The Transcription Factor PfAP2-O Influences Virulence Gene Transcription and Sexual Development in Plasmodium falciparum

The human malaria parasite Plasmodium falciparum expresses variant PfEMP1 proteins on the infected erythrocyte, which function as ligands for endothelial receptors in capillary vessels, leading to erythrocyte sequestration and severe malaria. The factors that orchestrate the mono-allelic expression of the 45–90 PfEMP1-encoding var genes within each parasite genome are still not fully identified. Here, we show that the transcription factor PfAP2-O influences the transcription of var genes. The temporary knockdown of PfAP2-O leads to a complete loss of var transcriptional memory and a decrease in cytoadherence in CD36 adherent parasites. AP2-O-knocked-down parasites exhibited also significant reductions in transmission through Anopheles mosquitoes. We propose that PfAP2-O is, beside its role in transmission stages, also one of the virulence gene transcriptional regulators and may therefore be exploited as an important target to disrupt severe malaria and block parasite transmission.

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An ApiAP2 transcription factor influencing virulence gene transcription and sexual development in Plasmodium falciparum

10.21203/rs.3.rs-48641/v1 ◽

2020 ◽

Author(s):

Eliana Cubillos ◽

Isadora Prata ◽

Wesley Fotoran ◽

Nicolas Cardenas ◽

Diego Alonso ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Transcription Factor ◽

Severe Malaria ◽

Virulence Gene ◽

Human Malaria Parasite ◽

Var Genes ◽

Anopheles Mosquitoes ◽

Parasite Plasmodium ◽

Parasite Plasmodium Falciparum ◽

Transcriptional Memory

Abstract The human malaria parasite Plasmodium falciparum expresses variant PfEMP1 proteins on the infected erythrocyte, which function as ligands for endothelial receptors in capillary vessels, leading to erythrocyte sequestration and severe malaria. The factors that orchestrate the mono-allelic expression of the 50-60 PfEMP1-encoding var genes within each parasite genome are still not fully identified. Here, we show that the transcription factor PfAP2-O influences the transcription of var genes and other multigenic families. The temporary knockdown of PfAP2-O leads to a complete loss of var transcriptional memory and a decrease in cytoadherence. AP2-O-knocked down parasites exhibited also significant reductions in transmission through Anopheles mosquitoes. We propose that PfAP2-O is one of the major virulence gene transcriptional regulators and may, therefore, be exploited as an important target to disrupt severe malaria and block parasite transmission.

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Conditional expression of PfAP2-G for controlled massive sexual conversion in Plasmodium falciparum

Science Advances ◽

10.1126/sciadv.aaz5057 ◽

2020 ◽

Vol 6 (24) ◽

pp. eaaz5057 ◽

Cited By ~ 7

Author(s):

Oriol Llorà-Batlle ◽

Lucas Michel-Todó ◽

Kathrin Witmer ◽

Haruka Toda ◽

Carmen Fernández-Becerra ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Transcription Factor ◽

Sexual Development ◽

Malaria Parasite ◽

Drug Susceptibility ◽

Small Subset ◽

Human Malaria Parasite ◽

Conditional Expression ◽

Sexual Stages

Malaria transmission requires that some asexual parasites convert into sexual forms termed gametocytes. The initial stages of sexual development, including sexually committed schizonts and sexual rings, remain poorly characterized, mainly because they are morphologically identical to their asexual counterparts and only a small subset of parasites undergo sexual development. Here, we describe a system for controlled sexual conversion in the human malaria parasite Plasmodium falciparum, based on conditional expression of the PfAP2-G transcription factor. Using this system, ~90 percent of the parasites converted into sexual forms upon induction, enabling the characterization of committed and early sexual stages without further purification. We characterized sexually committed schizonts and sexual rings at the transcriptomic and phenotypic levels, which revealed down-regulation of genes involved in solute transport upon sexual commitment, among other findings. The new inducible lines will facilitate the study of early sexual stages at additional levels, including multiomic characterization and drug susceptibility assays.

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Antibody Recognition of Plasmodium falciparum Erythrocyte Surface Antigens in Kenya: Evidence for Rare and Prevalent Variants

Infection and Immunity ◽

10.1128/iai.67.2.733-739.1999 ◽

1999 ◽

Vol 67 (2) ◽

pp. 733-739 ◽

Cited By ~ 120

Author(s):

Peter C. Bull ◽

Brett S. Lowe ◽

Moses Kortok ◽

Kevin Marsh

Keyword(s):

Plasmodium Falciparum ◽

Severe Malaria ◽

Inverse Relationship ◽

Infected Erythrocyte ◽

Surface Antigens ◽

Maternal Antibodies ◽

Antibody Repertoire ◽

Parasite Isolate ◽

Antibody Recognition ◽

Erythrocyte Surface

ABSTRACT Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is the name given to a family of parasite proteins that are inserted into the infected erythrocyte surface. Studies using agglutination assays have shown previously that PfEMP1 epitopes are extremely diverse. In a study in Kenya, 21 parasite isolates, including nine from children with severe malaria, were tested for agglutination by 33 pairs of plasma, 21 of which were from the corresponding children. Each plasma pair consisted of a sample taken at the time of disease (acute) and one taken 3 weeks later (convalescent). In agreement with previous studies, infection was generally followed by the induction of antibodies specific to the homologous parasite isolate. In addition however, the results show that (i) some isolates were agglutinated very frequently by heterologous plasma; (ii) unexpectedly, these frequently agglutinated isolates tended to be from individuals with severe malaria; (iii) an inverse relationship existed between the agglutination frequency of each parasite isolate in heterologous plasma and the agglutinating antibody repertoire of the homologous child at the time of disease; and (iv) A 3-month-old child apparently still carrying maternal antibodies was infected by a rarely agglutinated isolate. This child’s plasma agglutinated all isolates at the time of disease, apart from the homologous isolate. These results support the idea that preexisting anti-PfEMP1 antibodies can select the variants that are expressed during a new infection and may suggest the existence of a dominant subset of PfEMP1 variants.

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Genome-wide analysis of the human malaria parasite Plasmodium falciparum transcription factor PfNF-YB shows interaction with a CCAAT motif

Oncotarget ◽

10.18632/oncotarget.23053 ◽

2017 ◽

Vol 8 (69) ◽

pp. 113987-114001 ◽

Cited By ~ 1

Author(s):

Wânia Rezende Lima ◽

David Correa Martins ◽

Kleber Simônio Parreira ◽

Pedro Scarpelli ◽

Miriam Santos de Moraes ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Transcription Factor ◽

Malaria Parasite ◽

Human Malaria Parasite ◽

Genome Wide Analysis ◽

Human Malaria ◽

Genome Wide ◽

Parasite Plasmodium ◽

Parasite Plasmodium Falciparum

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Plasmodium falciparum STEVOR phosphorylation regulates host erythrocyte deformability enabling malaria parasite transmission

Blood ◽

10.1182/blood-2016-01-690776 ◽

2016 ◽

Vol 127 (24) ◽

pp. e42-e53 ◽

Cited By ~ 25

Author(s):

Bernina Naissant ◽

Florian Dupuy ◽

Yoann Duffier ◽

Audrey Lorthiois ◽

Julien Duez ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Malaria Parasite ◽

Infected Erythrocyte ◽

Cytoplasmic Domain ◽

Erythrocyte Deformability ◽

Parasite Transmission ◽

Key Points

Key Points P falciparum STEVORs interact with the erythrocyte cytoskeletal ankyrin complex. Infected erythrocyte deformability is regulated by PKA-mediated phosphorylation of STEVOR cytoplasmic domain.

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Inhibition of protein N-myristoylation blocks Plasmodium falciparum intraerythrocytic development, egress and invasion

PLoS Biology ◽

10.1371/journal.pbio.3001408 ◽

2021 ◽

Vol 19 (10) ◽

pp. e3001408

Author(s):

Anja C. Schlott ◽

Ellen Knuepfer ◽

Judith L. Green ◽

Philip Hobson ◽

Aaron J. Borg ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Infected Erythrocyte ◽

Complex Function ◽

Pleiotropic Effect ◽

Substantial Effect ◽

Parasite Development ◽

Human Malaria Parasite ◽

Erythrocyte Invasion ◽

Erythrocytic Cycle ◽

Parasite Egress

We have combined chemical biology and genetic modification approaches to investigate the importance of protein myristoylation in the human malaria parasite, Plasmodium falciparum. Parasite treatment during schizogony in the last 10 to 15 hours of the erythrocytic cycle with IMP-1002, an inhibitor of N-myristoyl transferase (NMT), led to a significant blockade in parasite egress from the infected erythrocyte. Two rhoptry proteins were mislocalized in the cell, suggesting that rhoptry function is disrupted. We identified 16 NMT substrates for which myristoylation was significantly reduced by NMT inhibitor (NMTi) treatment, and, of these, 6 proteins were substantially reduced in abundance. In a viability screen, we showed that for 4 of these proteins replacement of the N-terminal glycine with alanine to prevent myristoylation had a substantial effect on parasite fitness. In detailed studies of one NMT substrate, glideosome-associated protein 45 (GAP45), loss of myristoylation had no impact on protein location or glideosome assembly, in contrast to the disruption caused by GAP45 gene deletion, but GAP45 myristoylation was essential for erythrocyte invasion. Therefore, there are at least 3 mechanisms by which inhibition of NMT can disrupt parasite development and growth: early in parasite development, leading to the inhibition of schizogony and formation of “pseudoschizonts,” which has been described previously; at the end of schizogony, with disruption of rhoptry formation, merozoite development and egress from the infected erythrocyte; and at invasion, when impairment of motor complex function prevents invasion of new erythrocytes. These results underline the importance of P. falciparum NMT as a drug target because of the pleiotropic effect of its inhibition.

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A switch in infected erythrocyte deformability at the maturation and blood circulation of Plasmodium falciparum transmission stages

Blood ◽

10.1182/blood-2012-03-414557 ◽

2012 ◽

Vol 119 (24) ◽

pp. e172-e180 ◽

Cited By ~ 86

Author(s):

Marta Tibúrcio ◽

Makhtar Niang ◽

Guillaume Deplaine ◽

Sylvie Perrot ◽

Emmanuel Bischoff ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Blood Circulation ◽

Infected Erythrocyte ◽

Erythrocyte Deformability ◽

Mature Stage ◽

Parasite Transmission ◽

Immature Stages ◽

Sexual Stages ◽

Cellular Deformability ◽

Host Tissues

AbstractAchievement of malaria elimination requires development of novel strategies interfering with parasite transmission, including targeting the parasite sexual stages (gametocytes). The formation of Plasmodium falciparum gametocytes in the human host takes several days during which immature gametocyte-infected erythrocytes (GIEs) sequester in host tissues. Only mature stage GIEs circulate in the peripheral blood, available to uptake by the Anopheles vector. Mechanisms underlying GIE sequestration and release in circulation are virtually unknown. We show here that mature GIEs are more deformable than immature stages using ektacytometry and microsphiltration methods, and that a switch in cellular deformability in the transition from immature to mature gametocytes is accompanied by the deassociation of parasite-derived STEVOR proteins from the infected erythrocyte membrane. We hypothesize that mechanical retention contributes to sequestration of immature GIEs and that regained deformability of mature gametocytes is associated with their release in the bloodstream and ability to circulate. These processes are proposed to play a key role in P falciparum gametocyte development in the host and to represent novel and unconventional targets for interfering with parasite transmission.

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Inhibition of protein N-myristoylation blocks Plasmodium falciparum intraerythrocytic development, egress, and invasion

10.1101/2020.12.16.423054 ◽

2020 ◽

Author(s):

Anja C. Schlott ◽

Ellen Knuepfer ◽

Judith L. Green ◽

Philip Hobson ◽

Aaron J. Borg ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Infected Erythrocyte ◽

Complex Function ◽

Pleiotropic Effect ◽

Substantial Effect ◽

Parasite Development ◽

Human Malaria Parasite ◽

Erythrocyte Invasion ◽

Erythrocytic Cycle ◽

Parasite Egress

ABSTRACTWe have combined chemical biology and genetic modification approaches to investigate the importance of protein myristoylation in the human malaria parasite, Plasmodium falciparum. Parasite treatment during schizogony in the last ten to fifteen hours of the erythrocytic cycle with IMP-1002, an inhibitor of N-myristoyl transferase (NMT), led to a significant blockade in parasite egress from the infected erythrocyte. Two rhoptry proteins were mislocalized in the cell, suggesting that rhoptry function is disrupted. We identified sixteen NMT substrates for which myristoylation was significantly reduced by NMT inhibitor treatment, and of these, six proteins were substantially reduced in abundance. In a viability screen, we showed that for four of these proteins replacement of the N-terminal glycine with alanine to prevent myristoylation had a substantial effect on parasite fitness. In detailed studies of one NMT substrate, glideosome associated protein 45 (GAP45), loss of myristoylation had no impact on protein location or glideosome assembly, in contrast to the disruption caused by GAP45 gene deletion, but GAP45 myristoylation was essential for erythrocyte invasion. Therefore, there are at least three mechanisms by which inhibition of NMT can disrupt parasite development and growth: early in parasite development, leading to the inhibition of schizogony and formation of ‘pseudoschizonts’, which has been described previously; at the end of schizogony, with disruption of rhoptry formation, merozoite development and egress from the infected erythrocyte; and at invasion, when impairment of motor complex function prevents invasion of new erythrocytes. These results underline the importance of P. falciparum NMT as a drug target because of the pleiotropic effect of its inhibition.

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