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Giuliano CJ, Wei KJ, Harling FM, Waldman BS, Farringer MA, Boydston EA, Lan TCT, Thomas RW, Herneisen AL, Sanderlin AG, Coppens I, Dvorin JD, Lourido S. CRISPR-based functional profiling of the Toxoplasma gondii genome during acute murine infection. Nat Microbiol 2024:10.1038/s41564-024-01754-2. [PMID: 38977907 DOI: 10.1038/s41564-024-01754-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 06/07/2024] [Indexed: 07/10/2024]
Abstract
Examining host-pathogen interactions in animals can capture aspects of infection that are obscured in cell culture. Using CRISPR-based screens, we functionally profile the entire genome of the apicomplexan parasite Toxoplasma gondii during murine infection. Barcoded gRNAs enabled bottleneck detection and mapping of population structures within parasite lineages. Over 300 genes with previously unknown roles in infection were found to modulate parasite fitness in mice. Candidates span multiple axes of host-parasite interaction. Rhoptry Apical Surface Protein 1 was characterized as a mediator of host-cell tropism that facilitates repeated invasion attempts. GTP cyclohydrolase I was also required for fitness in mice and druggable through a repurposed compound, 2,4-diamino-6-hydroxypyrimidine. This compound synergized with pyrimethamine against T. gondii and malaria-causing Plasmodium falciparum parasites. This work represents a complete survey of an apicomplexan genome during infection of an animal host and points to novel interfaces of host-parasite interaction.
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Affiliation(s)
| | - Kenneth J Wei
- Whitehead Institute, Cambridge, MA, USA
- Biology Department, MIT, Cambridge, MA, USA
| | | | - Benjamin S Waldman
- Whitehead Institute, Cambridge, MA, USA
- Biology Department, MIT, Cambridge, MA, USA
| | - Madeline A Farringer
- Division of Infectious Diseases, Boston Children's Hospital, Boston, MA, USA
- Biological Sciences in Public Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | | | | | - Raina W Thomas
- Whitehead Institute, Cambridge, MA, USA
- Biology Department, MIT, Cambridge, MA, USA
| | - Alice L Herneisen
- Whitehead Institute, Cambridge, MA, USA
- Biology Department, MIT, Cambridge, MA, USA
| | | | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Jeffrey D Dvorin
- Division of Infectious Diseases, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Sebastian Lourido
- Whitehead Institute, Cambridge, MA, USA.
- Biology Department, MIT, Cambridge, MA, USA.
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2
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Zheng XN, Li TT, Elsheikha HM, Wang M, Sun LX, Wu XJ, Fu BQ, Zhu XQ, Wang JL. GRA47 is important for the morphology and permeability of the parasitophorous vacuole in Toxoplasma gondii. Int J Parasitol 2024:S0020-7519(24)00135-8. [PMID: 38936501 DOI: 10.1016/j.ijpara.2024.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 05/13/2024] [Accepted: 06/20/2024] [Indexed: 06/29/2024]
Abstract
Establishing an intact intracellular parasitophorous vacuole (PV) that enables efficient nutrient uptake and protein trafficking is essential for the survival and proliferation of Toxoplasma gondii. Although the PV membrane (PVM)-localized dense granule protein 17 (GRA17) and GRA23 mediate the permeability of the PVM to small molecules, including nutrient uptake and excretion of metabolic by-products, the molecular mechanism by which T. gondii acquires nutrients remains unclear. In this study, we showed that the secreted protein GRA47 contributed to normal PV morphology, PVM permeability to small molecules, growth, and virulence in T. gondii. Co-immunoprecipitation analysis demonstrated potential interaction of GRA47 with GRA72, and the loss of GRA72 affected PV morphology, parasite growth and infectivity. To investigate the biological relationship among GRA47, GRA72, GRA17 and GRA23, attempts were made to construct strains with double gene deletion and overexpressing strains. Only Δgra23Δgra72 was successfully constructed. This strain exhibited a significant increase in the proportion of aberrant PVs compared with the Δgra23 strain. Overexpressing one of the three related GRAs partially rescued PVs with aberrant morphology in Δgra47, Δgra72 and Δgra17, while the expression of the Plasmodium falciparum PVM protein PfExp2, an ortholog of GRA17 and GRA23, fully rescued the PV morphological defect in all three Δgra strains. These results suggest that these GRA proteins may not be functionally redundant but rather work in different ways to regulate nutrient acquisition. These findings highlight the versatility of the nutrient uptake mechanisms in T. gondii, which may contribute to the parasite's remarkable ability to grow in different cellular niches in a very broad range of hosts.
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Affiliation(s)
- Xiao-Nan Zheng
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Laboratory of Parasitic Diseases, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province 030801, People's Republic of China
| | - Ting-Ting Li
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, Sichuan Province 610213, People's Republic of China
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Meng Wang
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, Sichuan Province 610213, People's Republic of China
| | - Li-Xiu Sun
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, Sichuan Province 610213, People's Republic of China
| | - Xiao-Jing Wu
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Laboratory of Parasitic Diseases, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province 030801, People's Republic of China
| | - Bao-Quan Fu
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, Sichuan Province 610213, People's Republic of China
| | - Xing-Quan Zhu
- Laboratory of Parasitic Diseases, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province 030801, People's Republic of China.
| | - Jin-Lei Wang
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, Sichuan Province 610213, People's Republic of China.
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3
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Lucky AB, Wang C, Li X, Liang X, Muneer A, Miao J. Transforming the CRISPR/dCas9-based gene regulation technique into a forward screening tool in Plasmodium falciparum. iScience 2024; 27:109602. [PMID: 38617559 PMCID: PMC11015506 DOI: 10.1016/j.isci.2024.109602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 02/11/2024] [Accepted: 03/25/2024] [Indexed: 04/16/2024] Open
Abstract
It is a significant challenge to assess the functions of many uncharacterized genes in human malaria parasites. Here, we present a genetic screening tool to assess the contribution of essential genes from Plasmodium falciparum by the conditional CRISPR-/deadCas9-based interference and activation (i/a) systems. We screened both CRISPRi and CRISPRa sets, consisting of nine parasite lines per set targeting nine genes via their respective gRNAs. By conducting amplicon sequencing of gRNA loci, we identified the contribution of each targeted gene to parasite fitness upon drug (artemisinin, chloroquine) and stress (starvation, heat shock) treatment. The screening was highly reproducible, and the screening libraries were easily generated by transfection of mixed plasmids expressing different gRNAs. We demonstrated that this screening is straightforward, robust, and can provide a fast and efficient tool to study essential genes that have long presented a bottleneck in assessing their functions using existing genetic tools.
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Affiliation(s)
- Amuza Byaruhanga Lucky
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
| | - Chengqi Wang
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
| | - Xiaolian Li
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
| | - Xiaoying Liang
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
| | - Azhar Muneer
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
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4
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Bitew MA, Gaete PS, Swale C, Maru P, Contreras JE, Saeij JPJ. Two Toxoplasma gondii putative pore-forming proteins, GRA47 and GRA72, influence small molecule permeability of the parasitophorous vacuole. mBio 2024; 15:e0308123. [PMID: 38380952 PMCID: PMC10936148 DOI: 10.1128/mbio.03081-23] [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: 11/13/2023] [Accepted: 02/01/2024] [Indexed: 02/22/2024] Open
Abstract
Toxoplasma gondii, a medically important intracellular parasite, uses GRA proteins secreted from dense granule organelles to mediate nutrient flux across the parasitophorous vacuole membrane (PVM). GRA17 and GRA23 are known pore-forming proteins on the PVM involved in this process, but the roles of additional proteins have remained largely uncharacterized. We recently identified GRA72 as synthetically lethal with GRA17. Deleting GRA72 produced similar phenotypes to Δgra17 parasites, and computational predictions suggested it forms a pore. To understand how GRA72 functions, we performed immunoprecipitation experiments and identified GRA47 as an interactor of GRA72. Deletion of GRA47 resulted in an aberrant "bubble vacuole" morphology with reduced small molecule permeability, mirroring the phenotype observed in GRA17 and GRA72 knockouts. Structural predictions indicated that GRA47 and GRA72 form heptameric and hexameric pores, respectively, with conserved histidine residues lining the pore. Mutational analysis highlighted the critical role of these histidines for protein functionality. Validation through electrophysiology confirmed alterations in membrane conductance, corroborating their pore-forming capabilities. Furthermore, Δgra47 parasites and parasites expressing GRA47 with a histidine mutation had reduced in vitro proliferation and attenuated virulence in mice. Our findings show the important roles of GRA47 and GRA72 in regulating PVM permeability, thereby expanding the repertoire of potential therapeutic targets against Toxoplasma infections. IMPORTANCE Toxoplasma gondii is a parasite that poses significant health risks to those with impaired immunity. It replicates inside host cells shielded by the PVM, which controls nutrient and waste exchange with the host. GRA72, previously identified as essential in the absence of the GRA17 nutrient channel, is implicated in forming an alternative nutrient channel. Here we found that GRA47 associates with GRA72 and is also important for the PVM's permeability to small molecules. Removal of GRA47 leads to distorted vacuoles and impairs small molecule transport across the PVM, resembling the effects of GRA17 and GRA72 deletions. Structural models suggest GRA47 and GRA72 form distinct pore structures, with a pore-lining histidine critical to their function. Toxoplasma strains lacking GRA47 or those with a histidine mutation have impaired growth and reduced virulence in mice, highlighting these proteins as potential targets for new treatments against toxoplasmosis.
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Affiliation(s)
- Mebratu A. Bitew
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, USA
| | - Pablo S. Gaete
- Department of Physiology and Membrane Biology, University of California, Davis, California, USA
| | - Christopher Swale
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences (IAB), INSERM U1209, CNRS UMR5309, University Grenoble Alpes, Grenoble, France
| | - Parag Maru
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, USA
| | - Jorge E. Contreras
- Department of Physiology and Membrane Biology, University of California, Davis, California, USA
| | - Jeroen P. J. Saeij
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, USA
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5
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Lüder CGK. IFNs in host defence and parasite immune evasion during Toxoplasma gondii infections. Front Immunol 2024; 15:1356216. [PMID: 38384452 PMCID: PMC10879624 DOI: 10.3389/fimmu.2024.1356216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 01/23/2024] [Indexed: 02/23/2024] Open
Abstract
Interferons (IFNs) are a family of cytokines with diverse functions in host resistance to pathogens and in immune regulation. Type II IFN, i.e. IFN-γ, is widely recognized as a major mediator of resistance to intracellular pathogens, including the protozoan Toxoplasma gondii. More recently, IFN-α/β, i.e. type I IFNs, and IFN-λ (type III IFN) have been identified to also play important roles during T. gondii infections. This parasite is a widespread pathogen of humans and animals, and it is a model organism to study cell-mediated immune responses to intracellular infection. Its success depends, among other factors, on the ability to counteract the IFN system, both at the level of IFN-mediated gene expression and at the level of IFN-regulated effector molecules. Here, I review recent advances in our understanding of the molecular mechanisms underlying IFN-mediated host resistance and immune regulation during T. gondii infections. I also discuss those mechanisms that T. gondii has evolved to efficiently evade IFN-mediated immunity. Knowledge of these fascinating host-parasite interactions and their underlying signalling machineries is crucial for a deeper understanding of the pathogenesis of toxoplasmosis, and it might also identify potential targets of parasite-directed or host-directed supportive therapies to combat the parasite more effectively.
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Affiliation(s)
- Carsten G. K. Lüder
- Institute for Medical Microbiology and Virology, University Medical Center Göttingen, Göttingen, Germany
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6
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Martin AT, Giri S, Safronova A, Eliseeva SI, Kwok SF, Yarovinsky F. Parasite-induced IFN-γ regulates host defense via CD115 and mTOR-dependent mechanism of tissue-resident macrophage death. PLoS Pathog 2024; 20:e1011502. [PMID: 38377133 PMCID: PMC10906828 DOI: 10.1371/journal.ppat.1011502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 03/01/2024] [Accepted: 01/22/2024] [Indexed: 02/22/2024] Open
Abstract
Host resistance to a common protozoan parasite Toxoplasma gondii relies on a coordinated immune response involving multiple cell types, including macrophages. Embryonically seeded tissue-resident macrophages (TRMs) play a critical role in maintaining tissue homeostasis, but their role in parasite clearance is poorly understood. In this study, we uncovered a crucial aspect of host defense against T. gondii mediated by TRMs. Through the use of neutralizing antibodies and conditional IFN-γ receptor-deficient mice, we demonstrated that IFN-γ directly mediated the elimination of TRMs. Mechanistically, IFN-γ stimulation in vivo rendered macrophages unresponsive to macrophage colony-stimulating factor (M-CSF) and inactivated mTOR signaling by causing the shedding of CD115 (CSFR1), the receptor for M-CSF. Further experiments revealed the essential role of macrophage IFN-γ responsiveness in host resistance to T. gondii. The elimination of peritoneal TRMs emerged as an additional host defense mechanism aimed at limiting the parasite's reservoir. The identified mechanism, involving IFN-γ-induced suppression of CD115-dependent mTOR signaling in macrophages, provides insights into the adaptation of macrophage subsets during infection and highlights a crucial aspect of host defense against intracellular pathogens.
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Affiliation(s)
- Andrew T. Martin
- Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Shilpi Giri
- Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Alexandra Safronova
- Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Sophia I. Eliseeva
- Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Samantha F. Kwok
- Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Felix Yarovinsky
- Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, United States of America
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7
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Zheng XN, Sun LX, Elsheikha HM, Li TT, Gao J, Wu XJ, Zhang ZW, Wang M, Fu BQ, Zhu XQ, Wang JL. A newly characterized dense granule protein (GRA76) is important for the growth and virulence of Toxoplasma gondii. Int J Parasitol 2024; 54:109-121. [PMID: 37832712 DOI: 10.1016/j.ijpara.2023.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/30/2023] [Accepted: 09/03/2023] [Indexed: 10/15/2023]
Abstract
Pathogenicity of the zoonotic pathogen Toxoplasma gondii largely depends on the secretion of effector proteins into the extracellular milieu and host cell cytosol, including the dense granule proteins (GRAs). The protein-encoding gene TGME49_299780 was previously identified as a contributor to parasite fitness. However, its involvement in parasite growth, virulence and infectivity in vitro and in vivo remains unknown. Here, we comprehensively examined the role of this new protein, termed GRA76, in parasite pathogenicity. Subcellular localization revealed high expression of GRA76 in tachyzoites inside the parasitophorous vacuole (PV). However, its expression was significantly decreased in bradyzoites. A CRISPR-Cas9 approach was used to knock out the gra76 gene in the T. gondii type I RH strain and type II Pru strain. The in vitro plaque assays and intracellular replication showed the involvement of GRA76 in replication of RH and Pru strains. Deletion of the gra76 gene significantly decreased parasite virulence, and reduced the brain cyst burden in mice. Using RNA sequencing, we detected a significant increase in the expression of bradyzoite-associated genes such as BAG1 and LDH2 in the PruΔgra76 strain compared with the wild-type Pru strain. Using an in vitro bradyzoite differentiation assay, we showed that loss of GRA76 significantly increased the propensity for parasites to form bradyzoites. Immunization with PruΔgra76 conferred partial protection against acute and chronic infection in mice. These findings show the important role of GRA76 in the pathogenesis of T. gondii and highlight the potential of PruΔgra76 as a candidate for a live-attenuated vaccine.
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Affiliation(s)
- Xiao-Nan Zheng
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Laboratory of Parasitic Diseases, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province 030801, People's Republic of China
| | - Li-Xiu Sun
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Research Center for Parasites & Vectors, College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan Province 410128, People's Republic of China
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Ting-Ting Li
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, Sichuan Province 610213, People's Republic of China
| | - Jin Gao
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Laboratory of Parasitic Diseases, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province 030801, People's Republic of China
| | - Xiao-Jing Wu
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Laboratory of Parasitic Diseases, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province 030801, People's Republic of China
| | - Zhi-Wei Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China
| | - Meng Wang
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, Sichuan Province 610213, People's Republic of China
| | - Bao-Quan Fu
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, Sichuan Province 610213, People's Republic of China
| | - Xing-Quan Zhu
- Laboratory of Parasitic Diseases, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province 030801, People's Republic of China.
| | - Jin-Lei Wang
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, People's Republic of China; Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, Sichuan Province 610213, People's Republic of China.
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8
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Li X, Chen Z, Ye W, Yu J, Zhang X, Li Y, Niu Y, Ran S, Wang S, Luo Z, Zhao J, Hao Y, Zong J, Xia C, Xia J, Wu J. High-throughput CRISPR technology: a novel horizon for solid organ transplantation. Front Immunol 2024; 14:1295523. [PMID: 38239344 PMCID: PMC10794540 DOI: 10.3389/fimmu.2023.1295523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 12/12/2023] [Indexed: 01/22/2024] Open
Abstract
Organ transplantation is the gold standard therapy for end-stage organ failure. However, the shortage of available grafts and long-term graft dysfunction remain the primary barriers to organ transplantation. Exploring approaches to solve these issues is urgent, and CRISPR/Cas9-based transcriptome editing provides one potential solution. Furthermore, combining CRISPR/Cas9-based gene editing with an ex vivo organ perfusion system would enable pre-implantation transcriptome editing of grafts. How to determine effective intervention targets becomes a new problem. Fortunately, the advent of high-throughput CRISPR screening has dramatically accelerated the effective targets. This review summarizes the current advancements, utilization, and workflow of CRISPR screening in various immune and non-immune cells. It also discusses the ongoing applications of CRISPR/Cas-based gene editing in transplantation and the prospective applications of CRISPR screening in solid organ transplantation.
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Affiliation(s)
- Xiaohan Li
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhang Chen
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Weicong Ye
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jizhang Yu
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xi Zhang
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuan Li
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuqing Niu
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shuan Ran
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Song Wang
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zilong Luo
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiulu Zhao
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yanglin Hao
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Junjie Zong
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chengkun Xia
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiahong Xia
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Organ Transplantation, Ministry of Education, National Health Commission (NHC) Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, China
| | - Jie Wu
- Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Center for Translational Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Organ Transplantation, Ministry of Education, National Health Commission (NHC) Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, China
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9
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Seizova S, Ferrel A, Boothroyd J, Tonkin CJ. Toxoplasma protein export and effector function. Nat Microbiol 2024; 9:17-28. [PMID: 38172621 DOI: 10.1038/s41564-023-01563-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 11/16/2023] [Indexed: 01/05/2024]
Abstract
Toxoplasma gondii is a single-celled eukaryotic parasite with a considerable host range that must invade the cells of warm-blooded hosts to survive and replicate. The challenges and opportunities that such a strategy represent have been met by the evolution of effectors that are delivered into host cells, counter host defences and co-opt host cell functions for their own purposes. These effectors are delivered in two waves using distinct machinery for each. In this Review, we focus on understanding the architecture of these protein-export systems and how their protein cargo is recognized and selected. We discuss the recent findings on the role that host manipulation has in latent Toxoplasma infections. We also discuss how these recent findings compare to protein export in the related Plasmodium spp. (the causative agent of malaria) and how this can inform our understanding of host manipulation in the larger Apicomplexa phylum and its evolution.
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Affiliation(s)
- Simona Seizova
- School of Life Sciences, The University of Dundee, Dundee, UK
| | - Abel Ferrel
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford University, Stanford, CA, USA
| | - John Boothroyd
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford University, Stanford, CA, USA.
| | - Christopher J Tonkin
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia.
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10
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Henry B, Sibley LD, Rosenberg A. A Combination of Four Nuclear Targeted Effectors Protects Toxoplasma Against Interferon Gamma Driven Human Host Cell Death During Acute Infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.24.573224. [PMID: 38234811 PMCID: PMC10793417 DOI: 10.1101/2023.12.24.573224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
In both mice and humans, Type II interferon-gamma (IFNγ) is crucial for regulation of Toxoplasma gondii (T. gondii) infection, during acute or chronic phases. To thwart this defense, T. gondii secretes protein effectors hindering the hosťs immune response. For example, T. gondii relies on the MYR translocon complex to deploy soluble dense granule effectors (GRAs) into the host cell cytosol or nucleus. Recent genome-wide loss-of-function screens in IFNγ-primed primary human fibroblasts identified MYR translocon components as crucial for parasite resistance against IFNγ driven vacuole clearance. However, these screens did not pinpoint specific MYR-dependent GRA proteins responsible for IFNγ signaling blockade, suggesting potential functional redundancy. Our study reveals that T. gondii depends on the MYR translocon complex to prevent host cell death and parasite premature egress in human cells stimulated with IFNγ postinfection, a unique phenotype observed in various human cell lines but not in murine cells. Intriguingly, inhibiting parasite egress did not prevent host cell death, indicating this mechanism is distinct from those described previously. Genome-wide loss-of-function screens uncovered TgIST, GRA16, GRA24, and GRA28 as effectors necessary for a complete block of IFNγ response. GRA24 and GRA28 directly influenced IFNγ driven transcription, GRA24's action depended on its interaction with p38 MAPK, while GRA28 disrupted histone acetyltransferase activity of CBP/p300. Given the intricate nature of the immune response to T. gondii, it appears that the parasite has evolved equally elaborate mechanisms to subvert IFNγ signaling, extending beyond direct interference with the JAK/STAT1 pathway, to encompass other signaling pathways as well.
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Affiliation(s)
- Brittany Henry
- Department of Infectious Diseases, Center for Tropical and Emerging Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - L. David Sibley
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Alex Rosenberg
- Department of Infectious Diseases, Center for Tropical and Emerging Infectious Diseases, University of Georgia, Athens, Georgia, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri, USA
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11
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May DA, Taha F, Child MA, Ewald SE. How colonization bottlenecks, tissue niches, and transmission strategies shape protozoan infections. Trends Parasitol 2023; 39:1074-1086. [PMID: 37839913 DOI: 10.1016/j.pt.2023.09.017] [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: 08/28/2023] [Revised: 09/25/2023] [Accepted: 09/25/2023] [Indexed: 10/17/2023]
Abstract
Protozoan pathogens such as Plasmodium spp., Leishmania spp., Toxoplasma gondii, and Trypanosoma spp. are often associated with high-mortality, acute and chronic diseases of global health concern. For transmission and immune evasion, protozoans have evolved diverse strategies to interact with a range of host tissue environments. These interactions are linked to disease pathology, yet our understanding of the association between parasite colonization and host homeostatic disruption is limited. Recently developed techniques for cellular barcoding have the potential to uncover the biology regulating parasite transmission, dissemination, and the stability of infection. Understanding bottlenecks to infection and the in vivo tissue niches that facilitate chronic infection and spread has the potential to reveal new aspects of parasite biology.
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Affiliation(s)
- Dana A May
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Fatima Taha
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Matthew A Child
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
| | - Sarah E Ewald
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
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12
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Bitew MA, Gaete PS, Swale C, Maru P, Contreras JE, Saeij JPJ. GRA47 and GRA72 are Toxoplasma gondii pore-forming proteins that influence small molecule permeability of the parasitophorous vacuole. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.15.567216. [PMID: 38014337 PMCID: PMC10680723 DOI: 10.1101/2023.11.15.567216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Toxoplasma gondii, a medically important intracellular parasite, uses GRA proteins, secreted from dense granule organelles, to mediate nutrient flux across the parasitophorous vacuole membrane (PVM). GRA17 and GRA23 are known pore-forming proteins on the PVM involved in this process, but the roles of additional proteins have remained largely uncharacterized. We recently identified GRA72 as synthetically lethal with GRA17. Deleting GRA72 produced similar phenotypes to Δgra17 parasites, and computational predictions suggested it forms a pore. To understand how GRA72 functions we performed immunoprecipitation experiments and identified GRA47 as an interactor of GRA72. Deletion of GRA47 resulted in an aberrant 'bubble vacuole' morphology with reduced small molecule permeability, mirroring the phenotype observed in GRA17 and GRA72 knockouts. Structural predictions indicated that GRA47 and GRA72 form heptameric and hexameric pores, respectively, with conserved histidine residues lining the pore. Mutational analysis highlighted the critical role of these histidines for protein functionality. Validation through electrophysiology confirmed alterations in membrane conductance, corroborating their pore-forming capabilities. Furthermore, Δgra47 parasites and parasites expressing GRA47 with a histidine mutation had reduced in vitro proliferation and attenuated virulence in mice. Our findings show the important roles of GRA47 and GRA72 in regulating PVM permeability, thereby expanding the repertoire of potential therapeutic targets against Toxoplasma infections.
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Affiliation(s)
- Mebratu A. Bitew
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis. Davis, California, USA
| | - Pablo S. Gaete
- Department of Physiology and Membrane Biology, University of California, Davis. Davis, California, USA
| | - Christopher Swale
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences (IAB), INSERM U1209, CNRS UMR5309, University Grenoble Alpes, Grenoble, France
| | - Parag Maru
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis. Davis, California, USA
| | - Jorge E. Contreras
- Department of Physiology and Membrane Biology, University of California, Davis. Davis, California, USA
| | - Jeroen P. J. Saeij
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis. Davis, California, USA
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13
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Ferrel A, Romano J, Panas MW, Coppens I, Boothroyd JC. Host MOSPD2 enrichment at the parasitophorous vacuole membrane varies between Toxoplasma strains and involves complex interactions. mSphere 2023; 8:e0067022. [PMID: 37341482 PMCID: PMC10449529 DOI: 10.1128/msphere.00670-22] [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: 12/22/2022] [Accepted: 04/25/2023] [Indexed: 06/22/2023] Open
Abstract
Toxoplasma gondii is an obligate, intracellular parasite. Infection of a cell produces a unique niche for the parasite named the parasitophorous vacuole (PV) initially composed of host plasma membrane invaginated during invasion. The PV and its membrane (parasitophorous vacuole membrane [PVM]) are subsequently decorated with a variety of parasite proteins allowing the parasite to optimally grow in addition to manipulate host processes. Recently, we reported a proximity-labeling screen at the PVM-host interface and identified host endoplasmic reticulum (ER)-resident motile sperm domain-containing protein 2 (MOSPD2) as being enriched at this location. Here we extend these findings in several important respects. First, we show that the extent and pattern of host MOSPD2 association with the PVM differ dramatically in cells infected with different strains of Toxoplasma. Second, in cells infected with Type I RH strain, the MOSPD2 staining is mutually exclusive with regions of the PVM that associate with mitochondria. Third, immunoprecipitation and liquid chromatography tandem mass spectrometry (LC-MS/MS) with epitope-tagged MOSPD2-expressing host cells reveal strong enrichment of several PVM-localized parasite proteins, although none appear to play an essential role in MOSPD2 association. Fourth, most MOSPD2 associating with the PVM is newly translated after infection of the cell and requires the major functional domains of MOSPD2, identified as the CRAL/TRIO domain and tail anchor, although these domains were not sufficient for PVM association. Lastly, ablation of MOSPD2 results in, at most, a modest impact on Toxoplasma growth in vitro. Collectively, these studies provide new insight into the molecular interactions involving MOSPD2 at the dynamic interface between the PVM and the host cytosol. IMPORTANCE Toxoplasma gondii is an intracellular pathogen that lives within a membranous vacuole inside of its host cell. This vacuole is decorated by a variety of parasite proteins that allow it to defend against host attack, acquire nutrients, and interact with the host cell. Recent work identified and validated host proteins enriched at this host-pathogen interface. Here, we follow up on one candidate named MOSPD2 shown to be enriched at the vacuolar membrane and describe it as having a dynamic interaction at this location depending on a variety of factors. Some of these include the presence of host mitochondria, intrinsic domains of the host protein, and whether translation is active. Importantly, we show that MOSPD2 enrichment at the vacuole membrane differs between strains indicating active involvement of the parasite with this phenotype. Altogether, these results shed light on the mechanism and role of protein associations in the host-pathogen interaction.
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Affiliation(s)
- Abel Ferrel
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
| | - Julia Romano
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Michael W. Panas
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - John C. Boothroyd
- Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, California, USA
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14
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Wang Y. mSphere of Influence: Systemic decoding gene function in Toxoplasma gondii pathogenesis-CRISPR screens and beyond. mSphere 2023; 8:e0027123. [PMID: 37382434 PMCID: PMC10449525 DOI: 10.1128/msphere.00271-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 05/16/2023] [Indexed: 06/30/2023] Open
Abstract
Yifan Wang works in the field of molecular parasitology with a focus on host-pathogen interactions. In this mSphere of Influence article, he reflects on how papers entitled "A genome-wide CRISPR screen in Toxoplasma identifies essential apicomplexan genes" by S. M. Sidik, D. Huet, S. M. Ganesan, M.-H. Huynh, et al. (Cell 166:1423.e12-1435.e12, 2016, https://doi.org/10.1016/j.cell.2016.08.019) and "Mapping host-microbe transcriptional interactions by dual Perturb-seq" by S. Butterworth, K. Kordova, S. Chandrasekaran, K. K. Thomas, et al. (bioRxiv, https://doi.org/10.1101/2023.04.21.537779) made an impact on his research and changed the way he thinks how functional genomics and high-throughput screens provide novel insights into pathogen pathogenesis.
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Affiliation(s)
- Yifan Wang
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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15
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Rico-San Román L, Amieva R, Horcajo P, García-Sánchez M, Pastor-Fernández I, Ortega-Mora LM, Collantes-Fernández E. Characterization of Neospora caninum virulence factors NcGRA7 and NcROP40 in bovine target cells. Vet Parasitol 2023; 320:109973. [PMID: 37356132 DOI: 10.1016/j.vetpar.2023.109973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/24/2023] [Accepted: 06/12/2023] [Indexed: 06/27/2023]
Abstract
Bovine neosporosis is one of the major causes of reproductive failure in cattle worldwide, and differences in virulence between isolates have been widely shown. However, the molecular basis and mechanisms underlying virulence in Neospora caninum are mostly unknown. Recently, we demonstrated the involvement of NcGRA7 and NcROP40 in the virulence of N. caninum in a pregnant murine model using single knockout mutants in these genes generated by CRISR/Cas9 technology. In this study, the role of these proteins was investigated in two in vitro models using bovine target cells: trophoblast (F3 cell line) and monocyte-derived macrophages (BoMØ). The proliferation capacity of the single knockout mutant parasites was compared to the wild-type strain, the Nc-Spain7 isolate, using both cell populations. For the bovine trophoblast, no differences were observed in the growth of the defective parasites compared to the wild-type strain, neither in the proliferation kinetics nor in the competition assay. However, in naïve BoMØ, a significant decrease in the proliferation capacity of the mutant parasites was observed from 48 h pi onwards. Stimulation of BoMØ with IFN-γ showed a similar inhibition of tachyzoite growth in defective and wild-type strains in a dose-dependent manner. Finally, BoMØ infected with knockout parasites showed higher expression levels of TLR3, which is involved in pathogen recognition. These results suggest that NcGRA7 and NcROP40 may be involved in the manipulation of innate immune defense mechanisms against neosporosis and confirm the usefulness of the BoMØ model for the evaluation of N. caninum virulence mechanisms. However, the specific functions of these proteins remain unknown, opening the way for future research.
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Affiliation(s)
- Laura Rico-San Román
- SALUVET, Animal Health Department, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Rafael Amieva
- SALUVET, Animal Health Department, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Pilar Horcajo
- SALUVET, Animal Health Department, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain.
| | - Marta García-Sánchez
- SALUVET-Innova S.L., Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Iván Pastor-Fernández
- SALUVET, Animal Health Department, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Luis Miguel Ortega-Mora
- SALUVET, Animal Health Department, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Esther Collantes-Fernández
- SALUVET, Animal Health Department, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
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16
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Hildebrandt F, Mohammed M, Dziedziech A, Bhandage AK, Divne AM, Barrenäs F, Barragan A, Henriksson J, Ankarklev J. scDual-Seq of Toxoplasma gondii-infected mouse BMDCs reveals heterogeneity and differential infection dynamics. Front Immunol 2023; 14:1224591. [PMID: 37575232 PMCID: PMC10415529 DOI: 10.3389/fimmu.2023.1224591] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 07/06/2023] [Indexed: 08/15/2023] Open
Abstract
Dendritic cells and macrophages are integral parts of the innate immune system and gatekeepers against infection. The protozoan pathogen, Toxoplasma gondii, is known to hijack host immune cells and modulate their immune response, making it a compelling model to study host-pathogen interactions. Here we utilize single cell Dual RNA-seq to parse out heterogeneous transcription of mouse bone marrow-derived dendritic cells (BMDCs) infected with two distinct genotypes of T. gondii parasites, over multiple time points post infection. We show that the BMDCs elicit differential responses towards T. gondii infection and that the two parasite lineages distinctly manipulate subpopulations of infected BMDCs. Co-expression networks define host and parasite genes, with implications for modulation of host immunity. Integrative analysis validates previously established immune pathways and additionally, suggests novel candidate genes involved in host-pathogen interactions. Altogether, this study provides a comprehensive resource for characterizing host-pathogen interplay at high-resolution.
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Affiliation(s)
- Franziska Hildebrandt
- Department of Molecular Biosciences, The Wenner Gren Institute, Stockholm University, Stockholm, Sweden
| | - Mubasher Mohammed
- Department of Molecular Biosciences, The Wenner Gren Institute, Stockholm University, Stockholm, Sweden
| | - Alexis Dziedziech
- Department of Molecular Biosciences, The Wenner Gren Institute, Stockholm University, Stockholm, Sweden
- Department of Global Health, Institut Pasteur, Paris, France
| | - Amol K. Bhandage
- Department of Molecular Biosciences, The Wenner Gren Institute, Stockholm University, Stockholm, Sweden
| | - Anna-Maria Divne
- Microbial Single Cell Genomics Facility, SciLifeLab, Biomedical Center (BMC) Uppsala University, Uppsala, Sweden
| | - Fredrik Barrenäs
- Department of Molecular Biosciences, The Wenner Gren Institute, Stockholm University, Stockholm, Sweden
| | - Antonio Barragan
- Department of Molecular Biosciences, The Wenner Gren Institute, Stockholm University, Stockholm, Sweden
| | - Johan Henriksson
- Laboratory of Molecular Infection Medicine Sweden (MIMS), Umeå Center for Microbial Research, Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Johan Ankarklev
- Department of Molecular Biosciences, The Wenner Gren Institute, Stockholm University, Stockholm, Sweden
- Microbial Single Cell Genomics Facility, SciLifeLab, Biomedical Center (BMC) Uppsala University, Uppsala, Sweden
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17
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Paredes-Santos TC, Bitew MA, Swale C, Rodriguez F, Krishnamurthy S, Wang Y, Maru P, Sangaré LO, Saeij JPJ. Genome-wide CRISPR screen identifies genes synthetically lethal with GRA17, a nutrient channel encoding gene in Toxoplasma. PLoS Pathog 2023; 19:e1011543. [PMID: 37498952 PMCID: PMC10409377 DOI: 10.1371/journal.ppat.1011543] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 08/08/2023] [Accepted: 07/06/2023] [Indexed: 07/29/2023] Open
Abstract
Toxoplasma gondii is a parasite that replicates within a specialized compartment called the parasitophorous vacuole (PV), which is surrounded by the PV membrane (PVM). To obtain essential nutrients, Toxoplasma must transport molecules across the PVM, a process mediated by the secreted parasite proteins GRA17 and GRA23. These proteins form pores in the PVM through which small molecules can diffuse in and out of the PV. GRA17 and GRA23 are synthetically lethal, suggesting that at least one pore type is essential for parasite survival. In the 'nutrient sensitized' Δgra17 strain it is likely that other Toxoplasma genes become essential, because they mediate nutrient acquisition from the host or are involved in the trafficking of GRA23 to the PVM. To identify these genes, a genome-wide loss-of-function screen was performed in wild-type and Δgra17 parasites, which identified multiple genes that were synthetically sick/lethal with GRA17. Several of these genes were involved in the correct localization of GRAs, including GRA17/GRA23, to the PVM. One of the top hits, GRA72, was predicted to form a pore on the PVM, and its deletion led to the formation of enlarged "bubble vacuoles" with reduced PVM small molecule permeability, similar to what was previously observed for Δgra17 parasites. Furthermore, Δgra72 parasites had reduced in vitro growth and virulence in mice. These findings suggest that in the absence of GRA17, other genes become essential, likely because they play a role in the proper localization of GRA23 (and other GRAs) or because they determine host-derived nutrient acquisition at the PVM.
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Affiliation(s)
- Tatiana C. Paredes-Santos
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Mebratu A. Bitew
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Christopher Swale
- Team Host-Pathogen Interactions and Immunity to Infection, Institute for Advanced Biosciences (IAB), INSERM U1209, CNRS UMR5309, University Grenoble Alpes, Grenoble, France
| | - Felipe Rodriguez
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Shruthi Krishnamurthy
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Yifan Wang
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Parag Maru
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Lamba Omar Sangaré
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Jeroen P. J. Saeij
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
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18
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Tachibana Y, Hashizaki E, Sasai M, Yamamoto M. Host genetics highlights IFN-γ-dependent Toxoplasma genes encoding secreted and non-secreted virulence factors in in vivo CRISPR screens. Cell Rep 2023; 42:112592. [PMID: 37269286 DOI: 10.1016/j.celrep.2023.112592] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/25/2023] [Accepted: 05/17/2023] [Indexed: 06/05/2023] Open
Abstract
Secreted virulence factors of Toxoplasma to survive in immune-competent hosts have been extensively explored by classical genetics and in vivo CRISPR screen methods, whereas their requirements in immune-deficient hosts are incompletely understood. Those of non-secreted virulence factors are further enigmatic. Here we develop an in vivo CRISPR screen system to enrich not only secreted but also non-secreted virulence factors in virulent Toxoplasma-infected C57BL/6 mice. Notably, combined usage of immune-deficient Ifngr1-/- mice highlights genes encoding various non-secreted proteins as well as well-known effectors such as ROP5, ROP18, GRA12, and GRA45 as interferon-γ (IFN-γ)-dependent virulence genes. The screen results suggest a role of GRA72 for normal GRA17/GRA23 localization and the IFN-γ-dependent role of UFMylation-related genes. Collectively, our study demonstrates that host genetics can complement in vivo CRISPR screens to highlight genes encoding IFN-γ-dependent secreted and non-secreted virulence factors in Toxoplasma.
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Affiliation(s)
- Yuta Tachibana
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan; Laboratory of Immunoparasitology, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Emi Hashizaki
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan; Laboratory of Immunoparasitology, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Miwa Sasai
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan; Laboratory of Immunoparasitology, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan; Department of Immunoparasitology, Center for Infectious Disease Education and Research, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masahiro Yamamoto
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan; Laboratory of Immunoparasitology, WPI Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan; Department of Immunoparasitology, Center for Infectious Disease Education and Research, Osaka University, Suita, Osaka 565-0871, Japan.
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19
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Aghabi D, Sloan M, Gill G, Hartmann E, Antipova O, Dou Z, Guerra AJ, Carruthers VB, Harding CR. The vacuolar iron transporter mediates iron detoxification in Toxoplasma gondii. Nat Commun 2023; 14:3659. [PMID: 37339985 PMCID: PMC10281983 DOI: 10.1038/s41467-023-39436-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 06/13/2023] [Indexed: 06/22/2023] Open
Abstract
Iron is essential to cells as a cofactor in enzymes of respiration and replication, however without correct storage, iron leads to the formation of dangerous oxygen radicals. In yeast and plants, iron is transported into a membrane-bound vacuole by the vacuolar iron transporter (VIT). This transporter is conserved in the apicomplexan family of obligate intracellular parasites, including in Toxoplasma gondii. Here, we assess the role of VIT and iron storage in T. gondii. By deleting VIT, we find a slight growth defect in vitro, and iron hypersensitivity, confirming its essential role in parasite iron detoxification, which can be rescued by scavenging of oxygen radicals. We show VIT expression is regulated by iron at transcript and protein levels, and by altering VIT localization. In the absence of VIT, T. gondii responds by altering expression of iron metabolism genes and by increasing antioxidant protein catalase activity. We also show that iron detoxification has an important role both in parasite survival within macrophages and in virulence in a mouse model. Together, by demonstrating a critical role for VIT during iron detoxification in T. gondii, we reveal the importance of iron storage in the parasite and provide the first insight into the machinery involved.
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Affiliation(s)
- Dana Aghabi
- Wellcome Centre of Integrative Parasitology, School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Megan Sloan
- Wellcome Centre of Integrative Parasitology, School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Grace Gill
- Wellcome Centre of Integrative Parasitology, School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Elena Hartmann
- Wellcome Centre of Integrative Parasitology, School of Infection and Immunity, University of Glasgow, Glasgow, UK
| | - Olga Antipova
- X-Ray Sciences Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL, USA
| | - Zhicheng Dou
- Department of Biological Sciences, Clemson University, Clemson, SC, USA
| | - Alfredo J Guerra
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
- Cayman Chemical Company, Ann Arbor, MI, USA
| | - Vern B Carruthers
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Clare R Harding
- Wellcome Centre of Integrative Parasitology, School of Infection and Immunity, University of Glasgow, Glasgow, UK.
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20
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CRISPR Screens Identify Toxoplasma Genes That Determine Parasite Fitness in Interferon Gamma-Stimulated Human Cells. mBio 2023; 14:e0006023. [PMID: 36916910 PMCID: PMC10128063 DOI: 10.1128/mbio.00060-23] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Toxoplasma virulence depends on its ability to evade or survive the toxoplasmacidal mechanisms induced by interferon gamma (IFNγ). While many Toxoplasma genes involved in the evasion of the murine IFNγ response have been identified, genes required to survive the human IFNγ response are largely unknown. In this study, we used a genome-wide loss-of-function screen to identify Toxoplasma genes important for parasite fitness in IFNγ-stimulated primary human fibroblasts. We generated gene knockouts for the top six hits from the screen and confirmed their importance for parasite growth in IFNγ-stimulated human fibroblasts. Of these six genes, three have homology to GRA32, localize to dense granules, and coimmunoprecipitate with each other and GRA32, suggesting they might form a complex. Deletion of individual members of this complex leads to early parasite egress in IFNγ-stimulated cells. Thus, prevention of early egress is an important Toxoplasma fitness determinant in IFNγ-stimulated human cells. IMPORTANCE Toxoplasma infection causes serious complications in immunocompromised individuals and in the developing fetus. During infection, certain immune cells release a protein called interferon gamma that activates cells to destroy the parasite or inhibit its growth. While most Toxoplasma parasites are cleared by this immune response, some can survive by blocking or evading the IFNγ-induced restrictive environment. Many Toxoplasma genes that determine parasite survival in IFNγ-activated murine cells are known but parasite genes conferring fitness in IFNγ-activated human cells are largely unknown. Using a Toxoplasma adapted genome-wide loss-of-function screen, we identified many Toxoplasma genes that determine parasite fitness in IFNγ-activated human cells. The gene products of four top hits play a role in preventing early parasite egress in IFNγ-stimulated human cells. Understanding how IFNγ-stimulated human cells inhibit Toxoplasma growth and how Toxoplasma counteracts this, could lead to the development of novel therapeutics.
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21
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Giuliano CJ, Wei KJ, Harling FM, Waldman BS, Farringer MA, Boydston EA, Lan TCT, Thomas RW, Herneisen AL, Sanderlin AG, Coppens I, Dvorin JD, Lourido S. Functional profiling of the Toxoplasma genome during acute mouse infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.05.531216. [PMID: 36945434 PMCID: PMC10028831 DOI: 10.1101/2023.03.05.531216] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Within a host, pathogens encounter a diverse and changing landscape of cell types, nutrients, and immune responses. Examining host-pathogen interactions in animal models can therefore reveal aspects of infection absent from cell culture. We use CRISPR-based screens to functionally profile the entire genome of the model apicomplexan parasite Toxoplasma gondii during mouse infection. Barcoded gRNAs were used to track mutant parasite lineages, enabling detection of bottlenecks and mapping of population structures. We uncovered over 300 genes that modulate parasite fitness in mice with previously unknown roles in infection. These candidates span multiple axes of host-parasite interaction, including determinants of tropism, host organelle remodeling, and metabolic rewiring. We mechanistically characterized three novel candidates, including GTP cyclohydrolase I, against which a small-molecule inhibitor could be repurposed as an antiparasitic compound. This compound exhibited antiparasitic activity against T. gondii and Plasmodium falciparum, the most lethal agent of malaria. Taken together, we present the first complete survey of an apicomplexan genome during infection of an animal host, and point to novel interfaces of host-parasite interaction that may offer new avenues for treatment.
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Affiliation(s)
| | - Kenneth J. Wei
- Whitehead Institute, Cambridge, MA
- Biology Department, MIT, Cambridge, MA
| | - Faye M. Harling
- Whitehead Institute, Cambridge, MA
- Biology Department, MIT, Cambridge, MA
| | | | - Madeline A. Farringer
- Division of Infectious Diseases, Boston Children’s Hospital, Boston, Massachusetts, USA
- Biological Sciences in Public Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | | | | | - Raina W. Thomas
- Whitehead Institute, Cambridge, MA
- Biology Department, MIT, Cambridge, MA
| | - Alice L. Herneisen
- Whitehead Institute, Cambridge, MA
- Biology Department, MIT, Cambridge, MA
| | | | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Jeffrey D. Dvorin
- Division of Infectious Diseases, Boston Children’s Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Sebastian Lourido
- Whitehead Institute, Cambridge, MA
- Biology Department, MIT, Cambridge, MA
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22
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Toxoplasma IWS1 Determines Fitness in Interferon-γ-Activated Host Cells and Mice by Indirectly Regulating ROP18 mRNA Expression. mBio 2023; 14:e0325622. [PMID: 36715543 PMCID: PMC9973038 DOI: 10.1128/mbio.03256-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Toxoplasma gondii secretes various virulence effector molecules into host cells to disrupt host interferon-γ (IFN-γ)-dependent immunity. Among these effectors, ROP18 directly phosphorylates and inactivates IFN-inducible GTPases, such as immunity-related GTPases (IRGs) and guanylate-binding proteins (GBPs), leading to the subversion of IFN-inducible GTPase-induced cell-autonomous immunity. The modes of action of ROP18 have been studied extensively; however, little is known about the molecular mechanisms by which ROP18 is produced in the parasite itself. Here, we report the role of T. gondii transcription factor IWS1 in ROP18 mRNA expression in the parasite. Compared with wild-type virulent type I T. gondii, IWS1-deficient parasites showed dramatically increased loading of IRGs and GBPs onto the parasitophorous vacuole membrane (PVM). Moreover, IWS1-deficient parasites displayed decreased virulence in wild-type mice but retained normal virulence in mice lacking the IFN-γ receptor. Furthermore, IWS1-deficient parasites showed severely decreased ROP18 mRNA expression; however, tagged IWS1 did not directly bind with genomic regions of the ROP18 locus. Ectopic expression of ROP18 in IWS1-deficient parasites restored the decreased loading of effectors onto the PVM and in vivo virulence in wild-type mice. Taken together, these data demonstrate that T. gondii IWS1 indirectly regulates ROP18 mRNA expression to determine fitness in IFN-γ-activated host cells and mice. IMPORTANCE The parasite Toxoplasma gondii has a counterdefense system against interferon-γ (IFN-γ)-dependent host immunity which relies on the secretion of parasite effector proteins. ROP18 is one of the effector, which is released into host cells to inactivate IFN-γ-dependent anti-Toxoplasma host proteins. The mechanism by which Toxoplasma ROP18 subverts host immunity has been extensively analyzed, but how Toxoplasma produces this virulence factor remains unclear. Here, we show that Toxoplasma transcription factor IWS1 is important for ROP18 mRNA expression in the parasite. Loss of IWS1 from virulent Toxoplasma leads to dramatically decreased ROP18 mRNA expression, resulting in profoundly decreased virulence due to greater activity of IFN-γ-dependent host immune responses. Thus, Toxoplasma prepares the critical virulence factor ROP18 via an IWS1-dependent system to negate IFN-γ-dependent antiparasitic immunity and thus survive in the host.
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23
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Functional Characterization of 15 Novel Dense Granule Proteins in Toxoplasma gondii Using the CRISPR-Cas9 System. Microbiol Spectr 2023; 11:e0307822. [PMID: 36515555 PMCID: PMC9927372 DOI: 10.1128/spectrum.03078-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The analysis of the subcellular localization and function of dense granule proteins (GRAs) is of central importance for the understanding of host-parasite interaction and pathogenesis of Toxoplasma gondii infection. Here, we identified 15 novel GRAs and used C-terminal endogenous gene tagging to determine their localization at the intravacuolar network (IVN), parasitophorous vacuole (PV), or PV membrane (PVM) in the tachyzoites and at the periphery of the bradyzoites-containing cysts. The functions of the 15 gra genes were examined in type I RH strain and 5 of these gra genes were also evaluated in the cyst-forming type II Pru strain. The 15 novel gra genes were successfully disrupted by using CRISPR-Cas9 mediated homologous recombination and the results showed that 13 gra genes were not individually essential for T. gondii replication in vitro or virulence in mice during acute and chronic infection. Intriguingly, deletion of TGME49_266410 and TGME49_315910 in both RH and Pru strains decreased the parasite replication in vitro and attenuated its virulence, and also reduced the cyst-forming ability of the Pru strain in mice during chronic infection. Comparison of the transcriptomic profiles of the 15 gra genes suggests that they may play roles in other life cycle stages and genotypes of T. gondii. Taken together, our findings improve the understanding of T. gondii pathogenesis and demonstrate the involvement of two novel GRAs, TGME49_266410 and TGME49_315910, in the parasite replication and virulence. IMPORTANCE Dense granule proteins (GRAs) play important roles in Toxoplasma gondii pathogenicity. However, the functions of many putative GRAs have not been elucidated. Here, we found that 15 novel GRAs are secreted into intravacuolar network (IVN), parasitophorous vacuole (PV), or PV membrane (PVM) in tachyzoites and are located at the periphery of the bradyzoite-containing cysts. TGME49_266410 and TGME49_315910 were crucial to the growth of RH and Pru strains in vitro. Deletion of TGME49_266410 and TGME49_315910 attenuated the parasite virulence in mice. However, disruption of other 13 gra genes did not have a significant impact on the proliferation and pathogenicity of T. gondii in vitro or in vivo. The marked effects of the two novel GRAs (TGME49_266410 and TGME49_315910) on the in vitro growth and virulence of T. gondii are notable and warrant further elucidation of the temporal and spatial dynamics of translocation of these two novel GRAs and how do they interfere with host cell functions.
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24
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Toxoplasma Shelph, a Phosphatase Located in the Parasite Endoplasmic Reticulum, Is Required for Parasite Virulence. mSphere 2022; 7:e0035022. [PMID: 36326242 PMCID: PMC9769683 DOI: 10.1128/msphere.00350-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Toxoplasma gondii is a single-celled parasitic eukaryote that evolved to successfully propagate in any nucleated cell. As with any other eukaryote, its life cycle is regulated by signaling pathways controlled by kinases and phosphatases. T. gondii encodes an atypical bacterial-like phosphatase absent from mammalian genomes, named Shelph, after its first identification in the psychrophilic bacterium Schewanella sp. Here, we demonstrate that Toxoplasma Shelph is an active phosphatase localized in the parasite endoplasmic reticulum. The phenotyping of a shelph knockout (KO) line showed a minor impairment in invasion on human fibroblasts, while the other steps of the parasite lytic cycle were not affected. In contrast with Plasmodium ortholog Shelph1, this invasion deficiency was not correlated with any default in the biogenesis of secretory organelles. However, Shelph-KO parasites displayed a much-pronounced defect in virulence in vivo. These phenotypes could be rescued by genetic complementation, thus supporting an important function for Shelph in the context of a natural infection. IMPORTANCE Toxoplasma gondii belongs to the Apicomplexa phylum, which comprises more than 5,000 species, among which is Plasmodium falciparum, the notorious agent of human malaria. Intriguingly, the Apicomplexa genomes encode at least one phosphatase closely related to the bacterial Schewanella phosphatase, or Shelph. To better understand the importance of these atypical bacterial enzymes in eukaryotic parasites, we undertook the functional characterization of T. gondii Shelph. Our results uncovered its subcellular localization and its enzymatic activity, revealed its subtle involvement during the tachyzoite invasion step of the lytic cycle, and more importantly, highlighted a critical requirement of this phosphatase for parasite propagation in mice. Overall, this study revealed an unexpected role for T. gondii Shelph in the maintenance of parasite virulence in vivo.
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25
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Butterworth S, Torelli F, Lockyer EJ, Wagener J, Song OR, Broncel M, Russell MRG, Moreira-Souza ACA, Young JC, Treeck M. Toxoplasma gondii virulence factor ROP1 reduces parasite susceptibility to murine and human innate immune restriction. PLoS Pathog 2022; 18:e1011021. [PMID: 36476844 PMCID: PMC9762571 DOI: 10.1371/journal.ppat.1011021] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 12/19/2022] [Accepted: 11/24/2022] [Indexed: 12/12/2022] Open
Abstract
Toxoplasma gondii is an intracellular parasite that can infect many host species and is a cause of significant human morbidity worldwide. T. gondii secretes a diverse array of effector proteins into the host cell which are critical for infection. The vast majority of these secreted proteins have no predicted functional domains and remain uncharacterised. Here, we carried out a pooled CRISPR knockout screen in the T. gondii Prugniaud strain in vivo to identify secreted proteins that contribute to parasite immune evasion in the host. We demonstrate that ROP1, the first-identified rhoptry protein of T. gondii, is essential for virulence and has a previously unrecognised role in parasite resistance to interferon gamma-mediated innate immune restriction. This function is conserved in the highly virulent RH strain of T. gondii and contributes to parasite growth in both murine and human macrophages. While ROP1 affects the morphology of rhoptries, from where the protein is secreted, it does not affect rhoptry secretion. Finally, we show that ROP1 co-immunoprecipitates with the host cell protein C1QBP, an emerging regulator of innate immune signaling. In summary, we identify putative in vivo virulence factors in the T. gondii Prugniaud strain and show that ROP1 is an important and previously overlooked effector protein that counteracts both murine and human innate immunity.
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Affiliation(s)
- Simon Butterworth
- Signalling In Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Francesca Torelli
- Signalling In Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Eloise J. Lockyer
- Signalling In Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Jeanette Wagener
- Signalling In Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Ok-Ryul Song
- High-Throughput Screening Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Malgorzata Broncel
- Signalling In Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
- Proteomics Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | - Matt R. G. Russell
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, London, United Kingdom
| | | | - Joanna C. Young
- Signalling In Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Moritz Treeck
- Signalling In Apicomplexan Parasites Laboratory, The Francis Crick Institute, London, United Kingdom
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26
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Ten Hoeve AL, Braun L, Rodriguez ME, Olivera GC, Bougdour A, Belmudes L, Couté Y, Saeij JPJ, Hakimi MA, Barragan A. The Toxoplasma effector GRA28 promotes parasite dissemination by inducing dendritic cell-like migratory properties in infected macrophages. Cell Host Microbe 2022; 30:1570-1588.e7. [PMID: 36309013 PMCID: PMC9710525 DOI: 10.1016/j.chom.2022.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 08/26/2022] [Accepted: 10/03/2022] [Indexed: 11/03/2022]
Abstract
Upon pathogen detection, macrophages normally stay sessile in tissues while dendritic cells (DCs) migrate to secondary lymphoid tissues. The obligate intracellular protozoan Toxoplasma gondii exploits the trafficking of mononuclear phagocytes for dissemination via unclear mechanisms. We report that, upon T. gondii infection, macrophages initiate the expression of transcription factors normally attributed to DCs, upregulate CCR7 expression with a chemotactic response, and perform systemic migration when adoptively transferred into mice. We show that parasite effector GRA28, released by the MYR1 secretory pathway, cooperates with host chromatin remodelers in the host cell nucleus to drive the chemotactic migration of parasitized macrophages. During in vivo challenge studies, bone marrow-derived macrophages infected with wild-type T. gondii outcompeted those challenged with MYR1- or GRA28-deficient strains in migrating and reaching secondary organs. This work reveals how an intracellular parasite hijacks chemotaxis in phagocytes and highlights a remarkable migratory plasticity in differentiated cells of the mononuclear phagocyte system.
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Affiliation(s)
- Arne L Ten Hoeve
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Laurence Braun
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Matias E Rodriguez
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Gabriela C Olivera
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Alexandre Bougdour
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France
| | - Lucid Belmudes
- Univ. Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Yohann Couté
- Univ. Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Jeroen P J Saeij
- Department of Pathology, Microbiology, and Immunology, University of California Davis, Davis, CA 95616, USA
| | - Mohamed-Ali Hakimi
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, Grenoble, France.
| | - Antonio Barragan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden.
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27
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Griffith MB, Pearce CS, Heaslip AT. Dense granule biogenesis, secretion, and function in Toxoplasma gondii. J Eukaryot Microbiol 2022; 69:e12904. [PMID: 35302693 PMCID: PMC9482668 DOI: 10.1111/jeu.12904] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Toxoplasma gondii is an obligate intracellular parasite and the causative agent of Toxoplasmosis. A key to understanding and treating the disease lies with determining how the parasite can survive and replicate within cells of its host. Proteins released from specialized secretory vesicles, named the dense granules (DGs), have diverse functions that are critical for adapting the intracellular environment, and are thus key to survival and pathogenicity. In this review, we describe the current understanding and outstanding questions regarding dense granule biogenesis, trafficking, and regulation of secretion. In addition, we provide an overview of dense granule protein ("GRA") function upon secretion, with a focus on proteins that have recently been identified.
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Affiliation(s)
- Michael B Griffith
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Camille S Pearce
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Aoife T Heaslip
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
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28
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Guimarães Gois PS, Franco PS, Cota Teixeira S, Guirelli PM, de Araújo TE, da Fonseca Batistão DW, de Oliveira FC, Lícia Santos Ferreira G, de Oliveira Gomes A, Favoreto S, Mineo JR, de Freitas Barbosa B, Ferro EAV. Polarisation of human macrophages towards an M1 subtype triggered by an atypical Brazilian strain of Toxoplasma gondii results in a reduction in parasite burden. Folia Parasitol (Praha) 2022; 69. [DOI: 10.14411/fp.2022.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 06/16/2022] [Indexed: 11/19/2022]
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29
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Tsee Dawson A, Tonkin CJ. A CRISPR upgrade unlocks Toxoplasma gene function. Trends Parasitol 2022; 38:826-828. [PMID: 35973902 DOI: 10.1016/j.pt.2022.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 07/22/2022] [Indexed: 10/15/2022]
Abstract
Forward genetic screens are invaluable in describing gene function. CRISPR has reinvigorated phenotypic screens in Toxoplasma - a model apicomplexan parasite. Two recent papers by Smith et al. and Li et al. take the next big leap in performing forward genetic screens in Toxoplasma by combining conditional gene regulation with CRISPR.
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Affiliation(s)
- Aurelie Tsee Dawson
- The Division of Infectious Diseases and Immune Defense, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, Victoria, Australia
| | - Christopher J Tonkin
- The Division of Infectious Diseases and Immune Defense, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne, Victoria, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Melbourne, Victoria, Australia.
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30
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Kent RS, Briggs EM, Colon BL, Alvarez C, Silva Pereira S, De Niz M. Paving the Way: Contributions of Big Data to Apicomplexan and Kinetoplastid Research. Front Cell Infect Microbiol 2022; 12:900878. [PMID: 35734575 PMCID: PMC9207352 DOI: 10.3389/fcimb.2022.900878] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/06/2022] [Indexed: 11/13/2022] Open
Abstract
In the age of big data an important question is how to ensure we make the most out of the resources we generate. In this review, we discuss the major methods used in Apicomplexan and Kinetoplastid research to produce big datasets and advance our understanding of Plasmodium, Toxoplasma, Cryptosporidium, Trypanosoma and Leishmania biology. We debate the benefits and limitations of the current technologies, and propose future advancements that may be key to improving our use of these techniques. Finally, we consider the difficulties the field faces when trying to make the most of the abundance of data that has already been, and will continue to be, generated.
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Affiliation(s)
- Robyn S. Kent
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, United States
| | - Emma M. Briggs
- Institute for Immunology and Infection Research, School of Biological Sciences, University Edinburgh, Edinburgh, United Kingdom
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Beatrice L. Colon
- Wellcome Centre for Anti-Infectives Research, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Catalina Alvarez
- de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Sara Silva Pereira
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal
| | - Mariana De Niz
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Lisboa, Portugal
- Institut Pasteur, Paris, France
- *Correspondence: Mariana De Niz,
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31
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CRISPR/Cas9 and genetic screens in malaria parasites: small genomes, big impact. Biochem Soc Trans 2022; 50:1069-1079. [PMID: 35621119 PMCID: PMC9246331 DOI: 10.1042/bst20210281] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/20/2022] [Accepted: 04/29/2022] [Indexed: 12/19/2022]
Abstract
The ∼30 Mb genomes of the Plasmodium parasites that cause malaria each encode ∼5000 genes, but the functions of the majority remain unknown. This is due to a paucity of functional annotation from sequence homology, which is compounded by low genetic tractability compared with many model organisms. In recent years technical breakthroughs have made forward and reverse genome-scale screens in Plasmodium possible. Furthermore, the adaptation of Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-Associated protein 9 (CRISPR/Cas9) technology has dramatically improved gene editing efficiency at the single gene level. Here, we review the arrival of genetic screens in malaria parasites to analyse parasite gene function at a genome-scale and their impact on understanding parasite biology. CRISPR/Cas9 screens, which have revolutionised human and model organism research, have not yet been implemented in malaria parasites due to the need for more complex CRISPR/Cas9 gene targeting vector libraries. We therefore introduce the reader to CRISPR-based screens in the related apicomplexan Toxoplasma gondii and discuss how these approaches could be adapted to develop CRISPR/Cas9 based genome-scale genetic screens in malaria parasites. Moreover, since more than half of Plasmodium genes are required for normal asexual blood-stage reproduction, and cannot be targeted using knockout methods, we discuss how CRISPR/Cas9 could be used to scale up conditional gene knockdown approaches to systematically assign function to essential genes.
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32
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Host cell proteins modulated upon Toxoplasma infection identified using proteomic approaches: a molecular rationale. Parasitol Res 2022; 121:1853-1865. [PMID: 35552534 DOI: 10.1007/s00436-022-07541-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 04/12/2022] [Indexed: 10/18/2022]
Abstract
Toxoplasma gondii is a pathogenic protozoan parasite belonging to the apicomplexan phylum that infects the nucleated cells of warm-blooded hosts leading to an infectious disease known as toxoplasmosis. Apicomplexan parasites such as T. gondii can display different mechanisms to control or manipulate host cells signaling at different levels altering the host subcellular genome and proteome. Indeed, Toxoplasma is able to modulate host cell responses (especially immune responses) during infection to its advantage through both structural and functional changes in the proteome of different infected cells. Consequently, parasites can transform the invaded cells into a suitable environment for its own replication and the induction of infection. Proteomics as an applicable tool can identify such critical proteins involved in pathogen (Toxoplasma)-host cell interactions and consequently clarify the cellular mechanisms that facilitate the entry of pathogens into host cells, and their replication and transmission, as well as the central mechanisms of host defense against pathogens. Accordingly, the current paper reviews several proteins (identified using proteomic approaches) differentially expressed in the proteome of Toxoplasma-infected host cells (macrophages and human foreskin fibroblasts) and tissues (brain and liver) and highlights their plausible functions in the cellular biology of the infected cells. The identification of such modulated proteins and their related cell impact (cell responses/signaling) can provide further information regarding parasite pathogenesis and biology that might lead to a better understanding of therapeutic strategies and novel drug targets.
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Abstract
Toxoplasma gondii is a parasitic protist infecting a wide group of warm-blooded animals, ranging from birds to humans. While this infection is usually asymptomatic in healthy individuals, it can also lead to severe ocular or neurological outcomes in immunocompromised individuals or in developing fetuses. This obligate intracellular parasite has the ability to infect a considerable range of nucleated cells and can propagate in the intermediate host. Yet, under the pressure of the immune system it transforms into an encysted persistent form residing primarily in the brain and muscle tissues. Encysted parasites, which are resistant to current medication, may reactivate and give rise to an acute infection. The clinical outcome of toxoplasmosis depends on a complex balance between the host immune response and parasite virulence factors. Susceptibility to the disease is thus determined by both parasite strains and host species. Recent advances on our understanding of host cell-parasite interactions and parasite virulence have brought new insights into the pathophysiology of T. gondii infection and are summarized here.
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34
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Proximity-Labeling Reveals Novel Host and Parasite Proteins at the Toxoplasma Parasitophorous Vacuole Membrane. mBio 2021; 12:e0026021. [PMID: 34749525 PMCID: PMC8576527 DOI: 10.1128/mbio.00260-21] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Toxoplasma gondii is a ubiquitous, intracellular parasite that envelops its parasitophorous vacuole with a protein-laden membrane (PVM). The PVM is critical for interactions with the infected host cell, such as nutrient transport and immune defense. Only a few parasite and host proteins have so far been identified on the host-cytosolic side of the Toxoplasma PVM. We report here the use of human foreskin fibroblasts expressing the proximity-labeling enzyme miniTurbo, fused to a domain that targets it to this face of the PVM, in combination with quantitative proteomics to specifically identify proteins present at this interface. Out of numerous human and parasite proteins with candidate PVM localization, we validate three parasite proteins (TGGT1_269950 [GRA61], TGGT1_215360 [GRA62], and TGGT1_217530 [GRA63]) and four new host proteins (PDCD6IP/ALIX, PDCD6, CC2D1A, and MOSPD2) as localized to the PVM in infected human cells through immunofluorescence microscopy. These results significantly expand our knowledge of proteins present at the Toxoplasma PVM and, given that three of the validated host proteins are components of the ESCRT (endosomal sorting complexes required for transport) machinery, they further suggest that novel biology is operating at this crucial host-pathogen interface.
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Frickel EM, Hunter CA. Lessons from Toxoplasma: Host responses that mediate parasite control and the microbial effectors that subvert them. J Exp Med 2021; 218:212714. [PMID: 34670268 PMCID: PMC8532566 DOI: 10.1084/jem.20201314] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/03/2021] [Accepted: 09/29/2021] [Indexed: 11/15/2022] Open
Abstract
The intracellular parasite Toxoplasma gondii has long provided a tractable experimental system to investigate how the immune system deals with intracellular infections. This review highlights the advances in defining how this organism was first detected and the studies with T. gondii that contribute to our understanding of how the cytokine IFN-γ promotes control of vacuolar pathogens. In addition, the genetic tractability of this eukaryote organism has provided the foundation for studies into the diverse strategies that pathogens use to evade antimicrobial responses and now provides the opportunity to study the basis for latency. Thus, T. gondii remains a clinically relevant organism whose evolving interactions with the host immune system continue to teach lessons broadly relevant to host–pathogen interactions.
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Affiliation(s)
- Eva-Maria Frickel
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, UK
| | - Christopher A Hunter
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA
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Tomita T, Guevara RB, Shah LM, Afrifa AY, Weiss LM. Secreted Effectors Modulating Immune Responses to Toxoplasma gondii. Life (Basel) 2021; 11:988. [PMID: 34575137 PMCID: PMC8467511 DOI: 10.3390/life11090988] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/11/2021] [Accepted: 09/13/2021] [Indexed: 12/18/2022] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite that chronically infects a third of humans. It can cause life-threatening encephalitis in immune-compromised individuals. Congenital infection also results in blindness and intellectual disabilities. In the intracellular milieu, parasites encounter various immunological effectors that have been shaped to limit parasite infection. Parasites not only have to suppress these anti-parasitic inflammatory responses but also ensure the host organism's survival until their subsequent transmission. Recent advancements in T. gondii research have revealed a plethora of parasite-secreted proteins that suppress as well as activate immune responses. This mini-review will comprehensively examine each secreted immunomodulatory effector based on the location of their actions. The first section is focused on secreted effectors that localize to the parasitophorous vacuole membrane, the interface between the parasites and the host cytoplasm. Murine hosts are equipped with potent IFNγ-induced immune-related GTPases, and various parasite effectors subvert these to prevent parasite elimination. The second section examines several cytoplasmic and ER effectors, including a recently described function for matrix antigen 1 (MAG1) as a secreted effector. The third section covers the repertoire of nuclear effectors that hijack transcription factors and epigenetic repressors that alter gene expression. The last section focuses on the translocation of dense-granule effectors and effectors in the setting of T. gondii tissue cysts (the bradyzoite parasitophorous vacuole).
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Affiliation(s)
- Tadakimi Tomita
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (T.T.); (R.B.G.)
| | - Rebekah B. Guevara
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (T.T.); (R.B.G.)
| | - Lamisha M. Shah
- Department of Biological Science, Lehman College of the City University of New York, Bronx, NY 10468, USA; (L.M.S.); (A.Y.A.)
| | - Andrews Y. Afrifa
- Department of Biological Science, Lehman College of the City University of New York, Bronx, NY 10468, USA; (L.M.S.); (A.Y.A.)
| | - Louis M. Weiss
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (T.T.); (R.B.G.)
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Chen Y, Liu Q, Xue JX, Zhang MY, Geng XL, Wang Q, Jiang W. Genome-Wide CRISPR/Cas9 Screen Identifies New Genes Critical for Defense Against Oxidant Stress in Toxoplasma gondii. Front Microbiol 2021; 12:670705. [PMID: 34163449 PMCID: PMC8216390 DOI: 10.3389/fmicb.2021.670705] [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: 02/22/2021] [Accepted: 05/03/2021] [Indexed: 11/23/2022] Open
Abstract
Toxoplasma gondii is one of the most widespread apicomplexans and can cause serious infections in humans and animals. Its antioxidant system plays an important role in defending against oxidant stress imposed by the host. Some genes encoding the antioxidant enzymes of T. gondii have been identified; however, critical genes that function in response to reactive oxygen species (ROS) stress are still poorly understood. Here, we performed genome-wide CRISPR/Cas9 loss-of-function screening in the T. gondii RH strain to identify potential genes contributing to the ROS stress response. Under hydrogen peroxide treatment, 30 single guide RNAs targeting high-confidence genes were identified, including some known important antioxidant genes such as catalase and peroxiredoxin PRX3. In addition, several previously uncharacterized genes were identified, among which five hypothetical protein-coding genes, namely, HP1–HP5, were selected for further functional characterization. Targeted deletion of HP1 in T. gondii RH led to significant sensitivity to H2O2, suggesting that HP1 is critical for oxidative stress management. Furthermore, loss of HP1 led to decreased antioxidant capacity, invasion efficiency, and proliferation in vitro. In vivo results also revealed that the survival time of mice infected with the HP1-KO strain was significantly prolonged relative to that of mice infected with the wild-type strain. Altogether, these findings demonstrate that the CRISPR/Cas9 system can be used to identify potential genes critical for oxidative stress management. Furthermore, HP1 may confer protection against oxidative damage and contributes to T. gondii virulence in mice.
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Affiliation(s)
- Yun Chen
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Qi Liu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Jun-Xin Xue
- Shanghai Customs District P. R. C. China, Shanghai, China
| | - Man-Yu Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Xiao-Ling Geng
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Quan Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
| | - Wei Jiang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, China
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Abstract
Obligate intracellular malaria parasites reside within a vacuolar compartment generated during invasion which is the principal interface between pathogen and host. To subvert their host cell and support their metabolism, these parasites coordinate a range of transport activities at this membrane interface that are critically important to parasite survival and virulence, including nutrient import, waste efflux, effector protein export, and uptake of host cell cytosol. Here, we review our current understanding of the transport mechanisms acting at the malaria parasite vacuole during the blood and liver-stages of development with a particular focus on recent advances in our understanding of effector protein translocation into the host cell by the Plasmodium Translocon of EXported proteins (PTEX) and small molecule transport by the PTEX membrane-spanning pore EXP2. Comparison to Toxoplasma gondii and other related apicomplexans is provided to highlight how similar and divergent mechanisms are employed to fulfill analogous transport activities.
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Affiliation(s)
- Josh R. Beck
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Chi-Min Ho
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
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Panas MW, Boothroyd JC. Seizing control: How dense granule effector proteins enable Toxoplasma to take charge. Mol Microbiol 2021; 115:466-477. [PMID: 33400323 PMCID: PMC8344355 DOI: 10.1111/mmi.14679] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/02/2021] [Accepted: 01/03/2021] [Indexed: 12/24/2022]
Abstract
Control of the host cell is crucial to the Apicomplexan parasite, Toxoplasma gondii, while it grows intracellularly. To achieve this goal, these single-celled eukaryotes export a series of effector proteins from organelles known as "dense granules" that interfere with normal cellular processes and responses to invasion. While some effectors are found attached to the outer surface of the parasitophorous vacuole (PV) in which Toxoplasma tachyzoites reside, others are found in the host cell's cytoplasm and yet others make their way into the host nucleus, where they alter host transcription. Among the processes that are severely altered are innate immune responses, host cell cycle, and association with host organelles. The ways in which these crucial processes are altered through the coordinated action of a large collection of effectors is as elegant as it is complex, and is the central focus of the following review; we also discuss the recent advances in our understanding of how dense granule effector proteins are trafficked out of the PV.
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Affiliation(s)
- Michael W. Panas
- Dept. Microbiology and Immunology, Stanford University School of Medicine, Stanford CA 94305
| | - John C. Boothroyd
- Dept. Microbiology and Immunology, Stanford University School of Medicine, Stanford CA 94305
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McGovern OL, Rivera-Cuevas Y, Carruthers VB. Emerging Mechanisms of Endocytosis in Toxoplasma gondii. Life (Basel) 2021; 11:life11020084. [PMID: 33503859 PMCID: PMC7911406 DOI: 10.3390/life11020084] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 02/07/2023] Open
Abstract
Eukaryotes critically rely on endocytosis of autologous and heterologous material to maintain homeostasis and to proliferate. Although mechanisms of endocytosis have been extensively identified in mammalian and plant systems along with model systems including budding yeast, relatively little is known about endocytosis in protozoan parasites including those belonging to the phylum Apicomplexa. Whereas it has been long established that the apicomplexan agents of malaria (Plasmodium spp.) internalize and degrade hemoglobin from infected red blood cells to acquire amino acids for growth, that the related and pervasive parasite Toxoplasma gondii has a functional and active endocytic system was only recently discovered. Here we discuss emerging and hypothesized mechanisms of endocytosis in Toxoplasma gondii with reference to model systems and malaria parasites. Establishing a framework for potential mechanisms of endocytosis in Toxoplasma gondii will help guide future research aimed at defining the molecular basis and biological relevance of endocytosis in this tractable and versatile parasite.
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