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Proceedings of the National Academy of... Mar 2021Despite the critical role of sporozoites in malaria transmission, we still know little about the mechanisms underlying their development in mosquitoes. Here, we use...
Despite the critical role of sporozoites in malaria transmission, we still know little about the mechanisms underlying their development in mosquitoes. Here, we use single-cell RNA sequencing to characterize the gene expression profiles of 16,038 sporozoites isolated throughout their development from midgut oocysts to salivary glands, and from forced salivation experiments. Our results reveal a succession of tightly regulated changes in gene expression occurring during the maturation of sporozoites and highlight candidate genes that could play important roles in oocyst egress, sporozoite motility, and the mechanisms underlying the invasion of mosquito salivary glands and mammalian hepatocytes. In addition, the single-cell data reveal extensive transcriptional heterogeneity among parasites isolated from the same anatomical site, suggesting that development in mosquitoes is asynchronous and regulated by intrinsic as well as environmental factors. Finally, our analyses show a decrease in transcriptional activity preceding the translational repression observed in mature sporozoites and associated with their quiescent state in salivary glands, followed by a rapid reactivation of the transcriptional machinery immediately upon salivation.
Topics: Animals; Anopheles; Gene Expression Regulation; Mice; Plasmodium berghei; Salivary Glands; Sporozoites; Transcription, Genetic
PubMed: 33653959
DOI: 10.1073/pnas.2023438118 -
Scientific Reports Jun 2022Saccharum officinarum Linn. (sugarcane, Family-Poaceae) is employed in Ibibio traditional medicine for the treatment of various infections and diseases such as malaria....
Saccharum officinarum Linn. (sugarcane, Family-Poaceae) is employed in Ibibio traditional medicine for the treatment of various infections and diseases such as malaria. We This study aims to assess the antiplasmodial effect of the leaf extract and fractions on human malaria parasite (Plasmodium falciparum) in vitro, and rodent malaria parasite (P. berghei) in vivo, and analyse the bioactive components of the active fraction(s). The leaf extract and fractions of S. officinarum were prepared and their growth inhibitory effects tested against the chloroquine resistant P. falciparum strain (Dd2) and P. berghei infection in mice. An acute toxicity of the extract was determined. A combination of gas chromatography and liquid chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy was applied for metabolites profiling of crude extract and active fractions. The leaf extract and fractions demonstrated moderate activity against P. falciparum with the dichloromethane fraction producing the most potent activity (EC = 15.4 µg/mL). The leaf extract (170-510 mg/kg, p.o., LD = 1732 mg/kg) and fractions demonstrated significant (p < 0.05-0.001) effect on P. berghei infection in prophylactic tests as well as in established infection with n-butanol fractions producing the highest effect. An unusual sulphur-containing compound, dilaurylthiodipropionate, fatty acids, phenolic acids, flavonoid and flavonoid glycoside were identified in the active fractions. These results give credence to the use of sugarcane leaves as malarial remedy locally by confirming the in vitro and in vivo antiplasmodial potential of leaf extract/fractions of S. officinarum.
Topics: Animals; Antimalarials; Flavonoids; Folic Acid Antagonists; Malaria; Mice; Plant Extracts; Plant Leaves; Plasmodium berghei; Plasmodium falciparum; Saccharum
PubMed: 35715548
DOI: 10.1038/s41598-022-14391-8 -
Trends in Parasitology May 2023Chora and colleagues show that infection of the liver by Plasmodium modulates severity of disease in the experimental cerebral malaria (ECM) model by generating gamma...
Chora and colleagues show that infection of the liver by Plasmodium modulates severity of disease in the experimental cerebral malaria (ECM) model by generating gamma delta (ɣδ) T cells that produce IL-17. This work calls into question the long-standing assumption that liver infection does not modulate severity of malaria.
Topics: Humans; Plasmodium berghei; Malaria, Cerebral; Liver Diseases; Communicable Diseases
PubMed: 36935339
DOI: 10.1016/j.pt.2023.03.004 -
Journal of Ethnopharmacology Sep 2021Malaria remains one of the most prevalent infectious diseases in tropical regions of the world, particularly in sub-Saharan Africa, where it remains epidemiologically... (Comparative Study)
Comparative Study
ETHNOPHARMACOLOGICAL RELEVANCE
Malaria remains one of the most prevalent infectious diseases in tropical regions of the world, particularly in sub-Saharan Africa, where it remains epidemiologically holoendemic. The absence of effective vaccines and Plasmodium resistance to antimalarial drugs have been the major challenges to malaria control measures. An alternative strategy could be the application of validated and standardized herbal formulations.
AIM OF THE STUDY
To evaluate the antimalarial activity of a polyherbal mixture (APM) and compare it to those of its individual constituent plants.
METHODS
APM consisted of stem barks of Mangifera indica (MI), Azadirachta indica (AI), Nauclea latifolia (and roots, NL) and roots of Morinda lucida (ML). Dihydroartemisinin-piperaquine (DHP) and pyronaridine-artesunate (PA) served as positive controls. Antimalarial activity was evaluated using suppressive, curative and prophylactic assays in mice infected with Plasmodium berghei.
RESULTS
All the herbal mixtures, individually and in combination, showed significant (p < 0.05) antiplasmodial activities in the various assays. They produced considerable parasite suppression (>50%), substantial clearance (>70%), and notable prophylaxis (>60%, except for NL: 35%). APM (95.4-98.7%) and AI (92%), respectively, elicited greater and comparable suppression relative to DHP (88%) and PA (87.3%). However, all the herbal decoctions, individually (72-93.6%) and in combination (82.5-91%), showed lower parasite clearance than DHP (100%) and PA (99.5%). Meanwhile, APM showed relatively greater suppression and prophylaxis than its constituent plants, suggesting that the combination produced synergistic or additive effects.
CONCLUSION
These findings could substantiate the use of these plants, singly or in combination, as traditional remedies for malaria. Further studies are recommended to evaluate their clinical usefulness.
Topics: Animals; Antimalarials; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Female; Malaria; Male; Mice; Plant Extracts; Plants, Medicinal; Plasmodium berghei
PubMed: 33961995
DOI: 10.1016/j.jep.2021.114105 -
The Korean Journal of Parasitology Oct 2022The development of drug resistance is one of the most severe concerns of malaria control because it increases the risk of malaria morbidity and death. A new candidate...
Antimalarial Efficacy of Aqueous Extract of Strychnos ligustrina and Its Combination with Dihydroartemisinin and Piperaquine Phosphate (DHP) against Plasmodium berghei Infection.
The development of drug resistance is one of the most severe concerns of malaria control because it increases the risk of malaria morbidity and death. A new candidate drug with antiplasmodial activity is urgently needed. This study evaluated the efficacy of different dosages of aqueous extract of Strychnos ligustrina combined with dihydroartemisinin and piperaquine phosphate (DHP) against murine Plasmodium berghei infection. The BALB/c mice aged 6-8 weeks were divided into 6 groups, each consisting of 10 mice. The growth inhibition of compounds against P. berghei was monitored by calculating the percentage of parasitemia. The results showed that the mice receiving aqueous extract and combination treatment showed growth inhibition of P. berghei in 74% and 94%, respectively. S. ligustrina extract, which consisted of brucine and strychnine, effectively inhibited the multiplication of P. berghei. The treated mice showed improved hematology profiles, body weight, and temperature, as compared to control mice. Co-treatment with S. ligustrina extract and DHP revealed significant antimalarial and antipyretic effects. Our results provide prospects for further discovery of antimalarial drugs that may show more successful chemotherapeutic treatment.
Topics: Mice; Animals; Antimalarials; Plasmodium berghei; Strychnos; Plant Extracts; Malaria; Artemisinins; Mice, Inbred BALB C; Phosphates
PubMed: 36320110
DOI: 10.3347/kjp.2022.60.5.339 -
Parasitology International Jun 2020G-strand binding protein 2 (GBP2) is a Ser/Arg-rich (SR) protein involved in mRNA surveillance and nuclear mRNA quality control in yeast. However, the roles of GBP2 in... (Comparative Study)
Comparative Study
G-strand binding protein 2 (GBP2) is a Ser/Arg-rich (SR) protein involved in mRNA surveillance and nuclear mRNA quality control in yeast. However, the roles of GBP2 in virulence and sexual development in Plasmodium parasites are unclear, although GBP2 is involved in the asexual development of Plasmodium berghei, the rodent malaria parasite. In this study, we investigated the role of GBP2 in virulence and sexual development of P. berghei using gbp2-deleted P. berghei (Δgbp2 parasites). Then, to identify factors affected by gbp2 deletion, we performed a comparative proteomic analysis of the Δgbp2 parasites. We found that GBP2 was not associated with the development of experimental cerebral malaria during infection with P. berghei, but asexual development of the parasite was delayed with deletion of gbp2. However, the development of P. berghei gametocytes was significantly reduced with deletion of gbp2. Comparative proteomic analysis revealed that the levels of adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), and hypoxanthine-guanine phosphoribosyltransferase (HGPRT) in Δgbp2 parasites were significantly higher than those in wild-type (WT) parasites, suggesting that biosynthesis of purine nucleotides may be involved in function of GBP2. Therefore, we investigated the effect of purine starvation on the sexual development and proteome. In nt1-deleted P. berghei (Δnt1 parasites), the production of male and female gametocytes was significantly reduced compared to that in WT parasites. Moreover, we found that protein levels of GBP2 in Δnt1 parasites were markedly lower than in WT parasites. These findings suggest that GBP2 is primarily involved in the sexual development of malaria parasites, and its function may be suppressed by purine starvation.
Topics: Animals; Erythrocytes; Female; Gene Deletion; Malaria, Cerebral; Mice; Mice, Inbred C57BL; Plasmodium berghei; Proteomics; Protozoan Proteins; Purine Nucleotides; Specific Pathogen-Free Organisms
PubMed: 31958569
DOI: 10.1016/j.parint.2020.102059 -
PLoS Pathogens Sep 2020Professional antigen-presenting cells (APCs), like macrophages (Mϕs) and dendritic cells (DCs), are central players in the induction of natural and vaccine-induced...
Professional antigen-presenting cells (APCs), like macrophages (Mϕs) and dendritic cells (DCs), are central players in the induction of natural and vaccine-induced immunity to malaria, yet very little is known about the interaction of SPZ with human APCs. Intradermal delivery of whole-sporozoite vaccines reduces their effectivity, possibly due to dermal immunoregulatory effects. Therefore, understanding these interactions could prove pivotal to malaria vaccination. We investigated human APC responses to recombinant circumsporozoite protein (recCSP), SPZ and anti-CSP opsonized SPZ both in monocyte derived MoDCs and MoMϕs. Both MoDCs and MoMϕs readily took up recCSP but did not change phenotype or function upon doing so. SPZ are preferentially phagocytosed by MoMϕs instead of DCs and phagocytosis greatly increased after opsonization. Subsequently MoMϕs show increased surface marker expression of activation markers as well as tolerogenic markers such as Programmed Death-Ligand 1 (PD-L1). Additionally they show reduced motility, produce interleukin 10 and suppressed interferon gamma (IFNγ) production by antigen specific CD8+ T cells. Importantly, we investigated phenotypic responses to SPZ in primary dermal APCs isolated from human skin explants, which respond similarly to their monocyte-derived counterparts. These findings are a first step in enhancing our understanding of pre-erythrocytic natural immunity and the pitfalls of intradermal vaccination-induced immunity.
Topics: Animals; Antigen-Presenting Cells; Cells, Cultured; Female; Humans; Macrophages; Malaria; Mice; Plasmodium berghei; Protozoan Proteins; Skin; Sporozoites
PubMed: 32898164
DOI: 10.1371/journal.ppat.1008799 -
Nature Communications Mar 2023Malaria-causing parasites of the Plasmodium genus undergo multiple developmental phases in the human and the mosquito hosts, regulated by various post-translational...
Malaria-causing parasites of the Plasmodium genus undergo multiple developmental phases in the human and the mosquito hosts, regulated by various post-translational modifications. While ubiquitination by multi-component E3 ligases is key to regulate a wide range of cellular processes in eukaryotes, little is known about its role in Plasmodium. Here we show that Plasmodium berghei expresses a conserved SKP1/Cullin1/FBXO1 (SCF) complex showing tightly regulated expression and localisation across multiple developmental stages. It is key to cell division for nuclear segregation during schizogony and centrosome partitioning during microgametogenesis. It is additionally required for parasite-specific processes including gamete egress from the host erythrocyte, as well as integrity of the apical and the inner membrane complexes (IMC) in merozoite and ookinete, two structures essential for the dissemination of these motile stages. Ubiquitinomic surveys reveal a large set of proteins ubiquitinated in a FBXO1-dependent manner including proteins important for egress and IMC organisation. We additionally demonstrate an interplay between FBXO1-dependent ubiquitination and phosphorylation via calcium-dependent protein kinase 1. Altogether we show that Plasmodium SCF plays conserved roles in cell division and is also important for parasite-specific processes in the mammalian and mosquito hosts.
Topics: Humans; Erythrocytes; Plasmodium berghei; Protein Binding; S-Phase Kinase-Associated Proteins; Ubiquitination
PubMed: 36898988
DOI: 10.1038/s41467-023-36999-8 -
Methods in Molecular Biology (Clifton,... 2021Genome editing in the malaria parasite Plasmodium relies on homologous recombination and requires parasite transfection in asexual blood stages. Therefore, conditional...
Genome editing in the malaria parasite Plasmodium relies on homologous recombination and requires parasite transfection in asexual blood stages. Therefore, conditional genetic approaches are needed to delete genes that are essential during blood stage replication. Among these, the dimerizable Cre (DiCre) recombinase system has emerged as a powerful approach for conditional gene knockout in Plasmodium parasites. In this system, the Cre recombinase is expressed in the form of two separate, enzymatically inactive polypeptides. Rapamycin-induced heterodimerization of the two components restores recombinase activity, leading to site-specific excision of floxed DNA sequences. Here, we describe methods to generate genetically modified DiCre-expressing Plasmodium berghei mutants by introducing Lox sites upstream and downstream of a gene of interest and to induce conditional excision of the floxed gene in different stages of the parasite life cycle. Administration of rapamycin to P. berghei-infected mice allows conditional gene deletion in the asexual erythrocytic stages. Rapamycin-induced gene excision can also be achieved in P. berghei sexual blood stages prior to transmission to mosquitoes, or during sporogony by treating P. berghei-infected mosquitoes, both methods allowing functional studies in P. berghei mosquito stages. Finally, rapamycin can be administered to in vitro cell cultures in order to induce gene excision in P. berghei liver stages. Subsequent phenotyping allows for the analysis of essential gene function across the parasite life cycle stages.
Topics: Animals; Culicidae; Gene Deletion; Integrases; Life Cycle Stages; Mice; Plasmodium berghei; Sirolimus
PubMed: 34313986
DOI: 10.1007/978-1-0716-1681-9_7 -
Biomedical Chromatography : BMC Mar 2023Our previous work revealed mutual and specific metabolites/pathways in artemisinin-sensitive and -resistant Plasmodium berghei K173-infected mice. In this study, we...
Nontargeted metabolomics integrated with H NMR and LC-Q-TOF-MS/MS methods to depict a more comprehensive metabolic profile in response to chrysosplenetin and artemisinin co-treatment against artemisinin-sensitive and -resistant Plasmodium berghei K173.
Our previous work revealed mutual and specific metabolites/pathways in artemisinin-sensitive and -resistant Plasmodium berghei K173-infected mice. In this study, we further investigated whether chrysosplenetin, a candidate chemical to prevent artemisinin resistance, can regulate these metabolites/pathways by integrating nontargeted metabolomics with H NMR and LC-Q-TOF-MS/MS spectrum. The nuclear magnetic resonance method generated specifically altered metabolites in response to co-treatment with chrysosplenetin, including: the products of glycolysis such as glucose, pyruvate, lactate and alanine; taurine, closely associated with liver injury; arginine and proline as essential amino acids for parasites; TMAO, a biomarker for dysbacteriosis and renal function; and tyrosine, which is used to generate levodopa and dopamine and may improve the torpor state of mice. Importantly, we noticed that chrysosplenetin might depress the activated glycolysis induced by sensitive parasites, but oppositely promoted the inhibited glycolysis to generate more lactate, which suppresses the proliferation of resistant parasites. Moreover, chrysosplentin possibly disturbs the heme biosynthetic pathway in mitochondria. The MS method yielded changed coenzyme A, phosphatidylcholine and ceramides, closely related to mitochondria β-oxidation, cell proliferation, differentiation and apoptosis. These two means shared no overlapped metabolites and formed a more broader metabolic map to study the potential mechanisms of chrysosplenetin as a promising artemisinin resistance inhibitor.
Topics: Mice; Animals; Plasmodium berghei; Tandem Mass Spectrometry; Artemisinins; Metabolomics; Metabolome; Magnetic Resonance Spectroscopy
PubMed: 36471489
DOI: 10.1002/bmc.5561