The asexual forms of the malaria parasite Plasmodium falciparum are adapted for chronic persistence in human red blood cells, continuously evading host immunity using epigenetically regulated antigenic variation of virulence-associated genes. Parasite survival on a population level also requires differentiation into sexual forms, an obligatory step for further human transmission. We reveal that the essential nuclear gene, P. falciparum histone deacetylase 2 (PfHda2), is a global silencer of virulence gene expression and controls the frequency of switching from the asexual cycle to sexual development. PfHda2 depletion leads to dysregulated expression of both virulence-associated var genes and PfAP2-g, a transcription factor controlling sexual conversion, and is accompanied by increases in gametocytogenesis. Mathematical modeling further indicates that PfHda2 has likely evolved to optimize the parasite's infectious period by achieving low frequencies of virulence gene expression switching and sexual conversion. This common regulation of cellular transcriptional programs mechanistically links parasite transmissibility and virulence.
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http://dx.doi.org/10.1016/j.chom.2014.06.014 | DOI Listing |
Sci Rep
January 2025
Department of Evolutionary Anthropology, University of Vienna, Vienna, Austria.
Malaria has been a leading cause of death in human populations for centuries and remains a major public health challenge in African countries, especially affecting children. Among the five Plasmodium species infecting humans, Plasmodium falciparum is the most lethal. Ancient DNA research has provided key insights into the origins, evolution, and virulence of pathogens that affect humans.
View Article and Find Full Text PDFTrends Parasitol
January 2025
Department of Infectious Diseases, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne 3000, Australia; Department of Microbiology and Immunology, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Melbourne 3000, Australia.
In Plasmodium falciparum malaria, infected cells accumulate in blood vessels of organs, including the brain. Recently, Reyes et al. identified monoclonal antibodies that stop infected cells from binding to the endothelial protein C receptor (EPCR) in a model of brain blood vessels.
View Article and Find Full Text PDFNat Med
January 2025
Leiden University Center for Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands.
Malaria vaccines consisting of metabolically active Plasmodium falciparum (Pf) sporozoites can offer improved protection compared with currently deployed subunit vaccines. In a previous study, we demonstrated the superior protective efficacy of a three-dose regimen of late-arresting genetically attenuated parasites administered by mosquito bite (GA2-MB) compared with early-arresting counterparts (GA1-MB) against a homologous controlled human malaria infection. Encouraged by these results, we explored the potency of a single GA2-MB immunization in a placebo-controlled randomized trial.
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January 2025
Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou (IRR), Fundação Oswaldo Cruz (FIOCRUZ), Minas Gerais, Brazil.
Rapid Diagnostic Tests (RDTs) have been an important diagnostic tool for detecting P. falciparum malaria in resource-limited settings. Most tests are designed to detect the Histidine-rich Protein 2 (HRP2).
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January 2025
Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel St, London, WC1E 7HT, UK.
The significance of multiplication rate variation in malaria parasites needs to be determined, particularly for Plasmodium falciparum, the species that causes most virulent infections. To investigate this, parasites from cases presenting to hospital in The Gambia and from local community infections were culture-established and then tested under exponential growth conditions in a standardised six-day multiplication rate assay. The multiplication rate distribution was lower than seen previously in clinical isolates from another area in West Africa where infection is more highly endemic.
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