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Ying Z, Yin M, Zhu Z, Shang Z, Pei Y, Liu J, Liu Q. Iron Stress Affects the Growth and Differentiation of Toxoplasma gondii. Int J Mol Sci 2024; 25:2493. [PMID: 38473741 DOI: 10.3390/ijms25052493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 02/07/2024] [Accepted: 02/14/2024] [Indexed: 03/14/2024] Open
Abstract
Iron is an indispensable nutrient for the survival of Toxoplasma gondii; however, excessive amounts can lead to toxicity. The parasite must overcome the host's "nutritional immunity" barrier and compete with the host for iron. Since T. gondii can infect most nucleated cells, it encounters increased iron stress during parasitism. This study assessed the impact of iron stress, encompassing both iron depletion and iron accumulation, on the growth of T. gondii. Iron accumulation disrupted the redox balance of T. gondii while enhancing the parasite's ability to adhere in high-iron environments. Conversely, iron depletion promoted the differentiation of tachyzoites into bradyzoites. Proteomic analysis further revealed proteins affected by iron depletion and identified the involvement of phosphotyrosyl phosphatase activator proteins in bradyzoite formation.
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Affiliation(s)
- Zhu Ying
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
| | - Meng Yin
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
| | - Zifu Zhu
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
| | - Zheng Shang
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
| | - Yanqun Pei
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
| | - Jing Liu
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
| | - Qun Liu
- National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing 100083, China
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2
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Sun HC, Deng PM, Fu Y, Deng JH, Xie RH, Huang J, Qi M, Shi TY. Protective efficacy of Toxoplasma gondii GRA12 or GRA7 recombinant proteins encapsulated in PLGA nanoparticles against acute Toxoplasma gondii infection in mice. Front Cell Infect Microbiol 2023; 13:1209755. [PMID: 37502604 PMCID: PMC10368986 DOI: 10.3389/fcimb.2023.1209755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 06/26/2023] [Indexed: 07/29/2023] Open
Abstract
Background Toxoplasma gondii is an apicomplexan parasite that affects the health of humans and livestock, and an effective vaccine is urgently required. Nanoparticles can modulate and improve cellular and humoral immune responses. Methods In the current study, poly (D, L-lactic-co-glycolic acid) (PLGA) nanoparticles were used as a delivery system for the T. gondii dense granule antigens GRA12 and GRA7. BALB/c mice were injected with the vaccines and protective efficacy was evaluated. Results Mice immunized with PLGA+GRA12 exhibited significantly higher IgG, and a noticeable predominance of IgG2a over IgG1 was also observed. There was a 1.5-fold higher level of lymphocyte proliferation in PLGA+GRA12-injected mice compared to Alum+GRA12-immunized mice. Higher levels of IFN-g and IL-10 and a lower level of IL-4 were detected, indicating that Th1 and Th2 immune responses were induced but the predominant response was Th1. There were no significant differences between Alum+GRA7-immunized and PLGA+GRA7-immunized groups. Immunization with these four vaccines resulted in significantly reduced parasite loads, but they were lowest in PLGA+GRA12-immunized mice. The survival times of mice immunized with PLGA+GRA12 were also significantly longer than those of mice in the other vaccinated groups. Conclusion The current study indicated that T. gondii GRA12 recombinant protein encapsulated in PLGA nanoparticles is a promising vaccine against acute toxoplasmosis, but PLGA is almost useless for enhancing the immune response induced by T. gondii GRA7 recombinant protein.
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Affiliation(s)
- Hong-chao Sun
- Institute of Animal Husbandry and Veterinary Medicine, Department of Animal Parasitology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Pu-ming Deng
- Institute of Animal Science and Technology, Department of Animal Diseases Diagnosis and Control of Xinjiang Production & Construction Corps, Tarim University, Alar, China
| | - Yuan Fu
- Institute of Animal Husbandry and Veterinary Medicine, Department of Animal Parasitology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Jin-hua Deng
- Institute of Animal Science and Technology, Department of Animal Diseases Diagnosis and Control of Xinjiang Production & Construction Corps, Tarim University, Alar, China
| | - Rong-hui Xie
- Department of Animal Epidemic Surveillance, Zhejiang Provincial Animal Disease Prevention and Control Center, Hangzhou, China
| | - Jing Huang
- Department of Animal Epidemic Surveillance, Zhejiang Provincial Animal Disease Prevention and Control Center, Hangzhou, China
| | - Meng Qi
- Institute of Animal Science and Technology, Department of Animal Diseases Diagnosis and Control of Xinjiang Production & Construction Corps, Tarim University, Alar, China
| | - Tuan-yuan Shi
- Institute of Animal Husbandry and Veterinary Medicine, Department of Animal Parasitology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
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3
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Sparvoli D, Delabre J, Penarete‐Vargas DM, Kumar Mageswaran S, Tsypin LM, Heckendorn J, Theveny L, Maynadier M, Mendonça Cova M, Berry‐Sterkers L, Guérin A, Dubremetz J, Urbach S, Striepen B, Turkewitz AP, Chang Y, Lebrun M. An apical membrane complex for triggering rhoptry exocytosis and invasion in Toxoplasma. EMBO J 2022; 41:e111158. [PMID: 36245278 PMCID: PMC9670195 DOI: 10.15252/embj.2022111158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 09/13/2022] [Accepted: 09/19/2022] [Indexed: 01/13/2023] Open
Abstract
Apicomplexan parasites possess secretory organelles called rhoptries that undergo regulated exocytosis upon contact with the host. This process is essential for the parasitic lifestyle of these pathogens and relies on an exocytic machinery sharing structural features and molecular components with free-living ciliates. However, how the parasites coordinate exocytosis with host interaction is unknown. Here, we performed a Tetrahymena-based transcriptomic screen to uncover novel exocytic factors in Ciliata and conserved in Apicomplexa. We identified membrane-bound proteins, named CRMPs, forming part of a large complex essential for rhoptry secretion and invasion in Toxoplasma. Using cutting-edge imaging tools, including expansion microscopy and cryo-electron tomography, we show that, unlike previously described rhoptry exocytic factors, TgCRMPs are not required for the assembly of the rhoptry secretion machinery and only transiently associate with the exocytic site-prior to the invasion. CRMPs and their partners contain putative host cell-binding domains, and CRMPa shares similarities with GPCR proteins. Collectively our data imply that the CRMP complex acts as a host-molecular sensor to ensure that rhoptry exocytosis occurs when the parasite contacts the host cell.
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Affiliation(s)
- Daniela Sparvoli
- Laboratory of Pathogen Host InteractionsUMR 5235 CNRS, Université de MontpellierMontpellierFrance
| | - Jason Delabre
- Laboratory of Pathogen Host InteractionsUMR 5235 CNRS, Université de MontpellierMontpellierFrance
| | | | - Shrawan Kumar Mageswaran
- Department of Biochemistry and Biophysics, Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Lev M Tsypin
- Department of Molecular Genetics and Cell BiologyUniversity of ChicagoChicagoILUSA
- Present address:
Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Justine Heckendorn
- Laboratory of Pathogen Host InteractionsUMR 5235 CNRS, Université de MontpellierMontpellierFrance
| | - Liam Theveny
- Department of Biochemistry and Biophysics, Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Marjorie Maynadier
- Laboratory of Pathogen Host InteractionsUMR 5235 CNRS, Université de MontpellierMontpellierFrance
| | - Marta Mendonça Cova
- Laboratory of Pathogen Host InteractionsUMR 5235 CNRS, Université de MontpellierMontpellierFrance
| | - Laurence Berry‐Sterkers
- Laboratory of Pathogen Host InteractionsUMR 5235 CNRS, Université de MontpellierMontpellierFrance
| | - Amandine Guérin
- Department of Pathobiology, School of Veterinary MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Jean‐François Dubremetz
- Laboratory of Pathogen Host InteractionsUMR 5235 CNRS, Université de MontpellierMontpellierFrance
| | - Serge Urbach
- IGFUniversité de Montpellier, CNRS, INSERMMontpellierFrance
| | - Boris Striepen
- Department of Pathobiology, School of Veterinary MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Aaron P Turkewitz
- Department of Molecular Genetics and Cell BiologyUniversity of ChicagoChicagoILUSA
| | - Yi‐Wei Chang
- Department of Biochemistry and Biophysics, Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Maryse Lebrun
- Laboratory of Pathogen Host InteractionsUMR 5235 CNRS, Université de MontpellierMontpellierFrance
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4
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Munera Lopez J, Tengganu IF, Liu J, Murray JM, Arias Padilla LF, Zhang Y, Brown PT, Florens L, Hu K. An apical protein, Pcr2, is required for persistent movement by the human parasite Toxoplasma gondii. PLoS Pathog 2022; 18:e1010776. [PMID: 35994509 PMCID: PMC9436145 DOI: 10.1371/journal.ppat.1010776] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 09/01/2022] [Accepted: 07/28/2022] [Indexed: 11/18/2022] Open
Abstract
The phylum Apicomplexa includes thousands of species of unicellular parasites that cause a wide range of human and animal diseases such as malaria and toxoplasmosis. To infect, the parasite must first initiate active movement to disseminate through tissue and invade into a host cell, and then cease moving once inside. The parasite moves by gliding on a surface, propelled by an internal cortical actomyosin-based motility apparatus. One of the most effective invaders in Apicomplexa is Toxoplasma gondii, which can infect any nucleated cell and any warm-blooded animal. During invasion, the parasite first makes contact with the host cell "head-on" with the apical complex, which features an elaborate cytoskeletal apparatus and associated structures. Here we report the identification and characterization of a new component of the apical complex, Preconoidal region protein 2 (Pcr2). Pcr2 knockout parasites replicate normally, but they are severely diminished in their capacity for host tissue destruction due to significantly impaired invasion and egress, two vital steps in the lytic cycle. When stimulated for calcium-induced egress, Pcr2 knockout parasites become active, and secrete effectors to lyse the host cell. Calcium-induced secretion of the major adhesin, MIC2, also appears to be normal. However, the movement of the Pcr2 knockout parasite is spasmodic, which drastically compromises egress. In addition to faulty motility, the ability of the Pcr2 knockout parasite to assemble the moving junction is impaired. Both defects likely contribute to the poor efficiency of invasion. Interestingly, actomyosin activity, as indicated by the motion of mEmerald tagged actin chromobody, appears to be largely unperturbed by the loss of Pcr2, raising the possibility that Pcr2 may act downstream of or in parallel with the actomyosin machinery.
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Affiliation(s)
- Jonathan Munera Lopez
- Biodesign Center for Mechanisms of Evolution/School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Isadonna F. Tengganu
- Biodesign Center for Mechanisms of Evolution/School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Jun Liu
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - John M. Murray
- Biodesign Center for Mechanisms of Evolution/School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Luisa F. Arias Padilla
- Biodesign Center for Mechanisms of Evolution/School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Ying Zhang
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Peter T. Brown
- Department of Physics and Center for Biological Physics, Arizona State University, Tempe, Arizona, United States of America
| | - Laurence Florens
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Ke Hu
- Biodesign Center for Mechanisms of Evolution/School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- * E-mail:
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5
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Valenzuela-Moreno LF, Carmona-Muciño MDC, Cedillo-Peláez C, Rico-Torres CP, Luna-Pastén H, Hernández-Rodríguez MA, Caballero-Ortega H. Acute Disseminated Toxoplasmosis in Two Specimens of Macropus rufogriseus Caused by a Genotype so far Exclusive to South America. Front Vet Sci 2022; 9:923976. [PMID: 35782563 PMCID: PMC9240756 DOI: 10.3389/fvets.2022.923976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 05/23/2022] [Indexed: 11/17/2022] Open
Abstract
Macropods are included among the species considered highly susceptible to Toxoplasma gondii infection. Clinically, it is difficult to distinguish between acute toxoplasmosis due to primary infection and reactivation of chronic latent infection in susceptible species until pathologic studies are performed. Here, we described the clinical cases and lesions found in two deceased Bennett's wallabies (Macropus rufogriseus) with a presumptive diagnosis of toxoplasmosis, as well as the genetic characterization of the T. gondii isolates obtained from these specimens. Both animals presented acute infection lesions in the lungs, liver, spleen and lymph nodes associated to T. gondii infection. Histopathology and immunohistochemistry also demonstrated tissue cysts of different sizes, indicating that the wallabies were previously infected with this parasite. Two isolates were obtained, one from each specimen and the molecular characterization was done; both isolates were the ToxoDB #116 genotype. This is the first study that reports the isolation of this particular genotype outside South America, and given the histopathological findings, it could be considered virulent for this species. The dynamics of infection that T. gondii is causing in definitive and intermediate hosts in a region allows us to know the risks to which the animals and humans that live in the area are exposed, and in the future to implement a preventive medicine plan against this parasite.
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Affiliation(s)
- Luis Fernando Valenzuela-Moreno
- Laboratorio de Inmunología Experimental, Instituto Nacional de Pediatría, Insurgentes Sur 3700-C, Colonia Insurgentes-Cuicuilco, Demarcación Territorial Coyoacán, Ciudad de México, Mexico
| | | | - Carlos Cedillo-Peláez
- Laboratorio de Inmunología Experimental, Instituto Nacional de Pediatría, Insurgentes Sur 3700-C, Colonia Insurgentes-Cuicuilco, Demarcación Territorial Coyoacán, Ciudad de México, Mexico
| | - Claudia Patricia Rico-Torres
- Laboratorio de Inmunología Experimental, Instituto Nacional de Pediatría, Insurgentes Sur 3700-C, Colonia Insurgentes-Cuicuilco, Demarcación Territorial Coyoacán, Ciudad de México, Mexico
| | - Héctor Luna-Pastén
- Laboratorio de Inmunología Experimental, Instituto Nacional de Pediatría, Insurgentes Sur 3700-C, Colonia Insurgentes-Cuicuilco, Demarcación Territorial Coyoacán, Ciudad de México, Mexico
| | | | - Heriberto Caballero-Ortega
- Laboratorio de Inmunología Experimental, Instituto Nacional de Pediatría, Insurgentes Sur 3700-C, Colonia Insurgentes-Cuicuilco, Demarcación Territorial Coyoacán, Ciudad de México, Mexico
- *Correspondence: Heriberto Caballero-Ortega
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6
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Nagai K, Goto Y. Parasitomimetics: Can We Utilize Parasite-Derived Immunomodulatory Molecules for Interventions to Immunological Disorders? Front Immunol 2022; 13:824695. [PMID: 35386686 PMCID: PMC8977410 DOI: 10.3389/fimmu.2022.824695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 02/28/2022] [Indexed: 11/17/2022] Open
Abstract
Because our immune system has ability to expel microorganisms invading our body, parasites need evolution to maintain their symbiosis with the hosts. One such strategy of the parasites is to manipulate host immunity by producing immunomodulatory molecules and the ability of parasites to regulate host immunity has long been a target of research. Parasites can not only manipulate host immune response specific to them, but also influence the host's entire immune system. Such ability of the parasites may sometimes bring benefit to the hosts as many studies have indicated the "hygiene hypothesis" that a decreased opportunity of parasitic infections is associated with an increased incidence of allergy and autoimmune diseases. In other words, elucidating the mechanisms of parasites to regulate host immunity could be applied not only to resolution of parasitic infections but also to treatment of non-parasitic immunological disorders. In this review, we show how much progress has been made in the research on immunomodulation of host immunity by parasites. Here, we define the word 'parasitomimetics' as emulation of parasites' immunomodulatory systems to solve immunological problems in humans and discuss potential applications of parasite-derived molecules to other diseases.
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Affiliation(s)
| | - Yasuyuki Goto
- Laboratory of Molecular Immunology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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7
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Stadler RV, Nelson SR, Warshaw DM, Ward GE. A circular zone of attachment to the extracellular matrix provides directionality to the motility of Toxoplasma gondii in 3D. eLife 2022; 11:85171. [PMID: 36519527 PMCID: PMC9839348 DOI: 10.7554/elife.85171] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
Toxoplasma gondii is a protozoan parasite that infects 30-40% of the world's population. Infections are typically subclinical but can be severe and, in some cases, life threatening. Central to the virulence of T. gondii is an unusual form of substrate-dependent motility that enables the parasite to invade cells of its host and to disseminate throughout the body. A hetero-oligomeric complex of proteins that functions in motility has been characterized, but how these proteins work together to drive forward motion of the parasite remains controversial. A key piece of information needed to understand the underlying mechanism(s) is the directionality of the forces that a moving parasite exerts on the external environment. The linear motor model of motility, which has dominated the field for the past two decades, predicts continuous anterior-to-posterior force generation along the length of the parasite. We show here using three-dimensional traction force mapping that the predominant forces exerted by a moving parasite are instead periodic and directed in toward the parasite at a fixed circular location within the extracellular matrix. These highly localized forces, which are generated by the parasite pulling on the matrix, create a visible constriction in the parasite's plasma membrane. We propose that the ring of inward-directed force corresponds to a circumferential attachment zone between the parasite and the matrix, through which the parasite propels itself to move forward. The combined data suggest a closer connection between the mechanisms underlying parasite motility and host cell invasion than previously recognized. In parasites lacking the major surface adhesin, TgMIC2, neither the inward-directed forces nor the constriction of the parasite membrane are observed. The trajectories of the TgMIC2-deficient parasites are less straight than those of wild-type parasites, suggesting that the annular zone of TgMIC2-mediated attachment to the extracellular matrix normally constrains the directional options available to the parasite as it migrates through its surrounding environment.
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Affiliation(s)
- Rachel V Stadler
- Department of Microbiology and Molecular Genetics, University of Vermont Larner College of MedicineBurlingtonUnited States
| | - Shane R Nelson
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of MedicineBurlingtonUnited States
| | - David M Warshaw
- Department of Molecular Physiology and Biophysics, University of Vermont Larner College of MedicineBurlingtonUnited States
| | - Gary E Ward
- Department of Microbiology and Molecular Genetics, University of Vermont Larner College of MedicineBurlingtonUnited States
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8
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Liu X, Li C, Li X, Ehsan M, Lu M, Li K, Xu L, Yan R, Song X, Li X. Proteomics analysis reveals that the proto-oncogene eIF-5A indirectly influences the growth, invasion and replication of Toxoplasma gondii tachyzoite. Parasit Vectors 2021; 14:283. [PMID: 34039408 PMCID: PMC8157420 DOI: 10.1186/s13071-021-04791-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 05/11/2021] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The proliferative stage (tachyzoite) of Toxoplasma gondii (T. gondii) is critical for its transmission and pathogenesis, and a proto-oncogene eukaryotic translation initiation factor (eIF-5A) plays an important role in various cellular processes such as cell multiplication. METHODS We performed a proteomic study to evaluate the specific roles of eIF-5A involved in invasion and replication of T. gondii, and both in vivo and in vitro trials using eIF-5A-interfered and wild tachyzoites were performed to verify the proteomic results. RESULTS The results of our study showed that T. gondii eIF-5A affected tachyzoite growth and also participated in the synthesis of proteins through regulation of both ribosomal and splicing pathways. Inhibition of eIF-5A in T. gondii resulted in the downregulated expression of soluble adhesions, such as microneme protein 1 (MIC1) and MIC4, which in turn decreased the parasite population that adhered to the surface of host cells. The reduced attachment, combined with lower expression of some rhoptry proteins (ROPs) and dense granule antigens (GRAs) involved in different stages of T. gondii invasion such as ROP4 and GRA3, ultimately reduce the invasion efficiency. These processes regulated by eIF-5A eventually affect the replication of tachyzoites. CONCLUSIONS Our findings showed that eIF-5A influenced tachyzoite survival and was also involved in the process of parasite invasion and replication. These results will provide new clues for further development of targeted drugs to control T. gondii infection.
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Affiliation(s)
- Xinchao Liu
- Anhui Province Key Laboratory of Animal Nutritional Regulation and Health, College of Animal Science, Anhui Science and Technology University, Fengyang, 233100 People’s Republic of China
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 People’s Republic of China
| | - Chunjing Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 People’s Republic of China
| | - Xiaoyu Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 People’s Republic of China
| | - Muhammad Ehsan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 People’s Republic of China
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046 Gansu People’s Republic of China
| | - Mingmin Lu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 People’s Republic of China
| | - Ke Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 People’s Republic of China
- Poultry and Poultry Diseases Institute, Yunnan Animal Science and Veterinary Institute, Kunming, 650224 People’s Republic of China
| | - Lixin Xu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 People’s Republic of China
| | - Ruofeng Yan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 People’s Republic of China
| | - Xiaokai Song
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 People’s Republic of China
| | - XiangRui Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095 People’s Republic of China
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9
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Jadavi S, Bianchini P, Cavalleri O, Dante S, Canale C, Diaspro A. Correlative nanoscopy: A multimodal approach to molecular resolution. Microsc Res Tech 2021; 84:2472-2482. [PMID: 33955625 PMCID: PMC8518117 DOI: 10.1002/jemt.23800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 04/11/2021] [Indexed: 11/24/2022]
Abstract
Atomic force microscopy (AFM) is a nano‐mechanical tool uniquely suited for biological studies at the molecular scale. AFM operation is based on mechanical interaction between the tip and the sample, a mechanism of contrast capable of measuring different information, including surface topography, mechanical, and electrical properties. However, the lack of specificity highlights the need to integrate AFM data with other techniques providing compositional hints. In particular, optical microscopes based on fluorescence as a mechanism of contrast can access the local distribution of specific molecular species. The coupling between AFM and super‐resolved fluorescence microscopy solves the resolution mismatch between AFM and conventional fluorescence optical microscopy. Recent advances showed that also the inherently label‐free imaging capabilities of the AFM are fundamental to complement the fluorescence images. In this review, we have presented a brief historical view on correlative microscopy, and, finally, we have summarized the progress of correlative AFM‐super‐resolution microscopy in biological research.
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Affiliation(s)
- Samira Jadavi
- DIFILAB, Department of Physics, University of Genova, Genova, Italy.,Nanoscopy, CHT Erzelli, Istituto Italiano di Tecnologia, Genova, Italy
| | - Paolo Bianchini
- Nanoscopy, CHT Erzelli, Istituto Italiano di Tecnologia, Genova, Italy
| | | | - Silvia Dante
- Materials Characterization Facility, Istituto Italiano di Tecnologia, Genova, Italy
| | - Claudio Canale
- DIFILAB, Department of Physics, University of Genova, Genova, Italy
| | - Alberto Diaspro
- DIFILAB, Department of Physics, University of Genova, Genova, Italy.,Nanoscopy, CHT Erzelli, Istituto Italiano di Tecnologia, Genova, Italy
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10
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Ihara F, Nishikawa Y. Toxoplasma gondii manipulates host cell signaling pathways via its secreted effector molecules. Parasitol Int 2021; 83:102368. [PMID: 33905814 DOI: 10.1016/j.parint.2021.102368] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 03/13/2021] [Accepted: 04/07/2021] [Indexed: 01/07/2023]
Abstract
The obligate intracellular parasite Toxoplasma gondii secretes a vast variety of effector molecules from organelles known as rhoptries (ROPs) and dense granules (GRAs). ROP proteins are released into the cytosol of the host cell where they are directed to the cell nucleus or to the parasitophorous vacuole (PV) membrane. ROPs secrete proteins that enable host cell penetration and vacuole formation by the parasites, as well as hijacking host-immune responses. After invading host cells, T. gondii multiplies within a PV that is maintained by the parasite proteins secreted from GRAs. Most GRA proteins remain within the PV, but some are known to access the host cytosol across the PV membrane, and a few are able to traffic into the host-cell nucleus. These effectors bind to host cell proteins and affect host cell signaling pathways to favor the parasite. Studies on host-pathogen interactions have identified many infection-altered host signal transductions. Notably, the relationship between individual parasite effector molecules and the specific targeting of host-signaling pathways is being elucidated through the advent of forward and reverse genetic strategies. Understanding the complex nature of the host-pathogen interactions underlying how the host-signaling pathway is manipulated by parasite effectors may lead to new molecular biological knowledge and novel therapeutic methods for toxoplasmosis. In this review, we discuss how T. gondii modulates cell signaling pathways in the host to favor its survival.
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Affiliation(s)
- Fumiaki Ihara
- Molecular Parasitology Section, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States.
| | - Yoshifumi Nishikawa
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan.
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11
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Attias M, Teixeira DE, Benchimol M, Vommaro RC, Crepaldi PH, De Souza W. The life-cycle of Toxoplasma gondii reviewed using animations. Parasit Vectors 2020; 13:588. [PMID: 33228743 PMCID: PMC7686686 DOI: 10.1186/s13071-020-04445-z] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 10/30/2020] [Indexed: 11/21/2022] Open
Abstract
Toxoplasma gondii is a protozoan parasite that is the causative agent of toxoplasmosis, an infection with high prevalence worldwide. Most of the infected individuals are either asymptomatic or have mild symptoms, but T. gondii can cause severe neurologic damage and even death of the fetus when acquired during pregnancy. It is also a serious condition in immunodeficient patients. The life-cycle of T. gondii is complex, with more than one infective form and several transmission pathways. In two animated videos, we describe the main aspects of this cycle, raising questions about poorly or unknown issues of T. gondii biology. Original plates, based on electron microscope observations, are also available for teachers, students and researchers. The main goal of this review is to provide a source of learning on the fundamental aspects of T. gondii biology to students and teachers contributing for better knowledge and control on this important parasite, and unique cell model. In addition, drawings and videos point to still unclear aspects of T. gondii lytic cycle that may stimulate further studies.![]()
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Affiliation(s)
- Márcia Attias
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. .,Centro Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
| | | | | | - Rossiane C Vommaro
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Paulo Henrique Crepaldi
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Wanderley De Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Centro Nacional de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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12
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Acosta-Dávila A, Acosta-Espinel A, Hernández-de-Los-Ríos A, Gómez-Marín JE. Human peripheral blood mononuclear cells as an ex vivo model to study the host parasite interaction in Toxoplasma gondii. Exp Parasitol 2020; 219:108020. [PMID: 33058858 DOI: 10.1016/j.exppara.2020.108020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 10/05/2020] [Accepted: 10/09/2020] [Indexed: 10/23/2022]
Abstract
Toxoplasma gondii is a parasite that can invade any cell in the human body. Here, we implemented and described an ex vivo model with human peripheral blood mononuclear cells (PBMCs) without using culture supplements/antibiotics and without cryopreserved cells (EXMOWS) to study the interactions between T. gondii and human cells. To establish the EXMOWS, three independent tests were carried out. Firstly, blood samples from 5 individuals were included to assess the viability and adherence of PBMCs in plate culture. In a second trial, blood samples from three seropositive and two seronegative individuals for T. gondii were used to evaluate human PBMCs cells: parasites, multiplicity of infection (MOI) 1:1, 1:3 and 1:5 at different times post infection (1 h, 6 h and 24 h). The possible immunomodulatory effect of the infection for this EXMOWS were evaluated in a third trial where HFF cells were infected with T. gondii and co-cultured with PBMCs obtained from anti-Toxoplasma IgG positive and IgG negative individuals. One hour was enough time for T. gondii infection of human PBMCs and 2 h was the minimum incubation time to guarantee adherence before carrying out any infection assay. A minimum of 1:3 MOI was necessary to guarantee efficient infection in human PBMCs with T. gondii RH-GFP. All protocols, including PBMCs isolation and stimulation, should be conducted the same day. This EXMOWS can be adapted to study the early stages of interaction with other microorganisms of human interest, without need of using cryopreservation and supplements/antibiotics.
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Affiliation(s)
- Alejandro Acosta-Dávila
- Grupo GEPAMOL, Centro de Investigaciones Biomédicas, Facultad de Ciencias de La Salud, Universidad Del Quindio, Colombia
| | - Alejandra Acosta-Espinel
- Grupo GEPAMOL, Centro de Investigaciones Biomédicas, Facultad de Ciencias de La Salud, Universidad Del Quindio, Colombia
| | | | - Jorge Enrique Gómez-Marín
- Grupo GEPAMOL, Centro de Investigaciones Biomédicas, Facultad de Ciencias de La Salud, Universidad Del Quindio, Colombia.
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13
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Li J, Ma YT, Liang QL, Li RL, Zheng FG, Liu Q, Zhu XQ, Gao WW. Serological evidence of Toxoplasma gondii and Chlamydia infection in alpacas (Vicugna pacos) in Shanxi Province, northern China. Microb Pathog 2020; 149:104399. [PMID: 32693119 DOI: 10.1016/j.micpath.2020.104399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 07/11/2020] [Accepted: 07/13/2020] [Indexed: 11/18/2022]
Abstract
Toxoplasma gondii, Neospora caninum, Chlamydia and bluetongue virus (BTV) are four important pathogens which can cause reproductive loss. The present study was conducted to estimate the seroprevalence of T. gondii, N. caninum, Chlamydia and BTV in alpacas in Shanxi Province, northern China. A total of 251 serum samples were collected from alpacas, and antibodies against T. gondii and Chlamydia were examined by the modified agglutination test (MAT) and indirect hemagglutination assay (IHA), respectively. Antibodies to N. caninum and BTV were determined by using the commercially available competitive enzyme-linked immunosorbent assay (cELISA) kits, respectively. The overall seroprevalence of T. gondii was 9.16% (95% CI 5.59-12.73) in the three sampled counties, of which, no T. gondii-seropositive samples were detected in alpacas in Fanshi County. Gender differences in the T. gondii seroprevalence were observed. The overall Chlamydia seroprevalence was 13.94% (95% CI: 9.66-18.22), and there was a statistically significant difference in Chlamydia seroprevalence in alpacas between the two counties, Jiexiu and Fanshi. All serum samples tested negative for N. caninum and BTV antibodies, respectively. To our knowledge, this is the first report of T. gondii and Chlamydia seroprevalence in alpacas in China, which provides baseline information for controlling T. gondii and Chlamydia infection in alpacas in China.
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Affiliation(s)
- Jin Li
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, PR China.
| | - Ye-Ting Ma
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, PR China; State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, PR China.
| | - Qin-Li Liang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, PR China.
| | - Run-Li Li
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, PR China.
| | - Fu-Guo Zheng
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, PR China.
| | - Qing Liu
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, PR China.
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, PR China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University College of Veterinary Medicine, Yangzhou, Jiangsu Province, 225009, PR China.
| | - Wen-Wei Gao
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, PR China.
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Li R, Ma Y, Li J, Zhou P, Zheng F, Liu Q, Gao W. Application of Toxoplasma gondii GRA15 peptides in diagnosis and serotyping. Microb Pathog 2020; 143:104168. [PMID: 32205209 DOI: 10.1016/j.micpath.2020.104168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 03/06/2020] [Accepted: 03/17/2020] [Indexed: 12/22/2022]
Abstract
Previous studies showed that three clonal strain types (I, II, and III) of Toxoplasma gondii can be distinguished using serotyping based on a series of polymorphic proteins. However, to establish a systematic serotyping method with higher resolution even being equal to that of genotyping, more specific peptide markers are needed. The objective of the present study was to determine the possibility of the polymorphic dense granule protein 15 (GRA15) for diagnosis and serotyping of T. gondii infection. Three different T. gondii GT1 strain GRA15 gene fragments encoding a 584-residue peptide, a 199-residue peptide and a 84-residue peptide were amplified, expressed and purified, respectively. Anti-T. gondii GT1 strain antibodies, anti-T. gondii RH strain antibodies and anti-T. gondii PRU strain antibodies were used for immunoblotting analysis of the three peptides. Western blotting analysis showed that the 584-residue peptide of GT1 strain GRA15 was a potential candidate for serological diagnosis of T. gondii infection. RH strain from GT1 strain could be distinguished by serotyping based on the GRA15199 or GRA1584, and T. gondii GT1 strain could be distinguished from PRU strain by using serotyping based on the GRA1584. These findings reveal, for the first time, a novel potential role of GRA15-derived peptides in diagnosis and serological differentiation of T. gondii infection.
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Affiliation(s)
- Runli Li
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, PR China
| | - Yeting Ma
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, PR China
| | - Jin Li
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, PR China
| | - Penglai Zhou
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, PR China
| | - Fuguo Zheng
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, PR China
| | - Qing Liu
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, PR China.
| | - Wenwei Gao
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, PR China.
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15
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Lee J, Choi JW, Han HY, Kim WS, Song HY, Byun EB, Byun EH, Lee YH, Yuk JM. 4-Hydroxybenzaldehyde Restricts the Intracellular Growth of Toxoplasma gondii by Inducing SIRT1-Mediated Autophagy in Macrophages. THE KOREAN JOURNAL OF PARASITOLOGY 2020; 58:7-14. [PMID: 32145722 PMCID: PMC7066436 DOI: 10.3347/kjp.2020.58.1.7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 11/04/2019] [Indexed: 12/20/2022]
Abstract
Toxoplasma gondii is an intracellular protozoan parasite that infects approximately one third of the human popu- lation worldwide. Considering the toxicity and side effects of anti-toxoplasma medications, it is important to develop effec- tive drug alternatives with fewer and less severe off-target effects. In this study, we found that 4-hydroxybenzaldehyde (4- HBA) induced autophagy and the expression of NAD-dependent protein deacetylase sirtuin-1 (SIRT1) in primary murine bone marrow-derived macrophages (BMDMs). Interestingly, treatment of BMDMs with 4-HBA significantly reduced the number of macrophages infected with T. gondii and the proliferation of T. gondii in infected cells. This effect was impaired by pretreating the macrophages with 3-methyladenine or wortmannin (selective autophagy inhibitors) or with sirtinol or EX527 (SIRT1 inhibitors). Moreover, we found that pharmacological inhibition of SIRT1 prevented 4-HBA-mediated expres- sion of LC3-phosphatidylethanolamine conjugate (LC3-II) and the colocalization of T. gondii parasitophorous vacuoles with autophagosomes in BMDMs. These data suggest that 4-HBA promotes antiparasitic host responses by activating SIRT1- mediated autophagy, and 4-HBA might be a promising therapeutic alternative for the treatment of toxoplasmosis.
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Affiliation(s)
- Jina Lee
- Department of Infection Biology and Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea.,Infection Control Convergence Research Center, College of Medicine, Chungnam National University, Daejeon 35015, Korea
| | - Jae-Won Choi
- Department of Infection Biology and Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea.,Infection Control Convergence Research Center, College of Medicine, Chungnam National University, Daejeon 35015, Korea
| | - Hye Young Han
- Department of Infection Biology and Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea
| | - Woo Sik Kim
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 56212, Korea
| | - Ha-Yeon Song
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 56212, Korea
| | - Eui-Baek Byun
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 56212, Korea
| | - Eui-Hong Byun
- Department of Food Science and Technology, Kongju National University, Yesan 32439, Korea
| | - Young-Ha Lee
- Department of Infection Biology and Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea
| | - Jae-Min Yuk
- Department of Infection Biology and Medical Science, College of Medicine, Chungnam National University, Daejeon 35015, Korea.,Infection Control Convergence Research Center, College of Medicine, Chungnam National University, Daejeon 35015, Korea
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Omega-3 Polyunsaturated Fatty Acids Prevent Toxoplasma gondii Infection by Inducing Autophagy via AMPK Activation. Nutrients 2019; 11:nu11092137. [PMID: 31500218 PMCID: PMC6771136 DOI: 10.3390/nu11092137] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 08/30/2019] [Accepted: 09/04/2019] [Indexed: 12/11/2022] Open
Abstract
Omega-3 polyunsaturated fatty acids (ω3-PUFAs) have potential protective activity in a variety of infectious diseases, but their actions and underlying mechanisms in Toxoplasma gondii infection remain poorly understood. Here, we report that docosahexaenoic acid (DHA) robustly induced autophagy in murine bone marrow-derived macrophages (BMDMs). Treatment of T. gondii-infected macrophages with DHA resulted in colocalization of Toxoplasma parasitophorous vacuoles with autophagosomes and reduced intracellular survival of T. gondii. The autophagic and anti-Toxoplasma effects induced by DHA were mediated by AMP-activated protein kinase (AMPK) signaling. Importantly, BMDMs isolated from Fat-1 transgenic mice, a well-known animal model capable of synthesizing ω3-PUFAs from ω6-PUFAs, showed increased activation of autophagy and AMPK, leading to reduced intracellular survival of T. gondii when compared with wild-type BMDMs. Moreover, Fat-1 transgenic mice exhibited lower cyst burden in the brain following infection with the avirulent strain ME49 than wild-type mice. Collectively, our results revealed mechanisms by which endogenous ω3-PUFAs and DHA control T. gondii infection and suggest that ω3-PUFAs might serve as therapeutic candidate to prevent toxoplasmosis and infection with other intracellular protozoan parasites.
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Protective effects of a traditional herbal extract from Stellaria dichotoma var. lanceolata against Mycobacterium abscessus infections. PLoS One 2018; 13:e0207696. [PMID: 30452471 PMCID: PMC6242687 DOI: 10.1371/journal.pone.0207696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 11/05/2018] [Indexed: 11/24/2022] Open
Abstract
Stellaria dichotoma var. lanceolata (SdLv), a member of the Caryophyllaceae, is a traditional herbal medicine that has been used to treat fever, night sweats, and malaria in East Asia. Inflammation plays an essential role in both host defense and pathogenesis during infection by diverse intracellular pathogens. Herein, we showed that an herbal extract from SdLv effectively attenuated inflammatory responses from infection of Mycobacterium abscessus (Mab), but not Toxoplasma gondii (T. gondii). In primary murine macrophages, Mab infection resulted in the rapid activation of nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK), as well as in the generation of proinflammatory cytokines, such as tumor necrosis factor α and interleukin-6, which were all significantly inhibited by pretreatment with SdLv. However, herbal extracts from Bupleurum chinense DC. (Buch) or Bupleurum falcatum L. (Bufa) did not affect M. abs-induced activation of proinflammatory responses. Importantly, we demonstrated that generation of intracellular reactive oxygen species, which are important signaling intermediaries in the activation of NF-κB and the MAPK signaling pathway, was rapidly increased in Mab-infected macrophages, and this was effectively suppressed by pretreatment with SdLv, but not Buch and Bufa. We further found that the treatment of Buch and Bufa, but not SdLv, led to the activation of NF-κB and the MAPK signaling pathway and the generation of intracellular reactive oxygen species. Moreover, oral administration of SdLv significantly reduced lethality in Mab-infected mice. Collectively, these results suggest the possible use of SdLv as an effective treatment for Mab infection.
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Liu Q, Gao WW, Elsheikha HM, He JJ, Li FC, Yang WB, Zhu XQ. Transcriptomic analysis reveals Toxoplasma gondii strain-specific differences in host cell response to dense granule protein GRA15. Parasitol Res 2018; 117:2785-2793. [PMID: 29916065 DOI: 10.1007/s00436-018-5966-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 06/08/2018] [Indexed: 11/27/2022]
Abstract
Growth and replication of the protozoan parasite Toxoplasma gondii within host cell entail the production of several effector proteins, which the parasite exploits for counteracting the host's immune response. Despite considerable research to define the host signaling pathways manipulated by T. gondii and their effectors, there has been limited progress into understanding how individual members of the dense granule proteins (GRAs) modulate gene expression within host cells. The aim of this study was to evaluate whether T. gondii GRA15 protein plays any role in regulating host gene expression. Baby hamster kidney cells (BHK-21) were transfected with plasmids encoding GRA15 genes of either type I GT1 strain (GRA15I) or type II PRU strain (GRA15II). Gene expression patterns of transfected and nontransfected BHK-21 cells were investigated using RNA-sequencing analysis. GRA15I and GRA15II induced both known and novel transcriptional changes in the transfected BHK-21 cells compared with nontransfected cells. Pathway analysis revealed that GRA15II was mainly involved in the regulation of tumor necrosis factor (TNF), NF-κB, HTLV-I infection, and NOD-like receptor signaling pathways. GRA15I preferentially influenced the synthesis of unsaturated fatty acids in host cells. Our findings support the hypothesis that certain functions of GRA15 protein are strain dependent and that GRA15 modulates the expression of signaling pathways and genes with important roles in T. gondii pathophysiology. A greater understanding of host signaling pathways influenced by T. gondii effectors would allow the development of more efficient anti-T. gondii therapeutic schemes, capitalizing on disrupting parasite virulence factors to advance the treatment of toxoplasmosis.
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Affiliation(s)
- Qing Liu
- State Key Laboratory of Veterinary Etiological Biology, 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
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, People's Republic of China
| | - Wen-Wei Gao
- College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, 030801, 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
| | - Jun-Jun He
- State Key Laboratory of Veterinary Etiological Biology, 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.
| | - Fa-Cai Li
- State Key Laboratory of Veterinary Etiological Biology, 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
| | - Wen-Bin Yang
- State Key Laboratory of Veterinary Etiological Biology, 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
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, 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
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Wei W, Zhang F, Chen H, Tang Y, Xing T, Luo Q, Yu L, Du J, Shen J, Zhang L. Toxoplasma gondii dense granule protein 15 induces apoptosis in choriocarcinoma JEG-3 cells through endoplasmic reticulum stress. Parasit Vectors 2018; 11:251. [PMID: 29665822 PMCID: PMC5904991 DOI: 10.1186/s13071-018-2835-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/06/2018] [Indexed: 12/20/2022] Open
Abstract
Background Toxoplasma gondii, a single-celled parasite commonly found in mammals, has been shown to induce trophoblast cell apoptosis and subsequently cause fetal damage and abortion. Although dense granule protein 15 (GRA15) has been identified as a key component in innate immunity to T. gondii infection and its pathogenesis, its role in host cell apoptosis remains unclarified. Methods Type II GRA15 (GRA15II) cDNA was inserted into a plasmid encoding enhanced green fluorescent protein (pEGFP). Choriocarcinoma JEG-3 cells were transfected with either pEGFP or pEGFP-GRA15II and cultured for 24 h. Cell apoptosis and endoplasmic reticulum stress (ERS) responses were assessed. Inhibitors targeting inositol-requiring kinase 1α (IRE1α; 4μ8C, 100 nM) or c-Jun N-terminal kinase (JNK; SP6000125, 20 μM) were added 12 h after plasmid transfection, followed by testing the effect of GRA15II on ERS. Results When compared to pEGFP, pEGFP-GRA15II transfection facilitated cell apoptosis (P < 0.05), increased mRNA expression of caspase-3, caspase-4, 78-kDa glucose-regulated protein (GRP78), C/EBP homologous protein (CHOP) and X-box binding protein-1 (XBP1) (all P < 0.05), and promoted protein expression of cleaved caspase-3, cleaved poly(ADP-ribose) polymerase, Bax, CHOP, GRP78, phospho-JNK, and phospho-IRE1α (all P < 0.05). The 4μ8C and SP6000125 decreased apoptosis and protein expression of XBP1s, CHOP, TNF receptor-associated factor 2 (TRAF2), phosphorylated apoptosis signal-regulating kinase 1 (ASK1), cleaved caspase-3, phospho-JNK, and Bax (all P < 0.05) in pEGFP-GRA15II transfected cells. Conclusions Toxoplasma GRA15II induced ERS and subsequently caused apoptosis of choriocarcinoma JEG-3 cells.
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Affiliation(s)
- Wei Wei
- Department of Immunology, School of Basic Medicine, Anhui Medical University, Hefei, 230032, China
| | - Fangfang Zhang
- Department of Pathogen Biology and the Key Laboratory of Microbiology (Anhui), School of Basic Medicine, Anhui Medical University, Hefei, 230032, China
| | - He Chen
- Laboratory of Clinical Diagnostics, the First Hospital of Anhui Medical University, Hefei, 230032, China
| | - Yuanyuan Tang
- Department of Pathogen Biology and the Key Laboratory of Microbiology (Anhui), School of Basic Medicine, Anhui Medical University, Hefei, 230032, China
| | - Tian Xing
- Key Laboratory of Oral Diseases Research of Anhui Province, Hospital of Stomatology, Anhui Medical University, Hefei, 230032, China
| | - Qingli Luo
- Department of Pathogen Biology and the Key Laboratory of Microbiology (Anhui), School of Basic Medicine, Anhui Medical University, Hefei, 230032, China
| | - Li Yu
- Department of Pathogen Biology and the Key Laboratory of Microbiology (Anhui), School of Basic Medicine, Anhui Medical University, Hefei, 230032, China
| | - Jian Du
- Department of Pathogen Biology and the Key Laboratory of Microbiology (Anhui), School of Basic Medicine, Anhui Medical University, Hefei, 230032, China
| | - Jilong Shen
- Department of Immunology, School of Basic Medicine, Anhui Medical University, Hefei, 230032, China. .,Department of Pathogen Biology and the Key Laboratory of Microbiology (Anhui), School of Basic Medicine, Anhui Medical University, Hefei, 230032, China. .,Laboratory of Clinical Diagnostics, the First Hospital of Anhui Medical University, Hefei, 230032, China.
| | - Linjie Zhang
- Department of Immunology, School of Basic Medicine, Anhui Medical University, Hefei, 230032, China.
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Caldas LA, Attias M, de Souza W. A structural analysis of the natural egress of Toxoplasma gondii. Microbes Infect 2017; 20:57-62. [PMID: 28951315 DOI: 10.1016/j.micinf.2017.09.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/29/2017] [Accepted: 09/11/2017] [Indexed: 01/18/2023]
Abstract
Previous studies have analysed the process of Toxoplasma gondii egress with the aid of inducers, such as calcium ionophores. Although calcium transients have been successful in triggering T. gondii egress, the structural panorama of "natural" and artificial events should match. The present study approaches the natural egress of this parasite using super-resolution and electron microscopy and reveals lytic and non-lytic events of individual egress; this corroborates the use of calcium ionophore as a reliable tool to trigger parasite egress. Altogether, our data suggest that different signalling routes can converge to similar structural aspects in natural and induced egress.
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Affiliation(s)
- Lúcio Ayres Caldas
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil.
| | - Marcia Attias
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil
| | - Wanderley de Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil; Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Rio de Janeiro, Brazil
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21
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Kim JH, Lee J, Bae SJ, Kim Y, Park BJ, Choi JW, Kwon J, Cha GH, Yoo HJ, Jo EK, Bae YS, Lee YH, Yuk JM. NADPH oxidase 4 is required for the generation of macrophage migration inhibitory factor and host defense against Toxoplasma gondii infection. Sci Rep 2017; 7:6361. [PMID: 28743960 PMCID: PMC5526938 DOI: 10.1038/s41598-017-06610-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 06/14/2017] [Indexed: 12/31/2022] Open
Abstract
Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (Nox) are an important family of catalytic enzymes that generate reactive oxygen species (ROS), which mediate the regulation of diverse cellular functions. Although phagocyte Nox2/gp91phox is closely associated with the activation of host innate immune responses, the roles of Nox family protein during Toxoplasma gondii (T. gondii) infection have not been fully investigated. Here, we found that T. gondii-mediated ROS production was required for the upregulation of macrophage migration inhibitory factor (MIF) mRNA and protein levels via activation of mitogen-activated protein kinase and nuclear factor-κB signaling in macrophages. Interestingly, MIF knockdown led to a significant increase in the survival of intracellular T. gondii in bone marrow-derived macrophages (BMDMs). Moreover, Nox4 deficiency, but not Nox2/gp91phox and the cytosolic subunit p47phox, resulted in enhanced survival of the intracellular T. gondii RH strain and impaired expression of T. gondii-mediated MIF in BMDMs. Additionally, Nox4-deficient mice showed increased susceptibility to virulent RH strain infection and increased cyst burden in brain tissues and low levels of MIF expression following infection with the avirulent ME49 strain. Collectively, our findings indicate that Nox4-mediated ROS generation plays a central role in MIF production and resistance to T. gondii infection.
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Affiliation(s)
- Ji Hye Kim
- Department of Infection Biology, College of Medicine, Chungnam National University, Daejeon, South Korea.,Department of Medical Science, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Jina Lee
- Department of Infection Biology, College of Medicine, Chungnam National University, Daejeon, South Korea.,Department of Medical Science, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Su-Jin Bae
- Department of Infection Biology, College of Medicine, Chungnam National University, Daejeon, South Korea.,Department of Medical Science, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Yeeun Kim
- Department of Infection Biology, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Byung-Joon Park
- Department of Infection Biology, College of Medicine, Chungnam National University, Daejeon, South Korea.,Department of Medical Science, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Jae-Won Choi
- Department of Infection Biology, College of Medicine, Chungnam National University, Daejeon, South Korea.,Department of Medical Science, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Jaeyul Kwon
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon, South Korea.,Department of Medical Education, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Guang-Ho Cha
- Department of Infection Biology, College of Medicine, Chungnam National University, Daejeon, South Korea.,Department of Medical Science, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Heon Jong Yoo
- Department of Obstetrics and Gynecology, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Eun-Kyeong Jo
- Department of Medical Science, College of Medicine, Chungnam National University, Daejeon, South Korea.,Department of Microbiology, College of Medicine, Chungnam National University, Daejeon, South Korea
| | - Yun Soo Bae
- Department of Life Science, Ewha Womans University, Seoul, South Korea
| | - Young-Ha Lee
- Department of Infection Biology, College of Medicine, Chungnam National University, Daejeon, South Korea. .,Department of Medical Science, College of Medicine, Chungnam National University, Daejeon, South Korea.
| | - Jae-Min Yuk
- Department of Infection Biology, College of Medicine, Chungnam National University, Daejeon, South Korea. .,Department of Medical Science, College of Medicine, Chungnam National University, Daejeon, South Korea.
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22
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Liu Q, Li FC, Elsheikha HM, Sun MM, Zhu XQ. Identification of host proteins interacting with Toxoplasma gondii GRA15 (TgGRA15) by yeast two-hybrid system. Parasit Vectors 2017; 10:1. [PMID: 28049510 PMCID: PMC5209834 DOI: 10.1186/s13071-016-1943-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 12/15/2016] [Indexed: 11/10/2022] Open
Abstract
Background Toxoplasma gondii, an obligate intracellular protozoan parasite, possesses the remarkable ability to co-opt host cell machinery in order to maintain its intracellular survival. This parasite can modulate signaling pathways of its host through the secretion of polymorphic effector proteins localized in the rhoptry and dense granule organelles. One of such effectors is T. gondii type II-specific dense granule protein 15, TgGRA15, which activates NF-κB pathway. The aim of the present study was to identify the host interaction partner proteins of TgGRA15. Methods We screened a yeast two-hybrid mouse cDNA library using TgGRA15 as the bait. TgGRA15 (PRU strain, Type II) was cloned into the pGBKT7 vector and expressed in the Y2HGold yeast strain. Then, the bait protein expression was validated by western blotting analysis, followed by auto-activation and toxicity tests in comparison with control (Y2HGold yeast strain transformed with empty pGBKT7 vector). Results This screening led to the identification of mouse Luzp1 and AW209491 as host binding proteins that interact with TgGRA15. Luzp1 contains three nuclear localizing signals and is involved in regulating a subset of host non-coding RNA genes. Conclusions These findings reveal, for the first time, new host cell proteins interacting with TgGRA15. The identification of these cellular targets and the understanding of their contribution to the host-pathogen interaction may serve as the foundation for novel therapeutic and prevention strategies against T. gondii infection.
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Affiliation(s)
- Qing Liu
- College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan Province, 410128, People's Republic of China.,State Key Laboratory of Veterinary Etiological Biology, 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
| | - Fa-Cai Li
- State Key Laboratory of Veterinary Etiological Biology, 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.
| | - 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
| | - Miao-Miao Sun
- State Key Laboratory of Veterinary Etiological Biology, 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
| | - Xing-Quan Zhu
- College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan Province, 410128, People's Republic of China.,State Key Laboratory of Veterinary Etiological Biology, 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.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu Province, 225009, People's Republic of China
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23
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Zhou CX, Elsheikha HM, Zhou DH, Liu Q, Zhu XQ, Suo X. Dual Identification and Analysis of Differentially Expressed Transcripts of Porcine PK-15 Cells and Toxoplasma gondii during in vitro Infection. Front Microbiol 2016; 7:721. [PMID: 27242740 PMCID: PMC4865485 DOI: 10.3389/fmicb.2016.00721] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/29/2016] [Indexed: 12/22/2022] Open
Abstract
Toxoplasma gondii is responsible for causing toxoplasmosis, one of the most prevalent zoonotic parasitoses worldwide. The mechanisms that mediate T. gondii infection of pigs (the most common source of human infection) and renal tissues are still unknown. To identify the critical alterations that take place in the transcriptome of both porcine kidney (PK-15) cells and T. gondii following infection, infected cell samples were collected at 1, 3, 6, 9, 12, 18, and 24 h post infection and RNA-Seq data were acquired using Illumina Deep Sequencing. Differential Expression of Genes (DEGs) analysis was performed to study the concomitant gene-specific temporal patterns of induction of mRNA expression of PK-15 cells and T. gondii. High sequence coverage enabled us to thoroughly characterize T. gondii transcriptome and identify the activated molecular pathways in host cells. More than 6G clean bases/sample, including >40 million clean reads were obtained. These were aligned to the reference genome of T. gondii and wild boar (Sus scrofa). DEGs involved in metabolic activities of T. gondii showed time-dependent down-regulation. However, DEGs involved in immune or disease related pathways of PK-15 cells peaked at 6 h PI, and were highly enriched as evidenced by KEGG analysis. Protein-protein interaction analysis revealed that TGME49_120110 (PCNA), TGME49_049180 (DHFR-TS), TGME49_055320, and TGME49_002300 (ITPase) are the four hub genes with most interactions with T. gondii at the onset of infection. These results reveal altered profiles of gene expressed by PK-15 cells and T. gondii during infection and provide the groundwork for future virulence studies to uncover the mechanisms of T. gondii interaction with porcine renal tissue by functional analysis of these DEGs.
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Affiliation(s)
- Chun-Xue Zhou
- National Animal Protozoa Laboratory and College of Veterinary Medicine, China Agricultural UniversityBeijing, China; State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural SciencesLanzhou, China
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham Loughborough, UK
| | - Dong-Hui Zhou
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences Lanzhou, China
| | - Qing Liu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences Lanzhou, China
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural SciencesLanzhou, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University College of Veterinary MedicineYangzhou, China
| | - Xun Suo
- National Animal Protozoa Laboratory and College of Veterinary Medicine, China Agricultural University Beijing, China
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24
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Tonkin ML, Boulanger MJ. The shear stress of host cell invasion: exploring the role of biomolecular complexes. PLoS Pathog 2015; 11:e1004539. [PMID: 25629317 PMCID: PMC4309608 DOI: 10.1371/journal.ppat.1004539] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Michelle L. Tonkin
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Martin J. Boulanger
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
- * E-mail:
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25
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Tonin AA, Da Silva AS, Zanini D, Schmatz R, Schetinger MRC, Morsch VM, Camillo G, Vogel FSF, Stefani LM, Lopes STA. Acetylcholinesterase activity in Toxoplasma gondii tachyzoites (RH strain). ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s00580-014-2010-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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26
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Melo MB, Nguyen QP, Cordeiro C, Hassan MA, Yang N, McKell R, Rosowski EE, Julien L, Butty V, Dardé ML, Ajzenberg D, Fitzgerald K, Young LH, Saeij JPJ. Transcriptional analysis of murine macrophages infected with different Toxoplasma strains identifies novel regulation of host signaling pathways. PLoS Pathog 2013; 9:e1003779. [PMID: 24367253 PMCID: PMC3868521 DOI: 10.1371/journal.ppat.1003779] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 09/18/2013] [Indexed: 11/19/2022] Open
Abstract
Most isolates of Toxoplasma from Europe and North America fall into one of three genetically distinct clonal lineages, the type I, II and III lineages. However, in South America these strains are rarely isolated and instead a great variety of other strains are found. T. gondii strains differ widely in a number of phenotypes in mice, such as virulence, persistence, oral infectivity, migratory capacity, induction of cytokine expression and modulation of host gene expression. The outcome of toxoplasmosis in patients is also variable and we hypothesize that, besides host and environmental factors, the genotype of the parasite strain plays a major role. The molecular basis for these differences in pathogenesis, especially in strains other than the clonal lineages, remains largely unexplored. Macrophages play an essential role in the early immune response against T. gondii and are also the cell type preferentially infected in vivo. To determine if non-canonical Toxoplasma strains have unique interactions with the host cell, we infected murine macrophages with 29 different Toxoplasma strains, representing global diversity, and used RNA-sequencing to determine host and parasite transcriptomes. We identified large differences between strains in the expression level of known parasite effectors and large chromosomal structural variation in some strains. We also identified novel strain-specifically regulated host pathways, including the regulation of the type I interferon response by some atypical strains. IFNβ production by infected cells was associated with parasite killing, independent of interferon gamma activation, and dependent on endosomal Toll-like receptors in macrophages and the cytoplasmic receptor retinoic acid-inducible gene 1 (RIG-I) in fibroblasts.
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Affiliation(s)
- Mariane B. Melo
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Quynh P. Nguyen
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Cynthia Cordeiro
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
- Internal Medicine Department, School of Medicine, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Retina Service, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Musa A. Hassan
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Ninghan Yang
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Renée McKell
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Emily E. Rosowski
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Lindsay Julien
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Vincent Butty
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Marie-Laure Dardé
- Centre National de Référence Toxoplasmose/Toxoplasma Biological Resource Center, Centre Hospitalier-Universitaire Dupuytren, Limoges, France
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1094, Neuroépidémiologie Tropicale, Laboratoire de Parasitologie-Mycologie, Faculté de Médecine, Université de Limoges, Limoges, France
| | - Daniel Ajzenberg
- Centre National de Référence Toxoplasmose/Toxoplasma Biological Resource Center, Centre Hospitalier-Universitaire Dupuytren, Limoges, France
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1094, Neuroépidémiologie Tropicale, Laboratoire de Parasitologie-Mycologie, Faculté de Médecine, Université de Limoges, Limoges, France
| | - Katherine Fitzgerald
- University of Massachusetts Medical School, Division of Infectious Diseases and Immunology, Worcester, Massachusetts, United States of America
| | - Lucy H. Young
- Retina Service, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jeroen P. J. Saeij
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
- * E-mail:
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27
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Identification of lead compounds targeting the cathepsin B-like enzyme of Eimeria tenella. Antimicrob Agents Chemother 2011; 56:1190-201. [PMID: 22143531 DOI: 10.1128/aac.05528-11] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Cysteine peptidases have been implicated in the development and pathogenesis of Eimeria. We have identified a single-copy cathepsin B-like cysteine peptidase gene in the genome database of Eimeria tenella (EtCatB). Molecular modeling of the predicted protein suggested that it differs significantly from host enzymes and could be a good drug target. EtCatB was expressed and secreted as a soluble, active, glycosylated mature enzyme from Pichia pastoris. Biochemical characterization of the recombinant enzyme confirmed that it is cathepsin B-like. Screening of a focused library against the enzyme identified three inhibitors (a nitrile, a thiosemicarbazone, and an oxazolone) that can be used as leads for novel drug discovery against Eimeria. The oxazolone scaffold is a novel cysteine peptidase inhibitor; it may thus find widespread use.
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28
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Melo MB, Jensen KDC, Saeij JPJ. Toxoplasma gondii effectors are master regulators of the inflammatory response. Trends Parasitol 2011; 27:487-95. [PMID: 21893432 PMCID: PMC3200456 DOI: 10.1016/j.pt.2011.08.001] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 08/04/2011] [Accepted: 08/04/2011] [Indexed: 02/06/2023]
Abstract
Toxoplasma is a highly successful parasite that establishes a life-long chronic infection. To do this, it must carefully regulate immune activation and host cell effector mechanisms. Here we review the latest developments in our understanding of how Toxoplasma counteracts the immune response of the host, and in some cases provokes it, through the use of specific parasite effector proteins. An emerging theme from these discoveries is that Toxoplasma effectors are master regulators of the pro-inflammatory response, which elicits many of the toxoplasmacidal mechanisms of the host. We speculate that combinations of these effectors present in certain Toxoplasma strains work to maintain an optimal parasite burden in different hosts to ensure parasite transmission.
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Affiliation(s)
- Mariane B Melo
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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29
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De Pablos LM, González G, Rodrigues R, García Granados A, Parra A, Osuna A. Action of a pentacyclic triterpenoid, maslinic acid, against Toxoplasma gondii. JOURNAL OF NATURAL PRODUCTS 2010; 73:831-834. [PMID: 20441162 DOI: 10.1021/np900749b] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The action of maslinic acid (2alpha,3beta-dihydroxyolean-12-en-28-oic acid) (1), a pentacyclic derivative present in the pressed fruits of the olive (Olea europaea), has been studied against the tachyzoites of Toxoplasma gondii. The capability of tachyzoites to infect Vero cells treated with 1 was affected. The LD(50) values were 58.2 muM for the isolated tachyzoites and 236 muM for the noninfected Vero cells. Zymograms of the T. gondii proteases incubated with 1 showed a dosage-dependent inhibition of some of the proteases. The parasites treated with 1 showed gliding motility and ultrastructural alterations. The present findings suggest that protease activity of the parasite required for cell invasion is the action target for maslinic acid (1).
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Affiliation(s)
- Luis M De Pablos
- Biochemical and Molecular Parasitology Group, Biotechnology Institute, Campus de Fuentenueva, University of Granada, 18071, Granada, Spain
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30
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Pereira-Chioccola VL, Vidal JE, Su C. Toxoplasma gondii infection and cerebral toxoplasmosis in HIV-infected patients. Future Microbiol 2009; 4:1363-79. [DOI: 10.2217/fmb.09.89] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Cerebral toxoplasmosis is a major cause of morbidity and mortality among HIV-infected patients, particularly from developing countries. This article summarizes current literature on cerebral toxoplasmosis. It focuses on: Toxoplasma gondii genetic diversity and its possible relationship with disease presentation; host responses to the parasite antigens; host immunosupression in HIV and cerebral toxoplasmosis as well as different diagnostic methods; clinical and radiological features; treatment; and the direction that studies on cerebral toxoplasmosis will likely take in the future.
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Affiliation(s)
- Vera Lucia Pereira-Chioccola
- Laboratório de Parasitologia, Instituto Adolfo Lutz, Av. Dr Arnaldo, 351, 8 andar, CEP 01246-902, São Paulo, SP, Brazil
| | - José Ernesto Vidal
- Departamento de Neurologia, Instituto de Infectologia Emílio Ribas, Av. Dr Arnaldo, 165 CEP 05411-000, Sao Paulo, SP, BrazilandServiço de Extensão ao atendimento de Pacientes HIV/AIDS, Divisão de Moléstias Infecciosas e Parasitárias, Hospital das Clínicas da Faculdade de Medicina da Universidade de Sao Paulo, Rua Frei Caneca 557, Sao Paulo, SP, Brazil
| | - Chunlei Su
- Department of Microbiology F409, Walters Life Sciences Building, The University of Tennessee, 1414 W. Cumberland Ave., Knoxville, TN 37996-0845, USA
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31
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Caldas LA, de Souza W, Attias M. Microscopic analysis of calcium ionophore activated egress of Toxoplasma gondii from the host cell. Vet Parasitol 2009; 167:8-18. [PMID: 19875235 DOI: 10.1016/j.vetpar.2009.09.051] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 09/09/2009] [Accepted: 09/28/2009] [Indexed: 11/17/2022]
Abstract
Toxoplasma gondii invades and destroys nucleated cells of warm blooded hosts in a process which involves several steps: recognition, adhesion, penetration, multiplication inside a parasitophorous vacuole (PV) and egress. The last one is the least understood. Parasite egress from LLC-MK2 cells infected with the RH strain of T. gondii was artificially triggered with 4BrA23187 calcium ionophore. The combination of videomicroscopy, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) showed that egress does not result from host cell rupture due to overloading with tachyzoites. Videomicroscopy showed that upon calcium ionophore administration parasite rosettes disassemble, the contour of the parasitophorous vacuole disappears and each tachyzoite takes a separate route to the extracellular medium. FESEM and TEM showed the fragmentation of the intravacuolar network, the fragmentation of parasitophorous vacuole membrane and individual tachyzoites with extruded conoids migrating through the cytosol, tightly surrounded by remnants of parasitophorous vacuole membrane or free in the cytosol. Both videomicroscopy and FESEM showed that a single parasite can cross the host cell membrane without disrupting it, while a large number of parasites, egressing simultaneously, rupture the membrane and the cell as a whole. These data suggest that invasion and egress share less similarities than previously believed.
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Affiliation(s)
- Lucio Ayres Caldas
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil
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32
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Carvalho TL, Ribolla PEM, Curi RA, Mota LSLS. Characterization and transcriptional analysis of the promoter region of the Duffy blood group, chemokine receptor (DARC) gene in cattle. Vet Immunol Immunopathol 2009; 132:153-9. [PMID: 19559488 DOI: 10.1016/j.vetimm.2009.05.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 05/21/2009] [Accepted: 05/27/2009] [Indexed: 10/20/2022]
Abstract
The Duffy antigen is the only receptor for Plasmodium vivax, a hemoparasite of the phylum Apicomplexa and the cause of vivax malaria in humans. Resistance to this parasite in the majority of black African individuals and their descendents is due to a mutation in the gene promoter region, which blocks its transcription on erythrocytes. Regarding bovine babesiosis, it is known that taurine breeds are more susceptible to parasite infection than zebuine breeds. In order to verify whether the same human resistance occurs in bovine, the 5' flanking region of the DARC gene was isolated and characterized in Bos indicus and Bos taurus. Four single nucleotide polymorphisms were identified and genotyped (SNP1: EF_647729.1:g.91C>T; SNP2: EF_647729.1:g.405C>T; SNP3: EF_647729.1: g.433A>G and SNP4: EF_647729.1:g.588A>G), which showed significant frequency differences among 99 bovines of each species (n=198). Characterization of the isolated region revealed the presence of 6 putative haplotypes, 14 genotypes, which are formed by haplotypes, and numerous putative transcription factor binding sites. Only the thymine presence on SNPs 1 and 2, more common in B. indicus, was observed to alter some of the sites in this region. Despite this fact, analyses through real-time PCR on bovines that present the most common homozygote genotypes of each species, which contrast for all the polymorphism, revealed no difference on the DARC gene transcription. Thus, in principle, it was concluded that the polymorphisms identified would not be useful as molecular markers in an improvement program for resistance to babesiosis.
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Affiliation(s)
- T L Carvalho
- Departamento de Genética, Instituto de Biociências, UNESP, Distrito de Rubião Junior, Botucatu, SP 18618-000, Brazil
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A transient forward-targeting element for microneme-regulated secretion in Toxoplasma gondii. Biol Cell 2008; 100:253-64. [PMID: 17995454 DOI: 10.1042/bc20070076] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND INFORMATION Accurate sorting of proteins to the three types of secretory granules in Toxoplasma gondii is crucial for successful cell invasion by this obligate intracellular parasite. As in other eukaryotic systems, propeptide sequences are a common yet poorly understood feature of proteins destined for regulated secretion, which for Toxoplasma occurs through two distinct invasion organelles, rhoptries and micronemes. Microneme discharge during parasite apical attachment plays a pivotal role in cell invasion by delivering adhesive proteins for host receptor engagement. RESULTS We show here that the small micronemal proprotein MIC5 (microneme protein-5) undergoes proteolytic maturation at a site beyond the Golgi, and only the processed form of MIC5 is secreted via the micronemes. Proper cleavage of the MIC5 propeptide relies on an arginine residue in the P1' position, although P1' mutants are still cleaved to a lesser extent at an alternative site downstream of the primary site. Nonetheless, this aberrantly cleaved species still correctly traffics to the micronemes, indicating that correct cleavage is not necessary for micronemal targeting. In contrast, a deletion mutant lacking the propeptide was retained within the secretory system, principally in the ER (endoplasmic reticulum). The MIC5 propeptide also supported correct trafficking when exchanged for the M2AP propeptide, which was recently shown to also be required for micronemal trafficking of the TgMIC2 (T. gondii MIC2)-M2AP complex [Harper, Huynh, Coppens, Parussini, Moreno and Carruthers (2006) Mol. Biol. Cell 17, 4551-4563]. CONCLUSION Our results illuminate common and unique features of micronemal propeptides in their role as trafficking facilitators.
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Holec L, Gasior A, Brillowska-Dabrowska A, Kur J. Toxoplasma gondii: enzyme-linked immunosorbent assay using different fragments of recombinant microneme protein 1 (MIC1) for detection of immunoglobulin G antibodies. Exp Parasitol 2008; 119:1-6. [PMID: 18207143 DOI: 10.1016/j.exppara.2007.12.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Revised: 10/17/2007] [Accepted: 12/10/2007] [Indexed: 11/28/2022]
Abstract
Three different fragments of microneme 1 protein termed, r-MIC1ex2, r-MIC1ex34 and r-MIC1 of Toxoplasma gondii, were expressed in Escherichia coli as fusion proteins containing six histidyl residues at N- and C-terminal. After purification by metal affinity chromatography, these recombinant proteins were tested for their usefulness as antigens in an enzyme-linked immunosorbent assay for the detection of immunoglobulin G. Ninety-eight sera from patients with different stages of invasion and 24 sera from seronegative patients were examined. There was no significant difference observed in the antigenicity for human serum samples from patients with acute toxoplasmosis between three recombinant types of MIC1 antigen (96.1% for r-MIC1ex2 antigen and 100% for both r-MIC1ex34 and r-MIC1 proteins). Sera from chronic infections (with low titers of IgG antibody) showed significant lower sensitivity, especially for r-MIC1ex34 and r-MIC1 antigens (75%, 52.7% and 36.1% for r-MIC1ex2, r-MIC1ex34 and r-MIC1, respectively). These results indicate that the strongest antigenic region of the MIC1 is encoding by the second exon of mic1 gene. When r-MIC1ex2 (N-terminal fragment of protein) was combined with MAG1 (matrix antigen) and MIC3 (microneme 3 protein), the sensitivity increased to 88.9%. This result was comparable to an ELISA using a Toxoplasma lysate antigen (TLA) and two combinations of recombinant antigens: M1 (GRA1+GRA7+SAG1) and M2 (P35+SAG2+GRA6) with the sensitivity for serum samples tested 94.4%, 88.9% and 94.4%, respectively.
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Affiliation(s)
- Lucyna Holec
- Gdańsk University of Technology, Chemical Faculty, Department of Microbiology, ul. Narutowicza 11/12, 80-952 Gdańsk, Poland
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Boothroyd JC, Dubremetz JF. Kiss and spit: the dual roles of Toxoplasma rhoptries. Nat Rev Microbiol 2008; 6:79-88. [PMID: 18059289 DOI: 10.1038/nrmicro1800] [Citation(s) in RCA: 271] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Toxoplasma gondii is a single-celled, eukaryotic parasite that can only reproduce inside a host cell. Upon entry, this Apicomplexan parasite co-opts host functions for its own purposes. An unusual set of apical organelles, named rhoptries, contain some of the machinery that is used by T. gondii both for invasion and to commandeer host functions. Of particular interest are a group of injected protein kinases that are among the most variable of all the T. gondii proteins. At least one of these kinases has a major effect on host-gene expression, including the modulation of key regulators of the immune response. Here, we discuss these recent findings and use them to propose a model in which an expansion of host range is a major force that drives rhoptry-protein evolution.
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Affiliation(s)
- John C Boothroyd
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305-5124, USA.
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Lee SH, Hayes DB, Rebowski G, Tardieux I, Dominguez R. Toxofilin from Toxoplasma gondii forms a ternary complex with an antiparallel actin dimer. Proc Natl Acad Sci U S A 2007; 104:16122-7. [PMID: 17911258 PMCID: PMC2042172 DOI: 10.1073/pnas.0705794104] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many human pathogens exploit the actin cytoskeleton during infection, including Toxoplasma gondii, an apicomplexan parasite related to Plasmodium, the agent of malaria. One of the most abundantly expressed proteins of T. gondii is toxofilin, a monomeric actin-binding protein (ABP) involved in invasion. Toxofilin is found in rhoptry and presents an N-terminal signal sequence, consistent with its being secreted during invasion. We report the structure of toxofilin amino acids 69-196 in complex with the host mammalian actin. Toxofilin presents an extended conformation and interacts with an antiparallel actin dimer, in which one of the actins is related by crystal symmetry. Consistent with this observation, analytical ultracentrifugation analysis shows that toxofilin binds two actins in solution. Toxofilin folds into five consecutive helices, which form three relatively independent actin-binding sites. Helices 1 and 2 bind the symmetry-related actin molecule and cover its nucleotide-binding cleft. Helices 3-5 bind the other actin and constitute the primary actin-binding region. Helix 3 interacts in the cleft between subdomains 1 and 3, a common binding site for most ABPs. Helices 4 and 5 wrap around actin subdomain 4, and residue Gln-134 of helix 4 makes a hydrogen-bonding contact with the nucleotide in actin, both of which are unique features among ABPs. Toxofilin dramatically inhibits nucleotide exchange on two actin molecules simultaneously. This effect is linked to the formation of the antiparallel actin dimer because a construct lacking helices 1 and 2 binds only one actin and inhibits nucleotide exchange less potently.
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Affiliation(s)
- Sung Haeng Lee
- Department of Physiology, University of Pennsylvania School of Medicine, 3700 Hamilton Walk, Philadelphia, PA 19104-6085
| | - David B. Hayes
- Boston Biomedical Research Institute, 64 Grove Street, Watertown, MA 02472; and
| | - Grzegorz Rebowski
- Department of Physiology, University of Pennsylvania School of Medicine, 3700 Hamilton Walk, Philadelphia, PA 19104-6085
| | - Isabelle Tardieux
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8104, Institut Cochin, 75014 Paris, France
| | - Roberto Dominguez
- Department of Physiology, University of Pennsylvania School of Medicine, 3700 Hamilton Walk, Philadelphia, PA 19104-6085
- To whom correspondence should be addressed. E-mail:
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Bhat N, Joe A, PereiraPerrin M, Ward HD. Cryptosporidium p30, a galactose/N-acetylgalactosamine-specific lectin, mediates infection in vitro. J Biol Chem 2007; 282:34877-87. [PMID: 17905738 DOI: 10.1074/jbc.m706950200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cryptosporidium sp. cause human and animal diarrheal disease worldwide. The molecular mechanisms underlying Cryptosporidium attachment to, and invasion of, host cells are poorly understood. Previously, we described a surface-associated Gal/GalNAc-specific lectin activity in sporozoites of Cryptosporidium parvum. Here we describe p30, a 30-kDa Gal/GalNAc-specific lectin isolated from C. parvum and Cryptosporidium hominis sporozoites by Gal-affinity chromatography. p30 is encoded by a single copy gene containing a 906-bp open reading frame, the deduced amino acid sequence of which predicts a 302-amino acid, 31.8-kDa protein with a 22-amino acid N-terminal signal sequence. The p30 gene is expressed at 24-72 h after infection of intestinal epithelial cells. Antisera to recombinant p30 expressed in Escherichia coli react with an approximately 30-kDa protein in C. parvum and C. hominis. p30 is localized to the apical region of sporozoites and is predominantly intracellular in both sporozoites and intracellular stages of the parasite. p30 associates with gp900 and gp40, Gal/GalNAc-containing mucin-like glycoproteins that are also implicated in mediating infection. Native and recombinant p30 bind to Caco-2A cells in a dose-dependent, saturable, and Gal-inhibitable manner. Recombinant p30 inhibits C. parvum attachment to and infection of Caco-2A cells, whereas antisera to the recombinant protein also inhibit infection. Taken together, these findings suggest that p30 mediates C. parvum infection in vitro and raise the possibility that this protein may serve as a target for intervention.
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Affiliation(s)
- Najma Bhat
- Division of Geographic Medicine and Infectious Diseases, Tufts-New England Medical Center, Boston, Massachusetts 02111, USA
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Moran JM, Smith SS, Hager KM. Toxoplasma gondii possesses a receptor for activated C kinase ortholog. Biochem Biophys Res Commun 2007; 363:680-6. [PMID: 17900535 DOI: 10.1016/j.bbrc.2007.09.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Accepted: 09/10/2007] [Indexed: 11/17/2022]
Abstract
Receptor for activated C kinase 1 (RACK1) has been implicated in multiple protein-protein interactions including functioning as a scaffolding protein for signaling molecules. We report the cloning and cellular localization of a RACK1 ortholog (TgRACK1) in the opportunistic pathogen Toxoplasma gondii. The full-length transcript possesses a predicted ORF of 966 bp and codes for a protein of approximately 35 kDa molecular weight. Molecular analysis of TgRACK1 reveals the presence of seven WD40 repeat motifs. TgRACK1 was tagged with a FLAG epitope and stably expressed in RH parasites. FLAG-TgRACK1 localizes to the parasite cytoplasm and nucleus. Immunoprecipitation (IP) of FLAG-TgRACK1 from highly purified extracellular parasites followed by immunoblot analysis reveals an interaction between TgbetaCOP and FLAG-TgRACK1. This is the first demonstration of an interaction between a betaCOP subunit and the RACK1 protein. This result is of interest given that a signaling event precedes protein secretion and parasite invasion.
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Affiliation(s)
- Jennifer M Moran
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556-0369, USA
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Hartati S, Kusumawati A, Wuryastuti H, Widada JS. Primary structure of mature SAG1 gene of an Indonesian Toxoplasma gondii and comparison with other strains. J Vet Sci 2006; 7:263-70. [PMID: 16871021 PMCID: PMC3242126 DOI: 10.4142/jvs.2006.7.3.263] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma gondii is a persistent protozoan parasite capable of infecting almost any warm-blooded vertebrates. SAG1 (p30) is the prototypic member of a superfamily of surface antigens called SRS (SAG1-related sequence). It constitutes the most abundant and predominant antigen. In this paper the primary structure of mature SAG1 gene of an Indonesian T. gondii isolate is described and sequence comparison is made with published sequence data of 7 other strains or isolates. Sequence comparison indicated that SAG1 is highly conserved through evolution and despite parasite spreading world-wide. Sequences may be divided into two major families, independent of the strain/isolate geographic origin. Variations were mainly localized at the C-terminal half or domain 2 and some clustered in restricted areas. Sequence comparison allowed us to define the Indonesian isolate as genuine virulent RH strain. A phylogenetic tree of Toxoplasma strains/isolates was constructed based on SAG1.
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Affiliation(s)
- Sri Hartati
- Department of Internal Medicine, Gadjah Mada University, Yogyakarta, 55281, Indonesia
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40
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Gordon JL, Sibley LD. Comparative genome analysis reveals a conserved family of actin-like proteins in apicomplexan parasites. BMC Genomics 2005; 6:179. [PMID: 16343347 PMCID: PMC1334187 DOI: 10.1186/1471-2164-6-179] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Accepted: 12/12/2005] [Indexed: 01/24/2023] Open
Abstract
Background The phylum Apicomplexa is an early-branching eukaryotic lineage that contains a number of important human and animal pathogens. Their complex life cycles and unique cytoskeletal features distinguish them from other model eukaryotes. Apicomplexans rely on actin-based motility for cell invasion, yet the regulation of this system remains largely unknown. Consequently, we focused our efforts on identifying actin-related proteins in the recently completed genomes of Toxoplasma gondii, Plasmodium spp., Cryptosporidium spp., and Theileria spp. Results Comparative genomic and phylogenetic studies of apicomplexan genomes reveals that most contain only a single conventional actin and yet they each have 8–10 additional actin-related proteins. Among these are a highly conserved Arp1 protein (likely part of a conserved dynactin complex), and Arp4 and Arp6 homologues (subunits of the chromatin-remodeling machinery). In contrast, apicomplexans lack canonical Arp2 or Arp3 proteins, suggesting they lost the Arp2/3 actin polymerization complex on their evolutionary path towards intracellular parasitism. Seven of these actin-like proteins (ALPs) are novel to apicomplexans. They show no phylogenetic associations to the known Arp groups and likely serve functions specific to this important group of intracellular parasites. Conclusion The large diversity of actin-like proteins in apicomplexans suggests that the actin protein family has diverged to fulfill various roles in the unique biology of intracellular parasites. Conserved Arps likely participate in vesicular transport and gene expression, while apicomplexan-specific ALPs may control unique biological traits such as actin-based gliding motility.
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Affiliation(s)
- Jennifer L Gordon
- Department of Molecular Microbiology, Washington University, School of Medicine, 660 S. Euclid Ave. St, Louis, MO, USA
| | - L David Sibley
- Department of Molecular Microbiology, Washington University, School of Medicine, 660 S. Euclid Ave. St, Louis, MO, USA
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Umemiya R, Fukuda M, Fujisaki K, Matsui T. ELECTRON MICROSCOPIC OBSERVATION OF THE INVASION PROCESS OF CRYPTOSPORIDIUM PARVUM IN SEVERE COMBINED IMMUNODEFICIENCY MICE. J Parasitol 2005; 91:1034-9. [PMID: 16419745 DOI: 10.1645/ge-508r.1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Cryptosporidium parvum mainly invades the intestinal epithelium and causes watery diarrhea in humans and calves. However, the invasion process has not yet been clarified. In the present study, the invasion process of C. parvum in severe combined immunodeficiency (SCID) mice was examined. Infected mice were necropsied; the ilea were double-fixed routinely and observed by scanning and transmission electron microscopy. In addition, the microvillus membrane was observed by ruthenium red staining. Scanning electron micrographs showed elongation of the microvilli at the periphery of the parasite. The microvilli were shown to be along the surface of the parasite in higher magnification. Transmission electron microscopy confirmed that the invading parasites were located among microvilli. Parasites existed in the parasitophorous vacuole formed by the microvillus membrane. The parasite pellicle attached to the host cell membrane at the bottom of the parasite, and then the pellicle and host cell membrane became unclear. Subsequently, the pellicle became complicated and formed a feeder organelle. In addition, invasion of the parasite was not observed in either a microvillus or the cytoplasm of the host cell. Therefore, C. parvum invades among microvilli, is covered with membranes derived from numerous microvilli, and develops within the host cell.
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Affiliation(s)
- Rika Umemiya
- Health Sciences, Graduate School of Health Sciences, Kyorin University, Hachioji-shi, Tokyo, Japan.
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42
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Frevert U, Engelmann S, Zougbédé S, Stange J, Ng B, Matuschewski K, Liebes L, Yee H. Intravital observation of Plasmodium berghei sporozoite infection of the liver. PLoS Biol 2005; 3:e192. [PMID: 15901208 PMCID: PMC1135295 DOI: 10.1371/journal.pbio.0030192] [Citation(s) in RCA: 243] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2004] [Accepted: 03/30/2005] [Indexed: 01/08/2023] Open
Abstract
Plasmodium sporozoite invasion of liver cells has been an extremely elusive event to study. In the prevailing model, sporozoites enter the liver by passing through Kupffer cells, but this model was based solely on incidental observations in fixed specimens and on biochemical and physiological data. To obtain direct information on the dynamics of sporozoite infection of the liver, we infected live mice with red or green fluorescent Plasmodium berghei sporozoites and monitored their behavior using intravital microscopy. Digital recordings show that sporozoites entering a liver lobule abruptly adhere to the sinusoidal cell layer, suggesting a high-affinity interaction. They glide along the sinusoid, with or against the bloodstream, to a Kupffer cell, and, by slowly pushing through a constriction, traverse across the space of Disse. Once inside the liver parenchyma, sporozoites move rapidly for many minutes, traversing several hepatocytes, until ultimately settling within a final one. Migration damage to hepatocytes was confirmed in liver sections, revealing clusters of necrotic hepatocytes adjacent to structurally intact, sporozoite-infected hepatocytes, and by elevated serum alanine aminotransferase activity. In summary, malaria sporozoites bind tightly to the sinusoidal cell layer, cross Kupffer cells, and leave behind a trail of dead hepatocytes when migrating to their final destination in the liver.
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Affiliation(s)
- Ute Frevert
- Department of Medical and Molecular Parasitology, New York University School of Medicine, New York, New York, USA.
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Magno RC, Straker LC, de Souza W, Attias M. Interrelations between the parasitophorous vacuole of Toxoplasma gondii and host cell organelles. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2005; 11:166-174. [PMID: 15817146 DOI: 10.1017/s1431927605050129] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2003] [Indexed: 05/24/2023]
Abstract
Toxoplasma gondii, the causative agent of toxoplasmosis, is capable of actively penetrating and multiplying in any nucleated cell of warm-blooded animals. Its survival strategies include escape from fusion of the parasitophorous vacuole with host cell lysosomes and rearrangement of host cell organelles in relation to the parasitophorous vacuole. In this article we report the rearrangement of host cell organelles and elements of the cytoskeleton of LLCMK2 cells, a lineage derived from green monkey kidney epithelial cells, in response to infection by T. gondii tachyzoites. Transmission electron microscopy made on flat embedded monolayers cut horizontally to the apical side of the cells or field emission scanning electron microscopy of monolayers scraped with scotch tape before sputtering showed that association of mitochondria to the vacuole is much less frequent than previously described. On the other hand, all parasitophorous vacuoles were surrounded by elements of the endoplasmic reticulum. These data were complemented by observations by laser scanning microscopy using fluorescent probes from mitochondria and endoplasmic reticulum and reinforced by three-dimensional reconstruction from serial sections observed by transmission electron microscopy and labeling of mitochondria and endoplasmic reticulum by fluorescent probes.
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Affiliation(s)
- Rodrigo Cardoso Magno
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCS-Bloco G, CEP 21949-900-Rio de Janeiro-RJ, Brazil
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Nandan D, Reiner NE. Leishmania donovani engages in regulatory interference by targeting macrophage protein tyrosine phosphatase SHP-1. Clin Immunol 2005; 114:266-77. [PMID: 15721837 DOI: 10.1016/j.clim.2004.07.017] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Accepted: 07/22/2004] [Indexed: 11/21/2022]
Abstract
Protozoan parasites of the genus leishmania are obligate intracellular parasites of monocytes and macrophages. These pathogens have evolved to invade the mammalian immune system and typically survive for long periods of time. Leishmania have developed a variety of remarkable strategies to prevent their elimination by both innate and acquired immune effector mechanisms. One particular strategy of interest involves manipulation of host cell regulatory pathways so as to prevent macrophage activation required for efficient microbicidal activity. These interference mechanisms are the main focus of this review. Several lines of evidence have been developed to show that the Src homology-2 domain containing tyrosine phosphatase-1 (SHP-1) becomes activated in leishmania-infected cells and that this contributes to disease pathogenesis. Recent studies aimed at understanding the mechanism responsible for the change in activation state of SHP-1 led to the identification of leishmania EF-1alpha as an SHP-1 binding protein and SHP-1 activator. This was a surprising finding given that this ubiquitous and highly conserved protein plays an essential role in protein translation in both prokaryotic and eukaryotic cells. The role of leishmania EF-1alpha as an SHP-1 activator and its contribution to pathogenesis are reviewed with particular attention to the properties that distinguish it from host EF-1alpha.
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Affiliation(s)
- Devki Nandan
- Division of Infectious Diseases, Department of Medicine, Vancouver Coastal Health Research Institute (VCHRI), The University of British Columbia, Room 452D, 2733 Heather Street, Vancouver, BC, Canada, V5Z 3J5.
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Labbé M, de Venevelles P, Girard-Misguich F, Bourdieu C, Guillaume A, Péry P. Eimeria tenella microneme protein EtMIC3: identification, localisation and role in host cell infection. Mol Biochem Parasitol 2005; 140:43-53. [PMID: 15694485 DOI: 10.1016/j.molbiopara.2004.12.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2004] [Revised: 11/26/2004] [Accepted: 12/08/2004] [Indexed: 11/26/2022]
Abstract
The gene coding for Eimeria tenella protein EtMIC3 was cloned by screening a sporozoite cDNA library with two independent monoclonal antibodies raised against the oocyst stage. The deduced sequence of EtMIC3 is 988 amino acids long. The protein presents seven repeats in tandem, with four highly conserved internal repeats and three more divergent external repeats. Each repeat is characterised by a tyrosine kinase phosphorylation site, WRCY, and a reminiscent motif of the thrombospondin1 (TSP1)-type I domain, CXXXCG. The protein EtMIC3 is localised at the apex of free parasite stages. It is not detected in the early intracellular parasite stage but is synthesised in mature schizonts. Secretion of the protein is induced when sporozoites are incubated in complete medium at 41 degrees C. Strangely enough, the two independent mAb that allow cloning of EtMIC3 interfere with parasitic growth in different ways. One is able to inhibit parasite invasion whereas the other inhibits development. Expression and localisation of the protein EtMIC3 are consistent with a protein involved in the invasion process as is expected for a microneme protein.
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Affiliation(s)
- M Labbé
- Laboratoire de Virologie et Immunologie Moléculaires INRA, 78352 Jouy-en-Josas, France.
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Abstract
Parasitic protozoa are surrounded by membrane structures that have a different lipid and protein composition relative to membranes of the host. The parasite membranes are essential structurally and also for parasite specific processes, like host cell invasion, nutrient acquisition or protection against the host immune system. Furthermore, intracellular parasites can modulate membranes of their host, and trafficking of membrane components occurs between host membranes and those of the intracellular parasite. Phospholipids are major membrane components and, although many parasites scavenge these phospholipids from their host, most parasites also synthesise phospholipids de novo, or modify a large part of the scavenged phospholipids. It was recently shown that some parasites like Plasmodium have unique phospholipid metabolic pathways. This review will focus on new developments in research on phospholipid metabolism of parasitic protozoa in relation to parasite-specific membrane structures and function, as well as on several targets for interference with the parasite phospholipid metabolism with a view to developing new anti-parasitic drugs.
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Affiliation(s)
- Henri J Vial
- Dynamique Moléculaire des Interactions Membranaires, CNRS UMR 5539, cc107, Université Montpellier II, Place Eugène Bataillon, 34095 Montpellier, France.
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Butcher BA, Denkers EY. Mechanism of entry determines the ability of Toxoplasma gondii to inhibit macrophage proinflammatory cytokine production. Infect Immun 2002; 70:5216-24. [PMID: 12183573 PMCID: PMC128277 DOI: 10.1128/iai.70.9.5216-5224.2002] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Macrophages (Mphi) infected with tachyzoites of the opportunistic protozoan Toxoplasma gondii are blocked in production of the proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha) and interleukin-12 (IL-12) in response to lipopolysaccharide (LPS) triggering, and this is associated with parasite-induced inhibition of NFkappaB translocation. Here, we demonstrate a requirement for active invasion in the ability of the parasite to mediate suppression. Neither soluble tachyzoite antigen nor secreted products were suppressive, and heat-inactivated, antibody-coated tachyzoites, which efficiently entered the cell through receptor-mediated uptake, failed to inhibit LPS responses. Cytochalasin D, a drug blocking tachyzoite invasion of, but not adherence to, Mphi, severely curtailed Toxoplasma-induced suppression. In addition, parasite-induced nonresponsiveness, as measured by TNF-alpha production, was reversed by treating infected cells with the toxoplasmastatic drugs pyrimethamine and 6-thioxanthine prior to LPS stimulation. A divergence in IL-12 and TNF-alpha responses was found during extended incubation of tachyzoites and Mphi in that 24 h of incubation of infected Mphi resulted in IL-12, but not TNF-alpha, secretion, and production of the latter cytokine remained suppressed when these cells were subjected to LPS triggering. Our results demonstrate that active invasion and survival of the parasite within the parasitophorous vacuole are required to induce and maintain Mphi cytokine-specific nonresponsiveness to LPS. They also show that the effects of Toxoplasma on IL-12 and TNF-alpha production are nonidentical, with the parasite exerting a longer-lasting suppression of the latter.
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Affiliation(s)
- Barbara A Butcher
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853-6401, USA
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Delorme V, Garcia A, Cayla X, Tardieux I. A role for Toxoplasma gondii type 1 ser/thr protein phosphatase in host cell invasion. Microbes Infect 2002; 4:271-8. [PMID: 11909736 DOI: 10.1016/s1286-4579(02)01538-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Host cell invasion by Toxoplasma gondii tachyzoites relies on many coordinated processes. The tachyzoite participates in invasion by providing an actomyosin-dependent force driving it into the nascent parasitophorous vacuole as well as by releasing molecules which contribute to the vacuole membrane. Exposure to type 1/2A protein phosphatase inhibitors, okadaic acid (OA) or tautomycin significantly impairs tachyzoite invasiveness. Furthermore, the tachyzoite extract contains a biochemically active type 1, but not a type 2A, serine-threonine protein phosphatase, which is immunologically related to eukaryotic phosphatase type 1 catalytic subunit. When tachyzoite extracts are incubated with a monoclonal antibody reactive to human type 1 catalytic subunit, other T. gondii molecules are coprecipitated among which one competes with the inhibitory toxin OA. Finally, in vitro phosphate labelling assays indicate that the biochemically characterized PP1 activity controls the phosphorylation of several proteins. Taken together, these data strongly suggest that the type 1 phosphatase activity detected in invasive tachyzoites is implicated in the control of the host cell invasion process.
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Affiliation(s)
- Violaine Delorme
- Institut Cochin de génétique moléculaire, CNRS-UPR 415, 22, rue Méchain, 75014 Paris, France
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Velge-Roussel F, Dimier-Poisson I, Buzoni-Gatel D, Bout D. Anti-SAG1 peptide antibodies inhibit the penetration of Toxoplasma gondii tachyzoites into enterocyte cell lines. Parasitology 2001; 123:225-33. [PMID: 11578086 DOI: 10.1017/s0031182001008460] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The initial attachment of Toxoplasma tachyzoites to the target host cell is an important event in the life-cycle of the parasite and a critical stage in infection. Previous studies have shown that polyclonal antibodies directed against the major surface antigen of Toxoplasma gondii (SAG1) inhibit the infection of enterocyte cell lines. Here, we demonstrate that antibodies raised against a central peptide (V41T) of SAG1 and the SAGI protein itself are able to inhibit the infection of various cell lines by the tachyzoites. Antibodies directed against SAG1 peptides were used to define a site on the SAGI antigen that interacts with the host cell. The epitope carried by V41T was identified on the tachyzoite surface by immunofluorescence. The peptide sequence seems to be conserved in all the members of the SAGI Related Sequence family (SRS). Using undifferentiated and differentiated Caco-2 cells, we found that tachyzoites enter preferentially via the basolateral side of the cell. These findings highlight the role of the SRS family members in the mediation of host cell invasion.
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Affiliation(s)
- F Velge-Roussel
- UMR UNIVERSITE-INRA d'Immunologie Parasitaire, UFR des Sciences Pharmaceutiques, Tours, France.
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Jacquet A, Coulon L, De Nève J, Daminet V, Haumont M, Garcia L, Bollen A, Jurado M, Biemans R. The surface antigen SAG3 mediates the attachment of Toxoplasma gondii to cell-surface proteoglycans. Mol Biochem Parasitol 2001; 116:35-44. [PMID: 11463464 DOI: 10.1016/s0166-6851(01)00297-3] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The attachment of Toxoplasma gondii to target cells is mediated by recognition of cellular heparan sulfate proteoglycans (HSPGs). The present study was performed to determine whether SAG1 and SAG3, two of the parasite surface antigens anchored to the membrane via glycosylphosphatidylinositol groups (GPIs), are involved in the tachyzoite binding to proteoglycans. The use of recombinant soluble forms of these proteins allowed us to demonstrate that SAG3, but not SAG1, interacts specifically with cellular HSPGs. Indeed, soluble recombinant SAG3 protein (recSAG3) was found to bind to immobilized heparin, whereas recSAG1 did not interact with this glycoaminoglycan. The specific adherence of recSAG3 to CHO cells was inhibited by soluble glycoconjugates, of which heparin, fucoidan and dextran sulfate were the most effective. Moreover, binding of recSAG3 to two HSPGs-deficient cell mutants was reduced by up to 80%. Proteoglycan sulfation was critical for SAG3 adherence to HSPGs as incubation of cells in the presence of sodium chlorate drastically reduced the recSAG3 binding. Finally, preincubation of CHO cells with recSAG3 blocked the adsorption of radiolabelled Toxoplasma tachyzoites. Taken together, these results indicate that SAG3 is a first glycoaminoglycan-binding protein associated with Toxoplasma, and SAG3-HSPGs interactions are involved in the parasite attachment to target cells.
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Affiliation(s)
- A Jacquet
- Department of Applied Genetics, Institut de Biologie et de Médicine Moléculaires, Université Libre de Bruxelles, Rue des Professeurs Jeener et Brachet 12, B-6041 Gosselies, Belgium.
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