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Rankawat S, Kundal K, Chakraborty S, Kumar R, Ray S. A comprehensive rhythmicity analysis of host proteins and immune factors involved in malaria pathogenesis to decipher the importance of host circadian clock in malaria. Front Immunol 2023; 14:1210299. [PMID: 37638001 PMCID: PMC10449258 DOI: 10.3389/fimmu.2023.1210299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 07/17/2023] [Indexed: 08/29/2023] Open
Abstract
Background Circadian rhythms broadly impact human health by regulating our daily physiological and metabolic processes. The circadian clocks substantially regulate our immune responses and susceptibility to infections. Malaria parasites have intrinsic molecular oscillations and coordinate their infection cycle with host rhythms. Considering the cyclical nature of malaria, a clear understanding of the circadian regulations in malaria pathogenesis and host responses is of immense importance. Methods We have thoroughly investigated the transcript level rhythmic patterns in blood proteins altered in falciparum and vivax malaria and malaria-related immune factors in mice, baboons, and humans by analyzing datasets from published literature and comprehensive databases. Using the Metascape and DAVID platforms, we analyzed Gene Ontology terms and physiological pathways associated with the rhythmic malaria-associated host immune factors. Results We observed that almost 50% of the malaria-associated host immune factors are rhythmic in mice and humans. Overlapping rhythmic genes identified in mice, baboons, and humans, exhibited enrichment (Q < 0.05, fold-enrichment > 5) of multiple physiological pathways essential for host immune and defense response, including cytokine production, leukocyte activation, cellular defense, and response, regulation of kinase activity, B-cell receptor signaling pathway, and cellular response to cytokine stimulus. Conclusions Our analysis indicates a robust circadian regulation on multiple interconnected host response pathways and immunological networks in malaria, evident from numerous rhythmic genes involved in those pathways. Host immune rhythms play a vital role in the temporal regulation of host-parasite interactions and defense machinery in malaria.
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Affiliation(s)
| | | | | | | | - Sandipan Ray
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi, Telangana, India
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In Vivo Imaging of the Buccal Mucosa Shows Loss of the Endothelial Glycocalyx and Perivascular Hemorrhages in Pediatric Plasmodium falciparum Malaria. Infect Immun 2020; 88:IAI.00679-19. [PMID: 31871101 DOI: 10.1128/iai.00679-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/16/2019] [Indexed: 12/11/2022] Open
Abstract
Severe malaria is mostly caused by Plasmodium falciparum, resulting in considerable, systemic inflammation and pronounced endothelial activation. The endothelium forms an interface between blood and tissue, and vasculopathy has previously been linked with malaria severity. We studied the extent to which the endothelial glycocalyx that normally maintains endothelial function is involved in falciparum malaria pathogenesis by using incident dark-field imaging in the buccal mucosa. This enabled calculation of the perfused boundary region, which indicates to what extent erythrocytes can permeate the endothelial glycocalyx. The perfused boundary region was significantly increased in severe malaria patients and mirrored by an increase of soluble glycocalyx components in plasma. This is suggestive of a substantial endothelial glycocalyx loss. Patients with severe malaria had significantly higher plasma levels of sulfated glycosaminoglycans than patients with uncomplicated malaria, whereas other measured glycocalyx markers were raised to a comparable extent in both groups. In severe malaria, the plasma level of the glycosaminoglycan hyaluronic acid was positively correlated with the perfused boundary region in the buccal cavity. Plasma hyaluronic acid and heparan sulfate were particularly high in severe malaria patients with a low Blantyre coma score, suggesting involvement in its pathogenesis. In vivo imaging also detected perivascular hemorrhages and sequestering late-stage parasites. In line with this, plasma angiopoietin-1 was decreased while angiopoietin-2 was increased, suggesting vascular instability. The density of hemorrhages correlated negatively with plasma levels of angiopoietin-1. Our findings indicate that as with experimental malaria, the loss of endothelial glycocalyx is associated with vascular dysfunction in human malaria and is related to severity.
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Jantzie L, El Demerdash N, Newville JC, Robinson S. Time to reconsider extended erythropoietin treatment for infantile traumatic brain injury? Exp Neurol 2019; 318:205-215. [PMID: 31082389 DOI: 10.1016/j.expneurol.2019.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 05/03/2019] [Accepted: 05/08/2019] [Indexed: 01/03/2023]
Abstract
Pediatric traumatic brain injury (TBI) remains a leading cause of childhood morbidity and mortality worldwide. Most efforts to reduce the chronic impact of pediatric TBI involve prevention and minimization of secondary injury. Currently, no treatments are used in routine clinical care during the acute and subacute phases to actively repair injury to the developing brain. The endogenous pluripotent cytokine erythropoietin (EPO) holds promise as an emerging neuroreparative agent in perinatal brain injury (PBI). EPO signaling in the central nervous system (CNS) is essential for multiple stages of neurodevelopment, including the genesis, survival and differentiation of multiple lineages of neural cells. Postnatally, EPO signaling decreases markedly as the CNS matures. Importantly, high-dose, extended EPO regimens have shown efficacy in preclinical controlled cortical impact (CCI) models of infant TBI at two different, early ages by independent research groups. Specifically, extended high-dose EPO treatment after infantile CCI prevents long-term cognitive deficits in adult rats. Because of the striking differences in the molecular and cellular responses to both injury and recovery in the developing and mature CNS, and the excellent safety profile of EPO in infants and children, extended courses of EPO are currently in Phase III trials for neonates with PBI. Extended, high-dose EPO may also warrant testing for infants and young children with TBI.
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Affiliation(s)
- Lauren Jantzie
- Division of Neonatology, Department of Pediatrics, University of New Mexico School of Medicine, Albuquerque, NM, 87111,United States.; Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, 87111, United States..
| | - Nagat El Demerdash
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21287, United States
| | - Jessie C Newville
- Division of Neonatology, Department of Pediatrics, University of New Mexico School of Medicine, Albuquerque, NM, 87111,United States.; Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, 87111, United States
| | - Shenandoah Robinson
- Division of Pediatric Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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Hempel C, Sporring J, Kurtzhals JAL. Experimental cerebral malaria is associated with profound loss of both glycan and protein components of the endothelial glycocalyx. FASEB J 2018; 33:2058-2071. [DOI: 10.1096/fj.201800657r] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Casper Hempel
- Centre for Medical ParasitologyDepartment of Clinical MicrobiologyCopenhagen University HospitalCopenhagenDenmark
- Department of Immunology and MicrobiologyUniversity of CopenhagenCopenhagenDenmark
- Department of Micro- and NanotechnologyTechnical University of DenmarkLyngbyDenmark
| | - Jon Sporring
- Department for Computer SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Jørgen Anders Lindholm Kurtzhals
- Centre for Medical ParasitologyDepartment of Clinical MicrobiologyCopenhagen University HospitalCopenhagenDenmark
- Department of Immunology and MicrobiologyUniversity of CopenhagenCopenhagenDenmark
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Hempel C, Wang CW, Kurtzhals JAL, Staalsø T. Binding of Plasmodium falciparum to CD36 can be shielded by the glycocalyx. Malar J 2017; 16:193. [PMID: 28486940 PMCID: PMC5424350 DOI: 10.1186/s12936-017-1844-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 04/27/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Plasmodium falciparum-infected erythrocytes sequester in the microcirculation due to interaction between surface-expressed parasite proteins and endothelial receptors. Endothelial cells are covered in a carbohydrate-rich glycocalyx that shields against undesired leukocyte adhesion. It was investigated if the cellular glycocalyx affects the binding of P. falciparum-infected erythrocytes to CD36 in vitro. METHODS Glycocalyx growth was followed in vitro by using azido sugars and cationized ferritin detecting O-glycoproteins and negatively charged proteoglycans, respectively. P. falciparum (clone FCR3/IT) was selected on Chinese hamster ovary (CHO) cells transfected with human CD36. Cytoadhesion to CHO CD36 at 1-4 days after seeding was quantified by using a static binding assay. RESULTS The glycocalyx thickness of CHO cells increased during 4 days in culture as assessed by metabolic labelling of glycans with azido sugars and with electron microscopy studying the binding of cationized ferritin to cell surfaces. The functional importance of this process was addressed in binding assays by using CHO cells transfected with CD36. In parallel with the maturation of the glycocalyx, antibody-binding to CD36 was inhibited, despite stable expression of CD36. P. falciparum selected for CD36-binding recognized CD36 on CHO cells on the first day in culture, but the binding was lost after 2-4 days. CONCLUSION The endothelial glycocalyx affects parasite cytoadhesion in vitro, an effect that has previously been ignored. The previously reported loss of glycocalyx during experimental malaria may play an important role in the pathogenesis of malaria complications by allowing the close interaction between infected erythrocytes and endothelial receptors.
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Affiliation(s)
- Casper Hempel
- Department of Clinical Microbiology, Centre for Medical Parasitology, Copenhagen University Hospital, Copenhagen, Denmark. .,Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. .,Department of Micro- and Nanotechnology, Technical University of Denmark, Kongens Lyngby, Denmark.
| | - Christian William Wang
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Jørgen Anders Lindholm Kurtzhals
- Department of Clinical Microbiology, Centre for Medical Parasitology, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Trine Staalsø
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Rex TS, Kasmala L, Bond WS, de Lucas Cerrillo AM, Wynn K, Lewin AS. Erythropoietin Slows Photoreceptor Cell Death in a Mouse Model of Autosomal Dominant Retinitis Pigmentosa. PLoS One 2016; 11:e0157411. [PMID: 27299810 PMCID: PMC4907422 DOI: 10.1371/journal.pone.0157411] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 05/27/2016] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To test the efficacy of systemic gene delivery of a mutant form of erythropoietin (EPO-R76E) that has attenuated erythropoietic activity, in a mouse model of autosomal dominant retinitis pigmentosa. METHODS Ten-day old mice carrying one copy of human rhodopsin with the P23H mutation and both copies of wild-type mouse rhodopsin (hP23H RHO+/-,mRHO+/+) were injected into the quadriceps with recombinant adeno-associated virus (rAAV) carrying either enhanced green fluorescent protein (eGFP) or EpoR76E. Visual function (electroretinogram) and retina structure (optical coherence tomography, histology, and immunohistochemistry) were assessed at 7 and 12 months of age. RESULTS The outer nuclear layer thickness decreased over time at a slower rate in rAAV.EpoR76E treated as compared to the rAAV.eGFP injected mice. There was a statistically significant preservation of the electroretinogram at 7, but not 12 months of age. CONCLUSIONS Systemic EPO-R76E slows death of the photoreceptors and vision loss in hP23H RHO+/-,mRHO+/+ mice. Treatment with EPO-R76E may widen the therapeutic window for retinal degeneration patients by increasing the number of viable cells. Future studies might investigate if co-treatment with EPO-R76E and gene replacement therapy is more effective than gene replacement therapy alone.
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Affiliation(s)
- Tonia S. Rex
- Vanderbilt Eye Institute, Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, United States of America
| | - Lorraine Kasmala
- Vanderbilt Eye Institute, Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, United States of America
| | - Wesley S. Bond
- Vanderbilt Eye Institute, Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, United States of America
| | - Ana M. de Lucas Cerrillo
- Vanderbilt Eye Institute, Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, United States of America
| | - Kristi Wynn
- Vanderbilt Eye Institute, Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, United States of America
| | - Alfred S. Lewin
- Department of Molecular Genetics & Microbiology, University of Florida, Gainesville, FL 32608, United States of America
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Carvalho TG, Morahan B, John von Freyend S, Boeuf P, Grau G, Garcia-Bustos J, Doerig C. The ins and outs of phosphosignalling in Plasmodium: Parasite regulation and host cell manipulation. Mol Biochem Parasitol 2016; 208:2-15. [PMID: 27211241 DOI: 10.1016/j.molbiopara.2016.05.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 05/16/2016] [Indexed: 12/15/2022]
Abstract
Signal transduction and kinomics have been rapidly expanding areas of investigation within the malaria research field. Here, we provide an overview of phosphosignalling pathways that operate in all stages of the Plasmodium life cycle. We review signalling pathways in the parasite itself, in the cells it invades, and in other cells of the vertebrate host with which it interacts. We also discuss the potential of these pathways as novel targets for antimalarial intervention.
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Affiliation(s)
- Teresa Gil Carvalho
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Belinda Morahan
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Simona John von Freyend
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Philippe Boeuf
- Burnet Institute, Melbourne, Victoria 3004, Australia; The University of Melbourne, Department of Medicine, Melbourne, Victoria 3010, Australia; Victorian Infectious Diseases Service, Royal Melbourne Hospital, Melbourne, Victoria 3010, Australia
| | - Georges Grau
- Vascular Immunology Unit, Department of Pathology, Sydney Medical School, University of Sydney, Camperdown, New South Wales 2050, Australia
| | - Jose Garcia-Bustos
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria 3800, Australia
| | - Christian Doerig
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Victoria 3800, Australia.
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Langhorne J, Duffy PE. Expanding the antimalarial toolkit: Targeting host-parasite interactions. J Exp Med 2016; 213:143-53. [PMID: 26834158 PMCID: PMC4749928 DOI: 10.1084/jem.20151677] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 12/21/2015] [Indexed: 12/27/2022] Open
Abstract
Recent successes in malaria control are threatened by drug-resistant Plasmodium parasites and insecticide-resistant Anopheles mosquitoes, and first generation vaccines offer only partial protection. New research approaches have highlighted host as well as parasite molecules or pathways that could be targeted for interventions. In this study, we discuss host–parasite interactions at the different stages of the Plasmodium life cycle within the mammalian host and the potential for therapeutics that prevent parasite migration, invasion, intracellular growth, or egress from host cells, as well as parasite-induced pathology.
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Affiliation(s)
- Jean Langhorne
- Mill Hill Laboratory, The Francis Crick Institute, London NW7 1AA, England, UK
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852
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CAHAYANI WA, NORAHMAWATI E, BUDIARTI N, FITRI LE. Increased CD11b and Hypoxia-Inducible Factors-1alpha Expressions in the Lung Tissue and Surfactant Protein-D Levels in Serum Are Related with Acute Lung Injury in Severe Malaria of C57BL/6 Mice. IRANIAN JOURNAL OF PARASITOLOGY 2016; 11:303-315. [PMID: 28127335 PMCID: PMC5256046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND We aimed to reveal the role of CD11b and hypoxia-inducible factors-1alpha (HIF-1α) expressions on monocytes and alveolar macrophages of lung tissue, and the levels of serum surfactant protein-D (SP-D) in severe malaria-associated acute lung injury (ALI). METHODS The C57BL/6 mice were divided into control group, renal malaria group (inoculated with 106Plasmodium berghei ANKA), and cerebral malaria group (inoculated with 107P. berghei ANKA). The expressions of CD11b and HIF-1α in lung tissue were observed by immunohistochemistry, and serum SP-D levels were measured by ELISA. This study was conducted from June 2014 to February 2015 in the Laboratory of Parasitology, Faculty of Medicine, Universitas Brawijaya, Malang. RESULTS The CD11b expression on pulmonary tissue of renal and cerebral malaria mice were significantly higher than control mice (P=0.002; P=0.002), as well as the HIF-1α expression on pulmonary tissue (P=0.002; P=0.002). The level of serum SP-D in renal malaria and cerebral malaria mice were significantly higher than control mice (P=0.002; P=0.002). We found a strong correlation between the expression of CD11b and HIF-1α in lung tissue (r=0.937, P=0.000), as well as between CD11b expression and serum SP-D levels (r=0.907, P=0.000) and between HIF-1α expression and serum SP-D levels (r=0.913, P=0.000). CONCLUSION Severe malaria-associated ALI increased the expression of CD11b and HIF-1α in the lung tissue and increased serum SP-D levels of C57BL/6 mice significantly.
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Affiliation(s)
- Wike Astrid CAHAYANI
- Master Program in Biomedical Sciences, Faculty of Medicine, Universitas Brawijaya, Malang, Indonesia
| | - Eviana NORAHMAWATI
- Dept. of Anatomic Pathology, Dr. Saiful Anwar Hospital/Faculty of Medicine, Universitas Brawijaya, Malang, Indonesia
| | - Niniek BUDIARTI
- Division of Tropical Infection, Dept. of Internal Medicine, Dr. Saiful Anwar Hospital/Faculty of Medicine, Universitas Brawijaya, Malang, Indonesia
| | - Loeki Enggar FITRI
- Dept. of Parasitology, Faculty of Medicine, Universitas Brawijaya, Malang, Indonesia,Correspondence
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Deroost K, Pham TT, Opdenakker G, Van den Steen PE. The immunological balance between host and parasite in malaria. FEMS Microbiol Rev 2015; 40:208-57. [PMID: 26657789 DOI: 10.1093/femsre/fuv046] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2015] [Indexed: 12/16/2022] Open
Abstract
Coevolution of humans and malaria parasites has generated an intricate balance between the immune system of the host and virulence factors of the parasite, equilibrating maximal parasite transmission with limited host damage. Focusing on the blood stage of the disease, we discuss how the balance between anti-parasite immunity versus immunomodulatory and evasion mechanisms of the parasite may result in parasite clearance or chronic infection without major symptoms, whereas imbalances characterized by excessive parasite growth, exaggerated immune reactions or a combination of both cause severe pathology and death, which is detrimental for both parasite and host. A thorough understanding of the immunological balance of malaria and its relation to other physiological balances in the body is of crucial importance for developing effective interventions to reduce malaria-related morbidity and to diminish fatal outcomes due to severe complications. Therefore, we discuss in this review the detailed mechanisms of anti-malarial immunity, parasite virulence factors including immune evasion mechanisms and pathogenesis. Furthermore, we propose a comprehensive classification of malaria complications according to the different types of imbalances.
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Affiliation(s)
- Katrien Deroost
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium The Francis Crick Institute, Mill Hill Laboratory, London, NW71AA, UK
| | - Thao-Thy Pham
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Ghislain Opdenakker
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Philippe E Van den Steen
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
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Perivascular Arrest of CD8+ T Cells Is a Signature of Experimental Cerebral Malaria. PLoS Pathog 2015; 11:e1005210. [PMID: 26562533 PMCID: PMC4643016 DOI: 10.1371/journal.ppat.1005210] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 09/16/2015] [Indexed: 12/18/2022] Open
Abstract
There is significant evidence that brain-infiltrating CD8+ T cells play a central role in the development of experimental cerebral malaria (ECM) during Plasmodium berghei ANKA infection of C57BL/6 mice. However, the mechanisms through which they mediate their pathogenic activity during malaria infection remain poorly understood. Utilizing intravital two-photon microscopy combined with detailed ex vivo flow cytometric analysis, we show that brain-infiltrating T cells accumulate within the perivascular spaces of brains of mice infected with both ECM-inducing (P. berghei ANKA) and non-inducing (P. berghei NK65) infections. However, perivascular T cells displayed an arrested behavior specifically during P. berghei ANKA infection, despite the brain-accumulating CD8+ T cells exhibiting comparable activation phenotypes during both infections. We observed T cells forming long-term cognate interactions with CX3CR1-bearing antigen presenting cells within the brains during P. berghei ANKA infection, but abrogation of this interaction by targeted depletion of the APC cells failed to prevent ECM development. Pathogenic CD8+ T cells were found to colocalize with rare apoptotic cells expressing CD31, a marker of endothelial cells, within the brain during ECM. However, cellular apoptosis was a rare event and did not result in loss of cerebral vasculature or correspond with the extensive disruption to its integrity observed during ECM. In summary, our data show that the arrest of T cells in the perivascular compartments of the brain is a unique signature of ECM-inducing malaria infection and implies an important role for this event in the development of the ECM-syndrome. Cerebral malaria is the most severe complication of Plasmodium falciparum infection. Utilizing the murine experimental model of cerebral malaria (ECM), it has been found that CD8+ T cells are a key immune cell type responsible for development of cerebral pathology during malaria infection. To identify how CD8+ T cells cause cerebral pathology during malaria infection, in this study we have performed detailed in vivo analysis (two photon imaging) of CD8+ T cells within the brains of mice infected with strains of malaria parasites that cause or do not cause ECM. We found that CD8+ T cells appear to accumulate in similar numbers and in comparable locations within the brains of mice infected with parasites that do or do not cause ECM. Importantly, however, brain accumulating CD8+ T cells displayed significantly different movement characteristics during the different infections. CD8+ T cells interacted with myeloid cells within the brain during infection with parasites causing ECM, but this association was not required for development of cerebral complications. Furthermore, our results suggest that CD8+ T cells do not cause ECM through the widespread killing of brain microvessel cells. The results in this study significantly improve our understanding of the ways through which CD8+ T cells can mediate cerebral pathology during malaria infection.
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Annane D, Sharshar T. Cognitive decline after sepsis. THE LANCET RESPIRATORY MEDICINE 2014; 3:61-9. [PMID: 25434614 DOI: 10.1016/s2213-2600(14)70246-2] [Citation(s) in RCA: 187] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The modern era of sepsis management is characterised by a growing number of patients who survive in the short term and are discharged from hospital. Increasing evidence suggests that these survivors exhibit long-term neurological sequelae, particularly substantial declines in cognitive function. The exact prevalence and outcomes of these neuropsychological sequelae are unclear. The mechanisms by which sepsis induces cognitive dysfunction probably include vascular injuries and neuroinflammation that are mediated by systemic metabolism disorders and overwhelming inflammation, a disrupted blood-brain barrier, oxidative stress, and severe microglial activation, particularly within the limbic system. Interventions targeting the blood-brain barrier, glial activation, and oxidative stress have shown promise in prevention of cognitive dysfunction in various experimental models of sepsis. The next step should be to translate these favourable effects into positive clinical results.
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Affiliation(s)
- Djillali Annane
- Department of Intensive Care Medicine, Raymond Poincaré Hospital, Assistance Publique-Hôpitaux de Paris, Garches, France; University of Versailles, Montigny le Bretonneux, France.
| | - Tarek Sharshar
- Department of Intensive Care Medicine, Raymond Poincaré Hospital, Assistance Publique-Hôpitaux de Paris, Garches, France; University of Versailles, Montigny le Bretonneux, France
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