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Communications Biology Aug 2023The malaria parasite uses actin-based mechanisms throughout its lifecycle to control a range of biological processes including intracellular trafficking, gene...
The malaria parasite uses actin-based mechanisms throughout its lifecycle to control a range of biological processes including intracellular trafficking, gene regulation, parasite motility and invasion. In this work we assign functions to the Plasmodium falciparum formins 1 and 2 (FRM1 and FRM2) proteins in asexual and sexual blood stage development. We show that FRM1 is essential for merozoite invasion and FRM2 is required for efficient cell division. We also observed divergent functions for FRM1 and FRM2 in gametocyte development. Conditional deletion of FRM1 leads to a delay in gametocyte stage progression. We show that FRM2 controls the actin and microtubule cytoskeletons in developing gametocytes, with premature removal of the protein resulting in a loss of transmissible stage V gametocytes. Lastly, we show that targeting formin proteins with the small molecule inhibitor of formin homology domain 2 (SMIFH2) leads to a multistage block in asexual and sexual stage parasite development.
Topics: Actins; Formins; Plasmodium falciparum; Cell Division; Cytoskeleton
PubMed: 37596377
DOI: 10.1038/s42003-023-05233-y -
Annals of African Medicine 2024Malaria is a disease affecting millions of people, especially in Africa, Asia, and South America, and has become a substantial economic burden. Because malaria is... (Review)
Review
Malaria is a disease affecting millions of people, especially in Africa, Asia, and South America, and has become a substantial economic burden. Because malaria is contracted through the bite of a mosquito vector, it is very challenging to prevent. Bed nets and insect repellents are used in some homes; others do not have or use them even when available. Thus, treatment measures are crucial to controlling this disease. Artemisinin-based combination therapy (ACT) is currently the first-line treatment for malaria. ACT has been used for decades, but recently, there has been evidence of potential resistance. This threat of resistance has led to the search for possible alternatives to ACT. In sub-Saharan Africa, Azadirachta indica, or simply neem, is a plant used to treat a variety of ailments, including malaria. Neem is effective against one of the more deadly malaria parasites Plasmodium falciparum. Reports show that neem inhibits microgametogenesis of P. falciparum and interferes with the parasite's ookinete development. Although there is substantial in vitro research on the biological activity of A. indica (neem), there is limited in vivo research. Herein, we discuss the in vivo effects of neem on malaria parasites. With A. indica, the future of malaria treatment is promising, especially for high-risk patients, but further research and clinical trials are required to confirm its biological activity.
Topics: Animals; Humans; Plant Extracts; Malaria; Plasmodium falciparum; Africa South of the Sahara; Azadirachta; Antimalarials; Malaria, Falciparum
PubMed: 38358164
DOI: 10.4103/aam.aam_35_23 -
Biotechnology Advances Sep 2023Like any other microorganism, pathogenic protozoan parasites rely heavily on glycoconjugates and glycan binding proteins to protect themselves from the environment and... (Review)
Review
Like any other microorganism, pathogenic protozoan parasites rely heavily on glycoconjugates and glycan binding proteins to protect themselves from the environment and to interact with their diverse hosts. A thorough comprehension of how glycobiology contributes to the survival and virulence of these organisms may reveal unknown aspects of their biology and may open much needed avenues for the design of new strategies against them. In the case of Plasmodium falciparum, which causes the vast majority of malaria cases and deaths, the restricted variety and the simplicity of its glycans seemed to confer limited significance to the role played by glycoconjugates in the parasite. Nonetheless, the last 10 to 15 years of research are revealing a clearer and more defined picture. Thus, the use of new experimental techniques and the results obtained provide new avenues for understanding the biology of the parasite, as well as opportunities for the development of much required new tools against malaria.
Topics: Humans; Plasmodium falciparum; Glycomics; Malaria; Glycoconjugates
PubMed: 37216996
DOI: 10.1016/j.biotechadv.2023.108178 -
Nature Microbiology Nov 2023Malaria-associated pathogenesis such as parasite invasion, egress, host cell remodelling and antigenic variation requires concerted action by many proteins, but the...
Malaria-associated pathogenesis such as parasite invasion, egress, host cell remodelling and antigenic variation requires concerted action by many proteins, but the molecular regulation is poorly understood. Here we have characterized an essential Plasmodium-specific Apicomplexan AP2 transcription factor in Plasmodium falciparum (PfAP2-P; pathogenesis) during the blood-stage development with two peaks of expression. An inducible knockout of gene function showed that PfAP2-P is essential for trophozoite development, and critical for var gene regulation, merozoite development and parasite egress. Chromatin immunoprecipitation sequencing data collected at timepoints matching the two peaks of pfap2-p expression demonstrate PfAP2-P binding to promoters of genes controlling trophozoite development, host cell remodelling, antigenic variation and pathogenicity. Single-cell RNA sequencing and fluorescence-activated cell sorting revealed de-repression of most var genes in Δpfap2-p parasites. Δpfap2-p parasites also overexpress early gametocyte marker genes, indicating a regulatory role in sexual stage conversion. We conclude that PfAP2-P is an essential upstream transcriptional regulator at two distinct stages of the intra-erythrocytic development cycle.
Topics: Animals; Parasites; Malaria; Gene Expression Regulation; Plasmodium falciparum; Plasmodium
PubMed: 37884813
DOI: 10.1038/s41564-023-01497-6 -
MSphere Aug 2023Nonsense-mediated decay (NMD) is a conserved mRNA quality control process that eliminates transcripts bearing a premature termination codon. In addition to its role in...
Nonsense-mediated decay (NMD) is a conserved mRNA quality control process that eliminates transcripts bearing a premature termination codon. In addition to its role in removing erroneous transcripts, NMD is involved in post-transcriptional regulation of gene expression via programmed intron retention in metazoans. The apicomplexan parasite shows relatively high levels of intron retention, but it is unclear whether these variant transcripts are functional targets of NMD. In this study, we use CRISPR-Cas9 to disrupt and epitope-tag the orthologs of two core NMD components: UPF1 (PF3D7_1005500) and UPF2 (PF3D7_0925800). We localize both UPF1 and UPF2 to puncta within the parasite cytoplasm and show that these proteins interact with each other and other mRNA-binding proteins. Using RNA-seq, we find that although these core NMD orthologs are expressed and interact in , they are not required for degradation of nonsense transcripts. Furthermore, our work suggests that the majority of intron retention in has no functional role and that NMD is not required for parasite growth . IMPORTANCE In many organisms, the process of destroying nonsense transcripts is dependent on a small set of highly conserved proteins. We show that in the malaria parasite, these proteins do not impact the abundance of nonsense transcripts. Furthermore, we demonstrate efficient CRISPR-Cas9 editing of the malaria parasite using commercial Cas9 nuclease and synthetic guide RNA, streamlining genomic modifications in this genetically intractable organism.
Topics: Humans; Plasmodium falciparum; Nonsense Mediated mRNA Decay; Gene Expression Regulation; RNA, Messenger; Malaria
PubMed: 37366629
DOI: 10.1128/msphere.00233-23 -
Infection, Genetics and Evolution :... Aug 2023Malaria still poses a major burden on human health around the world, especially in endemic areas. Plasmodium resistance to several antimalarial drugs has been one of the... (Review)
Review
Malaria still poses a major burden on human health around the world, especially in endemic areas. Plasmodium resistance to several antimalarial drugs has been one of the major hindrances in control of malaria. Thus, the World Health Organization recommended artemisinin-based combination therapy (ACT) as a front-line treatment for malaria. The emergence of parasites resistant to artemisinin, along with resistant to ACT partner drugs, has led to ACT treatment failure. The artemisinin resistance is mostly related to the mutations in the propeller domain of the kelch13 (k13) gene that encodes protein Kelch13 (K13). The K13 protein has an important role in parasite reaction to oxidative stress. The most widely spread mutation in K13, with the highest degree of resistance, is a C580Y mutation. Other mutations, which are already identified as markers of artemisinin resistance, are R539T, I543T, and Y493H. The objective of this review is to provide current molecular insights into artemisinin resistance in Plasmodium falciparum. The trending use of artemisinin beyond its antimalarial effect is described. Immediate challenges and future research directions are discussed. Better understanding of the molecular mechanisms underlying artemisinin resistance will accelerate implementation of scientific findings to solve problems with malarial infection.
Topics: Humans; Plasmodium falciparum; Artemisinins; Malaria, Falciparum; Antimalarials; Mutation; Protozoan Proteins; Drug Resistance
PubMed: 37269964
DOI: 10.1016/j.meegid.2023.105460 -
Science Advances Nov 2023Drug-resistant parasites have swept across Southeast Asia and now threaten Africa. By implementing a genetic cross using humanized mice, we report the identification...
Drug-resistant parasites have swept across Southeast Asia and now threaten Africa. By implementing a genetic cross using humanized mice, we report the identification of key determinants of resistance to artemisinin (ART) and piperaquine (PPQ) in the dominant Asian KEL1/PLA1 lineage. We mapped as the central mediator of ART resistance in vitro and identified secondary markers. Applying bulk segregant analysis, quantitative trait loci mapping using 34 recombinant haplotypes, and gene editing, our data reveal an epistatic interaction between mutant PfCRT and multicopy plasmepsins 2/3 in mediating high-grade PPQ resistance. Susceptibility and parasite fitness assays implicate PPQ as a driver of selection for KEL1/PLA1 parasites. Mutant PfCRT enhanced susceptibility to lumefantrine, the first-line partner drug in Africa, highlighting a potential benefit of opposing selective pressures with this drug and PPQ. We also identified that the ABCI3 transporter can operate in concert with PfCRT and plasmepsins 2/3 in mediating multigenic resistance to antimalarial agents.
Topics: Animals; Mice; Plasmodium falciparum; Parasites; Malaria, Falciparum; Drug Resistance; Drug Resistance, Multiple; Genomics
PubMed: 37939186
DOI: 10.1126/sciadv.adi2364 -
Nature Microbiology Aug 2023Antigenic variation as a strategy to evade the host adaptive immune response has evolved in divergent pathogens. Antigenic variation involves restricted, and often... (Review)
Review
Antigenic variation as a strategy to evade the host adaptive immune response has evolved in divergent pathogens. Antigenic variation involves restricted, and often mutually exclusive, expression of dominant antigens and a periodic switch in antigen expression during infection. In eukaryotes, nuclear compartmentalization, including three-dimensional folding of the genome and physical separation of proteins in compartments or condensates, regulates mutually exclusive gene expression and chromosomal translocations. In this Review, we discuss the impact of nuclear organization on antigenic variation in the protozoan pathogens Trypanosoma brucei and Plasmodium falciparum. In particular, we highlight the relevance of nuclear organization in both mutually exclusive antigen expression and genome stability, which underlie antigenic variation.
Topics: Animals; Parasites; Antigenic Variation; Genome; Plasmodium falciparum; Cell Nucleus; Antigens
PubMed: 37524976
DOI: 10.1038/s41564-023-01424-9 -
Nature Communications Aug 2023Plasmodium falciparum (Pf) parasite development in liver represents the initial step of the life-cycle in the human host after a Pf-infected mosquito bite. While an...
Plasmodium falciparum (Pf) parasite development in liver represents the initial step of the life-cycle in the human host after a Pf-infected mosquito bite. While an attractive stage for life-cycle interruption, understanding of parasite-hepatocyte interaction is inadequate due to limitations of existing in vitro models. We explore the suitability of hepatocyte organoids (HepOrgs) for Pf-development and show that these cells permitted parasite invasion, differentiation and maturation of different Pf strains. Single-cell messenger RNA sequencing (scRNAseq) of Pf-infected HepOrg cells has identified 80 Pf-transcripts upregulated on day 5 post-infection. Transcriptional profile changes are found involving distinct metabolic pathways in hepatocytes with Scavenger Receptor B1 (SR-B1) transcripts highly upregulated. A novel functional involvement in schizont maturation is confirmed in fresh primary hepatocytes. Thus, HepOrgs provide a strong foundation for a versatile in vitro model for Pf liver-stages accommodating basic biological studies and accelerated clinical development of novel tools for malaria control.
Topics: Humans; Plasmodium falciparum; Liver; Hepatocytes; Malaria; Organoids; Malaria, Falciparum
PubMed: 37532704
DOI: 10.1038/s41467-023-40298-7 -
Nature Communications Dec 2023The proteasome of the malaria parasite Plasmodium falciparum (Pf20S) is an advantageous drug target because its inhibition kills P. falciparum in multiple stages of its...
The proteasome of the malaria parasite Plasmodium falciparum (Pf20S) is an advantageous drug target because its inhibition kills P. falciparum in multiple stages of its life cycle and synergizes with artemisinins. We recently developed a macrocyclic peptide, TDI-8304, that is highly selective for Pf20S over human proteasomes and is potent in vitro and in vivo against P. falciparum. A mutation in the Pf20S β6 subunit, A117D, confers resistance to TDI-8304, yet enhances both enzyme inhibition and anti-parasite activity of a tripeptide vinyl sulfone β2 inhibitor, WLW-vs. Here we present the high-resolution cryo-EM structures of Pf20S with TDI-8304, of human constitutive proteasome with TDI-8304, and of Pf20Sβ6 with WLW-vs that give insights into the species selectivity of TDI-8304, resistance to it, and the collateral sensitivity associated with resistance, including that TDI-8304 binds β2 and β5 in wild type Pf20S as well as WLW-vs binds β2 and β5 in Pf20Sβ6. We further show that TDI-8304 kills P. falciparum as quickly as chloroquine and artemisinin and is active against P. cynomolgi at the liver stage. This increases interest in using these structures to facilitate the development of Pf20S inhibitors that target multiple proteasome subunits and limit the emergence of resistance.
Topics: Humans; Plasmodium falciparum; Proteasome Inhibitors; Proteasome Endopeptidase Complex; Drug Collateral Sensitivity; Malaria, Falciparum; Antimalarials; Drug Resistance; Protozoan Proteins
PubMed: 38097652
DOI: 10.1038/s41467-023-44077-2