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Tang L, Sabi MM, Fu M, Guan J, Wang Y, Xia T, Zheng K, Qu H, Han B. Host cell manipulation by microsporidia secreted effectors: Insights into intracellular pathogenesis. J Eukaryot Microbiol 2024:e13029. [PMID: 39030770 DOI: 10.1111/jeu.13029] [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: 03/06/2024] [Revised: 03/29/2024] [Accepted: 03/29/2024] [Indexed: 07/22/2024]
Abstract
Microsporidia are prolific producers of effector molecules, encompassing both proteins and nonproteinaceous effectors, such as toxins, small RNAs, and small peptides. These secreted effectors play a pivotal role in the pathogenicity of microsporidia, enabling them to subvert the host's innate immunity and co-opt metabolic pathways to fuel their own growth and proliferation. However, the genomes of microsporidia, despite falling within the size range of bacteria, exhibit significant reductions in both structural and physiological features, thereby affecting the repertoire of secretory effectors to varying extents. This review focuses on recent advances in understanding how microsporidia modulate host cells through the secretion of effectors, highlighting current challenges and proposed solutions in deciphering the complexities of microsporidial secretory effectors.
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Affiliation(s)
- Liyuan Tang
- Department of Pathogenic Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Ji'nan, Shandong, China
| | - Musa Makongoro Sabi
- Department of Pathogenic Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Ji'nan, Shandong, China
| | - Ming Fu
- Department of Pathogenic Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Ji'nan, Shandong, China
| | - Jingyu Guan
- Department of Pathogenic Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Ji'nan, Shandong, China
| | - Yongliang Wang
- Department of Pathogenic Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Ji'nan, Shandong, China
| | - Tian Xia
- Department of Pathogenic Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Ji'nan, Shandong, China
| | - Kai Zheng
- Department of Pathogenic Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Ji'nan, Shandong, China
| | - Hongnan Qu
- Department of Pathogenic Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Ji'nan, Shandong, China
- Shenzhen Research Institute, Shandong University, Shenzhen, Guangdong, China
| | - Bing Han
- Department of Pathogenic Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Ji'nan, Shandong, China
- Shenzhen Research Institute, Shandong University, Shenzhen, Guangdong, China
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2
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Yeh YT, Del Álamo JC, Caffrey CR. Biomechanics of parasite migration within hosts. Trends Parasitol 2024; 40:164-175. [PMID: 38172015 DOI: 10.1016/j.pt.2023.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/30/2023] [Accepted: 12/01/2023] [Indexed: 01/05/2024]
Abstract
The dissemination of protozoan and metazoan parasites through host tissues is hindered by cellular barriers, dense extracellular matrices, and fluid forces in the bloodstream. To overcome these diverse biophysical impediments, parasites implement versatile migratory strategies. Parasite-exerted mechanical forces and upregulation of the host's cellular contractile machinery are the motors for these strategies, and these are comparably better characterized for protozoa than for helminths. Using the examples of the protozoans, Toxoplasma gondii and Plasmodium, and the metazoan, Schistosoma mansoni, we highlight how quantitative tools such as traction force and reflection interference contrast microscopies have improved our understanding of how parasites alter host mechanobiology to promote their migration.
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Affiliation(s)
- Yi-Ting Yeh
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA.
| | - Juan C Del Álamo
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington, Seattle, WA 98109, USA; Division of Cardiology, University of Washington, Seattle, WA 98109, USA; Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 93093, USA
| | - Conor R Caffrey
- Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, 9500 Gilman Drive, MC0657, University of California San Diego, La Jolla, CA 92093, USA
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3
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Cudjoe O, Afful R, Hagan TA. Toxoplasma-host endoplasmic reticulum interaction: How T. gondii activates unfolded protein response and modulates immune response. CURRENT RESEARCH IN MICROBIAL SCIENCES 2024; 6:100223. [PMID: 38352129 PMCID: PMC10861954 DOI: 10.1016/j.crmicr.2024.100223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024] Open
Abstract
Toxoplasma gondii is a neurotropic single-celled zoonotic parasite that can infect human beings and animals. Infection with T. gondii is usually asymptomatic in immune-competent individual, however, it can cause symptomatic and life-threatening conditions in immunocompromised individuals and in developing foetuses. Although the mechanisms that allow T. gondii to persist in host cells are poorly understood, studies in animal models have greatly improved our understanding of Toxoplasma-host cell interaction and how this interaction modulates parasite proliferation and development, host immune response and virulence of the parasite. T. gondii is capable of recruiting the host endoplasmic reticulum (ER), suggesting it may influence the host ER function. Herein, we provide an overview of T. gondii infection and the role of host ER during stressed conditions. Furthermore, we highlight studies that explore T. gondii's interaction with the host ER. We delve into how this interaction activates the unfolded protein response (UPR) and ER stress-mediated apoptosis. Additionally, we examine how T. gondii exploits these pathways to its advantage.
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Affiliation(s)
- Obed Cudjoe
- Department of Medical Laboratory Science, Klintaps College of Health and Allied Sciences, DTD TDC Plot 30A, Klagon, Tema, Ghana
- Department of Microbiology and Immunology, School of Medical Sciences, College of Health and Allied Sciences, University of Cape Coast, Ghana
| | - Roger Afful
- Department of Medical Laboratory Science, Klintaps College of Health and Allied Sciences, DTD TDC Plot 30A, Klagon, Tema, Ghana
| | - Tonny Abraham Hagan
- Department of Biomedical Engineering, School of Life Science and Technology, University of Electronic Science and Technology of China, China
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4
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Aguilera MO, Delgui LR, Reggiori F, Romano PS, Colombo MI. Autophagy as an innate immunity response against pathogens: a Tango dance. FEBS Lett 2024; 598:140-166. [PMID: 38101809 DOI: 10.1002/1873-3468.14788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/18/2023] [Accepted: 10/27/2023] [Indexed: 12/17/2023]
Abstract
Intracellular infections as well as changes in the cell nutritional environment are main events that trigger cellular stress responses. One crucial cell response to stress conditions is autophagy. During the last 30 years, several scenarios involving autophagy induction or inhibition over the course of an intracellular invasion by pathogens have been uncovered. In this review, we will present how this knowledge was gained by studying different microorganisms. We intend to discuss how the cell, via autophagy, tries to repel these attacks with the objective of destroying the intruder, but also how some pathogens have developed strategies to subvert this. These two fates can be compared with a Tango, a dance originated in Buenos Aires, Argentina, in which the partner dancers are in close connection. One of them is the leader, embracing and involving the partner, but the follower may respond escaping from the leader. This joint dance is indeed highly synchronized and controlled, perfectly reflecting the interaction between autophagy and microorganism.
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Affiliation(s)
- Milton O Aguilera
- Laboratorio de Mecanismos Moleculares Implicados en el Tráfico Vesicular y la Autofagia-Instituto de Histología y Embriología (IHEM), Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina
- Facultad de Odontología, Microbiología, Parasitología e Inmunología, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Laura R Delgui
- Instituto de Histología y Embriología de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Centro Universitario M5502JMA, Universidad Nacional de Cuyo (UNCuyo), Mendoza, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo (UNCuyo), Mendoza, Argentina
| | - Fulvio Reggiori
- Department of Biomedicine, Aarhus University, Denmark
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Denmark
| | - Patricia S Romano
- Laboratorio de Biología de Trypanosoma cruzi y la célula hospedadora - Instituto de Histología y Embriología de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Centro Universitario M5502JMA, Universidad Nacional de Cuyo (UNCuyo), Mendoza, Argentina
- Facultad de Ciencias Médicas, Centro Universitario M5502JMA, Universidad Nacional de Cuyo (UNCuyo), Mendoza, Argentina
| | - María I Colombo
- Laboratorio de Mecanismos Moleculares Implicados en el Tráfico Vesicular y la Autofagia-Instituto de Histología y Embriología (IHEM), Universidad Nacional de Cuyo, CONICET, Mendoza, Argentina
- Facultad de Ciencias Médicas, Centro Universitario M5502JMA, Universidad Nacional de Cuyo (UNCuyo), Mendoza, Argentina
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5
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Martinez M, Mageswaran SK, Guérin A, Chen WD, Thompson CP, Chavin S, Soldati-Favre D, Striepen B, Chang YW. Origin and arrangement of actin filaments for gliding motility in apicomplexan parasites revealed by cryo-electron tomography. Nat Commun 2023; 14:4800. [PMID: 37558667 PMCID: PMC10412601 DOI: 10.1038/s41467-023-40520-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 07/26/2023] [Indexed: 08/11/2023] Open
Abstract
The phylum Apicomplexa comprises important eukaryotic parasites that invade host tissues and cells using a unique mechanism of gliding motility. Gliding is powered by actomyosin motors that translocate host-attached surface adhesins along the parasite cell body. Actin filaments (F-actin) generated by Formin1 play a central role in this critical parasitic activity. However, their subcellular origin, path and ultrastructural arrangement are poorly understood. Here we used cryo-electron tomography to image motile Cryptosporidium parvum sporozoites and reveal the cellular architecture of F-actin at nanometer-scale resolution. We demonstrate that F-actin nucleates at the apically positioned preconoidal rings and is channeled into the pellicular space between the parasite plasma membrane and the inner membrane complex in a conoid extrusion-dependent manner. Within the pellicular space, filaments on the inner membrane complex surface appear to guide the apico-basal flux of F-actin. F-actin concordantly accumulates at the basal end of the parasite. Finally, analyzing a Formin1-depleted Toxoplasma gondii mutant pinpoints the upper preconoidal ring as the conserved nucleation hub for F-actin in Cryptosporidium and Toxoplasma. Together, we provide an ultrastructural model for the life cycle of F-actin for apicomplexan gliding motility.
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Affiliation(s)
- Matthew Martinez
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Shrawan Kumar Mageswaran
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Institute of Structural Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Amandine Guérin
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - William David Chen
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Cameron Parker Thompson
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Sabine Chavin
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, USA
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Boris Striepen
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yi-Wei Chang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Institute of Structural Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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6
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Developing Anti-Babesia bovis Blood Stage Vaccines: A New Perspective Regarding Synthetic Vaccines. Int J Mol Sci 2023; 24:ijms24065219. [PMID: 36982294 PMCID: PMC10049154 DOI: 10.3390/ijms24065219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 12/22/2022] [Accepted: 01/13/2023] [Indexed: 03/12/2023] Open
Abstract
Bovine babesiosis is caused by the Apicomplexa parasites from the genus Babesia. It is one of the most important tick-borne veterinary diseases worldwide; Babesia bovis being the species associated with the most severe clinical signs of the disease and causing the greatest economic losses. Many limitations related to chemoprophylaxis and the acaricides control of transmitting vectors have led to the adoption of live attenuated vaccine immunisation against B. bovis as an alternative control strategy. However, whilst this strategy has been effective, several drawbacks related to its production have prompted research into alternative methodologies for producing vaccines. Classical approaches for developing anti-B. bovis vaccines are thus discussed in this review and are compared to a recent functional approach to highlight the latter’s advantages when designing an effective synthetic vaccine targeting this parasite.
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7
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Romano PS, Akematsu T, Besteiro S, Bindschedler A, Carruthers VB, Chahine Z, Coppens I, Descoteaux A, Alberto Duque TL, He CY, Heussler V, Le Roch KG, Li FJ, de Menezes JPB, Menna-Barreto RFS, Mottram JC, Schmuckli-Maurer J, Turk B, Tavares Veras PS, Salassa BN, Vanrell MC. Autophagy in protists and their hosts: When, how and why? AUTOPHAGY REPORTS 2023; 2:2149211. [PMID: 37064813 PMCID: PMC10104450 DOI: 10.1080/27694127.2022.2149211] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 11/15/2022] [Indexed: 03/12/2023]
Abstract
Pathogenic protists are a group of organisms responsible for causing a variety of human diseases including malaria, sleeping sickness, Chagas disease, leishmaniasis, and toxoplasmosis, among others. These diseases, which affect more than one billion people globally, mainly the poorest populations, are characterized by severe chronic stages and the lack of effective antiparasitic treatment. Parasitic protists display complex life-cycles and go through different cellular transformations in order to adapt to the different hosts they live in. Autophagy, a highly conserved cellular degradation process, has emerged as a key mechanism required for these differentiation processes, as well as other functions that are crucial to parasite fitness. In contrast to yeasts and mammals, protist autophagy is characterized by a modest number of conserved autophagy-related proteins (ATGs) that, even though, can drive the autophagosome formation and degradation. In addition, during their intracellular cycle, the interaction of these pathogens with the host autophagy system plays a crucial role resulting in a beneficial or harmful effect that is important for the outcome of the infection. In this review, we summarize the current state of knowledge on autophagy and other related mechanisms in pathogenic protists and their hosts. We sought to emphasize when, how, and why this process takes place, and the effects it may have on the parasitic cycle. A better understanding of the significance of autophagy for the protist life-cycle will potentially be helpful to design novel anti-parasitic strategies.
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Affiliation(s)
- Patricia Silvia Romano
- Laboratorio de Biología de Trypanosoma cruzi y de la célula hospedadora. Instituto de Histología y Embriología de Mendoza. Universidad Nacional de Cuyo. (IHEM-CONICET-UNCUYO). Facultad de Ciencias Médicas. Universidad Nacional de Cuyo. Av. Libertador 80 (5500), Mendoza, Argentina
| | - Takahiko Akematsu
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan
| | | | | | - Vern B Carruthers
- Department of Microbiology and Immunology, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - Zeinab Chahine
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
| | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology. Department of Molecular Microbiology and Immunology. Johns Hopkins Malaria Research Institute. Johns Hopkins University Bloomberg School of Public Health. Baltimore 21205, MD, USA
| | - Albert Descoteaux
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique, Laval, QC
| | - Thabata Lopes Alberto Duque
- Autophagy Inflammation and Metabolism Center, University of New Mexico Health Sciences Center, Albuquerque, NM, USA; Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Cynthia Y He
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Volker Heussler
- Institute of Cell Biology.University of Bern. Baltzerstr. 4 3012 Bern
| | - Karine G Le Roch
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
| | - Feng-Jun Li
- Department of Biological Sciences, National University of Singapore, Singapore
| | | | | | - Jeremy C Mottram
- York Biomedical Research Institute, Department of Biology, University of York, York, UK
| | | | - Boris Turk
- Department of Biochemistry and Molecular and Structural Biology, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Patricia Sampaio Tavares Veras
- Laboratory of Host-Parasite Interaction and Epidemiology, Gonçalo Moniz Institute, Fiocruz-Bahia
- National Institute of Science and Technology of Tropical Diseases - National Council for Scientific Research and Development (CNPq)
| | - Betiana Nebai Salassa
- Laboratorio de Biología de Trypanosoma cruzi y de la célula hospedadora. Instituto de Histología y Embriología de Mendoza. Universidad Nacional de Cuyo. (IHEM-CONICET-UNCUYO). Facultad de Ciencias Médicas. Universidad Nacional de Cuyo. Av. Libertador 80 (5500), Mendoza, Argentina
| | - María Cristina Vanrell
- Laboratorio de Biología de Trypanosoma cruzi y de la célula hospedadora. Instituto de Histología y Embriología de Mendoza. Universidad Nacional de Cuyo. (IHEM-CONICET-UNCUYO). Facultad de Ciencias Médicas. Universidad Nacional de Cuyo. Av. Libertador 80 (5500), Mendoza, Argentina
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8
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Invasion of Toxoplasma gondii bradyzoites: Molecular dissection of the moving junction proteins and effective vaccination targets. Proc Natl Acad Sci U S A 2023; 120:e2219533120. [PMID: 36693095 PMCID: PMC9945962 DOI: 10.1073/pnas.2219533120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Toxoplasmosis is a neglected parasitic disease necessitating public health control. Host cell invasion by Toxoplasma occurs at different stages of the parasite's life cycle and is crucial for survival and establishment of infection. In tachyzoites, which are responsible for acute toxoplasmosis, invasion involves the formation of a molecular bridge between the parasite and host cell membranes, referred to as the moving junction (MJ). The MJ is shaped by the assembly of AMA1 and RON2, as part of a complex involving additional RONs. While this essential process is well characterized in tachyzoites, the invasion process remains unexplored in bradyzoites, which form cysts and are responsible for chronic toxoplasmosis and contribute to the dissemination of the parasite between hosts. Here, we show that bradyzoites invade host cells in an MJ-dependent fashion but differ in protein composition from the tachyzoite MJ, relying instead on the paralogs AMA2 and AMA4. Functional characterization of AMA4 reveals its key role for cysts burden during the onset of chronic infection, while being dispensable for the acute phase. Immunizations with AMA1 and AMA4, alone or in complex with their rhoptry neck respective partners RON2 and RON2L1, showed that the AMA1-RON2 pair induces strong protection against acute and chronic infection, while the AMA4-RON2L1 complex targets more selectively the chronic form. Our study provides important insights into the molecular players of bradyzoite invasion and indicates that invasion of cyst-forming bradyzoites contributes to cyst burden. Furthermore, we validate AMA-RON complexes as potential vaccine candidates to protect against toxoplasmosis.
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9
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Zhang J, Fan F, Zhang L, Shen B. Nuclear Factor AP2X-4 Governs the Expression of Cell Cycle- and Life Stage-Regulated Genes and is Critical for Toxoplasma Growth. Microbiol Spectr 2022; 10:e0012022. [PMID: 35735977 PMCID: PMC9430314 DOI: 10.1128/spectrum.00120-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 06/06/2022] [Indexed: 11/21/2022] Open
Abstract
Toxoplasma gondii is a ubiquitous pathogen infecting one third of the world's population and diverse animals. It has a complex life cycle alternating among different developmental stages, which contributes to its transmission and pathogenesis. The parasite has a sophisticated gene regulation network that enables timely expression of genes at designated stages. However, little is known about the underlying regulatory mechanisms. Here, we identified an AP2 family transcription factor named TgAP2X-4, which was crucial for parasite growth during the acute infection stage. TgAP2X-4 deletion leads to reduced expression of many genes that are normally upregulated during the M phase of the cell cycle. These include genes that encode rhoptry neck proteins that are key for parasite invasion. As a result, the Δap2X-4 mutant displayed significantly decreased efficiency of host cell invasion. Transcriptomic analyses suggested that TgAP2X-4 also regulates a large group of genes that are typically induced during chronic infection, such as BAG1 and LDH2. Given the diverse impacts on gene expression, TgAP2X-4 inactivation results in severely impaired parasite growth, as well as drastic attenuation of parasite virulence and complete inability to form chronic infection. Therefore, TgAP2X-4 represents a candidate for antitoxoplasmic drug and vaccine designs. IMPORTANCE Toxoplasma gondii has a complicated gene regulation network that allows "just in time" expression of genes to cope with the physiological needs at each stage during the complex life cycle. However, how such regulation is achieved is largely unknown. Here, we identified a transcription factor named TgAP2X-4 that is critical for the growth and life cycle progression of the parasite. Detailed analyses found that TgAP2X-4 regulated the expression of many cell cycle-regulated genes, including a subset of rhoptry genes that were essential for the parasites to enter host cells. It also regulated the expression of many genes involved in the development of chronic infection. Because of the diverse impacts on gene expression, TgAP2X-4 inactivation caused reduced parasite growth in vitro and attenuated virulence in vivo. Therefore, it is a potential target for drug or vaccine designs against Toxoplasma infections.
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Affiliation(s)
- Jingwen Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei Province, People’s Republic of China
| | - Fuqiang Fan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei Province, People’s Republic of China
| | - Lihong Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei Province, People’s Republic of China
| | - Bang Shen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei Province, People’s Republic of China
- Key Laboratory of Preventive Medicine in Hubei Province, Wuhan, Hubei Province, People’s Republic of China
- Hubei Hongshan Laboratory, Wuhan, Hubei Province, People’s Republic of China
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10
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A Role for Basigin in Toxoplasma gondii Infection. Infect Immun 2022; 90:e0020522. [PMID: 35913173 PMCID: PMC9387297 DOI: 10.1128/iai.00205-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The role of specific host cell surface receptors during Toxoplasma gondii invasion of host cells is poorly defined. Here, we interrogated the role of the well-known malarial invasion receptor, basigin, in T. gondii infection of astrocytes. We found that primary astrocytes express two members of the BASIGIN (BSG) immunoglobulin family, basigin and embigin, but did not express neuroplastin. Antibody blockade of either basigin or embigin caused a significant reduction of parasite infectivity in astrocytes. The specific role of basigin during T. gondii invasion was further examined using a mouse astrocytic cell line (C8-D30), which exclusively expresses basigin. CRISPR-mediated deletion of basigin in C8-D30 cells resulted in decreased T. gondii infectivity. T. gondii replication and invasion efficiency were not altered by basigin deficiency, but parasite attachment to astrocytes was markedly reduced. We also conducted a proteomic screen to identify T. gondii proteins that interact with basigin. Toxoplasma-encoded cyclophilins, the protein 14-3-3, and protein disulfide isomerase (TgPDI) were among the putative basigin-ligands identified. Recombinant TgPDI produced in E. coli bound to basigin and pretreatment of tachyzoites with a PDI inhibitor decreased parasite attachment to host cells. Finally, mutagenesis of the active site cysteines of TgPDI abolished enzyme binding to basigin. Thus, basigin and its related immunoglobulin family members may represent host receptors that mediate attachment of T. gondii to diverse cell types.
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11
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Nyonda MA, Kloehn J, Sosnowski P, Krishnan A, Lentini G, Maco B, Marq JB, Hannich JT, Hopfgartner G, Soldati-Favre D. Ceramide biosynthesis is critical for establishment of the intracellular niche of Toxoplasma gondii. Cell Rep 2022; 40:111224. [PMID: 35977499 PMCID: PMC9396527 DOI: 10.1016/j.celrep.2022.111224] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 06/06/2022] [Accepted: 07/26/2022] [Indexed: 11/15/2022] Open
Abstract
Toxoplasma gondii possesses sphingolipid synthesis capabilities and is equipped to salvage lipids from its host. The contribution of these two routes of lipid acquisition during parasite development is unclear. As part of a complete ceramide synthesis pathway, T. gondii expresses two serine palmitoyltransferases (TgSPT1 and TgSPT2) and a dihydroceramide desaturase. After deletion of these genes, we determine their role in parasite development in vitro and in vivo during acute and chronic infection. Detailed phenotyping through lipidomic approaches reveal a perturbed sphingolipidome in these mutants, characterized by a drastic reduction in ceramides and ceramide phosphoethanolamines but not sphingomyelins. Critically, parasites lacking TgSPT1 display decreased fitness, marked by reduced growth rates and a selective defect in rhoptry discharge in the form of secretory vesicles, causing an invasion defect. Disruption of de novo ceramide synthesis modestly affects acute infection in vivo but severely reduces cyst burden in the brain of chronically infected mice.
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Affiliation(s)
- Mary Akinyi Nyonda
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Joachim Kloehn
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Piotr Sosnowski
- Life Sciences Mass Spectrometry, Department of Inorganic and Analytical Chemistry, University of Geneva, 24 Quai Ernest Ansermet, 1211 Geneva 4, Switzerland
| | - Aarti Krishnan
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Gaëlle Lentini
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Bohumil Maco
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Jean-Baptiste Marq
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - J Thomas Hannich
- Department of Biochemistry, NCCR Chemical Biology, University of Geneva, Quai Ernest-Ansermet 30, Geneva, Switzerland
| | - Gerard Hopfgartner
- Life Sciences Mass Spectrometry, Department of Inorganic and Analytical Chemistry, University of Geneva, 24 Quai Ernest Ansermet, 1211 Geneva 4, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland.
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12
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Roling L, Flammersfeld A, Pradel G, Bennink S. The WD40-Protein PfWLP1 Ensures Stability of the PfCCp-Based Adhesion Protein Complex in Plasmodium falciparum Gametocytes. Front Cell Infect Microbiol 2022; 12:942364. [PMID: 35923798 PMCID: PMC9339629 DOI: 10.3389/fcimb.2022.942364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/23/2022] [Indexed: 11/13/2022] Open
Abstract
Members of the WD40-repeat protein family can be found in all eukaryotic proteomes where they usually serve as interaction platforms for the assembly of large protein complexes and are therefore essential for the integrity of these complexes. In the malaria parasite Plasmodium falciparum, the WD40-repeat protein PfWLP1 has been shown to interact with members of distinct adhesion protein complexes in the asexual blood stages and gametocyte stages. In this study, we demonstrate that the presence of PfWLP1 is crucial for both the stability of these gametocyte-specific adhesion complexes as well as for gametocyte maturation and gametogenesis. Using reverse genetics, we generated a PfWLP1-knockdown parasite line for functional characterization of the protein. Knockdown of PfWLP1 resulted in a slight reduction of gametocyte numbers and significantly the impaired ability of the gametocytes to exflagellate. PfWLP1-knockdown further led to reduced protein levels of the Limulus coagulation factor C-like (LCCL)-domain proteins PfCCp1 and PfCCp2, which are key components of the adhesion complexes. These findings suggest that the interaction of PfWLP1 with members of the PfCCp-based adhesion complex ensures complex stability and thereby contributes to gametocyte viability and exflagellation.
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Cova MM, Lamarque MH, Lebrun M. How Apicomplexa Parasites Secrete and Build Their Invasion Machinery. Annu Rev Microbiol 2022; 76:619-640. [PMID: 35671531 DOI: 10.1146/annurev-micro-041320-021425] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Apicomplexa are obligatory intracellular parasites that sense and actively invade host cells. Invasion is a conserved process that relies on the timely and spatially controlled exocytosis of unique specialized secretory organelles termed micronemes and rhoptries. Microneme exocytosis starts first and likely controls the intricate mechanism of rhoptry secretion. To assemble the invasion machinery, micronemal proteins-associated with the surface of the parasite-interact and form complexes with rhoptry proteins, which in turn are targeted into the host cell. This review covers the molecular advances regarding microneme and rhoptry exocytosis and focuses on how the proteins discharged from these two compartments work in synergy to drive a successful invasion event. Particular emphasis is given to the structure and molecular components of the rhoptry secretion apparatus, and to the current conceptual framework of rhoptry exocytosis that may constitute an unconventional eukaryotic secretory machinery closely related to the one described in ciliates. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Marta Mendonça Cova
- Laboratory of Pathogen Host Interactions (LPHI), CNRS, University of Montpellier, Montpellier, France;
| | - Mauld H Lamarque
- Laboratory of Pathogen Host Interactions (LPHI), CNRS, University of Montpellier, Montpellier, France;
| | - Maryse Lebrun
- Laboratory of Pathogen Host Interactions (LPHI), CNRS, University of Montpellier, Montpellier, France;
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14
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The transcriptome from asexual to sexual in vitro development of Cystoisospora suis (Apicomplexa: Coccidia). Sci Rep 2022; 12:5972. [PMID: 35396557 PMCID: PMC8993856 DOI: 10.1038/s41598-022-09714-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 03/15/2022] [Indexed: 11/08/2022] Open
Abstract
The apicomplexan parasite Cystoisospora suis is an enteropathogen of suckling piglets with woldwide distribution. As with all coccidian parasites, its lifecycle is characterized by asexual multiplication followed by sexual development with two morphologically distinct cell types that presumably fuse to form a zygote from which the oocyst arises. However, knowledge of the sexual development of C. suis is still limited. To complement previous in vitro studies, we analysed transcriptional profiles at three different time points of development (corresponding to asexual, immature and mature sexual stages) in vitro via RNASeq. Overall, transcription of genes encoding proteins with important roles in gametes biology, oocyst wall biosynthesis, DNA replication and axonema formation as well as proteins with important roles in merozoite biology was identified. A homologue of an oocyst wall tyrosine rich protein of Toxoplasma gondii was expressed in macrogametes and oocysts of C. suis. We evaluated inhibition of sexual development in a host-free culture for C. suis by antiserum specific to this protein to evaluate whether it could be exploited as a candidate for control strategies against C. suis. Based on these data, targets can be defined for future strategies to interrupt parasite transmission during sexual development.
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15
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Structure and function of an atypical homodimeric actin capping protein from the malaria parasite. Cell Mol Life Sci 2022; 79:125. [PMID: 35132495 PMCID: PMC8821504 DOI: 10.1007/s00018-021-04032-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/28/2021] [Accepted: 11/09/2021] [Indexed: 11/27/2022]
Abstract
Apicomplexan parasites, such as Plasmodium spp., rely on an unusual actomyosin motor, termed glideosome, for motility and host cell invasion. The actin filaments are maintained by a small set of essential regulators, which provide control over actin dynamics in the different stages of the parasite life cycle. Actin filament capping proteins (CPs) are indispensable heterodimeric regulators of actin dynamics. CPs have been extensively characterized in higher eukaryotes, but their role and functional mechanism in Apicomplexa remain enigmatic. Here, we present the first crystal structure of a homodimeric CP from the malaria parasite and compare the homo- and heterodimeric CP structures in detail. Despite retaining several characteristics of a canonical CP, the homodimeric Plasmodium berghei (Pb)CP exhibits crucial differences to the canonical heterodimers. Both homo- and heterodimeric PbCPs regulate actin dynamics in an atypical manner, facilitating rapid turnover of parasite actin, without affecting its critical concentration. Homo- and heterodimeric PbCPs show partially redundant activities, possibly to rescue actin filament capping in life cycle stages where the β-subunit is downregulated. Our data suggest that the homodimeric PbCP also influences actin kinetics by recruiting lateral actin dimers. This unusual function could arise from the absence of a β-subunit, as the asymmetric PbCP homodimer lacks structural elements essential for canonical barbed end interactions suggesting a novel CP binding mode. These findings will facilitate further studies aimed at elucidating the precise actin filament capping mechanism in Plasmodium.
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16
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Abstract
Toxoplasma motility is both activated and suppressed by 3′,5′-cyclic nucleotide signaling. Cyclic GMP (cGMP) signaling through Toxoplasma gondii protein kinase G (TgPKG) activates motility, whereas cyclic AMP (cAMP) signaling through TgPKAc1 inhibits motility. Despite their importance, it remains unclear how cGMP and cAMP levels are maintained in Toxoplasma. Phosphodiesterases (PDEs) are known to inactivate cyclic nucleotides and are highly expanded in the Toxoplasma genome. Here, we analyzed the expression and function of the 18-member TgPDE family in tachyzoites, the virulent life stage of Toxoplasma. We detected the expression of 11 of 18 TgPDEs, confirming prior expression studies. A knockdown screen of the TgPDE family revealed four TgPDEs that contribute to lytic Toxoplasma growth (TgPDE1, TgPDE2, TgPDE5, and TgPDE9). Depletion of TgPDE1 or TgPDE2 caused severe growth defects, prompting further investigation. While TgPDE1 was important for extracellular motility, TgPDE2 was important for host cell invasion, parasite replication, host cell egress, and extracellular motility. TgPDE1 displayed a plasma membrane/cytomembranous distribution, whereas TgPDE2 displayed an endoplasmic reticulum/cytomembranous distribution. Biochemical analysis of TgPDE1 and TgPDE2 purified from Toxoplasma lysates revealed that TgPDE1 hydrolyzes both cGMP and cAMP, whereas TgPDE2 was cAMP specific. Interactome studies of TgPDE1 and TgPDE2 indicated that they do not physically interact with each other or other TgPDEs but may be regulated by kinases and proteases. Our studies have identified TgPDE1 and TgPDE2 as central regulators of tachyzoite cyclic nucleotide levels and enable future studies aimed at determining how these enzymes are regulated and cooperate to control Toxoplasma motility and growth. IMPORTANCE Apicomplexan parasites require motility to actively infect host cells and cause disease. Cyclic nucleotide signaling governs apicomplexan motility, but it is unclear how cyclic nucleotide levels are maintained in these parasites. In search of novel regulators of cyclic nucleotides in the model apicomplexan Toxoplasma, we identified and characterized two catalytically active phosphodiesterases, TgPDE1 and TgPDE2, that are important for Toxoplasma’s virulent tachyzoite life cycle. Enzymes that generate, sense, or degrade cyclic nucleotides make attractive targets for therapies aimed at paralyzing and killing apicomplexan parasites.
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Abstract
Apicomplexans are important pathogens that cause severe infections in humans and animals. The biology and pathogeneses of these parasites have shown that proteins are intrinsically modulated during developmental transitions, physiological processes and disease progression. Also, proteins are integral components of parasite structural elements and organelles. Among apicomplexan parasites, Eimeria species are an important disease aetiology for economically important animals wherein identification and characterisation of proteins have been long-winded. Nonetheless, this review seeks to give a comprehensive overview of constitutively expressed Eimeria proteins. These molecules are discussed across developmental stages, organelles and sub-cellular components vis-à-vis their biological functions. In addition, hindsight and suggestions are offered with intention to summarise the existing trend of eimerian protein characterisation and to provide a baseline for future studies.
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18
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Mageswaran SK, Guérin A, Theveny LM, Chen WD, Martinez M, Lebrun M, Striepen B, Chang YW. In situ ultrastructures of two evolutionarily distant apicomplexan rhoptry secretion systems. Nat Commun 2021; 12:4983. [PMID: 34404783 PMCID: PMC8371170 DOI: 10.1038/s41467-021-25309-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 08/03/2021] [Indexed: 12/03/2022] Open
Abstract
Parasites of the phylum Apicomplexa cause important diseases including malaria, cryptosporidiosis and toxoplasmosis. These intracellular pathogens inject the contents of an essential organelle, the rhoptry, into host cells to facilitate invasion and infection. However, the structure and mechanism of this eukaryotic secretion system remain elusive. Here, using cryo-electron tomography and subtomogram averaging, we report the conserved architecture of the rhoptry secretion system in the invasive stages of two evolutionarily distant apicomplexans, Cryptosporidium parvum and Toxoplasma gondii. In both species, we identify helical filaments, which appear to shape and compartmentalize the rhoptries, and an apical vesicle (AV), which facilitates docking of the rhoptry tip at the parasite's apical region with the help of an elaborate ultrastructure named the rhoptry secretory apparatus (RSA); the RSA anchors the AV at the parasite plasma membrane. Depletion of T. gondii Nd9, a protein required for rhoptry secretion, disrupts the RSA ultrastructure and AV-anchoring. Moreover, T. gondii contains a line of AV-like vesicles, which interact with a pair of microtubules and accumulate towards the AV, leading to a working model for AV-reloading and discharging of multiple rhoptries. Together, our analyses provide an ultrastructural framework to understand how these important parasites deliver effectors into host cells.
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Affiliation(s)
- Shrawan Kumar Mageswaran
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Amandine Guérin
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Liam M Theveny
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - William David Chen
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Matthew Martinez
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Maryse Lebrun
- LPHI, UMR 5235 CNRS, Université de Montpellier, Montpellier, France
| | - Boris Striepen
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yi-Wei Chang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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Lentini G, Ben Chaabene R, Vadas O, Ramakrishnan C, Mukherjee B, Mehta V, Lunghi M, Grossmann J, Maco B, Visentin R, Hehl AB, Korkhov VM, Soldati-Favre D. Structural insights into an atypical secretory pathway kinase crucial for Toxoplasma gondii invasion. Nat Commun 2021; 12:3788. [PMID: 34145271 PMCID: PMC8213820 DOI: 10.1038/s41467-021-24083-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 05/31/2021] [Indexed: 02/05/2023] Open
Abstract
Active host cell invasion by the obligate intracellular apicomplexan parasites relies on the formation of a moving junction, which connects parasite and host cell plasma membranes during entry. Invading Toxoplasma gondii tachyzoites secrete their rhoptry content and insert a complex of RON proteins on the cytoplasmic side of the host cell membrane providing an anchor to which the parasite tethers. Here we show that a rhoptry-resident kinase RON13 is a key virulence factor that plays a crucial role in host cell entry. Cryo-EM, kinase assays, phosphoproteomics and cellular analyses reveal that RON13 is a secretory pathway kinase of atypical structure that phosphorylates rhoptry proteins including the components of the RON complex. Ultimately, RON13 kinase activity controls host cell invasion by anchoring the moving junction at the parasite-host cell interface.
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Affiliation(s)
- Gaëlle Lentini
- grid.8591.50000 0001 2322 4988Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Rouaa Ben Chaabene
- grid.8591.50000 0001 2322 4988Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Oscar Vadas
- grid.8591.50000 0001 2322 4988Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Chandra Ramakrishnan
- grid.7400.30000 0004 1937 0650Institute of Parasitology, University of Zurich, Zurich, Switzerland
| | - Budhaditya Mukherjee
- grid.8591.50000 0001 2322 4988Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland ,grid.429017.90000 0001 0153 2859Present Address: School of Medical Science and Technology, IIT Kharagpur, India
| | - Ved Mehta
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
| | - Matteo Lunghi
- grid.8591.50000 0001 2322 4988Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Jonas Grossmann
- grid.7400.30000 0004 1937 0650Functional Genomic Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland ,grid.419765.80000 0001 2223 3006The Swiss Institute of Bioinformatics, SIB, Lausanne, Switzerland
| | - Bohumil Maco
- grid.8591.50000 0001 2322 4988Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Rémy Visentin
- grid.8591.50000 0001 2322 4988Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Adrian B. Hehl
- grid.7400.30000 0004 1937 0650Institute of Parasitology, University of Zurich, Zurich, Switzerland
| | - Volodymyr M. Korkhov
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland ,grid.5991.40000 0001 1090 7501Paul Scherrer Institute, Villigen, Switzerland
| | - Dominique Soldati-Favre
- grid.8591.50000 0001 2322 4988Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
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20
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Loubens M, Vincensini L, Fernandes P, Briquet S, Marinach C, Silvie O. Plasmodium sporozoites on the move: Switching from cell traversal to productive invasion of hepatocytes. Mol Microbiol 2021; 115:870-881. [PMID: 33191548 PMCID: PMC8247013 DOI: 10.1111/mmi.14645] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/10/2020] [Accepted: 11/11/2020] [Indexed: 12/18/2022]
Abstract
Parasites of the genus Plasmodium, the etiological agent of malaria, are transmitted through the bite of anopheline mosquitoes, which deposit sporozoites into the host skin. Sporozoites migrate through the dermis, enter the bloodstream, and rapidly traffic to the liver. They cross the liver sinusoidal barrier and traverse several hepatocytes before switching to productive invasion of a final one for replication inside a parasitophorous vacuole. Cell traversal and productive invasion are functionally independent processes that require proteins secreted from specialized secretory organelles known as micronemes. In this review, we summarize the current understanding of how sporozoites traverse through cells and productively invade hepatocytes, and discuss the role of environmental sensing in switching from a migratory to an invasive state. We propose that timely controlled secretion of distinct microneme subsets could play a key role in successful migration and infection of hepatocytes. A better understanding of these essential biological features of the Plasmodium sporozoite may contribute to the development of new strategies to fight against the very first and asymptomatic stage of malaria.
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Affiliation(s)
- Manon Loubens
- Centre d’Immunologie et des Maladies InfectieusesSorbonne Université, INSERM, CNRS, CIMI‐ParisParisFrance
| | - Laetitia Vincensini
- Centre d’Immunologie et des Maladies InfectieusesSorbonne Université, INSERM, CNRS, CIMI‐ParisParisFrance
| | - Priyanka Fernandes
- Centre d’Immunologie et des Maladies InfectieusesSorbonne Université, INSERM, CNRS, CIMI‐ParisParisFrance
| | - Sylvie Briquet
- Centre d’Immunologie et des Maladies InfectieusesSorbonne Université, INSERM, CNRS, CIMI‐ParisParisFrance
| | - Carine Marinach
- Centre d’Immunologie et des Maladies InfectieusesSorbonne Université, INSERM, CNRS, CIMI‐ParisParisFrance
| | - Olivier Silvie
- Centre d’Immunologie et des Maladies InfectieusesSorbonne Université, INSERM, CNRS, CIMI‐ParisParisFrance
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21
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Aitfella Lahlou R, Bounechada M, Mohammedi A, Silva LR, Alves G. Dietary use of Rosmarinus officinalis and Thymus vulgaris as anticoccidial alternatives in poultry. Anim Feed Sci Technol 2021. [DOI: 10.1016/j.anifeedsci.2021.114826] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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22
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Kong L, Jiang D, He C, Xia J, Wei H, Zhou L, Peng H. TgROP18 targets IL20RB for host-defense-related-STAT3 activation during Toxoplasma gondii infection. Parasit Vectors 2020; 13:400. [PMID: 32767999 PMCID: PMC7412674 DOI: 10.1186/s13071-020-04251-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 07/20/2020] [Indexed: 11/17/2022] Open
Abstract
Background Toxoplasma gondii is an opportunistic protozoan infecting almost one-third of the world’s population. Toxoplasma gondii rhoptry protein 18 (TgROP18) is a key virulence factor determining the parasite’s acute virulence and is secreted into host cells during infection. We previously identified the interaction of TgROP18 and host cell immune-related receptor protein IL20RB, and observed the activation of STAT3 in human keratinocytes (HaCaT) cells infected by the rop16 knockout RH strain, though TgROP16 is regarded as being responsible for host STAT3 activation during T. gondii invasion. Therefore, we hypothesize TgROP18 can activate host STAT3 through binding to IL20RB. Methods CRISPR-CAS9 technology was used to generate the ROP16 and ROP18 double knockout RH strain, RH-∆rop16∆rop18. SDS-PAGE and western blot were used to detect STAT3 activation in different HaCaT cells with high endogenous IL20RB expression treated with T. gondii tachyzoites infection, recombinant ROP18, or IL-20. FRET and co-immunoprecipitation (Co-IP) was used to detect the protein-protein interaction. Results We observed that TgROP18 was involved in a synergic activation of the host JAK/STAT3 pathway together with TgROP16 in human HaCaT cells infected with T. gondii or treated with recombinant TgROP18 protein, stimulating host proinflammatory immune responses such as expression of TNF-α. The effect of recombinant ROP18 on STAT3 phosphorylation was presented in a dose-dependent manner. Additionally, TgROP18 was identified to target IL20RB on its extracellular domain. When we treated different cell lines with the recombinant ROP18, STAT3 phosphorylation could only be observed in the cells with endogenous IL20RB expression, such as HaCaT cells. Conclusions These findings indicate that TgROP18-IL20RB interaction upon T. gondii invasion was involved in STAT3 activation, which is associated with host cell defense.![]()
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Affiliation(s)
- Ling Kong
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, 510515, Guangdong Province, China
| | - Dan Jiang
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, 510515, Guangdong Province, China
| | - Cheng He
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, 510515, Guangdong Province, China
| | - Jing Xia
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, 510515, Guangdong Province, China
| | - Haixia Wei
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, 510515, Guangdong Province, China
| | - Lijuan Zhou
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, 510515, Guangdong Province, China
| | - Hongjuan Peng
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, 510515, Guangdong Province, China.
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23
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Li C, Zhao Q, Zhu S, Wang Q, Wang H, Yu S, Yu Y, Liang S, Zhao H, Huang B, Dong H, Han H. Eimeria tenella Eimeria-specific protein that interacts with apical membrane antigen 1 (EtAMA1) is involved in host cell invasion. Parasit Vectors 2020; 13:373. [PMID: 32711572 PMCID: PMC7382093 DOI: 10.1186/s13071-020-04229-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 07/15/2020] [Indexed: 11/10/2022] Open
Abstract
Background Avian coccidiosis is a widespread, economically significant disease of poultry, caused by several Eimeria species. These parasites have complex and diverse life-cycles that require invasion of their host cells. This is mediated by various proteins secreted from apical secretory organelles. Apical membrane antigen 1 (AMA1), which is released from micronemes and is conserved across all apicomplexans, plays a central role in the host cell invasion. In a previous study, some putative EtAMA1-interacting proteins of E. tenella were screened. In this study, we characterized one putative EtAMA1-interacting protein, E. tenella Eimeria -specific protein (EtEsp). Methods Bimolecular fluorescence complementation (BiFC) and glutathione S-transferase (GST) fusion protein pull-down (GST pull-down) were used to confirm the interaction between EtAMA1 and EtEsp in vivo and in vitro. The expression of EtEsp was analyzed in different developmental stages of E. tenella with quantitative PCR and western blotting. The secretion of EtEsp protein was tested with staurosporine when sporozoites were incubated in complete medium at 41 °C. The localization of EtEsp was analyzed with an immunofluorescence assay (IFA). An in vitro invasion inhibition assay was conducted to assess the ability of antibodies against EtEsp to inhibit cell invasion by E. tenella sporozoites. Results The interaction between EtAMA1 and EtEsp was confirmed with BiFC and by GST pull-down. Our results show that EtEsp is differentially expressed during distinct phases of the parasite life-cycle. IFA showed that the EtEsp protein is mainly distributed on the parasite surface, and that the expression of this protein increases during the development of the parasite in the host cells. Using staurosporine, we showed that EtEsp is a secreted protein, but not from micronemes. In inhibition tests, a polyclonal anti-rEtEsp antibody attenuated the capacity of E. tenella to invade host cells. Conclusion In this study, we show that EtEsp interacts with EtAMA1 and that the protein is secreted protein, but not from micronemes. The protein participates in sporozoite invasion of host cells and is maybe involved in the growth of the parasite. These data have implications for the use of EtAMA1 or EtAMA1-interacting proteins as targets in intervention strategies against avian coccidiosis.![]()
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Affiliation(s)
- Cong Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Qiping Zhao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Shunhai Zhu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Qingjie Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Haixia Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Shuilan Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Yu Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China.,College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Shashan Liang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China.,College of Life and Environment Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Huanzhi Zhao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Bing Huang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Hui Dong
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China.
| | - Hongyu Han
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China.
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24
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The role of macrophage reprogramming induced by GRA15 II, a polypeptide effector molecule of Toxoplasma gondii, in liver diseases in model mice. Cell Mol Immunol 2020; 17:788-790. [PMID: 32265514 DOI: 10.1038/s41423-020-0422-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 03/17/2020] [Indexed: 11/08/2022] Open
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Tian Y, Li F, Guo J, Hu Y, Shu X, Xia Y, Kang T, Yu L, Liu Q, Nie Z, Wang S, Ao Y, An X, Zhao J, He L. Identification and characterizations of a rhoptries neck protein 5 (BoRON5) in Babesia orientalis. Parasitol Int 2020; 77:102106. [PMID: 32179136 DOI: 10.1016/j.parint.2020.102106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/06/2020] [Accepted: 03/11/2020] [Indexed: 10/24/2022]
Abstract
Babesiosis caused by Babesia orientalis is one of the most serious parasitic diseases of water buffalo in the central and south part of China. Rhoptry neck proteins (RONs) are very important protein components to form a complex moving junction (MJ) which mainly participate in the invasion processes in apicomplexan parasites. Aimed to the further investigation of the function of BoRON proteins in B. orientalis, in this study, BoRON5 was characterized. A truncated 921 bp fragment of BoRON5 with predicted antigenic epitopes was cloned and inserted into pSUMO expression vector. Recombinant protein rSUMO-BoRON5 was purified from Escherichia coli. and used to produce antisera in Kunming mice. rSUMO-BoRON5 showed strong immunosignals when blotted with the positive serum from B. orientalis-infected water buffalo. Antisera raised in Kunming mice against rSUMO-BoRON5 could detect the native BoRON5 in parasite lysates. Immuofluorescence assay showed that mice antisera of rSUMO-BoRON5 could detect merozoite in B. orientalis infected water buffalo erythrocytes. This study provides useful information for the further investigation of the BoRON5 function during B. orientalis invasion of water buffalo.
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Affiliation(s)
- Yu Tian
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Fangjie Li
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei 430070, China
| | - Jiaying Guo
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei 430070, China
| | - Yanli Hu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei 430070, China
| | - Xiang Shu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei 430070, China
| | - Yinjun Xia
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei 430070, China
| | - Ting Kang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei 430070, China
| | - Long Yu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei 430070, China
| | - Qin Liu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei 430070, China
| | - Zheng Nie
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei 430070, China
| | - Sen Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei 430070, China
| | - Yangsiqi Ao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei 430070, China
| | - Xiaomeng An
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei 430070, China
| | - Junlong Zhao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei 430070, China; Key Laboratory of Animal Epidemical Disease and Infectious Zoonoses, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Lan He
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan, Hubei 430070, China; Key Laboratory of Animal Epidemical Disease and Infectious Zoonoses, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
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RhopH3, rhoptry gene conserved in the free-living alveolate flagellate Colpodella sp. (Apicomplexa). Eur J Protistol 2019; 71:125637. [PMID: 31689662 DOI: 10.1016/j.ejop.2019.125637] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 08/05/2019] [Accepted: 08/20/2019] [Indexed: 11/22/2022]
Abstract
In this study, we investigated morphological, immunological and molecular characteristics of Colpodella sp. (American Type Culture Collection 50594) in a diprotist culture containing Bodo caudatus as prey using Plasmodium rhoptry specific antibodies and oligonucleotide primers targeting Plasmodium falciparum rhoptry genes. In culture, Colpodella sp. attached to its prey using the apical end with attachment lasting for approximately 20 min while the cytoplasmic contents of the prey were aspirated into the posterior food vacuole of Colpodella sp. Encystment of Colpodella sp. was observed following feeding. Indirect immunofluorescence assay (IFA) and confocal microscopy using P. falciparum rhoptry specific antibodies showed intense reactivity with cytoplasmic vesicles of Colpodella sp. Bodo caudatus from diprotist and monoprotist (ATCC 30395) cultures showed weak background reactivity. Giemsa staining permitted differentiation of both protists. Genomic DNA isolated from the diprotist culture was used in polymerase chain reaction (PCR) with oligonucleotide primers targeting the P. falciparum rhoptry genes RhopH3, RhopH1/Clag3.2 and RAMA. Primers targeting exon 7 of the P. falciparum RhopH3 gene amplified an approximately 2 kb DNA fragment from the diprotist DNA template. DNA sequence and BLAST search analysis of the amplified product from diprotist DNA identified the RhopH3 gene demonstrating that the RhopH3 gene is conserved in Colpodella sp.
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RON2, a novel gene in Babesia bigemina, contains conserved, immunodominant B-cell epitopes that induce antibodies that block merozoite invasion. Parasitology 2019; 146:1646-1654. [PMID: 31452491 PMCID: PMC6786967 DOI: 10.1017/s0031182019001161] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Bovine babesiosis is the most important protozoan disease transmitted by ticks. In Plasmodium falciparum, another Apicomplexa protozoan, the interaction of rhoptry neck protein 2 (RON2) with apical membrane antigen-1 (AMA-1) has been described to have a key role in the invasion process. To date, RON2 has not been described in Babesia bigemina, the causal agent of bovine babesiosis in the Americas. In this work, we found a ron2 gene in the B. bigemina genome. RON2 encodes a protein that is 1351 amino acids long, has an identity of 64% (98% coverage) with RON2 of B. bovis and contains the CLAG domain, a conserved domain in Apicomplexa. B. bigemina ron2 is a single copy gene and it is transcribed and expressed in blood stages as determined by RT-PCR, Western blot, and confocal microscopy. Serum samples from B. bigemina-infected bovines were screened for the presence of RON2-specific antibodies, showing the recognition of conserved B-cell epitopes. Importantly, in vitro neutralization assays showed an inhibitory effect of RON2-specific antibodies on the red blood cell invasion by B. bigemina. Therefore, RON2 is a novel antigen in B. bigemina and contains conserved B-cell epitopes, which induce antibodies that inhibit merozoite invasion.
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Hidalgo-Ruiz M, Suarez CE, Mercado-Uriostegui MA, Hernandez-Ortiz R, Ramos JA, Galindo-Velasco E, León-Ávila G, Hernández JM, Mosqueda J. Babesia bovis RON2 contains conserved B-cell epitopes that induce an invasion-blocking humoral immune response in immunized cattle. Parasit Vectors 2018; 11:575. [PMID: 30390674 PMCID: PMC6215676 DOI: 10.1186/s13071-018-3164-2] [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: 07/10/2018] [Accepted: 10/22/2018] [Indexed: 11/10/2022] Open
Abstract
Background Babesia bovis belongs to the phylum Apicomplexa and is the major causal agent of bovine babesiosis, the most important veterinary disease transmitted by arthropods. In apicomplexan parasites, the interaction between AMA1 and RON2 is necessary for the invasion process, and it is a target for vaccine development. In B. bovis, the existence of AMA1 has already been reported; however, the presence of a homolog of RON2 is unknown. The aim of this study was to characterize RON2 in B. bovis. Results The B. bovis ron2 gene has a similar synteny with the orthologous gene in the B. bigemina genome. The entire ron2 gene was sequenced from different B. bovis strains showing > 99% similarity at the amino acid and nucleotide level among all the sequences obtained, including the characteristic CLAG domain for cytoadherence in the amino acid sequence, as is described in other Apicomplexa. The in silico transcription analysis showed similar levels of transcription between attenuated and virulent B. bovis strains, and expression of RON2 was confirmed by western blot in the B. bovis T3Bo virulent strain. Four conserved peptides, containing predicted B-cell epitopes in hydrophilic regions of the protein, were designed and chemically synthesized. The humoral immune response generated by the synthetic peptides was characterized in bovines, showing that anti-RON2 antibodies against peptides recognized intraerythrocytic merozoites of B. bovis. Only peptides P2 and P3 generated partially neutralizing antibodies that had an inhibitory effect of 28.10% and 21.42%, respectively, on the invasion process of B. bovis in bovine erythrocytes. Consistently, this effect is additive since inhibition increased to 42.09% when the antibodies were evaluated together. Finally, P2 and P3 peptides were also recognized by 83.33% and 87.77%, respectively, of naturally infected cattle from endemic areas. Conclusions The data support RON2 as a novel B. bovis vaccine candidate antigen that contains conserved B-cell epitopes that elicit partially neutralizing antibodies. Electronic supplementary material The online version of this article (10.1186/s13071-018-3164-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mario Hidalgo-Ruiz
- Immunology and Vaccines Laboratory, C. A. Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Carretera a Chichimequillas, Ejido Bolaños, 76140, Queretaro, Queretaro, Mexico
| | - Carlos E Suarez
- Animal Disease Research Unit, USDA-ARS, 3003 ADBF, WSU, P. O. Box 647030, Pullman, WA, 99164-6630, USA
| | - Miguel A Mercado-Uriostegui
- Immunology and Vaccines Laboratory, C. A. Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Carretera a Chichimequillas, Ejido Bolaños, 76140, Queretaro, Queretaro, Mexico
| | - Ruben Hernandez-Ortiz
- CENID-Parasitologia Veterinaria / INIFAP, Carretera federal Cuernavaca-Cuautla #8534, Col. Progreso, 62550, Jiutepec, Morelos, Mexico
| | - Juan Alberto Ramos
- CENID-Parasitologia Veterinaria / INIFAP, Carretera federal Cuernavaca-Cuautla #8534, Col. Progreso, 62550, Jiutepec, Morelos, Mexico
| | - Edelmira Galindo-Velasco
- Facultad de Medicina Veterinaria y Zootecnia, Universidad de Colima, Km. 40 carretera Colima-Manzanillo, 28100, Tecoman, Colima, Mexico
| | - Gloria León-Ávila
- Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Carpio y Plan de Ayala, Col. Casco de Santo Tomás, 11340, Mexico City, Mexico
| | - José Manuel Hernández
- Departamento de Biología Celular, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, Av. IPN 2508, Col. San Pedro Zacatenco, 07360, Mexico City, Mexico
| | - Juan Mosqueda
- Immunology and Vaccines Laboratory, C. A. Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Carretera a Chichimequillas, Ejido Bolaños, 76140, Queretaro, Queretaro, Mexico.
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Foroutan M, Zaki L, Ghaffarifar F. Recent progress in microneme-based vaccines development against Toxoplasma gondii. Clin Exp Vaccine Res 2018; 7:93-103. [PMID: 30112348 PMCID: PMC6082678 DOI: 10.7774/cevr.2018.7.2.93] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/18/2018] [Accepted: 07/06/2018] [Indexed: 11/25/2022] Open
Abstract
Toxoplasmosis is a cosmopolitan zoonotic disease, which infect several warm-blooded mammals. More than one-third of the human population are seropositive worldwide. Due to the high seroprevalence of Toxoplasma gondii infection worldwide, the resulting clinical, mental, and economical complications, as well as incapability of current drugs in the elimination of parasites within tissue cysts, the development of a vaccine against T. gondii would be critical. In the past decades, valuable advances have been achieved in order to identification of vaccine candidates against T. gondii infection. Microneme proteins (MICs) secreted by the micronemes play a critical role in the initial stages of host cell invasion by parasites. In this review, we have summarized the recent progress for MIC-based vaccines development, such as DNA vaccines, recombinant protein vaccines, vaccines based on live-attenuated vectors, and prime-boost strategy in different mouse models. In conclusion, the use of live-attenuated vectors as vehicles to deliver and express the target gene and prime-boost regimens showed excellent outcomes in the development of vaccines against toxoplasmosis, which need more attention in the future studies.
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Affiliation(s)
- Masoud Foroutan
- Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Leila Zaki
- Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Fatemeh Ghaffarifar
- Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
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30
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Brasil TR, Freire-de-Lima CG, Morrot A, Vetö Arnholdt AC. Host- Toxoplasma gondii Coadaptation Leads to Fine Tuning of the Immune Response. Front Immunol 2017; 8:1080. [PMID: 28955329 PMCID: PMC5601305 DOI: 10.3389/fimmu.2017.01080] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 08/21/2017] [Indexed: 12/22/2022] Open
Abstract
Toxoplasma gondii has successfully developed strategies to evade host's immune response and reach immune privileged sites, which remains in a controlled environment inside quiescent tissue cysts. In this review, we will approach several known mechanisms used by the parasite to modulate mainly the murine immune system at its favor. In what follows, we review recent findings revealing interference of host's cell autonomous immunity and cell signaling, gene expression, apoptosis, and production of microbicide molecules such as nitric oxide and oxygen reactive species during parasite infection. Modulation of host's metalloproteinases of extracellular matrix is also discussed. These immune evasion strategies are determinant to parasite dissemination throughout the host taking advantage of cells from the immune system to reach brain and retina, crossing crucial hosts' barriers.
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Affiliation(s)
- Thaís Rigueti Brasil
- Laboratório de Biologia do Reconhecer, Universidade Estadual do Norte Fluminense, Rio de Janeiro, Brazil
| | | | - Alexandre Morrot
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
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He C, Kong L, Zhou L, Xia J, Wei H, Liu M, Peng H. Host Cell Vimentin Restrains Toxoplasma gondii Invasion and Phosphorylation of Vimentin is Partially Regulated by Interaction with TgROP18. Int J Biol Sci 2017; 13:1126-1137. [PMID: 29104504 PMCID: PMC5666328 DOI: 10.7150/ijbs.21247] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 06/23/2017] [Indexed: 12/14/2022] Open
Abstract
The obligate intracellular parasite, Toxoplasma gondii, manipulates the cytoskeleton of its host cells to facilitate infection. A significant rearrangement of host cell vimentin around Toxoplasma parasitophorous vacuoles is observed during the course of infection. ROP18 (TgROP18) is a serine-threonine kinase secreted by T. gondii rhoptry and a major virulence factor; however, the mechanisms by which this kinase modulates host factors remain poorly understood. Different and dynamic patterns of vimentin solubility, phosphorylation, and expression levels were observed in host cells infected with T. gondii strain RH and RH Δrop18 strains, suggesting that TgROP18 contributes to the regulation of these dynamic patterns. Additionally, host cell vimentin was demonstrated to interact with and be phosphorylated by TgROP18. A significant increase in T. gondii infection rate was observed in vimentin knockout human brain microvessel endothelial cells (HBMEC), while vimentin knockout or knock down in host cells had no impact on parasite proliferation and egress. These results indicate that host cell vimentin can inhibit T. gondii invasion. Interestingly, western blotting of different mouse tissues indicated that the lowest vimentin expression level was present in the brain, which may explain the mechanism underlying the nervous system tropism of T. gondii, and the phenomenon of huge cyst burdens developing in the mouse brain during chronic infection.
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Affiliation(s)
- Cheng He
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, 510515, China
| | - Ling Kong
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, 510515, China
| | - Lijuan Zhou
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, 510515, China
| | - Jing Xia
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, 510515, China
| | - Haixia Wei
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, 510515, China
| | - Min Liu
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, 510515, China
| | - Hongjuan Peng
- Department of Pathogen Biology, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, Guangdong Province, 510515, China
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Molecular Cloning and Characterization of Babesia orientalis Rhoptry Neck 2 BoRON2 Protein. J Parasitol Res 2017; 2017:7259630. [PMID: 28775897 PMCID: PMC5523350 DOI: 10.1155/2017/7259630] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 04/12/2017] [Accepted: 04/30/2017] [Indexed: 11/24/2022] Open
Abstract
Babesiosis caused by Babesia orientalis is one of the most prevalent infections of water buffalo transmitted by Rhipicephalus haemaphysaloides causing a parasitic and hemolytic disease. The organelles proteins localized in apical membrane especially rhoptries neck and microneme protein form a complex called moving junction important during invasion process of parasites belonging to apicomplexan group, including Babesia species. A truncated fragment coding a 936 bps fragment was cloned in pMD-19T and subcloned into pET32 (a)+ expression vector, expressed in E. coli BL21. Purified recombinant BoRON2 was used to produce polyclonal antibody against BoRON2. Here, we identified the full sequence of gene encoding the rhoptry neck 2 protein that we named BoRON2 which is 4035 bp in full-length open reading frame without introns, encoding a polypeptide of 1345 amino acids. Western blot of rBoRON2 probed with buffalo positive serum analysis revealed a band of around 150 kDa in parasite lysates, suggesting an active involvement during invasion process. These findings most likely are constructive in perspective of ongoing research focused particularly on water buffalo babesiosis prevention and therapeutics and globally provide new information for genes comparative analysis.
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Abstract
Early electron microscopy studies revealed the elaborate cellular features that define the unique adaptations of apicomplexan parasites. Among these were bulbous rhoptry (ROP) organelles and small, dense granules (GRAs), both of which are secreted during invasion of host cells. These early morphological studies were followed by the exploration of the cellular contents of these secretory organelles, revealing them to be comprised of highly divergent protein families with few conserved domains or predicted functions. In parallel, studies on host-pathogen interactions identified many host signaling pathways that were mysteriously altered by infection. It was only with the advent of forward and reverse genetic strategies that the connections between individual parasite effectors and the specific host pathways that they targeted finally became clear. The current repertoire of parasite effectors includes ROP kinases and pseudokinases that are secreted during invasion and that block host immune pathways. Similarly, many secretory GRA proteins alter host gene expression by activating host transcription factors, through modification of chromatin, or by inducing small noncoding RNAs. These effectors highlight novel mechanisms by which T. gondii has learned to harness host signaling to favor intracellular survival and will guide future studies designed to uncover the additional complexity of this intricate host-pathogen interaction.
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Chen AL, Moon AS, Bell HN, Huang AS, Vashisht AA, Toh JY, Lin AH, Nadipuram SM, Kim EW, Choi CP, Wohlschlegel JA, Bradley PJ. Novel insights into the composition and function of the Toxoplasma IMC sutures. Cell Microbiol 2017; 19:10.1111/cmi.12678. [PMID: 27696623 PMCID: PMC5909696 DOI: 10.1111/cmi.12678] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 08/19/2016] [Accepted: 09/28/2016] [Indexed: 12/29/2022]
Abstract
The Toxoplasma inner membrane complex (IMC) is a specialized organelle underlying the parasite's plasma membrane that consists of flattened rectangular membrane sacs that are sutured together and positioned atop a supportive cytoskeleton. We have previously identified a novel class of proteins localizing to the transverse and longitudinal sutures of the IMC, which we named IMC sutures components (ISCs). Here, we have used proximity-dependent biotin identification at the sutures to better define the composition of this IMC subcompartment. Using ISC4 as bait, we demonstrate biotin-dependent labeling of the sutures and have uncovered two new ISCs. We also identified five new proteins that exclusively localize to the transverse sutures that we named transverse sutures components (TSCs), demonstrating that components of the IMC sutures consist of two groups: those that localize to the transverse and longitudinal sutures (ISCs) and those residing only in the transverse sutures (TSCs). In addition, we functionally analyze the ISC protein ISC3 and demonstrate that ISC3-null parasites have morphological defects and reduced fitness in vitro. Most importantly, Δisc3 parasites exhibit a complete loss of virulence in vivo. These studies expand the known composition of the IMC sutures and highlight the contribution of ISCs to the ability of the parasite to proliferate and cause disease.
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Affiliation(s)
- Allan L. Chen
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, USA 90095
| | - Andy S. Moon
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, USA 90095
| | - Hannah N. Bell
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, USA 90095
| | - Amy S. Huang
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, USA 90095
| | - Ajay A. Vashisht
- Department of Biological Chemistry and Institute of Genomics and Proteomics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA 90095
| | - Justin Y. Toh
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, USA 90095
| | - Andrew H. Lin
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, USA 90095
| | - Santhosh M. Nadipuram
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, USA 90095
| | - Elliot W. Kim
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, USA 90095
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, USA 90095
| | - Charles P. Choi
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, USA 90095
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, USA 90095
| | - James A. Wohlschlegel
- Department of Biological Chemistry and Institute of Genomics and Proteomics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA 90095
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, USA 90095
| | - Peter J. Bradley
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California, USA 90095
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, USA 90095
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Yang ASP, Boddey JA. Molecular mechanisms of host cell traversal by malaria sporozoites. Int J Parasitol 2016; 47:129-136. [PMID: 27825827 DOI: 10.1016/j.ijpara.2016.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/22/2016] [Accepted: 09/05/2016] [Indexed: 11/19/2022]
Abstract
Malaria is a pernicious infectious disease caused by apicomplexan parasites of the genus Plasmodium. Each year, malaria afflicts over 200million people, causing considerable morbidity, loss to gross domestic product of endemic countries, and more than 420,000 deaths. A central feature of the virulence of malaria parasites is the ability of sporozoite forms injected by a mosquito to navigate from the inoculation site in the skin through host tissues to infect the liver. The ability for sporozoites to traverse through different host cell types is very important for the successful development of parasites within the mammalian host. Over the past decade, our understanding of the role of host cell traversal has become clearer through important studies with rodent models of malaria. However, we still do not understand the stepwise process of host cell entry and exit or know the molecular mechanisms governing each step. We know even less about cell traversal by malaria parasite species that infect humans. Here, we review current knowledge regarding the role and molecular mechanisms of sporozoite cell traversal and highlight recent advances that prompt new ways of thinking about this important process.
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Affiliation(s)
- Annie S P Yang
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Justin A Boddey
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia.
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Han H, Xue P, Dong H, Zhu S, Zhao Q, Huang B. Screening and characterization of apical membrane antigen 1 interacting proteins in Eimeria tenella. Exp Parasitol 2016; 170:116-124. [PMID: 27693220 DOI: 10.1016/j.exppara.2016.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/15/2016] [Accepted: 09/27/2016] [Indexed: 10/20/2022]
Abstract
Avian coccidiosis is a widespread and economically significant disease of poultry. It is an enteric disease caused by several protozoan Eimeria species. Eimeria belongs to the phylum Apicomplexa, which exhibits an unusual mechanism of host cell invasion. During invasion of host cells, the protein apical membrane antigen 1 (AMA1) is essential for invasion of Toxoplasma gondii and Plasmodium. Contrary to the roles of AMA1 during host cell invasion in T. gondii and Plasmodium, the precise functions of Eimeria AMA1 (EtAMA1) are unclear. In order to study the functions of EtAMA1, a yeast two-hybrid cDNA library was constructed from E. tenella sporozoites. The EtAMA1 ectodomain was cloned into the pGBKT7 vector to construct the bait plasmid pGBKT7- EtAMA1. Autoactivation and toxicity of the bait protein in yeast cells were tested by comparison with the pGBKT7 empty vector. Expression of the bait protein was detected by western blots. The bait plasmid pGBKT7-EtAMA1 was used to screen yeast two-hybrid cDNA library from E. tenella sporozoites. After multiple screenings with high-screening-rate medium and exclusion of false-positive plasmids, positive preys were sequenced and analyzed using BLAST. We obtained 14 putative EtAMA1-interacting proteins including E. tenella acidic microneme protein2 (EtMIC2), E. tenella putative cystathionine beta-synthase, E. tenella Eimeria-specific protein, four E. tenella conserved hypothetical proteins (one in the serine/threonine protein kinase family) and seven unknown proteins. Gene Ontology analysis indicated that two known proteins were associated with metabolic process, pyridoxal phosphate binding and protein phosphorylation. Functional analysis indicated EtMIC2 was implicated in parasite motility, migration, recognition and invasion of host cells. The data suggested that EtAMA1 may be important during host cell invasion, but also involved in other biological processes.
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Affiliation(s)
- Hongyu Han
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Pu Xue
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Hui Dong
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Shunhai Zhu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Qiping Zhao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China
| | - Bing Huang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Minhang, Shanghai, 200241, PR China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, PR China.
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Graindorge A, Frénal K, Jacot D, Salamun J, Marq JB, Soldati-Favre D. The Conoid Associated Motor MyoH Is Indispensable for Toxoplasma gondii Entry and Exit from Host Cells. PLoS Pathog 2016; 12:e1005388. [PMID: 26760042 PMCID: PMC4711953 DOI: 10.1371/journal.ppat.1005388] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 12/17/2015] [Indexed: 11/23/2022] Open
Abstract
Many members of the phylum of Apicomplexa have adopted an obligate intracellular life style and critically depend on active invasion and egress from the infected cells to complete their lytic cycle. Toxoplasma gondii belongs to the coccidian subgroup of the Apicomplexa, and as such, the invasive tachyzoite contains an organelle termed the conoid at its extreme apex. This motile organelle consists of a unique polymer of tubulin fibres and protrudes in both gliding and invading parasites. The class XIV myosin A, which is conserved across the Apicomplexa phylum, is known to critically contribute to motility, invasion and egress from infected cells. The MyoA-glideosome is anchored to the inner membrane complex (IMC) and is assumed to translocate the components of the circular junction secreted by the micronemes and rhoptries, to the rear of the parasite. Here we comprehensively characterise the class XIV myosin H (MyoH) and its associated light chains. We show that the 3 alpha-tubulin suppressor domains, located in MyoH tail, are necessary to anchor this motor to the conoid. Despite the presence of an intact MyoA-glideosome, conditional disruption of TgMyoH severely compromises parasite motility, invasion and egress from infected cells. We demonstrate that MyoH is necessary for the translocation of the circular junction from the tip of the parasite, where secretory organelles exocytosis occurs, to the apical position where the IMC starts. This study attributes for the first time a direct function of the conoid in motility and invasion, and establishes the indispensable role of MyoH in initiating the first step of motility along this unique organelle, which is subsequently relayed by MyoA to enact effective gliding and invasion. The Apicomplexa phylum groups important pathogens that infect humans and animals. Host cell invasion and egress from infected cells are key events in the lytic cycle of these obligate intracellular parasites. Host cell entry is powered by gliding motility and initiated by the discharge of apical secretory organelles at the site of contact with the host cell. Anchored to the parasite pellicle, the glideosome composed of myosin A and the gliding associated proteins is the molecular machine which translocates the secreted adhesins from the apical to the posterior pole of the parasite and hence propels the parasite into the host cell. Toxoplasma gondii exhibits a helical form of gliding motility and as member of the coccidian-subgroup of Apicomplexa possesses an apical organelle called the conoid, which protrudes during invasion and egress and consists in helically organized polymer of tubulin fibers. We have deciphered here the function of a novel myosin associated to the microtubules composing the conoid. Myosin H is essential and prerequisite for motility, invasion and egress from infected cells. This unusual motor links actin- and tubulin-based cytoskeletons and uncovers a direct role of the conoid in motility and invasion.
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Affiliation(s)
- Arnault Graindorge
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Karine Frénal
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Damien Jacot
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Julien Salamun
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Jean Baptiste Marq
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- * E-mail:
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Maindola P, Jamal S, Grover A. Cheminformatics Based Machine Learning Models for AMA1-RON2 Abrogators for Inhibiting Plasmodium falciparum Erythrocyte Invasion. Mol Inform 2015; 34:655-64. [PMID: 27490966 DOI: 10.1002/minf.201400139] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 02/21/2015] [Indexed: 01/15/2023]
Abstract
Malaria remains a dreadful disease by putting every year about 3.4 billion people at risk and resulting into mortality of 627 thousand people worldwide. Existing therapies based upon Quinines and Artemisinin-based combination therapies have started showing resistance, pressing the need for search of anti-malarials with different mechanisms of action. In this respect erythrocyte invasion by Plasmodium is immensely crucial, as being obligate intracellular parasite it must invade host cells. This process is mediated by interaction between conserved Apical Membrane Antigen (AMA1) and Rhoptry Neck (RON2) protein, which is compulsory for successful invasion of erythrocyte by Plasmodium and manifestation of the disease Malaria. Here, using the physicochemical properties of the compounds available from a confirmatory high throughput screening, which were tested for their disruption capability of this crucial molecular interaction, we trained supervised classifiers and validated their robustness by various statistical parameters. Best model was used for screening new compounds from Traditional Chinese Medicine Database. Some of the best hits already find their use as anti-malarials and the model predicts that an essential part of their effectiveness is likely due to inhibition of AMA1-RON2 interaction. Pharmacophoric features have also been identified to ease further designing of possible leads in an effective way.
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Affiliation(s)
- Priyank Maindola
- School of Biotechnology, Jawaharlal Nehru University, New Delhi-110067, India phone/fax: +91-11-26738728; fax: +91-11-26702040
| | - Salma Jamal
- School of Biotechnology, Jawaharlal Nehru University, New Delhi-110067, India phone/fax: +91-11-26738728; fax: +91-11-26702040
| | - Abhinav Grover
- School of Biotechnology, Jawaharlal Nehru University, New Delhi-110067, India phone/fax: +91-11-26738728; fax: +91-11-26702040.
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MIC3, a novel cross-protective antigen expressed in Toxoplasma gondii and Neospora caninum. Parasitol Res 2015; 114:3791-9. [DOI: 10.1007/s00436-015-4609-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 06/25/2015] [Indexed: 11/30/2022]
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Abstract
UNLABELLED Apicomplexan parasites actively invade host cells using a mechanism predicted to be powered by a parasite actin-dependent myosin motor. In the model apicomplexan Toxoplasma gondii, inducible knockout of the actin gene, ACT1, was recently demonstrated to limit but not completely abolish invasion. This observation has led to the provocative suggestion that T. gondii possesses alternative, ACT1-independent invasion pathways. Here, we dissected the residual invasive ability of Δact1 parasites. Surprisingly, we were able to detect residual ACT1 protein in inducible Δact1 parasites as long as 5 days after ACT1 deletion. We further found that the longer Δact1 parasites were propagated after ACT1 deletion, the more severe an invasion defect was observed. Both findings are consistent with the quantity of residual ACT1 retained in Δact1 parasites being responsible for their invasive ability. Furthermore, invasion by the Δact1 parasites was also sensitive to the actin polymerization inhibitor cytochalasin D. Finally, there was no clear defect in attachment to host cells or moving junction formation by Δact1 parasites. However, Δact1 parasites often exhibited delayed entry into host cells, suggesting a defect specific to the penetration stage of invasion. Overall, our results support a model where residual ACT1 protein retained in inducible Δact1 parasites facilitates their limited invasive ability and confirm that parasite actin is essential for efficient penetration into host cells during invasion. IMPORTANCE The prevailing model for apicomplexan invasion has recently been suggested to require major revision, based on studies where core components of the invasion machinery were genetically disrupted using a Cre-Lox-based inducible knockout system. For the myosin component of the motor thought to power invasion, an alternative parasite myosin was recently demonstrated to functionally compensate for loss of the primary myosin involved in invasion. Here, we highlight a second mechanism that can account for the surprising ability of parasites to invade after genetic disruption of core invasion machinery. Specifically, residual actin protein present in inducible knockout parasites appears able to support their limited invasion of host cells. Our results have important implications for the interpretation of the apicomplexan invasion model and also highlight significant considerations when analyzing the phenotypes of inducible knockout parasites generated using Cre-Lox technology.
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Arévalo-Pinzón G, Bermúdez M, Curtidor H, Patarroyo MA. The Plasmodium vivax rhoptry neck protein 5 is expressed in the apical pole of Plasmodium vivax VCG-1 strain schizonts and binds to human reticulocytes. Malar J 2015; 14:106. [PMID: 25888962 PMCID: PMC4359499 DOI: 10.1186/s12936-015-0619-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/22/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Different proteins derived from the membrane or the apical organelles become involved in malarial parasite invasion of host cells. Among these, the rhoptry neck proteins (RONs) interact with a protein component of the micronemes to enable the formation of a strong bond which is crucial for the parasite's successful invasion. The present study was aimed at identifying and characterizing the RON5 protein in Plasmodium vivax and evaluating its ability to bind to reticulocytes. METHODS Taking the Plasmodium falciparum and Plasmodium knowlesi RON5 amino acid sequences as template, an in-silico search was made in the P. vivax genome for identifying the orthologous gene. Different molecular tools were used for experimentally ascertaining pvron5 gene presence and transcription in P. vivax VCG-1 strain schizonts. Polyclonal antibodies against PvRON5 peptides were used for evaluating protein expression (by Western blot) and sub-cellular localization (by immunofluorescence). A 33 kDa PvRON5 fragment was expressed in Escherichia coli and used for evaluating the reactivity of sera from patients infected by P. vivax. Two assays were made for determining the RON5 recombinant fragment's ability to bind to reticulocyte-enriched human umbilical cord samples. RESULTS The pvron5 gene (3,477 bp) was transcribed in VCG-1 strain schizonts and encoded a ~133 kDa protein which was expressed in the rhoptry neck of VCG-1 strain late schizonts, together with PvRON2 and PvRON4. Polyclonal sera against PvRON5 peptides specifically detected ~85 and ~30 kDa fragments in parasite lysate, thereby suggesting proteolytic processing in this protein. Comparative analysis of VCG-1 strain PvRON5 with other P. vivax strains having different geographic localizations suggested its low polymorphism regarding other malarial antigens. A recombinant fragment of the PvRON5 protein (rPvRON5) was recognized by sera from P. vivax-infected patients and bound to red blood cells, having a marked preference for human reticulocytes. CONCLUSIONS The pvron5 gene is transcribed in the VCG-1 strain, the encoded protein is expressed at the parasite's apical pole and might be participating in merozoite invasion of host cells, taking into account its marked binding preference for human reticulocytes.
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Affiliation(s)
- Gabriela Arévalo-Pinzón
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50 # 26-20, Bogotá, Colombia. .,Universidad del Rosario, Carrera 24 # 63C-69, Bogotá, Colombia.
| | - Maritza Bermúdez
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50 # 26-20, Bogotá, Colombia. .,Universidad del Rosario, Carrera 24 # 63C-69, Bogotá, Colombia.
| | - Hernando Curtidor
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50 # 26-20, Bogotá, Colombia. .,Universidad del Rosario, Carrera 24 # 63C-69, Bogotá, Colombia.
| | - Manuel A Patarroyo
- Fundación Instituto de Inmunología de Colombia (FIDIC), Carrera 50 # 26-20, Bogotá, Colombia. .,Universidad del Rosario, Carrera 24 # 63C-69, Bogotá, Colombia.
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Spillman NJ, Beck JR, Goldberg DE. Protein export into malaria parasite-infected erythrocytes: mechanisms and functional consequences. Annu Rev Biochem 2015; 84:813-41. [PMID: 25621510 DOI: 10.1146/annurev-biochem-060614-034157] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Phylum Apicomplexa comprises a large group of obligate intracellular parasites of high medical and veterinary importance. These organisms succeed intracellularly by effecting remarkable changes in a broad range of diverse host cells. The transformation of the host erythrocyte is particularly striking in the case of the malaria parasite Plasmodium falciparum. P. falciparum exports hundreds of proteins that mediate a complex cellular renovation marked by changes in the permeability, rigidity, and cytoadherence properties of the host erythrocyte. The past decade has seen enormous progress in understanding the identity and function of these exported effectors, as well as the mechanisms by which they are trafficked into the host cell. Here we review these advances, place them in the context of host manipulation by related apicomplexans, and propose key directions for future research.
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Abstract
Host cell invasion by Toxoplasma gondii and other apicomplexan parasites requires transmembrane adhesins that mediate binding to receptors on the substrate and host cell to facilitate motility and invasion. Rhomboid proteases (ROMs) are thought to cleave adhesins within their transmembrane segments, thus allowing the parasite to disengage from receptors and completely enter the host cell. To examine the specific roles of individual ROMs during invasion, we generated single, double, and triple knockouts for the three ROMs expressed in T. gondii tachyzoites. Analysis of these mutants demonstrated that ROM4 is the primary protease involved in adhesin processing and host cell invasion, whereas ROM1 or ROM5 plays negligible roles in these processes. Deletion of ROM4 blocked the shedding of adhesins such as MIC2 (microneme protein 2), causing them to accumulate on the surface of extracellular parasites. Increased surface adhesins led to nonproductive attachment, altered gliding motility, impaired moving junction formation, and reduced invasion efficiency. Despite the importance of ROM4 for efficient invasion, mutants lacking all three ROMs were viable and MIC2 was still efficiently removed from the surface of invaded mutant parasites, implying the existence of ROM-independent mechanisms for adhesin removal during invasion. Collectively, these results suggest that although ROM processing of adhesins is not absolutely essential, it is important for efficient host cell invasion by T. gondii. Apicomplexan parasites such as Toxoplasma gondii express surface proteins that bind host cell receptors to aid invasion. Many of these adhesins are subject to cleavage by rhomboid proteases (ROMs) within their transmembrane segments during invasion. Previous studies have demonstrated the importance of adhesin cleavage for parasite invasion and proposed that the ROMs responsible for processing would be essential for parasite survival. In T. gondii, ROM5 was thought to be the critical ROM for adhesin shedding due to its robust protease activity in vitro and posterior localization on the parasite surface. Here, we knocked out all three ROMs in T. gondii tachyzoites and found that ROM4, but not ROM5, was key for adhesin cleavage. However, none of the ROMs individually or in combination was essential for cell entry, further emphasizing that essential pathways such as invasion typically rely on redundant pathways to ensure survival.
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Risco-Castillo V, Topçu S, Son O, Briquet S, Manzoni G, Silvie O. CD81 is required for rhoptry discharge during host cell invasion by Plasmodium yoelii sporozoites. Cell Microbiol 2014; 16:1533-48. [PMID: 24798694 DOI: 10.1111/cmi.12309] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 04/03/2014] [Accepted: 04/29/2014] [Indexed: 11/30/2022]
Abstract
Plasmodium sporozoites are transmitted by Anopheles mosquitoes and first infect the liver of their mammalian host, where they develop as liver stages before the onset of erythrocytic infection and malaria symptoms. Sporozoite entry into hepatocytes is an attractive target for anti-malarial prophylactic strategies but remains poorly understood at the molecular level. Apicomplexan parasites invade host cells by forming a parasitophorous vacuole that is essential for parasite development, a process that involves secretion of apical organelles called rhoptries. We previously reported that the host membrane protein CD81 is required for infection by Plasmodium falciparum and Plasmodium yoelii sporozoites. CD81 acts at an early stage of infection, possibly at the entry step, but the mechanisms involved are still unknown. To investigate the role of CD81 during sporozoite entry, we generated transgenic P. yoelii parasites expressing fluorescent versions of three known rhoptry proteins, RON2, RON4 and RAP2/3. We observed that RON2 and RON4 are lost following rhoptry discharge during merozoite and sporozoite entry. In contrast, our data indicate that RAP2/3 is secreted into the parasitophorous vacuole during infection. We further show that sporozoite rhoptry discharge occurs only in the presence of CD81, providing the first direct evidence for a role of CD81 during sporozoite productive invasion.
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Affiliation(s)
- Veronica Risco-Castillo
- Sorbonne Universités, UPMC Univ Paris 06, UMRS CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris), F-75013, Paris, France; INSERM, U1135, CIMI-Paris, F-75013, Paris, France; CNRS, ERL 8255, CIMI-Paris, F-75013, Paris, France
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Bargieri D, Lagal V, Andenmatten N, Tardieux I, Meissner M, Ménard R. Host cell invasion by apicomplexan parasites: the junction conundrum. PLoS Pathog 2014; 10:e1004273. [PMID: 25232721 PMCID: PMC4169498 DOI: 10.1371/journal.ppat.1004273] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Daniel Bargieri
- Institut Pasteur, Malaria Biology and Genetics Unit, Department of Parasitology and Mycology, Paris, France
| | - Vanessa Lagal
- Institut Cochin, Laboratory Barriers and Pathogens, INSERM U-1016, CNRS UMR-8104, University of Paris Descartes, Paris, France
| | - Nicole Andenmatten
- Institute of Infection, Immunity and Inflammation, Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
| | - Isabelle Tardieux
- Institut Cochin, Laboratory Barriers and Pathogens, INSERM U-1016, CNRS UMR-8104, University of Paris Descartes, Paris, France
| | - Markus Meissner
- Institute of Infection, Immunity and Inflammation, Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, United Kingdom
| | - Robert Ménard
- Institut Pasteur, Malaria Biology and Genetics Unit, Department of Parasitology and Mycology, Paris, France
- * E-mail:
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Tonkin ML, Crawford J, Lebrun ML, Boulanger MJ. Babesia divergens and Neospora caninum apical membrane antigen 1 structures reveal selectivity and plasticity in apicomplexan parasite host cell invasion. Protein Sci 2014; 22:114-27. [PMID: 23169033 DOI: 10.1002/pro.2193] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 10/02/2012] [Accepted: 10/05/2012] [Indexed: 11/09/2022]
Abstract
Host cell invasion by the obligate intracellular apicomplexan parasites, including Plasmodium (malaria) and Toxoplasma (toxoplasmosis), requires a step-wise mechanism unique among known host-pathogen interactions. A key step is the formation of the moving junction (MJ) complex, a circumferential constriction between the apical tip of the parasite and the host cell membrane that traverses in a posterior direction to enclose the parasite in a protective vacuole essential for intracellular survival. The leading model of MJ assembly proposes that Rhoptry Neck Protein 2 (RON2) is secreted into the host cell and integrated into the membrane where it serves as the receptor for apical membrane antigen 1 (AMA1) on the parasite surface. We have previously demonstrated that the AMA1-RON2 interaction is an effective target for inhibiting apicomplexan invasion. To better understand the AMA1-dependant molecular recognition events that promote invasion, including the significant AMA1-RON2 interaction, we present the structural characterization of AMA1 from the apicomplexan parasites Babesia divergens (BdAMA1) and Neospora caninum (NcAMA1) by X-ray crystallography. These studies offer intriguing structural insight into the RON2-binding surface groove in the AMA1 apical domain, which shows clear evidence for receptor-ligand co-evolution, and the hyper variability of the membrane proximal domain, which in Plasmodium is responsible for direct binding to erythrocytes. By incorporating the structural analysis of BdAMA1 and NcAMA1 with existing AMA1 structures and complexes we were able to define conserved pockets in the AMA1 apical groove that could be targeted for the design of broadly reactive therapeutics.
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Affiliation(s)
- Michelle L Tonkin
- Department of Biochemistry & Microbiology, University of Victoria, Victoria, British Columbia, V8W 3P6, Canada
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Bargieri DY, Andenmatten N, Lagal V, Thiberge S, Whitelaw JA, Tardieux I, Meissner M, Ménard R. Apical membrane antigen 1 mediates apicomplexan parasite attachment but is dispensable for host cell invasion. Nat Commun 2014; 4:2552. [PMID: 24108241 PMCID: PMC3826631 DOI: 10.1038/ncomms3552] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Accepted: 09/03/2013] [Indexed: 11/19/2022] Open
Abstract
Apicomplexan parasites invade host cells by forming a ring-like junction with the cell surface and actively sliding through the junction inside an intracellular vacuole. Apical membrane antigen 1 is conserved in apicomplexans and a long-standing malaria vaccine candidate. It is considered to have multiple important roles during host cell penetration, primarily in structuring the junction by interacting with the rhoptry neck 2 protein and transducing the force generated by the parasite motor during internalization. Here, we generate Plasmodium sporozoites and merozoites and Toxoplasma tachyzoites lacking apical membrane antigen 1, and find that the latter two are impaired in host cell attachment but the three display normal host cell penetration through the junction. Therefore, apical membrane antigen 1, rather than an essential invasin, is a dispensable adhesin of apicomplexan zoites. These genetic data have implications on the use of apical membrane antigen 1 or the apical membrane antigen 1–rhoptry neck 2 interaction as targets of intervention strategies against malaria or other diseases caused by apicomplexans. Plasmodium and Toxoplasma apical membrane antigen 1 (AMA1) is believed to be actively involved in host cell invasion by these parasites. Bargieri et al. now demonstrate that although AMA1 facilitates adhesion, invasion can proceed in the absence of the protein.
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Affiliation(s)
- Daniel Y Bargieri
- 1] Institut Pasteur, Malaria Biology and Genetics Unit, Department of Parasitology and Mycology, 28 Rue du Dr Roux, Paris, France [2]
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Evolutionary repurposing of endosomal systems for apical organelle biogenesis in Toxoplasma gondii. Int J Parasitol 2014; 44:133-8. [DOI: 10.1016/j.ijpara.2013.10.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/09/2013] [Accepted: 10/10/2013] [Indexed: 12/20/2022]
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Okamoto N, Keeling PJ. The 3D structure of the apical complex and association with the flagellar apparatus revealed by serial TEM tomography in Psammosa pacifica, a distant relative of the Apicomplexa. PLoS One 2014; 9:e84653. [PMID: 24392150 PMCID: PMC3879320 DOI: 10.1371/journal.pone.0084653] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Accepted: 11/17/2013] [Indexed: 11/18/2022] Open
Abstract
The apical complex is one of the defining features of apicomplexan parasites, including the malaria parasite Plasmodium, where it mediates host penetration and invasion. The apical complex is also known in a few related lineages, including several non-parasitic heterotrophs, where it mediates feeding behaviour. The origin of the apical complex is unclear, and one reason for this is that in apicomplexans it exists in only part of the life cycle, and never simultaneously with other major cytoskeletal structures like flagella and basal bodies. Here, we used conventional TEM and serial TEM tomography to reconstruct the three dimensional structure of the apical complex in Psammosa pacifica, a predatory relative of apicomplexans and dinoflagellates that retains the archetype apical complex and the flagellar apparatus simultaneously. The P. pacifica apical complex is associated with the gullet and consists of the pseudoconoid, micronemes, and electron dense vesicles. The pseudoconoid is a convex sheet consisting of eight short microtubules, plus a band made up of microtubules that originate from the flagellar apparatus. The flagellar apparatus consists of three microtubular roots. One of the microtubular roots attached to the posterior basal body is connected to bypassing microtubular strands, which are themselves connected to the extension of the pseudoconoid. These complex connections where the apical complex is an extension of the flagellar apparatus, reflect the ancestral state of both, dating back to the common ancestor of apicaomplexans and dinoflagellates.
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Affiliation(s)
- Noriko Okamoto
- The Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | - Patrick J. Keeling
- The Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
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Walker DM, Oghumu S, Gupta G, McGwire BS, Drew ME, Satoskar AR. Mechanisms of cellular invasion by intracellular parasites. Cell Mol Life Sci 2013; 71:1245-63. [PMID: 24221133 DOI: 10.1007/s00018-013-1491-1] [Citation(s) in RCA: 107] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 10/04/2013] [Accepted: 10/07/2013] [Indexed: 12/22/2022]
Abstract
Numerous disease-causing parasites must invade host cells in order to prosper. Collectively, such pathogens are responsible for a staggering amount of human sickness and death throughout the world. Leishmaniasis, Chagas disease, toxoplasmosis, and malaria are neglected diseases and therefore are linked to socio-economical and geographical factors, affecting well-over half the world's population. Such obligate intracellular parasites have co-evolved with humans to establish a complexity of specific molecular parasite-host cell interactions, forming the basis of the parasite's cellular tropism. They make use of such interactions to invade host cells as a means to migrate through various tissues, to evade the host immune system, and to undergo intracellular replication. These cellular migration and invasion events are absolutely essential for the completion of the lifecycles of these parasites and lead to their for disease pathogenesis. This review is an overview of the molecular mechanisms of protozoan parasite invasion of host cells and discussion of therapeutic strategies, which could be developed by targeting these invasion pathways. Specifically, we focus on four species of protozoan parasites Leishmania, Trypanosoma cruzi, Plasmodium, and Toxoplasma, which are responsible for significant morbidity and mortality.
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Affiliation(s)
- Dawn M Walker
- Department of Microbial Infection and Immunity, Wexner Medical Center, The Ohio State University, Columbus, OH, 43210, USA
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