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Marques-da-Silva C, Schmidt-Silva C, Baptista RP, Kurup SP. Inherently Reduced Expression of ASC Restricts Caspase-1 Processing in Hepatocytes and Promotes Plasmodium Infection. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 212:596-606. [PMID: 38149914 PMCID: PMC10872340 DOI: 10.4049/jimmunol.2300440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 12/06/2023] [Indexed: 12/28/2023]
Abstract
Inflammasome-mediated caspase-1 activation facilitates innate immune control of Plasmodium in the liver, thereby limiting the incidence and severity of clinical malaria. However, caspase-1 processing occurs incompletely in both mouse and human hepatocytes and precludes the generation of mature IL-1β or IL-18, unlike in other cells. Why this is so or how it impacts Plasmodium control in the liver has remained unknown. We show that an inherently reduced expression of the inflammasome adaptor molecule apoptosis-associated specklike protein containing CARD (ASC) is responsible for the incomplete proteolytic processing of caspase-1 in murine hepatocytes. Transgenically enhancing ASC expression in hepatocytes enabled complete caspase-1 processing, enhanced pyroptotic cell death, maturation of the proinflammatory cytokines IL-1β and IL-18 that was otherwise absent, and better overall control of Plasmodium infection in the liver of mice. This, however, impeded the protection offered by live attenuated antimalarial vaccination. Tempering ASC expression in mouse macrophages, on the other hand, resulted in incomplete processing of caspase-1. Our work shows how caspase-1 activation and function in host cells are fundamentally defined by ASC expression and offers a potential new pathway to create better disease and vaccination outcomes by modifying the latter.
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Affiliation(s)
- Camila Marques-da-Silva
- Department of Cellular Biology, University of Georgia, Athens, GA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA
| | - Clyde Schmidt-Silva
- Department of Cellular Biology, University of Georgia, Athens, GA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA
| | - Rodrigo P Baptista
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA
| | - Samarchith P Kurup
- Department of Cellular Biology, University of Georgia, Athens, GA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA
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2
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Povelones ML, Holmes NA, Povelones M. A sticky situation: When trypanosomatids attach to insect tissues. PLoS Pathog 2023; 19:e1011854. [PMID: 38128049 PMCID: PMC10734937 DOI: 10.1371/journal.ppat.1011854] [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] [Indexed: 12/23/2023] Open
Abstract
Transmission of trypanosomatids to their mammalian hosts requires a complex series of developmental transitions in their insect vectors, including stable attachment to an insect tissue. While there are many ultrastructural descriptions of attached cells, we know little about the signaling events and molecular mechanisms involved in this process. Each trypanosomatid species attaches to a specific tissue in the insect at a particular stage of its life cycle. Attachment is mediated by the flagellum, which is modified to accommodate a filament-rich plaque within an expanded region of the flagellar membrane. Attachment immediately precedes differentiation to the mammal-infectious stage and in some cases a direct mechanistic link has been demonstrated. In this review, we summarize the current state of knowledge of trypanosomatid attachment in insects, including structure, function, signaling, candidate molecules, and changes in gene expression. We also highlight remaining questions about this process and how the field is poised to address them through modern approaches.
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Affiliation(s)
- Megan L. Povelones
- Department of Biology, Villanova University, Villanova, Pennsylvania, United States of America
| | - Nikki A. Holmes
- Department of Biology, Villanova University, Villanova, Pennsylvania, United States of America
| | - Michael Povelones
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
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3
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Perumal N, White B, Sanchez-Valdez F, Tarleton RL. cGAS-STING Pathway Activation during Trypanosoma cruzi Infection Leads to Tissue-Dependent Parasite Control. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 211:1123-1133. [PMID: 37603014 PMCID: PMC10783805 DOI: 10.4049/jimmunol.2300373] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 07/31/2023] [Indexed: 08/22/2023]
Abstract
Host cell invasion by Trypanosoma cruzi is a markedly silent process, with limited host transcriptional changes indicative of innate immune recognition, except for a modest type I IFN (IFN-I) response. In this study, we show that T. cruzi-induced IFN-β production was nearly abolished in primary murine cGAS-/- or stimulator of IFN genes (STING)-deficient (STINGGt) macrophages and fibroblasts. T. cruzi infection did not impact the ability of IFN-regulatory factor reporter macrophages to respond to classical cGAS-STING agonists, indicating that the limited IFN-β induction is not due to active parasite suppression. cGAS-/-, STINGGt, and IFN-α/β receptor-/- (IFNAR-/-) macrophages infected with T. cruzi yielded significantly higher numbers of amastigotes compared with wild-type macrophages; however, the impact of the STING pathway during infection in vivo is more complex. Despite an initial increase in parasite growth, STINGGt and IFNAR-/- mice ultimately had lower parasite burden in footpads as compared with wild-type mice, demonstrating a role for IFN-I expression in potentiating parasite growth at the infection site. STING pathway activation had little impact on parasite levels in the skeletal muscle; however, in the heart, cGAS-/- and STINGGt mice, but not IFNAR-/- mice, accumulated higher acute parasite loads, suggesting a protective role of STING sensing of T. cruzi in this organ that was independent of IFN-I. Together, these results demonstrate that host cGAS-STING senses T. cruzi infection, enhancing parasite growth at the site of entry, and contributes to acute-phase parasite restriction in the heart, a major site of tissue damage in chronic T. cruzi infection.
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Affiliation(s)
- Natasha Perumal
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA
- Department of Cellular Biology, University of Georgia, Athens, GA
| | - Brooke White
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA
| | | | - Rick L Tarleton
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA
- Department of Cellular Biology, University of Georgia, Athens, GA
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4
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Won MM, Krüger T, Engstler M, Burleigh BA. The Intracellular Amastigote of Trypanosoma cruzi Maintains an Actively Beating Flagellum. mBio 2023; 14:e0355622. [PMID: 36840555 PMCID: PMC10128032 DOI: 10.1128/mbio.03556-22] [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] [Received: 12/20/2022] [Accepted: 02/02/2023] [Indexed: 02/25/2023] Open
Abstract
Throughout its complex life cycle, the uniflagellate parasitic protist, Trypanosoma cruzi, adapts to different host environments by transitioning between elongated motile extracellular stages and a nonmotile intracellular amastigote stage that replicates in the cytoplasm of mammalian host cells. Intracellular T. cruzi amastigotes retain a short flagellum that extends beyond the opening of the flagellar pocket with access to the extracellular milieu. Contrary to the long-held view that the T. cruzi amastigote flagellum is inert, we report that this organelle is motile and displays quasiperiodic beating inside mammalian host cells. Kymograph analysis determined an average flagellar beat frequency of ~0.7 Hz for intracellular amastigotes and similar beat frequencies for extracellular amastigotes following their isolation from host cells. Inhibitor studies reveal that flagellar motility in T. cruzi amastigotes is critically dependent on parasite mitochondrial oxidative phosphorylation. These novel observations reveal that flagellar motility is an intrinsic property of T. cruzi amastigotes and suggest that this organelle may play an active role in the parasite infection process. IMPORTANCE Understanding the interplay between intracellular pathogens and their hosts is vital to the development of new treatments and preventive strategies. The intracellular "amastigote" stage of the Chagas disease parasite, Trypanosoma cruzi, is a critical but understudied parasitic life stage. Previous work established that cytosolically localized T. cruzi amastigotes engage physically and selectively with host mitochondria using their short, single flagellum. The current study was initiated to examine the dynamics of the parasite flagellum-host mitochondrial interaction through live confocal imaging and led to the unexpected discovery that the T. cruzi amastigote flagellum is motile.
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Affiliation(s)
- Madalyn M. Won
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Timothy Krüger
- Department of Cell and Developmental Biology, Biozentrum, University of Würzburg, Germany
| | - Markus Engstler
- Department of Cell and Developmental Biology, Biozentrum, University of Würzburg, Germany
| | - Barbara A. Burleigh
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
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5
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Bunkofske ME, Perumal N, White B, Strauch EM, Tarleton R. Epitopes in the Glycosylphosphatidylinositol Attachment Signal Peptide of Trypanosoma cruzi Mucin Proteins Generate Robust but Delayed and Nonprotective CD8+ T Cell Responses. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 210:420-430. [PMID: 36603035 PMCID: PMC9898211 DOI: 10.4049/jimmunol.2200723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 12/05/2022] [Indexed: 01/06/2023]
Abstract
Infection with the protozoan parasite Trypanosoma cruzi elicits substantial CD8+ T cell responses that disproportionately target epitopes encoded in the large trans-sialidase (TS) gene family. Within the C57BL/6 infection model, a significant proportion (30-40%) of the T. cruzi-specific CD8+ T cell response targets two immunodominant TS epitopes, TSKb18 and TSKb20. However, both TS-specific CD8+ T cell responses are dispensable for immune control, and TS-based vaccines have no demonstrable impact on parasite persistence, a determinant of disease. Besides TS, the specificity and protective capacity of CD8+ T cells that mediate immune control of T. cruzi infection are unknown. With the goal of identifying alternative CD8+ T cell targets, we designed and screened a representative set of genome-wide, in silico-predicted epitopes. Our screen identified a previously uncharacterized, to our knowledge, T cell epitope MUCKb25, found within mucin family proteins, the third most expanded large gene family in T. cruzi. The MUCKb25-specific response was characterized by delayed kinetics, relative to TS-specific responses, and extensive cross-reactivity with a large number of endogenous epitope variants. Similar to TS-specific responses, the MUCKb25 response was dispensable for control of the infection, and vaccination to generate MUCK-specific CD8+ T cells failed to confer protection. The lack of protection by MUCK vaccination was partly attributed to the fact that MUCKb25-specific T cells exhibit limited recognition of T. cruzi-infected host cells. Overall, these results indicate that the CD8+ T cell compartment in many T. cruzi-infected mice is occupied by cells with minimal apparent effector potential.
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Affiliation(s)
- Molly E. Bunkofske
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Natasha Perumal
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Brooke White
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Eva-Maria Strauch
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA 30602, USA
| | - Rick Tarleton
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
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6
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Biscari L, Kaufman CD, Farré C, Huhn V, Pacini MF, Balbi CB, Gómez KA, Pérez AR, Alloatti A. Immunization With Lipopolysaccharide-Activated Dendritic Cells Generates a Specific CD8+ T Cell Response That Confers Partial Protection Against Infection With Trypanosoma cruzi. Front Cell Infect Microbiol 2022; 12:897133. [PMID: 35903201 PMCID: PMC9318436 DOI: 10.3389/fcimb.2022.897133] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 06/17/2022] [Indexed: 11/13/2022] Open
Abstract
Lipopolysaccharide (LPS) induces the activation of dendritic cells (DCs) throughout the engagement of toll-like receptor 4. LPS-activated DCs show increased capacity to process and present pathogen-derived antigens to activate naïve T cells. DCs-based vaccines have been successfully used to treat some cancer types, and lately transferred to the field of infectious diseases, in particular against HIV. However, there is no vaccine or DC therapy for any parasitic disease that is currently available. The immune response against Trypanosoma cruzi substantially relies on T cells, and both CD4+ and CD8+ T lymphocytes are required to control parasite growth. Here, we develop a vaccination strategy based on DCs derived from bone marrow, activated with LPS and loaded with TsKb20, an immunodominant epitope of the trans-sialidase family of proteins. We extensively characterized the CD8+ T cell response generated after immunization and compared three different readouts: a tetramer staining, ELISpot and Activation-Induced Marker (AIM) assays. To our knowledge, this work shows for the first time a proper set of T cell markers to evaluate specific CD8+ T cell responses in mice. We also show that our immunization scheme confers protection against T. cruzi, augmenting survival and reducing parasite burden in female but not male mice. We conclude that the immunization with LPS-activated DCs has the potential to prime significant CD8+ T cell responses in C57BL/6 mice independently of the sex, but this response will only be effective in female, possibly due to mice sexual dimorphisms in the response generated against T. cruzi.
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Affiliation(s)
- Lucía Biscari
- Instituto de Inmunología Clínica y Experimental de Rosario (IDICER), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario, Rosario, Argentina
| | - Cintia Daniela Kaufman
- Instituto de Inmunología Clínica y Experimental de Rosario (IDICER), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario, Rosario, Argentina
| | - Cecilia Farré
- Instituto de Inmunología Clínica y Experimental de Rosario (IDICER), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario, Rosario, Argentina
- Centro de Investigación y Producción de Reactivos Biológicos, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Victoria Huhn
- Instituto de Inmunología Clínica y Experimental de Rosario (IDICER), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario, Rosario, Argentina
| | - María Florencia Pacini
- Instituto de Inmunología Clínica y Experimental de Rosario (IDICER), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario, Rosario, Argentina
| | - Camila Bulfoni Balbi
- Instituto de Inmunología Clínica y Experimental de Rosario (IDICER), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario, Rosario, Argentina
| | - Karina Andrea Gómez
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular Dr. Héctor N. Torres (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Ana Rosa Pérez
- Instituto de Inmunología Clínica y Experimental de Rosario (IDICER), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario, Rosario, Argentina
- Centro de Investigación y Producción de Reactivos Biológicos, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Andrés Alloatti
- Instituto de Inmunología Clínica y Experimental de Rosario (IDICER), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Rosario, Rosario, Argentina
- *Correspondence: Andrés Alloatti,
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7
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Jones KM, Poveda C, Versteeg L, Bottazzi ME, Hotez PJ. Preclinical advances and the immunophysiology of a new therapeutic chagas disease vaccine. Expert Rev Vaccines 2022; 21:1185-1203. [PMID: 35735065 DOI: 10.1080/14760584.2022.2093721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Chronic infection with the protozoal parasite Trypanosoma cruzi leads to a progressive cardiac disease, known as chronic Chagasic cardiomyopathy (CCC). A new therapeutic Chagas disease vaccine is in development to augment existing antiparasitic chemotherapy drugs. AREAS COVERED We report on our current understanding of the underlying immunologic and physiologic mechanisms that lead to CCC, including parasite immune escape mechanisms that allow persistence and the subsequent inflammatory and fibrotic processes that lead to clinical disease. We report on vaccine design and the observed immunotherapeutic effects including induction of a balanced TH1/TH2/TH17 immune response that leads to reduced parasite burdens and tissue pathology. Further, we report vaccine-linked chemotherapy, a dose sparing strategy to further reduce parasite burdens and tissue pathology. EXPERT OPINION Our vaccine-linked chemotherapeutic approach is a multimodal treatment strategy, addressing both the parasite persistence and the underlying deleterious host inflammatory and fibrotic responses that lead to cardiac dysfunction. In targeting treatment towards patients with chronic indeterminate or early determinate Chagas disease, this vaccine-linked chemotherapeutic approach will be highly economical and will reduce the global disease burden and deaths due to CCC.
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Affiliation(s)
- Kathryn M Jones
- Texas Children's Hospital Center for Vaccine Development, Department of Pediatrics, Division of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America.,Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Cristina Poveda
- Texas Children's Hospital Center for Vaccine Development, Department of Pediatrics, Division of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America.,Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Leroy Versteeg
- Texas Children's Hospital Center for Vaccine Development, Department of Pediatrics, Division of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America.,Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America.,Cell Biology and Immunology Group, Wageningen University & Research, De Elst 1, 6708 WD Wageningen, The Netherlands
| | - Maria Elena Bottazzi
- Texas Children's Hospital Center for Vaccine Development, Department of Pediatrics, Division of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America.,Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America.,Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Peter J Hotez
- Texas Children's Hospital Center for Vaccine Development, Department of Pediatrics, Division of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America.,Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America.,Department of Biology, Baylor University, Waco, Texas, United States of America.,James A. Baker III Institute for Public Policy, Rice University, Houston, Texas, United States of America.,Hagler Institute for Advanced Study at Texas A&M University, College Station, Texas, United States of America
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8
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Martín-Escolano J, Marín C, Rosales MJ, Tsaousis AD, Medina-Carmona E, Martín-Escolano R. An Updated View of the Trypanosoma cruzi Life Cycle: Intervention Points for an Effective Treatment. ACS Infect Dis 2022; 8:1107-1115. [PMID: 35652513 PMCID: PMC9194904 DOI: 10.1021/acsinfecdis.2c00123] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Chagas disease (CD)
is a parasitic, systemic, chronic, and often
fatal illness caused by infection with the protozoan Trypanosoma
cruzi. The World Health Organization classifies CD as the
most prevalent of poverty-promoting neglected tropical diseases, the
most important parasitic one, and the third most infectious disease
in Latin America. Currently, CD is a global public health issue that
affects 6–8 million people. However, the current approved treatments
are limited to two nitroheterocyclic drugs developed more than 50
years ago. Many efforts have been made in recent decades to find new
therapies, but our limited understanding of the infection process,
pathology development, and long-term nature of this disease has made
it impossible to develop new drugs, effective treatment, or vaccines.
This Review aims to provide a comprehensive update on our understanding
of the current life cycle, new morphological forms, and genetic diversity
of T. cruzi, as well as identify intervention points
in the life cycle where new drugs and treatments could achieve a parasitic
cure.
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Affiliation(s)
- Javier Martín-Escolano
- Unit of Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, E41013 Seville, Spain
| | - Clotilde Marín
- Department of Parasitology, University of Granada, Severo Ochoa s/n, 18071 Granada, Spain
| | - María J. Rosales
- Department of Parasitology, University of Granada, Severo Ochoa s/n, 18071 Granada, Spain
| | - Anastasios D. Tsaousis
- Laboratory of Molecular & Evolutionary Parasitology, RAPID group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, U.K
| | - Encarnación Medina-Carmona
- Department of Physical Chemistry, University of Granada, 18071 Granada, Spain
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, U.K
| | - Rubén Martín-Escolano
- Laboratory of Molecular & Evolutionary Parasitology, RAPID group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, U.K
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Differentiating Trypanosoma cruzi in a Host Mammalian Cell Imaged in Aqueous Liquid by Atmospheric Scanning Electron Microscopy. Microbiol Spectr 2022; 10:e0141321. [PMID: 34985339 PMCID: PMC8729778 DOI: 10.1128/spectrum.01413-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Atmospheric Scanning Electron Microscopy (ASEM) is a powerful tool to observe a wet specimen at high resolution under atmospheric pressure. Here, we visualized a protozoan parasite Trypanosoma cruzi over the course of its infection cycle in the host mammalian cell. This is the first observation of intracellular parasite using a liquid-phase EM. Unlike regular SEM, aldehyde-fixed cell body of T. cruzi appears translucent, allowing the visualization of internal structures such as kinetoplast of trypomastigote and nucleus of amastigote. Plasma membrane of the host mammalian cell also appears translucent, which enabled direct observation of differentiating intracellular parasites and dynamic change of host cellular structures in their near-natural states. Various water-rich structures including micro- and macro- vesicles were visualized around T. cruzi. In addition, Correlative Light and Electron Microscopy exploiting open sample dish of ASEM allowed identification of parasite nucleus and transfected fluorescence-labeled parasites soon after internalization, while location of this morphological intermediate was otherwise obscure. Successful visualization of the differentiation of T. cruzi within the host cell demonstrated here opens up the possibility of using ASEM for observation of variety of intracellular parasites. IMPORTANCE Using Atmospheric Scanning Electron Microscopy (ASEM), we visualized interaction between infectious stage of Trypanosoma cruzi and completely intact host mammalian cell. Plasma membrane appears translucent under ASEM, which not only enables direct observation of T. cruzi within its host cell, but also reveals internal structures of the parasite itself. Sample deformation is minimal, since the specimen remains hydrated under atmospheric pressure at all times. This nature of ASEM, along with the open structure of ASEM sample dish, is suited for correlative light-electron microscopy, which can further be exploited in identification of fluorescent protein in the intracellular parasites.
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10
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Versteeg L, Adhikari R, Poveda C, Villar-Mondragon MJ, Jones KM, Hotez PJ, Bottazzi ME, Tijhaar E, Pollet J. Location and expression kinetics of Tc24 in different life stages of Trypanosoma cruzi. PLoS Negl Trop Dis 2021; 15:e0009689. [PMID: 34478444 PMCID: PMC8415617 DOI: 10.1371/journal.pntd.0009689] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 07/27/2021] [Indexed: 12/03/2022] Open
Abstract
Tc24-C4, a modified recombinant flagellar calcium-binding protein of Trypanosoma cruzi, is under development as a therapeutic subunit vaccine candidate to prevent or delay progression of chronic Chagasic cardiomyopathy. When combined with Toll-like receptor agonists, Tc24-C4 immunization reduces parasitemia, parasites in cardiac tissue, and cardiac fibrosis and inflammation in animal models. To support further research on the vaccine candidate and its mechanism of action, murine monoclonal antibodies (mAbs) against Tc24-C4 were generated. Here, we report new findings made with mAb Tc24-C4/884 that detects Tc24-WT and Tc24-C4, as well as native Tc24 in T. cruzi on ELISA, western blots, and different imaging techniques. Surprisingly, detection of Tc24 by Tc24-C/884 in fixed T. cruzi trypomastigotes required permeabilization of the parasite, revealing that Tc24 is not exposed on the surface of T. cruzi, making a direct role of antibodies in the induced protection after Tc24-C4 immunization less likely. We further observed that after immunostaining T. cruzi-infected cells with mAb Tc24-C4/884, the expression of Tc24 decreases significantly when T. cruzi trypomastigotes enter host cells and transform into amastigotes. However, Tc24 is then upregulated in association with parasite flagellar growth linked to re-transformation into the trypomastigote form, prior to host cellular escape. These observations are discussed in the context of potential mechanisms of vaccine immunity.
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Affiliation(s)
- Leroy Versteeg
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
- Cell Biology and Immunology Group, Wageningen University, Wageningen, The Netherlands
| | - Rakesh Adhikari
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
| | - Cristina Poveda
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
| | - Maria Jose Villar-Mondragon
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
| | - Kathryn M. Jones
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
| | - Peter J. Hotez
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Maria Elena Bottazzi
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Biology, Baylor University, Waco, Texas, United States of America
| | - Edwin Tijhaar
- Cell Biology and Immunology Group, Wageningen University, Wageningen, The Netherlands
| | - Jeroen Pollet
- Department of Pediatrics, National School of Tropical Medicine, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States of America
- Texas Children’s Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, Texas, United States of America
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11
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Taylor MC, Ward AI, Olmo F, Francisco AF, Jayawardhana S, Costa FC, Lewis MD, Kelly JM. Bioluminescent:Fluorescent Trypanosoma cruzi Reporter Strains as Tools for Exploring Chagas Disease Pathogenesis and Drug Activity. Curr Pharm Des 2021; 27:1733-1740. [PMID: 33234096 DOI: 10.2174/1381612826666201124113214] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/16/2020] [Accepted: 07/23/2020] [Indexed: 11/22/2022]
Abstract
Chagas disease results from infection with the trypanosomatid parasite Trypanosoma cruzi. Progress in developing new drugs has been hampered by the long term and complex nature of the condition and by our limited understanding of parasite biology. Technical difficulties in assessing the parasite burden during the chronic stage of infection have also proven to be a particular challenge. In this context, the development of noninvasive, highly sensitive bioluminescence imaging procedures based on parasites that express a red-shifted luciferase has greatly enhanced our ability to monitor infections in experimental models. Applications of this methodology have led to new insights into tissue tropism and infection dynamics and have been a major driver in drug development. The system has been further modified by the generation of parasite reporter lines that express bioluminescent:fluorescent fusion proteins, an advancement that has allowed chronic infections in mice to be examined at a cellular level. By exploiting bioluminescence, to identify the rare sites of tissue infection, and fluorescence to detect T. cruzi at the level of individual host cells in histological sections, it has been possible to investigate the replication and differentiation status of parasites in vivo and to examine the cellular environment of infection foci. In combination, these data provide a framework for the detailed dissection of disease pathogenesis and drug activity.
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Affiliation(s)
- Martin C Taylor
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - Alexander I Ward
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - Francisco Olmo
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - Amanda F Francisco
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - Shiromani Jayawardhana
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - Fernanda C Costa
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - Michael D Lewis
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
| | - John M Kelly
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom
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12
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Alcantara CL, de Souza W, Cunha E Silva NL. The cytostome-cytopharynx complex of intracellular and extracellular amastigotes of Trypanosoma cruzi exhibit structural and functional differences. Cell Microbiol 2021; 23:e13346. [PMID: 33900003 DOI: 10.1111/cmi.13346] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 04/13/2021] [Accepted: 04/22/2021] [Indexed: 01/01/2023]
Abstract
Endocytosis in Trypanosoma cruzi is mainly performed through a specialised membrane domain called cytostome-cytopharynx complex. Its ultrastructure and dynamics in endocytosis are well characterized in epimastigotes, being absent in trypomastigotes, that lack endocytic activity. Intracellular amastigotes also possess a cytostome-cytopharynx but participation in endocytosis of these forms is not clear. Extracellular amastigotes can be obtained from the supernatant of infected cells or in vitro amastigogenesis. These amastigotes share biochemical and morphological features with intracellular amastigotes but retain trypomastigote's ability to establish infection. We analysed and compared the ultrastructure of the cytostome-cytopharynx complex of intracellular amastigotes and extracellular amastigotes using high-resolution tridimensional electron microscopy techniques. We compared the endocytic ability of intracellular amastigotes, obtained through host cell lysis, with that of extracellular amastigotes. Intracellular amastigotes showed a cytostome-cytopharynx complex similar to epimastigotes'. However, after isolation, the complex undergoes ultrastructural modifications that progressively took to an impairment of endocytosis. Extracellular amastigotes do not possess a cytostome-cytopharynx complex nor the ability to endocytose. Those observations highlight morpho functional differences between intra and extracellular amastigotes regarding an important structure related to cell metabolism. TAKE AWAYS: T. cruzi intracellular amastigotes endocytose through the cytostome-cytopharynx complex. The cytostome-cytopharynx complex of intracellular amastigotes is ultrastructurally similar to the epimastigote. Intracellular amastigotes, once outside the host cell, disassembles the cytostome-cytopharynx membrane domain. Extracellular amastigotes do not possess a cytostome-cytopharynx either the ability to endocytose.
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Affiliation(s)
- Carolina L Alcantara
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.,Núcleo de Biologia Estrutural e Bioimagens (CENABIO)-Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Biomagens (INBEB), Rio de Janeiro, Rio de Janeiro, Brazil
| | - Wanderley de Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.,Núcleo de Biologia Estrutural e Bioimagens (CENABIO)-Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Biomagens (INBEB), Rio de Janeiro, Rio de Janeiro, Brazil
| | - Narcisa L Cunha E Silva
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.,Núcleo de Biologia Estrutural e Bioimagens (CENABIO)-Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Biomagens (INBEB), Rio de Janeiro, Rio de Janeiro, Brazil
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13
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Pérez-Mazliah D, Ward AI, Lewis MD. Host-parasite dynamics in Chagas disease from systemic to hyper-local scales. Parasite Immunol 2020; 43:e12786. [PMID: 32799361 DOI: 10.1111/pim.12786] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 08/11/2020] [Accepted: 08/13/2020] [Indexed: 12/14/2022]
Abstract
Trypanosoma cruzi is a remarkably versatile parasite. It can parasitize almost any nucleated cell type and naturally infects hundreds of mammal species across much of the Americas. In humans, it is the cause of Chagas disease, a set of mainly chronic conditions predominantly affecting the heart and gastrointestinal tract, which can progress to become life threatening. Yet around two thirds of infected people are long-term asymptomatic carriers. Clinical outcomes depend on many factors, but the central determinant is the nature of the host-parasite interactions that play out over the years of chronic infection in diverse tissue environments. In this review, we aim to integrate recent developments in the understanding of the spatial and temporal dynamics of T. cruzi infections with established and emerging concepts in host immune responses in the corresponding phases and tissues.
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Affiliation(s)
- Damián Pérez-Mazliah
- York Biomedical Research Institute, Hull York Medical School, University of York, York, UK
| | - Alexander I Ward
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Michael D Lewis
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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14
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Taylor MC, Ward A, Olmo F, Jayawardhana S, Francisco AF, Lewis MD, Kelly JM. Intracellular DNA replication and differentiation of Trypanosoma cruzi is asynchronous within individual host cells in vivo at all stages of infection. PLoS Negl Trop Dis 2020; 14:e0008007. [PMID: 32196491 PMCID: PMC7112235 DOI: 10.1371/journal.pntd.0008007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 04/01/2020] [Accepted: 02/29/2020] [Indexed: 12/21/2022] Open
Abstract
Investigations into intracellular replication and differentiation of Trypanosoma cruzi within the mammalian host have been restricted by limitations in our ability to detect parasitized cells throughout the course of infection. We have overcome this problem by generating genetically modified parasites that express a bioluminescent/fluorescent fusion protein. By combining in vivo imaging and confocal microscopy, this has enabled us to routinely visualise murine infections at the level of individual host cells. These studies reveal that intracellular parasite replication is an asynchronous process, irrespective of tissue location or disease stage. Furthermore, using TUNEL assays and EdU labelling, we demonstrate that within individual infected cells, replication of both mitochondrial (kDNA) and nuclear genomes is not co-ordinated within the parasite population, and that replicating amastigotes and non-replicating trypomastigotes can co-exist in the same cell. Finally, we report the presence of distinct non-canonical morphological forms of T. cruzi in the mammalian host. These appear to represent transitional forms in the amastigote to trypomastigote differentiation process. Therefore, the intracellular life-cycle of T. cruzi in vivo is more complex than previously realised, with potential implications for our understanding of disease pathogenesis, immune evasion and drug development. Dissecting the mechanisms involved will be an important experimental challenge. Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, is becoming an emerging threat in non-endemic countries and establishing new foci in endemic countries. The treatment available has not changed significantly in over 40 years. Therefore, there is an urgent need for a greater understanding of parasite biology and disease pathogenesis to identify new therapeutic targets and to maximise the efficient use of existing drugs. We have used genetically modified strains of T. cruzi carrying a bioluminescence/fluorescence dual reporter fusion gene to monitor parasite replication in vivo during both acute and chronic infections in a mouse model. Utilising TUNEL assays for mitochondrial DNA replication and EdU incorporation for total DNA replication, we have found that parasite division within infected cells is asynchronous in all phases of infection. Differentiation also appears to be uncoordinated, with replicating amastigotes co-existing with non-dividing trypomastigotes in the same host cell.
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Affiliation(s)
- Martin C. Taylor
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail:
| | - Alexander Ward
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Francisco Olmo
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Shiromani Jayawardhana
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Amanda F. Francisco
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Michael D. Lewis
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - John M. Kelly
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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15
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Sykes ML, Hilko DH, Kung LI, Poulsen SA, Avery VM. Investigation of pyrimidine nucleoside analogues as chemical probes to assess compound effects on the proliferation of Trypanosoma cruzi intracellular parasites. PLoS Negl Trop Dis 2020; 14:e0008068. [PMID: 32163414 PMCID: PMC7112222 DOI: 10.1371/journal.pntd.0008068] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 04/01/2020] [Accepted: 01/15/2020] [Indexed: 02/05/2023] Open
Abstract
Trypanosoma cruzi parasites utilise de novo pyrimidine biosynthesis to produce DNA and survive within mammalian host cells. This pathway can be hijacked to assess the replication of intracellular parasites with the exogenous addition of a DNA specific probe. To identify suitable probe compounds for this application, a collection of pyrimidine nucleoside analogues was assessed for incorporation into T. cruzi intracellular amastigote DNA using image-based technology and script-based analysis. Associated mammalian cell toxicity of these compounds was also determined against both the parasite host cells (3T3 cells) and HEK293 cells. Incorporation of 5-ethynyl-2′-deoxyuridine (EdU) into parasite DNA was the most effective of the probes tested, with minimal growth inhibition observed following either two or four hours EdU exposure. EdU was subsequently utilised as a DNA probe, followed by visualisation with click chemistry to a fluorescent azide, to assess the impact of drugs and compounds with previously demonstrated activity against T. cruzi parasites, on parasite replication. The inhibitory profiles of these molecules highlight the benefit of this approach for identifying surviving parasites post-treatment in vitro and classifying compounds as either fast or slow-acting. F-ara-EdU resulted in <50% activity observed against T. cruzi amastigotes following 48 hours incubation, at 73 μM. Collectively, this supports the further development of pyrimidine nucleosides as chemical probes to investigate replication of the parasite T. cruzi. Chagas disease occurs within 21 countries in the Americas, causes over 10, 000 deaths per year and a further 25 million people are at risk of being infected. The cause of Chagas disease is Trypanosoma cruzi, a single celled protozoan parasite, which enters the bloodstream of a host by the bite of a “kissing bug”. In advanced disease stages, the parasite hides in heart and gut tissue and is difficult to treat. Identifying the replicative ability of these parasites is important to understanding Chagas disease progression and the effectiveness of compounds and drugs for treatment. By testing a panel of nucleoside analogues that may incorporate into DNA during synthesis, we developed an image-based method with a fluorescently-labelled DNA probe to identify replicating parasites. This method has effectively shown that drugs used to treat the parasite are able to clear intracellular infection, whilst a compound that was not efficacious in clinical trials leaves replicating T. cruzi behind. This methodology can be used to understand the action of further compounds and supports the identification of new, less toxic probes to assess intracellular parasite replication.
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Affiliation(s)
- Melissa Louise Sykes
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, Australia
| | - David Hugh Hilko
- Chemical Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, Australia
| | - Livia Isabella Kung
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, Australia.,Institute of Molecular Health Sciences, ETH Zurich, Switzerland
| | - Sally-Ann Poulsen
- Chemical Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, Australia
| | - Vicky Marie Avery
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, Australia
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16
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Mandacaru SC, Queiroz RML, Alborghetti MR, de Oliveira LS, de Lima CMR, Bastos IMD, Santana JM, Roepstorff P, Ricart CAO, Charneau S. Exoproteome profiling of Trypanosoma cruzi during amastigogenesis early stages. PLoS One 2019; 14:e0225386. [PMID: 31756194 PMCID: PMC6874342 DOI: 10.1371/journal.pone.0225386] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 11/04/2019] [Indexed: 11/20/2022] Open
Abstract
Chagas disease is caused by the protozoan Trypanosoma cruzi, affecting around 8 million people worldwide. After host cell invasion, the infective trypomastigote form remains 2–4 hours inside acidic phagolysosomes to differentiate into replicative amastigote form. In vitro acidic-pH-induced axenic amastigogenesis was used here to study this step of the parasite life cycle. After three hours of trypomastigote incubation in amastigogenesis promoting acidic medium (pH 5.0) or control physiological pH (7.4) medium samples were subjected to three rounds of centrifugation followed by ultrafiltration of the supernatants. The resulting exoproteome samples were trypsin digested and analysed by nano flow liquid chromatography coupled to tandem mass spectrometry. Computational protein identification searches yielded 271 and 483 protein groups in the exoproteome at pH 7.4 and pH 5.0, respectively, with 180 common proteins between both conditions. The total amount and diversity of proteins released by parasites almost doubled upon acidic incubation compared to control. Overall, 76.5% of proteins were predicted to be secreted by classical or non-classical pathways and 35.1% of these proteins have predicted transmembrane domains. Classical secretory pathway analysis showed an increased number of mucins and mucin-associated surface proteins after acidic incubation. However, the number of released trans-sialidases and surface GP63 peptidases was higher at pH 7.4. Trans-sialidases and mucins are anchored to the membrane and exhibit an enzyme-substrate relationship. In general, mucins are glycoproteins with immunomodulatory functions in Chagas disease, present mainly in the epimastigote and trypomastigote surfaces and could be enzymatically cleaved and released in the phagolysosome during amastigogenesis. Moreover, evidence for flagella discard during amastigogenesis are addressed. This study provides the first comparative analysis of the exoproteome during amastigogenesis, and the presented data evidence the dynamism of its profile in response to acidic pH-induced differentiation.
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Affiliation(s)
- Samuel C. Mandacaru
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
| | - Rayner M. L. Queiroz
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Marcos R. Alborghetti
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
| | - Lucas S. de Oliveira
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
| | - Consuelo M. R. de Lima
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
| | - Izabela M. D. Bastos
- Pathogen-Host Interface Laboratory, Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
| | - Jaime M. Santana
- Pathogen-Host Interface Laboratory, Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
| | - Peter Roepstorff
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Carlos André O. Ricart
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
| | - Sébastien Charneau
- Laboratory of Protein Chemistry and Biochemistry, Department of Cell Biology, Institute of Biology, University of Brasilia, Brasilia, Brazil
- * E-mail:
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17
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Sinclair AN, de Graffenried CL. More than Microtubules: The Structure and Function of the Subpellicular Array in Trypanosomatids. Trends Parasitol 2019; 35:760-777. [PMID: 31471215 PMCID: PMC6783356 DOI: 10.1016/j.pt.2019.07.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 10/26/2022]
Abstract
The subpellicular microtubule array defines the wide range of cellular morphologies found in parasitic kinetoplastids (trypanosomatids). Morphological studies have characterized array organization, but little progress has been made towards identifying the molecular mechanisms that are responsible for array differentiation during the trypanosomatid life cycle, or the apparent stability and longevity of array microtubules. In this review, we outline what is known about the structure and biogenesis of the array, with emphasis on Trypanosoma brucei, Trypanosoma cruzi, and Leishmania, which cause life-threatening diseases in humans and livestock. We highlight unanswered questions about this remarkable cellular structure that merit new consideration in light of our recently improved understanding of how the 'tubulin code' influences microtubule dynamics to generate complex cellular structures.
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Affiliation(s)
- Amy N Sinclair
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA
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18
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Abstract
Trypanosomes have complex life cycles within which there are both proliferative and differentiation cell divisions. The coordination of the cell cycle to achieve these different divisions is critical for the parasite to infect both host and vector. From studying the regulation of the proliferative cell cycle of the Trypanosoma brucei procyclic life cycle stage, three subcycles emerge that control the duplication and segregation of ( a) the nucleus, ( b) the kinetoplast, and ( c) a set of cytoskeletal structures. We discuss how the clear dependency relationships within these subcycles, and the potential for cross talk between them, are likely required for overall cell cycle coordination. Finally, we look at the implications this interdependence has for proliferative and differentiation divisions through the T. brucei life cycle and in related parasitic trypanosomatid species.
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Affiliation(s)
- Richard J. Wheeler
- Nuffield Department of Medicine, University of Oxford, Oxford OX1 3SY, United Kingdom
| | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Jack D. Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
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19
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Abeywickrema M, Vachova H, Farr H, Mohr T, Wheeler RJ, Lai DH, Vaughan S, Gull K, Sunter JD, Varga V. Non-equivalence in old- and new-flagellum daughter cells of a proliferative division in Trypanosoma brucei. Mol Microbiol 2019; 112:1024-1040. [PMID: 31286583 PMCID: PMC6771564 DOI: 10.1111/mmi.14345] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/03/2019] [Indexed: 12/15/2022]
Abstract
Differentiation of Trypanosoma brucei, a flagellated protozoan parasite, between life cycle stages typically occurs through an asymmetric cell division process, producing two morphologically distinct daughter cells. Conversely, proliferative cell divisions produce two daughter cells, which look similar but are not identical. To examine in detail differences between the daughter cells of a proliferative division of procyclic T. brucei we used the recently identified constituents of the flagella connector. These segregate asymmetrically during cytokinesis allowing the new‐flagellum and the old‐flagellum daughters to be distinguished. We discovered that there are distinct morphological differences between the two daughters, with the new‐flagellum daughter in particular re‐modelling rapidly and extensively in early G1. This re‐modelling process involves an increase in cell body, flagellum and flagellum attachment zone length and is accompanied by architectural changes to the anterior cell end. The old‐flagellum daughter undergoes a different G1 re‐modelling, however, despite this there was no difference in G1 duration of their respective cell cycles. This work demonstrates that the two daughters of a proliferative division of T. brucei are non‐equivalent and enables more refined morphological analysis of mutant phenotypes. We suggest all proliferative divisions in T. brucei and related organisms will involve non‐equivalence.
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Affiliation(s)
- Movin Abeywickrema
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Hana Vachova
- Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Helen Farr
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Timm Mohr
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Richard J Wheeler
- Peter Medawar Building for Pathogen Research, Nuffield Department of Medicine, University of Oxford, Oxford, OX1 3SY, UK
| | - De-Hua Lai
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, P.R. China
| | - Sue Vaughan
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Jack D Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Vladimir Varga
- Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
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20
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Lobo M, Balouz V, Melli L, Carlevaro G, Cortina ME, Cámara MDLM, Cánepa GE, Carmona SJ, Altcheh J, Campetella O, Ciocchini AE, Agüero F, Mucci J, Buscaglia CA. Molecular and antigenic characterization of Trypanosoma cruzi TolT proteins. PLoS Negl Trop Dis 2019; 13:e0007245. [PMID: 30870417 PMCID: PMC6435186 DOI: 10.1371/journal.pntd.0007245] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 03/26/2019] [Accepted: 02/14/2019] [Indexed: 01/02/2023] Open
Abstract
Background TolT was originally described as a Trypanosoma cruzi molecule that accumulated on the trypomastigote flagellum bearing similarity to bacterial TolA colicins receptors. Preliminary biochemical studies indicated that TolT resolved in SDS-PAGE as ~3–5 different bands with sizes between 34 and 45 kDa, and that this heterogeneity could be ascribed to differences in polypeptide glycosylation. However, the recurrent identification of TolT-deduced peptides, and variations thereof, in trypomastigote proteomic surveys suggested an intrinsic TolT complexity, and prompted us to undertake a thorough reassessment of this antigen. Methods/Principle findings Genome mining exercises showed that TolT constitutes a larger-than-expected family of genes, with at least 12 polymorphic members in the T. cruzi CL Brener reference strain and homologs in different trypanosomes. According to structural features, TolT deduced proteins could be split into three robust groups, termed TolT-A, TolT-B, and TolT-C, all of them showing marginal sequence similarity to bacterial TolA proteins and canonical signatures of surface localization/membrane association, most of which were herein experimentally validated. Further biochemical and microscopy-based characterizations indicated that this grouping may have a functional correlate, as TolT-A, TolT-B and TolT-C molecules showed differences in their expression profile, sub-cellular distribution, post-translational modification(s) and antigenic structure. We finally used a recently developed fluorescence magnetic beads immunoassay to validate a recombinant protein spanning the central and mature region of a TolT-B deduced molecule for Chagas disease serodiagnosis. Conclusion/Significance This study unveiled an unexpected genetic and biochemical complexity within the TolT family, which could be exploited for the development of novel T. cruzi biomarkers with diagnostic/therapeutic applications. Chagas disease, caused by the protozoan Trypanosoma cruzi, is a lifelong and debilitating neglected illness of major significance in Latin America, for which no vaccine or adequate drugs are yet available. Identification of novel biomarkers able to transcend the current limits of diagnostic and/or therapeutic assessment methods hence surfaces as a main priority in Chagas disease applied research. In this framework, we herein undertook a thorough biochemical and antigenic characterization of T. cruzi TolT surface antigens. Our results unveil an unexpected complexity within this family, with at least 12 polymorphic TolT genes in the T. cruzi CL Brener reference strain genome. According to structural features, TolT deduced molecules could be split into three robust groups that show differences in their structural features, expression profile, sub-cellular distribution, post-translational modification(s) and antigenic structure. Overall, we show that TolT molecules are conspicuously expressed by both major mammal-dwelling stages of the parasite, and that they are differentially recognized by the immune system in Chagasic patients and in T. cruzi-infected mammals. Our findings are discussed in terms of the evolution and possible structural/functional roles of TolT molecules, as well as in terms of their applicability in Chagas disease serodiagnosis.
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Affiliation(s)
- Maite Lobo
- Instituto de Investigaciones Biotecnológicas “Dr Rodolfo Ugalde” (IIB-INTECh, Universidad Nacional de San Martín and CONICET), Buenos Aires, Argentina
| | - Virginia Balouz
- Instituto de Investigaciones Biotecnológicas “Dr Rodolfo Ugalde” (IIB-INTECh, Universidad Nacional de San Martín and CONICET), Buenos Aires, Argentina
| | - Luciano Melli
- Instituto de Investigaciones Biotecnológicas “Dr Rodolfo Ugalde” (IIB-INTECh, Universidad Nacional de San Martín and CONICET), Buenos Aires, Argentina
| | - Giannina Carlevaro
- Instituto de Investigaciones Biotecnológicas “Dr Rodolfo Ugalde” (IIB-INTECh, Universidad Nacional de San Martín and CONICET), Buenos Aires, Argentina
| | - María E. Cortina
- Instituto de Investigaciones Biotecnológicas “Dr Rodolfo Ugalde” (IIB-INTECh, Universidad Nacional de San Martín and CONICET), Buenos Aires, Argentina
| | - María de los Milagros Cámara
- Instituto de Investigaciones Biotecnológicas “Dr Rodolfo Ugalde” (IIB-INTECh, Universidad Nacional de San Martín and CONICET), Buenos Aires, Argentina
| | - Gaspar E. Cánepa
- Instituto de Investigaciones Biotecnológicas “Dr Rodolfo Ugalde” (IIB-INTECh, Universidad Nacional de San Martín and CONICET), Buenos Aires, Argentina
| | - Santiago J. Carmona
- Instituto de Investigaciones Biotecnológicas “Dr Rodolfo Ugalde” (IIB-INTECh, Universidad Nacional de San Martín and CONICET), Buenos Aires, Argentina
| | - Jaime Altcheh
- Servicio de Parasitología-Chagas, Hospital de Niños Ricardo Gutiérrez, Buenos Aires, Argentina
| | - Oscar Campetella
- Instituto de Investigaciones Biotecnológicas “Dr Rodolfo Ugalde” (IIB-INTECh, Universidad Nacional de San Martín and CONICET), Buenos Aires, Argentina
| | - Andrés E. Ciocchini
- Instituto de Investigaciones Biotecnológicas “Dr Rodolfo Ugalde” (IIB-INTECh, Universidad Nacional de San Martín and CONICET), Buenos Aires, Argentina
| | - Fernán Agüero
- Instituto de Investigaciones Biotecnológicas “Dr Rodolfo Ugalde” (IIB-INTECh, Universidad Nacional de San Martín and CONICET), Buenos Aires, Argentina
| | - Juan Mucci
- Instituto de Investigaciones Biotecnológicas “Dr Rodolfo Ugalde” (IIB-INTECh, Universidad Nacional de San Martín and CONICET), Buenos Aires, Argentina
- * E-mail: (JM); (CAB)
| | - Carlos A. Buscaglia
- Instituto de Investigaciones Biotecnológicas “Dr Rodolfo Ugalde” (IIB-INTECh, Universidad Nacional de San Martín and CONICET), Buenos Aires, Argentina
- * E-mail: (JM); (CAB)
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21
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Pack AD, Collins MH, Rosenberg CS, Tarleton RL. Highly competent, non-exhausted CD8+ T cells continue to tightly control pathogen load throughout chronic Trypanosoma cruzi infection. PLoS Pathog 2018; 14:e1007410. [PMID: 30419010 PMCID: PMC6258465 DOI: 10.1371/journal.ppat.1007410] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 11/26/2018] [Accepted: 10/17/2018] [Indexed: 12/21/2022] Open
Abstract
Trypanosoma cruzi infection is characterized by chronic parasitism of non-lymphoid tissues and is rarely eliminated despite potent adaptive immune responses. This failure to cure has frequently been attributed to a loss or impairment of anti-T. cruzi T cell responses over time, analogous to the T cell dysfunction described for other persistent infections. In this study, we have evaluated the role of CD8+ T cells during chronic T. cruzi infection (>100 dpi), with a focus on sites of pathogen persistence. Consistent with repetitive antigen exposure during chronic infection, parasite-specific CD8+ T cells from multiple organs expressed high levels of KLRG1, but exhibit a preferential accumulation of CD69+ cells in skeletal muscle, indicating recent antigen encounter in a niche for T. cruzi persistence. A significant proportion of CD8+ T cells in the muscle also produced IFNγ, TNFα and granzyme B in situ, an indication of their detection of and functional response to T. cruzi in vivo. CD8+ T cell function was crucial for the control of parasite burden during chronic infection as exacerbation of parasite load was observed upon depletion of this population. Attempts to improve T cell function by blocking PD-1 or IL-10, potential negative regulators of T cells, failed to increase IFNγ and TNFα production or to enhance T. cruzi clearance. These results highlight the capacity of the CD8+ T cell population to retain essential in vivo function despite chronic antigen stimulation and support a model in which CD8+ T cell dysfunction plays a negligible role in the ability of Trypanosoma cruzi to persist in mice. The parasite Trypanosoma cruzi establishes lifelong infections in humans and other mammals, leading to severe cardiac and gastrointestinal complications known as Chagas disease. Although the factors that enable T. cruzi persistence remain undefined, in this and many other infection models, pathogen persistence has been attributed to the exhaustion of the immune system, particularly of CD8+ T cells. Here, we show that the inability of hosts to fully resolve T. cruzi infection is not a result of immune exhaustion and that in fact the T. cruzi-specific CD8+ T cell population remains highly competent and actively suppresses parasite outgrowth throughout the chronic infection. These results demonstrate that compromised immunity is not the eventual outcome of all chronic infections and suggest that T. cruzi, and perhaps other pathogens, may employ alternative strategies to subvert immune clearance in the presence of highly functional pathogen-specific effectors. These findings also suggest that interventions to inhibit immune regulatory pathways or to otherwise boost existing immune responses in such infections, will have limited benefit.
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Affiliation(s)
- Angela D. Pack
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Matthew H. Collins
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
| | - Charles S. Rosenberg
- Department of Microbiology, University of Georgia, Athens, Georgia, United States of America
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Rick L. Tarleton
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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22
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Borges AR, Toledo DA, Fermino BR, de Oliveira JC, Silber AM, Elias MC, D'Avila H, Scopel KKG. In Vitro Cellular Division of Trypanosoma abeli Reveals Two Pathways for Organelle Replication. J Eukaryot Microbiol 2018; 66:385-392. [PMID: 30076737 DOI: 10.1111/jeu.12678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 07/07/2018] [Accepted: 07/22/2018] [Indexed: 11/28/2022]
Abstract
Since the observation of the great pleomorphism of fish trypanosomes, in vitro culture has become an important tool to support taxonomic studies investigating the biology of cultured parasites, such as their structure, growth dynamics, and cellular cycle. Relative to their biology, ex vivo and in vitro studies have shown that these parasites, during the multiplication process, duplicate and segregate the kinetoplast before nucleus replication and division. However, the inverse sequence (the nucleus divides before the kinetoplast) has only been documented for a species of marine fish trypanosomes on a single occasion. Now, this previously rare event was observed in Trypanosoma abeli, a freshwater fish trypanosome. Specifically, from 376 cultured parasites in the multiplication process, we determined the sequence of organelle division for 111 forms; 39% exhibited nucleus duplication prior to kinetoplast replication. Thus, our results suggest that nucleus division before the kinetoplast may not represent an accidental or erroneous event occurring in the main pathway of parasite reproduction, but instead could be a species-specific process of cell biology in trypanosomes, such as previously noticed for Leishmania. This "alternative" pathway for organelle replication is a new field to be explored concerning the biology of marine and freshwater fish trypanosomes.
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Affiliation(s)
- Alyssa R Borges
- Laboratory of Parasitology, Department of Parasitology, Microbiology and Immunology, Institute of Biological Sciences, Federal University of Juiz de Fora, Rua José Lourenço Kelmer s/n - Campus Universitário, São Pedro, Juiz de Fora, MG, 36036-900, Brazil
| | - Daniel A Toledo
- Laboratory of Cellular Biology, Department of Biology, Institute of Biological Sciences, Federal University of Juiz de Fora, Rua José Lourenço Kelmer s/n - Campus Universitário, São Pedro, Juiz de Fora, MG, 36036-900, Brazil
| | - Bruno R Fermino
- Department of Parasitology, Institute of Biomedical Sciences, São Paulo University, Av. Prof. Lineu Prestes 1374 - Cidade Universitária, São Paulo, SP, 05508-900, Brazil
| | - José Carlos de Oliveira
- Department of Zoology, Institute of Biological Sciences, Federal University of Juiz de Fora, Rua José Lourenço Kelmer s/n - Campus Universitário, São Pedro, Juiz de Fora, MG, 36036-900, Brazil
| | - Ariel Mariano Silber
- Laboratory of Biochemistry of Tryps - LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1374 - Cidade Universitária, São Paulo, SP, 05508-000, Brazil
| | - Maria Carolina Elias
- Laboratório Especial de Ciclo Celular, Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, Av. Vital Brasil 1500 - Butantã, São Paulo, SP, 05503-900, Brazil
| | - Heloisa D'Avila
- Laboratory of Cellular Biology, Department of Biology, Institute of Biological Sciences, Federal University of Juiz de Fora, Rua José Lourenço Kelmer s/n - Campus Universitário, São Pedro, Juiz de Fora, MG, 36036-900, Brazil
| | - Kézia K G Scopel
- Laboratory of Parasitology, Department of Parasitology, Microbiology and Immunology, Institute of Biological Sciences, Federal University of Juiz de Fora, Rua José Lourenço Kelmer s/n - Campus Universitário, São Pedro, Juiz de Fora, MG, 36036-900, Brazil
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23
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Ubiquitin Proteasome pathway proteins as potential drug targets in parasite Trypanosoma cruzi. Sci Rep 2018; 8:8399. [PMID: 29849031 PMCID: PMC5976635 DOI: 10.1038/s41598-018-26532-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/15/2018] [Indexed: 12/11/2022] Open
Abstract
Trypanosomiasis infects more than 21 million people and claims approximately 2 million lives annually. Due to the development of resistance against currently available anti-trypanosomal drugs, there is a growing need for specific inhibitors and novel drug targets. Of late, the proteins from the Ubiquitin Proteasome Pathway (UPP): ubiquitin ligases and deubiquitinase have received attention as potential drug targets in other parasites from the apicomplexan family. The completion of Trypanosoma cruzi (Tc) genome sequencing in 2005 and subsequent availability of database resources like TriTrypDB has provided a platform for the systematic study of the proteome of this parasite. Here, we present the first comprehensive survey of the UPP enzymes, their homologs and other associated proteins in trypanosomes and the UPPs from T. cruzi were explored in detail. After extensive computational analyses using various bioinformatics tools, we have identified 269 putative UPP proteins in the T. cruzi proteome along with their homologs in other Trypanosoma species. Characterization of T. cruzi proteome was done based on their predicted subcellular localization, domain architecture and overall expression profiles. Specifically, unique domain architectures of the enzymes and the UPP players expressed exclusively in the amastigote stage provide a rationale for designing inhibitors against parasite UPP proteins.
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24
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Peacock L, Kay C, Bailey M, Gibson W. Shape-shifting trypanosomes: Flagellar shortening followed by asymmetric division in Trypanosoma congolense from the tsetse proventriculus. PLoS Pathog 2018; 14:e1007043. [PMID: 29772025 PMCID: PMC5957336 DOI: 10.1371/journal.ppat.1007043] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 04/18/2018] [Indexed: 11/18/2022] Open
Abstract
Trypanosomatids such as Leishmania and Trypanosoma are digenetic, single-celled, parasitic flagellates that undergo complex life cycles involving morphological and metabolic changes to fit them for survival in different environments within their mammalian and insect hosts. According to current consensus, asymmetric division enables trypanosomatids to achieve the major morphological rearrangements associated with transition between developmental stages. Contrary to this view, here we show that the African trypanosome Trypanosoma congolense, an important livestock pathogen, undergoes extensive cell remodelling, involving shortening of the cell body and flagellum, during its transition from free-swimming proventricular forms to attached epimastigotes in vitro. Shortening of the flagellum was associated with accumulation of PFR1, a major constituent of the paraflagellar rod, in the mid-region of the flagellum where it was attached to the substrate. However, the PFR1 depot was not essential for attachment, as it accumulated several hours after initial attachment of proventricular trypanosomes. Detergent and CaCl2 treatment failed to dislodge attached parasites, demonstrating the robust nature of flagellar attachment to the substrate; the PFR1 depot was also unaffected by these treatments. Division of the remodelled proventricular trypanosome was asymmetric, producing a small daughter cell. Each mother cell went on to produce at least one more daughter cell, while the daughter trypanosomes also proliferated, eventually resulting in a dense culture of epimastigotes. Here, by observing the synchronous development of the homogeneous population of trypanosomes in the tsetse proventriculus, we have been able to examine the transition from proventricular forms to attached epimastigotes in detail in T. congolense. This transition is difficult to observe in vivo as it happens inside the mouthparts of the tsetse fly. In T. brucei, this transition is achieved by asymmetric division of long trypomastigotes in the proventriculus, yielding short epimastigotes, which go on to colonise the salivary glands. Thus, despite their close evolutionary relationship and shared developmental route within the vector, T. brucei and T. congolense have evolved different ways of accomplishing the same developmental transition from proventricular form to attached epimastigote. Tsetse-transmitted trypanosomes are parasitic protists that cause severe human and livestock diseases in tropical Africa. During their developmental cycle in the tsetse fly, these trypanosomes undergo complex cycles of differentiation and proliferation. Here we have investigated part of the developmental cycle of the major livestock pathogen Trypanosoma congolense as it moves from the fly midgut via the foregut to the mouthparts, where it reacquires infectivity to mammalian hosts. This transition is difficult to observe in vivo because of the small numbers of migratory trypanosomes and their inaccessibility in the fly. However, prior to migration, trypanosomes accumulate in the proventriculus, the valve that separates the foregut from the midgut, and we were able to observe the behaviour of these cells in vitro. On release from the proventriculus, these trypanosomes readily attach to a glass microscope slide and then undergo drastic remodelling to become short, stout cells, before each produces a small daughter cell. Each mother cell goes on to produce at least one further daughter trypanosome in the same way, while the daughter cells also proliferate as attached cells. We assume that these events would normally happen in vivo inside the tsetse proboscis. In T. brucei the equivalent developmental transition takes place in the proventriculus or foregut in free-swimming rather than attached cells, and is achieved via an asymmetric division. Thus, despite their close evolutionary relationship, these two trypanosome species have evolved different ways of accomplishing what is essentially the same developmental transition.
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Affiliation(s)
- Lori Peacock
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
- Bristol Veterinary School, University of Bristol, Langford, Bristol, United Kingdom
| | - Christopher Kay
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Mick Bailey
- Bristol Veterinary School, University of Bristol, Langford, Bristol, United Kingdom
| | - Wendy Gibson
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
- * E-mail:
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25
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Toro Acevedo CA, Valente BM, Burle-Caldas GA, Galvão-Filho B, Santiago HDC, Esteves Arantes RM, Junqueira C, Gazzinelli RT, Roffê E, Teixeira SMR. Down Modulation of Host Immune Response by Amino Acid Repeats Present in a Trypanosoma cruzi Ribosomal Antigen. Front Microbiol 2017; 8:2188. [PMID: 29176965 PMCID: PMC5686100 DOI: 10.3389/fmicb.2017.02188] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 10/25/2017] [Indexed: 12/18/2022] Open
Abstract
Several antigens from Trypanosoma cruzi, the causative agent of Chagas disease (CD), contain amino acid repeats identified as targets of the host immune response. Ribosomal proteins containing an Ala, Lys, Pro-rich repeat domain are among the T. cruzi antigens that are strongly recognized by antibodies from CD patients. Here we investigated the role of amino acid repeats present in the T. cruzi ribosomal protein L7a, by immunizing mice with recombinant versions of the full-length protein (TcRpL7a), as well as with truncated versions containing only the repetitive (TcRpL7aRep) or the non-repetitive domains (TcRpL7aΔRep). Mice immunized with full-length TcRpL7a produced high levels of IgG antibodies against the complete protein as well as against the repeat domain, whereas mice immunized with TcRpL7aΔRep or TcRpL7aRep produced very low levels or did not produce IgG antibodies against this antigen. Also in contrast to mice immunized with the full-length TcRpL7a, which produced high levels of IFN-γ, only low levels of IFN-γ or no IFN-γ were detected in cultures of splenocytes derived from mice immunized with truncated versions of the protein. After challenging with trypomastigotes, mice immunized with the TcRpL7a were partially protected against the infection whereas immunization with TcRpL7aΔRep did not alter parasitemia levels compared to controls. Strikingly, mice immunized with TcRpL7aRep displayed an exacerbated parasitemia compared to the other groups and 100% mortality after infection. Analyses of antibody production in mice that were immunized with TcRpL7aRep prior to infection showed a reduced humoral response to parasite antigens as well as against an heterologous antigen. In vitro proliferation assays with mice splenocytes incubated with different mitogens in the presence of TcRpL7aRep resulted in a drastic inhibition of B-cell proliferation and antibody production. Taken together, these results indicate that the repeat domain of TcRpL7a acts as an immunosuppressive factor that down regulates the host B-cell response against parasite antigens favoring parasite multiplication in the mammalian host.
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Affiliation(s)
- Carlos A. Toro Acevedo
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Bruna M. Valente
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Gabriela A. Burle-Caldas
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Bruno Galvão-Filho
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Helton da C. Santiago
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Rosa M. Esteves Arantes
- Departamento de Patologia Geral, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Caroline Junqueira
- Instituto de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Brazil
| | - Ricardo T. Gazzinelli
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Instituto de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Brazil
| | - Ester Roffê
- Instituto de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Brazil
| | - Santuza M. R. Teixeira
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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26
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Abstract
Chagas disease is caused by infection with the insect-transmitted protozoan Trypanosoma cruzi, and is the most important parasitic infection in Latin America. The current drugs, benznidazole and nifurtimox, are characterized by limited efficacy and toxic side-effects, and treatment failures are frequently observed. The urgent need for new therapeutic approaches is being met by a combined effort from the academic and commercial sectors, together with major input from not-for-profit drug development consortia. With the disappointing outcomes of recent clinical trials against chronic Chagas disease, it has become clear that an incomplete understanding of parasite biology and disease pathogenesis is impacting negatively on the development of more effective drugs. In addition, technical issues, including difficulties in establishing parasitological cure in both human patients and animal models, have greatly complicated the assessment of drug efficacy. Here, we outline the major questions that need to be addressed and discuss technical innovations that can be exploited to accelerate the drug development pipeline.
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27
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Kessler RL, Contreras VT, Marliére NP, Aparecida Guarneri A, Villamizar Silva LH, Mazzarotto GACA, Batista M, Soccol VT, Krieger MA, Probst CM. Recently differentiated epimastigotes fromTrypanosoma cruziare infective to the mammalian host. Mol Microbiol 2017; 104:712-736. [DOI: 10.1111/mmi.13653] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2017] [Indexed: 12/31/2022]
Affiliation(s)
| | - Víctor Tulio Contreras
- Laboratorio de Protozoología, Centro de Biología Molecular de Parásitos, Facultad Ciencias de la Salud; Universidad de Carabobo; Valencia Venezuela
| | - Newmar Pinto Marliére
- Vector Behavior and Pathogen Interaction Group; Centro de Pesquisas René Rachou, Fiocruz; Belo Horizonte Minas Gerais Brazil
| | - Alessandra Aparecida Guarneri
- Vector Behavior and Pathogen Interaction Group; Centro de Pesquisas René Rachou, Fiocruz; Belo Horizonte Minas Gerais Brazil
| | | | | | | | - Vanete Thomaz Soccol
- Programa de Pós-Graduação em Processos Biotecnológicos e Biotecnologia, Centro Politécnico; Universidade Federal do Paraná; Curitiba PR Brazil
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28
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Engineered trivalent immunogen adjuvanted with a STING agonist confers protection against Trypanosoma cruzi infection. NPJ Vaccines 2017; 2:9. [PMID: 29263868 PMCID: PMC5604744 DOI: 10.1038/s41541-017-0010-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 02/01/2017] [Accepted: 02/10/2017] [Indexed: 11/17/2022] Open
Abstract
The parasite Trypanosoma cruzi is the causative agent of Chagas disease, a potentially life-threatening infection that represents a major health problem in Latin America. Several characteristics of this protozoan contribute to the lack of an effective vaccine, among them: its silent invasion mechanism, T. cruzi antigen redundancy and immunodominance without protection. Taking into account these issues, we engineered Traspain, a chimeric antigen tailored to present a multivalent display of domains from key parasitic molecules, combined with stimulation of the STING pathway by c-di-AMP as a novel prophylactic strategy. This formulation proved to be effective for the priming of functional humoral responses and pathogen-specific CD8+ and CD4+ T cells, compatible with a Th1/Th17 bias. Interestingly, vaccine effectiveness assessed across the course of infection, showed a reduction in parasite load and chronic inflammation in different proof of concept assays. In conclusion, this approach represents a promising tool against parasitic chronic infections. An amalgamation of parasitic proteins may be the first effective vaccine against the as yet untreatable chronic phase of Chagas disease. The infliction, caused by the parasite Trypanosoma cruzi (T. cruzi), is the world’s leading cause of infectious cardiac inflammation and puts one-sixth of the population of Latin America at risk of infection. International collaborators led by Emilio Malchiodi, of the University of Buenos Aires, Argentina, constructed a vaccine (dubbed ‘Traspain’) comprised of key T. cruzi proteins alongside a novel ‘adjuvant’—designed to promote the efficacy of a vaccine by activating inflammatory responses. The chimera and adjuvant combination elicited a promising immune response and also showed the capacity to prevent tissue damage caused by chronic infection. Multi-part vaccines such as Traspain offer an attractive direction for research into vaccines against chronic parasitic infections.
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29
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Ooi CP, Schuster S, Cren-Travaillé C, Bertiaux E, Cosson A, Goyard S, Perrot S, Rotureau B. The Cyclical Development of Trypanosoma vivax in the Tsetse Fly Involves an Asymmetric Division. Front Cell Infect Microbiol 2016; 6:115. [PMID: 27734008 PMCID: PMC5039179 DOI: 10.3389/fcimb.2016.00115] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/12/2016] [Indexed: 11/15/2022] Open
Abstract
Trypanosoma vivax is the most prevalent trypanosome species in African cattle. It is thought to be transmitted by tsetse flies after cyclical development restricted to the vector mouthparts. Here, we investigated the kinetics of T. vivax development in Glossina morsitans morsitans by serial dissections over 1 week to reveal differentiation and proliferation stages. After 3 days, stable numbers of attached epimastigotes were seen proliferating by symmetric division in the cibarium and proboscis, consistent with colonization and maintenance of a parasite population for the remaining lifespan of the tsetse fly. Strikingly, some asymmetrically dividing cells were also observed in proportions compatible with a continuous production of pre- metacyclic trypomastigotes. The involvement of this asymmetric division in T. vivax metacyclogenesis is discussed and compared to other trypanosomatids.
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Affiliation(s)
- Cher-Pheng Ooi
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors, Institut Pasteur and INSERM U1201 Paris, France
| | - Sarah Schuster
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors, Institut Pasteur and INSERM U1201 Paris, France
| | - Christelle Cren-Travaillé
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors, Institut Pasteur and INSERM U1201 Paris, France
| | - Eloise Bertiaux
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors, Institut Pasteur and INSERM U1201 Paris, France
| | - Alain Cosson
- Trypanosomatids Infectious Processes Unit, Department of Infection and Epidemiology, Institut Pasteur Paris, France
| | - Sophie Goyard
- Trypanosomatids Infectious Processes Unit, Department of Infection and Epidemiology, Institut Pasteur Paris, France
| | - Sylvie Perrot
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors, Institut Pasteur and INSERM U1201 Paris, France
| | - Brice Rotureau
- Trypanosome Transmission Group, Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors, Institut Pasteur and INSERM U1201 Paris, France
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30
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Weatherly DB, Peng D, Tarleton RL. Recombination-driven generation of the largest pathogen repository of antigen variants in the protozoan Trypanosoma cruzi. BMC Genomics 2016; 17:729. [PMID: 27619017 PMCID: PMC5020489 DOI: 10.1186/s12864-016-3037-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 08/24/2016] [Indexed: 12/15/2022] Open
Abstract
Background The protozoan parasite Trypanosoma cruzi, causative agent of Chagas disease, depends upon a cell surface-expressed trans-sialidase (ts) to avoid activation of complement-mediated lysis and to enhance intracellular invasion. However these functions alone fail to account for the size of this gene family in T. cruzi, especially considering that most of these genes encode proteins lacking ts enzyme activity. Previous whole genome sequencing of the CL Brener clone of T. cruzi identified ~1400 ts variants, but left many partially assembled sequences unannotated. Results In the current study we reevaluated the trans-sialidase-like sequences in this reference strain, identifying an additional 1779 full-length and partial ts genes with their important features annotated, and confirming the expression of previously annotated “pseudogenes” and newly annotated ts family members. Multiple EM for Motif Elicitation (MEME) analysis allowed us to generate a model T. cruzi ts (TcTS) based upon the most conserved motif patterns and demonstrated that a common motif order is highly conserved among ts family members. Using a newly developed pipeline for the analysis of recombination within large gene families, we further demonstrate that TcTS family members are undergoing frequent recombination, generating new variants from the thousands of functional and non-functional ts gene segments but retaining the overall structure of the core TcTS family members. Conclusions The number and variety as well as high recombination frequency of TcTS family members supports strong evolutionary pressure, probably exerted by immune selection, for continued variation in ts sequences in T. cruzi, and thus for a unique immune evasion mechanism for the large ts gene family. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3037-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- D Brent Weatherly
- Center for Tropical and Emerging Global Diseases, Institute of Bioinformatics and Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA.,Center for Complex Carbohydrate Research, University of Georgia, Athens, GA, 30602, USA
| | - Duo Peng
- Center for Tropical and Emerging Global Diseases, Institute of Bioinformatics and Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA
| | - Rick L Tarleton
- Center for Tropical and Emerging Global Diseases, Institute of Bioinformatics and Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA.
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31
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Long-Term Immunity to Trypanosoma cruzi in the Absence of Immunodominant trans-Sialidase-Specific CD8+ T Cells. Infect Immun 2016; 84:2627-38. [PMID: 27354447 DOI: 10.1128/iai.00241-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 06/24/2016] [Indexed: 11/20/2022] Open
Abstract
Trypanosoma cruzi infection drives the expansion of remarkably focused CD8(+) T cell responses targeting epitopes encoded by variant trans-sialidase (TS) genes. Infection of C57BL/6 mice with T. cruzi results in up to 40% of all CD8(+) T cells committed to recognition of the dominant TSKB20 and subdominant TSKB18 TS epitopes. However, despite this enormous response, these mice fail to clear T. cruzi infection and subsequently develop chronic disease. One possible reason for the failure to cure T. cruzi infection is that immunodomination by these TS-specific T cells may interfere with alternative CD8(+) T cell responses more capable of complete parasite elimination. To address this possibility, we created transgenic mice that are centrally tolerant to these immunodominant epitopes. Mice expressing TSKB20, TSKB18, or both epitopes controlled T. cruzi infection and developed effector CD8(+) T cells that maintained an activated phenotype. Memory CD8(+) T cells from drug-cured TSKB-transgenic mice rapidly responded to secondary T. cruzi infection. In the absence of the response to TSKB20 and TSKB18, immunodominance did not shift to other known subdominant epitopes despite the capacity of these mice to expand epitope-specific T cells specific for the model antigen ovalbumin expressed by engineered parasites. Thus, CD8(+) T cell responses tightly and robustly focused on a few epitopes within variant TS antigens appear to neither contribute to, nor detract from, the ability to control T. cruzi infection. These data also indicate that the relative position of an epitope within a CD8(+) immunodominance hierarchy does not predict its importance in pathogen control.
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Chagas Disease: A Solvable Problem, Ignored. Trends Mol Med 2016; 22:835-838. [PMID: 27523778 DOI: 10.1016/j.molmed.2016.07.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/22/2016] [Accepted: 07/22/2016] [Indexed: 01/16/2023]
Abstract
Chagas disease is the highest impact parasitic disease in the Americas, yet remains virtually unknown and untreated, despite the fact that the infection is curable and the global problem of Chagas disease is manageable. The causes of this situation and how it can be changed are the focus of this communication.
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Basal body multipotency and axonemal remodelling are two pathways to a 9+0 flagellum. Nat Commun 2015; 6:8964. [PMID: 26667778 PMCID: PMC4682162 DOI: 10.1038/ncomms9964] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 10/21/2015] [Indexed: 02/07/2023] Open
Abstract
Eukaryotic cilia/flagella exhibit two characteristic ultrastructures reflecting two main functions; a 9+2 axoneme for motility and a 9+0 axoneme for sensation and signalling. Whether, and if so how, they interconvert is unclear. Here we analyse flagellum length, structure and molecular composition changes in the unicellular eukaryotic parasite Leishmania during the transformation of a life cycle stage with a 9+2 axoneme (the promastigote) to one with a 9+0 axoneme (the amastigote). We show 9+0 axonemes can be generated by two pathways: by de novo formation and by restructuring of existing 9+2 axonemes associated with decreased intraflagellar transport. Furthermore, pro-basal bodies formed under conditions conducive for 9+2 axoneme formation can form a 9+0 axoneme de novo. We conclude that pro-centrioles/pro-basal bodies are multipotent and not committed to form either a 9+2 or 9+0 axoneme. In an alternative pathway structures can also be removed from existing 9+2 axonemes to convert them to 9+0. Whether basal bodies are pre-committed to form 9+2 motile or 9+0 sensory axonemes and whether interconversion occurs between the two types of axonemes is not clear. Here, the authors used the unicellular eukaryote Leishmania as a model system to demonstrate that 9+0 axonemes can be formed de novo or by restructuring of 9+2 axonemes.
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Lost but not forgotten. Cell Host Microbe 2015; 16:423-5. [PMID: 25299325 DOI: 10.1016/j.chom.2014.09.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
During its developmental transformation in the mammalian host, Trypanosma cruzi discards it flagellum into the cytoplasm of the host cell. In the current issue of Cell Host & Microbe, Kurup and Tarleton (2014) exploit the antigens made available by this process to develop a more effective vaccine strategy.
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Abstract
Trypanosoma cruzi infection and Chagas disease remains among the most neglected of the neglected tropical diseases. Despite this, studies of the immune response to T. cruzi have provided new insights in immunology and guidance for approaches for prevention and treatment of the disease. T. cruzi represents one of the very best systems in which to study CD8(+) T cell biology; mice, dogs, and primates (and many other mammals) are all natural hosts for this parasite, the robust T cell responses generated in these hosts can be readily monitored using the full range of cutting edge techniques, and the parasite can be easily modified to express (or not) a variety of tags, reporters, immune enhances, and endogenous or model antigens. The infection in most hosts is characterized by vigorous and largely effective immune responses, including CD8(+) T cells capable of controlling T. cruzi at the level of the infected host cells. However, this immune control is only partially effective and most hosts maintain a low level infection for life. This review addresses the interplay of highly effective CD8(+) T cell responses with elaborate pathogen immune evasion mechanisms, including the generation and simultaneous expression of highly variant CD8(+) T cell targets and a host cell invasion mechanisms that largely eludes innate immune detection.
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Affiliation(s)
- Rick L Tarleton
- Center for Tropical and Emerging Global Diseases and Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA,
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Bustamante J, Tarleton R. Reaching for the Holy Grail: insights from infection/cure models on the prospects for vaccines for Trypanosoma cruzi infection. Mem Inst Oswaldo Cruz 2015; 110:445-51. [PMID: 25946159 PMCID: PMC4489482 DOI: 10.1590/0074-02760140440] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 02/25/2015] [Indexed: 11/21/2022] Open
Abstract
Prevention of Trypanosoma cruzi infection in mammals likely depends
on either prevention of the invading trypomastigotes from infecting host cells or the
rapid recognition and killing of the newly infected cells by T.
cruzi-specific T cells. We show here that multiple rounds of infection
and cure (by drug therapy) fails to protect mice from reinfection, despite the
generation of potent T cell responses. This disappointing result is similar to that
obtained with many other vaccine protocols used in attempts to protect animals
from T. cruzi infection. We have previously shown that immune
recognition of T. cruzi infection is significantly delayed both at
the systemic level and at the level of the infected host cell. The systemic delay
appears to be the result of a stealth infection process that fails to trigger
substantial innate recognition mechanisms while the delay at the cellular level is
related to the immunodominance of highly variable gene family proteins, in particular
those of the trans-sialidase family. Here we discuss how these previous studies and
the new findings herein impact our thoughts on the potential of prophylactic
vaccination to serve a productive role in the prevention of T. cruzi
infection and Chagas disease.
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Affiliation(s)
- Juan Bustamante
- Centro de Investigación en Salud Internacional de Barcelona, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Rick Tarleton
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
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Benmerah A, Durand B, Giles RH, Harris T, Kohl L, Laclef C, Meilhac SM, Mitchison HM, Pedersen LB, Roepman R, Swoboda P, Ueffing M, Bastin P. The more we know, the more we have to discover: an exciting future for understanding cilia and ciliopathies. Cilia 2015; 4:5. [PMID: 25974046 PMCID: PMC4378380 DOI: 10.1186/s13630-015-0014-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 02/23/2015] [Indexed: 11/10/2022] Open
Abstract
The Cilia 2014 conference was organised by four European networks: the Ciliopathy Alliance, the Groupement de Recherche CIL, the Nordic Cilia and Centrosome Network and the EU FP7 programme SYSCILIA. More than 400 delegates from 27 countries gathered at the Institut Pasteur conference centre in Paris, including 30 patients and patient representatives. The meeting offered a unique opportunity for exchange between different scientific and medical communities. Major highlights included new discoveries about the roles of motile and immotile cilia during development and homeostasis, the mechanism of cilium construction, as well as progress in diagnosis and possible treatment of ciliopathies. The contributions to the cilia field of flagellated infectious eukaryotes and of systems biology were also presented.
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Affiliation(s)
- Alexandre Benmerah
- INSERM U1163, Laboratoire des Maladies Rénales Héréditaires, 24 boulevard du Montparnasse, 75015 Paris, France ; Institut Imagine, Université Paris Descartes-Sorbonne Paris Cité, 24 boulevard du Montparnasse, 75015 Paris, France
| | - Bénédicte Durand
- Centre de Génétique et de Physiologie Moléculaires et Cellulaires, CNRS UMR 5534, Université Claude Bernard Lyon 1, 16 rue Dubois, Villeurbanne, Lyon, F69622 France
| | - Rachel H Giles
- Department of Nephrology, University Medical Centre Utrecht, 100 Heidelberglaan, Utrecht, 3584CX The Netherlands
| | - Tess Harris
- The Ciliopathy Alliance, 91 Royal College St, NW1 0SE, London
| | - Linda Kohl
- UMR7245 CNRS/MNHN, Muséum National d'Histoire Naturelle, 57 rue Cuvier, 75005 Paris, France
| | - Christine Laclef
- Developmental Biology Laboratory UMR7622, UPMC Univ Paris 06, Sorbonne Université, 9 Quai Saint Bernard, F-75005 Paris, France ; Developmental Biology Laboratory UMR7622, CNRS, Institut de Biologie Paris Seine (IBPS), 9 Quai Saint Bernard, F-75005 Paris, France ; INSERM, ERL1156, 9 Quai Saint Bernard, F-75005 Paris, France
| | - Sigolène M Meilhac
- Department of Developmental and Stem Cell Biology, Institut Pasteur, 25 rue du docteur Roux, 75015 Paris, France ; CNRS URA2578, 25 rue du docteur Roux, 75015 Paris, France
| | - Hannah M Mitchison
- Genetics and Genomic Medicine, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH UK
| | - Lotte B Pedersen
- Department of Biology, University of Copenhagen, Universitetsparken 13, 2100 Copenhagen, OE Denmark
| | - Ronald Roepman
- Department of Human Genetics, Radboud University Medical Center, Geert Grooteplein 25, P.O. Box 9101, 6525 Nijmegen, GA The Netherlands
| | - Peter Swoboda
- Department of Biosciences and Nutrition, Karolinska Institute, Hälsovägen 7, S-141 83 Huddinge, Sweden
| | - Marius Ueffing
- Institute for Ophthalmic Research, University of Tübingen, PO 2669, D-72016 Tübingen, Germany ; Research Unit of Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health, D-85758 Neuherberg, Germany
| | - Philippe Bastin
- Trypanosome Cell Biology Unit, Institut Pasteur and INSERM U1201, 25 rue du Docteur Roux, 75015 Paris, France
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