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Serra L, Silva Pereira S, Viegas IJ, Machado H, López-Escobar L, Figueiredo LM. m 6A landscape is more pervasive when Trypanosoma brucei exits the cell cycle. Biomed J 2024:100728. [PMID: 38641210 DOI: 10.1016/j.bj.2024.100728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/11/2024] [Accepted: 04/11/2024] [Indexed: 04/21/2024] Open
Abstract
N6-methyladenosine (m6A) is a mRNA modification with important roles in gene expression. In African trypanosomes, this post-transcriptional modification is detected in hundreds of transcripts and it affects the stability of the variant surface glycoprotein (VSG) transcript in the proliferating blood stream form. However, how the m6A landscape varies across the life cycle remains poorly defined. Using full-length, non-fragmented RNA, we immunoprecipitated and sequenced m6A-modified transcripts across three life cycle stages of Trypanosoma brucei - slender (proliferative), stumpy (quiescent), and procyclic forms (proliferative). We found that 1037 transcripts are methylated in at least one of these three life cycle stages. While 21% of methylated transcripts are common in the three stages of the life cycle, globally each stage has a distinct methylome. Interestingly, 47% of methylated transcripts are detected in the quiescent stumpy form only, suggesting a critical role for m6A when parasites exit the cell cycle and prepare for transmission by the Tsetse fly. In this stage, we found that a significant proportion of methylated transcripts encodes for proteins involved in RNA metabolism, which is consistent with their reduced transcription and translation. Moreover, we found that not all major surface proteins are regulated by m6A, as procyclins are not methylated, and that, within the VSG repertoire, not all VSG transcripts are demethylated upon parasite differentiation to procyclic form. This study reveals that the m6A regulatory landscape is specific to each life cycle stage, becoming more pervasive as T. brucei exits the cell cycle.
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Affiliation(s)
- Lúcia Serra
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa
| | - Sara Silva Pereira
- Católica Biomedical Research Centre, Católica Medical School, Universidade Católica Portuguesa
| | - Idálio J Viegas
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa; Current affiliation: Institute of Inflammation and Ageing, University of Birmingham
| | - Henrique Machado
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa
| | - Lara López-Escobar
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa.
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2
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Guegan F, Rajan KS, Bento F, Pinto-Neves D, Sequeira M, Gumińska N, Mroczek S, Dziembowski A, Cohen-Chalamish S, Doniger T, Galili B, Estévez AM, Notredame C, Michaeli S, Figueiredo LM. A long noncoding RNA promotes parasite differentiation in African trypanosomes. Sci Adv 2022; 8:eabn2706. [PMID: 35704590 PMCID: PMC9200285 DOI: 10.1126/sciadv.abn2706] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The parasite Trypanosoma brucei causes African sleeping sickness that is fatal to patients if untreated. Parasite differentiation from a replicative slender form into a quiescent stumpy form promotes host survival and parasite transmission. Long noncoding RNAs (lncRNAs) are known to regulate cell differentiation in other eukaryotes. To determine whether lncRNAs are also involved in parasite differentiation, we used RNA sequencing to survey the T. brucei genome, identifying 1428 previously uncharacterized lncRNA genes. We find that grumpy lncRNA is a key regulator that promotes parasite differentiation into the quiescent stumpy form. This function is promoted by a small nucleolar RNA encoded within the grumpy lncRNA. snoGRUMPY binds to messenger RNAs of at least two stumpy regulatory genes, promoting their expression. grumpy overexpression reduces parasitemia in infected mice. Our analyses suggest that T. brucei lncRNAs modulate parasite-host interactions and provide a mechanism by which grumpy regulates cell differentiation in trypanosomes.
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Affiliation(s)
- Fabien Guegan
- Instituto de Medicina Molecular–Joao Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- Corresponding author. (F.G.); (L.M.F.)
| | - K. Shanmugha Rajan
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Fábio Bento
- Instituto de Medicina Molecular–Joao Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Daniel Pinto-Neves
- Instituto de Medicina Molecular–Joao Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Mariana Sequeira
- Instituto de Medicina Molecular–Joao Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Natalia Gumińska
- Laboratory of RNA Biology, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Seweryn Mroczek
- Laboratory of RNA Biology, International Institute of Molecular and Cell Biology, Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Andrzej Dziembowski
- Laboratory of RNA Biology, International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Smadar Cohen-Chalamish
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Tirza Doniger
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Beathrice Galili
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Antonio M. Estévez
- Instituto de Parasitologia y Biomedicina ‘Lopez-Neyra,’ IPBLN-CSIC, Parque Tecnológico de Ciencias de la Salud, Avda. del Conocimiento 17, 18016 Armilla, Granada, Spain
| | - Cedric Notredame
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Shulamit Michaeli
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Luisa M. Figueiredo
- Instituto de Medicina Molecular–Joao Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- Corresponding author. (F.G.); (L.M.F.)
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3
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De Niz M, Figueiredo LM. Surgical and intravital microscopy protocol to image Trypanosoma brucei–host interactions in live rodent models. STAR Protoc 2022; 3:101450. [PMID: 35719266 PMCID: PMC9201065 DOI: 10.1016/j.xpro.2022.101450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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4
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Viegas IJ, Figueiredo LM. From trans-splicing discovery and onwards, trypanosomes lead the way. Nat Rev Mol Cell Biol 2022; 23:388. [PMID: 35444303 DOI: 10.1038/s41580-022-00489-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Idálio J Viegas
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.
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5
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Viegas IJ, de Macedo JP, Serra L, De Niz M, Temporão A, Silva Pereira S, Mirza AH, Bergstrom E, Rodrigues JA, Aresta-Branco F, Jaffrey SR, Figueiredo LM. N 6-methyladenosine in poly(A) tails stabilize VSG transcripts. Nature 2022; 604:362-370. [PMID: 35355019 DOI: 10.1038/s41586-022-04544-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 02/10/2022] [Indexed: 12/24/2022]
Abstract
RNA modifications are important regulators of gene expression1. In Trypanosoma brucei, transcription is polycistronic and thus most regulation happens post-transcriptionally2. N6-methyladenosine (m6A) has been detected in this parasite, but its function remains unknown3. Here we found that m6A is enriched in 342 transcripts using RNA immunoprecipitation, with an enrichment in transcripts encoding variant surface glycoproteins (VSGs). Approximately 50% of the m6A is located in the poly(A) tail of the actively expressed VSG transcripts. m6A residues are removed from the VSG poly(A) tail before deadenylation and mRNA degradation. Computational analysis revealed an association between m6A in the poly(A) tail and a 16-mer motif in the 3' untranslated region of VSG genes. Using genetic tools, we show that the 16-mer motif acts as a cis-acting motif that is required for inclusion of m6A in the poly(A) tail. Removal of this motif from the 3' untranslated region of VSG genes results in poly(A) tails lacking m6A, rapid deadenylation and mRNA degradation. To our knowledge, this is the first identification of an RNA modification in the poly(A) tail of any eukaryote, uncovering a post-transcriptional mechanism of gene regulation.
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Affiliation(s)
- Idálio J Viegas
- Instituto de Medicina Molecular-João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Juan Pereira de Macedo
- Instituto de Medicina Molecular-João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Lúcia Serra
- Instituto de Medicina Molecular-João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Mariana De Niz
- Instituto de Medicina Molecular-João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Adriana Temporão
- Instituto de Medicina Molecular-João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Sara Silva Pereira
- Instituto de Medicina Molecular-João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Aashiq H Mirza
- Department of Pharmacology, Weill Medical College, Cornell University, New York, NY, USA
| | - Ed Bergstrom
- Department of Chemistry, University of York, York, UK.,Centre of Excellence in Mass Spectrometry, University of York, York, UK
| | - João A Rodrigues
- Instituto de Medicina Molecular-João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.,Clarify Analytical, Évora, Portugal
| | - Francisco Aresta-Branco
- Instituto de Medicina Molecular-João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.,Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany.,Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Samie R Jaffrey
- Department of Pharmacology, Weill Medical College, Cornell University, New York, NY, USA
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular-João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.
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Temporão A, Sanches-Vaz M, Luís R, Nunes-Cabaço H, Smith TK, Prudêncio M, Figueiredo LM. Excreted Trypanosoma brucei proteins inhibit Plasmodium hepatic infection. PLoS Negl Trop Dis 2021; 15:e0009912. [PMID: 34714824 PMCID: PMC8580256 DOI: 10.1371/journal.pntd.0009912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 11/10/2021] [Accepted: 10/15/2021] [Indexed: 11/25/2022] Open
Abstract
Malaria, a disease caused by Plasmodium parasites, remains a major threat to public health globally. It is the most common disease in patients with sleeping sickness, another parasitic illness, caused by Trypanosoma brucei. We have previously shown that a T. brucei infection impairs a secondary P. berghei liver infection and decreases malaria severity in mice. However, whether this effect requires an active trypanosome infection remained unknown. Here, we show that Plasmodium liver infection can also be inhibited by the serum of a mouse previously infected by T. brucei and by total protein lysates of this kinetoplastid. Biochemical characterisation showed that the anti-Plasmodium activity of the total T. brucei lysates depends on its protein fraction, but is independent of the abundant variant surface glycoprotein. Finally, we found that the protein(s) responsible for the inhibition of Plasmodium infection is/are present within a fraction of ~350 proteins that are excreted to the bloodstream of the host. We conclude that the defence mechanism developed by trypanosomes against Plasmodium relies on protein excretion. This study opens the door to the identification of novel antiplasmodial intervention strategies.
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Affiliation(s)
- Adriana Temporão
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Margarida Sanches-Vaz
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Rafael Luís
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Helena Nunes-Cabaço
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Terry K. Smith
- Schools of Biology and Chemistry Biomedical Sciences Research Complex, The North Haugh, The University, St. Andrews, Scotland, United Kingdom
| | - Miguel Prudêncio
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Luisa M. Figueiredo
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
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7
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De Niz M, Brás D, Ouarné M, Pedro M, Nascimento AM, Henao Misikova L, Franco CA, Figueiredo LM. Organotypic endothelial adhesion molecules are key for Trypanosoma brucei tropism and virulence. Cell Rep 2021; 36:109741. [PMID: 34551286 PMCID: PMC8480282 DOI: 10.1016/j.celrep.2021.109741] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 06/29/2021] [Accepted: 08/28/2021] [Indexed: 11/23/2022] Open
Abstract
Trypanosoma brucei is responsible for lethal diseases in humans and cattle in Sub-Saharan Africa. These extracellular parasites extravasate from the blood circulation into several tissues. The importance of the vasculature in tissue tropism is poorly understood. Using intravital imaging and bioluminescence, we observe that gonadal white adipose tissue and pancreas are the two main parasite reservoirs. We show that reservoir establishment happens before vascular permeability is compromised, suggesting that extravasation is an active mechanism. Blocking endothelial surface adhesion molecules (E-selectin, P-selectins, or ICAM2) significantly reduces extravascular parasite density in all organs and delays host lethality. Remarkably, blocking CD36 has a specific effect on adipose tissue tropism that is sufficient to delay lethality, suggesting that establishment of the adipose tissue reservoir is necessary for parasite virulence. This work demonstrates the importance of the vasculature in a T. brucei infection and identifies organ-specific adhesion molecules as key players for tissue tropism. Our study investigates the blood vasculature for T. brucei reservoir establishment We show the pancreas is a large extravascular reservoir We establish that T. brucei tropism is linked to organotypic adhesion molecules Interfering with adhesion molecules impacts parasite virulence and host survival
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Affiliation(s)
- Mariana De Niz
- Instituto de Medicina Molecular Joao Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Daniela Brás
- Instituto de Medicina Molecular Joao Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Marie Ouarné
- Instituto de Medicina Molecular Joao Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Mafalda Pedro
- Instituto de Medicina Molecular Joao Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal; Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica 2825-149, Portugal
| | - Ana M Nascimento
- Instituto de Medicina Molecular Joao Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal; Bioimaging Unit, Instituto de Medicina Molecular Joao Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Lenka Henao Misikova
- Instituto de Medicina Molecular Joao Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Claudio A Franco
- Instituto de Medicina Molecular Joao Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular Joao Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal.
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8
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Machado H, Bizarra-Rebelo T, Costa-Sequeira M, Trindade S, Carvalho T, Rijo-Ferreira F, Rentroia-Pacheco B, Serre K, Figueiredo LM. Trypanosoma brucei triggers a broad immune response in the adipose tissue. PLoS Pathog 2021; 17:e1009933. [PMID: 34525131 PMCID: PMC8476018 DOI: 10.1371/journal.ppat.1009933] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 09/27/2021] [Accepted: 08/31/2021] [Indexed: 12/13/2022] Open
Abstract
Adipose tissue is one of the major reservoirs of Trypanosoma brucei parasites, the causative agent of sleeping sickness, a fatal disease in humans. In mice, the gonadal adipose tissue (AT) typically harbors 2–5 million parasites, while most solid organs show 10 to 100-fold fewer parasites. In this study, we tested whether the AT environment responds immunologically to the presence of the parasite. Transcriptome analysis of T. brucei infected adipose tissue revealed that most upregulated host genes are involved in inflammation and immune cell functions. Histochemistry and flow cytometry confirmed an increasingly higher number of infiltrated macrophages, neutrophils and CD4+ and CD8+ T lymphocytes upon infection. A large proportion of these lymphocytes effectively produce the type 1 effector cytokines, IFN-γ and TNF-α. Additionally, the adipose tissue showed accumulation of antigen-specific IgM and IgG antibodies as infection progressed. Mice lacking T and/or B cells (Rag2-/-, Jht-/-), or the signature cytokine (Ifng-/-) displayed a higher parasite load both in circulation and in the AT, demonstrating the key role of the adaptive immune system in both compartments. Interestingly, infections of C3-/- mice showed that while complement system is dispensable to control parasite load in the blood, it is necessary in the AT and other solid tissues. We conclude that T. brucei infection triggers a broad and robust immune response in the AT, which requires the complement system to locally reduce parasite burden. African trypanosomiasis is a neglected disease with significant socio-economic burden in sub-Saharan Africa. The protozoan parasite Trypanosoma brucei, a causative agent of African trypanosomiasis, can be found in the blood and extra-vascular spaces of the infected host. For an unknown reason, T. brucei accumulates in adipose tissue (AT) in very high numbers. Here we used a multidisciplinary approach to assess whether an immune response was mounted in AT during a T. brucei infection. We found that as infection progresses, a broad variety of immune cells and antibodies accumulate in the AT. We also found that this broad immune response is partially able to control parasite numbers in the AT. Our study provides evidence that T. brucei parasites present in the AT are subjected to immune surveillance. The reason why T. brucei accumulates to such a high extent in AT remains to be elucidated.
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Affiliation(s)
- Henrique Machado
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Tiago Bizarra-Rebelo
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Mariana Costa-Sequeira
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Sandra Trindade
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Tânia Carvalho
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Filipa Rijo-Ferreira
- Department of Neuroscience, Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Barbara Rentroia-Pacheco
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Karine Serre
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- * E-mail: (KS); (LMF)
| | - Luisa M. Figueiredo
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- * E-mail: (KS); (LMF)
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9
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Abstract
Recent developments in single-cell and single-molecule techniques have revealed surprising levels of heterogeneity among isogenic cells. These advances have transformed the study of cell-to-cell heterogeneity into a major area of biomedical research, revealing that it can confer essential advantages, such as priming populations of unicellular organisms for future environmental stresses. Protozoan parasites, such as trypanosomes, face multiple and often hostile environments, and to survive, they undergo multiple changes, including changes in morphology, gene expression, and metabolism. But why does only a subset of proliferative cells differentiate to the next life cycle stage? Why do only some bloodstream parasites undergo antigenic switching while others stably express one variant surface glycoprotein? And why do some parasites invade an organ while others remain in the bloodstream? Building on extensive research performed in bacteria, here we suggest that biological noise can contribute to the fitness of eukaryotic pathogens and discuss the importance of cell-to-cell heterogeneity in trypanosome infections. Expected final online publication date for the Annual Review of Microbiology, Volume 75 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Vanessa Luzak
- Division of Experimental Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich 82152, Germany.,Biomedical Center, Division of Physiological Chemistry, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich 82152, Germany
| | - Lara López-Escobar
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal;
| | - T Nicolai Siegel
- Division of Experimental Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich 82152, Germany.,Biomedical Center, Division of Physiological Chemistry, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich 82152, Germany
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal;
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10
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Abstract
Parasitic diseases, such as sleeping sickness, Chagas disease and malaria, remain a major cause of morbidity and mortality worldwide, but particularly in tropical, developing countries. Controlling these diseases requires a better understanding of host-parasite interactions, including a deep appreciation of parasite distribution in the host. The preferred accumulation of parasites in some tissues of the host has been known for many years, but recent technical advances have allowed a more systematic analysis and quantifications of such tissue tropisms. The functional consequences of tissue tropism remain poorly studied, although it has been associated with important aspects of disease, including transmission enhancement, treatment failure, relapse and clinical outcome. Here, we discuss current knowledge of tissue tropism in Trypanosoma infections in mammals, describe potential mechanisms of tissue entry, comparatively discuss relevant findings from other parasitology fields where tissue tropism has been extensively investigated, and reflect on new questions raised by recent discoveries and their potential impact on clinical treatment and disease control strategies.
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Affiliation(s)
- Sara Silva Pereira
- Instituto de Medicina Molecular-João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa , Lisbon , Portugal
| | - Sandra Trindade
- Instituto de Medicina Molecular-João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa , Lisbon , Portugal
| | - Mariana De Niz
- Instituto de Medicina Molecular-João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa , Lisbon , Portugal
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular-João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa , Lisbon , Portugal
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11
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Sanches-Vaz M, Temporão A, Luis R, Nunes-Cabaço H, Mendes AM, Goellner S, Carvalho T, Figueiredo LM, Prudêncio M. Trypanosoma brucei infection protects mice against malaria. PLoS Pathog 2019; 15:e1008145. [PMID: 31703103 PMCID: PMC6867654 DOI: 10.1371/journal.ppat.1008145] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 11/20/2019] [Accepted: 10/11/2019] [Indexed: 12/22/2022] Open
Abstract
Sleeping sickness and malaria are parasitic diseases with overlapping geographical distributions in sub-Saharan Africa. We hypothesized that the immune response elicited by an infection with Trypanosoma brucei, the etiological agent of sleeping sickness, would inhibit a subsequent infection by Plasmodium, the malaria parasite, decreasing the severity of its associated pathology. To investigate this, we established a new co-infection model in which mice were initially infected with T. brucei, followed by administration of P. berghei sporozoites. We observed that a primary infection by T. brucei significantly attenuates a subsequent infection by the malaria parasite, protecting mice from experimental cerebral malaria and prolonging host survival. We further observed that an ongoing T. brucei infection leads to an accumulation of lymphocyte-derived IFN-γ in the liver, limiting the establishment of a subsequent hepatic infection by P. berghei sporozoites. Thus, we identified a novel host-mediated interaction between two parasitic infections, which may be epidemiologically relevant in regions of Trypanosoma/Plasmodium co-endemicity. Despite the geographical overlap between the parasites that cause sleeping sickness and malaria, the reciprocal impact of a co-infection by T. brucei and Plasmodium had hitherto not been assessed. We hypothesized that the strong immune response elicited by a T. brucei infection could potentially limit the ability of Plasmodium parasites to infect the same host. In this study, we showed that a primary infection by T. brucei significantly attenuates a subsequent infection by the malaria parasite. Importantly, a significant proportion of the co-infected mice do not develop Plasmodium parasitemia, and those few that do, do not display symptoms of severe malaria and survive longer than their singly infected counterparts. We further showed that the prevention or delay in appearance of malaria parasites in the blood results from a dramatic impairment of the preceding liver infection by Plasmodium, which is mediated by the strong immune response mounted against the primary T. brucei infection. Our study provides new insights for a novel inter-pathogen interaction that may bear great epidemiological significance in regions of Trypanosoma/Plasmodium co-endemicity.
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Affiliation(s)
- Margarida Sanches-Vaz
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Adriana Temporão
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Rafael Luis
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Helena Nunes-Cabaço
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - António M. Mendes
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Sarah Goellner
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Tânia Carvalho
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Luisa M. Figueiredo
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- * E-mail: (LMF); (MP)
| | - Miguel Prudêncio
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- * E-mail: (LMF); (MP)
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12
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13
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De Niz M, Meehan GR, Brancucci NM, Marti M, Rotureau B, Figueiredo LM, Frischknecht F. Intravital imaging of host-parasite interactions in skin and adipose tissues. Cell Microbiol 2019; 21:e13023. [PMID: 30825872 PMCID: PMC6590052 DOI: 10.1111/cmi.13023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 02/06/2019] [Accepted: 02/08/2019] [Indexed: 12/20/2022]
Abstract
Intravital microscopy allows the visualisation of how pathogens interact with host cells and tissues in living animals in real time. This method has enabled key advances in our understanding of host-parasite interactions under physiological conditions. A combination of genetics, microscopy techniques, and image analysis have recently facilitated the understanding of biological phenomena in living animals at cellular and subcellular resolution. In this review, we summarise findings achieved by intravital microscopy of the skin and adipose tissues upon infection with various parasites, and we present a view into possible future applications of this method.
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Affiliation(s)
- Mariana De Niz
- Institute of Cell Biology, Heussler GroupUniversity of BernBernSwitzerland
- Wellcome Centre for Integrative ParasitologyUniversity of GlasgowGlasgowUK
| | - Gavin R. Meehan
- Wellcome Centre for Integrative ParasitologyUniversity of GlasgowGlasgowUK
| | - Nicolas M.B. Brancucci
- Malaria Gene Regulation Unit, Department of Medical Parasitology and Infection BiologySwiss Tropical and Public Health InstituteBaselSwitzerland
- University of BaselBaselSwitzerland
| | - Matthias Marti
- Wellcome Centre for Integrative ParasitologyUniversity of GlasgowGlasgowUK
| | - Brice Rotureau
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors, INSERM U1201Institut PasteurParisFrance
| | - Luisa M. Figueiredo
- Faculdade de Medicina, Instituto de Medicina Molecular João Lobo AntunesUniversidade de LisboaLisbonPortugal
| | - Friedrich Frischknecht
- Integrative Parasitology, Centre for Infectious DiseasesUniversity of Heidelberg Medical SchoolHeidelbergGermany
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14
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Büscher P, Bart JM, Boelaert M, Bucheton B, Cecchi G, Chitnis N, Courtin D, Figueiredo LM, Franco JR, Grébaut P, Hasker E, Ilboudo H, Jamonneau V, Koffi M, Lejon V, MacLeod A, Masumu J, Matovu E, Mattioli R, Noyes H, Picado A, Rock KS, Rotureau B, Simo G, Thévenon S, Trindade S, Truc P, Van Reet N. Do Cryptic Reservoirs Threaten Gambiense-Sleeping Sickness Elimination? Trends Parasitol 2018; 34:197-207. [PMID: 29396200 PMCID: PMC5840517 DOI: 10.1016/j.pt.2017.11.008] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/18/2017] [Accepted: 11/27/2017] [Indexed: 12/22/2022]
Abstract
Trypanosoma brucei gambiense causes human African trypanosomiasis (HAT). Between 1990 and 2015, almost 440000 cases were reported. Large-scale screening of populations at risk, drug donations, and efforts by national and international stakeholders have brought the epidemic under control with <2200 cases in 2016. The World Health Organization (WHO) has set the goals of gambiense-HAT elimination as a public health problem for 2020, and of interruption of transmission to humans for 2030. Latent human infections and possible animal reservoirs may challenge these goals. It remains largely unknown whether, and to what extend, they have an impact on gambiense-HAT transmission. We argue that a better understanding of the contribution of human and putative animal reservoirs to gambiense-HAT epidemiology is mandatory to inform elimination strategies.
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Affiliation(s)
- Philippe Büscher
- Department of Biomedical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium.
| | - Jean-Mathieu Bart
- INTERTRYP, IRD, CIRAD, Univ Montpellier, Montpellier, France; Centro Nacional de Medicina Tropical, Instituto de Salud Carlos III, Calle Sinesio Delgado 4, 28029 Madrid, Spain
| | - Marleen Boelaert
- Department of Public Health, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium
| | - Bruno Bucheton
- INTERTRYP, IRD, CIRAD, Univ Montpellier, Montpellier, France
| | - Giuliano Cecchi
- Sub-regional Office for Eastern Africa, Food and Agriculture Organization of the United Nations, CMC Road, Bole Sub City, Kebele 12/13, P O Box 5536, Addis Ababa, Ethiopia
| | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Socinstrasse 57, Postfach, 4002 Basel, Switzerland; University of Basel, Switzerland
| | - David Courtin
- Université Paris Descartes, Institut de Recherche pour le Développement, Unité MERIT, Mère et enfant face aux infections tropicales, 4 avenue de l'Observatoire, 75006 Paris, France
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Prof Egas Moniz, 1649-028 Lisboa, Portugal
| | - José-Ramon Franco
- Control of Neglected Tropical Diseases, Innovative and Intensified Disease Management, World Health Organization, Via Appia 20, 1202 Geneva, Switzerland
| | - Pascal Grébaut
- INTERTRYP, IRD, CIRAD, Univ Montpellier, Montpellier, France
| | - Epco Hasker
- Department of Public Health, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium
| | - Hamidou Ilboudo
- Institut de Recherche sur les Bases Biologiques de la Lutte Intégrée, Centre International de Recherche-Développement sur l'Élevage en zone Subhumide, 01 BP 454 Bobo-Dioulasso 01, Burkina Faso
| | | | - Mathurin Koffi
- Université Jean Lorougnon Guédé, BP 150 Daloa, Côte d'Ivoire
| | - Veerle Lejon
- INTERTRYP, IRD, CIRAD, Univ Montpellier, Montpellier, France
| | - Annette MacLeod
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Henry Wellcome Building, 464 Bearsden Road, Glasgow, UK
| | - Justin Masumu
- Département de Parasitologie, Institut National de Recherche Biomédicale, Avenue de la Démocratie, BP 1197 Kinshasa 1, République Démocratique du Congo
| | - Enock Matovu
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P O Box 7062 Kampala, Uganda
| | - Raffaele Mattioli
- Animal Production and Health Division, Food and Agriculture Organization of the United Nations, Viale delle Terme di Caracalla, 00153 Rome, Italy
| | - Harry Noyes
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Albert Picado
- Foundation for Innovative New Diagnostics, 9 Chemin des Mines, 1202 Geneva, Switzerland
| | - Kat S Rock
- Zeeman Institute for Systems Biology & Infectious Disease Research, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
| | - Brice Rotureau
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, INSERM U1201 and Department of Parasites and Insect Vectors, Institut Pasteur, 25, rue du Docteur Roux, 75015 Paris, France
| | - Gustave Simo
- Department of Biochemistry, Faculty of Science, University of Dschang, P O Box 67 Dschang, Cameroon
| | - Sophie Thévenon
- INTERTRYP, IRD, CIRAD, Univ Montpellier, Montpellier, France; CIRAD, INTERTRYP, Montpellier, France
| | - Sandra Trindade
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Prof Egas Moniz, 1649-028 Lisboa, Portugal
| | - Philippe Truc
- INTERTRYP, IRD, CIRAD, Univ Montpellier, Montpellier, France
| | - Nick Van Reet
- Department of Biomedical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium
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15
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Affiliation(s)
- Filipa Rijo-Ferreira
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Howard Hughes Medical Institute, The University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Joseph S. Takahashi
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Howard Hughes Medical Institute, The University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- * E-mail: (JST); (LMF)
| | - Luisa M. Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- * E-mail: (JST); (LMF)
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16
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Abstract
Cellular metabolic activity is a highly complex, dynamic, regulated process that is influenced by numerous factors, including extracellular environmental signals, nutrient availability and the physiological and developmental status of the cell. The causative agent of sleeping sickness,
Trypanosoma brucei, is an exclusively extracellular protozoan parasite that encounters very different extracellular environments during its life cycle within the mammalian host and tsetse fly insect vector. In order to meet these challenges, there are significant alterations in the major energetic and metabolic pathways of these highly adaptable parasites. This review highlights some of these metabolic changes in this early divergent eukaryotic model organism.
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Affiliation(s)
- Terry K Smith
- Biomedical Sciences Research Complex, University of St Andrews, Fife, UK
| | - Frédéric Bringaud
- Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), UMR 5234 CNRS, Université de Bordeaux, Bordeaux, France
| | - Derek P Nolan
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
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17
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Abstract
Cellular metabolic activity is a highly complex, dynamic, regulated process that is influenced by numerous factors, including extracellular environmental signals, nutrient availability and the physiological and developmental status of the cell. The causative agent of sleeping sickness, Trypanosoma brucei, is an exclusively extracellular protozoan parasite that encounters very different extracellular environments during its life cycle within the mammalian host and tsetse fly insect vector. In order to meet these challenges, there are significant alterations in the major energetic and metabolic pathways of these highly adaptable parasites. This review highlights some of these metabolic changes in this early divergent eukaryotic model organism.
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Affiliation(s)
- Terry K Smith
- Biomedical Sciences Research Complex, University of St Andrews, Fife, UK
| | - Frédéric Bringaud
- Laboratoire de Microbiologie Fondamentale et Pathogénicité (MFP), UMR 5234 CNRS, Université de Bordeaux, Bordeaux, France
| | - Derek P Nolan
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
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18
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Rijo-Ferreira F, Pinto-Neves D, Barbosa-Morais NL, Takahashi JS, Figueiredo LM. Trypanosoma brucei metabolism is under circadian control. Nat Microbiol 2017; 2:17032. [PMID: 28288095 PMCID: PMC5398093 DOI: 10.1038/nmicrobiol.2017.32] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 02/09/2017] [Indexed: 12/16/2022]
Abstract
The Earth's rotation forced life to evolve under cyclic day and night environmental changes. To anticipate such daily cycles, prokaryote and eukaryote free-living organisms evolved intrinsic clocks that regulate physiological and behavioural processes. Daily rhythms have been observed in organisms living within hosts, such as parasites. Whether parasites have intrinsic molecular clocks or whether they simply respond to host rhythmic physiological cues remains unknown. Here, we show that Trypanosoma brucei, the causative agent of human sleeping sickness, has an intrinsic circadian clock that regulates its metabolism in two different stages of the life cycle. We found that, in vitro, ∼10% of genes in T. brucei are expressed with a circadian rhythm. The maximum expression of these genes occurs at two different phases of the day and may depend on a post-transcriptional mechanism. Circadian genes are enriched in cellular metabolic pathways and coincide with two peaks of intracellular adenosine triphosphate concentration. Moreover, daily changes in the parasite population lead to differences in suramin sensitivity, a drug commonly used to treat this infection. These results demonstrate that parasites have an intrinsic circadian clock that is independent of the host, and which regulates parasite biology throughout the day.
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Affiliation(s)
- Filipa Rijo-Ferreira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal.,Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9111, USA.,Graduate Program in Areas of Basic and Applied Biology, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4099-002 Porto, Portugal
| | - Daniel Pinto-Neves
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Nuno L Barbosa-Morais
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Joseph S Takahashi
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9111, USA.,Howard Hughes Medical Institute, The University of Texas Southwestern Medical Center, Dallas, Texas 75390-9111, USA
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
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19
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Tanowitz HB, Scherer PE, Mota MM, Figueiredo LM. Adipose Tissue: A Safe Haven for Parasites? Trends Parasitol 2016; 33:276-284. [PMID: 28007406 DOI: 10.1016/j.pt.2016.11.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 11/17/2016] [Accepted: 11/28/2016] [Indexed: 12/13/2022]
Abstract
Adipose tissue (AT) is no longer regarded as an inert lipid storage, but as an important central regulator in energy homeostasis and immunity. Three parasite species are uniquely associated with AT during part of their life cycle: Trypanosoma cruzi, the causative agent of Chagas disease; Trypanosoma brucei, the causative agent of African sleeping sickness; and Plasmodium spp., the causative agents of malaria. In AT, T. cruzi resides inside adipocytes, T. brucei is found in the interstitial spaces between adipocytes, while Plasmodium spp. infect red blood cells, which may adhere to the blood vessels supplying AT. Here, we discuss how each parasite species adapts to this tissue environment and what the implications are for pathogenesis, clinical manifestations, and therapy.
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Affiliation(s)
- Herbert B Tanowitz
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8549, USA; Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Maria M Mota
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.
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20
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Trindade S, Rijo-Ferreira F, Carvalho T, Pinto-Neves D, Guegan F, Aresta-Branco F, Bento F, Young SA, Pinto A, Van Den Abbeele J, Ribeiro RM, Dias S, Smith TK, Figueiredo LM. Trypanosoma brucei Parasites Occupy and Functionally Adapt to the Adipose Tissue in Mice. Cell Host Microbe 2016; 19:837-48. [PMID: 27237364 PMCID: PMC4906371 DOI: 10.1016/j.chom.2016.05.002] [Citation(s) in RCA: 221] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 03/21/2016] [Accepted: 04/30/2016] [Indexed: 11/17/2022]
Abstract
Trypanosoma brucei is an extracellular parasite that causes sleeping sickness. In mammalian hosts, trypanosomes are thought to exist in two major niches: early in infection, they populate the blood; later, they breach the blood-brain barrier. Working with a well-established mouse model, we discovered that adipose tissue constitutes a third major reservoir for T. brucei. Parasites from adipose tissue, here termed adipose tissue forms (ATFs), can replicate and were capable of infecting a naive animal. ATFs were transcriptionally distinct from bloodstream forms, and the genes upregulated included putative fatty acid β-oxidation enzymes. Consistent with this, ATFs were able to utilize exogenous myristate and form β-oxidation intermediates, suggesting that ATF parasites can use fatty acids as an external carbon source. These findings identify the adipose tissue as a niche for T. brucei during its mammalian life cycle and could potentially explain the weight loss associated with sleeping sickness. T. brucei parasites accumulate in the adipose tissue early after mouse infection Adipose tissue forms (ATFs) can replicate and are capable of infecting naive mice ATFs are transcriptionally distinct and upregulate genes for fatty acid metabolism ATFs can actively uptake exogenous myristate and form β-oxidation intermediates
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Affiliation(s)
- Sandra Trindade
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Filipa Rijo-Ferreira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal; Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA; Graduate Program in Areas of Basic and Applied Biology, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4099-002 Porto, Portugal
| | - Tânia Carvalho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Daniel Pinto-Neves
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Fabien Guegan
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Francisco Aresta-Branco
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Fabio Bento
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Simon A Young
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK
| | - Andreia Pinto
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Jan Van Den Abbeele
- Department of Biomedical Sciences, Unit of Veterinary Protozoology, Institute of Tropical Medicine Antwerp, B-2000 Antwerp, Belgium; Department of Physiology, Laboratory of Zoophysiology, University of Ghent, B-9000 Ghent, Belgium
| | - Ruy M Ribeiro
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA; Guest Professor, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Sérgio Dias
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal
| | - Terry K Smith
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1990-375 Lisboa, Portugal.
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21
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Aresta-Branco F, Pimenta S, Figueiredo LM. A transcription-independent epigenetic mechanism is associated with antigenic switching in Trypanosoma brucei. Nucleic Acids Res 2015; 44:3131-46. [PMID: 26673706 PMCID: PMC4838347 DOI: 10.1093/nar/gkv1459] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 11/28/2015] [Indexed: 12/27/2022] Open
Abstract
Antigenic variation in Trypanosoma brucei relies on periodic switching of variant surface glycoproteins (VSGs), which are transcribed monoallelically by RNA polymerase I from one of about 15 bloodstream expression sites (BES). Chromatin of the actively transcribed BES is depleted of nucleosomes, but it is unclear if this open conformation is a mere consequence of a high rate of transcription, or whether it is maintained by a transcription-independent mechanism. Using an inducible BES-silencing reporter strain, we observed that chromatin of the active BES remains open for at least 24 hours after blocking transcription. This conformation is independent of the cell-cycle stage, but dependent upon TDP1, a high mobility group box protein. For two days after BES silencing, we detected a transient and reversible derepression of several silent BESs within the population, suggesting that cells probe other BESs before commitment to one, which is complete by 48 hours. FACS sorting and subsequent subcloning confirmed that probing cells are switching intermediates capable of returning to the original BES, switch to the probed BES or to a different BES. We propose that regulation of BES chromatin structure is an epigenetic mechanism important for successful antigenic switching.
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Affiliation(s)
- Francisco Aresta-Branco
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Silvia Pimenta
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Luisa M Figueiredo
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
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22
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Pena AC, Pimentel MR, Manso H, Vaz-Drago R, Pinto-Neves D, Aresta-Branco F, Rijo-Ferreira F, Guegan F, Pedro Coelho L, Carmo-Fonseca M, Barbosa-Morais NL, Figueiredo LM. Trypanosoma brucei histone H1 inhibits RNA polymerase I transcription and is important for parasite fitness in vivo. Mol Microbiol 2014; 93:645-63. [PMID: 24946224 PMCID: PMC4285223 DOI: 10.1111/mmi.12677] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2014] [Indexed: 11/30/2022]
Abstract
Trypanosoma brucei is a unicellular parasite that causes sleeping sickness in humans. Most of its transcription is constitutive and driven by RNA polymerase II. RNA polymerase I (Pol I) transcribes not only ribosomal RNA genes, but also protein-encoding genes, including variant surface glycoproteins (VSGs) and procyclins. In T. brucei, histone H1 (H1) is required for VSG silencing and chromatin condensation. However, whether H1 has a genome-wide role in transcription is unknown. Here, using RNA sequencing we show that H1 depletion changes the expression of a specific cohort of genes. Interestingly, the predominant effect is partial loss of silencing of Pol I loci, such as VSG and procyclin genes. Labelling of nascent transcripts with 4-thiouridine showed that H1 depletion does not alter the level of labelled Pol II transcripts. In contrast, the levels of 4sU-labelled Pol I transcripts were increased by two- to sixfold, suggesting that H1 preferentially blocks transcription at Pol I loci. Finally, we observed that parasites depleted of H1 grow almost normally in culture but they have a reduced fitness in mice, suggesting that H1 is important for host-pathogen interactions.
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Affiliation(s)
- Ana C Pena
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, Edifício Egas Moniz, 1649-028, Lisboa, Portugal
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23
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Siegel TN, Hekstra DR, Kemp LE, Figueiredo LM, Lowell JE, Fenyo D, Wang X, Dewell S, Cross GAM. Four histone variants mark the boundaries of polycistronic transcription units in Trypanosoma brucei. Genes Dev 2009; 23:1063-76. [PMID: 19369410 DOI: 10.1101/gad.1790409] [Citation(s) in RCA: 261] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Unusually for a eukaryote, genes transcribed by RNA polymerase II (pol II) in Trypanosoma brucei are arranged in polycistronic transcription units. With one exception, no pol II promoter motifs have been identified, and how transcription is initiated remains an enigma. T. brucei has four histone variants: H2AZ, H2BV, H3V, and H4V. Using chromatin immunoprecipitation (ChIP) and sequencing (ChIP-seq) to examine the genome-wide distribution of chromatin components, we show that histones H4K10ac, H2AZ, H2BV, and the bromodomain factor BDF3 are enriched up to 300-fold at probable pol II transcription start sites (TSSs). We also show that nucleosomes containing H2AZ and H2BV are less stable than canonical nucleosomes. Our analysis also identifies >60 unexpected TSS candidates and reveals the presence of long guanine runs at probable TSSs. Apparently unique to trypanosomes, additional histone variants H3V and H4V are enriched at probable pol II transcription termination sites. Our findings suggest that histone modifications and histone variants play crucial roles in transcription initiation and termination in trypanosomes and that destabilization of nucleosomes by histone variants is an evolutionarily ancient and general mechanism of transcription initiation, demonstrated in an organism in which general pol II transcription factors have been elusive.
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Affiliation(s)
- T Nicolai Siegel
- Laboratory of Molecular Parasitology, The Rockefeller University, New York, New York 10065, USA
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Yang X, Figueiredo LM, Espinal A, Okubo E, Li B. RAP1 is essential for silencing telomeric variant surface glycoprotein genes in Trypanosoma brucei. Cell 2009; 137:99-109. [PMID: 19345190 DOI: 10.1016/j.cell.2009.01.037] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 10/10/2008] [Accepted: 01/14/2009] [Indexed: 01/08/2023]
Abstract
Trypanosoma brucei expresses variant surface glycoprotein (VSG) genes in a strictly monoallelic fashion in its mammalian hosts, but it is unclear how this important virulence mechanism is enforced. Telomere position effect, an epigenetic phenomenon, has been proposed to play a critical role in VSG regulation, yet no telomeric protein has been identified whose disruption led to VSG derepression. We now identify tbRAP1 as an intrinsic component of the T. brucei telomere complex and a major regulator for silencing VSG expression sites (ESs). Knockdown of tbRAP1 led to derepression of all VSGs in silent ESs, but not VSGs located elsewhere, and resulted in stronger derepression of genes located within 10 kb from telomeres than genes located further upstream. This graduated silencing pattern suggests that telomere integrity plays a key role in tbRAP1-dependent silencing and VSG regulation.
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Affiliation(s)
- Xiaofeng Yang
- Department of Biological, Geological, and Environmental Sciences, Center for Gene Regulation in Health and Diseases, Cleveland State University, Cleveland, OH 44115, USA
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Hertz-Fowler C, Figueiredo LM, Quail MA, Becker M, Jackson A, Bason N, Brooks K, Churcher C, Fahkro S, Goodhead I, Heath P, Kartvelishvili M, Mungall K, Harris D, Hauser H, Sanders M, Saunders D, Seeger K, Sharp S, Taylor JE, Walker D, White B, Young R, Cross GAM, Rudenko G, Barry JD, Louis EJ, Berriman M. Telomeric expression sites are highly conserved in Trypanosoma brucei. PLoS One 2008; 3:e3527. [PMID: 18953401 PMCID: PMC2567434 DOI: 10.1371/journal.pone.0003527] [Citation(s) in RCA: 208] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Accepted: 09/23/2008] [Indexed: 11/27/2022] Open
Abstract
Subtelomeric regions are often under-represented in genome sequences of eukaryotes. One of the best known examples of the use of telomere proximity for adaptive purposes are the bloodstream expression sites (BESs) of the African trypanosome Trypanosoma brucei. To enhance our understanding of BES structure and function in host adaptation and immune evasion, the BES repertoire from the Lister 427 strain of T. brucei were independently tagged and sequenced. BESs are polymorphic in size and structure but reveal a surprisingly conserved architecture in the context of extensive recombination. Very small BESs do exist and many functioning BESs do not contain the full complement of expression site associated genes (ESAGs). The consequences of duplicated or missing ESAGs, including ESAG9, a newly named ESAG12, and additional variant surface glycoprotein genes (VSGs) were evaluated by functional assays after BESs were tagged with a drug-resistance gene. Phylogenetic analysis of constituent ESAG families suggests that BESs are sequence mosaics and that extensive recombination has shaped the evolution of the BES repertoire. This work opens important perspectives in understanding the molecular mechanisms of antigenic variation, a widely used strategy for immune evasion in pathogens, and telomere biology.
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Abstract
To evade the host immune system, several pathogens periodically change their cell-surface epitopes. In the African trypanosomes, antigenic variation is achieved by tightly regulating the expression of a multigene family encoding a large repertoire of variant surface glycoproteins (VSGs). Immune evasion relies on two important features: exposing a single type of VSG at the cell surface and periodically and very rapidly switching the expressed VSG. Transcriptional switching between resident telomeric VSG genes does not involve DNA rearrangements, and regulation is probably epigenetic. The histone methyltransferase DOT1B is a nonessential protein that trimethylates lysine 76 of histone H3 in Trypanosoma brucei. Here we report that transcriptionally silent telomeric VSGs become partially derepressed when DOT1B is deleted, whereas nontelomeric loci are unaffected. DOT1B also is involved in the kinetics of VSG switching: in ΔDOT1B cells, the transcriptional switch is so slow that cells expressing two VSGs persist for several weeks, indicating that monoallelic transcription is compromised. We conclude that DOT1B is required to maintain strict VSG silencing and to ensure rapid transcriptional VSG switching, demonstrating that epigenetics plays an important role in regulating antigenic variation in T. brucei. The surface of Trypanosoma brucei, a unicellular parasite that lives in the bloodstream of its mammalian host, is coated with glycoprotein (VSG) molecules. To evade elimination by the immune system, this parasite replaces its coat with one tailored from another glycoprotein variant. Even though there are hundreds of VSG genes in the genome, this process, called antigenic variation, works because all are silenced except for the one that encodes the current coat. In this work, we show that the chromatin-modifying enzyme DOT1B helps to epigenetically regulate the number of VSGs each parasite can have at a time at the surface and how fast each parasite can switch from one coat to another. In parasites lacking DOT1B, silent VSG genes become partially active and the switch from one VSG to another slows down, allowing two different VSGs to appear on the surface of an individual parasite at the same time. Our studies reveal the importance of epigenetics in regulating VSG genes and provide new insights toward the understanding of this unique survival device. Antigenic variation in Trypanosoma brucei relies on monoallelic expression of a multigene family. New evidence shows that a chromatin-modifying enzyme prevents simultaneous expression of different proteins at the parasite's surface.
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Affiliation(s)
- Luisa M Figueiredo
- Laboratory of Molecular Parasitology, the Rockefeller University, New York, New York, United States of America
| | | | - George A.M Cross
- Laboratory of Molecular Parasitology, the Rockefeller University, New York, New York, United States of America
- * To whom correspondence should be addressed. E-mail:
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Martins HR, Figueiredo LM, Valamiel-Silva JCO, Carneiro CM, Machado-Coelho GLL, Vitelli-Avelar DM, Bahia MT, Martins-Filho OA, Macedo AM, Lana M. Persistence of PCR-positive tissue in benznidazole-treated mice with negative blood parasitological and serological tests in dual infections with Trypanosoma cruzi stocks from different genotypes. J Antimicrob Chemother 2008; 61:1319-27. [PMID: 18343804 DOI: 10.1093/jac/dkn092] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES To assess different methodologies to better define an early post-therapeutic cure criterion after benznidazole treatment in BALB/c mice following mixed infection with dual Trypanosoma cruzi genotypes. METHODS According to the classical cure criteria, animals were classified as treated not cured (TNC = 76.4%), treated cured (TC = 12.5%) and dissociated (DIS = 11.1%) using parasitological [fresh blood examination (FBE), blood culture (BC) and blood PCR] and serological methods [conventional serology (CS-ELISA) and non-conventional serology (NCS-FC-ALTA)]. Tissues were also evaluated by PCR. RESULTS FBE was able to detect patent parasitaemia in only 18.1% of TNC and therapeutic failure was detected in 79.1% and 97.2% of TNC by BC and blood PCR, respectively. CS-ELISA should not be used before 3 months after treatment since it may lead to false-negative results. At 3 months after treatment with benznidazole, NCS-FC-ALTA was more efficient for categorizing the groups of treated mice. In the TNC group, although a decreased frequency of PCR-positive tissue was observed in several host tissues, increased positivity was also observed, despite the T. cruzi genotype combination. All TC animals presented at least two positive tissue-PCR results. CONCLUSIONS Our results confirm that NSC-FC-ALTA and blood PCR are the most suitable methods to early detect therapeutic failure in acute murine T. cruzi infection. Additionally, our data show that BC positivity is highly dependent upon the T. cruzi genotype combination. Moreover, our findings demonstrated that PCR tests performed on tissues from animals considered cured after benznidazole treatment still detected T. cruzi DNA, most probably indicating residual infection.
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Affiliation(s)
- H R Martins
- Núcleo de Pesquisas em Ciências Biológicas, Instituto de Ciências Exatas e Biológicas, Ouro Preto, MG, Brazil.
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28
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Figueiredo LM, Rocha EPC, Mancio-Silva L, Prevost C, Hernandez-Verdun D, Scherf A. The unusually large Plasmodium telomerase reverse-transcriptase localizes in a discrete compartment associated with the nucleolus. Nucleic Acids Res 2005; 33:1111-22. [PMID: 15722485 PMCID: PMC549419 DOI: 10.1093/nar/gki260] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Telomerase replicates chromosome ends, a function necessary for maintaining genome integrity. We have identified the gene that encodes the catalytic reverse transcriptase (RT) component of this enzyme in the malaria parasite Plasmodium falciparum (PfTERT) as well as the orthologous genes from two rodent and one simian malaria species. PfTERT is predicted to encode a basic protein that contains the major sequence motifs previously identified in known telomerase RTs (TERTs). At ∼2500 amino acids, PfTERT is three times larger than other characterized TERTs. We observed remarkable sequence diversity between TERT proteins of different Plasmodial species, with conserved domains alternating with hypervariable regions. Immunofluorescence analysis revealed that PfTERT is expressed in asexual blood stage parasites that have begun DNA synthesis. Surprisingly, rather than at telomere clusters, PfTERT typically localizes into a discrete nuclear compartment. We further demonstrate that this compartment is associated with the nucleolus, hereby defined for the first time in P.falciparum.
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Affiliation(s)
- Luisa M. Figueiredo
- Institut Pasteur, Biology of Host Parasite Interaction Unit–CNRS URA258125 rue du Dr Roux, 75724 Paris, France
| | - Eduardo P. C. Rocha
- Unité GGBURA CNRS 2171Institut Pasteur28 rue Dr Roux, 75724 Paris, France
- Atelier de BioInformatique, Université Pierre et Marie Curie12 rue Cuvier, 75005 Paris, France
| | - Liliana Mancio-Silva
- Institut Pasteur, Biology of Host Parasite Interaction Unit–CNRS URA258125 rue du Dr Roux, 75724 Paris, France
| | - Christine Prevost
- Plateforme de Microscopie Electronique, Institut Pasteur25 rue du Dr Roux, 75724 Paris, France
| | | | - Artur Scherf
- Institut Pasteur, Biology of Host Parasite Interaction Unit–CNRS URA258125 rue du Dr Roux, 75724 Paris, France
- To whom correspondence should be addressed. Tel: +33 1 4568 8616; Fax: +33 1 4568 8348;
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Figueiredo LM, Freitas-Junior LH, Bottius E, Olivo-Marin JC, Scherf A. A central role for Plasmodium falciparum subtelomeric regions in spatial positioning and telomere length regulation. EMBO J 2002; 21:815-24. [PMID: 11847128 PMCID: PMC125872 DOI: 10.1093/emboj/21.4.815] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In the protozoan malaria parasite, Plasmodium falciparum, the telomere-associated sequences (TASs) of the 14 linear chromosomes display a similar higher order organization and form clusters of four to seven telomeres localized at the nuclear periphery. Experimental evidence has shown that the physical tethering of chromosome ends enhances the ectopic recombination between gene families involved in antigenic variation and parasite sequestration. Using FISH analysis, we observed that chromosome ends lacking the subtelomeric region are usually delocalized from telomere clusters, but still remain at the nuclear periphery. This indicates that subtelomeric DNA is necessary for cluster formation but is not essential for peripheral positioning. Intriguingly, these truncated chromosomes have unusually long telomeric tracts (up to three times longer than average length), showing that TASs play a role in telomere length regulation. On these chromosomes, the newly formed telomere frequently extends from truncated genes leading, in some cases, to the transcription of telomeric DNA. The implications of both subtelomeric gene expression and nuclear architecture in the virulence of this serious human pathogen are discussed.
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Affiliation(s)
| | | | - Emmanuel Bottius
- Unité de Biologie des Interactions Hôte-Parasite, CNRS URA 1960, Institut Pasteur and
Laboratoire d’Analyse d’Images Quantitative, URA CNRS 1947, Institut Pasteur, 25 rue du Dr Roux, F-75724 Paris Cedex 15, France Present address: Gen Odysse, Les Ulis, F-91974 Courtaboeuf Cedex, France Corresponding author e-mail:
| | - Jean-Christophe Olivo-Marin
- Unité de Biologie des Interactions Hôte-Parasite, CNRS URA 1960, Institut Pasteur and
Laboratoire d’Analyse d’Images Quantitative, URA CNRS 1947, Institut Pasteur, 25 rue du Dr Roux, F-75724 Paris Cedex 15, France Present address: Gen Odysse, Les Ulis, F-91974 Courtaboeuf Cedex, France Corresponding author e-mail:
| | - Artur Scherf
- Unité de Biologie des Interactions Hôte-Parasite, CNRS URA 1960, Institut Pasteur and
Laboratoire d’Analyse d’Images Quantitative, URA CNRS 1947, Institut Pasteur, 25 rue du Dr Roux, F-75724 Paris Cedex 15, France Present address: Gen Odysse, Les Ulis, F-91974 Courtaboeuf Cedex, France Corresponding author e-mail:
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Abstract
New data on the organization of plasmodial telomeres has recently become available. Telomeres form clusters of four to seven heterologous chromosome ends at the nuclear periphery in asexual and sexual parasite stages. This subnuclear compartment promotes gene conversion between members of subtelomeric virulence factor genes in heterologous chromosomes resulting in diversity of antigenic and adhesive phenotypes. This has important implications for parasite survival.
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Affiliation(s)
- A Scherf
- Unité de Biologie des Interactions Hôte-Parasite, CNRS URA 1960, Institut Pasteur, 25, rue du Dr Roux, 75724 Paris Cedex 15, France.
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de Souza ML, Torres LF, Rocha NS, Takahira RK, Mamprim MJ, Burini CH, Bandarra EP, Figueiredo LM. Peritoneal effusion in a dog secondary to visceral mast cell tumor. A case report. Acta Cytol 2001; 45:89-92. [PMID: 11213512 DOI: 10.1159/000327194] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Mast cell tumor, one of the most common skin tumors in dogs, may also be found in visceral sites (mainly spleen and liver). When a visceral mast cell tumor is present, neoplastic mast cells may be found in any effusion secondary to the tumor. Therefore, the diagnosis may be made by cytologic analysis of the effusion. CASE An 8-year-old, spayed, female Siberian husky presented with a peritoneal effusion secondary to a visceral mast cell tumor. Seven months earlier, the dog had presented with a cutaneous nodule diagnosed as a well-differentiated mast cell tumor. The peritoneal fluid was classified as a transudate. Numerous neoplastic mast cells were found in the effusion. Although the mast cell tumor presented with characteristics of the well-differentiated tumor, its biologic behavior was that of a malignant tumor. CONCLUSION Care should be taken to evaluate the prognosis of mast cell tumors in dogs since their biologic behavior is extremely variable.
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Affiliation(s)
- M L de Souza
- Departments of Clinics and of Animal Reproduction and Radiology, Universidade Estadual Paulista, Botucatu, São Paulo, Brazil
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32
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Affiliation(s)
- L M Figueiredo
- Unité de Biologie des Interactions Hôte-Parasite, CNRS URA 1960, Institut Pasteur, Paris, France
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Hatton LS, Eloranta JJ, Figueiredo LM, Takagaki Y, Manley JL, O'Hare K. The Drosophila homologue of the 64 kDa subunit of cleavage stimulation factor interacts with the 77 kDa subunit encoded by the suppressor of forked gene. Nucleic Acids Res 2000; 28:520-6. [PMID: 10606651 PMCID: PMC102530 DOI: 10.1093/nar/28.2.520] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
During mRNA 3' end formation, cleavage stimulation factor (CstF) binds to a GU-rich sequence downstream from the polyadenylation site and helps to stabilise the binding of cleavage-polyadenylation specificity factor (CPSF) to the upstream poly-adenylation sequence (AAUAAA). The 64 kDa subunit of CstF (CstF-64) contains an RNA binding domain and is responsible for the RNA binding activity of CstF. It interacts with CstF-77, which in turn interacts with CPSF. The Drosophila suppressor of forked gene encodes a homologue of CstF-77, and mutations in it affect mRNA 3' end formation in vivo. A Drosophila homologue for CstF-64 has now been isolated, both through homology with the human protein and through protein-protein interaction in yeast with the suppressor of forked gene product. Alignment of CstF-64 homologues shows that the proteins have a conserved N-terminal 200 amino acids, the first half of which is the RNA binding domain with the second half likely to contain the CstF-77 interaction domain; a central region variable in length and rich in glycine, proline and glutamine residues and containing an unusual degenerate repeat motif; and then a conserved C-terminal 50 amino acids. In Drosophila, the CstF-64 gene has a single 63 bp intron, is transcribed throughout development and probably corresponds to l(3)91Cd.
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Affiliation(s)
- L S Hatton
- Department of Biochemistry, Imperial College of Science, London SW7 2AZ, UK and
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Abstract
Hereditary collagen dysplasias comprise a complex group of connective-tissue disorders that result in the reduced tensile strength of affected tissues. These processes are called cutaneous asthenia in the skin of dogs and cats. We report here the case of a crossbred male cat, aged 6 months, that presented with two skin wounds in the region of the right thorax and right iliac tuberosity. The skin of these regions and of the animal's dorsum was hyperextensible, smooth to the touch, and easily torn with minor trauma. Microscopic examination of skin samples revealed reduced dermal connective tissue consisting of shortened and fragmented collagen fibers. Normal fibers were intermingled with altered fibers. Ultrastructural changes in collagen fibers included disorientation of fibrils within the same bundle, marked spacing differences, and variation in the diameter of transverse sections. The fibrils maintained the transverse striations characteristic of normal collagen.
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Affiliation(s)
- J L Sequeira
- Departamento de Clinica Veterinária, Faculdade de Medicina Veterinária e Zootecnia, UNESP, Botucatu, São Paulo, Brazil
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Figueiredo LM, Goulart EM. [Analysis of the efficacy of the maternal breast-feeding incentive program in a peripheric district of Belo Horizonte (Brazil): 1980/1986/1992]. J Pediatr (Rio J) 1995; 71:203-8. [PMID: 14689002 DOI: 10.2223/jped.778] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Three institutions worked together in order to combat early weaning in a peripheric district of Belo Horizonte (Brazil): the Department of Pediatrics of the Faculty of Medicine (Federal University of Minas Gerais), the Secretary of Health of Belo Horizonte and a Brazilian assistential institution ("LBA"). One initial survey, in 1980, documented breast-feeding practices in this community, when there were no systematized actions of incentive to human milk, at local or national levels. Two similar surveys were also conducted, in 1986 and in 1992. In each one, 152 mothers with children under two years old were randomly selected and interviewed. The results showed significant progress in the breast-feeding period in the first six years, and a stabilization between 1986 and 1992. For example: if only 39.0% of the children received human milk for six months or more in 1980, 54.3% received it in 1986 and 52.4% in 1992. In 1980, 80.6% of the children were nourished with cow's milk before three months of age, to 56.5% in 1986 and 56.3% in 1992. Prenatal influence to increase the level of breast-feeding has always been weak. Besides, a reflux was detected in the last few years with regard to the participation of the maternity hospital in the educative process.
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Affiliation(s)
- L M Figueiredo
- Departamento de Pediatria, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte
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