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Hill S, Decorso I, Nezamololama N, Babaei Z, Rafferty SP. Catalytic Differences between Flavohemoglobins of Giardia intestinalis and E. coli. Pathogens 2024; 13:480. [PMID: 38921778 DOI: 10.3390/pathogens13060480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/26/2024] [Accepted: 06/04/2024] [Indexed: 06/27/2024] Open
Abstract
The sole known heme enzyme of the parasitic protist Giardia intestinalis is a flavohemoglobin (gFlHb) that acts as a nitric oxide dioxygenase (NOD) and protects the organism from the free radical nitric oxide. To learn more about the properties of this enzyme, we measured its nitric oxide dioxygenase, NADH oxidase, and cytochrome c reductase activities and compared these to the activities of the E. coli flavohemoglobin (Hmp). The turnover number for the NOD activity of gFlHb (23 s-1) is about two-thirds of that of Hmp (34 s-1) at pH 6.5 and 37 °C. The two enzymes differ in their sensitivity towards molecules that act as heme ligands. For both gFlHb and Hmp, inhibition with miconazole, a large imidazole ligand, is adequately described by simple competitive inhibition, with KI = 10 μM and 0.27 μM for gFlHb and Hmp, respectively. Inhibition plots with the small ligand imidazole were biphasic, which is consistent with previous experiments with carbon monoxide as a probe that show that the active site of flavohemoglobins exists in two conformations. Interestingly, the largest difference is observed with nitrite, which, like imidazole, also shows a biphasic inhibition plot; however, nitrite inhibits gFlHb at sub-millimolar concentrations while Hmp is not significantly affected. NADH oxidase activity measured under aerobic conditions in the absence of nitric oxide for Hmp was more than twice the activity of gFlHb. The addition of 1 mM hydrogen peroxide in these assays stimulated the NADH oxidase activity of gFlHb but not Hmp. Both enzymes had nearly identical cytochrome c reductase activities but the extent of the contribution of indirect reduction by flavohemoglobin-generated superoxide was much lower with gFlHb (4% SOD-inhibited) than with Hmp (17% SOD-inhibited). Although the active sites of the two enzymes share the same highly conserved residues that are important for catalysis, differences in the distal ligand binding site may account for these differences in activity and sensitivity towards NOD inhibitors. The differences observed in the NADH oxidase and cytochrome c reductase assays suggest that gFlHb may have evolved to protect the protist, which lacks both superoxide dismutase and catalase, from the damaging effects of superoxide by minimizing its production and from peroxide by actively reducing it.
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Affiliation(s)
- Sarah Hill
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON K9J 7B8, Canada
| | - Isabelle Decorso
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON K9J 7B8, Canada
| | - Novin Nezamololama
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON K9J 7B8, Canada
| | - Zahra Babaei
- Department of Parasitology & Mycology, Kerman University of Medical Sciences, Kerman 76169-13555, Iran
| | - Steven Patrick Rafferty
- Environmental and Life Sciences Graduate Program, Trent University, Peterborough, ON K9J 7B8, Canada
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Zoghroban HS, Ibrahim FMK, Nasef NA, Saad AE. The impact of L-citrulline on murine intestinal cell integrity, immune response, and arginine metabolism in the face of Giardia lamblia infection. Acta Trop 2022; 237:106748. [DOI: 10.1016/j.actatropica.2022.106748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 11/06/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022]
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3
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Zhang X, Li X, Yu Y, Zhang X, Wang X, Zhang N, Chen M, Gong P, Li J. Giardia lamblia
regulates the production of proinflammatory cytokines through activating the NOD2–Rip2–ROS signaling pathway in mouse macrophages. Immunol Cell Biol 2022; 100:440-452. [DOI: 10.1111/imcb.12550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/17/2022] [Accepted: 03/31/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Xu Zhang
- Key Laboratory of Zoonosis Research Ministry of Education College of Veterinary Medicine Jilin University 5333 Xian Road Changchun Jilin 130062 China
| | - Xin Li
- Key Laboratory of Zoonosis Research Ministry of Education College of Veterinary Medicine Jilin University 5333 Xian Road Changchun Jilin 130062 China
| | - Yanhui Yu
- The Second Hospital of Jilin University Changchun Jilin 130021 China
| | - Xichen Zhang
- Key Laboratory of Zoonosis Research Ministry of Education College of Veterinary Medicine Jilin University 5333 Xian Road Changchun Jilin 130062 China
| | - Xiaocen Wang
- Key Laboratory of Zoonosis Research Ministry of Education College of Veterinary Medicine Jilin University 5333 Xian Road Changchun Jilin 130062 China
| | - Nan Zhang
- Key Laboratory of Zoonosis Research Ministry of Education College of Veterinary Medicine Jilin University 5333 Xian Road Changchun Jilin 130062 China
| | - Mengge Chen
- Key Laboratory of Zoonosis Research Ministry of Education College of Veterinary Medicine Jilin University 5333 Xian Road Changchun Jilin 130062 China
| | - Pengtao Gong
- Key Laboratory of Zoonosis Research Ministry of Education College of Veterinary Medicine Jilin University 5333 Xian Road Changchun Jilin 130062 China
| | - Jianhua Li
- Key Laboratory of Zoonosis Research Ministry of Education College of Veterinary Medicine Jilin University 5333 Xian Road Changchun Jilin 130062 China
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Rojas L, Grüttner J, Ma’ayeh S, Xu F, Svärd SG. Dual RNA Sequencing Reveals Key Events When Different Giardia Life Cycle Stages Interact With Human Intestinal Epithelial Cells In Vitro. Front Cell Infect Microbiol 2022; 12:862211. [PMID: 35573800 PMCID: PMC9094438 DOI: 10.3389/fcimb.2022.862211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 03/31/2022] [Indexed: 12/02/2022] Open
Abstract
Giardia intestinalis is a protozoan parasite causing diarrheal disease, giardiasis, after extracellular infection of humans and other mammals’ intestinal epithelial cells (IECs) of the upper small intestine. The parasite has two main life cycle stages: replicative trophozoites and transmissive cysts. Differentiating parasites (encysting cells) and trophozoites have recently been shown to be present in the same regions of the upper small intestine, whereas most mature cysts are found further down in the intestinal system. To learn more about host-parasite interactions during Giardia infections, we used an in vitro model of the parasite’s interaction with host IECs (differentiated Caco-2 cells) and Giardia WB trophozoites, early encysting cells (7 h), and cysts. Dual RNA sequencing (Dual RNAseq) was used to identify differentially expressed genes (DEGs) in both Giardia and the IECs, which might relate to establishing infection and disease induction. In the human cells, the largest gene expression changes were found in immune and MAPK signaling, transcriptional regulation, apoptosis, cholesterol metabolism and oxidative stress. The different life cycle stages of Giardia induced a core of similar DEGs but at different levels and there are many life cycle stage-specific DEGs. The metabolic protein PCK1, the transcription factors HES7, HEY1 and JUN, the peptide hormone CCK and the mucins MUC2 and MUC5A are up-regulated in the IECs by trophozoites but not cysts. Cysts specifically induce the chemokines CCL4L2, CCL5 and CXCL5, the signaling protein TRKA and the anti-bacterial protein WFDC12. The parasite, in turn, up-regulated a large number of hypothetical genes, high cysteine membrane proteins (HCMPs) and oxidative stress response genes. Early encysting cells have unique DEGs compared to trophozoites (e.g. several uniquely up-regulated HCMPs) and interaction of these cells with IECs affected the encystation process. Our data show that different life cycle stages of Giardia induce different gene expression responses in the host cells and that the IECs in turn differentially affect the gene expression in trophozoites and early encysting cells. This life cycle stage-specific host-parasite cross-talk is an important aspect to consider during further studies of Giardia’s molecular pathogenesis.
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Affiliation(s)
- Laura Rojas
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Jana Grüttner
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | | | - Feifei Xu
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Staffan G. Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
- SciLifeLab, Uppsala University, Uppsala, Sweden
- *Correspondence: Staffan G. Svärd,
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Krakovka S, Ribacke U, Miyamoto Y, Eckmann L, Svärd S. Characterization of Metronidazole-Resistant Giardia intestinalis Lines by Comparative Transcriptomics and Proteomics. Front Microbiol 2022; 13:834008. [PMID: 35222342 PMCID: PMC8866875 DOI: 10.3389/fmicb.2022.834008] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 01/13/2022] [Indexed: 12/13/2022] Open
Abstract
Metronidazole (MTZ) is a clinically important antimicrobial agent that is active against both bacterial and protozoan organisms. MTZ has been used extensively for more than 60 years and until now resistance has been rare. However, a recent and dramatic increase in the number of MTZ resistant bacteria and protozoa is of great concern since there are few alternative drugs with a similarly broad activity spectrum. To identify key factors and mechanisms underlying MTZ resistance, we utilized the protozoan parasite Giardia intestinalis, which is commonly treated with MTZ. We characterized two in vitro selected, metronidazole resistant parasite lines, as well as one revertant, by analyzing fitness aspects associated with increased drug resistance and transcriptomes and proteomes. We also conducted a meta-analysis using already existing data from additional resistant G. intestinalis isolates. The combined data suggest that in vitro generated MTZ resistance has a substantial fitness cost to the parasite, which may partly explain why resistance is not widespread despite decades of heavy use. Mechanistically, MTZ resistance in Giardia is multifactorial and associated with complex changes, yet a core set of pathways involving oxidoreductases, oxidative stress responses and DNA repair proteins, is central to MTZ resistance in both bacteria and protozoa.
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Affiliation(s)
- Sascha Krakovka
- Department of Cell and Molecular Biology, Biomedical Center (BMC), Uppsala University, Uppsala, Sweden
| | - Ulf Ribacke
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Yukiko Miyamoto
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Lars Eckmann
- Department of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Staffan Svärd
- Department of Cell and Molecular Biology, Biomedical Center (BMC), Uppsala University, Uppsala, Sweden.,SciLifeLab, Uppsala University, Uppsala, Sweden
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Oxygen levels are key to understanding "Anaerobic" protozoan pathogens with micro-aerophilic lifestyles. Adv Microb Physiol 2021; 79:163-240. [PMID: 34836611 DOI: 10.1016/bs.ampbs.2021.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Publications abound on the physiology, biochemistry and molecular biology of "anaerobic" protozoal parasites as usually grown under "anaerobic" culture conditions. The media routinely used are poised at low redox potentials using techniques that remove O2 to "undetectable" levels in sealed containers. However there is growing understanding that these culture conditions do not faithfully resemble the O2 environments these organisms inhabit. Here we review for protists lacking oxidative energy metabolism, the oxygen cascade from atmospheric to intracellular concentrations and relevant methods of measurements of O2, some well-studied parasitic or symbiotic protozoan lifestyles, their homeodynamic metabolic and redox balances, organism-drug-oxygen interactions, and the present and future prospects for improved drugs and treatment regimes.
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Nitroreductase Activites in Giardia lamblia: ORF 17150 Encodes a Quinone Reductase with Nitroreductase Activity. Pathogens 2021; 10:pathogens10020129. [PMID: 33513906 PMCID: PMC7912051 DOI: 10.3390/pathogens10020129] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/12/2021] [Accepted: 01/22/2021] [Indexed: 02/05/2023] Open
Abstract
The intestinal diplomonadid Giardia lamblia is a causative agent of persistent diarrhea. Current treatments are based on nitro drugs, especially metronidazole. Nitro compounds are activated by reduction, yielding toxic intermediates. The enzymatic systems responsible for this activation are not completely understood. By fractionating cell free crude extracts by size exclusion chromatography followed by mass spectrometry, enzymes with nitroreductase (NR) activities are identified. The protein encoded by ORF 17150 found in two pools with NR activities is overexpressed and characterized. In pools of fractions with main NR activities, previously-known NRs are identified, as well as a previously uncharacterized protein encoded by ORF 17150. Recombinant protein 17150 is a flavoprotein with NADPH-dependent quinone reductase and NR activities. Besides a set of previously identified NRs, we have identified a novel enzyme with NR activity.
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9
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Saghaug CS, Klotz C, Kallio JP, Aebischer T, Langeland N, Hanevik K. Genetic Diversity of the Flavohemoprotein Gene of Giardia lamblia: Evidence for High Allelic Heterozygosity and Copy Number Variation. Infect Drug Resist 2020; 13:4531-4545. [PMID: 33376360 PMCID: PMC7755369 DOI: 10.2147/idr.s274543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 10/29/2020] [Indexed: 12/12/2022] Open
Abstract
Purpose The flavohemoprotein (gFlHb) in Giardia plays an important role in managing nitrosative and oxidative stress, and potentially also in virulence and nitroimidazole drug tolerance. The aim of this study was to analyze the genetic diversity of gFlHb in Giardia assemblages A and B clinical isolates. Methods gFlHb genes from 20 cultured clinical Giardia isolates were subjected to PCR amplification and cloning, followed by Sanger sequencing. Sequences of all cloned PCR fragments from each isolate were analyzed for single nucleotide variants (SNVs) and compared to genomic Illumina sequence data. Identical clone sequences were sorted into alleles, and diversity was further analyzed. The number of gFlHb gene copies was assessed by mining PacBio de novo assembled genomes in eight isolates. Homology models for assessment of SNV's potential impact on protein function were created using Phyre2. Results A variable copy number of the gFlHb gene, between two and six copies, depending on isolate, was found. A total of 37 distinct sequences, representing different alleles of the gFlHb gene, were identified in AII isolates, and 41 were identified in B isolates. In some isolates, up to 12 different alleles were found. The total allelic diversity was high for both assemblages (>0.9) and was coupled with a nucleotide diversity of <0.01. The genetic variation (SNVs per CDS length) was 4.8% in sub-assemblage AII and 5.4% in assemblage B. The number of non-synonymous (ns) SNVs was high in gFIHb of both assemblages, 1.6% in A and 3.0% in B, respectively. Some of the identified nsSNV are predicted to alter protein structure and possibly function. Conclusion In this study, we present evidence that gFlHb, a putative protective enzyme against oxidative and nitrosative stress in Giardia, is a variable copy number gene with high allelic diversity. The genetic variability of gFlHb may contribute metabolic adaptability against metronidazole toxicity.
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Affiliation(s)
- Christina S Saghaug
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Christian Klotz
- Department of Infectious Diseases, Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Juha P Kallio
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Toni Aebischer
- Department of Infectious Diseases, Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Nina Langeland
- Department of Clinical Science, University of Bergen, Bergen, Norway.,Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Norway.,Department of Medicine, Haraldsplass Deaconess Hospital, Bergen, Norway
| | - Kurt Hanevik
- Department of Clinical Science, University of Bergen, Bergen, Norway
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10
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Wu P, An J, Chen L, Zhu Q, Li Y, Mei Y, Chen Z, Liang Y. Differential Analysis of Stress Tolerance and Transcriptome of Probiotic Lacticaseibacillus casei Zhang Produced from Solid-State (SSF-SW) and Liquid-State (LSF-MRS) Fermentations. Microorganisms 2020; 8:E1656. [PMID: 33114487 PMCID: PMC7716342 DOI: 10.3390/microorganisms8111656] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/21/2020] [Accepted: 10/22/2020] [Indexed: 12/18/2022] Open
Abstract
The property differences between bacteria produced from solid-state and liquid-state fermentations have always been the focus of attention. This study analyzed the stress tolerance and transcriptomic differences of the probiotic Lacticaseibacillus casei Zhang produced from solid-state and liquid-state fermentations under no direct stress. The total biomass of L. casei Zhang generated from liquid-state fermentation with MRS medium (LSF-MRS) was 2.24 times as much as that from solid-state fermentation with soybean meal-wheat bran (SSF-SW) medium. Interestingly, NaCl, H2O2, and ethanol stress tolerances and the survival rate after L. casei Zhang agent preparation from SSF-SW fermentation were significantly higher than those from LSF-MRS fermentation. The global transcriptomic analysis revealed that in L. casei Zhang produced from SSF-SW fermentation, carbohydrate transport, gluconeogenesis, inositol phosphate metabolism were promoted, that pentose phosphate pathway was up-regulated to produce more NADPH, that citrate transport and fermentation was extremely significantly promoted to produce pyruvate and ATP, and that pyruvate metabolism was widely up-regulated to form lactate, acetate, ethanol, and succinate from pyruvate and acetyl-CoA, whereas glycolysis was suppressed, and fatty acid biosynthesis was suppressed. Moreover, in response to adverse stresses, some genes encoding aquaporins (GlpF), superoxide dismutase (SOD), nitroreductase, iron homeostasis-related proteins, trehalose operon repressor TreR, alcohol dehydrogenase (ADH), and TetR/AcrR family transcriptional regulators were up-regulated in L. casei Zhang produced from SSF-SW fermentation. Our findings provide novel insight into the differences in growth performance, carbon and lipid metabolisms, and stress tolerance between L. casei Zhang from solid-state and liquid-state fermentations.
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Affiliation(s)
| | | | | | | | | | | | | | - Yunxiang Liang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (P.W.); (J.A.); (L.C.); (Q.Z.); (Y.L.); (Y.M.); (Z.C.)
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11
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Gavinho B, Sabatke B, Feijoli V, Rossi IV, da Silva JM, Evans-Osses I, Palmisano G, Lange S, Ramirez MI. Peptidylarginine Deiminase Inhibition Abolishes the Production of Large Extracellular Vesicles From Giardia intestinalis, Affecting Host-Pathogen Interactions by Hindering Adhesion to Host Cells. Front Cell Infect Microbiol 2020; 10:417. [PMID: 33072615 PMCID: PMC7539837 DOI: 10.3389/fcimb.2020.00417] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 07/07/2020] [Indexed: 12/16/2022] Open
Abstract
Giardia intestinalis is a microaerophilic protozoan that is an important etiologic agent of diarrhea worldwide. There is evidence that under diverse conditions, the parasite is capable of shedding extracellular vesicles (EVs) which modulate the physiopathology of giardiasis. Here we describe new features of G. intestinalis EV production, revealing its capacity to shed two different enriched EV populations: large (LEV) and small extracellular vesicles (SEV) and identified relevant adhesion functions associated with the larger population. Proteomic analysis revealed differences in proteins relevant for virulence and host-pathogen interactions between the two EV subsets, such as cytoskeletal and anti-oxidative stress response proteins in LEVS. We assessed the effect of two recently identified inhibitors of EV release in mammalian cells, namely peptidylarginine deiminase (PAD) inhibitor and cannabidiol (CBD), on EV release from Giardia. The compounds were both able to effectively reduce EV shedding, the PAD-inhibitor specifically affecting the release of LEVs and reducing parasite attachment to host cells in vitro. Our results suggest that LEVs and SEVs have a different role in host-pathogen interaction, and that treatment with EV-inhibitors may be a novel treatment strategy for recurrent giardiasis.
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Affiliation(s)
- Bruno Gavinho
- Programa de Pós-Graduação em Microbiologia, Parasitologia e Patologia, Departamento de Patologia, Universidade Federal do Paraná, Curitiba, Brazil
| | - Bruna Sabatke
- Programa de Pós-Graduação em Biologia Celular e Molecular, Departamento de Biologia Celular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Veronica Feijoli
- Departamento de Parasitologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, São Paulo, Brazil
| | - Izadora Volpato Rossi
- Programa de Pós-Graduação em Biologia Celular e Molecular, Departamento de Biologia Celular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Janaina Macedo da Silva
- Departamento de Parasitologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, São Paulo, Brazil
| | - Ingrid Evans-Osses
- Departamento de Enfermagem, Centro Universitario Santa Cruz, Curitiba, Brazil
| | - Giuseppe Palmisano
- Departamento de Parasitologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, São Paulo, Brazil
| | - Sigrun Lange
- Tissue Architecture and Regeneration Research Group, School of Life Sciences, University of Westminster, London, United Kingdom
| | - Marcel Ivan Ramirez
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil.,Instituto Oswaldo Cruz, Rio de Janeiro, Brazil
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Peirasmaki D, Ma'ayeh SY, Xu F, Ferella M, Campos S, Liu J, Svärd SG. High Cysteine Membrane Proteins (HCMPs) Are Up-Regulated During Giardia-Host Cell Interactions. Front Genet 2020; 11:913. [PMID: 33014015 PMCID: PMC7461913 DOI: 10.3389/fgene.2020.00913] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 07/22/2020] [Indexed: 12/13/2022] Open
Abstract
Giardia intestinalis colonizes the upper small intestine of humans and animals, causing the diarrheal disease giardiasis. This unicellular eukaryotic parasite is not invasive but it attaches to the surface of small intestinal epithelial cells (IECs), disrupting the epithelial barrier. Here, we used an in vitro model of the parasite’s interaction with host IECs (differentiated Caco-2 cells) and RNA sequencing (RNAseq) to identify differentially expressed genes (DEGs) in Giardia, which might relate to the establishment of infection and disease induction. Giardia trophozoites interacted with differentiated Caco-2 cells for 1.5, 3, and 4.5 h and at each time point, 61, 89, and 148 parasite genes were up-regulated more than twofold, whereas 209, 265, and 313 parasite genes were down-regulated more than twofold. The most abundant DEGs encode hypothetical proteins and members of the High Cysteine Membrane Protein (HCMP) family. Among the up-regulated genes we also observed proteins associated with proteolysis, cellular redox balance, as well as lipid and nucleic acid metabolic pathways. In contrast, genes encoding kinases, regulators of the cell cycle and arginine metabolism and cytoskeletal proteins were down-regulated. Immunofluorescence imaging of selected, up-regulated HCMPs, using C-terminal HA-tagging, showed localization to the plasma membrane and peripheral vesicles (PVs). The expression of the HCMPs was affected by histone acetylation and free iron-levels. In fact, the latter was shown to regulate the expression of many putative giardial virulence factors in subsequent RNAseq experiments. We suggest that the plasma membrane localized and differentially expressed HCMPs play important roles during Giardia-host cell interactions.
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Affiliation(s)
- Dimitra Peirasmaki
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Showgy Y Ma'ayeh
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Feifei Xu
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Marcela Ferella
- Eukaryotic Single Cell Genomics Platform, Karolinska Institute, Science for Life Laboratory (SciLifeLab), Solna, Sweden
| | - Sara Campos
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Jingyi Liu
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Staffan G Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.,Science for Life Laboratory (SciLifeLab), Uppsala University, Uppsala, Sweden
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13
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Kooyman FNJ, Wagenaar JA, Zomer A. Whole-genome sequencing of dog-specific assemblages C and D of Giardia duodenalis from single and pooled cysts indicates host-associated genes. Microb Genom 2020; 5. [PMID: 31821130 PMCID: PMC6939161 DOI: 10.1099/mgen.0.000302] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Giardia duodenalis (syn. Giardia intestinalis or Giardia lamblia) infSAects over 280 million people each year and numerous animals. G. duodenalis can be subdivided into eight assemblages with different host specificity. Unculturable assemblages have so far resisted genome sequencing efforts. In this study, we isolated single and pooled cysts of assemblages C and D from dog faeces by FACS, and sequenced them using multiple displacement amplification and Illumina paired-end sequencing. The genomes of assemblages C and D were compared with genomes of assemblages A and B from humans and assemblage E from ruminants and pigs. The genomes obtained from the pooled cysts and from the single cysts were considered complete (>99 % marker genes observed) and the allelic sequence heterozygosity (ASH) values of assemblages C and D were 0.89 and 0.74 %, respectively. These ASH values were slightly higher than for assemblage B (>0.43 %) and much higher than for assemblages A and E, which ranged from 0.002 to 0.037 %. The flavohaemoglobin and 4Fe-4S binding domain family encoding genes involved in O2 and NO detoxification were only present in assemblages A, B and E. Cathepsin B orthologs were found in all genomes. Six clades of cathepsin B orthologs contained one gene of each genome, while in three clades not all assemblages were represented. We conclude that whole-genome sequencing from a single Giardia cyst results in complete draft genomes, making the genomes of unculturable Giardia assemblages accessible. Observed differences between the genomes of assemblages C and D on one hand and the assemblages A, B and E on the other hand are possibly associated with host specificity.
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Affiliation(s)
- Frans N. J. Kooyman
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
- *Correspondence: Frans N. J. Kooyman,
| | - Jaap A. Wagenaar
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
- Wageningen Bioveterinary Research, Lelystad, The Netherlands
| | - Aldert Zomer
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
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Lauwaet T, Miyamoto Y, Ihara S, Le C, Kalisiak J, Korthals KA, Ghassemian M, Smith DK, Sharpless KB, Fokin VV, Eckmann L. Click chemistry-facilitated comprehensive identification of proteins adducted by antimicrobial 5-nitroimidazoles for discovery of alternative drug targets against giardiasis. PLoS Negl Trop Dis 2020; 14:e0008224. [PMID: 32302296 PMCID: PMC7190177 DOI: 10.1371/journal.pntd.0008224] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 04/29/2020] [Accepted: 03/16/2020] [Indexed: 12/21/2022] Open
Abstract
Giardiasis and other protozoan infections are major worldwide causes of morbidity and mortality, yet development of new antimicrobial agents with improved efficacy and ability to override increasingly common drug resistance remains a major challenge. Antimicrobial drug development typically proceeds by broad functional screens of large chemical libraries or hypothesis-driven exploration of single microbial targets, but both strategies have challenges that have limited the introduction of new antimicrobials. Here, we describe an alternative drug development strategy that identifies a sufficient but manageable number of promising targets, while reducing the risk of pursuing targets of unproven value. The strategy is based on defining and exploiting the incompletely understood adduction targets of 5-nitroimidazoles, which are proven antimicrobials against a wide range of anaerobic protozoan and bacterial pathogens. Comprehensive adductome analysis by modified click chemistry and multi-dimensional proteomics were applied to the model pathogen Giardia lamblia to identify dozens of adducted protein targets common to both 5'-nitroimidazole-sensitive and -resistant cells. The list was highly enriched for known targets in G. lamblia, including arginine deiminase, α-tubulin, carbamate kinase, and heat shock protein 90, demonstrating the utility of the approach. Importantly, over twenty potential novel drug targets were identified. Inhibitors of two representative new targets, NADP-specific glutamate dehydrogenase and peroxiredoxin, were found to have significant antigiardial activity. Furthermore, all the identified targets remained available in resistant cells, since giardicidal activity of the respective inhibitors was not impacted by resistance to 5'-nitroimidazoles. These results demonstrate that the combined use of click chemistry and proteomics has the potential to reveal alternative drug targets for overcoming antimicrobial drug resistance in protozoan parasites.
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Affiliation(s)
- Tineke Lauwaet
- Department of Pathology, University of California, San Diego, La Jolla, California, United States of America
| | - Yukiko Miyamoto
- Department of Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Sozaburo Ihara
- Department of Medicine, University of California, San Diego, La Jolla, California, United States of America.,Division of Gastroenterology, The Institute for Adult Diseases, Asahi Life Foundation, Tokyo, Japan
| | - Christine Le
- Department of Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Jarosław Kalisiak
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Keith A Korthals
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Majid Ghassemian
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, United States of America
| | - Diane K Smith
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California, United States of America
| | - K Barry Sharpless
- Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Valery V Fokin
- Department of Chemistry, Dornsife College of Letters, Arts and Sciences, University of Southern California, Los Angeles, California, United States of America
| | - Lars Eckmann
- Department of Medicine, University of California, San Diego, La Jolla, California, United States of America
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Jiménez-González A, Xu F, Andersson JO. Lateral Acquisitions Repeatedly Remodel the Oxygen Detoxification Pathway in Diplomonads and Relatives. Genome Biol Evol 2020; 11:2542-2556. [PMID: 31504492 PMCID: PMC6934886 DOI: 10.1093/gbe/evz188] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/19/2019] [Indexed: 12/13/2022] Open
Abstract
Oxygen and reactive oxygen species (ROS) are important stress factors for cells because they can oxidize many large molecules. Fornicata, a group of flagellated protists that includes diplomonads, have anaerobic metabolism but are still able to tolerate fluctuating levels of oxygen. We identified 25 protein families putatively involved in detoxification of oxygen and ROS in this group using a bioinformatics approach and propose how these interact in an oxygen detoxification pathway. These protein families were divided into a central oxygen detoxification pathway and accessory pathways for the synthesis of nonprotein thiols. We then used a phylogenetic approach to investigate the evolutionary origin of the components of this putative pathway in Diplomonadida and other Fornicata species. Our analyses suggested that the diplomonad ancestor was adapted to low-oxygen levels, was able to reduce O2 to H2O in a manner similar to extant diplomonads, and was able to synthesize glutathione and l-cysteine. Several genes involved in the pathway have complex evolutionary histories and have apparently been repeatedly acquired through lateral gene transfer and subsequently lost. At least seven genes were acquired independently in different Fornicata lineages, leading to evolutionary convergences. It is likely that acquiring these oxygen detoxification proteins helped anaerobic organisms (like the parasitic Giardia intestinalis) adapt to low-oxygen environments (such as the digestive tract of aerobic hosts).
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Affiliation(s)
- Alejandro Jiménez-González
- Uppsala Biomedicine Centre, Department of Cell and Molecular Biology, Molecular Evolution Program, Uppsala University, Sweden
| | - Feifei Xu
- Uppsala Biomedicine Centre, Department of Cell and Molecular Biology, Microbiology Program, Uppsala University, Sweden
| | - Jan O Andersson
- Uppsala Biomedicine Centre, Department of Cell and Molecular Biology, Molecular Evolution Program, Uppsala University, Sweden
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16
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Jex AR, Svärd S, Hagen KD, Starcevich H, Emery-Corbin SJ, Balan B, Nosala C, Dawson SC. Recent advances in functional research in Giardia intestinalis. ADVANCES IN PARASITOLOGY 2020; 107:97-137. [PMID: 32122532 PMCID: PMC7878119 DOI: 10.1016/bs.apar.2019.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This review considers current advances in tools to investigate the functional biology of Giardia, it's coding and non-coding genes, features and cellular and molecular biology. We consider major gaps in current knowledge of the parasite and discuss the present state-of-the-art in its in vivo and in vitro cultivation. Advances in in silico tools, including for the modelling non-coding RNAs and genomic elements, as well as detailed exploration of coding genes through inferred homology to model organisms, have provided significant, primary level insight. Improved methods to model the three-dimensional structure of proteins offer new insights into their function, and binding interactions with ligands, other proteins or precursor drugs, and offer substantial opportunities to prioritise proteins for further study and experimentation. These approaches can be supplemented by the growing and highly accessible arsenal of systems-based methods now being applied to Giardia, led by genomic, transcriptomic and proteomic methods, but rapidly incorporating advanced tools for detection of real-time transcription, evaluation of chromatin states and direct measurement of macromolecular complexes. Methods to directly interrogate and perturb gene function have made major leaps in recent years, with CRISPr-interference now available. These approaches, coupled with protein over-expression, fluorescent labelling and in vitro and in vivo imaging, are set to revolutionize the field and herald an exciting time during which the field may finally realise Giardia's long proposed potential as a model parasite and eukaryote.
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Affiliation(s)
- Aaron R Jex
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia; Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, Australia.
| | - Staffan Svärd
- Centre for Biomedicine, Uppsala University, Uppsala, Sweden
| | - Kari D Hagen
- College of Biological Sciences, University of California-Davis, Davis, CA, United States
| | - Hannah Starcevich
- College of Biological Sciences, University of California-Davis, Davis, CA, United States
| | - Samantha J Emery-Corbin
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia
| | - Balu Balan
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia
| | - Chris Nosala
- College of Biological Sciences, University of California-Davis, Davis, CA, United States
| | - Scott C Dawson
- College of Biological Sciences, University of California-Davis, Davis, CA, United States
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17
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Müller J, Vermathen M, Leitsch D, Vermathen P, Müller N. Metabolomic Profiling of Wildtype and Transgenic Giardia lamblia Strains by 1H HR-MAS NMR Spectroscopy. Metabolites 2020; 10:metabo10020053. [PMID: 32019059 PMCID: PMC7073884 DOI: 10.3390/metabo10020053] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/21/2020] [Accepted: 01/28/2020] [Indexed: 12/24/2022] Open
Abstract
Giardia lamblia, a causative agent of persistent diarrhea in humans, domestic animals, and cattle, is usually treated with nitro compounds. Consequently, enzymes involved in anaerobic nitro reduction have been investigated in detail as potential targets. Their role within the normal metabolic context is, however, not understood. Using 1H high-resolution magic angle spinning (HR-MAS) NMR spectroscopy, we analyzed the metabolomes of G. lamblia trophozoites overexpressing three nitroreductases (NR1–NR3) and thioredoxin reductase (TrxR), most likely a scavenger of reactive oxygen species, as suggested by the results published in this study. We compared the patterns to convenient controls and to the situation in the nitro drug resistant strain C4 where NR1 is downregulated. We identified 27 metabolites in G. lamblia trophozoites. Excluding metabolites of high variability among different wildtype populations, only trophozoites overexpressing NR1 presented a distinct pattern of nine metabolites, in particular arginine catabolites, differing from the respective controls. This pattern matched a differential pattern between wildtype and strain C4. This suggests that NR1 interferes with arginine and thus energy metabolism. The exact metabolic function of NR1 (and the other nitroreductases) remains to be elucidated.
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Affiliation(s)
- Joachim Müller
- Institute of Parasitology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, CH-3012 Bern, Switzerland;
- Correspondence:
| | - Martina Vermathen
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland;
| | - David Leitsch
- Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Kinderspitalgasse 15, A-1090 Vienna, Austria;
| | - Peter Vermathen
- Departments of BioMedical Research and Radiology, University and Inselspital Bern, sitem-insel AG Freiburgstr. 3, CH-3010 Bern, Switzerland;
| | - Norbert Müller
- Institute of Parasitology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, CH-3012 Bern, Switzerland;
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18
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A review on the druggability of a thiol-based enzymatic antioxidant thioredoxin reductase for treating filariasis and other parasitic infections. Int J Biol Macromol 2020; 142:125-141. [DOI: 10.1016/j.ijbiomac.2019.09.083] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/10/2019] [Accepted: 09/11/2019] [Indexed: 01/07/2023]
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19
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Emery-Corbin SJ, Grüttner J, Svärd S. Transcriptomic and proteomic analyses of Giardia intestinalis: Intestinal epithelial cell interactions. ADVANCES IN PARASITOLOGY 2019; 107:139-171. [PMID: 32122528 DOI: 10.1016/bs.apar.2019.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Giardia intestinalis is a unicellular protozoan parasite that infects the small intestines of humans and animals. Giardiasis, the disease caused by the parasite, occurs globally across socioeconomic boundaries but is mainly endemic in developing countries and particularly within young children, where pronounced effects manifests in a failure to thrive condition. The molecular pathogenesis of Giardia has been studied using in vitro models of human and rat intestinal epithelial cells (IECs) and parasites from the two major human genotypes or assemblages (A and B). High-quality, genome sequencing of representative isolates from assemblages A (WB) and B (GS) has enabled exploration of these host-parasite models using 'omics' technologies, allowing deep and quantitative analyses of global gene expression changes in IECs and parasites during their interactions, cross-talk and competition. These include a major up-regulation of immune-related genes in the IECs early after the start of interactions, as well as competition between host cells and parasites for nutrients like sugars, amino acids and lipids, which is also reflected in their secretome interactions. Unique parasite proteins dominate these interactions, with many major up-regulated genes being either hypothetical proteins or members of Giardia-specific gene families like the high-cysteine-rich membrane proteins (HCMPs), variable surface proteins (VSPs), alpha-giardins and cysteine proteases. Furthermore, these proteins also dominate in the secretomes, suggesting that they are important virulence factors in Giardia and crucial molecular effectors at the host-parasite interface.
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Affiliation(s)
- Samantha J Emery-Corbin
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Melbourne, VIC, Australia
| | - Jana Grüttner
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Staffan Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
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20
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Müller J, Müller N. Nitroreductases of bacterial origin in Giardia lamblia: Potential role in detoxification of xenobiotics. Microbiologyopen 2019; 8:e904. [PMID: 31343119 PMCID: PMC7938412 DOI: 10.1002/mbo3.904] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 06/19/2019] [Accepted: 06/19/2019] [Indexed: 11/05/2022] Open
Abstract
The anaerobic parasite Giardia lamblia, causative agent of persistent diarrhea, contains a family of nitroreductase genes most likely acquired by lateral transfer from anaerobic bacteria or archaebacteria. Two of these nitroreductases, containing a ferredoxin domain at their N-terminus, NR1, and NR2, have been characterized previously. Here, we present the characterization of a third member of this family, NR3. In functional assays, recombinant NR1 and NR3 reduced quinones like menadione and the antibiotic tetracycline, and-to much lesser extents-the nitro compound dinitrotoluene. Conversely, recombinant NR2 had no activity on tetracycline. Escherichia coli expressing NR3 were less susceptible to tetracycline, but more susceptible to the nitro compound metronidazole under semi-aerobic growth conditions. G. lamblia overexpressing NR1 and NR3, but not lines overexpressing NR2, are more susceptible to the nitro drug nitazoxanide. These findings suggest that NR3 is an active quinone reductase with a mode of action similar to NR1, but different from NR2. The biological function of this family of enzymes may reside in the use of xenobiotics as final electron acceptors. Thereby, these enzymes may provide at least two evolutionary advantages namely a higher potential to recycle NAD(P) as electron acceptors for the (fermentative) energy and intermediary metabolism, and the possibility to inactivate toxic xenobiotics produced by microorganisms living in concurrence inside the intestinal habitat.
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Affiliation(s)
- Joachim Müller
- Vetsuisse Faculty, Institute of Parasitology, University of Berne, Berne, Switzerland
| | - Norbert Müller
- Vetsuisse Faculty, Institute of Parasitology, University of Berne, Berne, Switzerland
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21
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Saghaug CS, Klotz C, Kallio JP, Brattbakk HR, Stokowy T, Aebischer T, Kursula I, Langeland N, Hanevik K. Genetic variation in metronidazole metabolism and oxidative stress pathways in clinical Giardia lamblia assemblage A and B isolates. Infect Drug Resist 2019; 12:1221-1235. [PMID: 31190910 PMCID: PMC6519707 DOI: 10.2147/idr.s177997] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/16/2019] [Indexed: 12/12/2022] Open
Abstract
Purpose: Treatment-refractory Giardia cases have increased rapidly within the last decade. No markers of resistance nor a standardized susceptibility test have been established yet, but several enzymes and their pathways have been associated with metronidazole (MTZ) resistant Giardia. Very limited data are available regarding genetic variation in these pathways. We aimed to investigate genetic variation in metabolic pathway genes proposed to be involved in MTZ resistance in recently acquired, cultured clinical isolates. Methods: Whole genome sequencing of 12 assemblage A2 and 8 assemblage B isolates was done, to decipher genomic variation in Giardia. Twenty-nine genes were identified in a literature search and investigated for their single nucleotide variants (SNVs) in the coding/non-coding regions of the genes, either as amino acid changing (non-synonymous SNVs) or non-changing SNVs (synonymous). Results: In Giardia assemblage B, several genes involved in MTZ activation or oxidative stress management were found to have higher numbers of non-synonymous SNVs (thioredoxin peroxidase, nitroreductase 1, ferredoxin 2, NADH oxidase, nitroreductase 2, alcohol dehydrogenase, ferredoxin 4 and ferredoxin 1) than the average variation. For Giardia assemblage A2, the highest genetic variability was found in the ferredoxin 2, ferredoxin 6 and in nicotinamide adenine dinucleotide phosphate (NADPH) oxidoreductase putative genes. SNVs found in the ferredoxins and nitroreductases were analyzed further by alignment and homology modeling. SNVs close to the iron-sulfur cluster binding sites in nitroreductase-1 and 2 and ferredoxin 2 and 4 could potentially affect protein function. Flavohemoprotein seems to be a variable-copy gene, due to higher, but variable coverage compared to other genes investigated. Conclusion: In clinical Giardia isolates, genetic variability is common in important genes in the MTZ metabolizing pathway and in the management of oxidative and nitrosative stress and includes high numbers of non-synonymous SNVs. Some of the identified amino acid changes could potentially affect the respective proteins important in the MTZ metabolism.
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Affiliation(s)
- Christina S Saghaug
- Department of Clinical Science, University of Bergen, Bergen, Hordaland, Norway.,Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Hordaland, Norway
| | - Christian Klotz
- Department of Infectious Diseases, Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Juha P Kallio
- Department of Biomedicine, University of Bergen, Bergen, Hordaland, Norway
| | - Hans-Richard Brattbakk
- Department of Clinical Science, University of Bergen, Bergen, Hordaland, Norway.,Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Hordaland, Norway
| | - Tomasz Stokowy
- Department of Clinical Science, University of Bergen, Bergen, Hordaland, Norway.,Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Hordaland, Norway
| | - Toni Aebischer
- Department of Infectious Diseases, Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Inari Kursula
- Department of Biomedicine, University of Bergen, Bergen, Hordaland, Norway.,Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Nina Langeland
- Department of Clinical Science, University of Bergen, Bergen, Hordaland, Norway.,Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Hordaland, Norway.,Department of Medicine, Haraldsplass Deaconess Hospital, Bergen, Hordaland, Norway
| | - Kurt Hanevik
- Department of Clinical Science, University of Bergen, Bergen, Hordaland, Norway.,Norwegian National Advisory Unit on Tropical Infectious Diseases, Department of Medicine, Haukeland University Hospital, Bergen, Hordaland, Norway
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22
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Müller J, Braga S, Heller M, Müller N. Resistance formation to nitro drugs in Giardia lamblia: No common markers identified by comparative proteomics. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2019; 9:112-119. [PMID: 30889439 PMCID: PMC6423486 DOI: 10.1016/j.ijpddr.2019.03.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 02/15/2019] [Accepted: 03/12/2019] [Indexed: 02/07/2023]
Abstract
In order to elucidate the question whether resistance to nitro drugs in G. lamblia is due to common resistance markers, trophozoites of three resistant G. lamblia strains, namely C4, 1062ID10, and 713M3 were grown in the presence of the two nitro drugs metronidazole and nitazoxanide and compared to their corresponding wild-types WBC6, 106, and 713 by mass spectometry shotgun analysis of their proteomes. Depending on the strain and the nitro drug, more than 200 to 500 differentially expressed proteins were identified, but there were no common patterns across strains and drugs. All resistant strains underwent antigenic variation with distinct surface antigens like variant surface proteins or cysteine rich proteins depending on strain and nitro compound. A closer look on enzymes involved in nitroreduction and detoxification of nitro radicals, NO or O2 suggested the existence of distinct strategies for each drug and each strain. Therefore, we conclude that resistance to nitro drugs in G. lamblia is not correlated with a specific pattern of differentially expressed proteins and therefore seems not to be the result of a directed process. Is resistance to nitro drugs in G. lamblia due to common resistance markers? Three resistant strains were grown in the presence of two nitro drugs separately and compared to wild-types by MS shotgun analysis. More than 200 to 500 differentially expressed proteins identified depending on strain and drug. No common patterns across strains and drugs. Strain specific antigenic variation and strategies linked to nitro reduction.
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Affiliation(s)
- Joachim Müller
- Institute of Parasitology, Vetsuisse Faculty, University of Berne, Länggass-Strasse 122, CH-3012, Berne, Switzerland.
| | - Sophie Braga
- Proteomics & Mass Spectrometry Core Facility, Department for BioMedical Research (DBMR), University of Berne, Freiburgstrasse 15, CH-3010, Berne, Switzerland.
| | - Manfred Heller
- Proteomics & Mass Spectrometry Core Facility, Department for BioMedical Research (DBMR), University of Berne, Freiburgstrasse 15, CH-3010, Berne, Switzerland.
| | - Norbert Müller
- Institute of Parasitology, Vetsuisse Faculty, University of Berne, Länggass-Strasse 122, CH-3012, Berne, Switzerland.
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23
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Stairs CW, Kokla A, Ástvaldsson Á, Jerlström-Hultqvist J, Svärd S, Ettema TJG. Oxygen induces the expression of invasion and stress response genes in the anaerobic salmon parasite Spironucleus salmonicida. BMC Biol 2019; 17:19. [PMID: 30823887 PMCID: PMC6397501 DOI: 10.1186/s12915-019-0634-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 02/06/2019] [Indexed: 01/01/2023] Open
Abstract
Background Spironucleus salmonicida is an anaerobic parasite that can cause systemic infections in Atlantic salmon. Unlike other diplomonad parasites, such as the human pathogen Giardia intestinalis, Spironucleus species can infiltrate the blood stream of their hosts eventually colonizing organs, skin and gills. How this presumed anaerobe can persist and invade oxygenated tissues, despite having a strictly anaerobic metabolism, remains elusive. Results To investigate how S. salmonicida response to oxygen stress, we performed RNAseq transcriptomic analyses of cells grown in the presence of oxygen or antioxidant-free medium. We found that over 20% of the transcriptome is differentially regulated in oxygen (1705 genes) and antioxidant-depleted (2280 genes) conditions. These differentially regulated transcripts encode proteins related to anaerobic metabolism, cysteine and Fe-S cluster biosynthesis, as well as a large number of proteins of unknown function. S. salmonicida does not encode genes involved in the classical elements of oxygen metabolism (e.g., catalases, superoxide dismutase, glutathione biosynthesis, oxidative phosphorylation). Instead, we found that genes encoding bacterial-like oxidoreductases were upregulated in response to oxygen stress. Phylogenetic analysis revealed some of these oxygen-responsive genes (e.g., nadh oxidase, rubrerythrin, superoxide reductase) are rare in eukaryotes and likely derived from lateral gene transfer (LGT) events into diplomonads from prokaryotes. Unexpectedly, we observed that many host evasion- and invasion-related genes were also upregulated under oxidative stress suggesting that oxygen might be an important signal for pathogenesis. Conclusion While oxygen is toxic for related organisms, such as G. intestinalis, we find that oxygen is likely a gene induction signal for host invasion- and evasion-related pathways in S. salmonicida. These data provide the first molecular evidence for how S. salmonicida could tolerate oxic host environments and demonstrate how LGT can have a profound impact on the biology of anaerobic parasites. Electronic supplementary material The online version of this article (10.1186/s12915-019-0634-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Courtney W Stairs
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.
| | - Anna Kokla
- Present Address: Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), Almas Allé 5, BioCentrum, room D-444, Uppsala, Sweden
| | - Ásgeir Ástvaldsson
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Jon Jerlström-Hultqvist
- Present Address: Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Canada
| | - Staffan Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Thijs J G Ettema
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden.,Laboratory of Microbiology, Department of Agrotechnology and Food Sciences, Wageningen University, Stippeneng 4, 6708WE, Wageningen, The Netherlands
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24
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Emery SJ, Baker L, Ansell BRE, Mirzaei M, Haynes PA, McConville MJ, Svärd SG, Jex AR. Differential protein expression and post-translational modifications in metronidazole-resistant Giardia duodenalis. Gigascience 2018; 7:4931738. [PMID: 29688452 PMCID: PMC5913674 DOI: 10.1093/gigascience/giy024] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 03/06/2018] [Indexed: 01/20/2023] Open
Abstract
Background Metronidazole (Mtz) is the frontline drug treatment for multiple anaerobic pathogens, including the gastrointestinal protist, Giardia duodenalis. However, treatment failure is common and linked to in vivo drug resistance. In Giardia, in vitro drug-resistant lines allow controlled experimental interrogation of resistance mechanisms in isogenic cultures. However, resistance-associated changes are inconsistent between lines, phenotypic data are incomplete, and resistance is rarely genetically fixed, highlighted by reversion to sensitivity after drug selection ceases or via passage through the life cycle. Comprehensive quantitative approaches are required to resolve isolate variability, fully define Mtz resistance phenotypes, and explore the role of post-translational modifications therein. Findings We performed quantitative proteomics to describe differentially expressed proteins in 3 seminal Mtz-resistant lines compared to their isogenic, Mtz-susceptible, parental line. We also probed changes in post-translational modifications including protein acetylation, methylation, ubiquitination, and phosphorylation via immunoblotting. We quantified more than 1,000 proteins in each genotype, recording substantial genotypic variation in differentially expressed proteins between isotypes. Our data confirm substantial changes in the antioxidant network, glycolysis, and electron transport and indicate links between protein acetylation and Mtz resistance, including cross-resistance to deacetylase inhibitor trichostatin A in Mtz-resistant lines. Finally, we performed the first controlled, longitudinal study of Mtz resistance stability, monitoring lines after cessation of drug selection, revealing isolate-dependent phenotypic plasticity. Conclusions Our data demonstrate understanding that Mtz resistance must be broadened to post-transcriptional and post-translational responses and that Mtz resistance is polygenic, driven by isolate-dependent variation, and is correlated with changes in protein acetylation networks.
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Affiliation(s)
- Samantha J Emery
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
| | - Louise Baker
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Brendan R E Ansell
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Mehdi Mirzaei
- Chemistry and Biomolecular Sciences, Faculty of Science, Macquarie University, North Ryde, NSW, Australia.,Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW, Australia
| | - Paul A Haynes
- Chemistry and Biomolecular Sciences, Faculty of Science, Macquarie University, North Ryde, NSW, Australia
| | - Malcom J McConville
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Staffan G Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Aaron R Jex
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, Australia
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25
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Datta SP, Jana K, Mondal A, Ganguly S, Sarkar S. Multiple paralogues of α-SNAP in Giardia lamblia exhibit independent subcellular localization and redistribution during encystation and stress. Parasit Vectors 2018; 11:539. [PMID: 30286802 PMCID: PMC6172762 DOI: 10.1186/s13071-018-3112-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 09/13/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The differently-diverged parasitic protist Giardia lamblia is known to have minimal machinery for vesicular transport. Yet, it has three paralogues of SNAP, a crucial component that together with NSF brings about disassembly of the cis-SNARE complex formed following vesicle fusion to target membranes. Given that most opisthokont hosts of this gut parasite express only one α-SNAP, this study was undertaken to determine whether these giardial SNAP proteins have undergone functional divergence. RESULTS All three SNAP paralogues are expressed in trophozoites, encysting trophozoites and cysts. Even though one of them clusters with γ-SNAP sequences in a phylogenetic tree, functional complementation analysis in yeast indicates that all the three proteins are functionally orthologous to α-SNAP. Localization studies showed a mostly non-overlapping distribution of these α-SNAPs in trophozoites, encysting cells and cysts. In addition, two of the paralogues exhibit substantial subcellular redistribution during encystation, which was also seen following exposure to oxidative stress. However, the expression of the three genes remained unchanged during this redistribution process. There is also a difference in the affinity of each of these α-SNAP paralogues for GlNSF. CONCLUSIONS None of the genes encoding the three α-SNAPs are pseudogenes and the encoded proteins are likely to discharge non-redundant functions in the different morphological states of G. lamblia. Based on the difference in the interaction of individual α-SNAPs with GlNSF and their non-overlapping pattern of subcellular redistribution during encystation and under stress conditions, it may be concluded that the three giardial α-SNAP paralogues have undergone functional divergence. Presence of one of the giardial α-SNAPs at the PDRs of flagella, where neither GlNSF nor any of the SNAREs localize, indicates that this α-SNAP discharges a SNARE-independent role in this gut pathogen.
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Affiliation(s)
- Shankari Prasad Datta
- Department of Biochemistry, Bose Institute, P 1/12 CIT Road Scheme VII M, Kolkata, West Bengal, 700054, India
| | - Kuladip Jana
- Division of Molecular Medicine, Bose Institute, P 1/12 CIT Road Scheme VII M, Kolkata, West Bengal, 700054, India
| | - Avisek Mondal
- Department of Biochemistry, Bose Institute, P 1/12 CIT Road Scheme VII M, Kolkata, West Bengal, 700054, India.,Present Address: Section on Developmental Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, Maryland, USA
| | - Sandipan Ganguly
- Division of Parasitology, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme XM, Beliaghata, Kolkata, West Bengal, 700010, India
| | - Srimonti Sarkar
- Department of Biochemistry, Bose Institute, P 1/12 CIT Road Scheme VII M, Kolkata, West Bengal, 700054, India.
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26
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Ordoñez-Quiroz A, Ortega-Pierres MG, Bazán-Tejeda ML, Bermúdez-Cruz RM. DNA damage induced by metronidazole in Giardia duodenalis triggers a DNA homologous recombination response. Exp Parasitol 2018; 194:24-31. [PMID: 30237050 DOI: 10.1016/j.exppara.2018.09.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 07/14/2018] [Accepted: 09/15/2018] [Indexed: 01/29/2023]
Abstract
The mechanisms underlying metronidazole (MTZ) resistance in Giardia duodenalis have been associated with decreased activity of the enzymes implicated in its activation including nitroductase-1, thioredoxin reductase and pyruvate-ferredoxin oxidoreductase (PFOR). MTZ activation generates radicals that can form adducts with proteins such as thioredoxin reductase and α- and -β giardins as well as DNA damage resulting in trophozoite's death. The damage induced in DNA requires a straight forward response that may allow parasite survival. Here, we studied changes in histone H2A phosphorylation to evaluate the DNA repair response pathway after induction of double strand break (DSB) by MTZ in Giardia DNA. Our results showed that the DNA repair mechanisms after exposure of Giardia trophozoites to MTZ, involved a homologous recombination pathway. We observed a significant increase in the expression level of proteins GdDMC1B, which carries out Rad51 role in G. duodenalis, and GdMre11, after 12 h of exposure to 3.2 μM MTZ. This increase was concomitant with the generation of DSB in the DNA of trophozoites treated MTZ. Altogether, these results suggest that MTZ-induced DNA damage in Giardia triggers the DNA homologous recombination repair (DHRR) pathway, which may contribute to the parasite survival in the presence of MTZ.
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Affiliation(s)
- Angel Ordoñez-Quiroz
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico Nacional No. 2508, C.P.07360, México D.F, Mexico
| | - M Guadalupe Ortega-Pierres
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico Nacional No. 2508, C.P.07360, México D.F, Mexico
| | - María Luisa Bazán-Tejeda
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico Nacional No. 2508, C.P.07360, México D.F, Mexico
| | - Rosa M Bermúdez-Cruz
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico Nacional No. 2508, C.P.07360, México D.F, Mexico.
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27
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Ortega-Pierres M, Jex AR, Ansell BR, Svärd SG. Recent advances in the genomic and molecular biology of Giardia. Acta Trop 2018; 184:67-72. [PMID: 28888474 DOI: 10.1016/j.actatropica.2017.09.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 09/05/2017] [Indexed: 01/01/2023]
Abstract
Giardia duodenalis is the most common gastrointestinal protozoan parasite of humans and a significant contributor to the global burden of both diarrheal disease and post-infectious chronic disorders. Robust tools for analyzing gene function in this parasite have been developed and a range of genetic tools are now available. These together with public databases have provided insights on the function of different genes in Giardia. In this review we provide a current perspective on different molecular aspects of Giardia related to genomics, regulation of encystation, trophozoite transcriptional responses to physiological and xenobiotic (drug-induced) stress, and mechanisms of drug resistance. We also examine recent insights that have contributed to gain knowledge in the study of VSPs, antigenic variation, epigenetics, DNA repair and in the direct manipulation of gene function in Giardia, with a particular focus on the inducible Cre/loxP system.
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28
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Ma'ayeh SY, Knörr L, Sköld K, Garnham A, Ansell BRE, Jex AR, Svärd SG. Responses of the Differentiated Intestinal Epithelial Cell Line Caco-2 to Infection With the Giardia intestinalis GS Isolate. Front Cell Infect Microbiol 2018; 8:244. [PMID: 30062089 PMCID: PMC6055019 DOI: 10.3389/fcimb.2018.00244] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/25/2018] [Indexed: 12/11/2022] Open
Abstract
Giardia intestinalis is a parasitic protist that causes diarrhea in humans, affecting mainly children of the developing world, elderly and immunocompromised individuals. Humans are infected by two major Giardia assemblages (i.e. genetic subtypes), A and B, with the latter being the most common. So far, there is little information on molecular or cellular changes during infections with assemblage B. Here, we used RNA sequencing to study transcriptional changes in Caco-2 intestinal epithelial cells (IECs) co-incubated with assemblage B (GS isolate) trophozoites for 1.5, 3, and 4.5 h. We aimed to identify early molecular events associated with the establishment of infection and followed cellular protein changes up to 10 h. IEC transcriptomes showed a dominance of immediate early response genes which was sustained across all time points. Transcription of inflammatory cytokines (e.g., cxcl1-3, ccl2, 1l1a, and il1b) peaked at 1.5 and 3 h of infection. Compared to co-incubation with assemblage A Giardia, we identified the induction of novel cytokines (cxcl8, cxcl10, csf1, cx3cl1, il12a, il11) and showed that inflammatory signaling is mediated by Erk1/2 phosphorylation (mitogen activated protein kinase, MAPK), nuclear factor kappa B (NFκB) and adaptor protein-1 (AP-1). We also showed that GS trophozoites attenuate P38 (MAPK) phosphorylation in IECs. Low amounts of IL-8, CXCL1 and CCL20 proteins were measured in the interaction medium, which was attributed to cytokine degradation by trophozoite secreted proteases. Based on the transcriptome, the decay of cytokines mRNA mediated by zinc finger protein 36 might be another mechanism controlling cytokine levels at later time points. IEC transcriptomes suggested homeostatic responses to counter oxidative stress, glucose starvation, and disturbances in amino acid and lipid metabolism. A large group of differentially transcribed genes were associated with cell cycle arrest and induction of apoptosis, which was validated at protein level. IEC transcriptomes also suggested changes in tight junction's integrity, microvilli structure and the extracellular mucin layer. This is the first study to illuminate transcriptional and protein regulatory events underlying IECs responses and pathogenesis during Giardia assemblage B infection. It highlights differences compared to assemblage A infections which might account for the differences observed in human infections with the two assemblages.
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Affiliation(s)
- Showgy Y Ma'ayeh
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Livia Knörr
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Karin Sköld
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Alexandra Garnham
- Population Health & Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
| | - Brendan R E Ansell
- Population Health & Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Faculty of Veterinary Science, The University of Melbourne, Parkville, VIC, Australia
| | - Aaron R Jex
- Population Health & Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia.,Faculty of Veterinary Science, The University of Melbourne, Parkville, VIC, Australia
| | - Staffan G Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
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29
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1H HR-MAS NMR spectroscopy to study the metabolome of the protozoan parasite Giardia lamblia. Talanta 2018; 188:429-441. [PMID: 30029398 DOI: 10.1016/j.talanta.2018.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 05/29/2018] [Accepted: 06/01/2018] [Indexed: 12/30/2022]
Abstract
Knowledge of the metabolic profile and exchange processes in the protozoan parasite Giardia lamblia is of importance for a better understanding of the biochemical processes and for the development of drugs to control diseases caused by G. lamblia. In the current paper, 1H High Resolution Magic Angle Spinning (HR-MAS) NMR spectroscopy was directly applied to G. lamblia trophozoite suspensions to analyze the detectable small metabolites with a minimum of intervention. Thirty-one components were identified with main contributions from amino acids such as alanine and ornithine. The reproducibility, variability, and stability of the metabolites were investigated. Citrulline was found to be formed as an intermediate and citrulline levels depended on the stage of cell growth. Glucose-1-phosphate was found to be formed in relatively high amounts after cell harvesting if enzymes were not inactivated. In addition, the metabolic footprint of Giardia trophozoites, i.e. changes in the culture medium induced by G. lamblia, was investigated by liquid state NMR spectroscopy of culture media before and after inoculation. A quantitative comparison of the NMR spectra revealed component changes in the culture media during growth. The results suggested that not glucose but rather arginine serves as main energy supply. Biochemical functions of intracellular components and their metabolic exchange with the culture medium are discussed. The results provide an important basis for the design of HR-MAS NMR based metabolomic studies of G. lamblia in particular and any protozoan parasite samples in general.
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30
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Leitsch D, Williams CF, Hrdý I. Redox Pathways as Drug Targets in Microaerophilic Parasites. Trends Parasitol 2018; 34:576-589. [PMID: 29807758 DOI: 10.1016/j.pt.2018.04.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 04/27/2018] [Accepted: 04/28/2018] [Indexed: 01/06/2023]
Abstract
The microaerophilic parasites Entamoeba histolytica, Trichomonas vaginalis, and Giardia lamblia jointly cause hundreds of millions of infections in humans every year. Other microaerophilic parasites such as Tritrichomonas foetus and Spironucleus spp. pose a relevant health problem in veterinary medicine. Unfortunately, vaccines against these pathogens are unavailable, but their microaerophilic lifestyle opens opportunities for specifically developed chemotherapeutics. In particular, their high sensitivity towards oxygen can be exploited by targeting redox enzymes. This review focusses on the redox pathways of microaerophilic parasites and on drugs, either already in use or currently in the state of development, which target these pathways.
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Affiliation(s)
- David Leitsch
- Institute for Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology, and Immunology, Medical University of Vienna, Austria.
| | - Catrin F Williams
- School of Engineering, Cardiff University, Cardiff, Wales, United Kingdom
| | - Ivan Hrdý
- Department of Parasitology, Charles University, Faculty of Science, Prague, Czech Republic
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31
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Raj D, Chowdhury P, Sarkar R, Saito-Nakano Y, Okamoto K, Dutta S, Nozaki T, Ganguly S. Pyruvate Protects Giardia Trophozoites from Cysteine-Ascorbate Deprived Medium Induced Cytotoxicity. THE KOREAN JOURNAL OF PARASITOLOGY 2018. [PMID: 29529844 PMCID: PMC5858663 DOI: 10.3347/kjp.2018.56.1.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Giardia lamblia, an anaerobic, amitochondriate protozoan parasite causes parasitic infection giardiasis in children and young adults. It produces pyruvate, a major metabolic product for its fermentative metabolism. The current study was undertaken to explore the effects of pyruvate as a physiological antioxidant during oxidative stress in Giardia by cysteine-ascorbate deprivation and further investigation upon the hypothesis that oxidative stress due to metabolism was the reason behind the cytotoxicity. We have estimated intracellular reactive oxygen species generation due to cysteine-ascorbate deprivation in Giardia. In the present study, we have examined the effects of extracellular addition of pyruvate, during oxidative stress generated from cysteine-ascorbate deprivation in culture media on DNA damage in Giardia. The intracellular pyruvate concentrations at several time points were measured in the trophozoites during stress. Trophozoites viability under cysteine-ascorbate deprived (CAD) medium in presence and absence of extracellular pyruvate has also been measured. The exogenous addition of a physiologically relevant concentration of pyruvate to trophozoites suspension was shown to attenuate the rate of ROS generation. We have demonstrated that Giardia protects itself from destructive consequences of ROS by maintaining the intracellular pyruvate concentration. Pyruvate recovers Giardia trophozoites from oxidative stress by decreasing the number of DNA breaks that might favor DNA repair.
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Affiliation(s)
- Dibyendu Raj
- Vivekananda College, Thakurpukur, Kolkata-700063, India.,Division of Parasitology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata-700010, India
| | - Punam Chowdhury
- Division of Parasitology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata-700010, India
| | - Rituparna Sarkar
- Division of Parasitology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata-700010, India
| | - Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan
| | - Keinosuke Okamoto
- Collaborative Research Center of Okayama University for Infectious Diseases in India, Kolkata-700010, India
| | - Shanta Dutta
- Division of Parasitology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata-700010, India
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, School of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Sandipan Ganguly
- Division of Parasitology, National Institute of Cholera and Enteric Diseases, Beliaghata, Kolkata-700010, India
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32
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Ma’ayeh SY, Liu J, Peirasmaki D, Hörnaeus K, Bergström Lind S, Grabherr M, Bergquist J, Svärd SG. Characterization of the Giardia intestinalis secretome during interaction with human intestinal epithelial cells: The impact on host cells. PLoS Negl Trop Dis 2017; 11:e0006120. [PMID: 29228011 PMCID: PMC5739509 DOI: 10.1371/journal.pntd.0006120] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 12/21/2017] [Accepted: 11/17/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Giardia intestinalis is a non-invasive protozoan parasite that causes giardiasis in humans, the most common form of parasite-induced diarrhea. Disease mechanisms are not completely defined and very few virulence factors are known. METHODOLOGY To identify putative virulence factors and elucidate mechanistic pathways leading to disease, we have used proteomics to identify the major excretory-secretory products (ESPs) when Giardia trophozoites of WB and GS isolates (assemblages A and B, respectively) interact with intestinal epithelial cells (IECs) in vitro. FINDINGS The main parts of the IEC and parasite secretomes are constitutively released proteins, the majority of which are associated with metabolism but several proteins are released in response to their interaction (87 and 41 WB and GS proteins, respectively, 76 and 45 human proteins in response to the respective isolates). In parasitized IECs, the secretome profile indicated effects on the cell actin cytoskeleton and the induction of immune responses whereas that of Giardia showed anti-oxidation, proteolysis (protease-associated) and induction of encystation responses. The Giardia secretome also contained immunodominant and glycosylated proteins as well as new candidate virulence factors and assemblage-specific differences were identified. A minor part of Giardia ESPs had signal peptides (29% for both isolates) and extracellular vesicles were detected in the ESPs fractions, suggesting alternative secretory pathways. Microscopic analyses showed ESPs binding to IECs and partial internalization. Parasite ESPs reduced ERK1/2 and P38 phosphorylation and NF-κB nuclear translocation. Giardia ESPs altered gene expression in IECs, with a transcriptional profile indicating recruitment of immune cells via chemokines, disturbances in glucose homeostasis, cholesterol and lipid metabolism, cell cycle and induction of apoptosis. CONCLUSIONS This is the first study identifying Giardia ESPs and evaluating their effects on IECs. It highlights the importance of host and parasite ESPs during interactions and reveals the intricate cellular responses that can explain disease mechanisms and attenuated inflammatory responses during giardiasis.
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Affiliation(s)
- Showgy Y. Ma’ayeh
- Department of Cell and Molecular Biology, Uppsala University, BMC, Uppsala, Sweden
| | - Jingyi Liu
- Department of Cell and Molecular Biology, Uppsala University, BMC, Uppsala, Sweden
| | - Dimitra Peirasmaki
- Department of Cell and Molecular Biology, Uppsala University, BMC, Uppsala, Sweden
| | - Katarina Hörnaeus
- Department of Chemistry-BMC, Analytical Chemistry, Uppsala University, Uppsala, Sweden
| | - Sara Bergström Lind
- Department of Chemistry-BMC, Analytical Chemistry, Uppsala University, Uppsala, Sweden
| | - Manfred Grabherr
- Department of Medical Biochemsitry and Microbiology, BMC, Uppsala, Sweden
| | - Jonas Bergquist
- Department of Chemistry-BMC, Analytical Chemistry, Uppsala University, Uppsala, Sweden
| | - Staffan G. Svärd
- Department of Cell and Molecular Biology, Uppsala University, BMC, Uppsala, Sweden
- * E-mail:
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33
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Cacciò SM, Lalle M, Svärd SG. Host specificity in the Giardia duodenalis species complex. INFECTION GENETICS AND EVOLUTION 2017; 66:335-345. [PMID: 29225147 DOI: 10.1016/j.meegid.2017.12.001] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 12/01/2017] [Accepted: 12/02/2017] [Indexed: 12/15/2022]
Abstract
Giardia duodenalis is a unicellular flagellated parasite that infects the gastrointestinal tract of a wide range of mammalian species, including humans. Investigations of protein and DNA polymorphisms revealed that G. duodenalis should be considered as a species complex, whose members, despite being morphologically indistinguishable, can be classified into eight groups, or Assemblages, separated by large genetic distances. Assemblages display various degree of host specificity, with Assemblages A and B occurring in humans and many other hosts, Assemblage C and D in canids, Assemblage E in hoofed animals, Assemblage F in cats, Assemblage G in rodents, and Assemblage H in pinnipeds. The factors determining host specificity are only partially understood, and clearly involve both the host and the parasite. Here, we review the results of in vitro and in vivo experiments, and clinical observations to highlight relevant biological and genetic differences between Assemblages, with a focus on human infection.
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Affiliation(s)
- Simone M Cacciò
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy.
| | - Marco Lalle
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Staffan G Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
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34
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Fink MY, Singer SM. The Intersection of Immune Responses, Microbiota, and Pathogenesis in Giardiasis. Trends Parasitol 2017; 33:901-913. [PMID: 28830665 DOI: 10.1016/j.pt.2017.08.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 07/18/2017] [Accepted: 08/01/2017] [Indexed: 02/07/2023]
Abstract
Giardia lamblia is one of the most common infectious protozoans in the world. Giardia rarely causes severe life-threatening diarrhea, and may even have a slight protective effect in this regard, but it is a major contributor to malnutrition and growth faltering in children in the developing world. Giardia infection also appears to be a significant risk factor for postinfectious irritable bowel and chronic fatigue syndromes. In this review we highlight recent work focused on the impact of giardiasis and the mechanisms that contribute to the various outcomes of this infection, including changes in the composition of the microbiota, activation of immune responses, and immunopathology.
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Affiliation(s)
- Marc Y Fink
- Department of Biology, Georgetown University, Washington, DC, USA
| | - Steven M Singer
- Department of Biology, Georgetown University, Washington, DC, USA.
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35
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Pham JK, Nosala C, Scott EY, Nguyen KF, Hagen KD, Starcevich HN, Dawson SC. Transcriptomic Profiling of High-Density Giardia Foci Encysting in the Murine Proximal Intestine. Front Cell Infect Microbiol 2017; 7:227. [PMID: 28620589 PMCID: PMC5450421 DOI: 10.3389/fcimb.2017.00227] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/16/2017] [Indexed: 12/15/2022] Open
Abstract
Giardia is a highly prevalent, understudied protistan parasite causing significant diarrheal disease worldwide. Its life cycle consists of two stages: infectious cysts ingested from contaminated food or water sources, and motile trophozoites that colonize and attach to the gut epithelium, later encysting to form new cysts that are excreted into the environment. Current understanding of parasite physiology in the host is largely inferred from transcriptomic studies using Giardia grown axenically or in co-culture with mammalian cell lines. The dearth of information about the diversity of host-parasite interactions occurring within distinct regions of the gastrointestinal tract has been exacerbated by a lack of methods to directly and non-invasively interrogate disease progression and parasite physiology in live animal hosts. By visualizing Giardia infections in the mouse gastrointestinal tract using bioluminescent imaging (BLI) of tagged parasites, we recently showed that parasites colonize the gut in high-density foci. Encystation is initiated in these foci throughout the entire course of infection, yet how the physiology of parasites within high-density foci in the host gut differs from that of cells in laboratory culture is unclear. Here we use BLI to precisely select parasite samples from high-density foci in the proximal intestine to interrogate in vivo Giardia gene expression in the host. Relative to axenic culture, we noted significantly higher expression (>10-fold) of oxidative stress, membrane transporter, and metabolic and structural genes associated with encystation in the high-density foci. These differences in gene expression within parasite foci in the host may reflect physiological changes associated with high-density growth in localized regions of the gut. We also identified and verified six novel cyst-specific proteins, including new components of the cyst wall that were highly expressed in these foci. Our in vivo transcriptome data support an emerging view that parasites encyst early in localized regions in the gut, possibly as a consequence of nutrient limitation, and also impact local metabolism and physiology.
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Affiliation(s)
- Jonathan K Pham
- Department of Microbiology and Molecular Genetics, University of California, DavisDavis, CA, United States
| | - Christopher Nosala
- Department of Microbiology and Molecular Genetics, University of California, DavisDavis, CA, United States
| | - Erica Y Scott
- Department of Animal Science, University of California, DavisDavis, CA, United States
| | - Kristofer F Nguyen
- Department of Microbiology and Molecular Genetics, University of California, DavisDavis, CA, United States
| | - Kari D Hagen
- Department of Microbiology and Molecular Genetics, University of California, DavisDavis, CA, United States
| | - Hannah N Starcevich
- Department of Microbiology and Molecular Genetics, University of California, DavisDavis, CA, United States
| | - Scott C Dawson
- Department of Microbiology and Molecular Genetics, University of California, DavisDavis, CA, United States
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36
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The Architecture of Thiol Antioxidant Systems among Invertebrate Parasites. Molecules 2017; 22:molecules22020259. [PMID: 28208651 PMCID: PMC6155587 DOI: 10.3390/molecules22020259] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 02/03/2017] [Indexed: 01/14/2023] Open
Abstract
The use of oxygen as the final electron acceptor in aerobic organisms results in an improvement in the energy metabolism. However, as a byproduct of the aerobic metabolism, reactive oxygen species are produced, leaving to the potential risk of an oxidative stress. To contend with such harmful compounds, living organisms have evolved antioxidant strategies. In this sense, the thiol-dependent antioxidant defense systems play a central role. In all cases, cysteine constitutes the major building block on which such systems are constructed, being present in redox substrates such as glutathione, thioredoxin, and trypanothione, as well as at the catalytic site of a variety of reductases and peroxidases. In some cases, the related selenocysteine was incorporated at selected proteins. In invertebrate parasites, antioxidant systems have evolved in a diversity of both substrates and enzymes, representing a potential area in the design of anti-parasite strategies. The present review focus on the organization of the thiol-based antioxidant systems in invertebrate parasites. Differences between these taxa and its final mammal host is stressed. An understanding of the antioxidant defense mechanisms in this kind of parasites, as well as their interactions with the specific host is crucial in the design of drugs targeting these organisms.
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Divergent Transcriptional Responses to Physiological and Xenobiotic Stress in Giardia duodenalis. Antimicrob Agents Chemother 2016; 60:6034-45. [PMID: 27458219 DOI: 10.1128/aac.00977-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/19/2016] [Indexed: 12/22/2022] Open
Abstract
Understanding how parasites respond to stress can help to identify essential biological processes. Giardia duodenalis is a parasitic protist that infects the human gastrointestinal tract and causes 200 to 300 million cases of diarrhea annually. Metronidazole, a major antigiardial drug, is thought to cause oxidative damage within the infective trophozoite form. However, treatment efficacy is suboptimal, due partly to metronidazole-resistant infections. To elucidate conserved and stress-specific responses, we calibrated sublethal metronidazole, hydrogen peroxide, and thermal stresses to exert approximately equal pressure on trophozoite growth and compared transcriptional responses after 24 h of exposure. We identified 252 genes that were differentially transcribed in response to all three stressors, including glycolytic and DNA repair enzymes, a mitogen-activated protein (MAP) kinase, high-cysteine membrane proteins, flavin adenine dinucleotide (FAD) synthetase, and histone modification enzymes. Transcriptional responses appeared to diverge according to physiological or xenobiotic stress. Downregulation of the antioxidant system and α-giardins was observed only under metronidazole-induced stress, whereas upregulation of GARP-like transcription factors and their subordinate genes was observed in response to hydrogen peroxide and thermal stressors. Limited evidence was found in support of stress-specific response elements upstream of differentially transcribed genes; however, antisense derepression and differential regulation of RNA interference machinery suggest multiple epigenetic mechanisms of transcriptional control.
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Einarsson E, Ma'ayeh S, Svärd SG. An up-date on Giardia and giardiasis. Curr Opin Microbiol 2016; 34:47-52. [PMID: 27501461 DOI: 10.1016/j.mib.2016.07.019] [Citation(s) in RCA: 218] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/27/2016] [Accepted: 07/27/2016] [Indexed: 12/11/2022]
Abstract
Giardia intestinalis is a non-invasive protozoan parasite infecting the upper small intestine causing acute, watery diarrhea or giardiasis in 280 million people annually. Asymptomatic infections are equally common and recent data have suggested that infections even can be protective against other diarrheal diseases. Most symptomatic infections resolve spontaneously but infections can lead to chronic disease and treatment failures are becoming more common world-wide. Giardia infections can also result in irritable bowel syndrome (IBS) and food allergies after resolution. Until recently not much was known about the mechanism of giardiasis or the cause of post-giardiasis syndromes and treatment failures, but here we will describe the recent progress in these areas.
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Affiliation(s)
- Elin Einarsson
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala University, SE-751 24 Uppsala, Sweden
| | - Showgy Ma'ayeh
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala University, SE-751 24 Uppsala, Sweden
| | - Staffan G Svärd
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala University, SE-751 24 Uppsala, Sweden.
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Antioxidant defence systems in the protozoan pathogen Giardia intestinalis. Mol Biochem Parasitol 2016; 206:56-66. [DOI: 10.1016/j.molbiopara.2015.12.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/26/2015] [Accepted: 12/01/2015] [Indexed: 01/03/2023]
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Ansell BRE, McConville MJ, Baker L, Korhonen PK, Young ND, Hall RS, Rojas CAA, Svärd SG, Gasser RB, Jex AR. Time-Dependent Transcriptional Changes in Axenic Giardia duodenalis Trophozoites. PLoS Negl Trop Dis 2015; 9:e0004261. [PMID: 26636323 PMCID: PMC4670223 DOI: 10.1371/journal.pntd.0004261] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 11/03/2015] [Indexed: 12/27/2022] Open
Abstract
Giardia duodenalis is the most common gastrointestinal protozoan parasite of humans and a significant contributor to the global burden of both diarrheal disease and post-infectious chronic disorders. Although G. duodenalis can be cultured axenically, significant gaps exist in our understanding of the molecular biology and metabolism of this pathogen. The present study employed RNA sequencing to characterize the mRNA transcriptome of G. duodenalis trophozoites in axenic culture, at log (48 h of growth), stationary (60 h), and declining (96 h) growth phases. Using ~400-times coverage of the transcriptome, we identified 754 differentially transcribed genes (DTGs), mainly representing two large DTG groups: 438 that were down-regulated in the declining phase relative to log and stationary phases, and 281 that were up-regulated. Differential transcription of prominent antioxidant and glycolytic enzymes implicated oxygen tension as a key factor influencing the transcriptional program of axenic trophozoites. Systematic bioinformatic characterization of numerous DTGs encoding hypothetical proteins of unknown function was achieved using structural homology searching. This powerful approach greatly informed the differential transcription analysis and revealed putative novel antioxidant-coding genes, and the presence of a near-complete two-component-like signaling system that may link cytosolic redox or metabolite sensing to the observed transcriptional changes. Motif searching applied to promoter regions of the two large DTG groups identified different putative transcription factor-binding motifs that may underpin global transcriptional regulation. This study provides new insights into the drivers and potential mediators of transcriptional variation in axenic G. duodenalis and provides context for static transcriptional studies. Giardia is the most common gastrointestinal protozoan parasite of humans. This parasite causes diarrheal disease and is correlated with post-infectious conditions such as irritable bowel syndrome. In the absence of a vaccine, treatment is limited to drugs such as metronidazole, against which clinical resistance is reported. Effective control of Giardia requires a detailed understanding of its biology, and in turn, complete characterization of the standard in vitro culture system. Using RNA sequencing assisted by informatics to functionally annotate hypothetical proteins, we investigated transcriptional changes in axenic Giardia trophozoites at three growth phases over 96 hours. We found two large groups of differentially transcribed genes that indicate changes in the antioxidant system and central carbon metabolism over time. A putative novel signaling pathway may act together with putative transcription factor-binding motifs to regulate these transcriptional changes. Our results suggest that dissolved oxygen in Giardia culture medium may cause oxidative stress early during in vitro growth and that oxygen depletion may limit the efficiency of glycolysis in the declining phase. This work enhances our understanding of the transcriptional flexibility and metabolism of Giardia in vitro.
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Affiliation(s)
- Brendan R. E. Ansell
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
| | - Malcolm J. McConville
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Louise Baker
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Pasi K. Korhonen
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Neil D. Young
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Ross S. Hall
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Cristian A. A. Rojas
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Staffan G. Svärd
- Department of Cell & Molecular Biology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Robin B. Gasser
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Aaron R. Jex
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
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