Project description:A major mental illness-related susceptibility factor, Disrupted in schizophrenia (DISC1), is involved in altered host immune responses against Toxoplasma gondii (T. gondii) infection. Specifically, our gene expression studies have revealed that DISC1 Leu607Phe variation, which changes DISC1 interaction with activating transcription factor 4 (ATF4), modifies gene expression patterns upon T. gondii infection.
Project description:The closely related protozoan parasites Toxoplasma gondii and Neospora caninum display similar life cycles, subcellular ultrastructure, invasion mechanisms, metabolic pathways, and genome organization, but differ in their host range and disease pathogenesis. Type II (?) interferon has long been known to be the major mediator of innate and adaptive immunity to Toxoplasma infection, but genome-wide expression profiling of infected host cells indicates that Neospora is a potent activator of the type I (?/?) interferon pathways typically associated with antiviral responses. Infection of macrophages from mice with targeted deletions in various innate sensing genes demonstrates that host responses to Neospora are dependent on the toll-like receptor Tlr3 and the adapter protein Trif. Consistent with this observation, RNA from Neospora elicits type I interferon responses when targeted to the host endo-lysosomal system. While live Toxoplasma fails to induce type I interferon, heat-killed parasites do trigger this response, and co-infection studies reveal that T. gondii actively suppresses the production of type I interferon. These findings reveal that eukaryotic pathogens can be potent inducers of type I interferon and that some parasite species, like Toxoplasma gondii, have evolved mechanisms to suppress this response. In vitro cultures of bone marrow-derived macrophages from WT or IFNAR2-/- mice were infected with either Toxoplasma gondii (VEG strain) or Neospora caninum (Nc2 strain) for 17 hours. RNA was collected from biological replicates for expression profiling by microarray. Uninfected controls for both WT and IFNAR2-/- were used as a reference.
Project description:The closely related protozoan parasites Toxoplasma gondii and Neospora caninum display similar life cycles, subcellular ultrastructure, invasion mechanisms, metabolic pathways, and genome organization, but differ in their host range and disease pathogenesis. Type II (γ) interferon has long been known to be the major mediator of innate and adaptive immunity to Toxoplasma infection, but genome-wide expression profiling of infected host cells indicates that Neospora is a potent activator of the type I (α/β) interferon pathways typically associated with antiviral responses. Infection of macrophages from mice with targeted deletions in various innate sensing genes demonstrates that host responses to Neospora are dependent on the toll-like receptor Tlr3 and the adapter protein Trif. Consistent with this observation, RNA from Neospora elicits type I interferon responses when targeted to the host endo-lysosomal system. While live Toxoplasma fails to induce type I interferon, heat-killed parasites do trigger this response, and co-infection studies reveal that T. gondii actively suppresses the production of type I interferon. These findings reveal that eukaryotic pathogens can be potent inducers of type I interferon and that some parasite species, like Toxoplasma gondii, have evolved mechanisms to suppress this response. Human foreskin fibroblasts (HFF; line BJ-5ta) were cultured to confluency in T25 flasks, infected with one representative of each of the three architypial strains of Toxoplasma gondii: GT1 (type I), Prugniaud (type II) and VEG (type III), or the closely related parasite species, Neospora caninum (strain Nc-Liv). RNA was collected from biological replicates for expression profiling by microarray. Uninfected HFF cells were used as a reference.
Project description:The spleen is a site of acute infection following challenge with the parasite Toxoplasma gondii. We utilized scRNA sequencing to analyze the immune response to this infection.
Project description:The outcome of infections with Toxoplasma gondii in humans is dependent in part on the genetic makeup of the infecting organism. Recent studies have indicated that most infecting Toxoplasma organisms fall into 1 of 3 canonical lineages. Previous studies have investigated the effects of Toxoplasma on its host cell transcriptome. Little is known, however, about the effects of three canonical lineages on brain cells, the principal site of parasite lifelong persistence. In this study, we examined the transcriptional profile of human neuroepithelioma cells in response to T. gondii infection using microarray analysis to characterize the strain-specific host cell response to 3 canonical T. gondii strains. We found that the extent of the expression changes varied considerably among the three strains. Neuroepithelial cells infected with type I exhibited the most differential gene expression, whereas type II infected cells had a substantially smaller number of genes which were differentially expressed. Cells infected with type III exhibited intermediate effects on gene expression. The three strains also differed in the individual genes and gene pathways which were altered following cellular infection. For example, gene ontology (GO) analysis indicated that type I infection largely affects genes related to central nervous system while type III infection largely alters genes which affect nucleotide metabolism; type II infection does not alter expression of a clearly defined set of genes. Moreover, Ingenuity pathway analysis (IPA) revealed the sophistication of different strain in its interactions with the host. These differences may explain some of the variation in the neurobiological effects of different strains of Toxoplasma on infected individuals. We infected SK-N-MC cells with 3 canonical Toxoplasma strains and assessed their gene expression in RNA at 20 hours post-infection using Affymetrix GeneChip. Infections and controls (no tachyzoites) were performed in duplicate and experiments for each strain were carried out on three separate occasions in order to include both technical replicates and biological replicates.
Project description:The outcome of infections with Toxoplasma gondii in humans is dependent in part on the genetic makeup of the infecting organism. Recent studies have indicated that most infecting Toxoplasma organisms fall into 1 of 3 canonical lineages. Previous studies have investigated the effects of Toxoplasma on its host cell transcriptome. Little is known, however, about the effects of three canonical lineages on brain cells, the principal site of parasite lifelong persistence. In this study, we examined the transcriptional profile of human neuroepithelioma cells in response to T. gondii infection using microarray analysis to characterize the strain-specific host cell response to 3 canonical T. gondii strains. We found that the extent of the expression changes varied considerably among the three strains. Neuroepithelial cells infected with type I exhibited the most differential gene expression, whereas type II infected cells had a substantially smaller number of genes which were differentially expressed. Cells infected with type III exhibited intermediate effects on gene expression. The three strains also differed in the individual genes and gene pathways which were altered following cellular infection. For example, gene ontology (GO) analysis indicated that type I infection largely affects genes related to central nervous system while type III infection largely alters genes which affect nucleotide metabolism; type II infection does not alter expression of a clearly defined set of genes. Moreover, Ingenuity pathway analysis (IPA) revealed the sophistication of different strain in its interactions with the host. These differences may explain some of the variation in the neurobiological effects of different strains of Toxoplasma on infected individuals.
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. Chicken embryonic fibroblasts were cultivated in vitro and infected with different strains of Toxoplasma gondii; host transcriptional responses were then analyzed at 24 hours post-infection.
Project description:Toxoplasma gondii (T. gondii) is an opportunistic parasite. After infection, macrophages finely regulate the immune response to restrict parasite proliferation. It is well-known that N6-methyladenosine (m6A) plays a critical role in fine-tuning gene expression. To investigate whether m6A modification is involved in regulating the anti-infection immune response in macrophages against T. gondii, this study utilized T. gondii tachyzoites from the RH strain to infect human THP-1 macrophages. qPCR and ELISA results showed that T. gondii infection mounted the expression of TNF-α. RNA-seq profiling showed that T. gondii infection was associated with difference in genes from pathway associated with TNF signaling. Expression of m6A regulators were evaluated using qPCR and Western blotting. T. gondii infection increased the abundance of m6A methyltransferase WTAP and demethylase FTO. Joint analysis of RNA-seq and m6A-seq data was utilized for enriching differentially expressed genes with significantly altered m6A modifications. After T. gondii infection, the m6A levels of genes associated with TNF signaling were significantly altered. In this study, we found that m6A methylation involved in T. gondii infection induced TNF-α expression.
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