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Hagen KD, Hart CJS, McInally SG, Dawson SC. Harnessing the power of new genetic tools to illuminate Giardia biology and pathogenesis. Genetics 2024; 227:iyae038. [PMID: 38626297 PMCID: PMC11151923 DOI: 10.1093/genetics/iyae038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 02/19/2024] [Indexed: 04/18/2024] Open
Abstract
Giardia is a prevalent single-celled microaerophilic intestinal parasite causing diarrheal disease and significantly impacting global health. Double diploid (essentially tetraploid) Giardia trophozoites have presented a formidable challenge to the development of molecular genetic tools to interrogate gene function. High sequence divergence and the high percentage of hypothetical proteins lacking homology to proteins in other eukaryotes have limited our understanding of Giardia protein function, slowing drug target validation and development. For more than 25 years, Giardia A and B assemblages have been readily amenable to transfection with plasmids or linear DNA templates. Here, we highlight the utility and power of genetic approaches developed to assess protein function in Giardia, with particular emphasis on the more recent clustered regularly interspaced palindromic repeats/Cas9-based methods for knockdowns and knockouts. Robust and reliable molecular genetic approaches are fundamental toward the interrogation of Giardia protein function and evaluation of druggable targets. New genetic approaches tailored for the double diploid Giardia are imperative for understanding Giardia's unique biology and pathogenesis.
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Affiliation(s)
- Kari D Hagen
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616, USA
| | - Christopher J S Hart
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616, USA
| | - Shane G McInally
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA 01609, USA
| | - Scott C Dawson
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616, USA
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2
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Kim J, Park EA, Shin MY, Park SJ. Identification of target genes regulated by encystation-induced transcription factor Myb2 using knockout mutagenesis in Giardia lamblia. Parasit Vectors 2022; 15:360. [PMID: 36207732 PMCID: PMC9547401 DOI: 10.1186/s13071-022-05489-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 09/16/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Encystation is one of the two processes comprising the life cycle of Giardia lamblia, a protozoan pathogen with tetraploid genome. Giardia lamblia Myb2 (GlMyb2) is a distinct encystation-induced transcription factor whose binding sites are found in the promoter regions of many encystation-induced genes, including its own. METHODS Two sequential CRISPR/Cas9 experiments were performed to remove four glmyb2 alleles. The expression level of G. lamblia cyst wall protein 1 (GlCWP1), a well-known target gene of GlMyb2, was measured via western blotting and immunofluorescence assays. Chromatin immunoprecipitation experiments using anti-GlMyb2 antibodies were performed on the encysting G. lamblia cells. Quantitative real-time PCR was performed to confirm an expression of candidate GlMyb2-regulated genes by comparing the transcript level for each target candidate in wild-type and knockout mutant Giardia. The promoter region of glcwp1 was analyzed via deletion and point mutagenesis of the putative GlMyb2 binding sites in luciferase reporters. RESULTS Characterization of the null glmyb2 mutant indicated loss of functions related to encystation, i.e. cyst formation, and expression of GlCWP1. The addition of the wild-type glmyb2 gene to the null mutant restored the defects in encystation. Chromatin immunoprecipitation experiments revealed dozens of target genes. Nineteen genes were confirmed as GlMyb2 regulons, which include the glmyb2 gene, six for cyst wall proteins, five for signal transduction, two for transporter, two for metabolic enzymes, and three with unknown functions. Detailed analysis on the promoter region of glcwp1 defined three GlMyb2 binding sites important in its encystation-induced expression. CONCLUSIONS Our data confirm that GlMyb2 acts as a transcription activator especially during encystation by comparing the glmyb2 knockout mutant with the wild type. Further investigation using glmyb2 null mutant will provide knowledge regarding transcriptional apparatus required for the encystation process of G. lamblia.
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Affiliation(s)
- Juri Kim
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul, 03722 Korea
| | - Eun-Ah Park
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul, 03722 Korea
| | - Mee Young Shin
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul, 03722 Korea
| | - Soon-Jung Park
- Department of Environmental Medical Biology and Institute of Tropical Medicine, Yonsei University College of Medicine, Seoul, 03722 Korea
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3
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Comprehensive characterization of Cysteine-rich protein-coding genes of Giardia lamblia and their role during antigenic variation. Genomics 2022; 114:110462. [PMID: 35998788 DOI: 10.1016/j.ygeno.2022.110462] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/15/2022] [Accepted: 08/17/2022] [Indexed: 11/21/2022]
Abstract
Giardia lamblia encodes several families of cysteine-rich proteins, including the Variant-specific Surface Proteins (VSPs) involved in the process of antigenic variation. Their characteristics, definition and relationships are still controversial. An exhaustive analysis of the Cys-rich families including organization, features, evolution and levels of expression was performed, by combining pattern searches and predictions with massive sequencing techniques. Thus a new classification for Cys-rich proteins, genes and pseudogenes that better describes their involvement in Giardia's biology is presented. Moreover, three novel characteristics exclusive to the VSP genes, comprising an Initiator element/Kozak-like sequence, an extended polyadenylation signal and a unique pattern of mutually exclusive transcript accumulation is presented as well as the finding that High Cysteine Membrane Proteins, upregulated under stress, may protect the parasite during VSP switching. These results allow better interpretation of previous reports providing the basis for further studies of the biology of this early-branching eukaryote.
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Repurposing the Kinase Inhibitor Mavelertinib for Giardiasis Therapy. Antimicrob Agents Chemother 2022; 66:e0001722. [PMID: 35703552 PMCID: PMC9295539 DOI: 10.1128/aac.00017-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A phenotypic screen of the ReFRAME compound library was performed to identify cell-active inhibitors that could be developed as therapeutics for giardiasis. A primary screen against Giardia lamblia GS clone H7 identified 85 cell-active compounds at a hit rate of 0.72%. A cytotoxicity counterscreen against HEK293T cells was carried out to assess hit compound selectivity for further prioritization. Mavelertinib (PF-06747775), a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), was identified as a potential new therapeutic based on indication, activity, and availability after reconfirmation. Mavelertinib has in vitro efficacy against metronidazole-resistant 713-M3 strains. Other EGFR-TKIs screened in follow-up assays exhibited insignificant inhibition of G. lamblia at 5 μM, suggesting that the primary molecular target of mavelertinib may have a different mechanistic binding mode from human EGFR-tyrosine kinase. Mavelertinib, dosed as low as 5 mg/kg of body weight or as high as 50 mg/kg, was efficacious in the acute murine Giardia infection model. These results suggest that mavelertinib merits consideration for repurposing and advancement to giardiasis clinical trials while its analogues are further developed.
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5
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Shih HW, Alas GCM, Paredez AR. A cell-cycle-dependent GARP-like transcriptional repressor regulates the initiation of differentiation in Giardia lamblia. Proc Natl Acad Sci U S A 2022; 119:e2204402119. [PMID: 35613049 PMCID: PMC9295799 DOI: 10.1073/pnas.2204402119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/21/2022] [Indexed: 11/18/2022] Open
Abstract
Transcriptional regulation of differentiation is critical for parasitic pathogens to adapt to environmental changes and regulate transmission. In response to encystation stimuli, Giardia lamblia shifts the distribution of the cell cycle toward G2 and induces the expression of cyst wall proteins (CWPs) within 2 to 4 h, indicating that key regulatory steps occur within the first 4 h of encystation. However, the role of transcription factors (TFs) in encystation has primarily been investigated at later time points. How TFs initiate encystation and link it to the cell cycle remains enigmatic. Here, we systematically screened six putative early up-regulated TFs for nuclear localization, established their dynamic expression profiles, and determined their functional role in regulating encystation. We found a critical repressor, Golden2, ARR-B, Psr-1–like protein 1 (GARP)–like protein 4 (GLP4), that increases rapidly after 30 min of encystation stimuli and down-regulates encystation-specific markers, including CWPs and enzymes in the cyst N-acetylgalactosamine pathway. Depletion of GLP4 increases cyst production. Importantly, we observe that G2+M cells exhibit higher levels of CWP1, resulting from the activation of myeloblastosis domain protein 2 (MYB2), a TF previously linked to encystation in Giardia. GLP4 up-regulation occurs in G1+S cells, suggesting a role in repressing MYB2 and encystation-specific genes in the G1+S phase of the cell cycle. Furthermore, we demonstrate that depletion of GLP4 up-regulates MYB2 and promotes encystation while overexpression of GLP4 down-regulates MYB2 and represses encystation. Together, these results suggest that Giardia employs a dose-dependent transcriptional response that involves the cell-cycle–regulated repressor GLP4 to orchestrate MYB2 and entry into the encystation pathway.
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Affiliation(s)
- Han-Wei Shih
- Department of Biology, University of Washington, Seattle, WA 98195
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6
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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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Holthaus D, Kraft MR, Krug SM, Wolf S, Müller A, Delgado Betancourt E, Schorr M, Holland G, Knauf F, Schulzke JD, Aebischer T, Klotz C. Dissection of Barrier Dysfunction in Organoid-Derived Human Intestinal Epithelia Induced by Giardia duodenalis. Gastroenterology 2022; 162:844-858. [PMID: 34822802 DOI: 10.1053/j.gastro.2021.11.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/15/2021] [Accepted: 11/08/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS The protozoa Giardia duodenalis is a major cause of gastrointestinal illness worldwide, but underlying pathophysiological mechanisms remain obscure, partly due to the absence of adequate cellular models. We aimed at overcoming these limitations and recapitulating the authentic series of pathogenic events in the primary human duodenal tissue by using the human organoid system. METHODS We established a compartmentalized cellular transwell system with electrophysiological and barrier properties akin to duodenal mucosa and dissected the events leading to G. duodenalis-induced barrier breakdown by functional analysis of transcriptional, electrophysiological, and tight junction components. RESULTS Organoid-derived cell layers of different donors showed a time- and parasite load-dependent leak flux indicated by collapse of the epithelial barrier upon G. duodenalis infection. Gene set enrichment analysis suggested major expression changes, including gene sets contributing to ion transport and tight junction structure. Solute carrier family 12 member 2 and cystic fibrosis transmembrane conductance regulator-dependent chloride secretion was reduced early after infection, while changes in the tight junction composition, localization, and structural organization occurred later as revealed by immunofluorescence analysis and freeze fracture electron microscopy. Functionally, barrier loss was linked to the adenosine 3',5'-cyclic monophosphate (cAMP)/protein kinase A-cAMP response element-binding protein signaling pathway. CONCLUSIONS Data suggest a previously unknown sequence of events culminating in intestinal barrier dysfunction upon G. duodenalis infection during which alterations of cellular ion transport were followed by breakdown of the tight junctional complex and loss of epithelial integrity, events involving a cAMP/protein kinase A-cAMP response element-binding protein mechanism. These findings and the newly established organoid-derived model to study G. duodenalis infection may help to explore new options for intervening with disease and infection, in particular relevant for chronic cases of giardiasis.
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Affiliation(s)
- David Holthaus
- Department of Infectious Diseases, Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Martin R Kraft
- Department of Infectious Diseases, Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Susanne M Krug
- Department of Gastroenterology, Rheumatology and Infectious Diseases, Clinical Physiology Nutritional Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Silver Wolf
- MF 1 Bioinformatics, Robert Koch-Institute, Berlin, Germany
| | - Antonia Müller
- Department of Infectious Diseases, Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Estefania Delgado Betancourt
- Department of Infectious Diseases, Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Madeleine Schorr
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Gudrun Holland
- Advanced Light and Electron Microscopy, Centre for Biological Threats and Special Pathogens, Robert Koch-Institute, Berlin, Germany
| | - Felix Knauf
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Joerg-Dieter Schulzke
- Department of Gastroenterology, Rheumatology and Infectious Diseases, Clinical Physiology Nutritional Medicine, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Toni Aebischer
- Department of Infectious Diseases, Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
| | - Christian Klotz
- Department of Infectious Diseases, Unit 16 Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany.
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A Detailed Gene Expression Map of Giardia Encystation. Genes (Basel) 2021; 12:genes12121932. [PMID: 34946882 PMCID: PMC8700996 DOI: 10.3390/genes12121932] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 11/23/2021] [Accepted: 11/26/2021] [Indexed: 12/13/2022] Open
Abstract
Giardia intestinalis is an intestinal protozoan parasite that causes diarrheal infections worldwide. A key process to sustain its chain of transmission is the formation of infectious cysts in the encystation process. We combined deep RNAseq of a broad range of encystation timepoints to produce a high-resolution gene expression map of Giardia encystation. This detailed transcriptomic map of encystation confirmed a gradual change of gene expression along the time course of encystation, showing the most significant gene expression changes during late encystation. Few genes are differentially expressed early in encystation, but the major cyst wall proteins CWP-1 and -2 are highly up-regulated already after 3.5 h encystation. Several transcription factors are sequentially up-regulated throughout the process, but many up-regulated genes at 7, 10, and 14 h post-induction of encystation have binding sites in the upstream regions for the Myb2 transcription factor, suggesting that Myb2 is a master regulator of encystation. We observed major changes in gene expression of several meiotic-related genes from 10.5 h of encystation to the cyst stage, and at 17.5 h encystation, there are changes in many different metabolic pathways and protein synthesis. Late encystation, 21 h to cysts, show extensive gene expression changes, most of all in VSP and HCMP genes, which are involved in antigenic variation, and genes involved in chromatin modifications. This high-resolution gene expression map of Giardia encystation will be an important tool in further studies of this important differentiation process.
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9
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Multimodal regulation of encystation in Giardia duodenalis revealed by deep proteomics. Int J Parasitol 2021; 51:809-824. [PMID: 34331939 DOI: 10.1016/j.ijpara.2021.01.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 12/24/2020] [Accepted: 01/07/2021] [Indexed: 12/21/2022]
Abstract
Cyst formation in the parasitic protist Giardia duodenalis is critical to its transmission. Existing proteomic data quantifies only 17% of coding genes transcribed during encystation and does not cover the complete process from trophozoite to mature cyst. Using high-resolution mass spectrometry, we have quantified proteomic changes across encystation and compared this with published transcriptomic data. We reproducibly identified 3863 (64.5% of Giardia proteins) and quantified 3382 proteins (56.5% of Giardia proteins) over standard trophozoite growth (TY), during low-bile encystation priming (LB), 16 h into encystation (EC), and at cyst maturation (C). This work provides the first known expanded observation of encystation at the proteomic level and triples the coverage of previous encystation proteomes. One-third (1169 proteins) of the quantified proteome is differentially expressed in the mature cyst relative to the trophozoite, including proteasomal machinery, metabolic pathways, and secretory proteins. Changes in lipid metabolism indicated a shift in lipid species dependency during encystation. Consistent with this, we identified the first, putative lipid transporters in this species, representing the steroidogenic acute regulatory protein-related lipid transfer (StARkin), oxysterol binding protein related protein (ORP/Osh) and glycosphingolipid transfer protein (GLTP) families, and follow their differential expression over cyst formation. Lastly, we undertook correlation analyses of the transcriptome and proteome of trophozoites and cysts, and found evidence of post-transcriptional regulation of key protein classes (RNA binding proteins) and stage-specific genes (encystation markers) implicating translation-repression in encystation. We provide the most extensive proteomic analysis of encystation in Giardia to date and the first known exploration across its complete duration. This work identifies encystation as highly coordinated, involving major changes in proteostasis, metabolism and membrane dynamics, and indicates a potential role for post-transcriptional regulation, mediated through RNA-binding proteins. Together our work provides a valuable resource for Giardia research and the development of transmission-blocking anti-giardials.
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Real-Time PCR for Molecular Detection of Zoonotic and Non-Zoonotic Giardia spp. in Wild Rodents. Microorganisms 2021; 9:microorganisms9081610. [PMID: 34442688 PMCID: PMC8398015 DOI: 10.3390/microorganisms9081610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/06/2021] [Accepted: 07/07/2021] [Indexed: 12/14/2022] Open
Abstract
Giardiasis in humans is a gastrointestinal disease transmitted by the potentially zoonotic Giardia duodenalis genotypes (assemblages) A and B. Small wild rodents such as mice and voles are discussed as potential reservoirs for G. duodenalis but are predominantly populated by the two rodent species Giardia microti and Giardia muris. Currently, the detection of zoonotic and non-zoonotic Giardia species and genotypes in these animals relies on cumbersome PCR and sequencing approaches of genetic marker genes. This hampers the risk assessment of potential zoonotic Giardia transmissions by these animals. Here, we provide a workflow based on newly developed real-time PCR schemes targeting the small ribosomal RNA multi-copy gene locus to distinguish G. muris, G. microti and G. duodenalis infections. For the identification of potentially zoonotic G. duodenalis assemblage types A and B, an established protocol targeting the single-copy gene 4E1-HP was used. The assays were specific for the distinct Giardia species or genotypes and revealed an analytical sensitivity of approximately one or below genome equivalent for the multi-copy gene and of about 10 genome equivalents for the single-copy gene. Retesting a biobank of small rodent samples confirmed the specificity. It further identified the underlying Giardia species in four out of 11 samples that could not be typed before by PCR and sequencing. The newly developed workflow has the potential to facilitate the detection of potentially zoonotic and non-zoonotic Giardia species in wild rodents.
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12
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Michaels SA, Shih HW, Zhang B, Navaluna ED, Zhang Z, Ranade RM, Gillespie JR, Merritt EA, Fan E, Buckner FS, Paredez AR, Ojo KK. Methionyl-tRNA synthetase inhibitor has potent in vivo activity in a novel Giardia lamblia luciferase murine infection model. J Antimicrob Chemother 2021; 75:1218-1227. [PMID: 32011682 DOI: 10.1093/jac/dkz567] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 11/29/2019] [Accepted: 12/17/2019] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Methionyl-tRNA synthetase (MetRS) inhibitors are under investigation for the treatment of intestinal infections caused by Giardia lamblia. OBJECTIVES To properly analyse the therapeutic potential of the MetRS inhibitor 1717, experimental tools including a robust cell-based assay and a murine model of infection were developed based on novel strains of G. lamblia that employ luciferase reporter systems to quantify viable parasites. METHODS Systematic screening of Giardia-specific promoters and luciferase variants led to the development of a strain expressing the click beetle green luciferase. Further modifying this strain to express NanoLuc created a dual reporter strain capable of quantifying parasites in both the trophozoite and cyst stages. These strains were used to develop a high-throughput cell assay and a mouse infection model. A library of MetRS inhibitors was screened in the cell assay and Compound-1717 was tested for efficacy in the mouse infection model. RESULTS Cell viability in in vitro compound screens was quantified via bioluminescence readouts while infection loads in mice were monitored with non-invasive whole-animal imaging and faecal analysis. Compound-1717 was effective in clearing mice of Giardia infection in 3 days at varying doses, which was supported by data from enzymatic and phenotypic cell assays. CONCLUSIONS The new in vitro and in vivo assays based on luciferase expression by engineered G. lamblia strains are useful for the discovery and development of new therapeutics for giardiasis. MetRS inhibitors, as validated by Compound-1717, have promising anti-giardiasis properties that merit further study as alternative therapeutics.
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Affiliation(s)
- Samantha A Michaels
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Reemerging Infectious Diseases (CERID), University of Washington, Seattle, WA 98109, USA
| | - Han-Wei Shih
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Bailin Zhang
- Department of Biology, University of Washington, Seattle, WA 98195, USA
| | - Edelmar D Navaluna
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Reemerging Infectious Diseases (CERID), University of Washington, Seattle, WA 98109, USA
| | - Zhongsheng Zhang
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Ranae M Ranade
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Reemerging Infectious Diseases (CERID), University of Washington, Seattle, WA 98109, USA
| | - J Robert Gillespie
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Reemerging Infectious Diseases (CERID), University of Washington, Seattle, WA 98109, USA
| | - Ethan A Merritt
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Erkang Fan
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Frederick S Buckner
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Reemerging Infectious Diseases (CERID), University of Washington, Seattle, WA 98109, USA
| | | | - Kayode K Ojo
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Reemerging Infectious Diseases (CERID), University of Washington, Seattle, WA 98109, USA
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13
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Thomas EB, Sutanto R, Johnson RS, Shih HW, Alas GCM, Krtková J, MacCoss MJ, Paredez AR. Staging Encystation Progression in Giardia lamblia Using Encystation-Specific Vesicle Morphology and Associating Molecular Markers. Front Cell Dev Biol 2021; 9:662945. [PMID: 33987184 PMCID: PMC8111296 DOI: 10.3389/fcell.2021.662945] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/15/2021] [Indexed: 01/24/2023] Open
Abstract
Differentiation into environmentally resistant cysts is required for transmission of the ubiquitous intestinal parasite Giardia lamblia. Encystation in Giardia requires the production, processing and transport of Cyst Wall Proteins (CWPs) in developmentally induced, Golgi-like, Encystation Specific Vesicles (ESVs). Progress through this trafficking pathway can be followed by tracking CWP localization over time. However, there is no recognized system to distinguish the advancing stages of this process which can complete at variable rates depending on how encystation is induced. Here, we propose a staging system for encysting Giardia based on the morphology of CWP1-stained ESVs. We demonstrate the molecular distinctiveness of maturing ESVs at these stages by following GlRab GTPases through encystation. Previously, we established that Giardia’s sole Rho family GTPase, GlRac, associates with ESVs and has a role in regulating their maturation and the secretion of their cargo. As a proof of principle, we delineate the relationship between GlRac and ESV stages. Through proteomic studies, we identify putative interactors of GlRac that could be used as additional ESV stage markers. This staging system provides a common descriptor of ESV maturation regardless of the source of encysting cells. Furthermore, the identified set of molecular markers for ESV stages will be a powerful tool for characterizing trafficking mutants that impair ESV maturation and morphology.
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Affiliation(s)
- Elizabeth B Thomas
- Department of Biology, University of Washington, Seattle, WA, United States
| | - Renaldo Sutanto
- Department of Biology, University of Washington, Seattle, WA, United States.,Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, United States
| | - Richard S Johnson
- Department of Genome Sciences, University of Washington, Seattle, WA, United States
| | - Han-Wei Shih
- Department of Biology, University of Washington, Seattle, WA, United States
| | - Germain C M Alas
- Department of Biology, University of Washington, Seattle, WA, United States
| | - Jana Krtková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Michael J MacCoss
- Department of Genome Sciences, University of Washington, Seattle, WA, United States
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14
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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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15
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Eukaryote-conserved histone post-translational modification landscape in Giardia duodenalis revealed by mass spectrometry. Int J Parasitol 2020; 51:225-239. [PMID: 33275945 DOI: 10.1016/j.ijpara.2020.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/01/2020] [Accepted: 09/22/2020] [Indexed: 12/15/2022]
Abstract
Diarrheal disease caused by Giardia duodenalis is highly prevalent, causing over 200 million cases globally each year. The processes that drive parasite virulence, host immune evasion and transmission involve coordinated gene expression and have been linked to epigenetic regulation. Epigenetic regulatory systems are eukaryote-conserved, including in deep branching excavates such as Giardia, with several studies already implicating histone post-translational modifications in regulation of its pathogenesis and life cycle. However, further insights into Giardia chromatin dynamics have been hindered by a lack of site-specific knowledge of histone modifications. Using mass spectrometry, we have provided the first known molecular map of histone methylation, acetylation and phosphorylation modifications in Giardia core histones. We have identified over 50 previously unreported histone modifications including sites with established roles in epigenetic regulation, and co-occurring modifications indicative of post-translational modification crosstalk. These demonstrate conserved histone modifications in Giardia which are equivalent to many other eukaryotes, and suggest that similar epigenetic mechanisms are in place in this parasite. Further, we used sequence, domain and structural homology to annotate putative histone enzyme networks in Giardia, highlighting representative chromatin modifiers which appear sufficient for identified sites, particularly those from H3 and H4 variants. This study is to our knowledge the first and most comprehensive, complete and accurate view of Giardia histone post-translational modifications to date, and a substantial step towards understanding their associations in parasite development and virulence.
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16
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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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17
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Xu F, Jiménez-González A, Einarsson E, Ástvaldsson Á, Peirasmaki D, Eckmann L, Andersson JO, Svärd SG, Jerlström-Hultqvist J. The compact genome of Giardia muris reveals important steps in the evolution of intestinal protozoan parasites. Microb Genom 2020; 6:mgen000402. [PMID: 32618561 PMCID: PMC7641422 DOI: 10.1099/mgen.0.000402] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 06/16/2020] [Indexed: 01/05/2023] Open
Abstract
Diplomonad parasites of the genus Giardia have adapted to colonizing different hosts, most notably the intestinal tract of mammals. The human-pathogenic Giardia species, Giardia intestinalis, has been extensively studied at the genome and gene expression level, but no such information is available for other Giardia species. Comparative data would be particularly valuable for Giardia muris, which colonizes mice and is commonly used as a prototypic in vivo model for investigating host responses to intestinal parasitic infection. Here we report the draft-genome of G. muris. We discovered a highly streamlined genome, amongst the most densely encoded ever described for a nuclear eukaryotic genome. G. muris and G. intestinalis share many known or predicted virulence factors, including cysteine proteases and a large repertoire of cysteine-rich surface proteins involved in antigenic variation. Different to G. intestinalis, G. muris maintains tandem arrays of pseudogenized surface antigens at the telomeres, whereas intact surface antigens are present centrally in the chromosomes. The two classes of surface antigens engage in genetic exchange. Reconstruction of metabolic pathways from the G. muris genome suggest significant metabolic differences to G. intestinalis. Additionally, G. muris encodes proteins that might be used to modulate the prokaryotic microbiota. The responsible genes have been introduced in the Giardia genus via lateral gene transfer from prokaryotic sources. Our findings point to important evolutionary steps in the Giardia genus as it adapted to different hosts and it provides a powerful foundation for mechanistic exploration of host-pathogen interaction in the G. muris-mouse pathosystem.
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Affiliation(s)
- Feifei Xu
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala Universitet, SE-751 24 Uppsala, Sweden
| | | | - Elin Einarsson
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala Universitet, SE-751 24 Uppsala, Sweden
- Present address: Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Ásgeir Ástvaldsson
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala Universitet, SE-751 24 Uppsala, Sweden
- Present address: Department of Microbiology, National Veterinary Institute, Uppsala, Sweden
| | - Dimitra Peirasmaki
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala Universitet, SE-751 24 Uppsala, Sweden
- Present address: Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden
| | - Lars Eckmann
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Jan O. Andersson
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala Universitet, SE-751 24 Uppsala, Sweden
| | - Staffan G. Svärd
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala Universitet, SE-751 24 Uppsala, Sweden
| | - Jon Jerlström-Hultqvist
- Department of Cell and Molecular Biology, BMC, Box 596, Uppsala Universitet, SE-751 24 Uppsala, Sweden
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18
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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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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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Lalle M, Fiorillo A. The protein 14-3-3: A functionally versatile molecule in Giardia duodenalis. ADVANCES IN PARASITOLOGY 2019; 106:51-103. [PMID: 31630760 DOI: 10.1016/bs.apar.2019.08.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Giardia duodenalis is a cosmopolitan zoonotic protozoan parasite causing giardiasis, one of the most common diarrhoeal diseases in human and animals. Beyond its public health relevance, Giardia represents a valuable and fascinating model microorganism. The deep-branching phylogenetic position of Giardia, its simple life cycle and its minimalistic genomic and cellular organization provide a unique opportunity to define basal and "ancestral" eukaryotic functions. The eukaryotic 14-3-3 protein family represents a distinct example of phosphoserine/phosphothreonine-binding proteins. The extended network of protein-protein interactions established by 14-3-3 proteins place them at the crossroad of multiple signalling pathways that regulate physiological and pathological cellular processes. Despite the remarkable insight on 14-3-3 protein in different organisms, from yeast to humans, so far little attention was given to the study of this protein in protozoan parasites. However, in the last years, research efforts have provided evidences on unique properties of the single 14-3-3 protein of Giardia and on its association in key aspects of Giardia life cycle. In the first part of this chapter, a general overview of the features commonly shared among 14-3-3 proteins in different organisms (i.e. structure, target recognition, mode of action and regulatory mechanisms) is included. The second part focus on the current knowledge on the biochemistry and biology of the Giardia 14-3-3 protein and on the possibility to use this protein as target to propose new strategies for developing innovative antigiardial therapy.
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Affiliation(s)
- Marco Lalle
- Department of Infectious Diseases, European Union Reference Laboratory for Parasites, Istituto Superiore di Sanità, Rome, Italy.
| | - Annarita Fiorillo
- Department of Biochemical Sciences "A. Rossi Fanelli", Sapienza University of Rome, Rome, Italy
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21
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Liu J, Svärd SG, Klotz C. Giardia intestinalis cystatin is a potent inhibitor of papain, parasite cysteine proteases and, to a lesser extent, human cathepsin B. FEBS Lett 2019; 593:1313-1325. [PMID: 31077354 DOI: 10.1002/1873-3468.13433] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 04/16/2019] [Accepted: 05/04/2019] [Indexed: 11/09/2022]
Abstract
Cystatins are important regulators of papain-like cysteine proteases. In the protozoan parasite Giardia intestinalis, papain-like cysteine proteases play an essential role in the parasite's biology and pathogenicity. Here, we characterized a cysteine protease inhibitor of G. intestinalis that belongs to type-I-cystatins. The parasite cystatin is shown to be a strong inhibitor of papain (Ki ≈ 0.3 nm) and three parasite cysteine proteases (CP14019, CP16160 and CP16779, Ki ≈ 0.9-5.8 nm), but a weaker inhibitor of human cathepsin B (Ki ≈ 79.9 nm). The protein localizes mainly in the cytoplasm. Together, these data suggest that cystatin of G. intestinalis plays a role in the regulation of cysteine protease activities in the parasite and, possibly, in the interaction with the host.
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Affiliation(s)
- Jingyi Liu
- Department of Cell and Molecular Biology, BMC, Uppsala University, Sweden
| | - Staffan G Svärd
- Department of Cell and Molecular Biology, BMC, Uppsala University, Sweden
| | - Christian Klotz
- Department of Mycotic and Parasitic Agents and Mycobacteria (FG16), Robert Koch-Institute, Berlin, Germany
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22
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McInally SG, Hagen KD, Nosala C, Williams J, Nguyen K, Booker J, Jones K, Dawson SC. Robust and stable transcriptional repression in Giardia using CRISPRi. Mol Biol Cell 2018; 30:119-130. [PMID: 30379614 PMCID: PMC6337905 DOI: 10.1091/mbc.e18-09-0605] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Giardia lamblia is a binucleate protistan parasite causing significant diarrheal disease worldwide. An inability to target Cas9 to both nuclei, combined with the lack of nonhomologous end joining and markers for positive selection, has stalled the adaptation of CRISPR/Cas9-mediated genetic tools for this widespread parasite. CRISPR interference (CRISPRi) is a modification of the CRISPR/Cas9 system that directs catalytically inactive Cas9 (dCas9) to target loci for stable transcriptional repression. Using a Giardia nuclear localization signal to target dCas9 to both nuclei, we developed efficient and stable CRISPRi-mediated transcriptional repression of exogenous and endogenous genes in Giardia. Specifically, CRISPRi knockdown of kinesin-2a and kinesin-13 causes severe flagellar length defects that mirror defects with morpholino knockdown. Knockdown of the ventral disk MBP protein also causes severe structural defects that are highly prevalent and persist in the population more than 5 d longer than defects associated with transient morpholino-based knockdown. By expressing two guide RNAs in tandem to simultaneously knock down kinesin-13 and MBP, we created a stable dual knockdown strain with both flagellar length and disk defects. The efficiency and simplicity of CRISPRi in polyploid Giardia allows rapid evaluation of knockdown phenotypes and highlights the utility of CRISPRi for emerging model systems.
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Affiliation(s)
- S G McInally
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - K D Hagen
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - C Nosala
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - J Williams
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - K Nguyen
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - J Booker
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - K Jones
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
| | - Scott C Dawson
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA 95616
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23
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Hennessey KM, Rogiers IC, Shih HW, Hulverson MA, Choi R, McCloskey MC, Whitman GR, Barrett LK, Merritt EA, Paredez AR, Ojo KK. Screening of the Pathogen Box for inhibitors with dual efficacy against Giardia lamblia and Cryptosporidium parvum. PLoS Negl Trop Dis 2018; 12:e0006673. [PMID: 30080847 PMCID: PMC6095626 DOI: 10.1371/journal.pntd.0006673] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 08/16/2018] [Accepted: 07/09/2018] [Indexed: 12/13/2022] Open
Abstract
There is need for a more efficient cell-based assay amenable to high-throughput drug screening against Giardia lamblia. Here, we report the development of a screening method utilizing G. lamblia engineered to express red-shifted firefly luciferase. Parasite growth and replication were quantified using D-luciferin as a substrate in a bioluminescent read-out plateform. This assay was validated for reproducibility and reliability against the Medicines for Malaria Venture (MMV) Pathogen Box compounds. For G. lamblia, forty-three compounds showed ≥ 75% inhibition of parasite growth in the initial screen (16 μM), with fifteen showing ≥ 95% inhibition. The Pathogen Box was also screened against Nanoluciferase expressing (Nluc) C. parvum, yielding 85 compounds with ≥ 75% parasite growth inhibition at 10 μM, with six showing ≥ 95% inhibition. A representative set of seven compounds with activity against both parasites were further analyzed to determine the effective concentration that causes 50% growth inhibition (EC50) and cytotoxicity against mammalian HepG2 cells. Four of the seven compounds were previously known to be effective in treating either Giardia or Cryptosporidium. The remaining three shared no obvious chemical similarity with any previously characterized anti-parasite diarrheal drugs and offer new medicinal chemistry opportunities for therapeutic development. These results suggest that the bioluminescent assays are suitable for large-scale screening of chemical libraries against both C. parvum and G. lamblia.
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Affiliation(s)
- Kelly M. Hennessey
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Ilse C. Rogiers
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, Washington, United States of America
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Antwerp, Belgium
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Han-Wei Shih
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Matthew A. Hulverson
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, Washington, United States of America
| | - Ryan Choi
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, Washington, United States of America
| | - Molly C. McCloskey
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, Washington, United States of America
| | - Grant R. Whitman
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, Washington, United States of America
| | - Lynn K. Barrett
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, Washington, United States of America
| | - Ethan A. Merritt
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
| | - Alexander R. Paredez
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Kayode K. Ojo
- Department of Medicine, Division of Allergy and Infectious Diseases, Center for Emerging and Re-emerging Infectious Diseases (CERID), University of Washington, Seattle, Washington, United States of America
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24
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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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Ankarklev J, Lebbad M, Einarsson E, Franzén O, Ahola H, Troell K, Svärd SG. A novel high-resolution multilocus sequence typing of Giardia intestinalis Assemblage A isolates reveals zoonotic transmission, clonal outbreaks and recombination. INFECTION GENETICS AND EVOLUTION 2018; 60:7-16. [DOI: 10.1016/j.meegid.2018.02.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 01/30/2018] [Accepted: 02/09/2018] [Indexed: 12/22/2022]
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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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