-
Science (New York, N.Y.) Aug 2019Malaria parasites adopt a remarkable variety of morphological life stages as they transition through multiple mammalian host and mosquito vector environments. We...
Malaria parasites adopt a remarkable variety of morphological life stages as they transition through multiple mammalian host and mosquito vector environments. We profiled the single-cell transcriptomes of thousands of individual parasites, deriving the first high-resolution transcriptional atlas of the entire life cycle. We then used our atlas to precisely define developmental stages of single cells from three different human malaria parasite species, including parasites isolated directly from infected individuals. The Malaria Cell Atlas provides both a comprehensive view of gene usage in a eukaryotic parasite and an open-access reference dataset for the study of malaria parasites.
Topics: Animals; Anopheles; Atlases as Topic; Genes, Protozoan; HeLa Cells; Humans; Life Cycle Stages; Malaria; Plasmodium berghei; Single-Cell Analysis; Transcriptome
PubMed: 31439762
DOI: 10.1126/science.aaw2619 -
Open Biology Aug 2022Protein phosphatase 1 (PP1) is a key enzyme for development. However, the detailed mechanisms underlying its regulation remain to be deciphered. Here, we report the...
Protein phosphatase 1 (PP1) is a key enzyme for development. However, the detailed mechanisms underlying its regulation remain to be deciphered. Here, we report the functional characterization of the leucine-rich repeat protein 1 (PbLRR1), an orthologue of SDS22, one of the most ancient and conserved PP1 interactors. Our study shows that PbLRR1 is expressed during intra-erythrocytic development of the parasite, and up to the zygote stage in mosquitoes. PbLRR1 can be found in complex with PbPP1 in both asexual and sexual stages and inhibits its phosphatase activity. Genetic analysis demonstrates that PbLRR1 depletion adversely affects the development of oocysts. PbLRR1 interactome analysis associated with phospho-proteomics studies identifies several novel putative PbLRR1/PbPP1 partners. Some of these partners have previously been characterized as essential for the parasite sexual development. Interestingly, and for the first time, Inhibitor 3 (I3), a well-known and direct interactant of PP1, was found to be drastically hypophosphorylated in PbLRR1-depleted parasites. These data, along with the detection of I3 with PP1 in the LRR1 interactome, strongly suggest that the phosphorylation status of PbI3 is under the control of the PP1-LRR1 complex and could contribute (in)directly to oocyst development. This study provides new insights into previously unrecognized PbPP1 fine regulation of oocyst development through its interaction with PbLRR1.
Topics: Animals; Leucine-Rich Repeat Proteins; Oocysts; Phosphorylation; Plasmodium berghei; Protein Phosphatase 1
PubMed: 35920043
DOI: 10.1098/rsob.220015 -
MicrobiologyOpen Jul 2020Male and female Plasmodium gametocytes ingested by the Anopheles mosquitoes during a blood meal egress from the red blood cells by rupturing the two surrounding...
Male and female Plasmodium gametocytes ingested by the Anopheles mosquitoes during a blood meal egress from the red blood cells by rupturing the two surrounding membranes, the parasitophorous vacuole and the red blood cell membranes. Proteins of the so-called osmiophilic bodies, (OBs), secretory organelles resident in the cytoplasm, are important players in this process. Once gametes emerge, the female is ready to be fertilized while the male develops into motile flagellar gametes. Here, we describe the function(s) of PBANKA_1115200, which we named Gamete Egress Protein (GEP), a protein specific to malaria parasites. GEP is restricted to gametocytes, expressed in gametocytes of both genders and partly localizes to the OBs. A mutant lacking the protein shows aberrant rupture of the two surrounding membranes, while OBs discharge is delayed but not aborted. Moreover, we identified a second function of GEP during exflagellation since the axonemes of the male flagellar gametes were not motile. Genetic crossing experiments reveal that both genders are unable to establish infections in mosquitoes and thus the lack of GEP leads to a complete block in Plasmodium transmission from mice to mosquitoes. The combination of our results reveals essential and pleiotropic functions of GEP in Plasmodium gametogenesis.
Topics: Animals; Anopheles; Erythrocytes; Female; Gametogenesis; Gene Knockout Techniques; Germ Cells; Malaria; Male; Mice; Plasmodium berghei; Protozoan Proteins
PubMed: 32352241
DOI: 10.1002/mbo3.1038 -
Parasite Immunology Nov 2020Merozoite surface protein 8 (MSP-8) of Plasmodium parasites plays an important role in erythrocyte invasion and is a potential malaria vaccine candidate.
AIMS
Merozoite surface protein 8 (MSP-8) of Plasmodium parasites plays an important role in erythrocyte invasion and is a potential malaria vaccine candidate.
METHODS AND RESULTS
In this study, virus-like particles (VLPs) expressing MSP-8 of Plasmodium berghei on the surface of influenza virus matrix protein 1 (M1) core protein were generated for vaccine efficacy assessment. Mice were intramuscularly (IM) immunized with MSP-8 VLPs twice and challenge-infected with P. berghei. We found that VLP vaccination elicited higher levels of P. berghei-specific IgG antibody response in the sera, along with blood CD4 and CD8 T-cell response enhancement compared to the naïve control mice. CD4 and CD8 effector memory T-cell and memory B-cell responses in the spleen were found to be higher in VLP-immunized mice compared to control mice. VLP vaccination significantly reduced inflammatory cytokine (IFN-γ) response in the spleen and parasitemia levels in blood compared to naïve control mice.
CONCLUSIONS
These results indicate that MSP-8 containing virus-like particles could be a vaccine candidate for blood-stage vaccine design.
Topics: Animals; Antigens, Protozoan; Female; Immunization; Malaria; Malaria Vaccines; Mice; Mice, Inbred BALB C; Parasitemia; Plasmodium berghei; Protozoan Proteins
PubMed: 32738150
DOI: 10.1111/pim.12781 -
Eukaryotic Cell Nov 2008
Review
Topics: Animals; Antibodies, Protozoan; Antigens, Protozoan; Disease Models, Animal; Humans; Malaria; Malaria Vaccines; Mice; Plasmodium berghei
PubMed: 18806208
DOI: 10.1128/EC.00242-08 -
Molecular and Biochemical Parasitology Mar 2010Malaria crystalloids are unique organelles of unknown function that are present only in the mosquito-specific ookinete and early oocyst stages of the parasite. Recently,...
Malaria crystalloids are unique organelles of unknown function that are present only in the mosquito-specific ookinete and early oocyst stages of the parasite. Recently, crystalloid formation in Plasmodium berghei was linked to the parasite protein PbSR, a member of the Plasmodium LCCL protein family composed of six modular multidomain proteins involved in sporozoite development and infectivity. Here, we show by fluorescent protein tagging that two other LCCL protein family members are targeted to the crystalloids in a similar way to PbSR. These results extend the similarities between the LCCL proteins, and provide strong supporting evidence for the hypothesis that members of this protein family work in concert and are involved in a similar molecular process.
Topics: Organelles; Plasmodium berghei; Protein Transport; Protozoan Proteins
PubMed: 19932717
DOI: 10.1016/j.molbiopara.2009.11.008 -
Phosphoglycolate phosphatase is a metabolic proofreading enzyme essential for cellular function in .The Journal of Biological Chemistry Mar 2019(Pf) 4-nitrophenylphosphatase has been shown previously to be involved in vitamin B1 metabolism. Here, conducting a BLASTp search, we found that...
(Pf) 4-nitrophenylphosphatase has been shown previously to be involved in vitamin B1 metabolism. Here, conducting a BLASTp search, we found that 4-nitrophenylphosphatase from Pf has significant homology with phosphoglycolate phosphatase (PGP) from mouse, human, and yeast, prompting us to reinvestigate the biochemical properties of the enzyme. Because the recombinant PfPGP enzyme is insoluble, we performed an extended substrate screen and extensive biochemical characterization of the recombinantly expressed and purified homolog from (Pb), leading to the identification of 2-phosphoglycolate and 2-phospho-L-lactate as the relevant physiological substrates of PbPGP. 2-Phosphoglycolate is generated during repair of damaged DNA ends, 2-phospho-L-lactate is a product of pyruvate kinase side reaction, and both potently inhibit two key glycolytic enzymes, triosephosphate isomerase and phosphofructokinase. Hence, PGP-mediated clearance of these toxic metabolites is vital for cell survival and functioning. Our results differ significantly from those in a previous study, wherein the PfPGP enzyme has been inferred to act on 2-phospho-D-lactate and not on the L isomer. Apart from resolving the substrate specificity conflict through direct enzyme assays, we conducted PGP gene knockout studies in , confirming that this conserved metabolic proofreading enzyme is essential in In summary, our findings establish PbPGP as an essential enzyme for normal physiological function in and suggest that drugs that specifically inhibit PGP may hold promise for use in anti-malarial therapies.
Topics: Animals; Gene Knockout Techniques; Glycolates; Glycolysis; Humans; Lactates; Malaria; Mice; Molecular Sequence Data; Phosphoric Monoester Hydrolases; Plasmodium berghei; Protozoan Proteins; Sequence Alignment; Substrate Specificity
PubMed: 30700551
DOI: 10.1074/jbc.AC118.007143 -
Methods in Molecular Biology (Clifton,... 2015Direct detection and quantification of liver-stage Plasmodium parasites became possible with the development of quantitative real-time PCR (qPCR). Here we describe the...
Direct detection and quantification of liver-stage Plasmodium parasites became possible with the development of quantitative real-time PCR (qPCR). Here we describe the measurement of parasite burden in the livers of mice infected with the rodent malaria species, Plasmodium berghei and Plasmodium yoelii. This method is based on detection of expression of parasite ribosomal 18S RNA and can serve as an endpoint to accurately evaluate the efficacy of vaccines targeting the preerythrocytic stages of malaria. This approach is fast and highly reproducible and allows quantification of liver-stage parasite burden in different mouse strains and different Plasmodium species after infection with a range of sporozoite challenge doses.
Topics: Animals; Humans; Liver; Malaria; Mice; Plasmodium berghei; Plasmodium yoelii; RNA, Ribosomal, 18S; Real-Time Polymerase Chain Reaction
PubMed: 26450381
DOI: 10.1007/978-1-4939-2815-6_7 -
Acta Tropica Oct 2021Genetic changes conferring drug resistance are generally believed to impose fitness costs to pathogens in the absence of the drug. However, the fitness of resistant...
Genetic changes conferring drug resistance are generally believed to impose fitness costs to pathogens in the absence of the drug. However, the fitness of resistant parasites against sulfadoxine/pyrimethamine has been inconclusive in Plasmodium falciparum. This is because resistance is conferred by the complex combination of mutations in dihydropteroate synthase (dhps) and dihydrofolate reductase (dhfr), which makes it difficult to separately assess the extent and magnitude of the costs imposed by mutations in dhps and dhfr. To assess the fitness costs imposed by sulfadoxine resistance alone, we generated a transgenic rodent malaria parasite, P. berghei clone harboring an A394G mutation in dhps (PbDHPS-A394G), corresponding to the causative mutation for sulfadoxine resistance in P. falciparum (PfDHPS-A437G). A four-day suppressive test confirmed that the PbDHPS-A394G clone was resistant to sulfadoxine. PbDHPS-A394G and wild-type clones showed similar growth rates and gametocyte production. This observation was confirmed in competitive experiments in which PbDHPS-A394G and wild-type clones were co-infected into mice to directly assess the survival competition between them. In the mosquitoes, there were no significant differences in oocyst production between PbDHPS-A394G and wild-type. These results indicate that the PbDHPS-A394G mutation alters the parasites to sulfadoxine resistance but may not impose fitness disadvantages during the blood stages in mice and oocyst formation in mosquitoes. These results partly explain the persistence of the PfDHPS-A437G mutant in the natural parasite populations.
Topics: Animals; Antimalarials; Dihydropteroate Synthase; Drug Combinations; Drug Resistance; Mice; Mutation; Plasmodium berghei; Pyrimethamine; Sulfadoxine; Tetrahydrofolate Dehydrogenase
PubMed: 34273314
DOI: 10.1016/j.actatropica.2021.106049 -
Nature Reviews. Microbiology Aug 2016Plasmodium parasites, the causative agents of malaria, have developed elaborate strategies that they use to survive and thrive within different intracellular... (Review)
Review
Plasmodium parasites, the causative agents of malaria, have developed elaborate strategies that they use to survive and thrive within different intracellular environments. During the blood stage of infection, the parasite is a master renovator of its erythrocyte host cell, and the changes in cell morphology and function that are induced by the parasite promote survival and contribute to the pathogenesis of severe malaria. In this Review, we discuss how Plasmodium parasites use the protein trafficking motif Plasmodium export element (PEXEL), protease-mediated polypeptide processing, a novel translocon termed the Plasmodium translocon of exported proteins (PTEX) and exomembranous structures to export hundreds of proteins to discrete subcellular locations in the host erythrocytes, which enables the parasite to gain access to vital nutrients and to evade the immune defence mechanisms of the host.
Topics: Amino Acid Motifs; Animals; Erythrocytes; Host-Pathogen Interactions; Humans; Immune Evasion; Malaria; Malaria, Falciparum; Plasmodium berghei; Plasmodium falciparum; Protein Sorting Signals; Protein Translocation Systems; Protein Transport; Protozoan Proteins; Transport Vesicles
PubMed: 27374802
DOI: 10.1038/nrmicro.2016.79