Project description:Infection of C57BL/6 mice with Plasmodium berghei ANKA (PbA) is a well-established experimental model of cerebral malaria (ECM). ECM is characterised by high levels of parasite sequestration and recruitment of pathogenic CD8+ T cells to the brain. The role of CD4+ T cells in this model has not yet been fully elucidated, although our laboratory has recently shown that CD4+ T cell depletion prior to infection results in significantly lower parasite burdens and protection from ECM. These data highlight a pathogenic role for CD4+ T cells in ECM. Our unpublished observations indicate that mice lacking the CD8+ T cell cytolytic effector molecule, Granzyme B, (GzmB), are resistant to ECM, showing markedly reduced parasite burdens. Late depletion of CD4+ T cells from PbA-infected GzmB-deficient mice results in enhanced parasite burdens, indicating that these cells may play an anti-parasitic role. In the present study, we have analysed splenic CD4+ T cell gene expression profiles in naïve C57BL/6 mice, and PbA-infected wild-type and GzmB-deficent mice to further our understanding of the CD4+ T cell response in ECM. Splenic CD4 T cells isolated by cell sorting from either uninfected C57BL/6 or PbA-infected C57BL/6 or B6.GzmB-/- mice at day 4 post-infection. Total RNA obtained from four mice per group.
Project description:Infection of C57BL/6 mice with Plasmodium berghei ANKA (PbA) is a well-established experimental model of cerebral malaria (ECM). ECM is characterised by high levels of parasite sequestration and recruitment of pathogenic CD8+ T cells to the brain. The role of CD4+ T cells in this model has not yet been fully elucidated, although our laboratory has recently shown that CD4+ T cell depletion prior to infection results in significantly lower parasite burdens and protection from ECM. These data highlight a pathogenic role for CD4+ T cells in ECM. Our unpublished observations indicate that mice lacking the CD8+ T cell cytolytic effector molecule, Granzyme B, (GzmB), are resistant to ECM, showing markedly reduced parasite burdens. Late depletion of CD4+ T cells from PbA-infected GzmB-deficient mice results in enhanced parasite burdens, indicating that these cells may play an anti-parasitic role. In the present study, we have analysed splenic CD4+ T cell gene expression profiles in naïve C57BL/6 mice, and PbA-infected wild-type and GzmB-deficent mice to further our understanding of the CD4+ T cell response in ECM.
Project description:The molecular mechanisms through which dihydroartemisinin (DHA) induces immunomodulation in vivo remain unclear. Herein, DHA-regulated proteins and their phosphorylation profiles were identified and characterized, in the spleens of mice, using proteomics and phosphoproteomic approaches. We found that DHA upregulates proliferation-associated protein (cyclin-dependent kinases, Ki67, and mini-chromosome maintenance and proliferating cell nuclear antigen) expression via modulation of mitogen-activated protein kinase (MAPK) - activator protein 1 (AP-1) signaling pathway activity. In addition, DHA promoted the proliferation of CD4 T naïve, proliferated CD25+CD4+ T-cells, and BrdU+ interferon (IFN)-γ-producing CD8+ T cells. These predicted mechanisms of action were then validated in a Plasmodium berghei ANKA-infected mouse model of malaria and a cyclophosphamide-induced immunosuppression model. Collectively, the findings of this study, for the first time, provide robust evidence that DHA induced the expansion of the splenic T-cell pool through MAPK-AP1 signaling. The data provided in-depth knowledge in the mechanism of DHA-mediated immunomodulation.
Project description:Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection, predominantly experienced by children and non-immune adults, which results in great mortality and long-term sequelae. Recent reports based on histology of post-mortem brain tissue suggest that CM may be the common end point for a range of syndromes. Here, we have analysed the gene expression profiles in brain tissue taken from experimental CM (ECM)-susceptible, Plasmodium berghei ANKA (PbA)-infected C57BL/6 (B6) and CBA/CaH (CBA) mice with ECM. Gene expression profiles were largely heterogeneous between the two ECM-susceptible strains. These results, combined with experimental data, support the existence of distinct pathogenic pathways in CM. Keywords: disease state analysis
Project description:Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection, predominantly experienced by children and non-immune adults, which results in great mortality and long-term sequelae. Recent reports based on histology of post-mortem brain tissue suggest that CM may be the common end point for a range of syndromes. Here, we have analysed the gene expression profiles in brain tissue taken from experimental CM (ECM)-susceptible, Plasmodium berghei ANKA (PbA)-infected C57BL/6 (B6) and CBA/CaH (CBA) mice with ECM. Gene expression profiles were largely heterogeneous between the two ECM-susceptible strains. These results, combined with experimental data, support the existence of distinct pathogenic pathways in CM. Experiment Overall Design: C57BL/6 and CBA/CaH mice were infected with 10e5 Plasmodium berghei ANKA-infected RBCs and monitored for ECM development. At onset of ECM symptoms, infected mice and naive controls were culled, perfused (in order to remove non-adherent circulating cells), and brains were removed. Total RNA was extracted from these brains and pooled (n=6 mice/ group). Pooled RNA samples were converted to cDNA and antisense cRNA, labelled and hybridized to GeneChip Mouse Genome 430 2.0 Arrays (Affymetrix, Surrey Hills, Australia). Arrays were scanned using the GeneChip Scanner 3000 (Affymetrix) and GeneChip Operating Software v1.1.1 (Affymetrix). Normalisation and initial analyses were carried out in GeneSpring v7 (Agilent Technologies). Values below 0.01 were set to 0.01. Each measurement was divided by the 50th percentile of all measurements in that sample. The data was filtered for genes flagged as present, which had at least an expression level of 50. Following this, a threshold of 2.5 fold up-regulation or down-regulation of genes differentially expressed during ECM was set.
Project description:Cerebral Malaria (CM), the deadliest complication of Plasmodium infection, is a complex and unpredictable disease. Currently, our understanding of the factors that trigger progression of malaria to CM is limited. Here, by infecting experimental CM (ECM) resistant (Balb/c) and ECM susceptible (C57BL/6) mice with ECM causing (ANKA) and non-ECM causing (NK65) Plasmodium berghei (Pb) parasite strains, we revealed that in resistant host, infection by ECM causing parasite develops similar to infection by non-ECM causing parasite in susceptible host in terms of parasite growth in host, disease course and host immune response against parasite. Our comparative gene expression analysis revealed that in Balb/c host, gene expression of Pb ANKA parasite is remarkably different from, the gene expression of Pb ANKA in C57BL/6 but similar to the gene expression of non-ECM causing Pb NK65 in C57BL/6. Thus, host has a critical influence on parasite behavior which ultimately determines the course of malaria disease.
Project description:Gene expression patterns were investigated in well-defined genetically cerebral malaria-resistant (CM-R) and cerebral malaria-susceptible (CM-S) mouse strains. cDNA microarrays were used to search for differentially expressed genes in mouse brain. Four mouse strains, known to differ in susceptibility to cerebral malaria upon Plasmodium berghei ANKA infection, were compared: BALB/c and DBA/2 mice are CM-R, while C57BL/6 and CBA/J mice are CM-S.
Project description:Plasmodium berghei transcriptomes of wild-type ANKA (WT) and garid knockout parasites [garid(-)] were analyzed at the gametocyte stage.