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Rico-San Román L, Amieva R, Regidor-Cerrillo J, García-Sánchez M, Collantes-Fernández E, Pastor-Fernández I, Saeij JPJ, Ortega-Mora LM, Horcajo P. NcGRA7 and NcROP40 Play a Role in the Virulence of Neospora caninum in a Pregnant Mouse Model. Pathogens 2022; 11:pathogens11090998. [PMID: 36145430 PMCID: PMC9506596 DOI: 10.3390/pathogens11090998] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/24/2022] [Accepted: 08/30/2022] [Indexed: 12/01/2022] Open
Abstract
The intraspecific variability among Neospora caninum isolates in their in vitro behaviour and in vivo virulence has been widely studied. In particular, transcriptomic and proteomic analyses have shown a higher expression/abundance of specific genes/proteins in high-virulence isolates. Consequently, the dense granule protein NcGRA7 and the rhoptry protein NcROP40 were proposed as potential virulence factors. The objective of this study was to characterize the role of these proteins using CRISPR/Cas9 knockout (KO) parasites in a well-established pregnant BALB/c mouse model of N. caninum infection at midgestation. The deletion of NcGRA7 and NcROP40 was associated with a reduction of virulence, as infected dams displayed milder clinical signs, lower parasite burdens in the brain, and reduced mortality rates compared to those infected with the wild-type parasite (Nc-Spain7). Specifically, those infected with the NcGRA7 KO parasites displayed significantly milder clinical signs and a lower brain parasite burden. The median survival time of the pups from dams infected with the two KO parasites was significantly increased, but differences in neonatal mortality rates were not detected. Overall, the present study indicates that the disruption of NcGRA7 considerably impairs virulence in mice, while the impact of NcROP40 deletion was more modest. Further research is needed to understand the role of these virulence factors during N. caninum infection.
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Affiliation(s)
- Laura Rico-San Román
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Rafael Amieva
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Javier Regidor-Cerrillo
- SALUVET-Innova S.L., Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Marta García-Sánchez
- SALUVET-Innova S.L., Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Esther Collantes-Fernández
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Iván Pastor-Fernández
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
| | - Jeroen P. J. Saeij
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - Luis Miguel Ortega-Mora
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
- Correspondence: (L.M.O.-M.); (P.H.); Tel.: +34-91-3944098 (P.H.)
| | - Pilar Horcajo
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
- Correspondence: (L.M.O.-M.); (P.H.); Tel.: +34-91-3944098 (P.H.)
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2
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Toxoplasma gondii association with host mitochondria requires key mitochondrial protein import machinery. Proc Natl Acad Sci U S A 2021; 118:2013336118. [PMID: 33723040 PMCID: PMC7999873 DOI: 10.1073/pnas.2013336118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Host mitochondrial association (HMA) is a well-known phenomenon during Toxoplasma gondii infection of the host cell. The T. gondii locus mitochondrial association factor 1 (MAF1) is required for HMA and MAF1 encodes distinct paralogs of secreted dense granule effector proteins, some of which mediate the HMA phenotype (MAF1b paralogs drive HMA; MAF1a paralogs do not). To identify host proteins required for MAF1b-mediated HMA, we performed unbiased, label-free quantitative proteomics on host cells infected with type II parasites expressing MAF1b, MAF1a, and an HMA-incompetent MAF1b mutant. Across these samples, we identified ∼1,360 MAF1-interacting proteins, but only 13 that were significantly and uniquely enriched in MAF1b pull-downs. The gene products include multiple mitochondria-associated proteins, including those that traffic to the mitochondrial outer membrane. Based on follow-up endoribonuclease-prepared short interfering RNA (esiRNA) experiments targeting these candidate MAF1b-targeted host factors, we determined that the mitochondrial receptor protein TOM70 and mitochondria-specific chaperone HSPA9 were essential mediators of HMA. Additionally, the enrichment of TOM70 at the parasitophorous vacuole membrane interface suggests parasite-driven sequestration of TOM70 by the parasite. These results show that the interface between the T. gondii vacuole and the host mitochondria is characterized by interactions between a single parasite effector and multiple target host proteins, some of which are critical for the HMA phenotype itself. The elucidation of the functional members of this complex will permit us to explain the link between HMA and changes in the biology of the host cell.
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3
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Xia J, Venkat A, Bainbridge RE, Reese ML, Le Roch KG, Ay F, Boyle JP. Third-generation sequencing revises the molecular karyotype for Toxoplasma gondii and identifies emerging copy number variants in sexual recombinants. Genome Res 2021; 31:834-851. [PMID: 33906962 PMCID: PMC8092015 DOI: 10.1101/gr.262816.120] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 02/03/2021] [Indexed: 12/28/2022]
Abstract
Toxoplasma gondii is a useful model for intracellular parasitism given its ease of culture in the laboratory and genomic resources. However, as for many other eukaryotes, the T. gondii genome contains hundreds of sequence gaps owing to repetitive and/or unclonable sequences that disrupt the assembly process. Here, we use the Oxford Nanopore Minion platform to generate near-complete de novo genome assemblies for multiple strains of T. gondii and its near relative, N. caninum. We significantly improved T. gondii genome contiguity (average N50 of ∼6.6 Mb) and added ∼2 Mb of newly assembled sequence. For all of the T. gondii strains that we sequenced (RH, ME49, CTG, II×III progeny clones CL13, S27, S21, S26, and D3X1), the largest contig ranged in size between 11.9 and 12.1 Mb in size, which is larger than any previously reported T. gondii chromosome, and found to be due to a consistent fusion of Chromosomes VIIb and VIII. These data were validated by mapping existing T. gondii ME49 Hi-C data to our assembly, providing parallel lines of evidence that the T. gondii karyotype consists of 13, rather than 14, chromosomes. By using this technology, we also resolved hundreds of tandem repeats of varying lengths, including in well-known host-targeting effector loci like rhoptry protein 5 (ROP5) and ROP38. Finally, when we compared T. gondii with N. caninum, we found that although the 13-chromosome karyotype was conserved, extensive, previously unappreciated chromosome-scale rearrangements had occurred in T. gondii and N. caninum since their most recent common ancestry.
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Affiliation(s)
- Jing Xia
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Aarthi Venkat
- Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut 06520, USA.,La Jolla Institute for Immunology, La Jolla, California 92037, USA
| | - Rachel E Bainbridge
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | | | - Karine G Le Roch
- Department of Molecular, Cell and Systems Biology, College of Agricultural and Life Sciences, University of California-Riverside, Riverside, California 92521, USA
| | - Ferhat Ay
- La Jolla Institute for Immunology, La Jolla, California 92037, USA.,School of Medicine, University of California-San Diego, La Jolla, California 92093, USA
| | - Jon P Boyle
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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4
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Abstract
Toxoplasma gondii causes a chronic infection that renders the immunocompromised human host susceptible to toxoplasmic encephalitis triggered by cyst reactivation in the central nervous system. The dense granule protein GRA12 is a major parasite virulence factor required for parasite survival during acute infection. Here, we characterized the role of four GRA12-related genes in acute and chronic stages of infection. While GRA12A, GRA12B, and GRA12D were highly expressed in asexual stage tachyzoites and bradyzoites, expression of GRA12C appeared to be restricted to the sexual stages. In contrast to deletion of GRA12 (Δgra12), no major defects in acute virulence were observed in Δgra12A, Δgra12B, or Δgra12D parasites, though Δgra12B parasites exhibited an increased tachyzoite replication rate. Bradyzoites secreted GRA12A, GRA12B, and GRA12D and incorporated these molecules into the developing cyst wall, as well as the cyst matrix in distinct patterns. Similar to GRA12, GRA12A, GRA12B, and GRA12D colocalized with the dense granules in extracellular tachyzoites, with GRA2 and the intravacuolar network in the tachyzoite stage parasitophorous vacuole and with GRA2 in the cyst matrix and cyst wall. Chronic stage cyst burdens were decreased in mice infected with Δgra12A parasites and were increased in mice infected with Δgra12B parasites. However, Δgra12B cysts were not efficiently maintained in vivo Δgra12A, Δgra12B, and Δgra12D in vitro cysts displayed a reduced reactivation efficiency, and reactivation of Δgra12A cysts was delayed. Collectively, our results suggest that a family of genes related to GRA12 play significant roles in the formation, maintenance, and reactivation of chronic stage cysts.IMPORTANCE If host immunity weakens, Toxoplasma gondii cysts recrudesce in the central nervous system and cause a severe toxoplasmic encephalitis. Current therapies target acute stage infection but do not eliminate chronic cysts. Parasite molecules that mediate the development and persistence of chronic infection are poorly characterized. Dense granule (GRA) proteins such as GRA12 are key virulence factors during acute infection. Here, we investigated four GRA12-related genes. GRA12-related genes were not major virulence factors during acute infection. Instead, GRA12-related proteins localized at the cyst wall and cyst matrix and played significant roles in cyst development, persistence, and reactivation during chronic infection. Similar to GRA12, the GRA12-related proteins selectively associated with the intravacuolar network of membranes inside the vacuole. Collectively, our results support the hypothesis that GRA12 proteins associated with the intravacuolar membrane system support parasite virulence during acute infection and cyst development, persistence, and reactivation during chronic infection.
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5
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Sokol-Borrelli SL, Coombs RS, Boyle JP. A Comparison of Stage Conversion in the Coccidian Apicomplexans Toxoplasma gondii, Hammondia hammondi, and Neospora caninum. Front Cell Infect Microbiol 2020; 10:608283. [PMID: 33344268 PMCID: PMC7744739 DOI: 10.3389/fcimb.2020.608283] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 11/06/2020] [Indexed: 01/31/2023] Open
Abstract
Stage conversion is a critical life cycle feature for several Apicomplexan parasites as the ability to switch between life forms is critical for replication, dissemination, pathogenesis and ultimately, transmission to a new host. In order for these developmental transitions to occur, the parasite must first sense changes in their environment, such as the presence of stressors or other environmental signals, and then respond to these signals by initiating global alterations in gene expression. As our understanding of the genetic components required for stage conversion continues to broaden, we can better understand the conserved mechanisms for this process and unique components and their contribution to pathogenesis by comparing stage conversion in multiple closely related species. In this review, we will discuss what is currently known about the mechanisms driving stage conversion in Toxoplasma gondii and its closest relatives Hammondia hammondi and Neospora caninum. Work by us and others has shown that these species have some important differences in the way that they (1) progress through their life cycle and (2) respond to stage conversion initiating stressors. To provide a specific example of species-specific complexities associated with stage conversion, we will discuss our recent published and unpublished work comparing stress responses in T. gondii and H. hammondi.
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Affiliation(s)
| | | | - Jon P. Boyle
- University of Pittsburgh, Department of Biological Sciences, Kenneth P. Dietrich School of Arts and Sciences, Pittsburgh, PA, United States
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6
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Calarco L, Ellis J. Species diversity and genome evolution of the pathogenic protozoan parasite, Neospora caninum. INFECTION GENETICS AND EVOLUTION 2020; 84:104444. [PMID: 32619639 DOI: 10.1016/j.meegid.2020.104444] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 04/16/2020] [Accepted: 06/23/2020] [Indexed: 01/04/2023]
Abstract
Neospora caninum is a cyst-forming coccidian parasite of veterinary and economical significance, affecting dairy and beef cattle industries on a global scale. Comparative studies suggest that N. caninum consists of a globally dispersed, diverse population of lineages, distinguished by their geographical origin, broad host range, and phenotypic features. This viewpoint is however changing. While intraspecies diversity, and more specifically pathogenic variability, has been experimentally demonstrated in a myriad of studies, the underlying contributors and sources responsible for such diversity have remained nebulous. However, recent large-scale sequence and bioinformatics studies have aided in revealing intrinsic genetic differences distinguishing isolates of this species, that await further characterisation as causative links to virulence and pathogenicity. Furthermore, progress on N. caninum research as a non-model organism is hindered by a lack of robust, annotated genomic, transcriptomic, and proteomic data for the species, especially compared to other thoroughly studied Apicomplexa such as Toxoplasma gondii and Plasmodium species. This review explores the current body of knowledge on intra-species diversity within N. caninum. This includes the contribution of sequence variants in both coding and non-coding regions, the presence of genome polymorphic hotspots, and the identification of non-synonymous mutations. The implications of such diversity on important parasite phenotypes such as pathogenicity and population structure are also discussed. Lastly, the identification of potential virulence factors from both in-silico and next generation sequencing studies is examined, offering new insights into potential avenues for future research on neosporosis.
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Affiliation(s)
- Larissa Calarco
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia.
| | - John Ellis
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW 2007, Australia
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7
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Wong ZS, Borrelli SLS, Coyne CC, Boyle JP. Cell type- and species-specific host responses to Toxoplasma gondii and its near relatives. Int J Parasitol 2020; 50:423-431. [PMID: 32407716 PMCID: PMC8281328 DOI: 10.1016/j.ijpara.2020.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 03/30/2020] [Accepted: 04/03/2020] [Indexed: 10/24/2022]
Abstract
Toxoplasma gondii is remarkably unique in its ability to successfully infect vertebrate hosts from multiple phyla and can successfully infect most cells within these organisms. The infection outcome in each of these species is determined by the complex interaction between parasite and host genotype. As techniques to quantify global changes in cell function become more readily available and precise, new data are coming to light about how (i) different host cell types respond to parasitic infection and (ii) different parasite species impact the host. Here we focus on recent studies comparing the response to intracellular parasitism by different cell types and insights into understanding host-parasite interactions from comparative studies on T. gondii and its close extant relatives.
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Affiliation(s)
- Zhee S Wong
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, United States
| | - Sarah L Sokol Borrelli
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, United States
| | - Carolyn C Coyne
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Jon P Boyle
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, United States.
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8
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Coombs RS, Blank ML, English ED, Adomako-Ankomah Y, Urama ICS, Martin AT, Yarovinsky F, Boyle JP. Immediate Interferon Gamma Induction Determines Murine Host Compatibility Differences between Toxoplasma gondii and Neospora caninum. Infect Immun 2020; 88:e00027-20. [PMID: 32014892 PMCID: PMC7093116 DOI: 10.1128/iai.00027-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 01/13/2020] [Indexed: 12/24/2022] Open
Abstract
Rodents are critical for the transmission of Toxoplasma gondii to the definitive feline host via predation, and this relationship has been extensively studied as a model for immune responses to parasites. Neospora caninum is a closely related coccidian parasite of ruminants and canines but is not naturally transmitted by rodents. We compared mouse innate immune responses to N. caninum and T. gondii and found marked differences in cytokine levels and parasite growth kinetics during the first 24 h postinfection (hpi). N. caninum-infected mice produced significantly higher levels of interleukin-12 (IL-12) and interferon gamma (IFN-γ) by as early as 4 hpi, but the level of IFN-γ was significantly lower or undetectable in T. gondii-infected mice during the first 24 hpi. "Immediate" IFN-γ and IL-12p40 production was not detected in MyD88-/- mice. However, unlike IL-12p40-/- and IFN-γ-/- mice, MyD88-/- mice survived N. caninum infections at the dose used in this study. Serial measures of parasite burden showed that MyD88-/- mice were more susceptible to N. caninum infections than wild-type (WT) mice, and control of parasite burdens correlated with a pulse of serum IFN-γ at 3 to 4 days postinfection in the absence of detectable IL-12. Immediate IFN-γ was partially dependent on the T. gondii mouse profilin receptor Toll-like receptor 11 (TLR11), but the ectopic expression of N. caninum profilin in T. gondii had no impact on early IFN-γ production or parasite proliferation. Our data indicate that T. gondii is capable of evading host detection during the first hours after infection, while N. caninum is not, and this is likely due to the early MyD88-dependent recognition of ligands other than profilin.
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Affiliation(s)
- Rachel S Coombs
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Matthew L Blank
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Elizabeth D English
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Yaw Adomako-Ankomah
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | | | - Andrew T Martin
- Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester, Rochester, New York, USA
| | - Felix Yarovinsky
- Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester, Rochester, New York, USA
| | - Jon P Boyle
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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9
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García-Sánchez M, Jiménez-Pelayo L, Horcajo P, Regidor-Cerrillo J, Collantes-Fernández E, Ortega-Mora LM. Gene Expression Profiling of Neospora caninum in Bovine Macrophages Reveals Differences Between Isolates Associated With Key Parasite Functions. Front Cell Infect Microbiol 2019; 9:354. [PMID: 31681630 PMCID: PMC6803445 DOI: 10.3389/fcimb.2019.00354] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 10/01/2019] [Indexed: 12/19/2022] Open
Abstract
Intraspecific differences in biological traits between Neospora caninum isolates have been widely described and associated with variations in virulence. However, the molecular basis underlying these differences has been poorly studied. We demonstrated previously that Nc-Spain7 and Nc-Spain1H, high- and low-virulence isolates, respectively, show different invasion, proliferation and survival capabilities in bovine macrophages (boMØs), a key cell in the immune response against Neospora, and modulate the cell immune response in different ways. Here, we demonstrate that these differences are related to specific tachyzoite gene expression profiles. Specifically, the low-virulence Nc-Spain1H isolate showed enhanced expression of genes encoding for surface antigens and genes related to the bradyzoite stage. Among the primary up-regulated genes in Nc-Spain7, genes involved in parasite growth and redox homeostasis are particularly noteworthy because of their correlation with the enhanced proliferation and survival rates of Nc-Spain7 in boMØs relative to Nc-Spain1H. Genes potentially implicated in induction of proinflammatory immune responses were found to be up-regulated in the low-virulence isolate, whereas the high-virulence isolate showed enhanced expression of genes that may be involved in immune evasion. These results represent a further step in understanding the parasite effector molecules that may be associated to virulence and thus to disease traits as abortion and transmission.
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Affiliation(s)
- Marta García-Sánchez
- Saluvet, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | - Laura Jiménez-Pelayo
- Saluvet, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | - Pilar Horcajo
- Saluvet, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | - Javier Regidor-Cerrillo
- Saluvet, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain.,Saluvet-Innova, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | - Esther Collantes-Fernández
- Saluvet, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
| | - Luis Miguel Ortega-Mora
- Saluvet, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Madrid, Spain
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10
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Effector variation at tandem gene arrays in tissue-dwelling coccidia: who needs antigenic variation anyway? Curr Opin Microbiol 2018; 46:86-92. [PMID: 30317151 DOI: 10.1016/j.mib.2018.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 08/28/2018] [Accepted: 09/24/2018] [Indexed: 11/20/2022]
Abstract
Locus expansion and diversification is pervasive in apicomplexan genomes and is predominantly found in loci encoding secreted proteins that interact with factors outside of the parasite. Key for understanding the impact of each of these loci on the host requires identification and functional characterization of their protein products, but these repetitive loci often are refractory to genome assembly. In this review we focus on Toxoplasma gondii and its nearest relatives to highlight the known impact of duplicated and diversified loci on our understanding of the host-pathogen molecular arms race. We describe current tools used for the identification and characterization of these loci, and review the most recent examples of how gene-expansion driven diversification can lead to novel gene functions.
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11
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Blank ML, Parker ML, Ramaswamy R, Powell CJ, English ED, Adomako-Ankomah Y, Pernas LF, Workman SD, Boothroyd JC, Boulanger MJ, Boyle JP. A Toxoplasma gondii locus required for the direct manipulation of host mitochondria has maintained multiple ancestral functions. Mol Microbiol 2018; 108:519-535. [PMID: 29505111 PMCID: PMC6245547 DOI: 10.1111/mmi.13947] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2018] [Indexed: 01/16/2023]
Abstract
The Toxoplasma gondii locus mitochondrial association factor 1 (MAF1) encodes multiple paralogs, some of which mediate host mitochondrial association (HMA). Previous work showed that HMA was a trait that arose in T. gondii through neofunctionalization of an ancestral MAF1 ortholog. Structural analysis of HMA-competent and incompetent MAF1 paralogs (MAF1b and MAF1a, respectively) revealed that both paralogs harbor an ADP ribose binding macro-domain, with comparatively low (micromolar) affinity for ADP ribose. Replacing the 16 C-terminal residues of MAF1b with those of MAF1a abrogated HMA, and we also show that only three residues in the C-terminal helix are required for MAF1-mediated HMA. Importantly these same three residues are also required for the in vivo growth advantage conferred by MAF1b, providing a definitive link between in vivo proliferation and manipulation of host mitochondria. Co-immunoprecipitation assays reveal that the ability to interact with the mitochondrial MICOS complex is shared by HMA-competent and incompetent MAF1 paralogs and mutants. The weak ADPr coordination and ability to interact with the MICOS complex shared between divergent paralogs may represent modular ancestral functions for this tandemly expanded and diversified T. gondii locus.
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Affiliation(s)
- Matthew L. Blank
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Michelle L. Parker
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Raghavendran Ramaswamy
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Cameron J. Powell
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Elizabeth D. English
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Yaw Adomako-Ankomah
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Lena F. Pernas
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Sean D. Workman
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - John C. Boothroyd
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Martin J. Boulanger
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Jon P. Boyle
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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12
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Integrative transcriptome and proteome analyses define marked differences between Neospora caninum isolates throughout the tachyzoite lytic cycle. J Proteomics 2017; 180:108-119. [PMID: 29154927 DOI: 10.1016/j.jprot.2017.11.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 10/25/2017] [Accepted: 11/09/2017] [Indexed: 11/22/2022]
Abstract
Neospora caninum is one of the main causes of transmissible abortion in cattle. Intraspecific variations in virulence have been widely shown among N. caninum isolates. However, the molecular basis governing such variability have not been elucidated to date. In this study label free LC-MS/MS was used to investigate proteome differences between the high virulence isolate Nc-Spain7 and the low virulence isolate Nc-Spain1H throughout the tachyzoite lytic cycle. The results showed greater differences in the abundance of proteins at invasion and egress with 77 and 62 proteins, respectively. During parasite replication, only 19 proteins were differentially abundant between isolates. The microneme protein repertoire involved in parasite invasion and egress was more abundant in the Nc-Spain1H isolate, which displays a lower invasion rate. Rhoptry and dense granule proteins, proteins related to metabolism and stress responses also showed differential abundances between isolates. Comparative RNA-Seq analyses during tachyzoite egress were also performed, revealing an expression profile of genes associated with the bradyzoite stage in the low virulence Nc-Spain1H isolate. The differences in proteome and RNA expression profiles between these two isolates reveal interesting insights into likely mechanisms involved in specific phenotypic traits and virulence in N. caninum. SIGNIFICANCE The molecular basis that governs biological variability in N. caninum and the pathogenesis of neosporosis has not been well-established yet. This is the first study in which high throughput technology of LC-MS/MS and RNA-Seq is used to investigate differences in the proteome and transcriptome between two well-characterized isolates. Both isolates displayed different proteomes throughout the lytic cycle and the transcriptomes also showed marked variations but were inconsistent with the proteome results. However, both datasets identified a pre-bradyzoite status of the low virulence isolate Nc-Spain1H. This study reveals interesting insights into likely mechanisms involved in virulence in N. caninum and shed light on a subset of proteins that are potentially involved in the pathogenesis of this parasite.
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Pastor-Fernández I, Regidor-Cerrillo J, Álvarez-García G, Marugán-Hernández V, García-Lunar P, Hemphill A, Ortega-Mora LM. The tandemly repeated NTPase (NTPDase) from Neospora caninum is a canonical dense granule protein whose RNA expression, protein secretion and phosphorylation coincides with the tachyzoite egress. Parasit Vectors 2016; 9:352. [PMID: 27329357 PMCID: PMC4915099 DOI: 10.1186/s13071-016-1620-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 06/01/2016] [Indexed: 12/26/2022] Open
Abstract
Background NTPases (also NTPDases) are enzymes with apyrase activity. They are widely distributed among eukaryotes, and also among members of the family Sarcocystidae. In Toxoplasma gondii, the TgNTPase accumulates in the dense granules, and has been commonly associated with the strain virulence. In the closely related Neospora caninum, the NcNTPase lacks nucleoside diphosphate hydrolase activity and appears to be more abundant in virulent isolates, indicating that it may contribute to the pathogenicity of neosporosis. However, so far no additional information on NcNTPase has been provided. Methods Herein, the NcNTPase coding sequences were analysed by different in silico and de novo sequencing approaches. A comparative analysis of NcNTPase and NcGRA7 in terms of protein dynamics, secretion, phosphorylation, and mRNA expression profiles during the tachyzoite lytic cycle was also carried out. Moreover, NcNTPase immunolocalization was analysed by confocal microscopy techniques over a set number of time-points. Results We describe the presence of three different loci containing three copies of the NcNTPase within the Nc-Liv genome, and report the existence of up to four different NcNTPase alleles in Nc-Liv. We also provide evidence for the occurrence of diverse protein species of the NcNTPase by two-dimensional gel electrophoresis. Both NcNTPase and NcGRA7 were similarly up-regulated and secreted during the egress and/or early invasion phases, and were phosphorylated. However, its secretion was not affected by the addition of calcium modulators such as A23187 and ethanol. NcNTPase and NcGRA7 localized in dense granules and parasitophorous vacuole membrane throughout the lytic cycle, although differed in their inmunolocalization during early invasion and egress. Conclusions The present study reveals the complexity of the NcNTPase loci in N. caninum. We hypothesize that the expression of different isoforms of the NcNTPase protein could contribute to parasite virulence. Our findings showed regulation of expression, secretion and phosphorylation of NcNTPase suggesting a potential role for progression through the tachyzoites lytic cycle. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1620-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Iván Pastor-Fernández
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Javier Regidor-Cerrillo
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Gema Álvarez-García
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Virginia Marugán-Hernández
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Paula García-Lunar
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Andrew Hemphill
- Institute of Parasitology, Vetsuisse Faculty, University of Berne, Länggass-Strasse 122, CH-3012, Berne, Switzerland
| | - Luis M Ortega-Mora
- SALUVET, Animal Health Department, Faculty of Veterinary Sciences, Complutense University of Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain.
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Host Mitochondrial Association Evolved in the Human Parasite Toxoplasma gondii via Neofunctionalization of a Gene Duplicate. Genetics 2016; 203:283-98. [PMID: 26920761 PMCID: PMC4858780 DOI: 10.1534/genetics.115.186270] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/14/2016] [Indexed: 01/30/2023] Open
Abstract
In Toxoplasma gondii, an intracellular parasite of humans and other animals, host mitochondrial association (HMA) is driven by a gene family that encodes multiple mitochondrial association factor 1 (MAF1) proteins. However, the importance of MAF1 gene duplication in the evolution of HMA is not understood, nor is the impact of HMA on parasite biology. Here we used within- and between-species comparative analysis to determine that the MAF1 locus is duplicated in T. gondii and its nearest extant relative Hammondia hammondi, but not another close relative, Neospora caninum. Using cross-species complementation, we determined that the MAF1 locus harbors multiple distinct paralogs that differ in their ability to mediate HMA, and that only T. gondii and H. hammondi harbor HMA+ paralogs. Additionally, we found that exogenous expression of an HMA+ paralog in T. gondii strains that do not normally exhibit HMA provides a competitive advantage over their wild-type counterparts during a mouse infection. These data indicate that HMA likely evolved by neofunctionalization of a duplicate MAF1 copy in the common ancestor of T. gondii and H. hammondi, and that the neofunctionalized gene duplicate is selectively advantageous.
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Local admixture of amplified and diversified secreted pathogenesis determinants shapes mosaic Toxoplasma gondii genomes. Nat Commun 2016; 7:10147. [PMID: 26738725 PMCID: PMC4729833 DOI: 10.1038/ncomms10147] [Citation(s) in RCA: 178] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 11/09/2015] [Indexed: 01/22/2023] Open
Abstract
Toxoplasma gondii is among the most prevalent parasites worldwide, infecting many wild and domestic animals and causing zoonotic infections in humans. T. gondii differs substantially in its broad distribution from closely related parasites that typically have narrow, specialized host ranges. To elucidate the genetic basis for these differences, we compared the genomes of 62 globally distributed T. gondii isolates to several closely related coccidian parasites. Our findings reveal that tandem amplification and diversification of secretory pathogenesis determinants is the primary feature that distinguishes the closely related genomes of these biologically diverse parasites. We further show that the unusual population structure of T. gondii is characterized by clade-specific inheritance of large conserved haploblocks that are significantly enriched in tandemly clustered secretory pathogenesis determinants. The shared inheritance of these conserved haploblocks, which show a different ancestry than the genome as a whole, may thus influence transmission, host range and pathogenicity.
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English ED, Adomako-Ankomah Y, Boyle JP. Secreted effectors in Toxoplasma gondii and related species: determinants of host range and pathogenesis? Parasite Immunol 2015; 37:127-40. [PMID: 25655311 PMCID: PMC4359005 DOI: 10.1111/pim.12166] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 11/26/2014] [Indexed: 12/20/2022]
Abstract
Recent years have witnessed the discovery of a number of secreted proteins in Toxoplasma gondii that play important roles in host-pathogen interactions and parasite virulence, particularly in the mouse model. However, the role that these proteins play in driving the unique features of T. gondii compared to some of its nearest apicomplexan relatives (Hammondia hammondi and Neospora caninum) is unknown. These unique features include distinct dissemination characteristics in vivo and a vast host range. In this review we comprehensively survey what is known about disease outcome, the host response and host range for T. gondii, H. hammondi, and N. caninum. We then review what is presently known about recently identified secreted virulence effectors in these three genetically related, but phenotypically distinct, species. Finally we exploit the existence of genome sequences for these three organisms and discuss what is known about the presence, and functionality, of key T. gondii effectors in these three species.
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Affiliation(s)
- E D English
- Department of Biological Sciences, Dietrich School of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA, USA
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Toxoplasma gondii superinfection and virulence during secondary infection correlate with the exact ROP5/ROP18 allelic combination. mBio 2015; 6:e02280. [PMID: 25714710 PMCID: PMC4358003 DOI: 10.1128/mbio.02280-14] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The intracellular parasite Toxoplasma gondii infects a wide variety of vertebrate species globally. Infection in most hosts causes a lifelong chronic infection and generates immunological memory responses that protect the host against new infections. In regions where the organism is endemic, multiple exposures to T. gondii likely occur with great frequency, yet little is known about the interaction between a chronically infected host and the parasite strains from these areas. A widely used model to explore secondary infection entails challenge of chronically infected or vaccinated mice with the highly virulent type I RH strain. Here, we show that although vaccinated or chronically infected C57BL/6 mice are protected against the type I RH strain, they are not protected against challenge with most strains prevalent in South America or another type I strain, GT1. Genetic and genomic analyses implicated the parasite-secreted rhoptry effectors ROP5 and ROP18, which antagonize the host’s gamma interferon-induced immunity-regulated GTPases (IRGs), as primary requirements for virulence during secondary infection. ROP5 and ROP18 promoted parasite superinfection in the brains of challenged survivors. We hypothesize that superinfection may be an important mechanism to generate T. gondii strain diversity, simply because two parasite strains would be present in a single meal consumed by the feline definitive host. Superinfection may drive the genetic diversity of Toxoplasma strains in South America, where most isolates are IRG resistant, compared to North America, where most strains are IRG susceptible and are derived from a few clonal lineages. In summary, ROP5 and ROP18 promote Toxoplasma virulence during reinfection. Toxoplasma gondii is a widespread parasite of warm-blooded animals and currently infects one-third of the human population. A long-standing assumption in the field is that prior exposure to this parasite protects the host from subsequent reexposure, due to the generation of protective immunological memory. However, this assumption is based on clinical data and mouse models that analyze infections with strains common to Europe and North America. In contrast, we found that the majority of strains sampled from around the world, in particular those from South America, were able to kill or reinfect the brains of hosts previously exposed to T. gondii. The T. gondii virulence factors ROP5 and ROP18, which inhibit key host effectors that mediate parasite killing, were required for these phenotypes. We speculate that these results underpin clinical observations that pregnant women previously exposed to Toxoplasma can develop congenital infection upon reexposure to South American strains.
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