Project description:Background: Host iron deficiency is protective against severe malaria as the human malaria parasite Plasmodium falciparum depends on free iron from its host to proliferate. Due to the absence of transferrin, ferritin, ferroportin, and a functional heme oxygenase, the parasite’s essential pathways of iron acquisition, storage, export, and detoxification differ from those in humans and may thus be excellent targets for therapeutic development. However, the proteins involved in these processes in P. falciparum remain largely unknown. Experimental design: To identify iron-regulated mechanisms and putative iron transporters in the human malaria parasite Plasmodium falciparum 3D7, we carried out whole-transcriptome profiling using bulk RNA-sequencing. The parasites were cultured either using erythrocytes from a donors with high, medium (healthy) or low iron status (experiment 1); or with red blood cells from another healthy donor in the presence or absence of 0.7 µM hepcidin, a specific ferroportin inhibitor and iron-regulatory hormone (experiment 2). This concentration of hepcidin was reported to reduce binding of ferrous iron to ferroportin by 50% in vitro (39). Samples from three biological replicates each were harvested at the ring and trophozoite stage (6 – 9 and 26 – 29 hours post invasion, hpi) during the second intra-erythrocytic developmental cycle under the conditions specified.
Project description:Severe presentations of malaria emerge as parasites from Plasmodium spp. proliferate and lyse red blood cells (RBC), producing extracellular hemoglobin (HB). The heme prosthetic groups are released upon HB oxidation generating circulating labile heme. Here we asked whether scavenging of extracellular HB and/or labile heme, by haptoglobin (HP) and/or hemopexin (HPX), respectively, is protective against severe presentations of malaria. We found that circulating labile heme is an independent risk factor for cerebral and non-cerebral severe presentations of P. falciparum malaria. Labile heme was negatively correlated with HP and HPX, which were however, not risk factors for severe P. falciparum malaria. Genetic HP and/or HPX deletion in mice led to accumulation of labile heme in plasma and kidneys in response to Plasmodium (chabaudi chabaudi) infection. This was associated with increased mortality and acute kidney injury (AKI) in ageing but not adult mice, corroborated in P. falciparum malaria by a an inverse correlation between HPX and heme with serological markers of AKI. In conclusion, HP and HPX exert an age-dependent protective effect against malaria that counters the pathogenesis of AKI in mice and presumably in humans.
Project description:Recent studies of the Puf family of RNA-binding proteins revealed that besides their traditional roles in translational regulation of mRNAs, some Puf proteins are also involved in ribosome biogenesis by binding rRNA. In this study, we report the role of a Puf-like protein in Plasmodium falciparum (name as PfPuf3) and its ortholog PyPuf3 in Plasmodium yoelii in ribosome biogenesis. Secondary structure prediction suggested that the RNA-binding domain of Puf3 consists of 11 pumilio repeats, similar to human Puf-A/yeast Puf6, which involved in ribosome biogenesis. Neither pfpuf3 nor pypuf3 could be genetically disrupted, suggesting they may be essential for the intraerythrocytic developmental cycle (IDC). A time-course study of PfPuf3 protein indicated that PfPuf3 was expressed during the entire IDC, with peak expression in early trophozoites. Cellular fractionation of PfPuf3 revealed that it is preferentially partitioned to the nuclear than the cytoplasmic fractions, which is consistent with a nuclear localization of PfPuf3::GFP and PyPuf3::GFP as seen by immunofluorescence. Further, we found PfPuf3 co-localized with a well-known nucleolus maker, PfNop1, demonstrating that PfPuf3 is a nucleolar protein. This localization is in contrast to the cytoplasmic localization of PfPuf1 and PfPuf2, but matches the localization of human Puf-A and yeast Puf6. Affinity purification of an N-terminal PTP-tagged variant of PfPuf3 revealed an association with 32 proteins associated with the 60S ribosome, and an enrichment of 28S rRNA and ITS2. Taken together, these results demonstrate a nucleolar localization of PfPuf3 and suggest an essential function of PfPuf3 in ribosomal biogenesis.
Project description:Gene expression data from whole-blood collected from Kenyan children with Plasmodium falciparum malaria infection at acute hospital admission (n=15) and at convalescence (n=9). A clinical history design type is where the organisms clinical history of diagnosis, treatments, e.g. vaccinations, surgery etc. Disease State: with Plasmodium falciparum malaria infection at acute hospital admission and at convalescence clinical_history_design
Project description:Gene expression data from whole-blood collected from healthy Vietnamese subjects (n=8) or from patients admitted to hospital with acute uncomplicated (n=9) or complicated (n=20) Plasmodium falciparum malaria infection. A clinical history design type is where the organisms clinical history of diagnosis, treatments, e.g. vaccinations, surgery etc. Disease State: patient with complicated or uncomplicated Plasmodium falciparum malaria infection or Healthy control clinical_history_design
Project description:Gene expression data from whole-blood collected from Kenyan children with Plasmodium falciparum malaria infection at acute hospital admission (n=15) and at convalescence (n=9). A clinical history design type is where the organisms clinical history of diagnosis, treatments, e.g. vaccinations, surgery etc. Disease State: with Plasmodium falciparum malaria infection at acute hospital admission and at convalescence
Project description:Gene expression data from whole-blood collected from healthy Vietnamese subjects (n=8) or from patients admitted to hospital with acute uncomplicated (n=9) or complicated (n=20) Plasmodium falciparum malaria infection. A clinical history design type is where the organisms clinical history of diagnosis, treatments, e.g. vaccinations, surgery etc. Disease State: patient with complicated or uncomplicated Plasmodium falciparum malaria infection or Healthy control
Project description:These data were used to assess gene expression and dynamics between oocyst sporozoites and salivary gland sporozoites for both Plasmodium falciparum and Plasmodium yoelii.
Project description:Twenty years since publication of the Plasmodium falciparum and P. berghei genomes one-third of their protein-coding genes lack functional annotation. In the absence of sequence and structural homology, protein-protein interactions can facilitate functional prediction of such orphan genes by mapping protein complexes in their natural cellular environment. The Plasmodium NPC (nuclear pore complex) is a case in point: it remains poorly defined; its constituents lack conservation with the 30+ proteins described in the NPC of many opisthokonts, a clade of eukaryotes that includes fungi and animals, but not Plasmodium. Here we developed a labeling methodology based on TurboID fusion proteins, which allows visualization of the berghei NPC and facilitates the identification of its components. Following affinity purification and mass spectrometry we identify four known Nups (138, 205, 221, and the bait 313) and verify interaction with the putative FG Nup637; we assign five proteins lacking annotation (and therefore meaningful homology with proteins outside the genus) to the NPC, which is confirmed by GFP tagging. Based on gene deletion attempts, all new Nups Nup176, 269, 335, 390, and 434 are essential to parasite survival. They lack primary sequence homology with proteins outside the Plasmodium genus; albeit two incorporate short domains with structural homology to human Nup155 and yeast Nup157, and the condensin SMC4. The protocols developed here showcase the power of proximity-labeling for elucidating protein complex composition and annotation in Plasmodium. It opens the door to exploring the function of the Plasmodium NPC and understanding its evolutionary position.
Project description:Paper: Transcriptional Profiling of Plasmodium falciparum Parasites from Patients with Severe Malaria Identifies Distinct Low vs. High Parasitemic Clusters Milner et al Plos One July 18, 2012 Plasmodium falciparum Parasites from Patients with Severe Malaria