Project description:We hypothesize that human malarial infection will result in a global transcriptomic alteration which will depend upon the strain of invading Plasmodium pathogen.
Project description:Disease tolerance is an alternative strategy for acquired immunity to malaria and can be rapidly induced after a single malaria episode - in the absence of improved parasite clearance. Memory of a first malaria episode dampens the inflammatory profile of spleen monocytes and induces mechanisms of stress tolerance to minimise tissue damage. This begs the question how monocytes are instructed to respond in a different way to second compared to first malaria infection. We asked if malaria alters the epigenetic landscape of inflammatory monocytes before their release from the bone marrow - thus testing the compelling innate memory hypothesis. We compared the genome-wide distribution of histone modifications on flow-sorted bone marrow monocytes from mice with memory of severe mosquito transmitted P. chabaudi AJ infection (30 days after drug cure) and drug treated uninfected age-matched controls using ChIPseq. Specifically, we tested whether once-infected mice have long-lived modifications in i) transcription start sites marked with H3K27ac to activate transcription ii) enhancers or superenhancers marked with H3K4me1 to promote gene expression and iii) in H3K9me3 to condense DNA into heterochromatin thereby silencing gene expression. We found no meaningful differences in the histone modification profiles of 2848 genes that define monocyte function in first and second malaria infection using the motif discovery software HOMER. Furthermore, when calling differentially modified regions (DMR) between once-infected mice and uninfected mice to ask whether there were any measurable differences in the epigenetic landscapes of these genes, we found 95% had no detectable modifications. In those rare cases where a DMR was called, HOMER assigned a low peak score, indicating low confidence and minimal biological relevance. Epigenetic reprogramming does therefore not underpin the functional specialisation of inflammatory monocytes in tolerised hosts. Innate memory is thus not induced by malaria infection in vivo. Instead, altered monocyte function and fate are imprinted within the spleen (link to GEO microarray) to promote disease tolerance.
Project description:Whole blood transcriptomes from a longitudinal study of 5 Malawian children who first present with severe Plasmodium falciparum malaria, and return in one month with mild malaria We used microarrays to identify transcripts that were associated with each clinical presentation. A blood sample was taken upon presentation during the severe and mild malaria episodes in 5 Malawian children (total n=5 pairs) followed by RNA extraction and hybridization on Affymetrix GeneChip Human Gene 1.0 ST Array, using a paired analysis
Project description:The number of patients infected with simian malaria is increasing in many countries in Southeast Asia. The behavior of humans, monkeys, and vectors influences their interactions with each other and is the most important risk factor of zoonotic malaria infection. However, no serum proteomics study has been conducted in wild macaques. The present study was performed using a proteomics approach to explore the protein expression profile of wild stump-tailed macaques (Macaca arctoides) infected with malaria parasites.
Project description:Using genome-wide expression profiles from persons either experimentally challenged with malaria-infected mosquitoes or naturally-infected with Plasmodium falciparum malaria, we present details of the transcriptional changes that occur with infection and that are either commonly shared between subjects with pre-symptomatic and clinically apparent malaria or that distinguish these two groups. Our findings confirm and extend aspects of the earliest responses to malaria infection at the molecular level and which may be informative in elucidating how innate and adaptive immune responses may be modulated in different stages of infection. Keywords: Human PBMC samples from natural and experimentally (clinical trial) induced malaria
Project description:Falciparum malaria is clinically heterogeneous and the relative contribution of parasite and host in shaping disease severity remains unclear. We explored the interaction between inflammation and parasite variant surface antigen (VSA) expression, asking whether this relationship underpins the variation observed in controlled human malaria infection (CHMI). We uncovered marked heterogeneity in the host response to blood challenge; some volunteers remained quiescent, others triggered interferon-stimulated inflammation and some showed transcriptional evidence of myeloid cell suppression. Significantly, only inflammatory volunteers experienced hallmark symptoms of malaria. When we tracked temporal changes in parasite VSA expression to ask whether variants associated with severe disease rapidly expand in naive hosts, we found no transcriptional evidence to support this hypothesis. These data indicate that parasite variants that dominate severe malaria do not have an intrinsic growth or survival advantage; instead, they presumably rely upon infection-induced changes in their within-host environment for selection.
Project description:We aimed at finding differently expressed genes in whole blood cells of African children with asymptomatic Plasmodium falciparum infection (A), uncomplicated malaria (U), severe malarial anemia (A) and cerebral malaria (Ce) compared one to another and to healthy children (Co). Understanding malarial immunopathology in the human host represents and enormous challenge for transcriptomic research. In this work, we used microarray and real-time RT-PCR technology to pursue deeper knowledge about the mechanisms underlying this disease in African children. To this end, we investigated the genomic transcriptional profiles in whole blood of healthy children and children with asymptomatic infection, uncomplicated malaria, malaria associated with severe anemia and cerebral malaria and compared them with previously published microarray results. We were able to discriminate between the different presentations of P. falciparum infection using supervised and unsupervised clustering of microarray data and unsupervised double-hierarchical clustering of real-time RT-PCR results of a set of 22 genes known to be expressed in at least one of the principal blood cell lineages. We further found considerable overlap between genes regulated in Kenyan and Gabonese children with symptomatic malaria, in contrast to adults with acute malaria from Cameroon. Different signatures for transcription factor binding sites in promoters of genes either up-regulated in symptomatic disease, specifically up-regulated in uncomplicated malaria or specifically down-regulated in cerebral malaria point out that similar gene expression in each of these clinical presentations is probably a result of common regulation at the transcriptional level. Immunoglobulin production, complement regulation and IFN beta signalling emerged as most discrepant features between uncomplicated malaria and all other investigated presentations, correlating with IRF7 and ISRE binding signatures in the corresponding genes. Down-regulation of several genes in cerebral malaria seems instead to be a response to hypoxia orchestrated by AhRF, GABP and HIF1 transcription factors. ARG1, BPI, CD163, IFI27, HP and TNFAIP6 transcript levels correlated positively with lactatemia and inversely with hemoglobin concentration and should be evaluated as prognostic markers to direct early therapeutic measures and prevent malarial disease evolution and death.
Project description:Acute malaria infection with P. chabaudi obliterates embryonically seeded tissue-resident red pulp macrophages in the spleen of C57Bl/6J mice - regardless of whether the infection is mild (mosquito transmitted P. chabaudi AS - no hyperparasitaemia, no measurable clinical manifestations of disease other than low-grade anaemia) or severe (mosquito transmitted P. chabaudi AJ - acute hyperparasitaemia, severe anaemia, hypothermia and prostration). Red pulp macrophages return 100 days later, once mice cleared parasitaemia. We then flow sorted 10,000 red pulp macrophages (lineage-, autofluorescent, F4/80+, B220-, CD11bint, CD11cint) directly into Trizol, extracted total RNA and analysed their transciptome using the affymetrix mouse exon 1.0 ST array. Red pulp macrophages from mice once infected with mild AS or severe AJ P. chabaudi parasites were compared to uninfected age-matched mice. We uncover that red pulp macrophages isolated from the spleens of once-malaria infected mice are transcriptionally identical to prenatally seeded red pulp macrophages from uninfected mice. The spleen tissue niche thus imprints an identical functional profile onto these cells - regardless of their origin.
Project description:During liver infection, the malaria parasite undergoes massive replication whilst remaining clinically silent. Spatial coordination of immune response regulation and metabolic zonation during malaria infection in the true tissue context remains unexplored. We perform spatial transcriptomics combined with snRNA-seq over multiple time points to delineate transcriptional programs of host-pathogen interactions across P. berghei-infected liver tissues. Our data suggest changes in gene expression related to lipid metabolism adjacent to infected hepatocytes, particularly modulation of the expression of genes involved in peroxisome proliferator-activated receptor pathway signaling. The data further indicates the presence of inflammatory hotspots with differential inflammation programs along the lobular axis in infected tissues. Additionally, upregulation of genes involved in inflammation is observed, but considerably delayed, in livers of control mice injected with mosquito salivary gland components. Our study establishes a benchmark for investigating host-parasite interactions, and can easily be implemented to validate de novo malaria drug and vaccine efforts.