scholarly journals A Prioritized and Validated Resource of Mitochondrial Proteins in Plasmodium Identifies Unique Biology

mSphere ◽  
2021 ◽  
Author(s):  
Selma L. van Esveld ◽  
Lisette Meerstein‐Kessel ◽  
Cas Boshoven ◽  
Jochem F. Baaij ◽  
Konstantin Barylyuk ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Parasite ◽  
Comprehensive Assessment ◽  
Mitochondrial Proteins ◽  
Content Type ◽  
Unique Biology ◽  
The Subject ◽  
Medical Relevance

The unique biology and medical relevance of the mitochondrion of the malaria parasite Plasmodium falciparum have made it the subject of many studies. However, we actually do not have a comprehensive assessment of which proteins reside in this organelle.

scholarly journals Artemisone and Artemiside Are Potent Panreactive Antimalarial Agents That Also Synergize Redox Imbalance in Plasmodium falciparum Transmissible Gametocyte Stages

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Dina Coertzen ◽  
Janette Reader ◽  
Mariëtte van der Watt ◽  
Sindisiwe H. Nondaba ◽  
Liezl Gibhard ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Control ◽  
Malaria Parasite ◽  
Redox Homeostasis ◽  
New Drugs ◽  
Content Type ◽  
Artemisinin Derivatives ◽  
Antimalarial Agents ◽  
Redox Partner ◽  
Emergence Of Resistance

ABSTRACT The emergence of resistance toward artemisinin combination therapies (ACTs) by the malaria parasite Plasmodium falciparum has the potential to severely compromise malaria control. Therefore, the development of new artemisinins in combination with new drugs that impart activities toward both intraerythrocytic proliferative asexual and transmissible gametocyte stages, in particular, those of resistant parasites, is urgently required. We define artemisinins as oxidant drugs through their ability to oxidize reduced flavin cofactors of flavin disulfide reductases critical for maintaining redox homeostasis in the malaria parasite. Here we compare the activities of 10-amino artemisinin derivatives toward the asexual and gametocyte stages of P. falciparum parasites. Of these, artemisone and artemiside inhibited asexual and gametocyte stages, particularly stage V gametocytes, in the low-nanomolar range. Further, treatment of both early and late gametocyte stages with artemisone or artemiside combined with the pro-oxidant redox partner methylene blue displayed notable synergism. These data suggest that modulation of redox homeostasis is likely an important druggable process, particularly in gametocytes, and this finding thereby enhances the prospect of using combinations of oxidant and redox drugs for malaria control.

scholarly journals Protein Prenylation and Hsp40 in Thermotolerance of Plasmodium falciparum Malaria Parasites

mBio ◽  
2021 ◽  
Author(s):  
Emily S. Mathews ◽  
Andrew J. Jezewski ◽  
Audrey R. Odom John
Keyword(s):  
Plasmodium Falciparum ◽  
Life Cycle ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Malaria Parasite ◽  
Plasmodium Falciparum Malaria ◽  
Complex Life Cycle ◽  
Large Temperature ◽  
Protein Prenylation ◽  
Content Type

During its complex life cycle, the malaria parasite survives dramatic environmental stresses, including large temperature shifts. Protein prenylation is required during asexual replication of Plasmodium falciparum , and the canonical heat shock protein 40 protein (HSP40; PF3D7_1437900) is posttranslationally modified with a 15-carbon farnesyl isoprenyl group.

scholarly journals Activity of Epigenetic Inhibitors against Plasmodium falciparum Asexual and Sexual Blood Stages

2020 ◽  
Vol 64 (7) ◽  
Author(s):  
Leen N. Vanheer ◽  
Hao Zhang ◽  
Gang Lin ◽  
Björn F. C. Kafsack
Keyword(s):  
Gene Expression ◽  
Plasmodium Falciparum ◽  
Epigenetic Regulation ◽  
Malaria Parasite ◽  
Regulation Of Gene Expression ◽  
Life Stages ◽  
Content Type ◽  
Promising Target ◽  
Parasite Survival ◽  
Multiple Stages

ABSTRACT Earlier genetic and inhibitor studies showed that epigenetic regulation of gene expression is critical for malaria parasite survival in multiple life stages and a promising target for new antimalarials. We therefore evaluated the activity of 350 diverse epigenetic inhibitors against multiple stages of Plasmodium falciparum. We observed ≥90% inhibition at 10 μM for 28% of compounds against asexual blood stages and early gametocytes, of which a third retained ≥90% inhibition at 1 μM.

scholarly journals Chloroquine Resistance-Conferring Mutations in pfcrt Give Rise to a Chloroquine-Associated H+ Leak from the Malaria Parasite's Digestive Vacuole

2008 ◽  
Vol 52 (12) ◽  
pp. 4374-4380 ◽  
Author(s):  
Adele M. Lehane ◽  
Kiaran Kirk
Keyword(s):  
Plasmodium Falciparum ◽  
Toxic Effect ◽  
Genetic Background ◽  
Malaria Parasite ◽  
Chloroquine Resistance ◽  
Digestive Vacuole ◽  
Ongoing Debate ◽  
The Subject ◽  
High Concentrations ◽  
Do So

ABSTRACT Chloroquine resistance in the malaria parasite Plasmodium falciparum is conferred by mutations in the P. falciparum chloroquine resistance transporter (PfCRT). PfCRT localizes to the membrane of the parasite's internal digestive vacuole, an acidic organelle in which chloroquine accumulates to high concentrations and exerts its toxic effect. Mutations in PfCRT are thought to reduce chloroquine accumulation in this organelle. How they do so is the subject of ongoing debate. Recently we have shown that in the presence of chloroquine there is an increased leak of H+ from the digestive vacuole in chloroquine-resistant but not chloroquine-sensitive parasites. Here, using transfectant parasite strains of a single genetic background and differing only in their pfcrt allele, we show that chloroquine resistance-conferring PfCRT mutations are responsible for this chloroquine-associated H+ leak. This is consistent with the hypothesis that the chloroquine resistance-conferring forms of PfCRT mediate the efflux of chloroquine, in association with H+, from the malaria parasite's digestive vacuole.

scholarly journals Radicicol-Mediated Inhibition of Topoisomerase VIB-VIA Activity of the Human Malaria Parasite Plasmodium falciparum

mSphere ◽  
2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Sureshkumar Chalapareddy ◽  
Swati Chakrabarty ◽  
Mrinal Kanti Bhattacharyya ◽  
Sunanda Bhattacharyya
Keyword(s):  
Plasmodium Falciparum ◽  
Protein Complex ◽  
Malaria Parasite ◽  
Specific Inhibitor ◽  
Assay System ◽  
Biochemical Assay ◽  
Dependent Manner ◽  
Human Malaria Parasite ◽  
Content Type ◽  
Human Malaria

ABSTRACT In this study we characterize topoisomerase VI from Plasmodium falciparum using genetic and biochemical approaches. We use various inhibitors and identify radicicol as a specific inhibitor of its decatenation activity. We establish a very simple and economical biochemical assay system that can be exploited to screen inhibitors of PfTopoVI. Plasmodium falciparum topoisomerase VIB (TopoVIB)-TopoVIA (TopoVIB-VIA) complex can be potentially exploited as a drug target against malaria due to its absence from the human genome. Previous work in our laboratory has suggested that P. falciparum TopoVIB (PfTopoVIB) might be a target of radicicol since treatment of parasite cultures with this antibiotic is associated with upregulation of Plasmodium TopoVIB at the transcript level as well as at the protein level. Further studies demonstrated that radicicol treatment impaired mitochondrial replication of human malaria parasite P. falciparum. However, the technical challenge associated with the expression of the above protein complex hampered its functional characterization. Using Saccharomyces cerevisiae as a heterologous system, we expressed PfTopoVIB (Myc-tagged) and PfTopoVIA (Flag-tagged) (PfTopoVIB-VIA) proteins. Yeast two-hybrid analysis showed the formation of PfTopoVIB homodimers and PfTopoVIB/PfTopoVIA heteromers. Our study demonstrated that PfTopoVIB and PfTopoVIA together can rescue the lethal phenotype of yeast ΔtopoII mutants, whereas Plasmodium topoisomerase VIB alone cannot. Using yeast cell-free extracts harboring the PfTopoVIB-VIA protein complex, we have performed a decatenation assay and observed that PfTopoVIB-VIA can decatenate DNA in an ATP- and Mg2+-dependent manner. The specificity of this enzyme is established by abrogation of its activity in the presence of PfTopoVIB-specific antibody. Our study results show that radicicol and etoposide can specifically inhibit PfTopoVIB-VIA decatenation activity whereas the gyrase inhibitor novobiocin cannot. Such a yeast-based assay system can be employed in screening specific inhibitors against Plasmodium VIB-VIA. IMPORTANCE In this study we characterize topoisomerase VI from Plasmodium falciparum using genetic and biochemical approaches. We use various inhibitors and identify radicicol as a specific inhibitor of its decatenation activity. We establish a very simple and economical biochemical assay system that can be exploited to screen inhibitors of PfTopoVI.

scholarly journals CRISPR Interference of a Clonally Variant GC-Rich Noncoding RNA Family Leads to General Repression of var Genes in Plasmodium falciparum

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Anna Barcons-Simon ◽  
Carlos Cordon-Obras ◽  
Julien Guizetti ◽  
Jessica M. Bryant ◽  
Artur Scherf
Keyword(s):  
Plasmodium Falciparum ◽  
Gene Family ◽  
Immune Evasion ◽  
Noncoding Rna ◽  
Malaria Parasite ◽  
Antigenic Variation ◽  
Activation Mechanism ◽  
Regulation Mechanism ◽  
Content Type ◽  
Crispr Interference

ABSTRACT The human malaria parasite Plasmodium falciparum uses mutually exclusive expression of the PfEMP1-encoding var gene family to evade the host immune system. Despite progress in the molecular understanding of the default silencing mechanism, the activation mechanism of the uniquely expressed var member remains elusive. A GC-rich noncoding RNA (ncRNA) gene family has coevolved with Plasmodium species that express var genes. Here, we show that this ncRNA family is transcribed in a clonally variant manner, with predominant transcription of a single member occurring when the ncRNA is located adjacent to and upstream of an active var gene. We developed a specific CRISPR interference (CRISPRi) strategy that allowed for the transcriptional repression of all GC-rich members. A lack of GC-rich ncRNA transcription led to the downregulation of the entire var gene family in ring-stage parasites. Strikingly, in mature blood-stage parasites, the GC-rich ncRNA CRISPRi affected the transcription patterns of other clonally variant gene families, including the downregulation of all Pfmc-2TM members. We provide evidence for the key role of GC-rich ncRNA transcription in var gene activation and discovered a molecular link between the transcriptional control of various clonally variant multigene families involved in parasite virulence. This work opens new avenues for elucidating the molecular processes that control immune evasion and pathogenesis in P. falciparum. IMPORTANCE Plasmodium falciparum is the deadliest malaria parasite species, accounting for the vast majority of disease cases and deaths. The virulence of this parasite is reliant upon the mutually exclusive expression of cytoadherence proteins encoded by the 60-member var gene family. Antigenic variation of this multigene family serves as an immune evasion mechanism, ultimately leading to chronic infection and pathogenesis. Understanding the regulation mechanism of antigenic variation is key to developing new therapeutic and control strategies. Our study uncovers a novel layer in the epigenetic regulation of transcription of this family of virulence genes by means of a multigene-targeting CRISPR interference approach.

scholarly journals Plasmodium falciparum-Infected Erythrocytes and β-Hematin Induce Partial Maturation of Human Dendritic Cells and Increase Their Migratory Ability in Response to Lymphoid Chemokines

2011 ◽  
Vol 79 (7) ◽  
pp. 2727-2736 ◽  
Author(s):  
Pablo Giusti ◽  
Britta C. Urban ◽  
Giada Frascaroli ◽  
Letusa Albrecht ◽  
Anna Tinti ◽  
...  
Keyword(s):  
T Cells ◽  
Plasmodium Falciparum ◽  
Chemokine Receptors ◽  
Malaria Parasite ◽  
Human Monocyte ◽  
Synthetic Analog ◽  
Necrosis Factor Alpha ◽  
Content Type ◽  
And Migration ◽  
The Impact

ABSTRACTAcute and chronicPlasmodium falciparuminfections alter the immune competence of the host possibly through changes in dendritic cell (DC) functionality. DCs are the most potent activators of T cells, and migration is integral to their function. Mature DCs express lymphoid chemokine receptors (CCRs), expression of which enables them to migrate to the lymph nodes, where they encounter naïve T cells. The present study aimed to investigate the impact of the synthetic analog to malaria parasite pigment hemozoin, i.e., β-hematin, or infected erythrocytes (iRBCs) on the activation status of human monocyte-derived DCs and on their expression of CCRs. Human monocyte-derived DCs partially matured upon incubation with β-hematin as indicated by an increased expression of CD80 and CD83. Both β-hematin and iRBCs provoked the release of proinflammatory and anti-inflammatory cytokines, such as interleukin-6 (IL-6), IL-10, and tumor necrosis factor alpha, but not IL-12, and induced upregulation of the lymphoid chemokine receptor CXCR4, which was coupled to an increased migration to lymphoid ligands. Taken together, these results suggest that the partial and transient maturation of human myeloid DCs upon stimulation with malaria parasite-derived products and the increased IL-10 but lack of IL-12 secretion may lead to suboptimal activation of T cells. This may in turn lead to impaired adaptive immune responses and therefore insufficient clearance of the parasites.

scholarly journals Functional Characterization of the m6A-Dependent Translational Modulator PfYTH.2 in the Human Malaria Parasite

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Ameya Sinha ◽  
Sebastian Baumgarten ◽  
Amy Distiller ◽  
Emma McHugh ◽  
Patty Chen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Plasmodium Falciparum ◽  
Protein Synthesis ◽  
Malaria Parasite ◽  
Binding Proteins ◽  
Functional Characterization ◽  
Mrna Translation ◽  
Content Type ◽  
Mrna Transcripts

ABSTRACT Posttranscriptional regulation of gene expression is central to the development and replication of the malaria parasite, Plasmodium falciparum, within its human host. The timely coordination of RNA maturation, homeostasis, and protein synthesis relies on the recruitment of specific RNA-binding proteins to their cognate target mRNAs. One possible mediator of such mRNA-protein interactions is the N6-methylation of adenosines (m6A), a prevalent mRNA modification of parasite mRNA transcripts. Here, we used RNA protein pulldowns, RNA modification mass spectrometry, and quantitative proteomics to identify two P. falciparum YTH domain proteins (PfYTH.1 and PfYTH.2) as m6A-binding proteins during parasite blood-stage development. Interaction proteomics revealed that PfYTH.2 associates with the translation machinery, including multiple subunits of the eukaryotic initiation factor 3 (eIF3) and poly(A)-binding proteins. Furthermore, knock sideways of PfYTH.2 coupled with ribosome profiling showed that this m6A reader is essential for parasite survival and is a repressor of mRNA translation. Together, these data reveal an important missing link in the m6A-mediated mechanism controlling mRNA translation in a unicellular eukaryotic pathogen. IMPORTANCE Infection with the unicellular eukaryotic pathogen Plasmodium falciparum causes malaria, a mosquito-borne disease affecting more than 200 million and killing 400,000 people each year. Underlying the asexual replication within human red blood cells is a tight regulatory network of gene expression and protein synthesis. A widespread mechanism of posttranscriptional gene regulation is the chemical modification of adenosines (m6A), through which the fate of individual mRNA transcripts can be changed. Here, we report on the protein machinery that “reads” this modification and “translates” it into a functional outcome. We provide mechanistic insight into one m6A reader protein and show that it interacts with the translational machinery and acts as a repressor of mRNA translation. This m6A-mediated phenotype has not been described in other eukaryotes as yet, and the functional characterization of the m6A interactome will ultimately open new avenues to combat the disease.

scholarly journals Investigation of Heterochromatin Protein 1 Function in the Malaria Parasite Plasmodium falciparum Using a Conditional Domain Deletion and Swapping Approach

mSphere ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Hai T. N. Bui ◽  
Armin Passecker ◽  
Nicolas M. B. Brancucci ◽  
Till S. Voss
Keyword(s):  
Plasmodium Falciparum ◽  
Gene Silencing ◽  
Epigenetic Regulation ◽  
Malaria Parasite ◽  
Heterochromatin Protein 1 ◽  
Heterochromatin Protein ◽  
Content Type ◽  
Heterochromatin Formation ◽  
Parasite Multiplication ◽  
Hinge Domain

ABSTRACT The human malaria parasite Plasmodium falciparum encodes a single ortholog of heterochromatin protein 1 (PfHP1) that plays a crucial role in the epigenetic regulation of various survival-related processes. PfHP1 is essential for parasite proliferation and the heritable silencing of genes linked to antigenic variation, host cell invasion, and sexual conversion. Here, we employed CRISPR/Cas9-mediated genome editing combined with the DiCre/loxP system to investigate how the PfHP1 chromodomain (CD), hinge domain, and chromoshadow domain (CSD) contribute to overall PfHP1 function. We show that the 76 C-terminal residues are responsible for targeting PfHP1 to the nucleus. Furthermore, we reveal that each of the three functional domains of PfHP1 are required for heterochromatin formation, gene silencing, and mitotic parasite proliferation. Finally, we discovered that the hinge domain and CSD of HP1 are functionally conserved between P. falciparum and P. berghei, a related malaria parasite infecting rodents. In summary, our study provides new insights into PfHP1 function and offers a tool for further studies on epigenetic regulation and life cycle decision in malaria parasites. IMPORTANCE Malaria is caused by unicellular Plasmodium species parasites that repeatedly invade and replicate inside red blood cells. Some blood-stage parasites exit the cell cycle and differentiate into gametocytes that are essential for malaria transmission via the mosquito vector. Epigenetic control mechanisms allow the parasites to alter the expression of surface antigens and to balance the switch between parasite multiplication and gametocyte production. These processes are crucial to establish chronic infection and optimize parasite transmission. Here, we performed a mutational analysis of heterochromatin protein 1 (HP1) in P. falciparum. We demonstrate that all three domains of this protein are indispensable for the proper function of HP1 in parasite multiplication, heterochromatin formation, and gene silencing. Moreover, expression of chimeric proteins revealed the functional conservation of HP1 proteins between different Plasmodium species. These results provide new insight into the function and evolution of HP1 as an essential epigenetic regulator of parasite survival.

scholarly journals Adaptation of the [3H]Hypoxanthine Uptake Assay forIn Vitro-Cultured Plasmodium knowlesi Malaria Parasites

2016 ◽  
Vol 60 (7) ◽  
pp. 4361-4363 ◽  
Author(s):  
Megan S. J. Arnold ◽  
Jessica A. Engel ◽  
Ming Jang Chua ◽  
Gillian M. Fisher ◽  
Tina S. Skinner-Adams ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Drug Discovery ◽  
Malaria Parasite ◽  
Plasmodium Knowlesi ◽  
Malaria Parasites ◽  
Content Type ◽  
Zoonotic Malaria ◽  
Uptake Assay

ABSTRACTThe zoonotic malaria parasitePlasmodium knowlesihas recently been established in continuousin vitroculture. Here, thePlasmodium falciparum[3H]hypoxanthine uptake assay was adapted forP. knowlesiand used to determine the sensitivity of this parasite to chloroquine, cycloguanil, and clindamycin. The data demonstrate thatP. knowlesiis sensitive to all drugs, with 50% inhibitory concentrations (IC50s) consistent with those obtained withP. falciparum. This assay provides a platform to useP. knowlesi in vitrofor drug discovery.

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