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Ramachandran A, Sharma A. Dissecting the mechanisms of pathogenesis in cerebral malaria. PLoS Pathog 2022; 18:e1010919. [PMCID: PMC9671333 DOI: 10.1371/journal.ppat.1010919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Cerebral malaria (CM) is one of the leading causes of death due to malaria. It is characterised by coma, presence of asexual parasites in blood smear, and absence of any other reason that can cause encephalopathy. The fatality rate for CM is high, and those who survive CM often experience long-term sequelae, including cognitive and motor dysfunctions. It is unclear how parasites sequestered in the lumen of endothelial cells of the blood–brain barrier (BBB), and localised breakdown of BBB can manifest gross physiological changes across the brain. The pathological changes associated with CM are mainly due to the dysregulation of inflammatory and coagulation pathways. Other factors like host and parasite genetics, transmission intensity, and the host’s immune status are likely to play a role in the development and progression of CM. This work focuses on the pathological mechanisms underlying CM. Insights from humans, mice, and in vitro studies have been summarised to present a cohesive understanding of molecular mechanisms involved in CM pathology.
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Affiliation(s)
- Arathy Ramachandran
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Amit Sharma
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- * E-mail:
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2
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Ruberto AA, Maher SP, Vantaux A, Joyner CJ, Bourke C, Balan B, Jex A, Mueller I, Witkowski B, Kyle DE. Single-cell RNA profiling of Plasmodium vivax-infected hepatocytes reveals parasite- and host- specific transcriptomic signatures and therapeutic targets. Front Cell Infect Microbiol 2022; 12:986314. [PMID: 36093191 PMCID: PMC9453201 DOI: 10.3389/fcimb.2022.986314] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 08/08/2022] [Indexed: 12/12/2022] Open
Abstract
The resilience of Plasmodium vivax, the most widely-distributed malaria-causing parasite in humans, is attributed to its ability to produce dormant liver forms known as hypnozoites, which can activate weeks, months, or even years after an initial mosquito bite. The factors underlying hypnozoite formation and activation are poorly understood, as is the parasite's influence on the host hepatocyte. Here, we shed light on transcriptome-wide signatures of both the parasite and the infected host cell by sequencing over 1,000 P. vivax-infected hepatocytes at single-cell resolution. We distinguish between replicating schizonts and hypnozoites at the transcriptional level, identifying key differences in transcripts encoding for RNA-binding proteins associated with cell fate. In infected hepatocytes, we show that genes associated with energy metabolism and antioxidant stress response are upregulated, and those involved in the host immune response downregulated, suggesting both schizonts and hypnozoites alter the host intracellular environment. The transcriptional markers in schizonts, hypnozoites, and infected hepatocytes revealed here pinpoint potential factors underlying dormancy and can inform therapeutic targets against P. vivax liver-stage infection.
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Affiliation(s)
- Anthony A. Ruberto
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
| | - Steven P. Maher
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
| | - Amélie Vantaux
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Chester J. Joyner
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Caitlin Bourke
- Population Health & Immunity Division, Walter and Eliza Hall Institute, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Balu Balan
- Population Health & Immunity Division, Walter and Eliza Hall Institute, Parkville, VIC, Australia
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Aaron Jex
- Population Health & Immunity Division, Walter and Eliza Hall Institute, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Ivo Mueller
- Population Health & Immunity Division, Walter and Eliza Hall Institute, Parkville, VIC, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC, Australia
| | - Benoit Witkowski
- Malaria Molecular Epidemiology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Dennis E. Kyle
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
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3
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Arias CF, Acosta FJ, Fernandez-Arias C. Killing the competition: a theoretical framework for liver-stage malaria. Open Biol 2022; 12:210341. [PMID: 35350863 PMCID: PMC8965401 DOI: 10.1098/rsob.210341] [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: 01/07/2023] Open
Abstract
The first stage of malaria infections takes place inside the host's hepatocytes. Remarkably, Plasmodium parasites do not infect hepatocytes immediately after reaching the liver. Instead, they migrate through several hepatocytes before infecting their definitive host cells, thus increasing their chances of immune destruction. Considering that malaria can proceed normally without cell traversal, this is indeed a puzzling behaviour. In fact, the role of hepatocyte traversal remains unknown to date, implying that the current understanding of malaria is incomplete. In this work, we hypothesize that the parasites traverse hepatocytes to actively trigger an immune response in the host. This behaviour would be part of a strategy of superinfection exclusion aimed to reduce intraspecific competition during the blood stage of the infection. Based on this hypothesis, we formulate a comprehensive theory of liver-stage malaria that integrates all the available knowledge about the infection. The interest of this new paradigm is not merely theoretical. It highlights major issues in the current empirical approach to the study of Plasmodium and suggests new strategies to fight malaria.
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Affiliation(s)
- Clemente F. Arias
- Centro de Investigaciones Biológicas (CSIC), Madrid, Spain,Grupo Interdisciplinar de Sistemas Complejos de Madrid, Spain
| | | | - Cristina Fernandez-Arias
- Departamento de Inmunología, Universidad Complutense de Madrid, Spain,Instituto de Medicina Molecular, Universidade de Lisboa, Portugal
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4
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He X, Xia L, Tumas KC, Wu J, Su XZ. Type I Interferons and Malaria: A Double-Edge Sword Against a Complex Parasitic Disease. Front Cell Infect Microbiol 2020; 10:594621. [PMID: 33344264 PMCID: PMC7738626 DOI: 10.3389/fcimb.2020.594621] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 10/30/2020] [Indexed: 12/12/2022] Open
Abstract
Type I interferons (IFN-Is) are important cytokines playing critical roles in various infections, autoimmune diseases, and cancer. Studies have also shown that IFN-Is exhibit 'conflicting' roles in malaria parasite infections. Malaria parasites have a complex life cycle with multiple developing stages in two hosts. Both the liver and blood stages of malaria parasites in a vertebrate host stimulate IFN-I responses. IFN-Is have been shown to inhibit liver and blood stage development, to suppress T cell activation and adaptive immune response, and to promote production of proinflammatory cytokines and chemokines in animal models. Different parasite species or strains trigger distinct IFN-I responses. For example, a Plasmodium yoelii strain can stimulate a strong IFN-I response during early infection, whereas its isogenetic strain does not. Host genetic background also greatly influences IFN-I production during malaria infections. Consequently, the effects of IFN-Is on parasitemia and disease symptoms are highly variable depending on the combination of parasite and host species or strains. Toll-like receptor (TLR) 7, TLR9, melanoma differentiation-associated protein 5 (MDA5), and cyclic GMP-AMP synthase (cGAS) coupled with stimulator of interferon genes (STING) are the major receptors for recognizing parasite nucleic acids (RNA/DNA) to trigger IFN-I responses. IFN-I levels in vivo are tightly regulated, and various novel molecules have been identified to regulate IFN-I responses during malaria infections. Here we review the major findings and progress in ligand recognition, signaling pathways, functions, and regulation of IFN-I responses during malaria infections.
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Affiliation(s)
- Xiao He
- Malaria Functional Genomics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, United States
| | - Lu Xia
- Malaria Functional Genomics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, United States
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Keyla C. Tumas
- Malaria Functional Genomics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, United States
| | - Jian Wu
- Malaria Functional Genomics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, United States
| | - Xin-Zhuan Su
- Malaria Functional Genomics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, United States
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5
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γδ-T cells promote IFN-γ-dependent Plasmodium pathogenesis upon liver-stage infection. Proc Natl Acad Sci U S A 2019; 116:9979-9988. [PMID: 31028144 DOI: 10.1073/pnas.1814440116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Cerebral malaria (CM) is a major cause of death due to Plasmodium infection. Both parasite and host factors contribute to the onset of CM, but the precise cellular and molecular mechanisms that contribute to its pathogenesis remain poorly characterized. Unlike conventional αβ-T cells, previous studies on murine γδ-T cells failed to identify a nonredundant role for this T cell subset in experimental cerebral malaria (ECM). Here we show that mice lacking γδ-T cells are resistant to ECM when infected with Plasmodium berghei ANKA sporozoites, the liver-infective form of the parasite and the natural route of infection, in contrast with their susceptible phenotype if challenged with P. berghei ANKA-infected red blood cells that bypass the liver stage of infection. Strikingly, the presence of γδ-T cells enhanced the expression of Plasmodium immunogenic factors and exacerbated subsequent systemic and brain-infiltrating inflammatory αβ-T cell responses. These phenomena were dependent on the proinflammatory cytokine IFN-γ, which was required during liver stage for modulation of the parasite transcriptome, as well as for downstream immune-mediated pathology. Our work reveals an unanticipated critical role of γδ-T cells in the development of ECM upon Plasmodium liver-stage infection.
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TCRβ-expressing macrophages induced by a pathogenic murine malaria correlate with parasite burden and enhanced phagocytic activity. PLoS One 2018; 13:e0201043. [PMID: 30044851 PMCID: PMC6059462 DOI: 10.1371/journal.pone.0201043] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 07/06/2018] [Indexed: 11/19/2022] Open
Abstract
Macrophages express a wide array of invariant receptors that facilitate host defense and mediate pathogenesis during pathogen invasion. We report on a novel population of CD11bhighCD14+F4/80+ macrophages that express TCRβ. This population expands dramatically during a Plasmodium berghei ANKA infection and sequesters in the brain during experimental cerebral malaria. Importantly, measurement of TCRβ transcript and protein levels in macrophages in wildtype versus nude and Rag1 knockout mice establishes that the observed expression is not a consequence of passive receptor expression due to phagocytosis or trogocytosis of peripheral T cells or nonspecific antibody staining to an Fc receptor or cross reactive epitope. We also demonstrate that TCRβ on brain sequestered macrophages undergoes productive gene rearrangements and shows preferential Vβ usage. Remarkably, there is a significant correlation in the proportion of macrophages that express TCRβ and peripheral parasitemia. In addition, presence of TCRβ on the macrophage also correlates with a significant increase (1.9 fold) in the phagocytosis of parasitized erythrocytes. By transcriptional profiling, we identify a novel set of genes and pathways that associate with TCRβ expression by the macrophage. Expansion of TCRβ-expressing macrophages points towards a convergence of the innate and adaptive immune responses where both arms of the immune system cooperate to modulate the host response to malaria and possibly other infections.
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7
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Abstract
Systemic inflammation mediated by Plasmodium parasites is central to malaria disease and its complications. Plasmodium parasites reside in erythrocytes and can theoretically reach all host tissues via the circulation. However, actual interactions between parasitized erythrocytes and host tissues, along with the consequent damage and pathological changes, are limited locally to specific tissue sites. Such tissue specificity of the parasite can alter the outcome of malaria disease, determining whether acute or chronic complications occur. Here, we give an overview of the recent progress that has been made in understanding tissue-specific immunopathology during Plasmodium infection. As knowledge on tissue-specific host-parasite interactions accumulates, better treatment modalities and targets may emerge for intervention in malaria disease.
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8
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Niikura M, Inoue S, Mineo S, Asahi H, Kobayashi F. IFNGR1 signaling is associated with adverse pregnancy outcomes during infection with malaria parasites. PLoS One 2017; 12:e0185392. [PMID: 29117241 PMCID: PMC5678718 DOI: 10.1371/journal.pone.0185392] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 09/12/2017] [Indexed: 11/19/2022] Open
Abstract
Complicated/severe cases of placental pathology due to Plasmodium falciparum and P. vivax, especially adverse pregnancy outcomes during P. vivax infection, have been increasing in recent years. However, the pathogenesis of placental pathology during severe malaria is poorly understood, while responses against IFN-γ are thought to be associated with adverse pregnancy outcomes. In the present study, we explored the role of IFN-γ receptor 1 (IFNGR1) signaling in placental pathology during severe malaria using luciferase-expressing rodent malaria parasites, P. berghei NK65 (PbNK65L). We detected luciferase activities in the lung, spleen, adipose tissue, and placenta in pregnant mice, suggesting that infected erythrocytes could accumulate in various organs during infection. Importantly, we found that fetal mortality in IFNGR1-deficient mice infected with PbNK65L parasites was much less than in infected wild type (WT) mice. Placental pathology was also improved in IFNGR1-deficient mice. In contrast, bioluminescence imaging showed that parasite accumulation in the placentas of IFNGR1-deficient pregnant mice was comparable to that in WT mice infected with PbNK65L. These findings suggest that IFNGR1 signaling plays a pivotal role in placental pathology and subsequent adverse pregnancy outcomes during severe malaria. Our findings may increase our understanding of how disease aggravation occurs during malaria during pregnancy.
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Affiliation(s)
- Mamoru Niikura
- Department of Infectious Diseases, Kyorin University School of Medicine, Tokyo, Japan
| | - Shin–Ichi Inoue
- Department of Infectious Diseases, Kyorin University School of Medicine, Tokyo, Japan
| | - Shoichiro Mineo
- Department of Molecular Pathology, Tokyo Medical University, Tokyo, Japan
| | - Hiroko Asahi
- Department of Infectious Diseases, Kyorin University School of Medicine, Tokyo, Japan
| | - Fumie Kobayashi
- Department of Infectious Diseases, Kyorin University School of Medicine, Tokyo, Japan
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9
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Dietary alterations modulate susceptibility to Plasmodium infection. Nat Microbiol 2017; 2:1600-1607. [PMID: 28947801 DOI: 10.1038/s41564-017-0025-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 08/14/2017] [Indexed: 12/22/2022]
Abstract
The relevance of genetic factors in conferring protection to severe malaria has been demonstrated, as in the case of sickle cell trait and G6PD deficiency 1 . However, it remains unknown whether environmental components, such as dietary or metabolic variations, can contribute to the outcome of infection 2 . Here, we show that administration of a high-fat diet to mice for a period as short as 4 days impairs Plasmodium liver infection by over 90%. Plasmodium sporozoites can successfully invade and initiate replication but die inside hepatocytes, thereby are unable to cause severe disease. Transcriptional analyses combined with genetic and chemical approaches reveal that this impairment of infection is mediated by oxidative stress. We show that reactive oxygen species, probably spawned from fatty acid β-oxidation, directly impact Plasmodium survival inside hepatocytes, and parasite load can be rescued by exogenous administration of the antioxidant N-acetylcysteine or the β-oxidation inhibitor etomoxir. Together, these data reveal that acute and transient dietary alterations markedly impact the establishment of a Plasmodium infection and disease outcome.
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10
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Nair SC, Xu R, Pattaradilokrat S, Wu J, Qi Y, Zilversmit M, Ganesan S, Nagarajan V, Eastman RT, Orandle MS, Tan JC, Myers TG, Liu S, Long CA, Li J, Su XZ. A Plasmodium yoelii HECT-like E3 ubiquitin ligase regulates parasite growth and virulence. Nat Commun 2017; 8:223. [PMID: 28790316 PMCID: PMC5548792 DOI: 10.1038/s41467-017-00267-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 06/12/2017] [Indexed: 01/18/2023] Open
Abstract
Infection of mice with strains of Plasmodium yoelii parasites can result in different pathology, but molecular mechanisms to explain this variation are unclear. Here we show that a P. yoelii gene encoding a HECT-like E3 ubiquitin ligase (Pyheul) influences parasitemia and host mortality. We genetically cross two lethal parasites with distinct disease phenotypes, and identify 43 genetically diverse progeny by typing with microsatellites and 9230 single-nucleotide polymorphisms. A genome-wide quantitative trait loci scan links parasite growth and host mortality to two major loci on chromosomes 1 and 7 with LOD (logarithm of the odds) scores = 6.1 and 8.1, respectively. Allelic exchange of partial sequences of Pyheul in the chromosome 7 locus and modification of the gene expression alter parasite growth and host mortality. This study identifies a gene that may have a function in parasite growth, virulence, and host–parasite interaction, and therefore could be a target for drug or vaccine development. Many strains of Plasmodium differ in virulence, but factors that control these distinctions are not known. Here the authors comparatively map virulence loci using the offspring from a P. yoelii YM and N67 genetic cross, and identify a putative HECT E3 ubiquitin ligase that may explain the variance.
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Affiliation(s)
- Sethu C Nair
- Malaria Functional Genomics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Ruixue Xu
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, 361005, China
| | - Sittiporn Pattaradilokrat
- Malaria Functional Genomics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20892, USA.,Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Jian Wu
- Malaria Functional Genomics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Yanwei Qi
- Malaria Functional Genomics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20892, USA.,State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, 361005, China
| | - Martine Zilversmit
- Malaria Functional Genomics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sundar Ganesan
- Biological Imaging Section, Research Technology Branch, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Vijayaraj Nagarajan
- Bioinformatics and Computational Biosciences Branch, Office of Cyber Infrastructure and Computational Biology, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Richard T Eastman
- Malaria Functional Genomics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Marlene S Orandle
- Comparative Medicine Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - John C Tan
- The Eck Institute of Global Health, Department of Biological Sciences, University of Notre Dame, Indiana, 46556, USA
| | - Timothy G Myers
- Genomic Technologies Section, Research Technologies Branch, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Shengfa Liu
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, 361005, China
| | - Carole A Long
- Malaria Functional Genomics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jian Li
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, 361005, China.
| | - Xin-Zhuan Su
- Malaria Functional Genomics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, MD, 20892, USA. .,State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian, 361005, China.
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11
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Dunst J, Kamena F, Matuschewski K. Cytokines and Chemokines in Cerebral Malaria Pathogenesis. Front Cell Infect Microbiol 2017; 7:324. [PMID: 28775960 PMCID: PMC5517394 DOI: 10.3389/fcimb.2017.00324] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 07/03/2017] [Indexed: 12/18/2022] Open
Abstract
Cerebral malaria is among the major causes of malaria-associated mortality and effective adjunctive therapeutic strategies are currently lacking. Central pathophysiological processes involved in the development of cerebral malaria include an imbalance of pro- and anti-inflammatory responses to Plasmodium infection, endothelial cell activation, and loss of blood-brain barrier integrity. However, the sequence of events, which initiates these pathophysiological processes as well as the contribution of their complex interplay to the development of cerebral malaria remain incompletely understood. Several cytokines and chemokines have repeatedly been associated with cerebral malaria severity. Increased levels of these inflammatory mediators could account for the sequestration of leukocytes in the cerebral microvasculature present during cerebral malaria, thereby contributing to an amplification of local inflammation and promoting cerebral malaria pathogenesis. Herein, we highlight the current knowledge on the contribution of cytokines and chemokines to the pathogenesis of cerebral malaria with particular emphasis on their roles in endothelial activation and leukocyte recruitment, as well as their implication in the progression to blood-brain barrier permeability and neuroinflammation, in both human cerebral malaria and in the murine experimental cerebral malaria model. A better molecular understanding of these processes could provide the basis for evidence-based development of adjunct therapies and the definition of diagnostic markers of disease progression.
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Affiliation(s)
- Josefine Dunst
- Parasitology Unit, Max Planck Institute for Infection BiologyBerlin, Germany.,Institute of Chemistry and Biochemistry, Free UniversityBerlin, Germany.,Molecular Parasitology, Institute of Biology, Humboldt UniversityBerlin, Germany
| | - Faustin Kamena
- Parasitology Unit, Max Planck Institute for Infection BiologyBerlin, Germany.,Institute of Chemistry and Biochemistry, Free UniversityBerlin, Germany.,Molecular Parasitology, Institute of Biology, Humboldt UniversityBerlin, Germany
| | - Kai Matuschewski
- Parasitology Unit, Max Planck Institute for Infection BiologyBerlin, Germany.,Institute of Chemistry and Biochemistry, Free UniversityBerlin, Germany
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12
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Vaughan AM, Kappe SHI. Malaria Parasite Liver Infection and Exoerythrocytic Biology. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a025486. [PMID: 28242785 DOI: 10.1101/cshperspect.a025486] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In their infection cycle, malaria parasites undergo replication and population expansions within the vertebrate host and the mosquito vector. Host infection initiates with sporozoite invasion of hepatocytes, followed by a dramatic parasite amplification event during liver stage parasite growth and replication within hepatocytes. Each liver stage forms up to 90,000 exoerythrocytic merozoites, which are in turn capable of initiating a blood stage infection. Liver stages not only exploit host hepatocyte resources for nutritional needs but also endeavor to prevent hepatocyte cell death and detection by the host's immune system. Research over the past decade has identified numerous parasite factors that play a critical role during liver infection and has started to delineate a complex web of parasite-host interactions that sustain successful parasite colonization of the mammalian host. Targeting the parasites' obligatory infection of the liver as a gateway to the blood, with drugs and vaccines, constitutes the most effective strategy for malaria eradication, as it would prevent clinical disease and onward transmission of the parasite.
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Affiliation(s)
- Ashley M Vaughan
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, Seattle, Washington 98109
| | - Stefan H I Kappe
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, Seattle, Washington 98109.,Department of Global Health, University of Washington, Seattle, Washington 98195
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13
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Yu X, Cai B, Wang M, Tan P, Ding X, Wu J, Li J, Li Q, Liu P, Xing C, Wang HY, Su XZ, Wang RF. Cross-Regulation of Two Type I Interferon Signaling Pathways in Plasmacytoid Dendritic Cells Controls Anti-malaria Immunity and Host Mortality. Immunity 2016; 45:1093-1107. [PMID: 27793594 PMCID: PMC7128466 DOI: 10.1016/j.immuni.2016.10.001] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 08/05/2016] [Accepted: 08/22/2016] [Indexed: 12/29/2022]
Abstract
Type I interferon (IFN) is critical for controlling pathogen infection; however, its regulatory mechanisms in plasmacytoid cells (pDCs) still remain unclear. Here, we have shown that nucleic acid sensors cGAS-, STING-, MDA5-, MAVS-, or transcription factor IRF3-deficient mice produced high amounts of type I IFN-α and IFN-β (IFN-α/β) in the serum and were resistant to lethal plasmodium yoelii YM infection. Robust IFN-α/β production was abolished when gene encoding nucleic acid sensor TLR7, signaling adaptor MyD88, or transcription factor IRF7 was ablated or pDCs were depleted. Further, we identified SOCS1 as a key negative regulator to inhibit MyD88-dependent type I IFN signaling in pDCs. Finally, we have demonstrated that pDCs, cDCs, and macrophages were required for generating IFN-α/β-induced subsequent protective immunity. Thus, our findings have identified a critical regulatory mechanism of type I IFN signaling in pDCs and stage-specific function of immune cells in generating potent immunity against lethal YM infection. cGAS functions as a DNA sensor in vivo for detecting malaria genomic DNA STING- and MAVS-mediated signaling induces a negative regulator SOCS1 expression SOCS1 inhibits MyD88-mediated type I IFN signaling in pDCs Type I IFN produced by pDCs activates cDCs and macrophages for adaptive immunity
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Affiliation(s)
- Xiao Yu
- School of Life Sciences, Sun Yat-Sen University, 510275 Guangzhou, P.R. China; Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Baowei Cai
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA; State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, 361005 Fujian, P.R. China
| | - Mingjun Wang
- Zhongshan School of Medicine, Sun Yat-Sen University, 510275 Guangzhou, P.R. China; Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Peng Tan
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA; Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA
| | - Xilai Ding
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Jian Wu
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jian Li
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, 361005 Fujian, P.R. China
| | - Qingtian Li
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Pinghua Liu
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Changsheng Xing
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Helen Y Wang
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Xin-Zhuan Su
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, 361005 Fujian, P.R. China; Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Rong-Fu Wang
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA; Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, New York, NY 10065, USA; Institute of Biosciences and Technology, College of Medicine, Texas A&M University, Houston, TX 77030, USA.
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14
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Farooq F, Bergmann-Leitner ES. Immune Escape Mechanisms are Plasmodium's Secret Weapons Foiling the Success of Potent and Persistently Efficacious Malaria Vaccines. Clin Immunol 2015; 161:136-43. [PMID: 26342537 DOI: 10.1016/j.clim.2015.08.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 08/27/2015] [Indexed: 10/23/2022]
Abstract
Despite decades of active research, an efficacious vaccine mediating long-term protection is still not available. This review highlights various mechanisms and the different facets by which the parasites outsmart the immune system. An understanding of how the parasites escape immune recognition and interfere with the induction of a protective immune response that provides sterilizing immunity will be crucial to vaccine design.
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Affiliation(s)
- Fouzia Farooq
- Malaria Vaccine Branch, U.S. Military Malaria Research Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910
| | - Elke S Bergmann-Leitner
- Malaria Vaccine Branch, U.S. Military Malaria Research Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910.
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15
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Genome-wide Analysis of Host-Plasmodium yoelii Interactions Reveals Regulators of the Type I Interferon Response. Cell Rep 2015; 12:661-72. [PMID: 26190101 DOI: 10.1016/j.celrep.2015.06.058] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/02/2015] [Accepted: 06/16/2015] [Indexed: 11/22/2022] Open
Abstract
Invading pathogens trigger specific host responses, an understanding of which might identify genes that function in pathogen recognition and elimination. In this study, we performed trans-species expression quantitative trait locus (ts-eQTL) analysis using genotypes of the Plasmodium yoelii malaria parasite and phenotypes of mouse gene expression. We significantly linked 1,054 host genes to parasite genetic loci (LOD score ≥ 3.0). Using LOD score patterns, which produced results that differed from direct expression-level clustering, we grouped host genes that function in related pathways, allowing functional prediction of unknown genes. As a proof of principle, 14 of 15 randomly selected genes predicted to function in type I interferon (IFN-I) responses were experimentally validated using overexpression, small hairpin RNA knockdown, viral infection, and/or infection of knockout mice. This study demonstrates an effective strategy for studying gene function, establishes a functional gene database, and identifies regulators in IFN-I pathways.
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16
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Pérez-Mazliah D, Ng DHL, Freitas do Rosário AP, McLaughlin S, Mastelic-Gavillet B, Sodenkamp J, Kushinga G, Langhorne J. Disruption of IL-21 signaling affects T cell-B cell interactions and abrogates protective humoral immunity to malaria. PLoS Pathog 2015; 11:e1004715. [PMID: 25763578 PMCID: PMC4370355 DOI: 10.1371/journal.ppat.1004715] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 01/29/2015] [Indexed: 12/22/2022] Open
Abstract
Interleukin-21 signaling is important for germinal center B-cell responses, isotype switching and generation of memory B cells. However, a role for IL-21 in antibody-mediated protection against pathogens has not been demonstrated. Here we show that IL-21 is produced by T follicular helper cells and co-expressed with IFN-γ during an erythrocytic-stage malaria infection of Plasmodium chabaudi in mice. Mice deficient either in IL-21 or the IL-21 receptor fail to resolve the chronic phase of P. chabaudi infection and P. yoelii infection resulting in sustained high parasitemias, and are not immune to re-infection. This is associated with abrogated P. chabaudi-specific IgG responses, including memory B cells. Mixed bone marrow chimeric mice, with T cells carrying a targeted disruption of the Il21 gene, or B cells with a targeted disruption of the Il21r gene, demonstrate that IL-21 from T cells signaling through the IL-21 receptor on B cells is necessary to control chronic P. chabaudi infection. Our data uncover a mechanism by which CD4+ T cells and B cells control parasitemia during chronic erythrocytic-stage malaria through a single gene, Il21, and demonstrate the importance of this cytokine in the control of pathogens by humoral immune responses. These data are highly pertinent for designing malaria vaccines requiring long-lasting protective B-cell responses. The importance of antibody and B-cell responses for control of the erythrocytic-stage of the malaria parasite, Plasmodium, was first described when immune serum, passively transferred into Plasmodium falciparum-infected children, reduced parasitemia. This was later confirmed in experimental models in which mice deficient in B cells were unable to eliminate erythrocytic-stage infections. The signals required to activate these protective long-lasting B cell responses towards Plasmodium have not been investigated. IL-21 has been shown to be important for development of B-cell responses after immunization; however, a direct requirement for IL-21 in the control of infection via B-cell dependent mechanisms has never been demonstrated. In this paper, we have used mouse models of erythrocytic P. chabaudi and P. yoelii 17X(NL) infections in combination with IL-21/IL-21R deficiency to show that IL-21 from CD4+ T cells is required to eliminate Plasmodium infection by activating protective, long-lasting B-cell responses. Disruption of IL-21 signaling in B cells prevents the elimination of the parasite resulting in sustained high parasitemias, with no development of memory B-cells, lack of antigen-specific plasma cells and antibodies, and thus no protective immunity against a second challenge infection. Our data demonstrate the absolute requirement of IL-21 for B-cell control of this systemic infection. This has important implications for the design of vaccines against Plasmodium.
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Affiliation(s)
- Damián Pérez-Mazliah
- Division of Parasitology, MRC National Institute for Medical Research (NIMR), London, United Kingdom
| | - Dorothy Hui Lin Ng
- Division of Parasitology, MRC National Institute for Medical Research (NIMR), London, United Kingdom
| | | | - Sarah McLaughlin
- Division of Parasitology, MRC National Institute for Medical Research (NIMR), London, United Kingdom
| | - Béatris Mastelic-Gavillet
- Division of Parasitology, MRC National Institute for Medical Research (NIMR), London, United Kingdom
| | - Jan Sodenkamp
- Division of Parasitology, MRC National Institute for Medical Research (NIMR), London, United Kingdom
| | - Garikai Kushinga
- Division of Parasitology, MRC National Institute for Medical Research (NIMR), London, United Kingdom
| | - Jean Langhorne
- Division of Parasitology, MRC National Institute for Medical Research (NIMR), London, United Kingdom
- * E-mail:
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17
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Innate immunity induced by Plasmodium liver infection inhibits malaria reinfections. Infect Immun 2015; 83:1172-80. [PMID: 25583524 DOI: 10.1128/iai.02796-14] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Following transmission through a mosquito bite to the mammalian host, Plasmodium parasites first invade and replicate inside hepatocytes before infecting erythrocytes and causing malaria. The mechanisms limiting Plasmodium reinfections in humans living in regions of malaria endemicity have mainly been explored by studying the resistance induced by the blood stage of infection. However, epidemiologic studies have suggested that in high-transmission areas, preerythrocytic stages also activate host resistance to reinfection. This, along with the recent discovery that liver infections trigger a specific and effective type I interferon (IFN) response, prompted us to hypothesize that this pre-erythrocyte-stage-induced resistance is linked to liver innate immunity. Here, we combined experimental approaches and mathematical modeling to recapitulate field studies and understand the molecular basis behind such resistance. We present a newly established mouse reinfection model and demonstrate that rodent malaria liver-stage infection inhibits reinfection. This protection relies on the activation of innate immunity and involves the type I IFN response and the antimicrobial cytokine gamma IFN (IFN-γ). Importantly, mathematical simulations indicate that the predictions based on our experimental murine reinfection model fit available epidemiological data. Overall, our study revealed that liver-stage-induced innate immunity may contribute to the preerythrocytic resistance observed in humans in regions of malaria hyperendemicity.
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18
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Plasmodium and mononuclear phagocytes. Microb Pathog 2014; 78:43-51. [PMID: 25450889 DOI: 10.1016/j.micpath.2014.11.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 11/14/2014] [Accepted: 11/19/2014] [Indexed: 01/13/2023]
Abstract
Plasmodium, the causative agent of malaria, initially multiplies inside liver cells and then in successive cycles inside erythrocytes, causing the symptoms of the disease. In this review, we discuss interactions between the extracellular and intracellular forms of the Plasmodium parasite and innate immune cells in the mammalian host, with a special emphasis on mononuclear phagocytes. We overview here what is known about the innate immune cells that interact with parasites, mechanisms used by the parasite to evade them, and the protective or detrimental contribution of these interactions on parasite progression through its life cycle and pathology in the host.
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19
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Storm J, Craig AG. Pathogenesis of cerebral malaria--inflammation and cytoadherence. Front Cell Infect Microbiol 2014; 4:100. [PMID: 25120958 PMCID: PMC4114466 DOI: 10.3389/fcimb.2014.00100] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 07/07/2014] [Indexed: 01/08/2023] Open
Abstract
Despite decades of research on cerebral malaria (CM) there is still a paucity of knowledge about what actual causes CM and why certain people develop it. Although sequestration of P. falciparum infected red blood cells has been linked to pathology, it is still not clear if this is directly or solely responsible for this clinical syndrome. Recent data have suggested that a combination of parasite variant types, mainly defined by the variant surface antigen, P. falciparum erythrocyte membrane protein 1 (PfEMP1), its receptors, coagulation and host endothelial cell activation (or inflammation) are equally important. This makes CM a multi-factorial disease and a challenge to unravel its causes to decrease its detrimental impact.
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Affiliation(s)
- Janet Storm
- Department of Parasitology, Liverpool School of Tropical Medicine Liverpool, UK ; Malawi Liverpool Wellcome Trust Clinical Research Programme (MLW), University of Malawi College of Medicine Blantyre, Malawi
| | - Alister G Craig
- Department of Parasitology, Liverpool School of Tropical Medicine Liverpool, UK
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20
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Zuzarte-Luis V, Mota MM, Vigário AM. Malaria infections: what and how can mice teach us. J Immunol Methods 2014; 410:113-22. [PMID: 24837740 DOI: 10.1016/j.jim.2014.05.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/24/2014] [Accepted: 05/01/2014] [Indexed: 01/07/2023]
Abstract
Malaria imposes a horrific public health burden - hundreds of millions of infections and millions of deaths - on large parts of the world. While this unacceptable health burden and its economic and social impact have made it a focal point of the international development agenda, it became consensual that malaria control or elimination will be difficult to attain prior to gain a better understanding of the complex interactions occurring between its main players: Plasmodium, the causative agent of disease, and its hosts. Practical and ethical limitations exist regarding the ability to carry out research with human subjects or with human samples. In this review, we highlight how rodent models of infection have contributed significantly during the past decades to a better understanding of the basic biology of the parasite, host response and pathogenesis.
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Affiliation(s)
- Vanessa Zuzarte-Luis
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Maria M Mota
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal.
| | - Ana M Vigário
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, 1649-028 Lisboa, Portugal; Unidade de Ciências Médicas, Centro de Competência de Ciências da Vida, Universidade da Madeira, Funchal, Portugal.
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21
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Miller J, Sack B, Baldwin M, Vaughan A, Kappe S. Interferon-Mediated Innate Immune Responses against Malaria Parasite Liver Stages. Cell Rep 2014; 7:436-447. [DOI: 10.1016/j.celrep.2014.03.018] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 02/07/2014] [Accepted: 03/11/2014] [Indexed: 01/25/2023] Open
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22
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Rodrigues V, Cordeiro-da-Silva A, Laforge M, Ouaissi A, Akharid K, Silvestre R, Estaquier J. Impairment of T cell function in parasitic infections. PLoS Negl Trop Dis 2014; 8:e2567. [PMID: 24551250 PMCID: PMC3923671 DOI: 10.1371/journal.pntd.0002567] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In mammals subverted as hosts by protozoan parasites, the latter and/or the agonists they release are detected and processed by sensors displayed by many distinct immune cell lineages, in a tissue(s)-dependent context. Focusing on the T lymphocyte lineage, we review our present understanding on its transient or durable functional impairment over the course of the developmental program of the intracellular parasites Leishmania spp., Plasmodium spp., Toxoplasma gondii, and Trypanosoma cruzi in their mammalian hosts. Strategies employed by protozoa to down-regulate T lymphocyte function may act at the initial moment of naïve T cell priming, rendering T cells anergic or unresponsive throughout infection, or later, exhausting T cells due to antigen persistence. Furthermore, by exploiting host feedback mechanisms aimed at maintaining immune homeostasis, parasites can enhance T cell apoptosis. We will discuss how infections with prominent intracellular protozoan parasites lead to a general down-regulation of T cell function through T cell anergy and exhaustion, accompanied by apoptosis, and ultimately allowing pathogen persistence.
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Affiliation(s)
- Vasco Rodrigues
- CNRS FRE 3235, Université Paris Descartes, Paris, France
- Parasite Disease Group, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Anabela Cordeiro-da-Silva
- Parasite Disease Group, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Departamento de Ciências Biológicas, Faculdade de Farmácia da Universidade do Porto, Porto, Portugal
| | | | - Ali Ouaissi
- Parasite Disease Group, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Khadija Akharid
- Département de Biologie, Faculté des Sciences Aîn-Chock, Université Hassan II-Casablanca, Casablanca, Maroc
| | - Ricardo Silvestre
- Parasite Disease Group, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- * E-mail: (RS); (JE)
| | - Jérôme Estaquier
- CNRS FRE 3235, Université Paris Descartes, Paris, France
- Université Laval, Centre de Recherche en Infectiologie, Québec, Canada
- * E-mail: (RS); (JE)
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23
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Abstract
Organisms have evolved numerous strategies to control infection by an array of intracellular pathogens. One cell autonomous pathogen control strategy is global inhibition of protein synthesis via stress granule (SG) formation. SGs are induced by stressful stimuli such as oxidative stress and nutrient deprivation, and are known to counteract both viral and bacterial infections. Pathogens, in turn, may actively block an infected cell's ability to form SGs. In vitro and in vivo, many liver stage malaria parasites are eliminated during development. We show here that SG formation is not amongst the strategies used for elimination of parasites from hepatocytes. Neither cell traversal, sporozoite invasion, nor rapid parasite growth leads to the formation of SGs. Furthermore, Plasmodium berghei infection does not compromise the ability of infected cells to assemble SGs in response to oxidative or nutritional stress. Plasmodium infection is therefore not detected by hepatocytes as a strong stressor necessitating global translational repression in response, highlighting the idea that Plasmodium has evolved strategies to ensure its remarkable growth in the hepatocyte while maintaining host cell homeostasis.
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Affiliation(s)
- Kirsten K Hanson
- Instituto de Medicina Molecular, Avenida Professor Egas Moniz, Lisbon 1649-028, Portugal
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24
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Strain-specific innate immune signaling pathways determine malaria parasitemia dynamics and host mortality. Proc Natl Acad Sci U S A 2014; 111:E511-20. [PMID: 24474800 DOI: 10.1073/pnas.1316467111] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Malaria infection triggers vigorous host immune responses; however, the parasite ligands, host receptors, and the signaling pathways responsible for these reactions remain unknown or controversial. Malaria parasites primarily reside within RBCs, thereby hiding themselves from direct contact and recognition by host immune cells. Host responses to malaria infection are very different from those elicited by bacterial and viral infections and the host receptors recognizing parasite ligands have been elusive. Here we investigated mouse genome-wide transcriptional responses to infections with two strains of Plasmodium yoelii (N67 and N67C) and discovered differences in innate response pathways corresponding to strain-specific disease phenotypes. Using in vitro RNAi-based gene knockdown and KO mice, we demonstrated that a strong type I IFN (IFN-I) response triggered by RNA polymerase III and melanoma differentiation-associated protein 5, not Toll-like receptors (TLRs), binding of parasite DNA/RNA contributed to a decline of parasitemia in N67-infected mice. We showed that conventional dendritic cells were the major sources of early IFN-I, and that surface expression of phosphatidylserine on infected RBCs might promote their phagocytic uptake, leading to the release of parasite ligands and the IFN-I response in N67 infection. In contrast, an elevated inflammatory response mediated by CD14/TLR and p38 signaling played a role in disease severity and early host death in N67C-infected mice. In addition to identifying cytosolic DNA/RNA sensors and signaling pathways previously unrecognized in malaria infection, our study demonstrates the importance of parasite genetic backgrounds in malaria pathology and provides important information for studying human malaria pathogenesis.
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25
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Liehl P, Zuzarte-Luís V, Chan J, Zillinger T, Baptista F, Carapau D, Konert M, Hanson KK, Carret C, Lassnig C, Müller M, Kalinke U, Saeed M, Chora AF, Golenbock DT, Strobl B, Prudêncio M, Coelho LP, Kappe SH, Superti-Furga G, Pichlmair A, Vigário AM, Rice CM, Fitzgerald KA, Barchet W, Mota MM. Host-cell sensors for Plasmodium activate innate immunity against liver-stage infection. Nat Med 2013; 20:47-53. [PMID: 24362933 DOI: 10.1038/nm.3424] [Citation(s) in RCA: 205] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 11/08/2013] [Indexed: 12/15/2022]
Abstract
Before they infect red blood cells and cause malaria, Plasmodium parasites undergo an obligate and clinically silent expansion phase in the liver that is supposedly undetected by the host. Here, we demonstrate the engagement of a type I interferon (IFN) response during Plasmodium replication in the liver. We identified Plasmodium RNA as a previously unrecognized pathogen-associated molecular pattern (PAMP) capable of activating a type I IFN response via the cytosolic pattern recognition receptor Mda5. This response, initiated by liver-resident cells through the adaptor molecule for cytosolic RNA sensors, Mavs, and the transcription factors Irf3 and Irf7, is propagated by hepatocytes in an interferon-α/β receptor-dependent manner. This signaling pathway is critical for immune cell-mediated host resistance to liver-stage Plasmodium infection, which we find can be primed with other PAMPs, including hepatitis C virus RNA. Together, our results show that the liver has sensor mechanisms for Plasmodium that mediate a functional antiparasite response driven by type I IFN.
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Affiliation(s)
- Peter Liehl
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Vanessa Zuzarte-Luís
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Jennie Chan
- 1] Department of Medicine, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, USA. [2]
| | - Thomas Zillinger
- 1] Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital of Bonn, Bonn, Germany. [2]
| | - Fernanda Baptista
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Daniel Carapau
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Madlen Konert
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Kirsten K Hanson
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Céline Carret
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Caroline Lassnig
- Institute of Animal Breeding and Genetics and Biomodels, Austria University of Veterinary Medicine Vienna, Vienna, Austria
| | - Mathias Müller
- Institute of Animal Breeding and Genetics and Biomodels, Austria University of Veterinary Medicine Vienna, Vienna, Austria
| | - Ulrich Kalinke
- Institute for Experimental Infection Research, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover Medical School and Helmholtz Centre for Infection Research, Hannover, Germany
| | - Mohsan Saeed
- Laboratory of Virology and Infectious Diseases, Center for the Study of Hepatitis C, The Rockefeller University, New York, New York, USA
| | - Angelo Ferreira Chora
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Douglas T Golenbock
- Department of Medicine, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Birgit Strobl
- Institute of Animal Breeding and Genetics and Biomodels, Austria University of Veterinary Medicine Vienna, Vienna, Austria
| | - Miguel Prudêncio
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Luis P Coelho
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
| | - Stefan H Kappe
- Seattle Biomedical Research Institute, Seattle, Washington, USA
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Andreas Pichlmair
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Ana M Vigário
- 1] Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal. [2] Unidade de Ciências Médicas, Centro de compentência de ciências da vida, Universidade da Madeira, Funchal, Portugal
| | - Charles M Rice
- Laboratory of Virology and Infectious Diseases, Center for the Study of Hepatitis C, The Rockefeller University, New York, New York, USA
| | - Katherine A Fitzgerald
- Department of Medicine, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Winfried Barchet
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital of Bonn, Bonn, Germany
| | - Maria M Mota
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, Lisboa, Portugal
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26
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TREM2 governs Kupffer cell activation and explains belr1 genetic resistance to malaria liver stage infection. Proc Natl Acad Sci U S A 2013; 110:19531-6. [PMID: 24218563 DOI: 10.1073/pnas.1306873110] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Plasmodium liver stage infection is a target of interest for the treatment of and vaccination against malaria. Here we used forward genetics to search for mechanisms underlying natural host resistance to infection and identified triggering receptor expressed on myeloid cells 2 (TREM2) and MHC class II molecules as determinants of Plasmodium berghei liver stage infection in mice. Locus belr1 confers resistance to malaria liver stage infection. The use of newly derived subcongenic mouse lines allowed to map belr1 to a 4-Mb interval on mouse chromosome 17 that contains the Trem2 gene. We show that Trem2 expression in the nonparenchymal liver cells closely correlates with resistance to liver stage infection, implicating TREM2 as a mediator of the belr1 genetic effect. Trem2-deficient mice are more susceptible to liver stage infection than their WT counterparts. We found that Kupffer cells are the principle cells expressing TREM2 in the liver, and that Trem2(-/-) Kupffer cells display altered functional activation on exposure to P. berghei sporozoites. TREM2 expression in Kupffer cells contributes to the limitation of parasite expansion in isolated hepatocytes in vitro, potentially explaining the increased susceptibility of Trem2(-/-) mice to liver stage infection. The MHC locus was also found to control liver parasite burden, possibly owing to the expression of MHC class II molecules in hepatocytes. Our findings implicate unexpected Kupffer-hepatocyte cross-talk in the control Plasmodium liver stage infection and demonstrate that TREM2 is involved in host responses against the malaria parasite.
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27
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Sortica VA, Cunha MG, Ohnishi MDO, Souza JM, Ribeiro-dos-Santos ÂKC, Santos SEB, Hutz MH. Role of IL6, IL12B and VDR gene polymorphisms in Plasmodium vivax malaria severity, parasitemia and gametocytemia levels in an Amazonian Brazilian population. Cytokine 2013; 65:42-7. [PMID: 24139871 DOI: 10.1016/j.cyto.2013.09.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 09/09/2013] [Accepted: 09/19/2013] [Indexed: 12/29/2022]
Abstract
OBJECTIVE To investigate the influence of IL6, IL12B and VDR single nucleotide polymorphisms (SNPs) in uncomplicated Plasmodium vivax infection symptoms intensity, parasitemia and gametocytemia levels in a Brazilian Amazonian population. METHODS A total of 167 malaria patients infected by P. vivax have parasitemia and gametocytemia levels estimated before treatment. Fourteen clinical symptoms were evaluated and included in a principal component analysis to derive a clinical symptom index. Patients were genotyped for IL6-174C>G, IL12B 735T>C, 458A>G, 159A>C, and VDR FokI, TaqI, BsmI SNPs by Taqman 5' nuclease assays. A General Linear Model analysis of covariance with age, gender, exposure period and infection history and genetic ancestry was performed to investigate the association of genotypes with parasitemia and gametocytemia levels and with a clinical symptom index. RESULTS Higher parasitemia levels were observed in IL6-174C carriers (p=0.02) whereas IL12B CGT haplotype carriers presented lower parasitemia levels (p=0.008). VDR TaqIC/BsmIA haplotype carriers showed higher gametocyte levels than non-carriers (p=0.013). Based on the clinical index values the IL6-174C>G polymorphism was associated with malaria severity. The IL6-174C carriers presented a more severe clinical index when compared to GG homozygotes (p=0.001). CONCLUSION The present study suggests that IL6, IL12 and VDR influence severity, parasitemia and gametocytemia clearance in P. vivax infections, and highlights their potential role in malaria immune response in an Amazonian population.
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Affiliation(s)
- Vinicius A Sortica
- Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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28
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Riley EM, Stewart VA. Immune mechanisms in malaria: new insights in vaccine development. Nat Med 2013; 19:168-78. [DOI: 10.1038/nm.3083] [Citation(s) in RCA: 144] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 01/07/2013] [Indexed: 02/07/2023]
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Monocytes and macrophages in malaria: protection or pathology? Trends Parasitol 2012; 29:26-34. [PMID: 23142189 DOI: 10.1016/j.pt.2012.10.002] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/12/2012] [Accepted: 10/16/2012] [Indexed: 02/07/2023]
Abstract
Recruitment and activation of monocytes and macrophages are essential for clearance of malaria infection, but these have also been associated with adverse clinical outcomes. In this review we discuss recent discoveries on how distinct molecular interactions between monocytes, macrophages, and malaria parasites may alter the balance between protection and pathology in malaria-infected individuals. The immunopathology of severe malaria often originates from excessive immune activation by parasites. The involvement of monocytes and macrophages in these events is highlighted, and priorities for future research to clarify the roles of these cells in malaria are proposed. Knowledge of the factors influencing the balance between protection and pathology can assist in the design of therapeutics aimed at modulating monocyte and macrophage functions to improve outcomes.
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Baum J, Saliba KJ, Cooke BM. Editorial--Molecular Approaches to Malaria 2012 (MAM 2012). Int J Parasitol 2012; 42:517. [PMID: 22656266 DOI: 10.1016/j.ijpara.2012.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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