Project description:Malaria parasites go through major transitions during their complex life cycle, yet the underlying differentiation pathways remain obscure. Here we apply single cell transcriptomics to unravel events that initiate sexual development in preparation for transmission of the parasite from human to mosquito. This proof-of-concept study provides a template to capture transcriptional diversity in heterogeneous parasite populations, with major implications for our understanding of parasite biology and the ongoing malaria elimination campaign.
Project description:This experiment characterizes the transcriptome of the human malaria parasite, P. falciparum at 8 different stages of the intraerythrocytic cycle
Project description:The pathogenesis of severe malaria is complex and involves several pathways that influence host inflammation and endothelial function. The human malaria parasite Plasmodium falciparum is responsible for the majority of mortality and morbidity caused by malaria infection and differs from other human malaria species in the degree of accumulation of parasite-infected red blood cells in the microvasculature, known as cytoadherence or sequestration. In P. falciparum, cytoadherence is mediated by a protein called PfEMP1 which, due to its exposure to the host immune system, undergoes antigenic variation resulting in the expression of different PfEMP1 variants on the infected erythrocyte membrane. These PfEMP1s contain various combinations of adhesive domains, which allow for the differential engagement of a repertoire of endothelial receptors on the host microvasculature, with specific receptor usage associated with severe disease. Cytoadherence results in perturbation of the micro-circulation as well as direct effects on endothelial cells promoted by receptor-mediated signalling. We used a co-culture model of cytoadherence incubating human brain microvascular endothelial cells with erythrocytes infected with two parasite lines expressing different PfEMP1s; IT4var14 (long-form; ups B) that binds strongly to human brain microvascular endothelial cells mainly via ICAM-1, and IT4var 37 (short-form; ups C) that does not bind brain endothelium but shows high levels of binding to human dermal microvascular endothelial cells via CD36. We determined the transcriptional profile of the endothelial cells following different incubation periods with infected erythrocytes, identifying different transcriptional profiles of pathways involved in the pathology of severe malaria, such as inflammation, apoptosis and barrier integrity, induced by the two PfEMP1 variants.
Project description:During malaria infection is observed a robust immune response culminating on release of inflammatory mediators. This exacerbated immune response is involved in malaria symptoms and mortality. There are evidences that this response is mediated by innate immunity where pattern recognition receptors have a key role. We used microarrays to elucidate some pro-inflammatory genes that are differential expressed during P. chabaudi infection, a malarial murine model Spleen from C57BL/6 or MyD88 knockout mice non-infected or after 6 days post infection with 105 P. chabaudi infected red blood cells were harvested for RNA extraction and hybridization on Affymetrix microarrays. This time point was chose to coincides with rupture of red blood cells \since this event of the parasite life cycle is related with malaria outcomes.
Project description:This experiment characterizes the localisation of H2A.Z, H3K9ac and H3K4me3 in the epigenome of the human malaria parasite, P. falciparum at 4 different stages of intraerythrocytic development.
Project description:Background: The mosquito Anopheles gambiae is a major vector of human malaria. Increasing evidence indicates that blood cells (hemocytes) comprise an essential arm of the mosquito innate immune response against both bacteria and malaria parasites. To further characterize the role of hemocytes in mosquito immunity, we undertook the first genome-wide transcriptomic analyses of adult female An. gambiae hemocytes following infection by two species of bacteria and a malaria parasite. Results: We identified 4047 genes expressed in hemocytes, using An. gambiae genome-wide microarrays. While 279 transcripts were significantly enriched in hemocytes relative to whole adult female mosquitoes, 959 transcripts exhibited immune challenge-related regulation. The global transcriptomic responses of hemocytes to challenge with different species of bacteria and/or different stages of malaria parasite infection revealed discrete, minimally overlapping, pathogen-specific signatures of infection-responsive gene expression; 105 of these represented putative immunity-related genes including anti-Plasmodium factors. Of particular interest was the specific co-regulation of various members of the Imd and JNK immune signaling pathways during malaria parasite invasion of the mosquito midgut epithelium. Conclusion: Our genome-wide transcriptomic analysis of adult mosquito hemocytes reveals pathogen-specific signatures of gene regulation and identifies several novel candidate genes for future functional studies.