201
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Das A, Chai JC, Kim SH, Lee YS, Park KS, Jung KH, Chai YG. Transcriptome sequencing of microglial cells stimulated with TLR3 and TLR4 ligands. BMC Genomics 2015; 16:517. [PMID: 26159724 PMCID: PMC4497376 DOI: 10.1186/s12864-015-1728-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 06/26/2015] [Indexed: 01/07/2023] Open
Abstract
Background Resident macrophages in the CNS microglia become activated and produce proinflammatory molecules upon encountering bacteria or viruses. TLRs are a phylogenetically conserved diverse family of sensors that drive innate immune responses following interactions with PAMPs. TLR3 and TLR4 recognize viral dsRNA Poly (I:C) and bacterial endotoxin LPS, respectively. Importantly, these receptors differ in their downstream adaptor molecules. Thus far, only a few studies have investigated the effects of TLR3 and TLR4 in macrophages. However, a genome-wide search for the effects of these TLRs has not been performed in microglia using RNA-seq. Gene expression patterns were determined for the BV-2 microglial cell line when stimulated with viral dsRNA Poly (I:C) or bacterial endotoxin LPS to identify novel transcribed genes, as well as investigate how differences in downstream signaling could influence gene expression in innate immunity. Results Sequencing assessment and quality evaluation revealed that common and unique patterns of proinflammatory genes were significantly up-regulated in response to TLR3 and TLR4 stimulation. However, the IFN/viral response gene showed a stronger response to TLR3 stimulation than to TLR4 stimulation. Unexpectedly, TLR3 and TLR4 stimulation did not activate IFN-ß and IRF3 in BV-2 microglia. Most importantly, we observed that previously unidentified transcription factors (TFs) (i.e., IRF1, IRF7, and IRF9) and the epigenetic regulators KDM4A and DNMT3L were significantly up-regulated in both TLR3- and TLR4-stimulated microglia. We also identified 29 previously unidentified genes that are important in immune regulation. In addition, we confirmed the expressions of key inflammatory genes as well as pro-inflammatory mediators in the supernatants were significantly induced in TLR3-and TLR4-stimulated primary microglial cells. Moreover, transcriptional start sites (TSSs) and isoforms, as well as differential promoter usage, revealed a complex pattern of transcriptional and post-transcriptional gene regulation upon infection with TLR3 and TLR4. Furthermore, TF motif analysis (-950 to +50 bp of the 5′ upstream promoters) revealed that the DNA sequences for NF-κB, IRF1, and STAT1 were significantly enriched in TLR3- and TLR4-stimulated microglia. Conclusions These unprecedented findings not only permit a comparison of TLR3-and TLR4-stimulated genes but also identify new genes that have not been previously implicated in innate immunity. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1728-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Amitabh Das
- Department of Bionanotechnology, Hanyang University, Seoul, 133-791, Republic of Korea.
| | - Jin Choul Chai
- Department of Molecular & Life Sciences, Hanyang University, Ansan, 426-791, Republic of Korea.
| | - Sun Hwa Kim
- Department of Molecular & Life Sciences, Hanyang University, Ansan, 426-791, Republic of Korea.
| | - Young Seek Lee
- Department of Molecular & Life Sciences, Hanyang University, Ansan, 426-791, Republic of Korea.
| | - Kyoung Sun Park
- Department of Molecular & Life Sciences, Hanyang University, Ansan, 426-791, Republic of Korea.
| | - Kyoung Hwa Jung
- Department of Molecular & Life Sciences, Hanyang University, Ansan, 426-791, Republic of Korea. .,Institute of Natural Science & Technology, Hanyang University, Ansan, 426-791, South Korea.
| | - Young Gyu Chai
- Department of Bionanotechnology, Hanyang University, Seoul, 133-791, Republic of Korea. .,Department of Molecular & Life Sciences, Hanyang University, Ansan, 426-791, Republic of Korea.
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202
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Ning HR, Huang SY, Wang JL, Xu QM, Zhu XQ. Genetic Diversity of Toxoplasma gondii Strains from Different Hosts and Geographical Regions by Sequence Analysis of GRA20 Gene. THE KOREAN JOURNAL OF PARASITOLOGY 2015; 53:345-8. [PMID: 26174830 PMCID: PMC4510676 DOI: 10.3347/kjp.2015.53.3.345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 04/05/2015] [Accepted: 04/12/2015] [Indexed: 11/28/2022]
Abstract
Toxoplasma gondii is a eukaryotic parasite of the phylum Apicomplexa, which infects all warm-blood animals, including humans. In the present study, we examined sequence variation in dense granule 20 (GRA20) genes among T. gondii isolates collected from different hosts and geographical regions worldwide. The complete GRA20 genes were amplified from 16 T. gondii isolates using PCR, sequence were analyzed, and phylogenetic reconstruction was analyzed by maximum parsimony (MP) and maximum likelihood (ML) methods. The results showed that the complete GRA20 gene sequence was 1,586 bp in length among all the isolates used in this study, and the sequence variations in nucleotides were 0-7.9% among all strains. However, removing the type III strains (CTG, VEG), the sequence variations became very low, only 0-0.7%. These results indicated that the GRA20 sequence in type III was more divergence. Phylogenetic analysis of GRA20 sequences using MP and ML methods can differentiate 2 major clonal lineage types (type I and type III) into their respective clusters, indicating the GRA20 gene may represent a novel genetic marker for intraspecific phylogenetic analyses of T. gondii.
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Affiliation(s)
- Hong-Rui Ning
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui Province 230036, PR China ; State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China
| | - Si-Yang Huang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China
| | - Jin-Lei Wang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China
| | - Qian-Ming Xu
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui Province 230036, PR China
| | - Xing-Quan Zhu
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui Province 230036, PR China ; State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China
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203
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Besteiro S. Toxoplasma control of host apoptosis: the art of not biting too hard the hand that feeds you. MICROBIAL CELL 2015; 2:178-181. [PMID: 28362004 PMCID: PMC5349139 DOI: 10.15698/mic2015.06.209] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Sébastien Besteiro
- DIMNP, UMR 5235 CNRS, Université de Montpellier, 34095 Montpellier, France
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204
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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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205
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Graumann K, Schaumburg F, Reubold TF, Hippe D, Eschenburg S, Lüder CGK. Toxoplasma gondii inhibits cytochrome c-induced caspase activation in its host cell by interference with holo-apoptosome assembly. MICROBIAL CELL 2015; 2:150-162. [PMID: 28357287 PMCID: PMC5349237 DOI: 10.15698/mic2015.05.201] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Inhibition of programmed cell death pathways of mammalian cells often facilitates the sustained survival of intracellular microorganisms. The apicomplexan parasite Toxoplasma gondii is a master regulator of host cell apoptotic pathways. Here, we have characterized a novel anti-apoptotic activity of T. gondii. Using a cell-free cytosolic extract model, we show that T. gondii interferes with the activities of caspase 9 and caspase 3/7 which have been induced by exogenous cytochrome c and dATP. Proteolytic cleavage of caspases 9 and 3 is also diminished suggesting inhibition of holo-apoptosome function. Parasite infection of Jurkat T cells and subsequent triggering of apoptosome formation by exogenous cytochrome cin vitro and in vivo indicated that T. gondii also interferes with caspase activation in infected cells. Importantly, parasite inhibition of cytochrome c-induced caspase activation considerably contributes to the overall anti-apoptotic activity of T. gondii as observed in staurosporine-treated cells. Co-immunoprecipitation showed that T. gondii abolishes binding of caspase 9 to Apaf-1 whereas the interaction of cytochrome c with Apaf-1 remains unchanged. Finally, T. gondii lysate mimics the effect of viable parasites and prevents holo-apoptosome functionality in a reconstituted in vitro system comprising recombinant Apaf-1 and caspase 9. Beside inhibition of cytochrome c release from host cell mitochondria, T. gondii thus also targets the holo-apoptosome assembly as a second mean to efficiently inhibit the caspase-dependent intrinsic cell death pathway.
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Affiliation(s)
- Kristin Graumann
- Institute for Medical Microbiology, Georg-August-University, Göttingen, Germany. ; Present address: In den Brühlwiesen 12, 61352 Bad Homburg, Germany
| | - Frieder Schaumburg
- Institute for Medical Microbiology, Georg-August-University, Göttingen, Germany. ; Present address: Institute for Medical Microbiology, University Hospital Münster, Domagkstraße 10, 48149 Münster, Germany
| | - Thomas F Reubold
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Diana Hippe
- Institute for Medical Microbiology, Georg-August-University, Göttingen, Germany
| | - Susanne Eschenburg
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Carsten G K Lüder
- Institute for Medical Microbiology, Georg-August-University, Göttingen, Germany
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206
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Sloves PJ, Mouveaux T, Ait-Yahia S, Vorng H, Everaere L, Sangare LO, Tsicopoulos A, Tomavo S. Apical Organelle Secretion by Toxoplasma Controls Innate and Adaptive Immunity and Mediates Long-Term Protection. J Infect Dis 2015; 212:1449-58. [PMID: 25910629 DOI: 10.1093/infdis/jiv250] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 04/10/2015] [Indexed: 01/06/2023] Open
Abstract
Apicomplexan parasites have unique apical rhoptry and microneme secretory organelles that are crucial for host infection, although their role in protection against Toxoplasma gondii infection is not thoroughly understood. Here, we report a novel function of the endolysosomal T. gondii sortilin-like receptor (TgSORTLR), which mediates trafficking to functional apical organelles and their subsequent secretion of virulence factors that are critical to the induction of sterile immunity against parasite reinfection. We further demonstrate that the T. gondii armadillo repeats-only protein (TgARO) mutant, which is deficient only in apical secretion of rhoptries, is also critical in mounting protective immunity. The lack of TgSORTLR and TgARO proteins completely inhibited T-helper 1-dependent adaptive immunity and compromised the function of natural killer T-cell-mediated innate immunity. Our findings reveal an essential role for apical secretion in promoting sterile protection against T. gondii and provide strong evidence for rhoptry-regulated discharge of antigens as a key effector for inducing protective immunity.
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Affiliation(s)
| | | | - Saliha Ait-Yahia
- Laboratory of Pulmonary Immunity, Center for Infection and Immunity of Lille, Centre National de la Recherche Scientfique (CNRS) Unité Mixte de Recherche (UMR) 8204, Institut National de la Santé et de la Recherche Médicale (NSERM), Unité ( U) 1019, Université de Lille, Institut Pasteur de Lille, France
| | - Han Vorng
- Laboratory of Pulmonary Immunity, Center for Infection and Immunity of Lille, Centre National de la Recherche Scientfique (CNRS) Unité Mixte de Recherche (UMR) 8204, Institut National de la Santé et de la Recherche Médicale (NSERM), Unité ( U) 1019, Université de Lille, Institut Pasteur de Lille, France
| | - Laetitia Everaere
- Laboratory of Pulmonary Immunity, Center for Infection and Immunity of Lille, Centre National de la Recherche Scientfique (CNRS) Unité Mixte de Recherche (UMR) 8204, Institut National de la Santé et de la Recherche Médicale (NSERM), Unité ( U) 1019, Université de Lille, Institut Pasteur de Lille, France
| | | | - Anne Tsicopoulos
- Laboratory of Pulmonary Immunity, Center for Infection and Immunity of Lille, Centre National de la Recherche Scientfique (CNRS) Unité Mixte de Recherche (UMR) 8204, Institut National de la Santé et de la Recherche Médicale (NSERM), Unité ( U) 1019, Université de Lille, Institut Pasteur de Lille, France
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207
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Toxoplasma gondii isolate with genotype Chinese 1 triggers trophoblast apoptosis through oxidative stress and mitochondrial dysfunction in mice. Exp Parasitol 2015; 154:51-61. [PMID: 25913086 DOI: 10.1016/j.exppara.2015.04.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 04/01/2015] [Accepted: 04/19/2015] [Indexed: 01/04/2023]
Abstract
Congenital toxoplasmosis may result in abortion, severe mental retardation and neurologic damage in the offspring. Placental damage is considered as the key event in this disease. Here we show that maternal infection with Toxoplasma gondii Wh3 isolate of genotype Chinese 1, which is predominantly prevalent in China, induced trophoblast apoptosis of pregnant mouse. PCR array analysis of 84 key genes in the biogenesis and functions of mouse mitochondrion revealed that ten genes were up-regulated at least 2-fold in the Wh3 infection group, compared with those in the control. The elevated levels of reactive oxygen species (ROS), malondialdehyde (MDA) and 8-hydroxydeoxyguanosine (8-OHdG), as well as the decreased glutathione (GSH), were observed in the infected mice. The mRNA levels of NADPH oxidase 1 and glutathione peroxidase 6 (GPx6) were significantly increased. The production of excessive ROS was NADPH oxidase-dependent, which contributed to mitochondrial structural damage and mitochondrial dysfunction in placentas, followed by the cleavage of caspase-9 and caspase-3, and finally resulted in apoptosis of trophoblasts. All the above-mentioned phenomena were inhibited by pretreatment with the antioxidant of N-acetylcysteine (NAC). Taken together, we concluded that Wh3 infection during pregnancy may contribute to trophoblast apoptosis by oxidative stress-induced mitochondrial dysfunction and activation of the downstream signaling pathway.
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208
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Wang JL, Li TT, Li ZY, Huang SY, Ning HR, Zhu XQ. Rhoptry protein 47 gene sequence: A potential novel genetic marker for population genetic studies of Toxoplasma gondii. Exp Parasitol 2015; 154:1-4. [PMID: 25862398 DOI: 10.1016/j.exppara.2015.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 03/18/2015] [Indexed: 11/17/2022]
Abstract
Toxoplasma gondii, an obligate intracellular parasite, is able to infect many animal species and humans, and can cause toxoplasmosis of the host. In this study, we examined sequence variation in rhoptry protein 47 (ROP47) gene among T. gondii isolates originating from different hosts and geographical regions. The entire genome region of the ROP47 gene was amplified and sequenced, and phylogenetic relationship was reconstructed using maximum parsimony (MP), maximum likelihood (ML) and neighbor-joining (NJ), based on the ROP47 gene sequences. The results of sequence alignments showed that all ROP47 gene sequences were 396 bp in length. There were 19 variable nucleotide positions in the coding region, resulted in 16 amino acid substitutions (12.21%) among all examined T. gondii strains and the existence of polymorphic restriction sites for endonucleases SacI and AflIII, allowing the differentiation of the three major clonal lineage types I, II and III by PCR-RFLP. Phylogenetic analysis of ROP47 gene sequences showed that three major clonal lineage types I, II and III were clustered differently, consistent with PCR-RFLP results. These results suggest that ROP47 gene sequence may represent a potential novel genetic marker for population genetic studies of T. gondii isolates.
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Affiliation(s)
- Jin-Lei Wang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, China
| | - Ting-Ting Li
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, China
| | - Zhong-Yuan Li
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, China; College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang Province 163319, China
| | - Si-Yang Huang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, China
| | - Hong-Rui Ning
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, China; College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui Province 230036, China
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, China; College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui Province 230036, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University College of Veterinary Medicine, Yangzhou, Jiangsu Province 225009, China.
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209
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Xiao J, Yolken RH. Strain hypothesis of Toxoplasma gondii infection on the outcome of human diseases. Acta Physiol (Oxf) 2015; 213:828-45. [PMID: 25600911 DOI: 10.1111/apha.12458] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 10/13/2014] [Accepted: 01/12/2015] [Indexed: 12/28/2022]
Abstract
The intracellular protozoan Toxoplasma gondii is an exceptionally successful food and waterborne parasite that infects approximately 1 billion people worldwide. Genotyping of T. gondii isolates from all continents revealed a complex population structure. Recent research supports the notion that T. gondii genotype may be associated with disease severity. Here, we (1) discuss molecular and serological approaches for designation of T. gondii strain type, (2) overview the literatures on the association of T. gondii strain type and the outcome of human disease and (3) explore possible mechanisms underlying these strain-specific pathology and severity of human toxoplasmosis. Although no final conclusions can be drawn, it is clear that virulent strains (e.g. strains containing type I or atypical alleles) are significantly more often associated with increased frequency and severity of human toxoplasmosis. The significance of highly virulent strains can cause severe diseases in immunocompetent patients and might implicated in brain disorders such as schizophrenia should led to reconsideration of toxoplasmosis. Further studies that combine parasite strain typing and human factor analysis (e.g. immune status and genetic background) are required for better understanding of human susceptibility or resistance to toxoplasmosis.
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Affiliation(s)
- J. Xiao
- Stanley Division of Developmental Neurovirology; Department of Pediatrics; Johns Hopkins School of Medicine; Baltimore MD USA
| | - R. H. Yolken
- Stanley Division of Developmental Neurovirology; Department of Pediatrics; Johns Hopkins School of Medicine; Baltimore MD USA
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210
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Dual RNA sequencing reveals the expression of unique transcriptomic signatures in lipopolysaccharide-induced BV-2 microglial cells. PLoS One 2015; 10:e0121117. [PMID: 25811458 PMCID: PMC4374676 DOI: 10.1371/journal.pone.0121117] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 01/28/2015] [Indexed: 11/26/2022] Open
Abstract
Microglial cells become rapidly activated through interactions with pathogens, and the persistent activation of these cells is associated with various neurodegenerative diseases. Previous studies have investigated the transcriptomic signatures in microglia or macrophages using microarray technologies. However, this method has numerous restrictions, such as spatial biases, uneven probe properties, low sensitivity, and dependency on the probes spotted. To overcome this limitation and identify novel transcribed genes in response to LPS, we used RNA Sequencing (RNA-Seq) to determine the novel transcriptomic signatures in BV-2 microglial cells. Sequencing assessment and quality evaluation showed that approximately 263 and 319 genes (≥ 1.5 log2-fold), such as cytokines and chemokines, were strongly induced after 2 and 4 h, respectively, and the induction of several genes with unknown immunological functions was also observed. Importantly, we observed that previously unidentified transcription factors (TFs) (irf1, irf7, and irf9), histone demethylases (kdm4a) and DNA methyltransferases (dnmt3l) were significantly and selectively expressed in BV-2 microglial cells. The gene expression levels, transcription start sites (TSS), isoforms, and differential promoter usage revealed a complex pattern of transcriptional and post-transcriptional gene regulation upon infection with LPS. In addition, gene ontology, molecular networks and pathway analyses identified the top significantly regulated functional classification, canonical pathways and network functions at each activation status. Moreover, we further analyzed differentially expressed genes to identify transcription factor (TF) motifs (−950 to +50 bp of the 5’ upstream promoters) and epigenetic mechanisms. Furthermore, we confirmed that the expressions of key inflammatory genes as well as pro-inflammatory mediators in the supernatants were significantly induced in LPS treated primary microglial cells. This transcriptomic analysis is the first to show a comparison of the family-wide differential expression of most known immune genes and also reveal transcription evidence of multiple gene families in BV-2 microglial cells. Collectively, these findings reveal unique transcriptomic signatures in BV-2 microglial cells required for homeostasis and effective immune responses.
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211
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Mercier C, Cesbron-Delauw MF. Toxoplasma secretory granules: one population or more? Trends Parasitol 2015; 31:604. [PMID: 29496113 DOI: 10.1016/j.pt.2015.02.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Corinne Mercier
- Laboratoire Adaptation et Pathogénie des Microorganismes (LAPM), CNRS UMR 5163 - Université Joseph Fourier, Grenoble, France.
| | - Marie-France Cesbron-Delauw
- Laboratoire Adaptation et Pathogénie des Microorganismes (LAPM), CNRS UMR 5163 - Université Joseph Fourier, Grenoble, France.
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212
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Walwyn O, Skariah S, Lynch B, Kim N, Ueda Y, Vohora N, Choe J, Mordue DG. Forward genetics screens using macrophages to identify Toxoplasma gondii genes important for resistance to IFN-γ-dependent cell autonomous immunity. J Vis Exp 2015:52556. [PMID: 25867017 PMCID: PMC4401235 DOI: 10.3791/52556] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Toxoplasma gondii, the causative agent of toxoplasmosis, is an obligate intracellular protozoan pathogen. The parasite invades and replicates within virtually any warm blooded vertebrate cell type. During parasite invasion of a host cell, the parasite creates a parasitophorous vacuole (PV) that originates from the host cell membrane independent of phagocytosis within which the parasite replicates. While IFN-dependent-innate and cell mediated immunity is important for eventual control of infection, innate immune cells, including neutrophils, monocytes and dendritic cells, can also serve as vehicles for systemic dissemination of the parasite early in infection. An approach is described that utilizes the host innate immune response, in this case macrophages, in a forward genetic screen to identify parasite mutants with a fitness defect in infected macrophages following activation but normal invasion and replication in naïve macrophages. Thus, the screen isolates parasite mutants that have a specific defect in their ability to resist the effects of macrophage activation. The paper describes two broad phenotypes of mutant parasites following activation of infected macrophages: parasite stasis versus parasite degradation, often in amorphous vacuoles. The parasite mutants are then analyzed to identify the responsible parasite genes specifically important for resistance to induced mediators of cell autonomous immunity. The paper presents a general approach for the forward genetics screen that, in theory, can be modified to target parasite genes important for resistance to specific antimicrobial mediators. It also describes an approach to evaluate the specific macrophage antimicrobial mediators to which the parasite mutant is susceptible. Activation of infected macrophages can also promote parasite differentiation from the tachyzoite to bradyzoite stage that maintains chronic infection. Therefore, methodology is presented to evaluate the importance of the identified parasite gene to establishment of chronic infection.
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Affiliation(s)
- Odaelys Walwyn
- Department of Microbiology and Immunology, New York Medical College
| | - Sini Skariah
- Department of Microbiology and Immunology, New York Medical College
| | - Brian Lynch
- Department of Microbiology and Immunology, New York Medical College
| | - Nathaniel Kim
- Department of Microbiology and Immunology, New York Medical College
| | - Yukari Ueda
- Department of Microbiology and Immunology, New York Medical College
| | - Neal Vohora
- Department of Microbiology and Immunology, New York Medical College
| | - Josh Choe
- Department of Microbiology and Immunology, New York Medical College
| | - Dana G Mordue
- Department of Microbiology and Immunology, New York Medical College
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213
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Kong L, Zhang Q, Chao J, Wen H, Zhang Y, Chen H, Pappoe F, Zhang A, Xu X, Cai Y, Li M, Luo Q, Zhang L, Shen J. Polarization of macrophages induced by Toxoplasma gondii and its impact on abnormal pregnancy in rats. Acta Trop 2015; 143:1-7. [PMID: 25496968 DOI: 10.1016/j.actatropica.2014.12.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 11/24/2014] [Accepted: 12/01/2014] [Indexed: 11/30/2022]
Abstract
Toxoplasma gondii infection is the leading cause of fetal intrauterine growth retardation among the five kinds of pathogens termed as TORCH, including Toxoplasma, Rubella virus, Cytomegalo virus, herpes virus and others during pregnancy. Pathogens infect the fetus through the placenta. T. gondii infection may result in congenital toxoplasmosis, miscarriage, stillbirth, and preemie, and increase pregnancy complications. Adaptive immune response induced by T. gondii infection stimulates T cells and macrophages to produce high levels of cytokines. Physiologically, the microenvironment of pregnancy was Th2-dominant. Here we set up a pregnant Sprague-Dawley rat model, and reported the polarization of macrophages induced by genotype Chinese 1 strain (Wh6) of Toxoplasma, and its adverse impact on pregnancy. The results showed that Wh6 infection pre- or in-gestation both led to abnormal pregnancy outcomes. Peritoneal macrophages in pre-gestation infection were polarized toward classically activated macrophages (M1), while in-gestation infection drove macrophages to polarize toward M2 activation. The Th2-dominant immune response in pregnant rat somewhat inhibits the excessive bias of the macrophages toward M1, and partially, toward M2. Infection of pre- and in-gestation may alter the physiological immune microenvironment in pregnant rats, giving rise to abnormal pregnancy outcomes.
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MESH Headings
- Animals
- Arginase/metabolism
- Blotting, Western
- Cell Culture Techniques
- Cytokines/metabolism
- DNA, Protozoan/genetics
- Female
- Macrophage Activation/physiology
- Macrophages, Peritoneal/physiology
- Male
- Nitric Oxide/metabolism
- Pregnancy
- Pregnancy Complications, Infectious/immunology
- Pregnancy Complications, Infectious/parasitology
- Pregnancy Complications, Infectious/pathology
- Pregnancy Outcome
- Rats
- Rats, Sprague-Dawley
- Real-Time Polymerase Chain Reaction
- Th1 Cells/parasitology
- Toxoplasma/pathogenicity
- Toxoplasmosis, Animal/immunology
- Toxoplasmosis, Animal/parasitology
- Toxoplasmosis, Animal/pathology
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Affiliation(s)
- Lanting Kong
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Department of Parasitology, Anhui Medical University, Hefei 230022, PR China
| | - Qian Zhang
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Department of Parasitology, Anhui Medical University, Hefei 230022, PR China
| | - Jing Chao
- Department of Immunology, Anhui Medical Iniversity, Hefei 230022, PR China
| | - Huiqin Wen
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Department of Parasitology, Anhui Medical University, Hefei 230022, PR China
| | - Yihua Zhang
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Department of Parasitology, Anhui Medical University, Hefei 230022, PR China
| | - He Chen
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Department of Parasitology, Anhui Medical University, Hefei 230022, PR China
| | - Faustina Pappoe
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Department of Parasitology, Anhui Medical University, Hefei 230022, PR China
| | - Aimei Zhang
- The Central Laboratory of Affiliated Provincial Hospital of Anhui Medical University, Hefei 230022, PR China
| | - Xiucai Xu
- The Central Laboratory of Affiliated Provincial Hospital of Anhui Medical University, Hefei 230022, PR China
| | - Yihong Cai
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Department of Parasitology, Anhui Medical University, Hefei 230022, PR China
| | - Min Li
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Department of Parasitology, Anhui Medical University, Hefei 230022, PR China
| | - Qingli Luo
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Department of Parasitology, Anhui Medical University, Hefei 230022, PR China
| | - Linjie Zhang
- Department of Immunology, Anhui Medical Iniversity, Hefei 230022, PR China.
| | - Jilong Shen
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Department of Parasitology, Anhui Medical University, Hefei 230022, PR China.
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214
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Leroux LP, Dasanayake D, Rommereim LM, Fox BA, Bzik DJ, Jardim A, Dzierszinski FS. Secreted Toxoplasma gondii molecules interfere with expression of MHC-II in interferon gamma-activated macrophages. Int J Parasitol 2015; 45:319-32. [PMID: 25720921 DOI: 10.1016/j.ijpara.2015.01.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 01/16/2015] [Accepted: 01/18/2015] [Indexed: 11/15/2022]
Abstract
The obligate intracellular protozoan parasite Toxoplasma gondii interferes with major histocompatibility complex class II antigen presentation to dampen host CD4(+) T cell responses. While it is known that T. gondii inhibits major histocompatibility complex class II gene transcription and expression in infected host cells, the mechanism of this host manipulation is unknown. Here, we show that soluble parasite proteins inhibit IFNγ-induced expression of major histocompatibility complex class II on the surface of the infected cell in a dose-dependent response that was abolished by protease treatment. Subcellular fractionation of T. gondii tachyzoites revealed that the major histocompatibility complex class II inhibitory activity co-partitioned with rhoptries and/or dense granules. However, parasite mutants deleted for single rhoptries or dense granules genes (ROP1, 4/7, 14, 16 and 18 or GRA 2-9 and 12 knock-out strains) retained the ability to inhibit expression of major histocompatibility complex class II. In addition, excreted/secreted antigens released by extracellular tachyzoites displayed immunomodulatory activity characterized by an inhibition of major histocompatibility complex class II expression, and reduced expression and release of TNFα by macrophages. Tandem MS analysis of parasite excreted/secreted antigens generated a list of T. gondii secreted proteins that may participate in major histocompatibility complex class II inhibition and the modulation of host immune functions.
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Affiliation(s)
- Louis-Philippe Leroux
- Institute of Parasitology, McGill University, Parasitology Building, 21,111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada; Centre for Host-Parasite Interaction, McGill University, Parasitology Building, 21,111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Dayal Dasanayake
- Institute of Parasitology, McGill University, Parasitology Building, 21,111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada; Centre for Host-Parasite Interaction, McGill University, Parasitology Building, 21,111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Leah M Rommereim
- Geisel School of Medicine at Dartmouth, Borwell Research Building, 1 Medical Center Drive, Lebanon, NH 03756, USA
| | - Barbara A Fox
- Geisel School of Medicine at Dartmouth, Borwell Research Building, 1 Medical Center Drive, Lebanon, NH 03756, USA
| | - David J Bzik
- Geisel School of Medicine at Dartmouth, Borwell Research Building, 1 Medical Center Drive, Lebanon, NH 03756, USA
| | - Armando Jardim
- Institute of Parasitology, McGill University, Parasitology Building, 21,111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada; Centre for Host-Parasite Interaction, McGill University, Parasitology Building, 21,111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.
| | - Florence S Dzierszinski
- Institute of Parasitology, McGill University, Parasitology Building, 21,111 Lakeshore Road, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada; Carleton University Research Office, Dunton Tower, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
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215
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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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216
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Cohen SB, Denkers EY. The gut mucosal immune response toToxoplasma gondii. Parasite Immunol 2015; 37:108-17. [DOI: 10.1111/pim.12164] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 11/09/2014] [Indexed: 12/23/2022]
Affiliation(s)
- S. B. Cohen
- Department of Microbiology and Immunology; College of Veterinary Medicine; Cornell University; Ithaca NY USA
| | - E. Y. Denkers
- Department of Microbiology and Immunology; College of Veterinary Medicine; Cornell University; Ithaca NY USA
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217
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Hehl AB, Basso WU, Lippuner C, Ramakrishnan C, Okoniewski M, Walker RA, Grigg ME, Smith NC, Deplazes P. Asexual expansion of Toxoplasma gondii merozoites is distinct from tachyzoites and entails expression of non-overlapping gene families to attach, invade, and replicate within feline enterocytes. BMC Genomics 2015; 16:66. [PMID: 25757795 PMCID: PMC4340605 DOI: 10.1186/s12864-015-1225-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 01/07/2015] [Indexed: 12/21/2022] Open
Abstract
Background The apicomplexan parasite Toxoplasma gondii is cosmopolitan in nature, largely as a result of its highly flexible life cycle. Felids are its only definitive hosts and a wide range of mammals and birds serve as intermediate hosts. The latent bradyzoite stage is orally infectious in all warm-blooded vertebrates and establishes chronic, transmissible infections. When bradyzoites are ingested by felids, they transform into merozoites in enterocytes and expand asexually as part of their coccidian life cycle. In all other intermediate hosts, however, bradyzoites differentiate exclusively to tachyzoites, and disseminate extraintestinally to many cell types. Both merozoites and tachyzoites undergo rapid asexual population expansion, yet possess different effector fates with respect to the cells and tissues they develop in and the subsequent stages they differentiate into. Results To determine whether merozoites utilize distinct suites of genes to attach, invade, and replicate within feline enterocytes, we performed comparative transcriptional profiling on purified tachyzoites and merozoites. We used high-throughput RNA-Seq to compare the merozoite and tachyzoite transcriptomes. 8323 genes were annotated with sequence reads across the two asexually replicating stages of the parasite life cycle. Metabolism was similar between the two replicating stages. However, significant stage-specific expression differences were measured, with 312 transcripts exclusive to merozoites versus 453 exclusive to tachyzoites. Genes coding for 177 predicted secreted proteins and 64 membrane- associated proteins were annotated as merozoite-specific. The vast majority of known dense-granule (GRA), microneme (MIC), and rhoptry (ROP) genes were not expressed in merozoites. In contrast, a large set of surface proteins (SRS) was expressed exclusively in merozoites. Conclusions The distinct expression profiles of merozoites and tachyzoites reveal significant additional complexity within the T. gondii life cycle, demonstrating that merozoites are distinct asexual dividing stages which are uniquely adapted to their niche and biological purpose. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1225-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adrian B Hehl
- Institute of Parasitology-University of Zurich, Winterthurerstrasse 266a, Zürich, 8057, Switzerland.
| | - Walter U Basso
- Institute of Parasitology-University of Zurich, Winterthurerstrasse 266a, Zürich, 8057, Switzerland.
| | - Christoph Lippuner
- Institute of Parasitology-University of Zurich, Winterthurerstrasse 266a, Zürich, 8057, Switzerland. .,Current address: Department of Anaesthesiology and Pain Medicine, Inselspital, University of Bern, Freiburgstrasse, Bern, 3010, Switzerland.
| | - Chandra Ramakrishnan
- Institute of Parasitology-University of Zurich, Winterthurerstrasse 266a, Zürich, 8057, Switzerland.
| | - Michal Okoniewski
- Functional Genomics Center Zurich, Winterthurerstrasse 190, Zürich, 8057, Switzerland.
| | - Robert A Walker
- Institute of Parasitology-University of Zurich, Winterthurerstrasse 266a, Zürich, 8057, Switzerland. .,Queensland Tropical Health Alliance Research Laboratory, Faculty of Medicine, Health and Molecular Sciences, James Cook University, Cairns Campus, McGregor Road, Smithfield, QLD, 4878, Australia.
| | - Michael E Grigg
- Molecular Parasitology Section, Laboratory of Parasitic Diseases, NIAID, NIH, Bethesda, Maryland, USA.
| | - Nicholas C Smith
- Queensland Tropical Health Alliance Research Laboratory, Faculty of Medicine, Health and Molecular Sciences, James Cook University, Cairns Campus, McGregor Road, Smithfield, QLD, 4878, Australia.
| | - Peter Deplazes
- Institute of Parasitology-University of Zurich, Winterthurerstrasse 266a, Zürich, 8057, Switzerland.
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218
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Systems-based analysis of the Sarcocystis neurona genome identifies pathways that contribute to a heteroxenous life cycle. mBio 2015; 6:mBio.02445-14. [PMID: 25670772 PMCID: PMC4337577 DOI: 10.1128/mbio.02445-14] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sarcocystis neurona is a member of the coccidia, a clade of single-celled parasites of medical and veterinary importance including Eimeria, Sarcocystis, Neospora, and Toxoplasma. Unlike Eimeria, a single-host enteric pathogen, Sarcocystis, Neospora, and Toxoplasma are two-host parasites that infect and produce infectious tissue cysts in a wide range of intermediate hosts. As a genus, Sarcocystis is one of the most successful protozoan parasites; all vertebrates, including birds, reptiles, fish, and mammals are hosts to at least one Sarcocystis species. Here we sequenced Sarcocystis neurona, the causal agent of fatal equine protozoal myeloencephalitis. The S. neurona genome is 127 Mbp, more than twice the size of other sequenced coccidian genomes. Comparative analyses identified conservation of the invasion machinery among the coccidia. However, many dense-granule and rhoptry kinase genes, responsible for altering host effector pathways in Toxoplasma and Neospora, are absent from S. neurona. Further, S. neurona has a divergent repertoire of SRS proteins, previously implicated in tissue cyst formation in Toxoplasma. Systems-based analyses identified a series of metabolic innovations, including the ability to exploit alternative sources of energy. Finally, we present an S. neurona model detailing conserved molecular innovations that promote the transition from a purely enteric lifestyle (Eimeria) to a heteroxenous parasite capable of infecting a wide range of intermediate hosts. Sarcocystis neurona is a member of the coccidia, a clade of single-celled apicomplexan parasites responsible for major economic and health care burdens worldwide. A cousin of Plasmodium, Cryptosporidium, Theileria, and Eimeria, Sarcocystis is one of the most successful parasite genera; it is capable of infecting all vertebrates (fish, reptiles, birds, and mammals—including humans). The past decade has witnessed an increasing number of human outbreaks of clinical significance associated with acute sarcocystosis. Among Sarcocystis species, S. neurona has a wide host range and causes fatal encephalitis in horses, marine mammals, and several other mammals. To provide insights into the transition from a purely enteric parasite (e.g., Eimeria) to one that forms tissue cysts (Toxoplasma), we present the first genome sequence of S. neurona. Comparisons with other coccidian genomes highlight the molecular innovations that drive its distinct life cycle strategies.
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219
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Zhou J, Gan X, Wang Y, Zhang X, Ding X, Chen L, Du J, Luo Q, Wang T, Shen J, Yu L. Toxoplasma gondii prevalent in China induce weaker apoptosis of neural stem cells C17.2 via endoplasmic reticulum stress (ERS) signaling pathways. Parasit Vectors 2015; 8:73. [PMID: 25649541 PMCID: PMC4322664 DOI: 10.1186/s13071-015-0670-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Accepted: 01/18/2015] [Indexed: 11/10/2022] Open
Abstract
Background Toxoplasma gondii, an obligate intracellular pathogen, has a strong affinity for the nervous system. TgCtwh3, a representative Chinese 1 Toxoplasma strain prevalent in China, has the polymorphic features of the effectors ROP16I/III with type I and GRA15II with type II Toxoplasma strains. The interaction of this atypical strain with host cells remains extremely elusive. Methods Using a transwell system, neural stem cells C17.2 were co-cultured with the tachyzoites of TgCtwh3 or standard type I RH strain. The apoptosis levels of C17.2 cells and the expression levels of related proteins in the endoplasmic reticulum stress (ERS)-mediated pathway were detected by flow cytometry and Western blotting. Results The apoptosis level of C17.2 cells co-cultured with TgCtwh3 had a significant increase compared to the negative control group; however, the apoptosis level in the TgCtwh3 group was significantly lower than that in the RH co-culture group. Western blotting analyses reveal that, after the C17.2 cells were co-cultured with TgCtwh3 and RH tachyzoites, the expression levels of caspase-12, CHOP and p-JNK in the cells increased significantly when compared to the control groups. After the pretreatment of Z-ATAD-FMK, an inhibitor of caspase-12, the apoptosis level of the C17.2 cells co-cultured with TgCtwh3 or RH tachyzoites had an apparent decline, and correspondingly, the expression levels of those related proteins were notably decreased. Conclusions Our findings suggest that TgCtwh3 may induce the apoptosis of the C17.2 cells by up-regulation of caspase-12, CHOP, and p-JNK, which are associated with ERS signaling pathways. This work contributes to better understanding the possible mechanism of brain pathology induced by T. gondii Chinese 1 isolates prevalent in China, and also reveals the potential value of ERS inhibitors to treat such related diseases in the future.
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Affiliation(s)
- Jie Zhou
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, 230032, PR China. .,Clinical Laboratory, People's Hospital of Huaibei, Huaibei, 235000, PR China.
| | - Xiaofeng Gan
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, 230032, PR China.
| | - Yongzhong Wang
- College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou, 310018, PR China. .,School of Life Sciences, Anhui University, Hefei, 230039, PR China.
| | - Xian Zhang
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, 230032, PR China.
| | - Xiaojuan Ding
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, 230032, PR China.
| | - Lingzhi Chen
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, 230032, PR China.
| | - Jian Du
- Department of Biochemistry, Anhui Medical University, Hefei, 230032, PR China.
| | - Qingli Luo
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, 230032, PR China.
| | - Teng Wang
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, 230032, PR China. .,HTS & Compound Management, HD Biosciences Corporation, Shanghai, 201201, PR China.
| | - Jilong Shen
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, 230032, PR China.
| | - Li Yu
- Department of Microbiology and Parasitology, Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Key Laboratory of Zoonoses, Anhui Medical University, Hefei, 230032, PR China.
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220
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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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221
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Mercier C, Cesbron-Delauw MF. Toxoplasma secretory granules: one population or more? Trends Parasitol 2015; 31:60-71. [PMID: 25599584 DOI: 10.1016/j.pt.2014.12.002] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/10/2014] [Accepted: 12/10/2014] [Indexed: 01/20/2023]
Abstract
In Toxoplasma gondii, dense granules are known as the storage secretory organelles of the so-called GRA proteins (for dense granule proteins), which are destined to the parasitophorous vacuole (PV) and the PV-derived cyst wall. Recently, newly annotated GRA proteins targeted to the host cell nucleus have enlarged this view. Here we provide an update on the latest developments on the Toxoplasma secreted proteins, which to date have been mainly studied at both the tachyzoite and bradyzoite stages, and we point out that recent discoveries could open the issue of a possible, yet uncharacterized, distinct secretory pathway in Toxoplasma.
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Affiliation(s)
- Corinne Mercier
- Laboratoire Adaptation et Pathogénie des Microorganismes (LAPM), CNRS UMR 5163 - Université Joseph Fourier, Grenoble, France.
| | - Marie-France Cesbron-Delauw
- Laboratoire Adaptation et Pathogénie des Microorganismes (LAPM), CNRS UMR 5163 - Université Joseph Fourier, Grenoble, France.
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222
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Via A, Uyar B, Brun C, Zanzoni A. How pathogens use linear motifs to perturb host cell networks. Trends Biochem Sci 2014; 40:36-48. [PMID: 25475989 DOI: 10.1016/j.tibs.2014.11.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 11/03/2014] [Accepted: 11/03/2014] [Indexed: 12/31/2022]
Abstract
Molecular mimicry is one of the powerful stratagems that pathogens employ to colonise their hosts and take advantage of host cell functions to guarantee their replication and dissemination. In particular, several viruses have evolved the ability to interact with host cell components through protein short linear motifs (SLiMs) that mimic host SLiMs, thus facilitating their internalisation and the manipulation of a wide range of cellular networks. Here we present convincing evidence from the literature that motif mimicry also represents an effective, widespread hijacking strategy in prokaryotic and eukaryotic parasites. Further insights into host motif mimicry would be of great help in the elucidation of the molecular mechanisms behind host cell invasion and the development of anti-infective therapeutic strategies.
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Affiliation(s)
- Allegra Via
- Department of Physics, Sapienza University, 00185 Rome, Italy
| | - Bora Uyar
- Structural and Computational Biology, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Christine Brun
- Inserm, UMR1090 TAGC, Marseille F-13288, France; Aix-Marseille Université, UMR1090 TAGC, Marseille F-13288, France; CNRS, Marseille F-13402, France
| | - Andreas Zanzoni
- Inserm, UMR1090 TAGC, Marseille F-13288, France; Aix-Marseille Université, UMR1090 TAGC, Marseille F-13288, France.
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223
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Han SJ, Melichar HJ, Coombes JL, Chan SW, Koshy AA, Boothroyd JC, Barton GM, Robey EA. Internalization and TLR-dependent type I interferon production by monocytes in response to Toxoplasma gondii. Immunol Cell Biol 2014; 92:872-81. [PMID: 25155465 PMCID: PMC4245188 DOI: 10.1038/icb.2014.70] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 06/25/2014] [Accepted: 06/27/2014] [Indexed: 12/20/2022]
Abstract
The classic anti-viral cytokine interferon (IFN)-β can be induced during parasitic infection, but relatively little is know about the cell types and signaling pathways involved. Here we show that inflammatory monocytes (IMs), but not neutrophils, produce IFN-β in response to T. gondii infection. This difference correlated with the mode of parasite entry into host cells, with phagocytic uptake predominating in IMs and active invasion predominating in neutrophils. We also show that expression of IFN-β requires phagocytic uptake of the parasite by IMs, and signaling through Toll-like receptors (TLRs) and MyD88. Finally, we show that IMs are major producers of IFN-β in mesenteric lymph nodes following in vivo oral infection of mice, and mice lacking the receptor for type I IFN-1 show higher parasite loads and reduced survival. Our data reveal a TLR and internalization-dependent pathway in IMs for IFN-β induction to a non-viral pathogen.
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Affiliation(s)
- Seong-Ji Han
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Heather J. Melichar
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Janine L. Coombes
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Shiao Wei Chan
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Anita A. Koshy
- Department of Medicine (Infectious Disease) and Department of Neurology, Stanford University School of Medicine, Stanford, California, USA
| | - John C. Boothroyd
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Gregory M. Barton
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Ellen A. Robey
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
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Hammondia hammondi harbors functional orthologs of the host-modulating effectors GRA15 and ROP16 but is distinguished from Toxoplasma gondii by a unique transcriptional profile. EUKARYOTIC CELL 2014; 13:1507-18. [PMID: 25280815 DOI: 10.1128/ec.00215-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Toxoplasma gondii and its nearest extant relative, Hammondia hammondi, are phenotypically distinct despite their remarkable similarity in gene content, synteny, and functionality. To begin to identify genetic differences that might drive distinct infection phenotypes of T. gondii and H. hammondi, in the present study we (i) determined whether two known host-interacting proteins, dense granule protein 15 (GRA15) and rhoptry protein 16 (ROP16), were functionally conserved in H. hammondi and (ii) performed the first comparative transcriptional analysis of H. hammondi and T. gondii sporulated oocysts. We found that GRA15 and ROP16 from H. hammondi (HhGRA15 and HhROP16) modulate the host NF-κB and STAT6 pathways, respectively, when expressed heterologously in T. gondii. We also found the transcriptomes of H. hammondi and T. gondii to be highly distinct. Consistent with the spontaneous conversion of H. hammondi tachyzoites into bradyzoites both in vitro and in vivo, H. hammondi high-abundance transcripts are enriched for genes that are of greater abundance in T. gondii bradyzoites. We also identified genes that are of high transcript abundance in H. hammondi but are poorly expressed in multiple T. gondii life stages, suggesting that these genes are uniquely expressed in H. hammondi. Taken together, these data confirm the functional conservation of known T. gondii virulence effectors in H. hammondi and point to transcriptional differences as a potential source of the phenotypic differences between these species.
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Ma JS, Sasai M, Ohshima J, Lee Y, Bando H, Takeda K, Yamamoto M. Selective and strain-specific NFAT4 activation by the Toxoplasma gondii polymorphic dense granule protein GRA6. ACTA ACUST UNITED AC 2014; 211:2013-32. [PMID: 25225460 PMCID: PMC4172224 DOI: 10.1084/jem.20131272] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ma et al. show that the Toxoplasma gondii polymorphic dense granule protein GRA6 triggers the activation of the host transcription factor NFAT4, thus affecting the host immune response and maximizing parasite virulence. Toxoplasma gondii infection results in co-option and subversion of host cellular signaling pathways. This process involves discharge of T. gondii effector molecules from parasite secretory organelles such as rhoptries and dense granules. We report that the T. gondii polymorphic dense granule protein GRA6 regulates activation of the host transcription factor nuclear factor of activated T cells 4 (NFAT4). GRA6 overexpression robustly and selectively activated NFAT4 via calcium modulating ligand (CAMLG). Infection with wild-type (WT) but not GRA6-deficient parasites induced NFAT4 activation. Moreover, GRA6-deficient parasites failed to exhibit full virulence in local infection, and the treatment of WT mice with an NFAT inhibitor mitigated virulence of WT parasites. Notably, NFAT4-deficient mice displayed prolonged survival, decreased recruitment of CD11b+ Ly6G+ cells to the site of infection, and impaired expression of chemokines such as Cxcl2 and Ccl2. In addition, infection with type I parasites culminated in significantly higher NFAT4 activation than type II parasites due to a polymorphism in the C terminus of GRA6. Collectively, our data suggest that GRA6-dependent NFAT4 activation is required for T. gondii manipulation of host immune responses to maximize the parasite virulence in a strain-dependent manner.
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Affiliation(s)
- Ji Su Ma
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Miwa Sasai
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Jun Ohshima
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Youngae Lee
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Hironori Bando
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
| | - Kiyoshi Takeda
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Saitama 332-0012, Japan
| | - Masahiro Yamamoto
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan Department of Immunoparasitology, Research Institute for Microbial Diseases, Laboratory of Immunoparasitology, Laboratory of Mucosal Immunology, WPI Immunology Frontier Research Center, Department of Microbiology and Immunology, Graduate School of Medicine, and Department of Restorative Dentistry and Endodontology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan
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Das A, Chai JC, Jung KH, Das ND, Kang SC, Lee YS, Seo H, Chai YG. JMJD2A attenuation affects cell cycle and tumourigenic inflammatory gene regulation in lipopolysaccharide stimulated neuroectodermal stem cells. Exp Cell Res 2014; 328:361-78. [PMID: 25193078 DOI: 10.1016/j.yexcr.2014.08.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 07/21/2014] [Accepted: 08/19/2014] [Indexed: 01/05/2023]
Abstract
JMJD2A is a lysine trimethyl-specific histone demethylase that is highly expressed in a variety of tumours. The role of JMJD2A in tumour progression remains unclear. The objectives of this study were to identify JMJD2A-regulated genes and understand the function of JMJD2A in p53-null neuroectodermal stem cells (p53(-/-) NE-4Cs). We determined the effect of LPS as a model of inflammation in p53(-/-) NE-4Cs and investigated whether the epigenetic modifier JMJD2A alter the expression of tumourigenic inflammatory genes. Global gene expression was measured in JMJD2A knockdown (kd) p53(-/-) NE-4Cs and in LPS-stimulated JMJD2A-kd p53(-/-) NE-4C cells. JMJD2A attenuation significantly down-regulated genes were Cdca2, Ccnd2, Ccnd1, Crebbp, IL6rα, and Stat3 related with cell cycle, proliferation, and inflammatory-disease responses. Importantly, some tumour-suppressor genes including Dapk3, Timp2 and TFPI were significantly up-regulated but were not affected by silencing of the JMJD2B. Furthermore, we confirmed the attenuation of JMJD2A also down-regulated Cdca2, Ccnd2, Crebbp, and Rest in primary NSCs isolated from the forebrains of E15 embryos of C57/BL6J mice with effective p53 inhibitor pifithrin-α (PFT-α). Transcription factor (TF) motif analysis revealed known binding patterns for CDC5, MYC, and CREB, as well as three novel motifs in JMJD2A-regulated genes. IPA established molecular networks. The molecular network signatures and functional gene-expression profiling data from this study warrants further investigation as an effective therapeutic target, and studies to elucidate the molecular mechanism of JMJD2A-kd-dependent effects in neuroectodermal stem cells should be performed.
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Affiliation(s)
- Amitabh Das
- Department of Bionanotechnology, Hanyang University, Seoul 133-791, Republic of Korea.
| | - Jin Choul Chai
- Department of Molecular & Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do, Republic of Korea.
| | - Kyoung Hwa Jung
- Department of Molecular & Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do, Republic of Korea.
| | - Nando Dulal Das
- Clinical Research Centre, Inha University School of Medicine, Incheon 400-711, Republic of Korea.
| | - Sung Chul Kang
- Department of Molecular & Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do, Republic of Korea.
| | - Young Seek Lee
- Department of Molecular & Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do, Republic of Korea.
| | - Hyemyung Seo
- Department of Molecular & Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do, Republic of Korea.
| | - Young Gyu Chai
- Department of Bionanotechnology, Hanyang University, Seoul 133-791, Republic of Korea; Department of Molecular & Life Science, Hanyang University, 1271 Sa 3-dong, Ansan 426-791, Gyeonggi-do, Republic of Korea.
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227
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Use of transgenic parasites and host reporters to dissect events that promote interleukin-12 production during toxoplasmosis. Infect Immun 2014; 82:4056-67. [PMID: 25024368 DOI: 10.1128/iai.01643-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The intracellular parasite Toxoplasma gondii has multiple strategies to alter host cell function, including the injection of rhoptry proteins into the cytosol of host cells as well as bystander populations, but the consequence of these events is unclear. Here, a reporter system using fluorescent parasite strains that inject Cre recombinase with their rhoptry proteins (Toxoplasma-Cre) was combined with Ai6 Cre reporter mice to identify cells that have been productively infected, that have been rhoptry injected but lack the parasite, or that have phagocytosed T. gondii. The ability to distinguish these host-parasite interactions was then utilized to dissect the events that lead to the production of interleukin-12 p40 (IL-12p40), which is required for resistance to T. gondii. In vivo, the use of invasion-competent or invasion-inhibited (phagocytosed) parasites with IL-12p40 (YET40) reporter mice revealed that dendritic cell (DC) and macrophage populations that phagocytose the parasite or are infected can express IL-12p40 but are not the major source, as larger numbers of uninfected cells secrete this cytokine. Similarly, the use of Toxoplasma-Cre parasite strains indicated that dendritic cells and inflammatory monocytes untouched by the parasite and not cells injected by the parasite are the primary source of IL-12p40. These results imply that a soluble host or parasite factor is responsible for the bulk of IL-12p40 production in vivo, rather than cellular interactions with T. gondii that result in infection, infection and clearance, injection of rhoptry proteins, or phagocytosis of the parasite.
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228
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Type II Toxoplasma gondii induction of CD40 on infected macrophages enhances interleukin-12 responses. Infect Immun 2014; 82:4047-55. [PMID: 25024369 DOI: 10.1128/iai.01615-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Toxoplasma gondii is an obligate intracellular parasite that can cause severe neurological disease in infected humans. CD40 is a receptor on macrophages that plays a critical role in controlling T. gondii infection. We examined the regulation of CD40 on the surface of T. gondii-infected bone marrow-derived macrophages (BMdMs). T. gondii induced CD40 expression both at the transcript level and on the cell surface, and interestingly, the effect was parasite strain specific: CD40 levels were dramatically increased in type II T. gondii-infected BMdMs compared to type I- or type III-infected cells. Type II induction of CD40 was specific to cells harboring intracellular parasites and detectable as early as 6 h postinfection (hpi) at the transcript level. CD40 protein expression peaked at 18 hpi. Using forward genetics with progeny from a type II × type III cross, we found that CD40 induction mapped to a region of chromosome X that included the gene encoding the dense granule protein 15 (GRA15). Using type I parasites stably expressing the type II allele of GRA15 (GRA15II), we found that type I GRA15II parasites induced the expression of CD40 on infected cells in an NF-κB-dependent manner. In addition, stable expression of hemagglutinin-tagged GRA15II in THP-1 cells resulted in CD40 upregulation in the absence of infection. Since CD40 signaling contributes to interleukin-12 (IL-12) production, we examined IL-12 from infected macrophages and found that CD40L engagement of CD40 amplified the IL-12 response in type II-infected cells. These data indicate that GRA15II induction of CD40 promotes parasite immunity through the production of IL-12.
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229
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de-la-Torre A, Pfaff AW, Grigg ME, Villard O, Candolfi E, Gomez-Marin JE. Ocular cytokinome is linked to clinical characteristics in ocular toxoplasmosis. Cytokine 2014; 68:23-31. [PMID: 24787053 PMCID: PMC4889015 DOI: 10.1016/j.cyto.2014.03.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Revised: 03/16/2014] [Accepted: 03/23/2014] [Indexed: 01/01/2023]
Abstract
PURPOSE To determine the cytokine levels in aqueous humor (AH) of Colombian patients with active ocular toxoplasmosis (OT), and to correlate them with their clinical characteristics. METHODS 27 Cytokines/chemokines were assayed in 15 AH samples (nine patients with diagnosis of OT biologically-confirmed and six controls that underwent cataract surgery). Correlations were assessed between cytokine/chemokine levels, type of inflammatory response (Th1, Th2, Th17, Treg), and clinical characteristics. RESULTS Th2 predominant response was related to more severe clinical features. The presence of VEGF and IL-5 was related to higher number of recurrences. Growth factors (VEGF, FGF, PDGF-β), were related to higher number of lesions. Patients infected by type-I/III strains had a particular intraocular cytokine-pattern. CONCLUSIONS Th2 response was related to more severe clinical characteristics in patients infected by Type I/III strains. IL-5 and VEGF were associated with recurrences. We correlate for the first time, specific cytokine-patterns with clinical characteristics and with the infecting Toxoplasma strain.
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Affiliation(s)
- Alejandra de-la-Torre
- Universidad del Rosario, Escuela de Medicina y Ciencias de la Salud, Departamento de Inmunología, Bogotá, Colombia
| | - Alexander W Pfaff
- Institut de Parasitologie et Pathologie Tropicale, Fédération de Médecine Translationelle de Strasbourg, Université de Strasbourg, France
| | - Michael E Grigg
- Laboratory of Parasitic Diseases, National Institutes of Health, National Institute of Allergy and Infectious Diseases (NIAID), Bethesda, MD, USA
| | - Odile Villard
- Institut de Parasitologie et Pathologie Tropicale, Fédération de Médecine Translationelle de Strasbourg, Université de Strasbourg, France
| | - Ermanno Candolfi
- Institut de Parasitologie et Pathologie Tropicale, Fédération de Médecine Translationelle de Strasbourg, Université de Strasbourg, France
| | - Jorge E Gomez-Marin
- GEPAMOL, Centro de Investigaciones Biomédicas, Facultad de Ciencias de la Salud, Universidad del Quindío, Avenida Bolivar 12N, Armenia, Colombia.
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230
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Cohen SB, Denkers EY. Border maneuvers: deployment of mucosal immune defenses against Toxoplasma gondii. Mucosal Immunol 2014; 7:744-52. [PMID: 24717355 DOI: 10.1038/mi.2014.25] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 03/13/2014] [Indexed: 02/04/2023]
Abstract
Toxoplasma gondii is a highly prevalent protozoan pathogen that is transmitted through oral ingestion of infectious cysts. As such, mucosal immune defenses in the intestine constitute the first and arguably most important line of resistance against the parasite. The response to infection is now understood to involve complex three-way interactions between Toxoplasma, the mucosal immune system, and the host intestinal microbiota. Productive outcome of these interactions ensures resolution of infection in the intestinal mucosa. Nonsuccessful outcome may result in emergence of proinflammatory damage that can spell death for the host. Here, we discuss new advances in our understanding of the mechanisms underpinning these disparate outcomes, with particular reference to initiators, effectors, and regulators of mucosal immunity stimulated by Toxoplasma in the intestine.
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Affiliation(s)
- S B Cohen
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - E Y Denkers
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
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231
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Witola WH, Bauman B, McHugh M, Matthews K. Silencing of GRA10 protein expression inhibits Toxoplasma gondii intracellular growth and development. Parasitol Int 2014; 63:651-8. [PMID: 24832208 DOI: 10.1016/j.parint.2014.05.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 03/29/2014] [Accepted: 05/02/2014] [Indexed: 02/01/2023]
Abstract
Toxoplasma gondii dense granule proteins (GRAs) are secreted abundantly in both the tachyzoite and bradyzoite stages of the parasite and are known to localize to various compartments of the parasitophorous vacuole (PV) that interfaces with the host cell milieu. Thus, GRAs may play significant roles in the biogenesis of the PV that is important for survival of intracellular T. gondii. GRA10 is a dense granule protein whose role in T. gondii has not yet been characterized. Therefore, in this study, we endeavored to determine the role of GRA10 in the growth and survival of intracellular T. gondii by using phosphorodiamidate morpholino oligomers (PPMOs) antisense knockdown approach to disrupt the translation of GRA10 mRNA in the parasites. We expressed and purified a truncated recombinant GRA10 protein to generate anti-GRA10 polyclonal antibodies that we used to characterize GRA10 in T. gondii. We found that GRA10 is a soluble, dense granule-associated protein that is secreted into the parasite cytosol and the parasitophorous vacuole milieu. Using in vitro cultures, we found that knockdown of GRA10 results in severe inhibition of T. gondii growth in human fibroblasts and in ovine monocytic cells. Together, our findings define GRA10 as a dense granule protein that plays a significant role in the growth and propagation of intracellular T. gondii in human fibroblasts and in ovine monocytic cells.
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Affiliation(s)
- William H Witola
- Room 312 Milbank Hall, College of Agriculture, Environment and Nutrition Sciences, Tuskegee University, Tuskegee, AL 36088, USA.
| | - Bretta Bauman
- Room 312 Milbank Hall, College of Agriculture, Environment and Nutrition Sciences, Tuskegee University, Tuskegee, AL 36088, USA
| | - Mark McHugh
- Room 312 Milbank Hall, College of Agriculture, Environment and Nutrition Sciences, Tuskegee University, Tuskegee, AL 36088, USA
| | - Kwame Matthews
- Room 312 Milbank Hall, College of Agriculture, Environment and Nutrition Sciences, Tuskegee University, Tuskegee, AL 36088, USA
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232
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Du J, An R, Chen L, Shen Y, Chen Y, Cheng L, Jiang Z, Zhang A, Yu L, Chu D, Shen Y, Luo Q, Chen H, Wan L, Li M, Xu X, Shen J. WITHDRAWN: Toxoplasma gondii virulence factor ROP18 inhibits the host NF-κB pathway by promoting p65 degradation. J Biol Chem 2014; 289:12578-92. [PMID: 24648522 PMCID: PMC4007449 DOI: 10.1074/jbc.m113.544718] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 03/10/2014] [Indexed: 01/09/2023] Open
Abstract
The obligate intracellular parasite Toxoplasma gondii secretes effector molecules into the host cell to modulate host immunity. Previous studies have shown that T. gondii could interfere with host NF-κB signaling to promote their survival, but the effectors of type I strains remain unclear. The polymorphic rhoptry protein ROP18 is a key serine/threonine kinase that phosphorylates host proteins to modulate acute virulence. Our data demonstrated that the N-terminal portion of ROP18 is associated with the dimerization domain of p65. ROP18 phosphorylates p65 at Ser-468 and targets this protein to the ubiquitin-dependent degradation pathway. The kinase activity of ROP18 is required for p65 degradation and suppresses NF-κB activation. Consistently, compared with wild-type ROP18 strain, ROP18 kinase-deficient type I parasites displayed a severe inability to inhibit NF-κB, culminating in the enhanced production of IL-6, IL-12, and TNF-α in infected macrophages. In addition, studies have shown that transgenic parasites carrying kinase-deficient ROP18 induce M1-biased activation. These results demonstrate for the first time that the virulence factor ROP18 in T. gondii type I strains is responsible for inhibiting the host NF-κB pathway and for suppressing proinflammatory cytokine expression, thus providing a survival advantage to the infectious agent.
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Affiliation(s)
- Jian Du
- From the Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China
| | - Ran An
- From the Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China
| | - Lijian Chen
- Department of Anesthesiology, the First Affiliated Hospital of Anhui Medical University, Hefei 230032, China
| | - Yuxian Shen
- Institute of Biopharmaceuticals, Anhui Medical University, Hefei 230032, China
| | - Ying Chen
- Institute of Biopharmaceuticals, Anhui Medical University, Hefei 230032, China
| | - Li Cheng
- From the Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China
| | - Zhongru Jiang
- From the Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China
| | - Aimei Zhang
- Central Laboratory of Affiliated Provincial Hospital of Anhui Medical University, Hefei 230001, China, and
| | - Li Yu
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Medical University, Hefei 230032, China
| | - Deyong Chu
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Medical University, Hefei 230032, China
| | - Yujun Shen
- Institute of Biopharmaceuticals, Anhui Medical University, Hefei 230032, China
| | - Qingli Luo
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Medical University, Hefei 230032, China
| | - He Chen
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Medical University, Hefei 230032, China
| | - Lijuan Wan
- From the Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Anhui Medical University, Hefei 230032, China
| | - Min Li
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Medical University, Hefei 230032, China
| | - Xiucai Xu
- Central Laboratory of Affiliated Provincial Hospital of Anhui Medical University, Hefei 230001, China, and
| | - Jilong Shen
- Anhui Provincial Laboratory of Microbiology and Parasitology, Anhui Medical University, Hefei 230032, China
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233
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Toxoplasma effector MAF1 mediates recruitment of host mitochondria and impacts the host response. PLoS Biol 2014; 12:e1001845. [PMID: 24781109 PMCID: PMC4004538 DOI: 10.1371/journal.pbio.1001845] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 03/21/2014] [Indexed: 11/23/2022] Open
Abstract
The intracellular human protozoan parasite Toxoplasma gondii uses a novel secreted protein to recruit host mitochondria and alter the host's response to infection. Recent information has revealed the functional diversity and importance of mitochondria in many cellular processes including orchestrating the innate immune response. Intriguingly, several infectious agents, such as Toxoplasma, Legionella, and Chlamydia, have been reported to grow within vacuoles surrounded by host mitochondria. Although many hypotheses have been proposed for the existence of host mitochondrial association (HMA), the causes and biological consequences of HMA have remained unanswered. Here we show that HMA is present in type I and III strains of Toxoplasma but missing in type II strains, both in vitro and in vivo. Analysis of F1 progeny from a type II×III cross revealed that HMA is a Mendelian trait that we could map. We use bioinformatics to select potential candidates and experimentally identify the polymorphic parasite protein involved, mitochondrial association factor 1 (MAF1). We show that introducing the type I (HMA+) MAF1 allele into type II (HMA−) parasites results in conversion to HMA+ and deletion of MAF1 in type I parasites results in a loss of HMA. We observe that the loss and gain of HMA are associated with alterations in the transcription of host cell immune genes and the in vivo cytokine response during murine infection. Lastly, we use exogenous expression of MAF1 to show that it binds host mitochondria and thus MAF1 is the parasite protein directly responsible for HMA. Our findings suggest that association with host mitochondria may represent a novel means by which Toxoplasma tachyzoites manipulate the host. The existence of naturally occurring HMA+ and HMA− strains of Toxoplasma, Legionella, and Chlamydia indicates the existence of evolutionary niches where HMA is either advantageous or disadvantageous, likely reflecting tradeoffs in metabolism, immune regulation, and other functions of mitochondria. Recent discoveries have revealed the remarkable functional diversity of mitochondria in roles other than energy production, including an integral role for mitochondria and their dynamics in the regulation of the innate immune response. Interestingly, host mitochondria are recruited to the membranes that surround certain intracellular bacteria and parasites during infection. To date, how and why this phenomenon occurs has been a mystery, although it has been proposed to provide a metabolic benefit to the microbes. Here we identify mitochondrial association factor 1 (MAF1) as the parasite protein that mediates the association between the protozoan pathogen Toxoplasma and host mitochondria during infection. We show that MAF1 is needed to recruit host mitochondria to the Toxoplasma-containing vacuole and that this process is associated with changes in the immune response in infected cells and animals. These findings show that recruitment and association with host mitochondria is an important means by which intracellular pathogens interface with their host. We also find that the cost–benefit outcome of altering mitochondrial function might differ between strains depending on the precise niche in which they evolved; for infectious agents, these differences likely reflect different host organisms.
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Avirulent strains of Toxoplasma gondii infect macrophages by active invasion from the phagosome. Proc Natl Acad Sci U S A 2014; 111:6437-42. [PMID: 24733931 DOI: 10.1073/pnas.1316841111] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Unlike most intracellular pathogens that gain access into host cells through endocytic pathways, Toxoplasma gondii initiates infection at the cell surface by active penetration through a moving junction and subsequent formation of a parasitophorous vacuole. Here, we describe a noncanonical pathway for T. gondii infection of macrophages, in which parasites are initially internalized through phagocytosis, and then actively invade from within a phagosomal compartment to form a parasitophorous vacuole. This phagosome to vacuole invasion (PTVI) pathway may represent an intermediary link between the endocytic and the penetrative routes for host cell entry by intracellular pathogens. The PTVI pathway is preferentially used by avirulent strains of T. gondii and confers an infectious advantage over virulent strains for macrophage tropism.
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GRA25 is a novel virulence factor of Toxoplasma gondii and influences the host immune response. Infect Immun 2014; 82:2595-605. [PMID: 24711568 DOI: 10.1128/iai.01339-13] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The obligate intracellular parasite Toxoplasma gondii is able to infect a broad range of hosts and cell types due, in part, to the diverse arsenal of effectors it secretes into the host cell. Here, using genetic crosses between type II and type III Toxoplasma strains and quantitative trait locus (QTL) mapping of the changes they induce in macrophage gene expression, we identify a novel dense granule protein, GRA25. Encoded on chromosome IX, GRA25 is a phosphoprotein that is secreted outside the parasites and is found within the parasitophorous vacuole. In vitro experiments with a type II Δgra25 strain showed that macrophages infected with this strain secrete lower levels of CCL2 and CXCL1 than those infected with the wild-type or complemented control parasites. In vivo experiments showed that mice infected with a type II Δgra25 strain are able to survive an otherwise lethal dose of Toxoplasma tachyzoites and that complementation of the mutant with an ectopic copy of GRA25 largely rescues this phenotype. Interestingly, the type II and type III versions of GRA25 differ in endogenous expression levels; however, both are able to promote parasite expansion in vivo when expressed in a type II Δgra25 strain. These data establish GRA25 as a novel virulence factor and immune modulator.
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Host cell subversion by Toxoplasma GRA16, an exported dense granule protein that targets the host cell nucleus and alters gene expression. Cell Host Microbe 2014; 13:489-500. [PMID: 23601110 DOI: 10.1016/j.chom.2013.03.002] [Citation(s) in RCA: 168] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 01/17/2013] [Accepted: 02/14/2013] [Indexed: 01/17/2023]
Abstract
After invading host cells, Toxoplasma gondii multiplies within a parasitophorous vacuole (PV) that is maintained by parasite proteins secreted from organelles called dense granules. Most dense granule proteins remain within the PV, and few are known to access the host cell cytosol. We identify GRA16 as a dense granule protein that is exported through the PV membrane and reaches the host cell nucleus, where it positively modulates genes involved in cell-cycle progression and the p53 tumor suppressor pathway. GRA16 binds two host enzymes, the deubiquitinase HAUSP and PP2A phosphatase, which exert several functions, including regulation of p53 and the cell cycle. GRA16 alters p53 levels in a HAUSP-dependent manner and induces nuclear translocation of the PP2A holoenzyme. Additionally, certain GRA16-deficient strains exhibit attenuated virulence, indicating the importance of these host alterations in pathogenesis. Therefore, GRA16 represents a potentially emerging subfamily of exported dense granule proteins that modulate host function.
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Cannella D, Brenier-Pinchart MP, Braun L, van Rooyen J, Bougdour A, Bastien O, Behnke M, Curt RL, Curt A, Saeij J, Sibley L, Pelloux H, Hakimi MA. miR-146a and miR-155 Delineate a MicroRNA Fingerprint Associated with Toxoplasma Persistence in the Host Brain. Cell Rep 2014; 6:928-37. [DOI: 10.1016/j.celrep.2014.02.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Revised: 01/23/2014] [Accepted: 02/03/2014] [Indexed: 10/25/2022] Open
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Silva LA, Andrade RO, Carneiro ACAV, Vitor RWA. Overlapping Toxoplasma gondii genotypes circulating in domestic animals and humans in Southeastern Brazil. PLoS One 2014; 9:e90237. [PMID: 24587295 PMCID: PMC3937362 DOI: 10.1371/journal.pone.0090237] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 01/27/2014] [Indexed: 12/21/2022] Open
Abstract
Although several Toxoplasma gondii genotyping studies have been performed in Brazil, studies of isolates from animals in the state of Minas Gerais are rare. The objective of this study was to conduct a genotypic characterization of T. gondii isolates obtained from dogs, free-range chickens, and humans in Minas Gerais and to verify whether the T. gondii genotypes circulating in domestic animals correspond to the genotypes detected in humans. Genetic variability was assessed by restricted fragment length polymorphism at 11 loci (SAG1, 5′+3′SAG2, SAG2 alt, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). Twelve different genotypes were identified among the 24 isolates studied, including 8 previously identified genotypes and 4 new genotypes. The genetic relationship of the 24 T. gondii isolates, together with the genotypes previously described from 24 human newborns with congenital toxoplasmosis, revealed a high degree of similarity among the genotypes circulating in humans and animals in Minas Gerais. The most common genotypes among these species were BrII, BrIII, ToxoDB #108, and ToxoDB #206. Restricted fragment length polymorphism at the CS3 locus of these 48 isolates showed that the majority of isolates presented alleles I (50%) or II (27%). Isolates harboring allele III at the CS3 locus presented low virulence for mice, whereas those harboring alleles I or II presented higher virulence. These results confirm the utility of marker CS3 for predicting the virulence of Brazilian isolates of T. gondii in mice. No association was found between the allele type and clinical manifestations of human congenital toxoplasmosis. This is the first report of T. gondii genotyping that verifies the overlapping genotypes of T. gondii from humans and animals in the same geographic region of Brazil. Our results suggest that there is a common source of infection to the species studied, most likely oocysts contaminating the environment.
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Affiliation(s)
- Letícia A. Silva
- Department of Parasitology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Renata O. Andrade
- Department of Parasitology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Ana Carolina A. V. Carneiro
- Department of Parasitology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Ricardo W. A. Vitor
- Department of Parasitology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- * E-mail:
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Abstract
Induction of immunity that limits Toxoplasma gondii infection in mice is critically dependent on the activation of the innate immune response. In this study, we investigated the role of cytoplasmic nucleotide-binding domain and leucine-rich repeat containing a pyrin domain (NLRP) inflammasome sensors during acute toxoplasmosis in mice. We show that in vitro Toxoplasma infection of murine bone marrow-derived macrophages activates the NLRP3 inflammasome, resulting in the rapid production and cleavage of interleukin-1β (IL-1β), with no measurable cleavage of IL-18 and no pyroptosis. Paradoxically, Toxoplasma-infected mice produced large quantities of IL-18 but had no measurable IL-1β in their serum. Infection of mice deficient in NLRP3, caspase-1/11, IL-1R, or the inflammasome adaptor protein ASC led to decreased levels of circulating IL-18, increased parasite replication, and death. Interestingly, mice deficient in NLRP1 also displayed increased parasite loads and acute mortality. Using mice deficient in IL-18 and IL-18R, we show that this cytokine plays an important role in limiting parasite replication to promote murine survival. Our findings reveal T. gondii as a novel activator of the NLRP1 and NLRP3 inflammasomes in vivo and establish a role for these sensors in host resistance to toxoplasmosis. Inflammasomes are multiprotein complexes that are a major component of the innate immune system. They contain “sensor” proteins that are responsible for detecting various microbial and environmental danger signals and function by activating caspase-1, an enzyme that mediates cleavage and release of the proinflammatory cytokines interleukin-1β (IL-1β) and IL-18. Toxoplasma gondii is a highly successful protozoan parasite capable of infecting a wide range of host species that have variable levels of resistance. We report here that T. gondii is a novel activator of the NLRP1 and NLRP3 inflammasomes in vivo and establish a role for these sensors in host resistance to toxoplasmosis. Using mice deficient in IL-18 and IL-18R, we show that the IL-18 cytokine plays a pivotal role by limiting parasite replication to promote murine survival.
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240
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Infection by Toxoplasma gondii specifically induces host c-Myc and the genes this pivotal transcription factor regulates. EUKARYOTIC CELL 2014; 13:483-93. [PMID: 24532536 DOI: 10.1128/ec.00316-13] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Toxoplasma gondii infection has previously been described to cause dramatic changes in the host transcriptome by manipulating key regulators, including STATs, NF-κB, and microRNAs. Here, we report that Toxoplasma tachyzoites also mediate rapid and sustained induction of another pivotal regulator of host cell transcription, c-Myc. This induction is seen in cells infected with all three canonical types of Toxoplasma but not the closely related apicomplexan parasite Neospora caninum. Coinfection of cells with both Toxoplasma and Neospora still results in an increase in the level of host c-Myc, showing that c-Myc is actively upregulated by Toxoplasma infection (rather than repressed by Neospora). We further demonstrate that this upregulation may be mediated through c-Jun N-terminal protein kinase (JNK) and is unlikely to be a nonspecific host response, as heat-killed Toxoplasma parasites do not induce this increase and neither do nonviable parasites inside the host cell. Finally, we show that the induced c-Myc is active and that transcripts dependent on its function are upregulated, as predicted. Hence, c-Myc represents an additional way in which Toxoplasma tachyzoites have evolved to specifically alter host cell functions during intracellular growth.
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241
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Differential locus expansion distinguishes Toxoplasmatinae species and closely related strains of Toxoplasma gondii. mBio 2014; 5:e01003-13. [PMID: 24496792 PMCID: PMC3950507 DOI: 10.1128/mbio.01003-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Toxoplasma gondii is a human obligate intracellular parasite that has infected over 20% of the world population and has a vast intermediate host range compared to those of its nearest relatives Neospora caninum and Hammondia hammondi. While these 3 species have highly syntenic genomes (80 to 99%), in this study we examined and compared species-specific structural variations, specifically at loci that have undergone local (i.e., tandem) duplication and expansion. To do so, we used genomic sequence coverage analysis to identify and curate T. gondii and N. caninum loci that have undergone duplication and expansion (expanded loci [ELs]). The 53 T. gondii ELs are significantly enriched for genes with predicted signal sequences and single-exon genes and genes that are developmentally regulated at the transcriptional level. We validated 24 T. gondii ELs using comparative genomic hybridization; these data suggested significant copy number variation at these loci. High-molecular-weight Southern blotting for 3 T. gondii ELs revealed that copy number varies across T. gondii lineages and also between members of the same clonal lineage. Using similar methods, we identified 64 N. caninum ELs which were significantly enriched genes belonging to the SAG-related surface (SRS) antigen family. Moreover, there is significantly less overlap (30%) between the expanded gene sets in T. gondii and N. caninum than would be predicted by overall genomic synteny (81%). Consistent with this finding, only 59% of queried T. gondii ELs are similarly duplicated/expanded in H. hammondi despite over 99% genomic synteny between these species. Gene duplication, expansion, and diversification are a basis for phenotypic differences both within and between species. This study represents the first characterization of both the extent and degree of overlap in gene duplication and locus expansion across multiple apicomplexan parasite species. The most important finding of this study is that the locus duplications/expansions are quantitatively and qualitatively distinct, despite the high degree of genetic relatedness between the species. Given that these differential expansions are prominent species-specific genetic differences, they may also contribute to some of the more striking phenotypic differences between these species. More broadly, this work is important in providing further support for the idea that postspeciation selection events may have a dramatic impact on locus structure and copy number that overshadows selection on single-copy genes.
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Bougdour A, Tardieux I, Hakimi MA. Toxoplasmaexports dense granule proteins beyond the vacuole to the host cell nucleus and rewires the host genome expression. Cell Microbiol 2014; 16:334-43. [DOI: 10.1111/cmi.12255] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 12/17/2013] [Accepted: 12/18/2013] [Indexed: 12/21/2022]
Affiliation(s)
- Alexandre Bougdour
- CNRS; UMR5163; LAPM; Grenoble 38041 France
- Université Joseph Fourier; Grenoble 38000 France
| | - Isabelle Tardieux
- Institut Cochin; INSERM U1016; CNRS UMR 8104; Université Paris Descartes; Paris 75014 France
| | - Mohamed-Ali Hakimi
- CNRS; UMR5163; LAPM; Grenoble 38041 France
- Université Joseph Fourier; Grenoble 38000 France
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Melo MB, Nguyen QP, Cordeiro C, Hassan MA, Yang N, McKell R, Rosowski EE, Julien L, Butty V, Dardé ML, Ajzenberg D, Fitzgerald K, Young LH, Saeij JPJ. Transcriptional analysis of murine macrophages infected with different Toxoplasma strains identifies novel regulation of host signaling pathways. PLoS Pathog 2013; 9:e1003779. [PMID: 24367253 PMCID: PMC3868521 DOI: 10.1371/journal.ppat.1003779] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 09/18/2013] [Indexed: 11/19/2022] Open
Abstract
Most isolates of Toxoplasma from Europe and North America fall into one of three genetically distinct clonal lineages, the type I, II and III lineages. However, in South America these strains are rarely isolated and instead a great variety of other strains are found. T. gondii strains differ widely in a number of phenotypes in mice, such as virulence, persistence, oral infectivity, migratory capacity, induction of cytokine expression and modulation of host gene expression. The outcome of toxoplasmosis in patients is also variable and we hypothesize that, besides host and environmental factors, the genotype of the parasite strain plays a major role. The molecular basis for these differences in pathogenesis, especially in strains other than the clonal lineages, remains largely unexplored. Macrophages play an essential role in the early immune response against T. gondii and are also the cell type preferentially infected in vivo. To determine if non-canonical Toxoplasma strains have unique interactions with the host cell, we infected murine macrophages with 29 different Toxoplasma strains, representing global diversity, and used RNA-sequencing to determine host and parasite transcriptomes. We identified large differences between strains in the expression level of known parasite effectors and large chromosomal structural variation in some strains. We also identified novel strain-specifically regulated host pathways, including the regulation of the type I interferon response by some atypical strains. IFNβ production by infected cells was associated with parasite killing, independent of interferon gamma activation, and dependent on endosomal Toll-like receptors in macrophages and the cytoplasmic receptor retinoic acid-inducible gene 1 (RIG-I) in fibroblasts.
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Affiliation(s)
- Mariane B. Melo
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Quynh P. Nguyen
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Cynthia Cordeiro
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
- Internal Medicine Department, School of Medicine, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Retina Service, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Musa A. Hassan
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Ninghan Yang
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Renée McKell
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Emily E. Rosowski
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Lindsay Julien
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Vincent Butty
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Marie-Laure Dardé
- Centre National de Référence Toxoplasmose/Toxoplasma Biological Resource Center, Centre Hospitalier-Universitaire Dupuytren, Limoges, France
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1094, Neuroépidémiologie Tropicale, Laboratoire de Parasitologie-Mycologie, Faculté de Médecine, Université de Limoges, Limoges, France
| | - Daniel Ajzenberg
- Centre National de Référence Toxoplasmose/Toxoplasma Biological Resource Center, Centre Hospitalier-Universitaire Dupuytren, Limoges, France
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche 1094, Neuroépidémiologie Tropicale, Laboratoire de Parasitologie-Mycologie, Faculté de Médecine, Université de Limoges, Limoges, France
| | - Katherine Fitzgerald
- University of Massachusetts Medical School, Division of Infectious Diseases and Immunology, Worcester, Massachusetts, United States of America
| | - Lucy H. Young
- Retina Service, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jeroen P. J. Saeij
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
- * E-mail:
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Wujcicka W, Wilczyński J, Nowakowska D. Do the placental barrier, parasite genotype and Toll-like receptor polymorphisms contribute to the course of primary infection with various Toxoplasma gondii genotypes in pregnant women? Eur J Clin Microbiol Infect Dis 2013; 33:703-9. [PMID: 24292064 PMCID: PMC3996274 DOI: 10.1007/s10096-013-2017-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 11/06/2013] [Indexed: 11/24/2022]
Abstract
Toxoplasma gondii has a highly clonal genetic structure classified into three major genetic types, I, II, and III, plus additional recombinant and atypical strains. In humans, type I and atypical strains usually associate with severe toxoplasmosis. Type II strains, predominantly identified in European countries and the United States, correlate with a differential course of toxoplasmosis. During pregnancy, the important protective role of the placenta against maternal–fetal T. gondii transmission has been reported. T. gondii preferentially colonizes extravillous trophoblasts as compared to syncytiotrophoblasts. The latter compartment was suggested to act as the real barrier to the fetal dissemination of T. gondii. Alterations in immune response to particular T. gondii strains were observed. Higher transcription levels of IP-10, IL-1β, IL-6, IL-10, IL-12 cytokines, and NF-κB translocation to the nucleus were more often documented for type II strains than type I strains. Since the induction of IL-12 during type II infection was Myd88-dependent, the involvement of Toll-like receptors (TLRs) in the immunity against these strains was suggested. Differential expression of TLRs depends on placental cell types and gestational age. The expression of TLR2 and TLR4 in the first trimester of pregnancy was reported only for villous cytotrophoblasts and extravillous trophoblasts, but not for syncytiotrophoblasts. The involvement of single-nucleotide polymorphisms (SNPs) in the TLR genes in infectious pathogenicity, including toxoplasmic retinochoroiditis, points at a possible involvement of TLR alterations in immunity against T. gondii. We conclude that studies on TLR contributions in the maternal–fetal transmission of particular parasite strains and congenital toxoplasmosis are warranted.
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Affiliation(s)
- W Wujcicka
- Department of Fetal-Maternal Medicine and Gynecology, Polish Mother's Memorial Hospital Research Institute in Lodz, 281/289 Rzgowska Street, Lodz, 93-338, Poland
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Lim D, Gold DA, Julien L, Rosowski EE, Niedelman W, Yaffe MB, Saeij JPJ. Structure of the Toxoplasma gondii ROP18 kinase domain reveals a second ligand binding pocket required for acute virulence. J Biol Chem 2013; 288:34968-80. [PMID: 24129568 PMCID: PMC3843107 DOI: 10.1074/jbc.m113.523266] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 10/13/2013] [Indexed: 12/27/2022] Open
Abstract
At least a third of the human population is infected with the intracellular parasite Toxoplasma gondii, which contributes significantly to the disease burden in immunocompromised and neutropenic hosts and causes serious congenital complications when vertically transmitted to the fetus. Genetic analyses have identified the Toxoplasma ROP18 Ser/Thr protein kinase as a major factor mediating acute virulence in mice. ROP18 is secreted into the host cell during the invasion process, and its catalytic activity is required for the acute virulence phenotype. However, its precise molecular function and regulation are not fully understood. We have determined the crystal structure of the ROP18 kinase domain, which is inconsistent with a previously proposed autoinhibitory mechanism of regulation. Furthermore, a sucrose molecule bound to our structure identifies an additional ligand-binding pocket outside of the active site cleft. Mutational analysis confirms an important role for this pocket in virulence.
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Affiliation(s)
- Daniel Lim
- From the Department of Biology and
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | | | | | | | | | - Michael B. Yaffe
- From the Department of Biology and
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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246
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Toxoplasma gondii Inhibits gamma interferon (IFN-γ)- and IFN-β-induced host cell STAT1 transcriptional activity by increasing the association of STAT1 with DNA. Infect Immun 2013; 82:706-19. [PMID: 24478085 DOI: 10.1128/iai.01291-13] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The gamma interferon (IFN-γ) response, mediated by the STAT1 transcription factor, is crucial for host defense against the intracellular pathogen Toxoplasma gondii, but prior infection with Toxoplasma can inhibit this response. Recently, it was reported that the Toxoplasma type II NTE strain prevents the recruitment of chromatin remodeling complexes containing Brahma-related gene 1 (BRG-1) to promoters of IFN-γ-induced secondary response genes such as Ciita and major histocompatibility complex class II genes in murine macrophages, thereby inhibiting their expression. We report here that a type I strain of Toxoplasma inhibits the expression of primary IFN-γ response genes such as IRF1 through a distinct mechanism not dependent on the activity of histone deacetylases. Instead, infection with a type I, II, or III strain of Toxoplasma inhibits the dissociation of STAT1 from DNA, preventing its recycling and further rounds of STAT1-mediated transcriptional activation. This leads to increased IFN-γ-induced binding of STAT1 at the IRF1 promoter in host cells and increased global IFN-γ-induced association of STAT1 with chromatin. Toxoplasma type I infection also inhibits IFN-β-induced interferon-stimulated gene factor 3-mediated gene expression, and this inhibition is also linked to increased association of STAT1 with chromatin. The secretion of proteins into the host cell by a type I strain of Toxoplasma without complete parasite invasion is not sufficient to block STAT1-mediated expression, suggesting that the effector protein responsible for this inhibition is not derived from the rhoptries.
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247
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Abstract
The obligate intracellular parasite Toxoplasma gondii is able to infect nearly all nucleated cell types of warm-blooded animals. This is achieved through the injection of hundreds of parasite effectors into the host cell cytosol, allowing the parasite to establish a vacuolar niche for growth, replication, and persistence. Here we show that Toxoplasma infection actives an inflammasome response in mice and rats, an innate immune sensing system designed to survey the host cytosol for foreign components leading to inflammation and cell death. Oral infection with Toxoplasma triggers an inflammasome response that is protective to the host, limiting parasite load and dissemination. Toxoplasma infection is sufficient to generate an inflammasome response in germfree animals. Interleukin 1β (IL-1β) secretion by macrophage requires the effector caspases 1 and 11, the adapter ASC, and NLRP1, the sensor previously described to initiate the inflammasome response to Bacillus anthracis lethal factor. The allele of NLRP1b derived from 129 mice is sufficient to enhance the B6 bone marrow-derived macrophage (BMDM) inflammasome response to Toxoplasma independent of the lethal factor proteolysis site. Moreover, N-terminal processing of NLRP1b, the only mechanism of activation known to date, is not observed in response to Toxoplasma infection. Cumulatively, these data indicate that NLRP1 is an innate immune sensor for Toxoplasma infection, activated via a novel mechanism that corresponds to a host-protective innate immune response to the parasite.
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248
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Zhang AM, Shen Q, Li M, Xu XC, Chen H, Cai YH, Luo QL, Chu DY, Yu L, Du J, Lun ZR, Wang Y, Sha Q, Shen JL. Comparative studies of macrophage-biased responses in mice to infection with Toxoplasma gondii ToxoDB #9 strains of different virulence isolated from China. Parasit Vectors 2013; 6:308. [PMID: 24499603 PMCID: PMC4029513 DOI: 10.1186/1756-3305-6-308] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 10/22/2013] [Indexed: 11/25/2022] Open
Abstract
Background Different from three clonal lineages of Toxoplasma gondii in North America and Europe, the genotype China 1 is predominantly prevalent in China. However, there are different virulent isolates within China 1, such as virulent TgCtwh3 and avirulent TgCtwh6, and little is known about differences in macrophage activation between them. The objective of this study focused on cytokine production, phenotype and markers of activated macrophages, and correlated signaling pathway induced by the two isolates. Methods Adherent peritoneal macrophages (termed Wh3-Mφ and Wh6-Mφ, respectively) harvested from infected mice were cultured for detection of Nitric Oxide and arginase activity, and activated markers on Wh3-Mφ/Wh6-Mφ were determined by flow cytometry. In in vitro experiments, the levels of IL-12p40 and TNF-α were measured using ELISA kits, and mRNA expressions of IL-12p40, TNF-α, iNOS, Arg-1 and Ym1 were assayed by real-time PCR. To confirm the activation state of NF-kB p65 in infected cells stained by IF, protein levels of iNOS, Arg-1, Ym1, nuclear NF-κB p65, and phosphorylation of STAT6/STAT3/IκBα were evaluated by Western Blotting. A one-way ANOVA test was used to compare differences among multiple groups. Results The result revealed that contrary to the virulent TgCtwh3, the less virulent TgCtwh6 isolate induced a significant increase in IL-12p40 and TNF-α. Although both isolates down-regulated CD80, CD86 and MHCII molecule expression on macrophages, TgCtwh3 promoted up-regulation of PD-L2 and CD206. Wh6-Mφ generated a high level of NO whereas Wh3-Mφ up-regulated Ym1 and arginase expression at transcriptional and protein levels. In terms of signaling pathway, TgCtwh3 induced phospho-STAT6, conversely, TgCtWh6 led to NF-κB p65 activation. Conclusions The virulent TgCtwh3 isolate induced macrophages to polarize toward alternatively activated cells with STAT6 phosphorylation, whereas the less virulent TgCtwh6 elicited the development of classically activated macrophages with nuclear translocation of NF-κB p65. This discrepancy suggests that it is necessary to thoroughly analyze the genotype of TgCtwh3 and TgCtwh6, and to further study other effector molecules that contribute to the macrophage polarization in T. gondii.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Quan Sha
- Anhui Provincial Laboratories of Pathogen Biology and Zoonoses, Department of Microbiology and Parasitology, Anhui Medical University, Hefei, Anhui, China.
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249
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Camejo A, Gold DA, Lu D, McFetridge K, Julien L, Yang N, Jensen KDC, Saeij JPJ. Identification of three novel Toxoplasma gondii rhoptry proteins. Int J Parasitol 2013; 44:147-60. [PMID: 24070999 DOI: 10.1016/j.ijpara.2013.08.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 08/06/2013] [Accepted: 08/06/2013] [Indexed: 11/29/2022]
Abstract
The rhoptries are key secretory organelles from apicomplexan parasites that contain proteins involved in invasion and modulation of the host cell. Some rhoptry proteins are restricted to the posterior bulb (ROPs) and others to the anterior neck (RONs). As many rhoptry proteins have been shown to be key players in Toxoplasma invasion and virulence, it is important to identify, understand and characterise the biological function of the components of the rhoptries. In this report, we identified putative novel rhoptry genes by identifying Toxoplasma genes with similar cyclical expression profiles as known rhoptry protein encoding genes. Using this approach we identified two new rhoptry bulb (ROP47 and ROP48) and one new rhoptry neck protein (RON12). ROP47 is secreted and traffics to the host cell nucleus, RON12 was not detected at the moving junction during invasion. Deletion of ROP47 or ROP48 in a type II strain did not show major influence in in vitro growth or virulence in mice.
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Affiliation(s)
- Ana Camejo
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Daniel A Gold
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Diana Lu
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kiva McFetridge
- Department of Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Lindsay Julien
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ninghan Yang
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kirk D C Jensen
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jeroen P J Saeij
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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250
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Braun L, Brenier-Pinchart MP, Yogavel M, Curt-Varesano A, Curt-Bertini RL, Hussain T, Kieffer-Jaquinod S, Coute Y, Pelloux H, Tardieux I, Sharma A, Belrhali H, Bougdour A, Hakimi MA. A Toxoplasma dense granule protein, GRA24, modulates the early immune response to infection by promoting a direct and sustained host p38 MAPK activation. ACTA ACUST UNITED AC 2013; 210:2071-86. [PMID: 24043761 PMCID: PMC3782045 DOI: 10.1084/jem.20130103] [Citation(s) in RCA: 187] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Toxoplasma gondii secretes a novel dense granule protein, GRA24, that traffics from the vacuole to the host cell nucleus where it prolongs p38a activation and correlates with proinflammatory cytokine production. Toxoplasma gondii, the causative agent of toxoplasmosis, is an obligate intracellular protozoan parasite that resides inside a parasitophorous vacuole. During infection, Toxoplasma actively remodels the transcriptome of its hosting cells with profound and coupled impact on the host immune response. We report that Toxoplasma secretes GRA24, a novel dense granule protein which traffics from the vacuole to the host cell nucleus. Once released into the host cell, GRA24 has the unique ability to trigger prolonged autophosphorylation and nuclear translocation of the host cell p38α MAP kinase. This noncanonical kinetics of p38α activation correlates with the up-regulation of the transcription factors Egr-1 and c-Fos and the correlated synthesis of key proinflammatory cytokines, including interleukin-12 and the chemokine MCP-1, both known to control early parasite replication in vivo. Remarkably, the GRA24–p38α complex is defined by peculiar structural features and uncovers a new regulatory signaling path distinct from the MAPK signaling cascade and otherwise commonly activated by stress-related stimuli or various intracellular microbes.
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Affiliation(s)
- Laurence Braun
- Centre National de la Recherche Scientifique (CNRS), UMR5163, Laboratoire Adaptation et Pathogénie des Microorganismes, F-38041 Grenoble, France
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