Project description:To identify accessible chromatin regions in the human host cells during Toxoplasma parasite infection (uninfected, RH-infected and Pru-infected human foreskin fibroblasts) and in the obligate intracellular parasite Toxoplasma gondii (Type 1 RH strain and Type 2 Pru strain), ATAC-seq was performed.
Project description:Toxoplasma gondii (T. gondii) is an obligate intracellular parasite that can infect almost all warm-blooded animals, causing serious public health problems. Lysine crotonylation (Kcr) is a newly discovered posttranslational modification (PTM), which has been proved that is relevant to procreation regulation, active transcription and cell signaling pathway. However, the biological functions of crotonylation have not yet been reported in macrophages infected with T. gondii. In our study, we performed a ChIP-seq analysis of porcine alveolar macrophages infected with T. gondii RH to explore the relationship of histone Kcr with T. gondii infection.
Project description:The normally virulent type-I RH parasite is rendered avirulent when lacking ROP5. The avirulent phenotype is a consequence of interaction with the host innate immune system. We sought to understand if ROP5 alters host gene expression in order to escape host defenses. We saw no gene expression differences between host cells infected with wt (RH?ku80) or RH?ku80?rop5 parasites. We have included uninfected HFF samples that were harvested in parallel with the infected samples. Host gene expression in response to infection with Toxoplasma gondii. Two independent samples per sample type. Three sample types: HFF infected with RH?ku80, HFF infected with RH?ku80?rop5, and uninfected HFF.
Project description:Toxoplasma gondii is a globally distributed obligate intracellular parasite which can cause zoonotic toxoplasmosis with great harms. The average death time of mice that infected with Toxoplasma gondii RH strain tachyzoites recovered from the liquid nitrogen was shortened after multiple generations. It has been reported that the parasite is in a state of static virulence during cryopreservation and the virulence of the protozoan parasite can be enhanced after continuous passages in hosts under laboratory conditions. However, no research has been conducted to elucidate its biological mechanism. Herein, we sequenced the T. gondii transcriptome using RNA-Seq technology and performed de novo assembly to investigated the virulence factors expression changes by comparing gene expression profiles between incipiently recovered and completely resuscitated tachyzoites. Transcriptome analysis identified 1,951 differentially expressed transcripts in infected liver, of which 1,752 were significantly downregulated and 199 upregulated. We identified many differentially expressed proteins and genes, including serine/threonine kinase, calnexin, myosin and microtubule-associated protein which have previously been reported to be either involved in cell adhesion, parasite gliding or participate in cell invasion. The great majority of the virulence factors including microneme proteins, rhoptry proteins and dense granule proteins were upregulated in fully recovered tachyzoites. The enhanced virulence of recovered Toxoplasma gondii RH strain from the liquid nitrogen is associated with the up-regulated expression of MICs, ROPs and GRAs. Our data will facilitate future genomic research and in-depth annotation of Toxoplasma gondii RH strain genomes. This study provides a profile of the candidate genes that are suspected to be involved with virulence enhancement of recovered Toxoplasma gondii RH strain tachyzoites. Many further studies should be carried out to confirm the function of the candidate genes. Moreover, the preliminary identification of genes and pathways exhibiting differential expression in complete resuscitation stage may further our general understanding of virulence enhancement in this parasite.
Project description:Parasite gene expression differences have been reported previously between RH-ERP, RH-JSR and GT1. To independently confirm these gene expression differences, we examined the parasite gene expression profiles of RH-ERP, RH-JSR and GT1 through microarray. Three type I strains of Toxoplasma gondii were compared with one array each, and these were used to verify data from previous studies.
Project description:Toxoplasma gondii is a ubiquitous protozoan pathogen able to infect both mammalian and avian hosts. Surprisingly, just three strains appear to account for the majority of isolates from Europe and N. America. To test the hypothesis that strain divergence might be driven by differences between mammalian and avian response to infection, we examine in vitro strain-dependent host responses in a representative avian host, the chicken. To identify parasite drivers of strain-dependent host response, QTL mapping was used; analysis revealed a locus on Toxoplasma chromosome VIIb. To determine whether this was the parasite gene ROP16, array analysis was performed on chicken embryonic fibroblasts infected with Type I parasites and ROP16-KO parasites (of a Type I background). Chicken embryonic fibroblasts were cultivated in vitro and infected with either Type I (RH) parasites or Type I ROP16-KO parasites; ROP16-dependent host transcriptional responses were then analyzed at 5 hours post-infection.
Project description:Type I strains of Toxoplasma gondii exhibit phenotypic variation, but it is uncertain how differently type I strains modulate the host cell. We determined differential host modulation by type I strains through microarray. HFFs were infected with RH-ERP, RH-JSR and GT1 for 24 hours. Total RNA was isolated and hybridized to Affymetrix GeneChip Human Genome U133A 2.0 arrays.
Project description:The in vitro effect of infection with different strains of Toxoplasma gondii was tested 24 hours after infection of Human Foreskin Fibroblasts (HFF) The strains tested include RH, VEG, and transgenic strains of RH overexpressing ROP38 or ROP21 Total RNA of Toxoplasma gondii infected HFF cell was compared to uninfected cells
Project description:Toxoplasma gondii is an obligate intracellular Apicomplexan parasite capable of invading and surviving within nucleated cells in most warm-blooded animals. This remarkable task is achieved through the delivery of effector proteins from the parasite into the parasitophorous vacuole and host cell cytosol that rewire host cellular pathways, facilitating parasite evasion of the immune system. Here, we have identified a novel export pathway in Toxoplasma that involves cleavage of effector proteins by the Golgi-resident aspartyl protease 5 (ASP5) prior to translocation into the host cell. We demonstrate that ASP5 cleaves a highly constrained amino acid motif that has some similarity to the PEXEL motif of Plasmodium parasites. We show that ASP5 can mature effectors at both the N- and C-terminal ends of proteins and is also required for the trafficking of proteins without this motif. Furthermore, we show that ASP5 controls establishment of the nanotubular network and is required for the efficient recruitment of host mitochondria to the parasitophorous vacuole membrane. Global assessment of host gene expression following infection reveals that ASP5-dependent pathways influence thousands of the transcriptional changes that Toxoplasma imparts on its host cell. This work characterizes the first identified machinery required for export of Toxoplasma effectors into the infected host cell. Three groups of human foreskin fibroblasts are compared. Each group has 3 replicates giving a total of 9 samples. The first group of samples are infected with wild type (GRA16HA) Toxoplasma gondii, the second group with Asp5 knock-out Toxoplasma gondii, and the final group remain uninfected. All fibroblasts are generated from one donor sample.