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Journal of Cheminformatics May 2024Drug discovery is an intricate and costly process. Repurposing existing drugs and active compounds offers a viable pathway to develop new therapies for various diseases....
Drug discovery is an intricate and costly process. Repurposing existing drugs and active compounds offers a viable pathway to develop new therapies for various diseases. By leveraging publicly available biomedical information, it is possible to predict compounds' activity and identify their potential targets across diverse organisms. In this study, we aimed to assess the antiplasmodial activity of compounds from the Repurposing, Focused Rescue, and Accelerated Medchem (ReFRAME) library using in vitro and bioinformatics approaches. We assessed the in vitro antiplasmodial activity of the compounds using blood-stage and liver-stage drug susceptibility assays. We used protein sequences of known targets of the ReFRAME compounds with high antiplasmodial activity (EC < 10 uM) to conduct a protein-pairwise search to identify similar Plasmodium falciparum 3D7 proteins (from PlasmoDB) using NCBI protein BLAST. We further assessed the association between the compounds' in vitro antiplasmodial activity and level of similarity between their known and predicted P. falciparum target proteins using simple linear regression analyses. BLAST analyses revealed 735 P. falciparum proteins that were similar to the 226 known protein targets associated with the ReFRAME compounds. Antiplasmodial activity of the compounds was positively associated with the degree of similarity between the compounds' known targets and predicted P. falciparum protein targets (percentage identity, E value, and bit score), the number of the predicted P. falciparum targets, and their respective mutagenesis index and fitness scores (R between 0.066 and 0.92, P < 0.05). Compounds predicted to target essential P. falciparum proteins or those with a druggability index of 1 showed the highest antiplasmodial activity.
PubMed: 38831351
DOI: 10.1186/s13321-024-00856-7 -
PLoS Pathogens Jun 2024Asexual replication of Plasmodium falciparum occurs via schizogony, wherein 16-36 daughter cells are produced within the parasite during one semi-synchronized...
Asexual replication of Plasmodium falciparum occurs via schizogony, wherein 16-36 daughter cells are produced within the parasite during one semi-synchronized cytokinetic event. Schizogony requires a divergent contractile ring structure known as the basal complex. Our lab has previously identified PfMyoJ (PF3D7_1229800) and PfSLACR (PF3D7_0214700) as basal complex proteins recruited midway through segmentation. Using ultrastructure expansion microscopy, we localized both proteins to a novel basal complex subcompartment. While both colocalize with the basal complex protein PfCINCH upon recruitment, they form a separate, more basal subcompartment termed the posterior cup during contraction. We also show that PfSLACR is recruited to the basal complex prior to PfMyoJ, and that both proteins are removed unevenly as segmentation concludes. Using live-cell microscopy, we show that actin dynamics are dispensable for basal complex formation, expansion, and contraction. We then show that EF-hand containing P. falciparum Centrin 2 partially localizes to this posterior cup of the basal complex and that it is essential for growth and replication, with variable defects in basal complex contraction and synchrony. Finally, we demonstrate that free intracellular calcium is necessary but not sufficient for basal complex contraction in P. falciparum. Thus, we demonstrate dynamic spatial compartmentalization of the Plasmodium falciparum basal complex, identify an additional basal complex protein, and begin to elucidate the unique mechanism of contraction utilized by P. falciparum, opening the door for further exploration of Apicomplexan cellular division.
Topics: Plasmodium falciparum; Protozoan Proteins; Malaria, Falciparum; Humans; Erythrocytes
PubMed: 38829893
DOI: 10.1371/journal.ppat.1012265 -
PloS One 2024Malaria is a deadly disease that is transmitted through mosquito bites. Microscopists use a microscope to examine thin blood smears at high magnification (1000x) to... (Comparative Study)
Comparative Study
Malaria is a deadly disease that is transmitted through mosquito bites. Microscopists use a microscope to examine thin blood smears at high magnification (1000x) to identify parasites in red blood cells (RBCs). Estimating parasitemia is essential in determining the severity of the Plasmodium falciparum infection and guiding treatment. However, this process is time-consuming, labor-intensive, and subject to variation, which can directly affect patient outcomes. In this retrospective study, we compared three methods for measuring parasitemia from a collection of anonymized thin blood smears of patients with Plasmodium falciparum obtained from the Clinical Department of Parasitology-Mycology, National Reference Center (NRC) for Malaria in Paris, France. We first analyzed the impact of the number of field images on parasitemia count using our framework, MALARIS, which features a top-classifier convolutional neural network (CNN). Additionally, we studied the variation between different microscopists using two manual techniques to demonstrate the need for a reliable and reproducible automated system. Finally, we included thin blood smear images from an additional 102 patients to compare the performance and correlation of our system with manual microscopy and flow cytometry. Our results showed strong correlations between the three methods, with a coefficient of determination between 0.87 and 0.92.
Topics: Humans; Plasmodium falciparum; Parasitemia; Malaria, Falciparum; Retrospective Studies; Microscopy; Erythrocytes; Image Processing, Computer-Assisted; Neural Networks, Computer; Flow Cytometry
PubMed: 38829858
DOI: 10.1371/journal.pone.0304789 -
Frontiers in Cellular and Infection... 2024Recent studies indicate that human spleen contains over 95% of the total parasite biomass during chronic asymptomatic infections caused by . Previous studies have...
Recent studies indicate that human spleen contains over 95% of the total parasite biomass during chronic asymptomatic infections caused by . Previous studies have demonstrated that extracellular vesicles (EVs) secreted from infected reticulocytes facilitate binding to human spleen fibroblasts (hSFs) and identified parasite genes whose expression was dependent on an intact spleen. Here, we characterize the spleen-dependent hypothetical gene (PVX_114580). Using CRISPR/Cas9, PVX_114580 was integrated into 3D7 genome and expressed during asexual stages. Immunofluorescence analysis demonstrated that the protein, which we named (PvSDP1), was located at the surface of infected red blood cells in the transgenic line and this localization was later confirmed in natural infections. Plasma-derived EVs from -infected individuals (PvEVs) significantly increased cytoadherence of 3D7_PvSDP1 transgenic line to hSFs and this binding was inhibited by anti-PvSDP1 antibodies. Single-cell RNAseq of PvEVs-treated hSFs revealed increased expression of adhesion-related genes. These findings demonstrate the importance of parasite spleen-dependent genes and EVs from natural infections in the formation of intrasplenic niches in , a major challenge for malaria elimination.
Topics: Extracellular Vesicles; Plasmodium vivax; Humans; Spleen; Malaria, Vivax; Protozoan Proteins; Erythrocytes; Fibroblasts; Plasmodium falciparum; Cell Adhesion; Host-Parasite Interactions
PubMed: 38828264
DOI: 10.3389/fcimb.2024.1408451 -
Risk Management and Healthcare Policy 2024Malaria is one of the most widespread infections worldwide, particularly in developing countries. Accordingly, Jimma Zone is one of the widely affected areas by malaria...
BACKGROUND
Malaria is one of the most widespread infections worldwide, particularly in developing countries. Accordingly, Jimma Zone is one of the widely affected areas by malaria in Ethiopia. In 2020 woreda health offices have reported the possible malaria epidemic that needs further investigation. Accordingly, this study aims to characterize the scope, pinpoint determinants connected to the Nono Benja woreda malaria outbreak, and implement suitable public health management measures.
METHODS
A descriptive cross-sectional study was followed by an unmatched case-control study with a 1:1 ratio of cases to controls. The sample size of 136 individuals (68 cases and 68 controls) was used. The collected data was imported into Epi-data version 3.1 and analyzed using SPSS version 25.0. By doing multivariate logistic regression association was determined at 95% confidence intervals P value of 5%.
RESULTS
A total of 687 instances were identified, giving an overall attack incidence of 1%. The assault rate ranged from 51.6 per 1000 people in Benja rural to 1.1 per 1000 people in Dhokonu Kebele. But there were no recorded deaths. and were the major types of Plasmodium species reported. From independent variables absence of ITNS [AOR 3.98 (CI = 1.11-24.8)], residing in an unsprayed home [AOR = 3.83 (CI = 1.04-14.08], presence of stagnant water in residential area [AOR = 4.25, CI (1.37-12.24113.10)], and lack of awareness on malaria prevention [AOR = 8.28 (CI 2.31-29.73)] were significantly associated with Malaria outbreak.
CONCLUSION
A number of factors, including lack of ITNS, lack of malaria health education, stagnant water, and IRS (indoor residual spray), were significantly linked with the occurrence of malaria outbreaks. The woreda health office should therefore provide ITNS to the community, use indoor residual spray, and disseminate health information regarding efficient and long-lasting malaria preventive and control techniques.
PubMed: 38828105
DOI: 10.2147/RMHP.S456958 -
Frontiers in Immunology 2024Depending on the microenvironment, γδ T cells may assume characteristics similar to those of Th1, Th2, Th17, regulatory T cells or antigen presenting cells. Despite...
INTRODUCTION
Depending on the microenvironment, γδ T cells may assume characteristics similar to those of Th1, Th2, Th17, regulatory T cells or antigen presenting cells. Despite the wide documentation of the effect of Th1/Th2 balance on pregnancy associated malaria and outcomes, there are no reports on the relationship between γδ T cell phenotype change and Placental Malaria (PM) with pregnancy outcomes. This study sought to investigate the involvement of γδ T cells and its subsets in placental malaria.
METHODS
In a case-control study conducted in Yaoundé, Cameroon from March 2022 to May 2023, peripheral, placental and cord blood samples were collected from 50 women at delivery (29 PM negative: PM- and 21 PM positive: PM+; as diagnosed by light microscopy). Hemoglobin levels were measured using hemoglobinometer. PBMCs, IVBMCs and CBMCs were isolated using histopaque-1077 and used to characterize total γδ T cell populations and subsets (Vδ1, Vδ2, Vδ1Vδ2) by flow cytometry.
RESULTS
Placental infection was associated with significant increase in the frequency of total γδ T cells in IVBMC and of the Vδ1 subset in PBMC and IVBMC, but decreased frequency of the Vδ2 subset in PBMC and IVBMC. The expression of the activation marker: HLA-DR, and the exhaustion markers (PD1 and TIM3) within total γδ T cells and subsets were significantly up-regulated in PM+ compared to PM- group. The frequency of total γδ T cells in IVBMC, TIM-3 expression within total γδ T cells and subsets in IVBMC, as well as HLA-DR expression within total γδ T cells and Vδ2 subset in IVBMC were negatively associated with maternal hemoglobin levels. Furthermore, the frequency of total γδ T cells in PBMC and PD1 expression within the Vδ2 subset in CBMC were negatively associated with birth weight contrary to the frequency of Vδ1Vδ2 subset in PBMC and HLA-DR expression within the Vδ2 subset in IVBMC which positively associated with maternal hemoglobin level and birth weight, respectively.
CONCLUSION
The data indicate up-regulation of activated and exhausted γδ T cells in placental malaria, with effects on pregnancy outcomes including maternal hemoglobin level and birth weight.
Topics: Humans; Female; Pregnancy; Malaria, Falciparum; Cameroon; Adult; Receptors, Antigen, T-Cell, gamma-delta; Plasmodium falciparum; Pregnancy Complications, Parasitic; Case-Control Studies; Pregnancy Outcome; Young Adult; Placenta; T-Lymphocyte Subsets; Phenotype
PubMed: 38827744
DOI: 10.3389/fimmu.2024.1385380 -
ACS Omega May 2024Malaria, caused by Plasmodium protozoa with as the most virulent species, continues to pose significant health challenges. Despite the availability of effective...
Malaria, caused by Plasmodium protozoa with as the most virulent species, continues to pose significant health challenges. Despite the availability of effective antimalarial drugs, the emergence of resistance has heightened the urgency for developing novel therapeutic compounds. In this study, we investigated the enoyl-ACP reductase enzyme of (PfENR) as a promising target for antimalarial drug discovery. Through a comprehensive analysis, we conducted a comparative evaluation of two lead compounds, LD1 (CID: 44405336, lead compounds 1) and LD2 (CID: 72703246, lead compounds 2), obtained from the PubChem/NCBI ligand database, to serve as reference molecules in the identification of potential derivatives using virtual screening assays. Among the newly identified candidates, Ligand 1 (LG1) and Ligand 2 (LG2) exhibited intriguing characteristics and underwent further investigation through docking and molecular dynamics simulations. Ligand 1 (LG1) demonstrated interactions similar to LD1, including hydrogen bonding with Asp218, while Ligand 2 (LG2) displayed superior binding energy comparable to LD1 and LD2, despite lacking hydrogen bonding interactions observed in the control compounds triclosan and its derivative 7-(4-chloro-2-hydroxyphenoxy)-4-methyl-2H-chromen-2-one (CHJ). Following computational validation using the MM/GBSA method to estimate binding free energy, commercially acquired LG1 and LG2 ligands were subjected to in vitro testing. Inhibition assays were performed to evaluate their potential as PfENR inhibitors alongside triclosan as a control compound. LG1 exhibited no inhibitory effects, while LG2 demonstrated inhibitory effects like triclosan. In conclusion, this study contributes valuable insights into developing novel antimalarial drugs by identifying LG2 as a potential ligand and employing a comprehensive approach integrating computational and experimental methodologies.
PubMed: 38826533
DOI: 10.1021/acsomega.3c09893 -
BioRxiv : the Preprint Server For... May 2024Glycosylphosphatidylinositol (GPI) anchor protein modification in species is well known and represents the principal form of glycosylation in these organisms. The...
Glycosylphosphatidylinositol (GPI) anchor protein modification in species is well known and represents the principal form of glycosylation in these organisms. The structure and biosynthesis of GPI anchors of spp. has been primarily studied in the asexual blood stage of and is known to contain the typical conserved GPI structure of EtN-P-Man3GlcN-PI. Here, we have investigated the circumsporozoite protein (CSP) for the presence of a GPI-anchor. CSP is the major surface protein of sporozoites, the infective stage of the malaria parasite. While it is widely assumed that CSP is a GPI-anchored cell surface protein, compelling biochemical evidence for this supposition is absent. Here, we employed metabolic labeling and mass-spectrometry based approaches to confirm the presence of a GPI anchor in CSP. Biosynthetic radiolabeling of CSP with [ H]-palmitic acid and [ H]-ethanolamine, with the former being base-labile and therefore ester-linked, provided strong evidence for the presence of a GPI anchor on CSP, but these data alone were not definitive. To provide further evidence, immunoprecipitated CSP was analyzed for presence of -inositol (a characteristic component of GPI anchor) using strong acid hydrolysis and GC-MS for a highly sensitive and quantitative detection. The single ion monitoring (SIM) method for GC-MS analysis confirmed the presence of the -inositol component in CSP. Taken together, these data provide confidence that the long-assumed presence of a GPI anchor on this important parasite protein is correct.
PubMed: 38826328
DOI: 10.1101/2024.05.21.595204 -
Molecular and Biochemical Parasitology Sep 2024Asexual blood stage culture of Plasmodium falciparum is routinely performed but reproducibly inducing commitment to and maturation of viable gametocytes remains...
Asexual blood stage culture of Plasmodium falciparum is routinely performed but reproducibly inducing commitment to and maturation of viable gametocytes remains difficult. Culture media can be supplemented with human serum substitutes to induce commitment but these generally only allow for long-term culture of asexual parasites and not transmission-competent gametocytes due to their different lipid composition. Recent insights demonstrated the important roles lipids play in sexual commitment; elaborating on this we exposed ring stage parasites (20-24 hours hpi) for one day to AlbuMAX supplemented media to trigger induction to gametocytogenesis. We observed a significant increase in gametocytes after AlbuMAX induction compared to serum. We also tested the transmission potential of AlbuMAX inducted gametocytes and found a significant higher oocyst intensity compared to serum. We conclude that AlbuMAX supplemented media induces commitment, allows a more stable and predictable production of transmittable gametocytes than serum alone.
Topics: Plasmodium falciparum; Culture Media; Humans; Malaria, Falciparum
PubMed: 38823647
DOI: 10.1016/j.molbiopara.2024.111634 -
PLoS Biology May 2024Vesicular trafficking, including secretion and endocytosis, plays fundamental roles in the unique biology of Plasmodium falciparum blood-stage parasites. Endocytosis of...
Vesicular trafficking, including secretion and endocytosis, plays fundamental roles in the unique biology of Plasmodium falciparum blood-stage parasites. Endocytosis of host cell cytosol (HCC) provides nutrients and room for parasite growth and is critical for the action of antimalarial drugs and parasite drug resistance. Previous work showed that PfVPS45 functions in endosomal transport of HCC to the parasite's food vacuole, raising the possibility that malaria parasites possess a canonical endolysosomal system. However, the seeming absence of VPS45-typical functional interactors such as rabenosyn 5 (Rbsn5) and the repurposing of Rab5 isoforms and other endolysosomal proteins for secretion in apicomplexans question this idea. Here, we identified a parasite Rbsn5-like protein and show that it functions with VPS45 in the endosomal transport of HCC. We also show that PfRab5b but not PfRab5a is involved in the same process. Inactivation of PfRbsn5L resulted in PI3P and PfRab5b decorated HCC-filled vesicles, typical for endosomal compartments. Overall, this indicates that despite the low sequence conservation of PfRbsn5L and the unusual N-terminal modification of PfRab5b, principles of endosomal transport in malaria parasite are similar to that of model organisms. Using a conditional double protein inactivation system, we further provide evidence that the PfKelch13 compartment, an unusual apicomplexa-specific endocytosis structure at the parasite plasma membrane, is connected upstream of the Rbsn5L/VPS45/Rab5b-dependent endosomal route. Altogether, this work indicates that HCC uptake consists of a highly parasite-specific part that feeds endocytosed material into an endosomal system containing more canonical elements, leading to the delivery of HCC to the food vacuole.
Topics: rab5 GTP-Binding Proteins; Endosomes; Cytosol; Plasmodium falciparum; Humans; Protozoan Proteins; Endocytosis; Malaria, Falciparum; Vesicular Transport Proteins; Animals; Host-Parasite Interactions; Vacuoles; Erythrocytes; Protein Transport
PubMed: 38820535
DOI: 10.1371/journal.pbio.3002639