Project description:Nilsson Bark SK, Ahmad R, Dantzler K, Lukens AK, De Niz M, Szucs MJ, Jin X, Cotton J, Hoffmann D, Bric-Furlong E, Oomen R, Parrington M, Milner D, Neafsey DE, Carr SA, Wirth DF, Marti M. Mol Cell Proteomics 2017. Despite recent efforts towards control and elimination, malaria remains a major public health problem worldwide. Plasmodium falciparum resistance against artemisinin, used in front line combination drugs, is on the rise, and the only approved vaccine shows limited efficacy. Combinations of novel and tailored drug and vaccine interventions are required to maintain the momentum of the current malaria elimination program. Current evidence suggests that strain-transcendent protection against malaria infection can be achieved using whole organism vaccination or with a polyvalent vaccine covering multiple antigens or epitopes. These approaches have been successfully applied to the human-infective sporozoite stage. Both systemic and tissue-specific pathology during infection with the human malaria parasite P. falciparum is caused by asexual blood stages. Tissue tropism and vascular sequestration are the result of specific binding interactions between antigens on the parasite-infected red blood cell (pRBC) surface and endothelial receptors. The major surface antigen and parasite ligand binding to endothelial receptors, PfEMP1 is encoded by about 60 variants per genome and shows high sequence diversity across strains. Apart from PfEMP1 and three additional variant surface antigen families RIFIN, STEVOR and SURFIN, systematic analysis of the infected red blood cell surface is lacking. Here we present the most comprehensive proteomic investigation of the parasitized red blood cell surface so far. Apart from the known variant surface antigens, we identified a set of putative single copy surface antigens with low sequence diversity, several of which are validated in a series of complementary experiments. Further functional and immunological investigation is underway to test these novel P. falciparum blood stage proteins as possible vaccine candidates.
Project description:Determination of gene expression level changes of whole genome during Plasmodium falciparum development in early liver stage (at 24h and 48h), compared to mixed blood stage and sporozoite stage. A set of Genes selected from this expression analysis are further verified by qPCR and a sub-set were tested for their vaccine efficacy.
Project description:Determination of gene expression level changes of whole genome during Plasmodium falciparum development in early liver stage (at 24h and 48h), compared to mixed blood stage and sporozoite stage. A set of Genes selected from this expression analysis are further verified by qPCR and a sub-set were tested for their vaccine efficacy. 6 genomic tiling arrays: 3 time points in early liver infection (spz, hr24, hr48), and 3 blood stage isolates
Project description:The purpose of this research is to identify and evaluate the global gene expression of the rodent malaria parasites Plasmodium yoelii, Plasmodium berghei and Plasmodium chabaudi blood-stage parasites and specifically compare the blood stage gene expression profiles of samples derived from previous studies on Plasmodium falciparum, Plasmodium vivax and Plasmodium knowlesi
Project description:Background: Plasmodium falciparum causes the majority of malaria mortality worldwide, and the disease occurs during the asexual red blood cell (RBC) stage of infection. In the absence of an effective and available vaccine, and with increasing drug resistance, asexual RBC stage parasites are an important research focus. In recent years, mass spectrometry-based proteomics using Data Dependent Acquisition (DDA) has been extensively used to understand the biochemical processes within the parasite. However, DDA is problematic for the detection of low abundance proteins, protein coverage, and has poor run-to-run reproducibility. Results: Here, we present a comprehensive P. falciparum-infected RBC (iRBC) spectral library to measure the abundance of 44,449 peptides from 3,113 P. falciparum and 1,617 RBC proteins using a Data Independent Acquisition (DIA) approach. The spectral library includes proteins expressed in the three morphologically distinct RBC stages (ring, trophozoite, schizont), the RBC compartment of trophozoite-iRBCs, and the cytosolic fractions from uninfected RBCs (uRBC). This spectral library contains 87% of P. falciparum proteins with previously blood-stage protein-level evidence as well as 692 previously unidentified proteins. The P. falciparum spectral library was successfully applied to generate semi-quantitative proteomics datasets that characterise the three distinct asexual parasite stages in RBCs, and compare artemisinin resistant (Cam3.IIR539T) and sensitive (Cam3.IIrev) parasites. Conclusion: A reproducible, high-coverage proteomics spectral library and analysis method has been generated for investigating sets of proteins expressed in the iRBC stage of P. falciparum malaria. This will provide a foundation for an improved understanding of parasite biology, pathogenesis, drug mechanisms and vaccine candidate discovery for malaria.
Project description:Background: Plasmodium falciparum causes the majority of malaria mortality worldwide, and the disease occurs during the asexual red blood cell (RBC) stage of infection. In the absence of an effective and available vaccine, and with increasing drug resistance, asexual RBC stage parasites are an important research focus. In recent years, mass spectrometry-based proteomics using Data Dependent Acquisition (DDA) has been extensively used to understand the biochemical processes within the parasite. However, DDA is problematic for the detection of low abundance proteins, protein coverage, and has poor run-to-run reproducibility. Results: Here, we present a comprehensive P. falciparum-infected RBC (iRBC) spectral library to measure the abundance of 44,449 peptides from 3,113 P. falciparum and 1,617 RBC proteins using a Data Independent Acquisition (DIA) approach. The spectral library includes proteins expressed in the three morphologically distinct RBC stages (ring, trophozoite, schizont), the RBC compartment of trophozoite-iRBCs, and the cytosolic fractions from uninfected RBCs (uRBC). This spectral library contains 87% of P. falciparum proteins with previously blood-stage protein-level evidence as well as 692 previously unidentified proteins. The P. falciparum spectral library was successfully applied to generate semi-quantitative proteomics datasets that characterise the three distinct asexual parasite stages in RBCs, and compare artemisinin resistant (Cam3.IIR539T) and sensitive (Cam3.IIrev) parasites. Conclusion: A reproducible, high-coverage proteomics spectral library and analysis method has been generated for investigating sets of proteins expressed in the iRBC stage of P. falciparum malaria. This will provide a foundation for an improved understanding of parasite biology, pathogenesis, drug mechanisms and vaccine candidate discovery for malaria.
Project description:Red blood cells (RBC) play a critical role in oxygen transport, and are the focus of important human diseases including malaria and the haemoglobinopathies. Although previous studies aimed at classifying the RBC proteome have examined whole or membrane-enriched fractions from RBC, none have used specific strategies directed at enriching proteins with exposed extracellular domains. Furthermore, there has been no systematic analysis of variation in abundance of RBC surface proteins either within or between genetically disparate human populations. These questions are of particular importance to inform not only basic RBC biology but additionally to identify novel candidate Plasmodium receptors, where selective pressures have moulded the RBC surface, exemplified by genetic absence of Duffy antigen in populations from sub-Saharan Africa. Here, we use ‘Plasma membrane profiling’ and tandem mass tag-based mass spectrometry to specifically enrich and quantify cell surface proteins from primary RBC from two sets of nine donors from the UK or Senegal. We define a ‘stringent’ and ‘sensitive’ RBC surface proteome and identify potential candidate Plasmodium receptors on the basis either of diminished protein abundance, or increased variation in West African individuals compared to people from the UK.
Project description:RTS,S is the sole candidate vaccine shown to provide protection against infection to malaria-naive adults challenged with mosquito-borne homologous falciparum malaria and protection against infection and clinical and severe disease to volunteers in malaria-endemic Africa who were exposed to diverse Plasmodium falciparum strains. In this experiment we profiled gene expression in PBMCs after vaccination with the RTS,S candidate malaria vaccine in a controlled human malaria infection study. Subjects were vaccinated with three doses of the RTS,S candidate malaria vaccine. Blood samples for PBMC isolation and subsequent gene expression analysis were taken on day 0 (0m), day of the third vaccination (8w), 1 day post third vaccination (8w1d), 3 days post third vaccination (8w3d), the day of the infection (10w), 1 day post infection (10w1d), and 5 days post infection (10w5d). After infection the subjects were closely monitored for parasitemia. The response to the controlled infection was recorded as follows: no parasitemia (P, protected), parasitemia in the same time frame as the control group (NP, not protected), parasitemia later than the control group (DL, delayed). In addition to the experimental factors, a confounding factor was identified in the data analysis related to the use of a specific kit batch (Kit A or B).
Project description:Transcription time course of Plasmodium falciparum parasite asexual blood stage progression in the presence of antimalarial drug CID5750730 (Compound C)