: 10.1016/j.mimet.2006.05.017] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Revised: 05/29/2006] [Accepted: 05/31/2006] [Indexed: 11/23/2022]
Abstract
Malaria is a serious global health problem and rapid, precise determination of parasitemia is necessary for malaria research and in clinical settings. Manual counting by light microscopy is the most widely used technique for parasitemia determination but it is a time-consuming and laborious process. The aim of our study was to develop an automated image analysis-based system for the rapid and accurate determination of parasitemia. We have developed, for the first time, a software, MalariaCount, that automatically generates parasitemias from images of Giemsa-stained blood smears. The potential application and robustness of MalariaCount was tested in normal and drug-treated in vitro cultures of Plasmodium falciparum. The results showed a tight correlation between MalariaCount and manual count parasitemia values. These findings suggest that MalariaCount can potentially be used as a tool to provide rapid and accurate determination of parasitemia in research laboratories where frequent, large-scale, efficient determination of parasitemia is required.
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Affiliation(s)
- Selena W S Sio
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Puthia MK, Sio SWS, Lu J, Tan KSW. Blastocystis ratti induces contact-independent apoptosis, F-actin rearrangement, and barrier function disruption in IEC-6 cells. Infect Immun 2006; 74:4114-23. [PMID: 16790785 PMCID: PMC1489721 DOI: 10.1128/iai.00328-06] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Blastocystis is an enteric protozoan purportedly associated with numerous clinical cases of diarrhea, flatulence, vomiting, and other gastrointestinal symptoms. Despite new knowledge of Blastocystis cell biology, genetic diversity, and epidemiology, its pathogenic potential remains controversial. Numerous clinical and epidemiological studies either implicate or exonerate the parasite as a cause of intestinal disease. Therefore, the aim of this study was to investigate the pathogenic potential of Blastocystis by studying the interactions of Blastocystis ratti WR1, an isolate of zoonotic potential, with a nontransformed rat intestinal epithelial cell line, IEC-6. Here, we report that B. ratti WR1 induces apoptosis in IEC-6 cells in a contact-independent manner. Furthermore, we found that B. ratti WR1 rearranges F-actin distribution, decreases transepithelial resistance, and increases epithelial permeability in IEC-6 cell monolayers. In addition, we found that the effects of B. ratti on transepithelial electrical resistance and epithelial permeability were significantly abrogated by treatment with metronidazole, an antiprotozoal drug. Our results suggest for the first time that Blastocystis-induced apoptosis in host cells and altered epithelial barrier function might play an important role in the pathogenesis of Blastocystis infections and that metronidazole has therapeutic potential in alleviating symptoms associated with Blastocystis.
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Affiliation(s)
- Manoj K Puthia
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117597, Singapore
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Li A, Mansoor AH, Tan KSW, Lim CT. Observations on the internal and surface morphology of malaria infected blood cells using optical and atomic force microscopy. J Microbiol Methods 2006; 66:434-9. [PMID: 16519955 DOI: 10.1016/j.mimet.2006.01.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2005] [Revised: 01/16/2006] [Accepted: 01/23/2006] [Indexed: 11/30/2022]
Abstract
We describe a simple and fast method to probe the morphological changes on the exterior and interior of a malaria infected erythrocyte at different stages of parasite development. This involves the imaging and scanning of Giemsa stained malaria infected erythrocytes using optical microscopy and atomic force microscopy, respectively.
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Affiliation(s)
- Ang Li
- Nano Biomechanics Laboratory, Division of Bioengineering and Department of Mechanical Engineering, National University of Singapore, Singapore 117576
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Abstract
Parasite-derived proteases are important for the parasite life cycle and the pathogenesis of the disease they produce. Proteases of intestinal protozoan parasite Blastocystis hominis were studied for the first time with azocasein assays and gelatin SDS-PAGE analysis. Parasitic lysates were found to have high protease activity and nine protease bands of low (20-33 kDa) and high (44-75 kDa) molecular weights were reported. Proteases were found to be pH-dependent and highest proteolytic activity was observed at neutral pH. Inhibition studies showed that B. hominis isolate B, like many other protozoan parasites, contains mainly cysteine proteases.
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Affiliation(s)
- Selena W S Sio
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117597, Singapore
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Abstract
mRNA maturation in Trypanosoma brucei depends upon trans splicing, and variations in trans-splicing efficiency could be an important step in controlling the levels of individual mRNAs. RNA splicing requires specific sequence elements, including conserved 5' splice sites, branch points, pyrimidine-rich regions [poly(Y) tracts], 3' splice sites (3'SS), and sometimes enhancer elements. To analyze sequence requirements for efficient trans splicing in the poly(Y) tract and around the 3'SS, we constructed a luciferase-beta-galactosidase double-reporter system. By testing approximately 90 sequences, we demonstrated that the optimum poly(Y) tract length is approximately 25 nucleotides. Interspersing a purely uridine-containing poly(Y) tract with cytidine resulted in increased trans-splicing efficiency, whereas purines led to a large decrease. The position of the poly(Y) tract relative to the 3'SS is important, and an AC dinucleotide at positions -3 and -4 can lead to a 20-fold decrease in trans splicing. However, efficient trans splicing can be restored by inserting a second AG dinucleotide downstream, which does not function as a splice site but may aid in recruitment of the splicing machinery. These findings should assist in the development of improved algorithms for computationally identifying a 3'SS and help to discriminate noncoding open reading frames from true genes in current efforts to annotate the T. brucei genome.
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Affiliation(s)
- T Nicolai Siegel
- Laboratory of Molecular Parasitology, Box 185, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
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Tan KSW, Nasirudeen AMA. Protozoan programmed cell death – insights from Blastocystis deathstyles. Trends Parasitol 2005; 21:547-50. [PMID: 16223601 DOI: 10.1016/j.pt.2005.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2005] [Revised: 08/10/2005] [Accepted: 09/28/2005] [Indexed: 10/25/2022]
Abstract
Programmed cell death (PCD) is an essential process in the growth and development of multicellular organisms. However, accumulating evidence indicates that unicellular eukaryotes can also undergo PCD with apoptosis-like features. The protozoan parasite Blastocystis hominis has been reported to exhibit both apoptotic and non-apoptotic features of PCD when exposed to a variety of stimuli. Recent observations of PCD pathways in Blastocystis suggest that this protozoan, as is the case with its multicellular counterparts, possesses complex cell-death mechanisms.
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Affiliation(s)
- Kevin S W Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117597.
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Puthia MK, Vaithilingam A, Lu J, Tan KSW. Degradation of human secretory immunoglobulin A by Blastocystis. Parasitol Res 2005; 97:386-9. [PMID: 16151742 DOI: 10.1007/s00436-005-1461-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Accepted: 06/27/2005] [Indexed: 10/25/2022]
Abstract
Microbial immunoglobulin A (IgA) proteases cleave human secretory IgA, promoting the mucosal adhesion of pathogens. To investigate if the enteric protozoan Blastocystis degrades human secretory IgA, cell lysate and conditioned medium from two species were exposed to immunoglobulin A. Secretory IgA was cleaved by both cell lysate and conditioned medium with mainly cysteine proteinase activity in B. hominis B isolate and aspartic proteinase activity in B. ratii WR1 isolate. These findings suggest that Blastocystis proteases may play a role in parasite survival in vivo.
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Affiliation(s)
- Manoj K Puthia
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597
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Nasirudeen AMA, Tan KSW. Programmed cell death in Blastocystis hominis occurs independently of caspase and mitochondrial pathways. Biochimie 2005; 87:489-97. [PMID: 15913879 DOI: 10.1016/j.biochi.2005.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2004] [Revised: 02/18/2005] [Accepted: 03/17/2005] [Indexed: 10/25/2022]
Abstract
We demonstrated previously that a cytotoxic monoclonal antibody (MAb) 1D5 elicits a programmed cell death (PCD) response in Blastocystis hominis and showed that caspase-3-like protease influences but is not essential for PCD in MAb 1D5-treated B. hominis. We also showed that mitochondrial dysregulation played a role in cell death. In the current study, we further analyzed the signaling pathways involved in PCD mediated by MAb 1D5. B. hominis cells were treated with MAb 1D5 or control MAb 5, either with or without pretreatment with a pan-caspase inhibitor, zVAD.fmk, and/or a mitochondrial transition pore blocker, cyclosporine A (CA). Flow cytometric examination of cell size, mitochondrial membrane potential (delta psi(m)), caspase activation and in situ DNA fragmentation showed that zVAD.fmk and CA, used independently or in combination, failed to inhibit MAb 1D5-mediated PCD. Interestingly, cell exposure to either inhibitor resulted in partial inhibition of DNA fragmentation while combined exposure of cells to inhibitors abolished DNA fragmentation completely. This study sheds new light on the conserved nature of PCD pathways in parasitic protozoa and is also the first report describing caspase- and mitochondria-independent cell death pathways in a protozoan parasite.
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Affiliation(s)
- A M A Nasirudeen
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Faculty of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117597, Singapore
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47
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Abstract
Among the waterborne protozoan parasites of medical and veterinary importance, Blastocystis is perhaps one of the less well-understood. However, in recent years, there has been a surge of interest in the organism, fueled in part by the possible association of Blastocystis infection with intestinal disorders, and its unusual taxonomic affiliations. Although there is information on the parasite's morphology, taxonomy and mode of transmission, its pathogenicity, life cycle, and function of certain organelles continue to baffle investigators. The clinical relevance of Blastocystis will be better answered once an animal model is found. Blastocystis infections have a worldwide distribution but prevalence is highest in areas with poor hygiene and deficient sanitation services and facilities. Application of modern molecular tools has advanced knowledge of the organism's genetic diversity, taxonomy and zoonotic potential.
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Affiliation(s)
- Kevin S W Tan
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Faculty of Medicine, National University of Singapore, 5 Science Drive 2, S 117597 Singapore, Singapore.
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Nasirudeen AMA, Tan KSW. Caspase-3-like protease influences but is not essential for DNA fragmentation in Blastocystis undergoing apoptosis. Eur J Cell Biol 2005; 83:477-82. [PMID: 15540464 DOI: 10.1078/0171-9335-00411] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Blastocystis hominis undergo apoptosis after treatment with a cytotoxic monoclonal antibody (MAb), 1D5, by mechanisms that are not fully understood, although our previous study demonstrated that caspase-3-like protease activity is involved. To elucidate the mechanism of MAb 1D5-induced apoptosis, we inhibited Blastocystis caspase-3-like protease to investigate if there would be a concomitant decrease in in situ DNA fragmentation. However, MAb 1D5-induced apoptosis, evidenced by DNA fragmentation, was not completely blocked by pretreating with specific caspase-3 inhibitor, Ac-DEVD-CHO, indicating that caspase-independent apoptotic pathways might also be involved. Our results also revealed that the treatment with MAb 1D5 resulted in the loss of mitochondrial membrane potential (deltapsim), independent of Ac-DEVD-CHO pretreatment. In conclusion, this study demonstrates that MAb 1D5-induced apoptosis in B. hominis is not wholly dependent on caspase-3-like protease activity and is associated with mitochondrial dysregulation. This is the first report showing evidence for complex apoptotic pathways in a unicellular parasite.
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Affiliation(s)
- A M A Nasirudeen
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Faculty of Medicine, National University of Singapore, Singapore
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49
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Puthia MK, Tan KSW. Plasmodium falciparum: a simplified technique for obtaining singly infected erythrocytes. Parasitol Res 2004; 95:176-8. [PMID: 15616858 DOI: 10.1007/s00436-004-1266-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2004] [Accepted: 10/28/2004] [Indexed: 11/30/2022]
Abstract
We report the development of a simple technique involving 15 ml polypropylene tubes and a rotatory incubator for obtaining erythrocytes singly infected with Plasmodium falciparum. This technique will be useful for cloning of the parasite. Our finding that P. falciparum merozoite invasion is inhibited during rotation suggests that this method may also be useful for the study of parasite-erythrocyte interactions under dynamic circulatory conditions.
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Affiliation(s)
- Manoj K Puthia
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Faculty of Medicine, National University of Singapore, 5 Science Drive 2, 117597, Singapore
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50
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Nasirudeen AMA, Tan KSW. Isolation and characterization of the mitochondrion-like organelle from Blastocystis hominis. J Microbiol Methods 2004; 58:101-9. [PMID: 15177908 DOI: 10.1016/j.mimet.2004.03.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Revised: 03/06/2004] [Accepted: 03/11/2004] [Indexed: 11/18/2022]
Abstract
Blastocystis hominis in an unusual protozoan parasite of the human intestinal tract. Previous studies have described the presence of mitochondrial-like structures despite the anaerobic nature of the organism. In this study, we describe a simple and rapid technique to isolate and characterize mitochondrion-like organelles (MLO) from B. hominis. The parasite was disrupted using glass beads and the MLO were collected and purified using a sucrose gradient. Negative staining and transmission electron microscopy of the isolated organelles showed mitochondrial-like structures. B. hominis cells were stained with rhodamine 123 and MitoLight to show the presence of transmembrane potential of the MLO. DAPI staining of the cells suggested the presence of DNA in the MLO. Though brief reports have been made in literature, this study is the first to describe a technique for the isolation of the MLO from this organism. Using this technique of isolation, major metabolic functions of the organelle, their associated macromolecules and intra-mitochondrial location can be extensively studied. The role of MLO in this anaerobic protozoan can be widely investigated using this protocol.
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Affiliation(s)
- A M A Nasirudeen
- Laboratory of Molecular and Cellular Parasitology, Department of Microbiology, Faculty of Medicine, National University of Singapore, 5 Science Drive 2, 117597 Singapore
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