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Diffendall G, Claes A, Barcons-Simon A, Nyarko P, Dingli F, Santos MM, Loew D, Claessens A, Scherf A. RNA polymerase III is involved in regulating Plasmodium falciparum virulence. eLife 2024; 13:RP95879. [PMID: 38921824 PMCID: PMC11208047 DOI: 10.7554/elife.95879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2024] Open
Abstract
While often undetected and untreated, persistent seasonal asymptomatic malaria infections remain a global public health problem. Despite the presence of parasites in the peripheral blood, no symptoms develop. Disease severity is correlated with the levels of infected red blood cells (iRBCs) adhering within blood vessels. Changes in iRBC adhesion capacity have been linked to seasonal asymptomatic malaria infections, however how this is occurring is still unknown. Here, we present evidence that RNA polymerase III (RNA Pol III) transcription in Plasmodium falciparum is downregulated in field isolates obtained from asymptomatic individuals during the dry season. Through experiments with in vitro cultured parasites, we have uncovered an RNA Pol III-dependent mechanism that controls pathogen proliferation and expression of a major virulence factor in response to external stimuli. Our findings establish a connection between P. falciparum cytoadhesion and a non-coding RNA family transcribed by Pol III. Additionally, we have identified P. falciparum Maf1 as a pivotal regulator of Pol III transcription, both for maintaining cellular homeostasis and for responding adaptively to external signals. These results introduce a novel perspective that contributes to our understanding of P. falciparum virulence. Furthermore, they establish a connection between this regulatory process and the occurrence of seasonal asymptomatic malaria infections.
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Affiliation(s)
- Gretchen Diffendall
- Institut Pasteur, Universite Paris CitéParisFrance
- Institut Pasteur, Sorbonne Université Ecole doctorale Complexité du VivantParisFrance
| | | | - Anna Barcons-Simon
- Institut Pasteur, Universite Paris CitéParisFrance
- Institut Pasteur, Sorbonne Université Ecole doctorale Complexité du VivantParisFrance
- Institut Pasteur, Biomedical Center, Division of Physiological Chemistry, Faculty of Medicine, Ludwig-Maximilians-Universität MünchenMunichGermany
| | - Prince Nyarko
- Institut Pasteur, Laboratory of Pathogen-Host Interaction (LPHI), CNRS, University of MontpellierMontpellierFrance
| | - Florent Dingli
- Institut Pasteur, Institut Curie, PSL Research University, Centre de Recherche, CurieCoreTech Mass Spectrometry ProteomicsParisFrance
| | - Miguel M Santos
- Institut Pasteur, Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de LisboaLisboaPortugal
| | - Damarys Loew
- Institut Pasteur, Institut Curie, PSL Research University, Centre de Recherche, CurieCoreTech Mass Spectrometry ProteomicsParisFrance
| | - Antoine Claessens
- Institut Pasteur, Laboratory of Pathogen-Host Interaction (LPHI), CNRS, University of MontpellierMontpellierFrance
- Institut Pasteur, LPHI, MIVEGEC, CNRS, INSERM, University of MontpellierMontpellierFrance
| | - Artur Scherf
- Institut Pasteur, Universite Paris CitéParisFrance
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Diffendall G, Scherf A. Deciphering the Plasmodium falciparum perinuclear var gene expression site. Trends Parasitol 2024:S1471-4922(24)00142-9. [PMID: 38910098 DOI: 10.1016/j.pt.2024.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 06/03/2024] [Accepted: 06/03/2024] [Indexed: 06/25/2024]
Abstract
The protozoan parasite Plasmodium falciparum, responsible for the deadliest form of human malaria, employs antigenic variation via monoallelic expression as a key survival strategy. The selective activation of one out of the 60-member var gene family is key to understanding the parasite's ability to cause severe disease and evade the host immune response. var gene activation is initiated by its relocation to a specialized expression site. While the perinuclear expression site (PES) plays a crucial role in enabling the expression of a single allele, the characteristics of this PES remain largely obscure. Recent breakthroughs in genome editing tools and the discovery of regulatory noncoding RNAs have shed light on this intriguing biological feature, offering significant insights into the mechanisms of pathogen virulence.
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Affiliation(s)
- Gretchen Diffendall
- Institut Pasteur, Universite Paris Cité, INSERM U1201, CNRS EMR9195, Paris, France
| | - Artur Scherf
- Institut Pasteur, Universite Paris Cité, INSERM U1201, CNRS EMR9195, Paris, France.
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Ewald S, Nasuhidehnavi A, Feng TY, Lesani M, McCall LI. The intersection of host in vivo metabolism and immune responses to infection with kinetoplastid and apicomplexan parasites. Microbiol Mol Biol Rev 2024; 88:e0016422. [PMID: 38299836 PMCID: PMC10966954 DOI: 10.1128/mmbr.00164-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024] Open
Abstract
SUMMARYProtozoan parasite infection dramatically alters host metabolism, driven by immunological demand and parasite manipulation strategies. Immunometabolic checkpoints are often exploited by kinetoplastid and protozoan parasites to establish chronic infection, which can significantly impair host metabolic homeostasis. The recent growth of tools to analyze metabolism is expanding our understanding of these questions. Here, we review and contrast host metabolic alterations that occur in vivo during infection with Leishmania, trypanosomes, Toxoplasma, Plasmodium, and Cryptosporidium. Although genetically divergent, there are commonalities among these pathogens in terms of metabolic needs, induction of the type I immune responses required for clearance, and the potential for sustained host metabolic dysbiosis. Comparing these pathogens provides an opportunity to explore how transmission strategy, nutritional demand, and host cell and tissue tropism drive similarities and unique aspects in host response and infection outcome and to design new strategies to treat disease.
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Affiliation(s)
- Sarah Ewald
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Azadeh Nasuhidehnavi
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
| | - Tzu-Yu Feng
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Mahbobeh Lesani
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Laura-Isobel McCall
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
- Laboratories of Molecular Anthropology and Microbiome Research, University of Oklahoma, Norman, Oklahoma, USA
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California, USA
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Leela N, Prommana P, Kamchonwongpaisan S, Taechalertpaisarn T, Shaw PJ. Antimalarial target vulnerability of the putative Plasmodium falciparum methionine synthase. PeerJ 2024; 12:e16595. [PMID: 38239295 PMCID: PMC10795524 DOI: 10.7717/peerj.16595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 11/14/2023] [Indexed: 01/22/2024] Open
Abstract
Background Plasmodium falciparum possesses a cobalamin-dependent methionine synthase (MS). MS is putatively encoded by the PF3D7_1233700 gene, which is orthologous and syntenic in Plasmodium. However, its vulnerability as an antimalarial target has not been assessed. Methods We edited the PF3D7_1233700 and PF3D7_0417200 (dihydrofolate reductase-thymidylate synthase, DHFR-TS) genes and obtained transgenic P. falciparum parasites expressing epitope-tagged target proteins under the control of the glmS ribozyme. Conditional loss-of-function mutants were obtained by treating transgenic parasites with glucosamine. Results DHFR-TS, but not MS mutants showed a significant proliferation defect over 96 h, suggesting that P. falciparum MS is not a vulnerable antimalarial target.
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Affiliation(s)
- Nirut Leela
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Bangkok, Thailand
| | - Parichat Prommana
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathum Thani, Thailand
| | - Sumalee Kamchonwongpaisan
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathum Thani, Thailand
| | - Tana Taechalertpaisarn
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Bangkok, Thailand
| | - Philip J. Shaw
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency, Pathum Thani, Thailand
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Stürmer VS, Stopper S, Binder P, Klemmer A, Lichti NP, Becker NB, Guizetti J. Progeny counter mechanism in malaria parasites is linked to extracellular resources. PLoS Pathog 2023; 19:e1011807. [PMID: 38051755 PMCID: PMC10723702 DOI: 10.1371/journal.ppat.1011807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 12/15/2023] [Accepted: 11/07/2023] [Indexed: 12/07/2023] Open
Abstract
Malaria is caused by the rapid proliferation of Plasmodium parasites in patients and disease severity correlates with the number of infected red blood cells in circulation. Parasite multiplication within red blood cells is called schizogony and occurs through an atypical multinucleated cell division mode. The mechanisms regulating the number of daughter cells produced by a single progenitor are poorly understood. We investigated underlying regulatory principles by quantifying nuclear multiplication dynamics in Plasmodium falciparum and knowlesi using super-resolution time-lapse microscopy. This confirmed that the number of daughter cells was consistent with a model in which a counter mechanism regulates multiplication yet incompatible with a timer mechanism. P. falciparum cell volume at the start of nuclear division correlated with the final number of daughter cells. As schizogony progressed, the nucleocytoplasmic volume ratio, which has been found to be constant in all eukaryotes characterized so far, increased significantly, possibly to accommodate the exponentially multiplying nuclei. Depleting nutrients by dilution of culture medium caused parasites to produce fewer merozoites and reduced proliferation but did not affect cell volume or total nuclear volume at the end of schizogony. Our findings suggest that the counter mechanism implicated in malaria parasite proliferation integrates extracellular resource status to modify progeny number during blood stage infection.
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Affiliation(s)
- Vanessa S. Stürmer
- Heidelberg University Medical Faculty, Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Sophie Stopper
- Heidelberg University Medical Faculty, Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Patrick Binder
- Institute for Theoretical Physics and BioQuant, Heidelberg University, Heidelberg, Germany
- Theoretical Systems Biology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Anja Klemmer
- Heidelberg University Medical Faculty, Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Nicolas P. Lichti
- Heidelberg University Medical Faculty, Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Nils B. Becker
- Theoretical Systems Biology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Julien Guizetti
- Heidelberg University Medical Faculty, Centre for Infectious Diseases, Heidelberg University Hospital, Heidelberg, Germany
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Piro F, Masci S, Kannan G, Focaia R, Schultz TL, Carruthers VB, Di Cristina M. A Toxoplasma gondii putative arginine transporter localizes to the plant-like vacuolar compartment and controls parasite extracellular survival and stage differentiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.31.555807. [PMID: 37693549 PMCID: PMC10491228 DOI: 10.1101/2023.08.31.555807] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Toxoplasma gondii is a protozoan parasite that infects a broad spectrum of hosts and can colonize many organs and cell types. The ability to reside within a wide range of different niches requires substantial adaptability to diverse microenvironments. Very little is known about how this parasite senses various milieus and adapts its metabolism to survive, replicate during the acute stage, and then differentiate to the chronic stage. Most eukaryotes, from yeast to mammals, rely on a nutrient sensing machinery involving the TORC complex as master regulator of cell growth and cell cycle progression. The lysosome functions as a signaling hub where TORC complex assembles and is activated by transceptors, which both sense and transport amino acids, including the arginine transceptor SLC38A9. While most of the TORC components are lost in T. gondii , indicating the evolution of a distinct nutrient sensing mechanism, the parasite's lysosomal plant-like vacuolar compartment (PLVAC) may still serve as a sensory platform for controlling parasite growth and differentiation. Using SLC38A9 to query the T. gondii proteome, we identified four putative amino acid transporters, termed TgAAT1-4, that structurally resemble the SLC38A9 arginine transceptor. Assessing their expression and sub-cellular localization, we found that one of them, TgAAT1, localized to the PLVAC and is necessary for normal parasite extracellular survival and bradyzoite differentiation. Moreover, we show that TgAAT1 is involved in the PLVAC efflux of arginine, an amino acid playing a key role in T. gondii differentiation, further supporting the hypothesis that TgAAT1 might play a role in nutrient sensing. IMPORTANCE T. gondii is a highly successful parasite infecting a broad range of warm-blood organisms including about one third of all humans. Although Toxoplasma infections rarely result in symptomatic disease in individuals with a healthy immune system, the incredibly high number of persons infected along with the risk of severe infection in immunocompromised patients and the potential link of chronic infection to mental disorders make this infection a significant public health concern. As a result, there is a pressing need for new treatment approaches that are both effective and well-tolerated. The limitations in understanding how Toxoplasma gondii manages its metabolism to adapt to changing environments and triggers its transformation into bradyzoites have hindered the discovery of vulnerabilities in its metabolic pathways or nutrient acquisition mechanisms to identify new therapeutic targets. In this work, we have shown that the lysosome-like organelle PLVAC, acting through the putative arginine transporter TgAAT1, plays a pivotal role in regulating the parasite's extracellular survival and differentiation into bradyzoites.
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