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ACS Nano Sep 2018Nanoscale organization is crucial to stimulating an immune response. Using self-assembling proteins as multimerization platforms provides a safe and immunogenic system...
Nanoscale organization is crucial to stimulating an immune response. Using self-assembling proteins as multimerization platforms provides a safe and immunogenic system to vaccinate against otherwise weakly immunogenic antigens. Such multimerization platforms are generally based on icosahedral viruses and have led to vaccines given to millions of people. It is unclear whether synthetic protein nanoassemblies would show similar potency. Here we take the computationally designed porous dodecahedral i301 60-mer and rationally engineer this particle, giving a mutated i301 (mi3) with improved particle uniformity and stability. To simplify the conjugation of this nanoparticle, we employ a SpyCatcher fusion of mi3, such that an antigen of interest linked to the SpyTag peptide can spontaneously couple through isopeptide bond formation (Plug-and-Display). SpyCatcher-mi3 expressed solubly to high yields in Escherichia coli, giving more than 10-fold greater yield than a comparable phage-derived icosahedral nanoparticle, SpyCatcher-AP205. SpyCatcher-mi3 nanoparticles showed high stability to temperature, freeze-thaw, lyophilization, and storage over time. We demonstrate approximately 95% efficiency coupling to different transmission-blocking and blood-stage malaria antigens. Plasmodium falciparum CyRPA was conjugated to SpyCatcher-mi3 nanoparticles and elicited a high avidity antibody response, comparable to phage-derived virus-like particles despite their higher valency and RNA cargo. The simple production, precise derivatization, and exceptional ruggedness of this nanoscaffold should facilitate broad application for nanobiotechnology and vaccine development.
Topics: Nanoparticles; Nanotechnology; Particle Size; Peptides; Plasmodium falciparum; Porosity; Surface Properties; Vaccination
PubMed: 30028591
DOI: 10.1021/acsnano.8b02805 -
Genes May 2021Genomics has revolutionised the study of the biology of parasitic diseases. The first Eukaryotic parasite to have its genome sequenced was the malaria parasite . Since... (Review)
Review
Genomics has revolutionised the study of the biology of parasitic diseases. The first Eukaryotic parasite to have its genome sequenced was the malaria parasite . Since then, genomics has continued to lead the way in the study of the genome biology of parasites, both in breadth-the number of species' genomes sequenced-and in depth-massive-scale genome re-sequencing of several key species. Here, we review some of the insights into the biology, evolution and population genetics of gained from genome sequencing, and look at potential new avenues in the future genome-scale study of its biology.
Topics: Epigenome; Genome, Protozoan; Humans; Malaria; Plasmodium falciparum; Polymorphism, Genetic
PubMed: 34070769
DOI: 10.3390/genes12060843 -
Current Opinion in Microbiology Oct 2022Most eukaryotic proteins undergo post-translational modifications (PTMs) that significantly alter protein properties, regulate diverse cellular processes and increase... (Review)
Review
Most eukaryotic proteins undergo post-translational modifications (PTMs) that significantly alter protein properties, regulate diverse cellular processes and increase proteome complexity. Among these PTMs, lipidation plays a unique and key role in subcellular trafficking, signalling and membrane association of proteins through altering substrate function, and hydrophobicity via the addition and removal of lipid groups. Three prevalent classes of lipid modifications in Plasmodium parasites include prenylation, myristoylation, and palmitoylation that are important for regulating parasite-specific molecular processes. The enzymes that catalyse these lipid attachments have also been explored as potential drug targets for antimalarial development. In this review, we discuss these lipidation processes in Plasmodium spp. and the methodologies that have been used to identify these modifications in the deadliest species of malaria parasite, Plasmodium falciparum. We also discuss the development status of inhibitors that block these pathways.
Topics: Animals; Lipids; Parasites; Plasmodium; Plasmodium falciparum; Protein Processing, Post-Translational; Protozoan Proteins
PubMed: 36037636
DOI: 10.1016/j.mib.2022.102196 -
Molecular and Biochemical Parasitology Jul 2021The sexual blood stages of the human malaria parasite Plasmodium falciparum undergo a remarkable transformation from a roughly spherical shape to an elongated crescent... (Review)
Review
The sexual blood stages of the human malaria parasite Plasmodium falciparum undergo a remarkable transformation from a roughly spherical shape to an elongated crescent or "falciform" morphology from which the species gets its name. In this review, the molecular events that drive this spectacular shape change are discussed and some questions that remain regarding the mechanistic underpinnings are posed. We speculate on the role of the shape changes in promoting sequestration and release of the developing gametocyte, thereby facilitating parasite survival in the host and underpinning transmission to the mosquito vector.
Topics: Animals; Biomechanical Phenomena; Culicidae; Erythrocytes; Female; Gametogenesis; Hepatocytes; Host-Parasite Interactions; Humans; Insect Vectors; Life Cycle Stages; Malaria, Falciparum; Male; Microtubules; Plasmodium falciparum; Reproduction, Asexual
PubMed: 34062177
DOI: 10.1016/j.molbiopara.2021.111385 -
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 -
Journal of Travel Medicine Jun 2019Artemisinin-based combination therapy (ACT) is the global standard of care for uncomplicated falciparum malaria. First reports of ACT resistance came from western... (Review)
Review
BACKGROUND
Artemisinin-based combination therapy (ACT) is the global standard of care for uncomplicated falciparum malaria. First reports of ACT resistance came from western Cambodia and the Thailand-Cambodia border in 2002-2004. The subsequent emergence and expansion of Plasmodium falciparum strains resistant to the artemisinin component and ACT are now threatening the efficacy of falciparum malaria treatment.
METHODS
We performed a literature review on the history and the current degree of geographic expansion of artemisinin and ACT resistance. Resistance against artemisinins is defined as >5% of patients carrying PfKelch13 (K13) mutations, all of whom have been found to have persistent parasitaemia by microscopy on Day 3 after treatment.
RESULTS
Several studies including the multi-centre Tracking Resistance to Artemisinin Collaboration study investigated artemisinin resistance in Southeast Asia and beyond and demonstrated increasing prevalence of P. falciparum infections with slow parasite clearance rates in the Greater Mekong Subregion (GMS). K13 mutations were strongly associated with delayed P. falciparum parasite clearance, and the prevalence of the mutation PfKelch13 C580Y is increasing in the GMS. Resistance to ACT regimens is now well established in western Cambodia and in eastern Thailand, southern Laos and southern Vietnam. Moreover, the prevalence of slow P. falciparum parasite clearance has continuously increased over the past 10-15 years at the Thailand-Myanmar border, in nearly all regions of Myanmar, and at the Myanmar-China border.
CONCLUSION
Multidrug resistant malaria is a rapidly increasing problem, but fortunately still limited to Southeast Asia, in particular to the GMS. In the long-term it may threaten global progress in malaria control but is not yet of concern with regards to malaria prophylaxis, as ACTs are not used for prevention in travellers, current ACT regimens are still effective in most malaria endemic areas outside the GMS and the preferred travellers' prophylaxis atovaquone-proguanil and doxycycline remain protective. However, artemsinin resistance in the GMS is of real concern to travellers as it will affect the choice of malaria treatment including standby-emergence treatment.
Topics: Antimalarials; Artemisinins; Asia; Drug Resistance; Genotype; Humans; Malaria, Falciparum; Mutation; Plasmodium falciparum; Travel
PubMed: 30995310
DOI: 10.1093/jtm/taz030 -
Molecular and Biochemical Parasitology Aug 2016Members of the phylum Apicomplexa are responsible for many devastating diseases including malaria (Plasmodium spp.), toxoplasmosis (Toxoplasma gondii), babesiosis... (Review)
Review
Members of the phylum Apicomplexa are responsible for many devastating diseases including malaria (Plasmodium spp.), toxoplasmosis (Toxoplasma gondii), babesiosis (Babesia bovis), and cyclosporiasis (Cyclospora cayetanensis). Most Apicomplexans contain a unique and essential organelle called the apicoplast. Derived from an ancient chloroplast, the apicoplast replicates and maintains a 35 kilobase (kb) circular genome. Due to its essential nature within the parasite, drugs targeted to proteins involved in DNA replication and repair of the apicoplast should be potent and specific. This review summarizes the current knowledge surrounding the replication and repair of the Plasmodium falciparum apicoplast genome and identifies several putative proteins involved in replication and repair pathways.
Topics: Antimalarials; Apicoplasts; DNA Repair; DNA Replication; DNA-Binding Proteins; Drug Discovery; Genome, Protozoan; Genomics; Plasmodium falciparum; Protozoan Proteins
PubMed: 27338018
DOI: 10.1016/j.molbiopara.2016.06.006 -
Journal of Microbiology (Seoul, Korea) Apr 2017Malaria has been present since ancient time and remains a major global health problem in developing countries. Plasmodium falciparum belongs to the phylum Apicomplexan,... (Review)
Review
Malaria has been present since ancient time and remains a major global health problem in developing countries. Plasmodium falciparum belongs to the phylum Apicomplexan, largely contain disease-causing parasites and characterized by the presence of apicoplast. It is a very essential organelle of P. falciparum responsible for the synthesis of key molecules required for the growth of the parasite. Indispensable nature of apicoplast makes it a potential drug target. Calcium signaling is important in the establishment of malaria parasite inside the host. It has been involved in invasion and egress of merozoites during the asexual life cycle of the parasite. Calcium signaling also regulates apicoplast metabolism. Therefore, in this review, we will focus on the role of apicoplast in malaria biology and its metabolic regulation through Ca signaling.
Topics: Apicoplasts; Calcium; Calcium Signaling; Gene Expression Regulation; Plasmodium falciparum
PubMed: 28251546
DOI: 10.1007/s12275-017-6525-1 -
Malaria Journal Feb 2016Facing chloroquine drug resistance, Angola promptly adopted artemisinin-based combination therapy as the first-line to treat malaria. Currently, the country aims to... (Review)
Review
Facing chloroquine drug resistance, Angola promptly adopted artemisinin-based combination therapy as the first-line to treat malaria. Currently, the country aims to consolidate malaria control, while preparing for the elimination of the disease, along with others African countries in the region. However, the remarkable capacity of Plasmodium to develop drug resistance represents an alarming threat for those achievements. Herein, the available, but relatively scarce and dispersed, information on malaria drug resistance in Angola, is reviewed and discussed. The review aims to inform but also to encourage future research studies that monitor and update the information on anti-malarial drug efficacy and prevalence of molecular markers of drug resistance, key fields in the context and objectives of elimination.
Topics: Angola; Antimalarials; Drug Resistance; Humans; Malaria, Falciparum; Plasmodium falciparum
PubMed: 26858018
DOI: 10.1186/s12936-016-1122-z -
Trends in Parasitology Feb 2020The major growth in point-of-care malaria diagnosis over the past decade has been based on immunochromatographic malaria rapid diagnostic tests (mRDTs), which generally... (Review)
Review
The major growth in point-of-care malaria diagnosis over the past decade has been based on immunochromatographic malaria rapid diagnostic tests (mRDTs), which generally detect Plasmodium falciparum via its abundant histidine-rich protein 2 (HRP2). Here, we review the discovery and biology of HRP2, as well as the strengths and weaknesses of HRP2-based diagnosis compared with alternative antigens. We highlight recent studies describing HRP2 deletion in Latin America, Eritrea, and possibly other regions, and the methodological challenges of confirming deletion of the pfhrp2 gene. We also discuss the mechanism of persistent HRP2 positivity after effective antimalarial treatment, along with other emerging HRP2-based applications, including detection of submicroscopic malaria and diagnosis of severe malaria.
Topics: Antigens, Protozoan; Gene Deletion; Humans; Malaria, Falciparum; Plasmodium falciparum; Protozoan Proteins; Research
PubMed: 31848119
DOI: 10.1016/j.pt.2019.12.004