Stem cell technology provides novel tools to understand the impact of human variation on malaria
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE245735 | GEO | 2023/10/21
REPOSITORIES: GEO
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Project description:The role of infection in erythropoietic dysfunction is poorly understood. In children with P. falciparum malaria, the by-product of hemoglobin digestion in infected red cells (hemozoin) is associated with the severity of anemia which is independent of circulating levels of the inflammatory cytokine tumor necrosis alpha (TNF-alpha). To gain insight into the common and specific effects of TNF-alpha and hemozoin on erythropoiesis, we studied the gene expression profile of purified primary erythroid cultures exposed to either TNF-alpha (10ng/ml) or to hemozoin (12.5microgram/ml heme units) for 24 hours. Perturbed gene function was assessed using co-annotation of associated gene ontologies and expression of selected genes representative of the profile observed was confirmed by real time PCR (rtPCR). The changes in gene expression induced by each agent were largely distinct; many of the genes significantly modulated by TNF-alpha were not affected by hemozoin. The genes modulated by TNF-alpha were significantly enriched for those encoding proteins involved in the control of type 1 interferon signalling and the immune response to viral infection. In contrast, genes induced by hemozoin were significantly enriched for functional roles in regulation of transcription and apoptosis. Further analyses by rtPCR revealed that hemozoin increases expression of transcription factors that form part of the integrated stress response which is accompanied by reduced expression of genes involved in DNA repair. This study confirms that hemozoin induces cellular stress on erythroblasts that is additional to and distinct from responses to inflammatory cytokines and identifies new genes that may be involved in the pathogenesis of severe malarial anemia. More generally the respective transcription profiles highlight the varied mechanisms through which erythropoiesis may be disrupted during infectious disease. Erythroblasts derived from PBMCs were enriched to 97% purity for proerythroblast and intermediate/normoblast phases of differentiation using magnetic bead isolation. There were three treatment groups: media, P.falciparum hemozoin (12.5 microgram /ml hematin units) and tumour necrosis factor alpha(10ng/ml). Total RNA using 7.5 x105 cells per treatment from one donor was extracted using Trizol. Highly significant gene ontological findings (where p> x10^-17 but < x10^-7) were confirmed by quantitative PCR.
2015-02-04 | E-GEOD-65577 | biostudies-arrayexpress
Project description:The role of infection in erythropoietic dysfunction is poorly understood. In children with P. falciparum malaria, the by-product of hemoglobin digestion in infected red cells (hemozoin) is associated with the severity of anemia which is independent of circulating levels of the inflammatory cytokine tumor necrosis alpha (TNF-alpha). To gain insight into the common and specific effects of TNF-alpha and hemozoin on erythropoiesis, we studied the gene expression profile of purified primary erythroid cultures exposed to either TNF-alpha (10ng/ml) or to hemozoin (12.5microgram/ml heme units) for 24 hours. Perturbed gene function was assessed using co-annotation of associated gene ontologies and expression of selected genes representative of the profile observed was confirmed by real time PCR (rtPCR). The changes in gene expression induced by each agent were largely distinct; many of the genes significantly modulated by TNF-alpha were not affected by hemozoin. The genes modulated by TNF-alpha were significantly enriched for those encoding proteins involved in the control of type 1 interferon signalling and the immune response to viral infection. In contrast, genes induced by hemozoin were significantly enriched for functional roles in regulation of transcription and apoptosis. Further analyses by rtPCR revealed that hemozoin increases expression of transcription factors that form part of the integrated stress response which is accompanied by reduced expression of genes involved in DNA repair. This study confirms that hemozoin induces cellular stress on erythroblasts that is additional to and distinct from responses to inflammatory cytokines and identifies new genes that may be involved in the pathogenesis of severe malarial anemia. More generally the respective transcription profiles highlight the varied mechanisms through which erythropoiesis may be disrupted during infectious disease.
2015-02-04 | GSE65577 | GEO
Project description:Cerebral malaria (CM), the most lethal complication of Plasmodium falciparum severe malaria (SM), claims the life of 15 to 25% of admitted children despite treatment. P. falciparum infects and multiplies in human erythrocytes, contributing to anemia, parasite sequestration, and inflammation in the host. In this study, an unbiased proteomic assessment of infected erythrocytes and plasma samples from 24 Beninese children was performed to decipher the complex mechanisms underlying the pathophysiology of CM and the corresponding host-parasite interactions. A significant down-regulation of proteins from the ubiquitin-proteasome pathway and an up-regulation of the erythroid precursor marker transferrin receptor protein 1 (TFRC) was associated with infected erythrocytes from CM patients. Further functional analysis showed dysregulated iron metabolism and ferroptosis pathways associated with CM. At the plasma level, the samples clustered according to clinical presentation. Importantly, increased levels of the 20S proteasome components were associated with SM. Targeted quantification assays confirmed these findings on a larger confirmation cohort (n=274). These findings suggest that parasites causing CM preferentially infect reticulocytes or erythroid precursors and alter their maturation. Importantly, the host plasma proteome serves as a specific signature of SM and presents a remarkable opportunity for developing innovative diagnostic and prognostic biomarkers.
2024-02-01 | PXD043033 | Pride
Project description:Pathology of the most lethal form of malaria is caused by Plasmodium falciparum asexual blood stages and initiated by merozoite invasion of erythrocytes. We present a phosphoproteome analysis of extracellular merozoites revealing 1765 unique phosphorylation sites including 785 sites not previously detected in schizonts
2015-04-23 | PXD001684 | Pride
Project description:Cerebral malaria is a multifactorial condition that begins with high numbers of infected erythrocytes binding to human brain endothelium without invasion into the brain. Here we investigated the global transcriptional gene response of primary human brain endothelial cells after incubation with high numbers of infected erythrocytes; High or low parasite binding phenotypes did not alter gene response. Predominate amongst signaling pathways were the NF-kB proinflammatory response. The inflammatory pathways were validated by direct measurement of proteins. This study delineates the strong inflammatory component of human brain endothelium contributing to cerebral malaria. Experiment Overall Design: Total of 8 samples (4 control and 4 treated) were analyzed. 4 control samples included two normal RBC control and two medium controls. 4 treated samples includes 2 exposed to low binding Pf-IRBC and 2 exposed to high binding Pf-IRBC (Pf-IRBC-P). Medium and RBC controls were finally used as four replicates of control and all four Pf-IRBC or Pf-IRBC-P exposed endothelial cells were used as 4 separate treated controls.
2009-01-13 | E-GEOD-9861 | biostudies-arrayexpress
Project description:Ring-infected erythrocytes are the predominant asexual stage in the peripheral circulation but are rarely investigated in the context of acquired immunity against Plasmodium falciparum malaria. Here we compare antibody-dependent phagocytosis of ring-infected parasite cultures in samples from a controlled human malaria infection (CHMI) study (NCT02739763). Protected volunteers did not develop clinical symptoms, maintained parasitaemia below a predefined threshold of 500 parasites/μl and were not treated until the end of the study. Antibody-dependent phagocytosis of both ring-infected and uninfected erythrocytes from parasite cultures was strongly correlated with protection. A surface proteomic analysis revealed the presence of merozoite proteins including erythrocyte binding antigen-175 and -140 on ring-infected and uninfected erythrocytes, providing an additional antibody-mediated protective mechanism for their activity beyond invasion-inhibition. Competition phagocytosis assays support the hypothesis that merozoite antigens are the key mediators of this functional activity. Targeting ring-stage parasites may contribute to the control of parasitaemia and prevention of clinical malaria.
2022-08-11 | PXD033964 | Pride
Project description:Central to the pathology of malaria disease are the repeated cycles of parasite invasion and destruction of human erythrocytes. In Plasmodium falciparum, the most virulent species causing malaria, erythrocyte invasion involves several specific receptor–ligand interactions that direct the pathway used to invade the host cell, with parasites varying in their dependency on these different pathways. Gene disruption of a key invasion ligand in the 3D7 parasite strain, the P. falciparum reticulocyte binding-like homolog 2b (PfRh2b), resulted in the parasite invading via a novel pathway. Here, we show results that suggest the molecular basis for this novel pathway is not due to a molecular switch but is instead mediated by the redeployment of machinery already present in the parent parasite but masked by the dominant role of PfRh2b. This would suggest that interactions directing invasion are organized hierarchically, where silencing of dominant invasion ligands reveal underlying alternative pathways. This provides wild parasites with the ability to adapt to immune-mediated selection or polymorphism in erythrocyte receptors and has implications for the use of invasion-related molecules in candidate vaccines. Keywords: genetic modification
2005-12-21 | GSE3877 | GEO
Project description:Malaria in pregnancy remains a substantial public health concern in malaria-endemic areas. Accumulation of maternal immune cells in the placenta and increased levels of inflammatory cytokines caused by sequestration of Plasmodium falciparum-infected erythrocytes (IE) in the placental intervillous blood spaces have been associated to poor neonatal outcomes, including low birth weight due to fetal growth restriction. However, little is known about the molecular changes occurring in the placenta in past-stages of P. falciparum infection when the hemozoin pigment is present in the absence of parasites. We conducted an integrated proteome, phosphoproteome and glycoproteome analysis in P. falciparum infected and non-infected placentas aiming to find molecular changes occurring in past-stage infection. A total of 2946 proteins, 1733 glycosites and 4100 phosphosites were identified and quantified in this study, disclosing overrepresented processes related to oxidative stress, protein folding and regulation of apoptosis, as well as AKT and ERK signaling pathways activation, which together with clinical data and literature-based information were further correlated to an increased apoptosis in infected placentas. This study showed apoptosis-related mechanisms associated with past-stage of malaria infection that can be further explored as therapeutic target against adverse pregnancy outcomes in placental malaria.
2018-09-25 | PXD008079 | Pride
Project description:Cerebral malaria is the most deadly manifestation of infection with Plasmodium falciparum. The pathology of cerebral malaria is characterised by the accumulation of infected erythrocytes in the microvasculature of the brain, due to parasite adhesins on the surface of infected erythrocytes binding to human receptors on microvascular endothelial cells. The parasite and host molecules involved in this interaction are unknown. We used the Human Brain Endothelial Cell line HBEC-5i to identify the malaria parasite ligands responsible for binding to human brain endothelial cells. Three P. falciparum strains (HB3, 3D7 and IT/FCR3) were selected for binding to HBEC5i and the whole transcriptome of selected and unselected parasites was analysed using a variant surface antigen-supplemented microarray chip. After selection, the only highly upregulated genes were a subset of group A-like var genes (HB3var3, 3D7_PFD0020c, ITvar7 and ITvar19), that showed 11 to >100-fold higher transcription levels in selected parasites. These genes are highly diverse in sequence, but do however show strong similarities in PfEMP1 architecture. Antibodies raised to the HB3var3 variant recognized the surface of infected erythrocytes and abolished the binding of infected erythrocytes to brain endothelial cells. The subset of Group A PfEMP1 variants identified here provides a new target for interventions to treat or prevent cerebral malaria.
2011-11-01 | GSE32211 | GEO
Project description:The most severe form of malaria is caused by Plasmodium falciparum. These parasites invade human erythrocytes and an essential step in this process involves the ligand PfRh5, which forms a complex with CyRPA and PfRipr (RCR complex) and binds basigin on the host cell. We identified a heteromeric disulphide-linked complex consisting of PfPTRAMP and PfCSS and have shown it binds RCR to form a pentameric complex PCRCR. Using P. falciparum lines with conditional knockouts and invasion inhibitory nanobodies to both PfPTRAMP and PfCSS we utilised lattice light-sheet microscopy and show they are essential for merozoite invasion. The PCRCR complex functions to anchor the contact between merozoite and erythrocyte membranes brought together by strong parasite deformations. We solved the structure of nanobody/PfCSS complexes to identify an inhibitory epitope. Our results define the function of the PCRCR complex and identify invasion neutralising epitopes providing a roadmap for structure-guided development of these proteins for a blood stage malaria vaccine.
2022-12-14 | PXD036746 | Pride