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Angiotensin II type-1 receptor (AT 1R) regulates expansion, differentiation, and functional capacity of antigen-specific CD8 + T cells. Sci Rep 2016; 6:35997. [PMID: 27782175 PMCID: PMC5080615 DOI: 10.1038/srep35997] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 10/10/2016] [Indexed: 12/25/2022] Open
Abstract
Angiotensin II (Ang II) and its receptor AT1 (AT1R), an important effector axis of renin-angiotensin system (RAS), have been demonstrated to regulate T-cell responses. However, these studies characterized Ang II and AT1R effects using pharmacological tools, which do not target only Ang II/AT1R axis. The specific role of AT1R expressed by antigen-specific CD8+ T cells is unknown. Then we immunized transgenic mice expressing a T-cell receptor specific for SIINFEKL epitope (OT-I mice) with sporozoites of the rodent malaria parasite Plasmodium berghei expressing the cytotoxic epitope SIINFEKL. Early priming events after immunization were not affected but the expansion and contraction of AT1R-deficient (AT1R-/-) OT-I cells was decreased. Moreover, they seemed more activated, express higher levels of CTLA-4, PD-1, LAG-3, and have decreased functional capacity during the effector phase. Memory AT1R-/- OT-I cells exhibited higher IL-7Rα expression, activation, and exhaustion phenotypes but less cytotoxic capacity. Importantly, AT1R-/- OT-I cells show better control of blood parasitemia burden and ameliorate mice survival during lethal disease induced by blood-stage malaria. Our study reveals that AT1R in antigen-specific CD8+ T cells regulates expansion, differentiation, and function during effector and memory phases of the response against Plasmodium, which could apply to different infectious agents.
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52
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Absence of apolipoprotein E protects mice from cerebral malaria. Sci Rep 2016; 6:33615. [PMID: 27647324 PMCID: PMC5028887 DOI: 10.1038/srep33615] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 08/30/2016] [Indexed: 02/01/2023] Open
Abstract
Cerebral malaria claims the life of millions of people each year, particularly those of children, and is a major global public health problem. Thus, the identification of novel malaria biomarkers that could be utilized as diagnostic or therapeutic targets is becoming increasingly important. Using a proteomic approach, we previously identified unique biomarkers in the sera of malaria-infected individuals, including apolipoprotein E (ApoE). ApoE is the dominant apolipoprotein in the brain and has been implicated in several neurological disorders; therefore, we were interested in the potential role of ApoE in cerebral malaria. Here we report the first demonstration that cerebral malaria is markedly attenuated in ApoE−/− mice. The protection provided by the absence of ApoE was associated with decreased sequestration of parasites and T cells within the brain, and was determined to be independent from the involvement of ApoE receptors and from the altered lipid metabolism associated with the knock-out mice. Importantly, we demonstrated that treatment of mice with the ApoE antagonist heparin octasaccharide significantly decreased the incidence of cerebral malaria. Overall, our study indicates that the reduction of ApoE could be utilized in the development of therapeutic treatments aimed at mitigating the neuropathology of cerebral malaria.
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Chaves YO, da Costa AG, Pereira MLM, de Lacerda MVG, Coelho-Dos-Reis JG, Martins-Filho OA, Teixeira-Carvalho A, Malheiro A, Monteiro WM, Orlandi PP, Marinho CRF, Nogueira PA. Immune response pattern in recurrent Plasmodium vivax malaria. Malar J 2016; 15:445. [PMID: 27581163 PMCID: PMC5007810 DOI: 10.1186/s12936-016-1501-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 08/23/2016] [Indexed: 01/01/2023] Open
Abstract
Background Plasmodium vivax is the causative agent of human malaria of large geographic distribution, with 35 million cases annually. In Brazil, it is the most prevalent species, being responsible by around 70 % of the malaria cases. Methods A cross-sectional study was performed in Manaus (Amazonas, Brazil), including 36 adult patients with primary malaria, 19 with recurrent malaria, and 20 endemic controls. The ex vivo phenotypic features of circulating leukocyte subsets (CD4+ T-cells, CD8+ T-cells, NK, NKT, B, B1 and Treg cells) as well as the plasmatic cytokine profile (IL-2, IL-4, IL-6, IL-10, TNF and IFN-γ) were assessed, aiming at establishing patterns of immune response characteristic of primary malaria vs recurrent malaria as compared to endemic controls. Results The proportion of subjects with high levels of WBC was reduced in malaria patients as compared to the endemic control. Monocytes were diminished particularly in patients with primary malaria. The proportion of subjects with high levels of all lymphocyte subsets was decreased in all malaria groups, regardless their clinical status. Decreased proportion of subjects with high levels of CD4+ and CD8+ T-cells was found especially in the group of patients with recurrent malaria. Data analysis indicated significant increase in the proportion of the subjects with high plasmatic cytokine levels in both malaria groups, characterizing a typical cytokine storm. Recurrent malaria patients displayed the highest plasmatic IL-10 levels, that correlated directly with the CD4+/CD8+ T-cells ratio and the number of malaria episodes. Conclusion The findings confirm that the infection by the P. vivax causes a decrease in peripheral blood lymphocyte subsets, which is intensified in the cases of “recurrent malaria”. The unbalanced CD4+/CD8+ T-cells ratio, as well as increased IL-10 levels were correlated with the number of recurrent malaria episodes. These results suggest that the gradual remodelling of the immune response is dependent on the repeated exposure to the parasite, which involves a strict control of the immune response mediated by the CD4+/CD8+ T-cell unbalance and exacerbated IL-10 secretion. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1501-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yury Oliveira Chaves
- Instituto Leônidas e Maria Deane, Fundação Oswaldo Cruz (FIOCRUZ), Manaus, AM, Brazil
| | - Allyson Guimarães da Costa
- Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas (UEA), Manaus, AM, Brazil.,Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, AM, Brazil.,Departamento de Ensino e Pesquisa, Fundação Hospitalar de Hematologia e Hemoterapia do Amazonas (HEMOAM), Manaus, AM, Brazil
| | - Marcelo Luís Monteiro Pereira
- Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade de São Paulo (USP), São Paulo, SP, Brazil
| | - Marcus Vinícius Guimarães de Lacerda
- Instituto Leônidas e Maria Deane, Fundação Oswaldo Cruz (FIOCRUZ), Manaus, AM, Brazil.,Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas (UEA), Manaus, AM, Brazil.,Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, AM, Brazil
| | - Jordana Grazziela Coelho-Dos-Reis
- Grupo Integrado de Pesquisas em Biomarcadores de Diagnóstico e Monitoração, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, MG, Brazil
| | - Olindo Assis Martins-Filho
- Grupo Integrado de Pesquisas em Biomarcadores de Diagnóstico e Monitoração, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, MG, Brazil
| | - Andréa Teixeira-Carvalho
- Grupo Integrado de Pesquisas em Biomarcadores de Diagnóstico e Monitoração, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, MG, Brazil
| | - Adriana Malheiro
- Departamento de Ensino e Pesquisa, Fundação Hospitalar de Hematologia e Hemoterapia do Amazonas (HEMOAM), Manaus, AM, Brazil.,Programa de Pós-Graduação em Imunologia Básica e Aplicada, Universidade Federal do Amazonas (UFAM), Manaus, AM, Brazil
| | - Wuelton Marcelo Monteiro
- Programa de Pós-Graduação em Medicina Tropical, Universidade do Estado do Amazonas (UEA), Manaus, AM, Brazil.,Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, AM, Brazil
| | | | - Claudio Romero Farias Marinho
- Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade de São Paulo (USP), São Paulo, SP, Brazil
| | - Paulo Afonso Nogueira
- Instituto Leônidas e Maria Deane, Fundação Oswaldo Cruz (FIOCRUZ), Manaus, AM, Brazil.
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54
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Establishment of a murine model of cerebral malaria in KunMing mice infected with Plasmodium berghei ANKA. Parasitology 2016; 143:1672-80. [PMID: 27574013 DOI: 10.1017/s0031182016001475] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Malaria remains one of the most devastating diseases. Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection resulting in high mortality and morbidity worldwide. Analysis of precise mechanisms of CM in humans is difficult for ethical reasons and animal models of CM have been employed to study malaria pathogenesis. Here, we describe a new experimental cerebral malaria (ECM) model with Plasmodium berghei ANKA infection in KunMing (KM) mice. KM mice developed ECM after blood-stage or sporozoites infection, and the development of ECM in KM mice has a dose-dependent relationship with sporozoites inoculums. Histopathological findings revealed important features associated with ECM, including accumulation of mononuclear cells and red blood cells in brain microvascular, and brain parenchymal haemorrhages. Blood-brain barrier (BBB) examination showed that BBB disruption was present in infected KM mice when displaying clinical signs of CM. In vivo bioluminescent imaging experiment indicated that parasitized red blood cells accumulated in most vital organs including heart, lung, spleen, kidney, liver and brain. The levels of inflammatory cytokines interferon-gamma, tumour necrosis factor-alpha, interleukin (IL)-17, IL-12, IL-6 and IL-10 were all remarkably increased in KM mice infected with P. berghei ANKA. This study indicates that P. berghei ANKA infection in KM mice can be used as ECM model to extend further research on genetic, pharmacological and vaccine studies of CM.
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55
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Gupta P, Lai SM, Sheng J, Tetlak P, Balachander A, Claser C, Renia L, Karjalainen K, Ruedl C. Tissue-Resident CD169(+) Macrophages Form a Crucial Front Line against Plasmodium Infection. Cell Rep 2016; 16:1749-1761. [PMID: 27477286 DOI: 10.1016/j.celrep.2016.07.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 05/23/2016] [Accepted: 07/01/2016] [Indexed: 12/31/2022] Open
Abstract
Tissue macrophages exhibit diverse functions, ranging from the maintenance of tissue homeostasis, including clearance of senescent erythrocytes and cell debris, to modulation of inflammation and immunity. Their contribution to the control of blood-stage malaria remains unclear. Here, we show that in the absence of tissue-resident CD169(+) macrophages, Plasmodium berghei ANKA (PbA) infection results in significantly increased parasite sequestration, leading to vascular occlusion and leakage and augmented tissue deposition of the malarial pigment hemozoin. This leads to widespread tissue damage culminating in multiple organ inflammation. Thus, the capacity of CD169(+) macrophages to contain the parasite burden and its sequestration into different tissues and to limit infection-induced inflammation is crucial to mitigating Plasmodium infection and pathogenesis.
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Affiliation(s)
- Pravesh Gupta
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Si Min Lai
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Singapore; Singapore Immunology Network, Agency for Science, Technology and Research (A(∗)STAR), 8A Biomedical Grove, Singapore 138648, Singapore
| | - Jianpeng Sheng
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Piotr Tetlak
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Akhila Balachander
- Singapore Immunology Network, Agency for Science, Technology and Research (A(∗)STAR), 8A Biomedical Grove, Singapore 138648, Singapore
| | - Carla Claser
- Singapore Immunology Network, Agency for Science, Technology and Research (A(∗)STAR), 8A Biomedical Grove, Singapore 138648, Singapore
| | - Laurent Renia
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Singapore; Singapore Immunology Network, Agency for Science, Technology and Research (A(∗)STAR), 8A Biomedical Grove, Singapore 138648, Singapore
| | - Klaus Karjalainen
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Christiane Ruedl
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Singapore.
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56
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Brant F, Miranda AS, Esper L, Gualdrón-López M, Cisalpino D, de Souza DDG, Rachid MA, Tanowitz HB, Teixeira MM, Teixeira AL, Machado FS. Suppressor of cytokine signaling 2 modulates the immune response profile and development of experimental cerebral malaria. Brain Behav Immun 2016; 54:73-85. [PMID: 26765997 DOI: 10.1016/j.bbi.2016.01.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 12/23/2015] [Accepted: 01/04/2016] [Indexed: 11/18/2022] Open
Abstract
Plasmodium falciparum infection results in severe malaria in humans, affecting various organs, including the liver, spleen and brain, and resulting in high morbidity and mortality. The Plasmodium berghei ANKA (PbA) infection in mice closely recapitulates many aspects of human cerebral malaria (CM); thus, this model has been used to investigate the pathogenesis of CM. Suppressor of cytokine signaling 2 (SOCS2), an intracellular protein induced by cytokines and hormones, modulates the immune response, neural development, neurogenesis and neurotrophic pathways. However, the role of SOCS2 during CM remains unknown. SOCS2 knockout (SOCS2(-/-)) mice infected with PbA show an initial resistance to infection with reduced parasitemia and production of TNF, TGF-β, IL-12 and IL-17 in the brain. Interestingly, in the late phase of infection, SOCS2(-/-) mice display increased parasitemia and reduced Treg cell infiltration, associated with enhanced levels of Th1 and Th17 cells and related cytokines IL-17, IL-6, and TGF-β in the brain. A significant reduction in protective neurotrophic factors, such as glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF), was also observed. Moreover, the molecular alterations in the brain of infected SOCS2(-/-) mice were associated with anxiety-related behaviors and cognition impairment. Mechanistically, these results revealed enhanced nitric oxide (NO) production in PbA-infected SOCS2(-/-) mice, and the inhibition of NO synthesis through l-NAME led to a marked decrease in survival, the disruption of parasitemia control and more pronounced anxiety-like behavior. Treatment with l-NAME also shifted the levels of Th1, Th7 and Treg cells in the brains of infected SOCS2(-/-) mice to the background levels observed in infected WT, with remarkable exception of increased CD8(+)IFN(+) T cells and inflammatory monocytes. These results indicate that SOCS2 plays a dual role during PbA infection, being detrimental in the control of the parasite replication but crucial in the regulation of the immune response and production of neurotrophic factors. Here, we provided strong evidence of a critical relationship between SOCS2 and NO in the orchestration of the immune response and development of CM during PbA infection.
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Affiliation(s)
- Fatima Brant
- Program in Health Sciences: Infectious Diseases and Tropical Medicine, School of Medicine, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil; Department of Biochemistry and Immunology, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Aline S Miranda
- Program in Health Sciences: Infectious Diseases and Tropical Medicine, School of Medicine, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil; Department of Biochemistry and Immunology, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Lisia Esper
- Program in Health Sciences: Infectious Diseases and Tropical Medicine, School of Medicine, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil; Department of Biochemistry and Immunology, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Melisa Gualdrón-López
- Department of Biochemistry and Immunology, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Daniel Cisalpino
- Department of Microbiology, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Danielle da Gloria de Souza
- Department of Microbiology, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Milene Alvarenga Rachid
- Department of Pathology, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Herbert B Tanowitz
- Department of Pathology and Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Mauro Martins Teixeira
- Program in Health Sciences: Infectious Diseases and Tropical Medicine, School of Medicine, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil; Department of Biochemistry and Immunology, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Antônio Lucio Teixeira
- Program in Health Sciences: Infectious Diseases and Tropical Medicine, School of Medicine, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil; Department of Biochemistry and Immunology, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Fabiana Simão Machado
- Program in Health Sciences: Infectious Diseases and Tropical Medicine, School of Medicine, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil; Department of Biochemistry and Immunology, Institute of Biological Science, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
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57
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Ersching J, Vasconcelos JR, Ferreira CP, Caetano BC, Machado AV, Bruna–Romero O, Baron MA, Ferreira LRP, Cunha-Neto E, Rock KL, Gazzinelli RT, Rodrigues MM. The Combined Deficiency of Immunoproteasome Subunits Affects Both the Magnitude and Quality of Pathogen- and Genetic Vaccination-Induced CD8+ T Cell Responses to the Human Protozoan Parasite Trypanosoma cruzi. PLoS Pathog 2016; 12:e1005593. [PMID: 27128676 PMCID: PMC4851296 DOI: 10.1371/journal.ppat.1005593] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 04/01/2016] [Indexed: 11/18/2022] Open
Abstract
The β1i, β2i and β5i immunoproteasome subunits have an important role in defining the repertoire of MHC class I-restricted epitopes. However, the impact of combined deficiency of the three immunoproteasome subunits in the development of protective immunity to intracellular pathogens has not been investigated. Here, we demonstrate that immunoproteasomes play a key role in host resistance and genetic vaccination-induced protection against the human pathogen Trypanosoma cruzi (the causative agent of Chagas disease), immunity to which is dependent on CD8+ T cells and IFN-γ (the classical immunoproteasome inducer). We observed that infection with T. cruzi triggers the transcription of immunoproteasome genes, both in mice and humans. Importantly, genetically vaccinated or T. cruzi-infected β1i, β2i and β5i triple knockout (TKO) mice presented significantly lower frequencies and numbers of splenic CD8+ effector T cells (CD8+CD44highCD62Llow) specific for the previously characterized immunodominant (VNHRFTLV) H-2Kb-restricted T. cruzi epitope. Not only the quantity, but also the quality of parasite-specific CD8+ T cell responses was altered in TKO mice. Hence, the frequency of double-positive (IFN-γ+/TNF+) or single-positive (IFN-γ+) cells specific for the H-2Kb-restricted immunodominant as well as subdominant T. cruzi epitopes were higher in WT mice, whereas TNF single-positive cells prevailed among CD8+ T cells from TKO mice. Contrasting with their WT counterparts, TKO animals were also lethally susceptible to T. cruzi challenge, even after an otherwise protective vaccination with DNA and adenoviral vectors. We conclude that the immunoproteasome subunits are key determinants in host resistance to T. cruzi infection by influencing both the magnitude and quality of CD8+ T cell responses. CD8+ t lymphocytes are cells of the immune system that mediate control of intracellular infections by viruses, prokaryote as well as eukaryote pathogens. To confer protection, these lymphocytes need to be elicited by pathogen peptides that are presented in association with MHC class I molecules. The degradation of self and microbial proteins by catalytic domains of the cytosolic proteasome β1, β2 and β5 subunits is intimately linked to the generation of MHC class I-restricted epitopes, which in turn are important determinants of the kinetics, specificity and efficiency of CD8+ T cell-mediated immunity. Importantly, inflammatory stimuli trigger the expression of the inducible alternative β1i, β2i and β5i subunits that form the immunoproteasomes. The qualitative and quantitative importance of immunoproteasomes in generating CD8+ T cell epitopes has recently been demonstrated in mice that are simultaneously devoid of the β1i, β2i and β5i subunits. In this study, we explored the role of immunoproteasomes in host resistance to Trypanosoma cruzi, a protozoan parasite that causes Chagas disease. We found that β1i, β2i and β5i triply deficient mice have an impaired response of CD8+ T cells and are highly susceptible to primary infection with T. cruzi. We also demonstrated that host resistance induced by a genetic vaccine able to protect normal mice from T. cruzi challenge fails to do so in the immunoproteasome-deficient mice. Our study provides strong evidences that β1i, β2i and β5i immunoproteasome subunits are important determinants of both the magnitude and quality of CD8+ T cell responses as well as immune-mediated host resistance to a human pathogen.
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Affiliation(s)
- Jonatan Ersching
- Centro de Terapia Celular e Molecular and Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo - Escola Paulista de Medicina, São Paulo, São Paulo, Brazil
| | - José R. Vasconcelos
- Centro de Terapia Celular e Molecular and Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo - Escola Paulista de Medicina, São Paulo, São Paulo, Brazil
- Departamento de Biociências, Universidade Federal de São Paulo, Santos, São Paulo, Brazil
| | - Camila P. Ferreira
- Centro de Terapia Celular e Molecular and Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo - Escola Paulista de Medicina, São Paulo, São Paulo, Brazil
| | - Braulia C. Caetano
- Departments of Medicine and Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | | | - Oscar Bruna–Romero
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil
| | - Monique A. Baron
- Instituto do Coração (InCor), Faculdade de Medicina - Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Ludmila R. P. Ferreira
- Instituto do Coração (InCor), Faculdade de Medicina - Universidade de São Paulo, São Paulo, São Paulo, Brazil
- Universidade Santo Amaro, São Paulo, São Paulo, Brazil
| | - Edécio Cunha-Neto
- Instituto do Coração (InCor), Faculdade de Medicina - Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Kenneth L. Rock
- Departments of Medicine and Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Ricardo T. Gazzinelli
- Departments of Medicine and Pathology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Centro de Pesquisas René Rachou, FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- * E-mail:
| | - Maurício M. Rodrigues
- Centro de Terapia Celular e Molecular and Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo - Escola Paulista de Medicina, São Paulo, São Paulo, Brazil
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58
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De Niz M, Stanway RR, Wacker R, Keller D, Heussler VT. An ultrasensitive NanoLuc-based luminescence system for monitoring Plasmodium berghei throughout its life cycle. Malar J 2016; 15:232. [PMID: 27102897 PMCID: PMC4840902 DOI: 10.1186/s12936-016-1291-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 04/13/2016] [Indexed: 01/08/2023] Open
Abstract
Background Bioluminescence imaging is widely used for cell-based assays and animal imaging studies, both in biomedical research and drug development. Its main advantages include its high-throughput applicability, affordability, high sensitivity, operational simplicity, and quantitative outputs. In malaria research, bioluminescence has been used for drug discovery in vivo and in vitro, exploring host-pathogen interactions, and studying multiple aspects of Plasmodium biology. While the number of fluorescent proteins available for imaging has undergone a great expansion over the last two decades, enabling simultaneous visualization of multiple molecular and cellular events, expansion of available luciferases has lagged behind. The most widely used bioluminescent probe in malaria research is the Photinus pyralis firefly luciferase, followed by the more recently introduced Click-beetle and Renilla luciferases. Ultra-sensitive imaging of Plasmodium at low parasite densities has not been previously achieved. With the purpose of overcoming these challenges, a Plasmodium berghei line expressing the novel ultra-bright luciferase enzyme NanoLuc, called PbNLuc has been generated, and is presented in this work. Results NanoLuc shows at least 150 times brighter signal than firefly luciferase in vitro, allowing single parasite detection in mosquito, liver, and sexual and asexual blood stages. As a proof-of-concept, the PbNLuc parasites were used to image parasite development in the mosquito, liver and blood stages of infection, and to specifically explore parasite liver stage egress, and pre-patency period in vivo. Conclusions PbNLuc is a suitable parasite line for sensitive imaging of the entire Plasmodium life cycle. Its sensitivity makes it a promising line to be used as a reference for drug candidate testing, as well as the characterization of mutant parasites to explore the function of parasite proteins, host-parasite interactions, and the better understanding of Plasmodium biology. Since the substrate requirements of NanoLuc are different from those of firefly luciferase, dual bioluminescence imaging for the simultaneous characterization of two lines, or two separate biological processes, is possible, as demonstrated in this work.
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Affiliation(s)
- Mariana De Niz
- Institute of Cell Biology, University of Bern, 3012, Bern, Switzerland.
| | - Rebecca R Stanway
- Institute of Cell Biology, University of Bern, 3012, Bern, Switzerland
| | - Rahel Wacker
- Institute of Cell Biology, University of Bern, 3012, Bern, Switzerland
| | - Derya Keller
- Institute of Cell Biology, University of Bern, 3012, Bern, Switzerland
| | - Volker T Heussler
- Institute of Cell Biology, University of Bern, 3012, Bern, Switzerland
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59
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Liu M, Dickinson-Copeland C, Hassana S, Stiles JK. Plasmodium-infected erythrocytes (pRBC) induce endothelial cell apoptosis via a heme-mediated signaling pathway. DRUG DESIGN DEVELOPMENT AND THERAPY 2016; 10:1009-18. [PMID: 27042002 PMCID: PMC4780719 DOI: 10.2147/dddt.s96863] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Heme is cytotoxic to the plasmodium parasite, which converts it to an insoluble crystalline form called hemozoin (malaria pigment) in erythrocytes during replication. The increased serum levels of free heme cause tissue damage, activation of microvascular endothelial and glial cells, focal inflammation, activation of apoptotic pathways, and neuronal tissue damage. Several hypotheses have been proposed to explain how these causative factors exacerbate fatal malaria. However, none of them fully explain the detailed mechanisms leading to the high morbidity and mortality associated with malaria. We have previously reported that heme-induced brain microvascular endothelial cell (HBVEC) apoptosis is a major contributor to severe malaria pathogenesis. Here, we hypothesized that heme (at clinically relevant levels) induces inflammation and apoptosis in HBVEC, a process that is mediated by independent proinflammatory and proapoptotic signaling pathways. In this study, we determined the key signaling molecules associated with heme-mediated apoptosis in HBVEC in vitro using RT2 profiler polymerase chain reaction array technology and confirmed results using immunostaining techniques. While several expressed genes in HBVEC were altered upon heme stimulation, we determined that the apoptotic effects of heme were mediated through p73 (tumor protein p73). The results provide an opportunity to target heme-mediated apoptosis therapeutically in malaria-infected individuals.
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Affiliation(s)
- Mingli Liu
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Carmen Dickinson-Copeland
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Salifu Hassana
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Jonathan K Stiles
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, USA
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De SL, Stanisic DI, Rivera F, Batzloff MR, Engwerda C, Good MF. Plasmodium berghei bio-burden correlates with parasite lactate dehydrogenase: application to murine Plasmodium diagnostics. Malar J 2016; 15:3. [PMID: 26729268 PMCID: PMC4700574 DOI: 10.1186/s12936-015-1027-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 12/02/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The spectrum of techniques to detect malaria parasites in whole blood is limited to measuring parasites in circulation. One approach that is currently used to enumerate total parasite bio-burden involves the use of bio-luminescent parasites. As an alternative approach, this study describes the use of a commercial ELISA human parasite lactate dehydrogenase (pLDH) detection kit to estimate total parasite bio-burden in murine malaria models. METHODS The cross reactivity of pLDH in a commercial human malaria pLDH diagnostic kit was established in different components of blood for different murine malaria models. The use of pLDH as a measure of parasite bio-burden was evaluated by examining pLDH in relation to peripheral blood parasitaemia as determined by microscopy and calculating total parasite bio-burden using a bio-luminescent Plasmodium berghei ANKA luciferase parasite. RESULTS The pLDH antigen was detected in all four murine Plasmodium species and in all components of Plasmodium-infected blood. A significant correlation (r = 0.6922, P value <0.0001) was observed between total parasite bio-burden, measured as log average radiance, and concentration of pLDH units. CONCLUSIONS This high throughput assay is a suitable measure of total parasite bio-burden in murine malaria infections. Unlike existing methods, it permits the estimation of both circulating and sequestered parasites, allowing a more accurate assessment of parasite bio-burden.
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Affiliation(s)
- Sai Lata De
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia.
| | | | - Fabian Rivera
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.
| | - Michael R Batzloff
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia.
| | | | - Michael F Good
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia.
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61
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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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62
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Carneiro MBH, Lopes MEDM, Vaz LG, Sousa LMA, dos Santos LM, de Souza CC, Campos ACDA, Gomes DA, Gonçalves R, Tafuri WL, Vieira LQ. IFN-γ-Dependent Recruitment of CD4(+) T Cells and Macrophages Contributes to Pathogenesis During Leishmania amazonensis Infection. J Interferon Cytokine Res 2015; 35:935-47. [PMID: 26401717 PMCID: PMC4683564 DOI: 10.1089/jir.2015.0043] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 06/09/2015] [Indexed: 12/21/2022] Open
Abstract
Interferon gamma (IFN-γ) is a key factor in the protection of hosts against intracellular parasites. This cytokine induces parasite killing through nitric oxide and reactive oxygen species production by phagocytes. Surprisingly, during Leishmania amazonensis infection, IFN-γ plays controversial roles. During in vitro infections, IFN-γ induces the proliferation of the amastigote forms of L. amazonensis. However, this cytokine is not essential at the beginning of an in vivo infection. It is not clear why IFN-γ does not mediate protection during the early stages of infection. Thus, the aim of our study was to investigate the role of IFN-γ during L. amazonensis infection. We infected IFN-γ(-/-) mice in the footpad and followed the development of leishmaniasis in these mice compared with that in WT mice. CD4(+) T lymphocytes and macrophages migrated earlier to the site of infection in the WT mice, and the earlier migration of these 2 cell types was associated with lesion development and parasite growth, respectively. These differences in the infiltrate populations were explained by the increased expression of chemokines in the lesions of the WT mice. Thus, we propose that IFN-γ plays a dual role during L. amazonensis infection; it is an important inducer of effector mechanisms, particularly through inducible nitric oxide synthase expression, and conversely, it is a mediator of inflammation and pathogenesis through the induction of the expression of chemokines. Our data provided evidence for a pathogenic effect of IFN-γ production during leishmaniasis that was previously unknown.
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Affiliation(s)
- Matheus Batista Heitor Carneiro
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Mateus Eustáquio de Moura Lopes
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Leonardo Gomes Vaz
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Louisa Maria Andrade Sousa
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Liliane Martins dos Santos
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Carolina Carvalho de Souza
- Departamento de Patologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Ana Carolina de Angelis Campos
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Dawidson Assis Gomes
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Ricardo Gonçalves
- Departamento de Patologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Wagner Luiz Tafuri
- Departamento de Patologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Leda Quercia Vieira
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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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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Suppression of CD4+ Effector Responses by Naturally Occurring CD4+ CD25+ Foxp3+ Regulatory T Cells Contributes to Experimental Cerebral Malaria. Infect Immun 2015; 84:329-38. [PMID: 26553468 DOI: 10.1128/iai.00717-15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 11/02/2015] [Indexed: 11/20/2022] Open
Abstract
The role of naturally occurring CD4(+) CD25(+) Foxp3(+) regulatory T cells (nTreg) in the pathogenesis of cerebral malaria (CM), which involves both pathogenic T cell responses and parasite sequestration in the brain, is still unclear. To assess the contribution and dynamics of nTreg during the neuropathogenesis, we unbalanced the ratio between nTreg and naive CD4(+) T cells in an attenuated model of Plasmodium berghei ANKA-induced experimental CM (ECM) by using a selective cell enrichment strategy. We found that nTreg adoptive transfer accelerated the onset and increased the severity of CM in syngeneic C57BL/6 (B6) P. berghei ANKA-infected mice without affecting the level of parasitemia. In contrast, naive CD4(+) T cell enrichment prevented CM and promoted parasite clearance. Furthermore, early during the infection nTreg expanded in the spleen but did not efficiently migrate to the site of neuroinflammation, suggesting that nTreg exert their pathogenic action early in the spleen by suppressing the protective naive CD4(+) T cell response to P. berghei ANKA infection in vivo in both CM-susceptible (B6) and CM-resistant (B6-CD4(-/-)) mice. However, their sole transfer was not sufficient to restore CM susceptibility in two CM-resistant congenic strains tested. Altogether, these results demonstrate that nTreg are activated and functional during P. berghei ANKA infection and that they contribute to the pathogenesis of CM. They further suggest that nTreg may represent an early target for the modulation of the immune response to malaria.
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65
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Sahu PK, Satpathi S, Behera PK, Mishra SK, Mohanty S, Wassmer SC. Pathogenesis of cerebral malaria: new diagnostic tools, biomarkers, and therapeutic approaches. Front Cell Infect Microbiol 2015; 5:75. [PMID: 26579500 PMCID: PMC4621481 DOI: 10.3389/fcimb.2015.00075] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 10/05/2015] [Indexed: 12/28/2022] Open
Abstract
Cerebral malaria is a severe neuropathological complication of Plasmodium falciparum infection. It results in high mortality and post-recovery neuro-cognitive disorders in children, even after appropriate treatment with effective anti-parasitic drugs. While the complete landscape of the pathogenesis of cerebral malaria still remains to be elucidated, numerous innovative approaches have been developed in recent years in order to improve the early detection of this neurological syndrome and, subsequently, the clinical care of affected patients. In this review, we briefly summarize the current understanding of cerebral malaria pathogenesis, compile the array of new biomarkers and tools available for diagnosis and research, and describe the emerging therapeutic approaches to tackle this pathology effectively.
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Affiliation(s)
- Praveen K Sahu
- Center for the Study of Complex Malaria in India, Ispat General Hospital Rourkela, India
| | | | | | - Saroj K Mishra
- Center for the Study of Complex Malaria in India, Ispat General Hospital Rourkela, India
| | - Sanjib Mohanty
- Center for the Study of Complex Malaria in India, Ispat General Hospital Rourkela, India
| | - Samuel Crocodile Wassmer
- Department of Microbiology, New York University School of Medicine New York, NY, USA ; Department of Pathology, The University of Sydney Sydney, NSW, Australia
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66
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Matar CG, Jacobs NT, Speck SH, Lamb TJ, Moormann AM. Does EBV alter the pathogenesis of malaria? Parasite Immunol 2015; 37:433-45. [DOI: 10.1111/pim.12212] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 05/20/2015] [Indexed: 02/06/2023]
Affiliation(s)
- C. G. Matar
- Department of Microbiology and Immunology; Emory University School of Medicine; Atlanta GA USA
| | - N. T. Jacobs
- Department of Pediatrics; Emory University School of Medicine; Atlanta GA USA
| | - S. H. Speck
- Department of Microbiology and Immunology; Emory University School of Medicine; Atlanta GA USA
- Emory Vaccine Center; Emory University; Atlanta GA USA
| | - T. J. Lamb
- Department of Pediatrics; Emory University School of Medicine; Atlanta GA USA
| | - A. M. Moormann
- Program in Molecular Medicine; University of Massachusetts Medical School; Worcester MA USA
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67
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Simultaneously targeting inflammatory response and parasite sequestration in brain to treat Experimental Cerebral Malaria. Sci Rep 2015; 5:12671. [PMID: 26227888 PMCID: PMC4521148 DOI: 10.1038/srep12671] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 07/01/2015] [Indexed: 11/08/2022] Open
Abstract
Malaria afflicts around 200 million people annually, with a mortality number close to 600,000. The mortality rate in Human Cerebral Malaria (HCM) is unacceptably high (15–20%), despite the availability of artemisinin-based therapy. An effective adjunct therapy is urgently needed. Experimental Cerebral Malaria (ECM) in mice manifests many of the neurological features of HCM. Migration of T cells and parasite-infected RBCs (pRBCs) into the brain are both necessary to precipitate the disease. We have been able to simultaneously target both these parameters of ECM. Curcumin alone was able to reverse all the parameters investigated in this study that govern inflammatory responses, CD8+ T cell and pRBC sequestration into the brain and blood brain barrier (BBB) breakdown. But the animals eventually died of anemia due to parasite build-up in blood. However, arteether-curcumin (AC) combination therapy even after the onset of symptoms provided complete cure. AC treatment is a promising therapeutic option for HCM.
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68
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Activated Brain Endothelial Cells Cross-Present Malaria Antigen. PLoS Pathog 2015; 11:e1004963. [PMID: 26046849 PMCID: PMC4457820 DOI: 10.1371/journal.ppat.1004963] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 05/19/2015] [Indexed: 12/31/2022] Open
Abstract
In the murine model of cerebral malaria caused by P. berghei ANKA (PbA), parasite-specific CD8+ T cells directly induce pathology and have long been hypothesized to kill brain endothelial cells that have internalized PbA antigen. We previously reported that brain microvessel fragments from infected mice cross-present PbA epitopes, using reporter cells transduced with epitope-specific T cell receptors. Here, we confirm that endothelial cells are the population responsible for cross-presentation in vivo, not pericytes or microglia. PbA antigen cross-presentation by primary brain endothelial cells in vitro confers susceptibility to killing by CD8+ T cells from infected mice. IFNγ stimulation is required for brain endothelial cross-presentation in vivo and in vitro, which occurs by a proteasome- and TAP-dependent mechanism. Parasite strains that do not induce cerebral malaria were phagocytosed and cross-presented less efficiently than PbA in vitro. The main source of antigen appears to be free merozoites, which were avidly phagocytosed. A human brain endothelial cell line also phagocytosed P. falciparum merozoites. Besides being the first demonstration of cross-presentation by brain endothelial cells, our results suggest that interfering with merozoite phagocytosis or antigen processing may be effective strategies for cerebral malaria intervention.
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69
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Zhu X, Liu J, Feng Y, Pang W, Qi Z, Jiang Y, Shang H, Cao Y. Phenylhydrazine administration accelerates the development of experimental cerebral malaria. Exp Parasitol 2015; 156:1-11. [PMID: 26005191 DOI: 10.1016/j.exppara.2015.05.011] [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: 09/09/2014] [Revised: 05/12/2015] [Accepted: 05/18/2015] [Indexed: 01/13/2023]
Abstract
Phenylhydrazine (PHZ) treatment is generally used to enhance parasitemia in infected mice models. Transient reticulocytosis is commonly observed in iron-deficient anemic hosts after treatment with iron supplementation, and is also associated with short-term hemolysis caused by PHZ treatment. In this study, we investigated the relationship between reticulocytosis and cerebral malaria (CM) in a murine model induced by PHZ administration before Plasmodium berghei ANKA (PbA) infection. Mortality and parasitemia were checked daily. Pro-inflammatory cytokines and IL-10 were quantified by ELISA. The expression of CXCL9, CXCL10, CCL5, and CXCR3 mRNAs was determined by real-time PCR. Brain sequestration of CD4(+) and CD8(+) T cells and populations of splenic Th1 CD4(+) T cells, dendritic cells (DCs), CD11b(+) Gr1(+) cells, and regulatory T cells (Tregs) were assessed by FACS. PHZ administration dramatically increased parasitemia from day 3 to day 5 post infection (p.i.) compared with the untreated control infected mice group; also, CM developed at day 5 p.i., compared with day 7 p.i. in untreated control infected mice, as well as significantly decreased blood-brain barrier function (P < 0.001). PHZ administration during PbA infection significantly increased the expression of CXCL9 (P <0.05) and VCAM-1 (P <0.001) in the brain, increased the expression of CXCL10, CCL5 and CXCR3, and significantly increased the recruitment of CD4(+) and CD8(+) T cells (P <0.001 and P <0.01, respectively) as well as CD11b(+) Gr1(+) cells to the brain. In addition, PHZ administration significantly increased the numbers of IL-12-secreting DCs at days 3 and 5 p.i. compared to those of untreated control infected mice (P <0.001 and P <0.01, respectively). Consequently, the activation of CD4(+) T cells, especially the expansion of the Th1 subset (P <0.05), was significantly and dramatically enhanced and was accompanied by marked increases in the production of protein and/or mRNA of the Th1-type pro-inflammatory mediators, IFN-γ and TNF-α (P <0.01 for both for protein; P <0.05 for TNF-α mRNA). Our results suggest that, compared to healthy individuals, people suffering from reticulocytosis may be more susceptible to severe malaria infection in malaria endemic areas. This has implications for the most appropriate selection of treatment, which may also cause reticulocytosis in patients living in such areas.
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Affiliation(s)
- Xiaotong Zhu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110001, China
| | - Jun Liu
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110001, China
| | - Yonghui Feng
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110001, China
| | - Wei Pang
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110001, China
| | - Zanmei Qi
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110001, China
| | - Yongjun Jiang
- Department of Laboratory Medicine, the First Hospital of China Medical University, Shenyang, Liaoning, China; The Key Laboratory of AIDS Immunology of Ministry of Health, the First Hospitol of China Medical University, Shenyang, Liaoning, China
| | - Hong Shang
- Department of Laboratory Medicine, the First Hospital of China Medical University, Shenyang, Liaoning, China; The Key Laboratory of AIDS Immunology of Ministry of Health, the First Hospitol of China Medical University, Shenyang, Liaoning, China
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110001, China.
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70
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Siciliano G, Alano P. Enlightening the malaria parasite life cycle: bioluminescent Plasmodium in fundamental and applied research. Front Microbiol 2015; 6:391. [PMID: 26029172 PMCID: PMC4426725 DOI: 10.3389/fmicb.2015.00391] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/16/2015] [Indexed: 12/31/2022] Open
Abstract
The unicellular protozoan parasites of the genus Plasmodium impose on human health worldwide the enormous burden of malaria. The possibility to genetically modify several species of malaria parasites represented a major advance in the possibility to elucidate their biology and is now turning laboratory lines of transgenic Plasmodium into precious weapons to fight malaria. Amongst the various genetically modified plasmodia, transgenic parasite lines expressing bioluminescent reporters have been essential to unveil mechanisms of parasite gene expression and to develop in vivo imaging approaches in mouse malaria models. Mainly the human malaria parasite Plasmodium falciparum and the rodent parasite P. berghei have been engineered to express bioluminescent reporters in almost all the developmental stages of the parasite along its complex life cycle between the insect and the vertebrate hosts. Plasmodium lines expressing conventional and improved luciferase reporters are now gaining a central role to develop cell based assays in the much needed search of new antimalarial drugs and to open innovative approaches for both fundamental and applied research in malaria.
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Affiliation(s)
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di SanitàRome, Italy
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71
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Khoury DS, Cromer D, Best SE, James KR, Sebina I, Haque A, Davenport MP. Reduced erythrocyte susceptibility and increased host clearance of young parasites slows Plasmodium growth in a murine model of severe malaria. Sci Rep 2015; 5:9412. [PMID: 25944649 PMCID: PMC5386191 DOI: 10.1038/srep09412] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 03/02/2015] [Indexed: 12/23/2022] Open
Abstract
The best correlate of malaria severity in human Plasmodium falciparum (Pf) infection is the total parasite load. Pf-infected humans could control parasite loads by two mechanisms, either decreasing parasite multiplication, or increasing parasite clearance. However, few studies have directly measured these two mechanisms in vivo. Here, we have directly quantified host clearance of parasites during Plasmodium infection in mice. We transferred labelled red blood cells (RBCs) from Plasmodium infected donors into uninfected and infected recipients, and tracked the fate of donor parasites by frequent blood sampling. We then applied age-based mathematical models to characterise parasite clearance in the recipient mice. Our analyses revealed an increased clearance of parasites in infected animals, particularly parasites of a younger developmental stage. However, the major decrease in parasite multiplication in infected mice was not mediated by increased clearance alone, but was accompanied by a significant reduction in the susceptibility of RBCs to parasitisation.
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Affiliation(s)
- David S Khoury
- Complex Systems in Biology Group, Centre for Vascular Research, UNSW Australia, Kensington NSW 2052, Australia
| | - Deborah Cromer
- Complex Systems in Biology Group, Centre for Vascular Research, UNSW Australia, Kensington NSW 2052, Australia
| | - Shannon E Best
- Malaria Immunology Laboratory, QIMR Berghofer Medical Research Institute, Herston, Brisbane QLD 4006, Australia
| | - Kylie R James
- Malaria Immunology Laboratory, QIMR Berghofer Medical Research Institute, Herston, Brisbane QLD 4006, Australia
| | - Ismail Sebina
- Malaria Immunology Laboratory, QIMR Berghofer Medical Research Institute, Herston, Brisbane QLD 4006, Australia
| | - Ashraful Haque
- Malaria Immunology Laboratory, QIMR Berghofer Medical Research Institute, Herston, Brisbane QLD 4006, Australia
| | - Miles P Davenport
- Complex Systems in Biology Group, Centre for Vascular Research, UNSW Australia, Kensington NSW 2052, Australia
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72
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Disruption of Parasite hmgb2 Gene Attenuates Plasmodium berghei ANKA Pathogenicity. Infect Immun 2015; 83:2771-84. [PMID: 25916985 DOI: 10.1128/iai.03129-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 04/19/2015] [Indexed: 12/20/2022] Open
Abstract
Eukaryotic high-mobility-group-box (HMGB) proteins are nuclear factors involved in chromatin remodeling and transcription regulation. When released into the extracellular milieu, HMGB1 acts as a proinflammatory cytokine that plays a central role in the pathogenesis of several immune-mediated inflammatory diseases. We found that the Plasmodium genome encodes two genuine HMGB factors, Plasmodium HMGB1 and HMGB2, that encompass, like their human counterparts, a proinflammatory domain. Given that these proteins are released from parasitized red blood cells, we then hypothesized that Plasmodium HMGB might contribute to the pathogenesis of experimental cerebral malaria (ECM), a lethal neuroinflammatory syndrome that develops in C57BL/6 (susceptible) mice infected with Plasmodium berghei ANKA and that in many aspects resembles human cerebral malaria elicited by P. falciparum infection. The pathogenesis of experimental cerebral malaria was suppressed in C57BL/6 mice infected with P. berghei ANKA lacking the hmgb2 gene (Δhmgb2 ANKA), an effect associated with a reduction of histological brain lesions and with lower expression levels of several proinflammatory genes. The incidence of ECM in pbhmgb2-deficient mice was restored by the administration of recombinant PbHMGB2. Protection from experimental cerebral malaria in Δhmgb2 ANKA-infected mice was associated with reduced sequestration in the brain of CD4(+) and CD8(+) T cells, including CD8(+) granzyme B(+) and CD8(+) IFN-γ(+) cells, and, to some extent, neutrophils. This was consistent with a reduced parasite sequestration in the brain, lungs, and spleen, though to a lesser extent than in wild-type P. berghei ANKA-infected mice. In summary, Plasmodium HMGB2 acts as an alarmin that contributes to the pathogenesis of cerebral malaria.
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Phosphatidylinositol 3-Kinase γ is required for the development of experimental cerebral malaria. PLoS One 2015; 10:e0119633. [PMID: 25775137 PMCID: PMC4361544 DOI: 10.1371/journal.pone.0119633] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 02/01/2015] [Indexed: 11/19/2022] Open
Abstract
Experimental cerebral malaria (ECM) is characterized by a strong immune response, with leukocyte recruitment, blood-brain barrier breakdown and hemorrhage in the central nervous system. Phosphatidylinositol 3-kinase γ (PI3Kγ) is central in signaling diverse cellular functions. Using PI3Kγ-deficient mice (PI3Kγ-/-) and a specific PI3Kγ inhibitor, we investigated the relevance of PI3Kγ for the outcome and the neuroinflammatory process triggered by Plasmodium berghei ANKA (PbA) infection. Infected PI3Kγ-/- mice had greater survival despite similar parasitemia levels in comparison with infected wild type mice. Histopathological analysis demonstrated reduced hemorrhage, leukocyte accumulation and vascular obstruction in the brain of infected PI3Kγ-/- mice. PI3Kγ deficiency also presented lower microglial activation (Iba-1+ reactive microglia) and T cell cytotoxicity (Granzyme B expression) in the brain. Additionally, on day 6 post-infection, CD3+CD8+ T cells were significantly reduced in the brain of infected PI3Kγ-/- mice when compared to infected wild type mice. Furthermore, expression of CD44 in CD8+ T cell population in the brain tissue and levels of phospho-IkB-α in the whole brain were also markedly lower in infected PI3Kγ-/- mice when compared with infected wild type mice. Finally, AS605240, a specific PI3Kγ inhibitor, significantly delayed lethality in infected wild type mice. In brief, our results indicate a pivotal role for PI3Kγ in the pathogenesis of ECM.
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74
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Howland SW, Claser C, Poh CM, Gun SY, Rénia L. Pathogenic CD8+ T cells in experimental cerebral malaria. Semin Immunopathol 2015; 37:221-31. [PMID: 25772948 DOI: 10.1007/s00281-015-0476-6] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 03/01/2015] [Indexed: 11/26/2022]
Abstract
Cerebral malaria (CM) is one the major complications occurring during malaria infection. The mechanisms leading to this syndrome are still not completely understood. Although it is clear that parasite sequestration is the key initiation factor, the downstream pathological processes are still highly debated. The experimental cerebral malaria (ECM) model, in which susceptible mice are infected with Plasmodium berghei ANKA, has led to the identification of CD8(+) T cells as the major mediator of ECM death. In this review, we discuss the recent advances and future developments in the understanding of the role of CD8(+) T cells in CM.
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Affiliation(s)
- Shanshan Wu Howland
- Singapore Immunology Network, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
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75
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Van Den Ham KM, Shio MT, Rainone A, Fournier S, Krawczyk CM, Olivier M. Iron prevents the development of experimental cerebral malaria by attenuating CXCR3-mediated T cell chemotaxis. PLoS One 2015; 10:e0118451. [PMID: 25768944 PMCID: PMC4359107 DOI: 10.1371/journal.pone.0118451] [Citation(s) in RCA: 8] [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: 09/11/2014] [Accepted: 01/20/2015] [Indexed: 12/16/2022] Open
Abstract
Cerebral malaria is a severe neurological complication of Plasmodium falciparum infection. Previous studies have suggested that iron overload can suppress the generation of a cytotoxic immune response; however, the effect of iron on experimental cerebral malaria (ECM) is yet unknown. Here we determined that the incidence of ECM was markedly reduced in mice treated with iron dextran. Protection was concomitant with a significant decrease in the sequestration of CD4+ and CD8+ T cells within the brain. CD4+ T cells demonstrated markedly decreased CXCR3 expression and had reduced IFNγ-responsiveness, as indicated by mitigated expression of IFNγR2 and T-bet. Additional analysis of the splenic cell populations indicated that parenteral iron supplementation was also associated with a decrease in NK cells and increase in regulatory T cells. Altogether, these results suggest that iron is able to inhibit ECM pathology by attenuating the capacity of T cells to migrate to the brain.
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MESH Headings
- Animals
- Brain/drug effects
- Brain/immunology
- Brain/metabolism
- CD4-Positive T-Lymphocytes/drug effects
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- CD8-Positive T-Lymphocytes/drug effects
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/metabolism
- Chemotaxis, Leukocyte/drug effects
- Chemotaxis, Leukocyte/immunology
- Disease Models, Animal
- Female
- Interferon-gamma/immunology
- Interferon-gamma/metabolism
- Iron/immunology
- Iron/pharmacology
- Killer Cells, Natural/drug effects
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Malaria, Cerebral/etiology
- Malaria, Cerebral/immunology
- Malaria, Cerebral/metabolism
- Malaria, Cerebral/prevention & control
- Malaria, Falciparum/complications
- Malaria, Falciparum/immunology
- Malaria, Falciparum/metabolism
- Mice
- Mice, Inbred C57BL
- Plasmodium falciparum/immunology
- Receptors, CXCR3/immunology
- Receptors, CXCR3/metabolism
- T-Box Domain Proteins/immunology
- T-Box Domain Proteins/metabolism
- T-Lymphocytes, Regulatory/drug effects
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/metabolism
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Affiliation(s)
- Kristin M. Van Den Ham
- Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
- McGill International TB Centre, Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Marina Tiemi Shio
- Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
- McGill International TB Centre, Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
| | - Anthony Rainone
- Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
| | - Sylvie Fournier
- Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
| | - Connie M. Krawczyk
- Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
| | - Martin Olivier
- Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada
- McGill International TB Centre, Research Institute of the McGill University Health Centre, Montréal, Québec, Canada
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76
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Dietary restriction protects against experimental cerebral malaria via leptin modulation and T-cell mTORC1 suppression. Nat Commun 2015; 6:6050. [PMID: 25636003 PMCID: PMC4313624 DOI: 10.1038/ncomms7050] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 12/06/2014] [Indexed: 02/06/2023] Open
Abstract
Host nutrition can affect the outcome of parasitic diseases through metabolic effects on host immunity and/or the parasite. Here we show that modulation of mouse immunometabolism through brief restriction of food intake (dietary restriction, DR) prevents neuropathology in experimental cerebral malaria (ECM). While no effects are detected on parasite growth, DR reduces parasite accumulation in peripheral tissues including brain, and increases clearance in the spleen. Leptin, a host-derived adipokine linking appetite, energy balance and immune function, is required for ECM pathology and its levels are reduced upon DR. Recombinant leptin abrogates DR benefits, while pharmacological or genetic inhibition of leptin signaling protects against ECM. DR reduces mTORC1 activity in T cells, and this effect is abrogated upon leptin administration. Furthermore, mTORC1 inhibition with rapamycin prevents ECM pathology. Our results suggest that leptin and mTORC1 provide a novel mechanistic link between nutrition, immunometabolism and ECM pathology, with potential therapeutic implications for cerebral malaria.
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77
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Malaria induces anemia through CD8+ T cell-dependent parasite clearance and erythrocyte removal in the spleen. mBio 2015; 6:mBio.02493-14. [PMID: 25604792 PMCID: PMC4324318 DOI: 10.1128/mbio.02493-14] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED Severe malarial anemia (SMA) in semi-immune individuals eliminates both infected and uninfected erythrocytes and is a frequent fatal complication. It is proportional not to circulating parasitemia but total parasite mass (sequestered) in the organs. Thus, immune responses that clear parasites in organs may trigger changes leading to anemia. Here, we use an outbred-rat model where increasing parasite removal in the spleen escalated uninfected-erythrocyte removal. Splenic parasite clearance was associated with activated CD8(+) T cells, immunodepletion of which prevented parasite clearance. CD8(+) T cell repletion and concomitant reduction of the parasite load was associated with exacerbated (40 to 60%) hemoglobin loss and changes in properties of uninfected erythrocytes. Together, these data suggest that CD8(+) T cell-dependent parasite clearance causes erythrocyte removal in the spleen and thus anemia. In children infected with the human malaria parasite Plasmodium falciparum, elevation of parasite biomass (not the number of circulating parasites) increased the odds ratio for SMA by 3.5-fold (95% confidence intervals [CI95%], 1.8- to 7.5-fold). CD8(+) T cell expansion/activation independently increased the odds ratio by 2.4-fold (CI95%, 1.0- to 5.7-fold). Concomitant increases in both conferred a 7-fold (CI95%, 1.9- to 27.4-fold)-greater risk for SMA. Together, these data suggest that CD8(+)-dependent parasite clearance may predispose individuals to uninfected-erythrocyte loss and SMA, thus informing severe disease diagnosis and strategies for vaccine development. IMPORTANCE Malaria is a major global health problem. Severe malaria anemia (SMA) is a complex disease associated with partial immunity. Rapid hemoglobin reductions of 20 to 50% are commonly observed and must be rescued by transfusion (which can carry a risk of HIV acquisition). The causes and risk factors of SMA remain poorly understood. Recent studies suggest that SMA is linked to parasite biomass sequestered in organs. This led us to investigate whether immune mechanisms that clear parasites in organs trigger anemia. In rats, erythropoiesis is largely restricted to the bone marrow, and critical aspects of the spleen expected to be important in anemia are similar to those in humans. Therefore, using a rat model, we show that severe anemia is caused through CD8(+) T cell-dependent parasite clearance and erythrocyte removal in the spleen. CD8 activation may also be a new risk factor for SMA in African children.
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78
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Nacer A, Movila A, Sohet F, Girgis NM, Gundra UM, Loke P, Daneman R, Frevert U. Experimental cerebral malaria pathogenesis--hemodynamics at the blood brain barrier. PLoS Pathog 2014; 10:e1004528. [PMID: 25474413 PMCID: PMC4256476 DOI: 10.1371/journal.ppat.1004528] [Citation(s) in RCA: 77] [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: 06/19/2014] [Accepted: 10/17/2014] [Indexed: 12/16/2022] Open
Abstract
Cerebral malaria claims the lives of over 600,000 African children every year. To better understand the pathogenesis of this devastating disease, we compared the cellular dynamics in the cortical microvasculature between two infection models, Plasmodium berghei ANKA (PbA) infected CBA/CaJ mice, which develop experimental cerebral malaria (ECM), and P. yoelii 17XL (PyXL) infected mice, which succumb to malarial hyperparasitemia without neurological impairment. Using a combination of intravital imaging and flow cytometry, we show that significantly more CD8(+) T cells, neutrophils, and macrophages are recruited to postcapillary venules during ECM compared to hyperparasitemia. ECM correlated with ICAM-1 upregulation on macrophages, while vascular endothelia upregulated ICAM-1 during ECM and hyperparasitemia. The arrest of large numbers of leukocytes in postcapillary and larger venules caused microrheological alterations that significantly restricted the venous blood flow. Treatment with FTY720, which inhibits vascular leakage, neurological signs, and death from ECM, prevented the recruitment of a subpopulation of CD45(hi) CD8(+) T cells, ICAM-1(+) macrophages, and neutrophils to postcapillary venules. FTY720 had no effect on the ECM-associated expression of the pattern recognition receptor CD14 in postcapillary venules suggesting that endothelial activation is insufficient to cause vascular pathology. Expression of the endothelial tight junction proteins claudin-5, occludin, and ZO-1 in the cerebral cortex and cerebellum of PbA-infected mice with ECM was unaltered compared to FTY720-treated PbA-infected mice or PyXL-infected mice with hyperparasitemia. Thus, blood brain barrier opening does not involve endothelial injury and is likely reversible, consistent with the rapid recovery of many patients with CM. We conclude that the ECM-associated recruitment of large numbers of activated leukocytes, in particular CD8(+) T cells and ICAM(+) macrophages, causes a severe restriction in the venous blood efflux from the brain, which exacerbates the vasogenic edema and increases the intracranial pressure. Thus, death from ECM could potentially occur as a consequence of intracranial hypertension.
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Affiliation(s)
- Adéla Nacer
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Alexandru Movila
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Fabien Sohet
- Department of Anatomy, University of California San Francisco, San Francisco, California, United States of America
| | - Natasha M. Girgis
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Uma Mahesh Gundra
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - P'ng Loke
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Richard Daneman
- Department of Anatomy, University of California San Francisco, San Francisco, California, United States of America
| | - Ute Frevert
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
- * E-mail:
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79
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Damage to the blood-brain barrier during experimental cerebral malaria results from synergistic effects of CD8+ T cells with different specificities. Infect Immun 2014; 82:4854-64. [PMID: 25156726 DOI: 10.1128/iai.02180-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CD8(+) T cells play a pathogenic role in the development of murine experimental cerebral malaria (ECM) induced by Plasmodium berghei ANKA (PbA) infection in C57BL/6 mice. Only a limited number of CD8(+) epitopes have been described. Here, we report the identification of a new epitope from the bergheilysin protein recognized by PbA-specific CD8(+) T cells. Induction and functionality of these specific CD8(+) T cells were investigated in parallel with previously reported epitopes, using new tools such as tetramers and reporter cell lines that were developed for this study. We demonstrate that CD8(+) T cells of diverse specificities induced during PbA infection share many characteristics. They express cytolytic markers (gamma interferon [IFN-γ], granzyme B) and chemokine receptors (CXCR3, CCR5) and damage the blood-brain barrier in vivo. Our earlier finding that brain microvessels in mice infected with PbA, but not with non-ECM-causing strains, cross-presented a shared epitope was generalizable to these additional epitopes. Suppressing the induction of specific CD8(+) T cells through tolerization with a high-dose peptide injection was unable to confer protection against ECM, suggesting that CD8(+) T cells of other specificities participate in this process. The tools that we developed can be used to further investigate the heterogeneity of CD8(+) T cell responses that are involved in ECM.
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80
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Hunt NH, Ball HJ, Hansen AM, Khaw LT, Guo J, Bakmiwewa S, Mitchell AJ, Combes V, Grau GER. Cerebral malaria: gamma-interferon redux. Front Cell Infect Microbiol 2014; 4:113. [PMID: 25177551 PMCID: PMC4133756 DOI: 10.3389/fcimb.2014.00113] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 07/30/2014] [Indexed: 11/13/2022] Open
Abstract
There are two theories that seek to explain the pathogenesis of cerebral malaria, the mechanical obstruction hypothesis and the immunopathology hypothesis. Evidence consistent with both ideas has accumulated from studies of the human disease and experimental models. Thus, some combination of these concepts seems necessary to explain the very complex pattern of changes seen in cerebral malaria. The interactions between malaria parasites, erythrocytes, the cerebral microvascular endothelium, brain parenchymal cells, platelets and microparticles need to be considered. One factor that seems able to knit together much of this complexity is the cytokine interferon-gamma (IFN-γ). In this review we consider findings from the clinical disease, in vitro models and the murine counterpart of human cerebral malaria in order to evaluate the roles played by IFN-γ in the pathogenesis of this often fatal and debilitating condition.
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Affiliation(s)
- Nicholas H Hunt
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Helen J Ball
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Anna M Hansen
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Loke T Khaw
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Jintao Guo
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Supun Bakmiwewa
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Andrew J Mitchell
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Valéry Combes
- Vascular Immunology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Georges E R Grau
- Vascular Immunology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
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81
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Pai S, Qin J, Cavanagh L, Mitchell A, El-Assaad F, Jain R, Combes V, Hunt NH, Grau GER, Weninger W. Real-time imaging reveals the dynamics of leukocyte behaviour during experimental cerebral malaria pathogenesis. PLoS Pathog 2014; 10:e1004236. [PMID: 25033406 PMCID: PMC4102563 DOI: 10.1371/journal.ppat.1004236] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 05/23/2014] [Indexed: 02/02/2023] Open
Abstract
During experimental cerebral malaria (ECM) mice develop a lethal neuropathological syndrome associated with microcirculatory dysfunction and intravascular leukocyte sequestration. The precise spatio-temporal context in which the intravascular immune response unfolds is incompletely understood. We developed a 2-photon intravital microscopy (2P-IVM)-based brain-imaging model to monitor the real-time behaviour of leukocytes directly within the brain vasculature during ECM. Ly6Chi monocytes, but not neutrophils, started to accumulate in the blood vessels of Plasmodium berghei ANKA (PbA)-infected MacGreen mice, in which myeloid cells express GFP, one to two days prior to the onset of the neurological signs (NS). A decrease in the rolling speed of monocytes, a measure of endothelial cell activation, was associated with progressive worsening of clinical symptoms. Adoptive transfer experiments with defined immune cell subsets in recombinase activating gene (RAG)-1-deficient mice showed that these changes were mediated by Plasmodium-specific CD8+ T lymphocytes. A critical number of CD8+ T effectors was required to induce disease and monocyte adherence to the vasculature. Depletion of monocytes at the onset of disease symptoms resulted in decreased lymphocyte accumulation, suggesting reciprocal effects of monocytes and T cells on their recruitment within the brain. Together, our studies define the real-time kinetics of leukocyte behaviour in the central nervous system during ECM, and reveal a significant role for Plasmodium-specific CD8+ T lymphocytes in regulating vascular pathology in this disease. Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection that takes a significant toll on human life. Blockage of the brain blood vessels contributes to the clinical signs of CM, however we know little about the precise pathological events that lead to this disease. To this end, studies in Plasmodium-infected mice, that also develop a similar fatal disease, have proven useful. These studies have revealed an important role for leukocytes not so much in protecting but rather promoting pathology in the brain. To better understand leukocyte behaviour during experimental CM, we established a brain-imaging model that allows us to ‘peek’ into the brain of living mice and watch immunological events as they unfold. We found that worsening of disease was accompanied by an accumulation of monocytes in the blood vessels. Monocyte accumulation was regulated by activated CD8+ T cells but only when present in critical numbers. Monocyte depletion resulted in reduced T cell trafficking to the brain, but this did not result in improved disease outcome. Our studies reveal the orchestration of leukocyte accumulation in real time during CM, and demonstrate that CD8+ T cells play a crucial role in promoting clinical signs in this disease.
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Affiliation(s)
- Saparna Pai
- Immune Imaging Laboratory, The Centenary Institute, Newtown, Sydney, New South Wales, Australia
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
- * E-mail: (SP); (WW)
| | - Jim Qin
- Immune Imaging Laboratory, The Centenary Institute, Newtown, Sydney, New South Wales, Australia
| | - Lois Cavanagh
- Immune Imaging Laboratory, The Centenary Institute, Newtown, Sydney, New South Wales, Australia
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Andrew Mitchell
- Immune Imaging Laboratory, The Centenary Institute, Newtown, Sydney, New South Wales, Australia
| | - Fatima El-Assaad
- Vascular Immunology Unit, Discipline of Pathology, Sydney Medical School, University of Sydney, Camperdown, Sydney, New South Wales, Australia
| | - Rohit Jain
- Immune Imaging Laboratory, The Centenary Institute, Newtown, Sydney, New South Wales, Australia
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Valery Combes
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
- Vascular Immunology Unit, Discipline of Pathology, Sydney Medical School, University of Sydney, Camperdown, Sydney, New South Wales, Australia
| | - Nicholas H. Hunt
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
- Molecular Immunopathology Unit, Discipline of Pathology, Sydney Medical School and Bosch Institute, University of Sydney, Camperdown, Sydney, New South Wales, Australia
| | - Georges E. R. Grau
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
- Vascular Immunology Unit, Discipline of Pathology, Sydney Medical School, University of Sydney, Camperdown, Sydney, New South Wales, Australia
| | - Wolfgang Weninger
- Immune Imaging Laboratory, The Centenary Institute, Newtown, Sydney, New South Wales, Australia
- Discipline of Dermatology, University of Sydney, Sydney, New South Wales, Australia
- Department of Dermatology, Royal Prince Alfred Hospital, Camperdown, Sydney, New South Wales, Australia
- * E-mail: (SP); (WW)
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82
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Gun SY, Claser C, Tan KSW, Rénia L. Interferons and interferon regulatory factors in malaria. Mediators Inflamm 2014; 2014:243713. [PMID: 25157202 PMCID: PMC4124246 DOI: 10.1155/2014/243713] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 06/18/2014] [Indexed: 12/29/2022] Open
Abstract
Malaria is one of the most serious infectious diseases in humans and responsible for approximately 500 million clinical cases and 500 thousand deaths annually. Acquired adaptive immune responses control parasite replication and infection-induced pathologies. Most infections are clinically silent which reflects on the ability of adaptive immune mechanisms to prevent the disease. However, a minority of these can become severe and life-threatening, manifesting a range of overlapping syndromes of complex origins which could be induced by uncontrolled immune responses. Major players of the innate and adaptive responses are interferons. Here, we review their roles and the signaling pathways involved in their production and protection against infection and induced immunopathologies.
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Affiliation(s)
- Sin Yee Gun
- Singapore Immunology Network, Agency for Science, Technology and Research (ASTAR), Singapore 138648
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228
| | - Carla Claser
- Singapore Immunology Network, Agency for Science, Technology and Research (ASTAR), Singapore 138648
| | - Kevin Shyong Wei Tan
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228
| | - Laurent Rénia
- Singapore Immunology Network, Agency for Science, Technology and Research (ASTAR), Singapore 138648
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228
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83
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Reduction of experimental cerebral malaria and its related proinflammatory responses by the novel liposome-based β-methasone nanodrug. BIOMED RESEARCH INTERNATIONAL 2014; 2014:292471. [PMID: 25126550 PMCID: PMC4121993 DOI: 10.1155/2014/292471] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/16/2014] [Accepted: 06/16/2014] [Indexed: 01/11/2023]
Abstract
Cerebral malaria (CM) is a severe complication of and a leading cause of death due to Plasmodium falciparum infection. CM is likely the result of interrelated events, including mechanical obstruction due to parasite sequestration in the microvasculature, and upregulation of Th1 immune responses. In parallel, blood-brain-barrier (BBB) breakdown and damage or death of microglia, astrocytes, and neurons occurs. We found that a novel formulation of a liposome-encapsulated glucocorticosteroid, β-methasone hemisuccinate (nSSL-BMS), prevents experimental cerebral malaria (ECM) in a murine model and creates a survival time-window, enabling administration of an antiplasmodial drug before severe anemia develops. nSSL-BMS treatment leads to lower levels of cerebral inflammation, expressed by altered levels of corresponding cytokines and chemokines. The results indicate the role of integrated immune responses in ECM induction and show that the new steroidal nanodrug nSSL-BMS reverses the balance between the Th1 and Th2 responses in malaria-infected mice so that the proinflammatory processes leading to ECM are prevented. Overall, because of the immunopathological nature of CM, combined immunomodulator/antiplasmodial treatment should be considered for prevention/treatment of human CM and long-term cognitive damage.
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84
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Targeting the olfactory bulb during experimental cerebral malaria. Trends Parasitol 2014; 30:375-6. [PMID: 24856292 DOI: 10.1016/j.pt.2014.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 05/07/2014] [Indexed: 11/23/2022]
Abstract
Malaria is responsible for over 500 million clinical cases and over 500000 deaths annually. Fatalities arise from a range of overlapping syndromes, such as cerebral malaria, whose pathogenesis is still incompletely understood. In a new study, Coban and colleagues provide new clues on the involvement of the olfactory bulb during experimental cerebral malaria in mice that open the way to testable hypotheses and potentially earlier intervention in humans.
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85
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Role of the aryl hydrocarbon receptor in the immune response profile and development of pathology during Plasmodium berghei Anka infection. Infect Immun 2014; 82:3127-40. [PMID: 24818665 DOI: 10.1128/iai.01733-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Infection with Plasmodium falciparum may result in severe disease affecting various organs, including liver, spleen, and brain, resulting in high morbidity and mortality. Plasmodium berghei Anka infection of mice recapitulates many features of severe human malaria. The aryl hydrocarbon receptor (AhR) is an intracellular receptor activated by ligands important in the modulation of the inflammatory response. We found that AhR-knockout (KO) mice infected with P. berghei Anka displayed increased parasitemia, earlier mortality, enhanced leukocyte-endothelial cell interactions in the brain microvasculature, and increased inflammation in brain (interleukin-17 [IL-17] and IL-6) and liver (gamma interferon [IFN-γ] and tumor necrosis factor alpha [TNF-α]) compared to infected wild-type (WT) mice. Infected AhR-KO mice also displayed a reduction in cytokines required for host resistance, including TNF-α, IL-1β, and IFN-γ, in the brain and spleen. Infection of AhR-KO mice resulted in an increase in T regulatory cells and transforming growth factor β, IL-6, and IL-17 in the brain. AhR modulated the basal expression of SOCS3 in spleen and brain, and P. berghei Anka infection resulted in enhanced expression of SOCS3 in brain, which was absent in infected AhR-KO mice. These data suggest that AhR-mediated control of SOCS3 expression is probably involved in the phenotype seen in infected AhR-KO mice. This is, to our knowledge, the first demonstration of a role for AhR in the pathogenesis of malaria.
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86
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Brugat T, Cunningham D, Sodenkamp J, Coomes S, Wilson M, Spence PJ, Jarra W, Thompson J, Scudamore C, Langhorne J. Sequestration and histopathology in Plasmodium chabaudi malaria are influenced by the immune response in an organ-specific manner. Cell Microbiol 2014; 16:687-700. [PMID: 24003897 PMCID: PMC4234010 DOI: 10.1111/cmi.12212] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 07/26/2013] [Accepted: 08/26/2013] [Indexed: 11/28/2022]
Abstract
Infection with the malaria parasite, Plasmodium, is associated with a strong inflammatory response and parasite cytoadhesion (sequestration) in several organs. Here, we have carried out a systematic study of sequestration and histopathology during infection of C57Bl/6 mice with Plasmodium chabaudi AS and determined the influence of the immune response. This parasite sequesters predominantly in liver and lung, but not in the brain, kidney or gut. Histopathological changes occur in multiple organs during the acute infection, but are not restricted to the organs where sequestration takes place. Adaptive immunity, and signalling through the IFNγ receptor increased sequestration and histopathology in the liver, but not in the lung, suggesting that there are differences in the adhesion molecules and/or parasite ligands utilized and mechanisms of pathogenesis in these two organs. Exacerbation of pro-inflammatory responses during infection by deletion of the il10 gene resultsin the aggravation of damage to lung and kidney irrespective of the degree of sequestration. The immune response therefore affected both sequestration and histopathology in an organ-specific manner. P. chabaudi AS provides a good model to investigate the influence of the host response on the sequestration and specific organ pathology, which is applicable to human malaria.
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Affiliation(s)
- Thibaut Brugat
- Division of Parasitology, MRC National Institute for Medical Research, London, NW7 1AA, UK
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87
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Tamura T, Akbari M, Kimura K, Kimura D, Yui K. Flt3 ligand treatment modulates parasitemia during infection with rodent malaria parasites via MyD88- and IFN-γ-dependent mechanisms. Parasite Immunol 2014; 36:87-99. [PMID: 24400637 DOI: 10.1111/pim.12085] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 10/21/2013] [Indexed: 12/13/2022]
Abstract
We previously showed that treatment of mice with the Flt3 ligand (Flt3L) prevents development of lethal experimental cerebral malaria and inhibits parasitemia during Plasmodium berghei ANKA (PbA) infection. In this study, we investigated the mechanisms underlying the reduction of parasitemia in Flt3L-treated mice. Studies using gene knockout mice and antibody treatment indicated that the anti-parasitemia effect of Flt3L was mediated by innate immune system and was dependent on MyD88, IFN-γ, IL-12 and natural killer (NK) cells. The number of NK cells and their ability to produce IFN-γ was enhanced in Flt3L-treated mice. Phagocytic activity of splenocytes was increased in Flt3L-treated mice after PbA infection when compared with that in untreated mice, and this activity was mainly mediated by the accumulation of F4/80(mid) CD11b(+) cells in the spleen. In both MyD88(-/-) and IFN-γ(-/-) mice, the proportion of F4/80(mid) CD11b(+) cells was not increased in the spleen of Flt3L-treated mice after infection. These correlations suggest that NK cells produce IFN-γ in Flt3L-treated mice, and accumulation of F4/80(mid) CD11b(+) cells in the spleen is promoted by an IFN-γ -dependent manner, culminating in the inhibition of parasitemia. These findings imply that Flt3L promotes effective innate immunity against malaria infection mediated by interplay among varieties of innate immune cells.
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Affiliation(s)
- T Tamura
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Sakamoto, Nagasaki, Japan; Global COE Program, Nagasaki University, Sakamoto, Nagasaki, Japan
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88
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Bakocevic N, Claser C, Yoshikawa S, Jones LA, Chew S, Goh CC, Malleret B, Larbi A, Ginhoux F, de Lafaille MC, Karasuyama H, Renia L, Ng LG. CD41 is a reliable identification and activation marker for murine basophils in the steady state and during helminth and malarial infections. Eur J Immunol 2014; 44:1823-34. [DOI: 10.1002/eji.201344254] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 01/29/2014] [Accepted: 02/27/2014] [Indexed: 01/21/2023]
Affiliation(s)
- Nadja Bakocevic
- Singapore Immunology Network (SIgN); Agency for Science Technology and Research (A*STAR); Biopolis Singapore
| | - Carla Claser
- Singapore Immunology Network (SIgN); Agency for Science Technology and Research (A*STAR); Biopolis Singapore
| | - Soichiro Yoshikawa
- Department of Immune Regulation; Tokyo Medical and Dental University Graduate School; Tokyo Japan
| | - Leigh Ann Jones
- Singapore Immunology Network (SIgN); Agency for Science Technology and Research (A*STAR); Biopolis Singapore
| | - Samantha Chew
- Singapore Immunology Network (SIgN); Agency for Science Technology and Research (A*STAR); Biopolis Singapore
| | - Chi Ching Goh
- Singapore Immunology Network (SIgN); Agency for Science Technology and Research (A*STAR); Biopolis Singapore
| | - Benoit Malleret
- Singapore Immunology Network (SIgN); Agency for Science Technology and Research (A*STAR); Biopolis Singapore
| | - Anis Larbi
- Singapore Immunology Network (SIgN); Agency for Science Technology and Research (A*STAR); Biopolis Singapore
| | - Florent Ginhoux
- Singapore Immunology Network (SIgN); Agency for Science Technology and Research (A*STAR); Biopolis Singapore
| | - Maria Curotto de Lafaille
- Singapore Immunology Network (SIgN); Agency for Science Technology and Research (A*STAR); Biopolis Singapore
| | - Hajime Karasuyama
- Department of Immune Regulation; Tokyo Medical and Dental University Graduate School; Tokyo Japan
| | - Laurent Renia
- Singapore Immunology Network (SIgN); Agency for Science Technology and Research (A*STAR); Biopolis Singapore
| | - Lai Guan Ng
- Singapore Immunology Network (SIgN); Agency for Science Technology and Research (A*STAR); Biopolis Singapore
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89
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Increased survival in B-cell-deficient mice during experimental cerebral malaria suggests a role for circulating immune complexes. mBio 2014; 5:e00949-14. [PMID: 24643866 PMCID: PMC3967524 DOI: 10.1128/mbio.00949-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The pathogenesis of malaria, an insect-borne disease that takes millions of lives every year, is still not fully understood. Complement receptor 1 (CR1) has been described as a receptor for Plasmodium falciparum, which causes cerebral malaria in humans. We investigated the role of CR1 in an experimental model of cerebral malaria. Transgenic mice expressing human CR1 (hCR1(+)) on erythrocytes were infected with Plasmodium berghei ANKA and developed cerebral malaria. No difference in survival was observed in hCR1(+) mice compared to wild-type mice following infection with P. berghei ANKA; however, hCR1 detection was significantly diminished on erythrocytes between days 7 and 10 postinfection. hCR1 levels returned to baseline by day 17 postinfection in surviving animals. Immunoblot assays revealed that total erythrocyte hCR1 levels were diminished, confirming that immune complexes in association with erythrocyte hCR1 were likely removed from erythrocytes in vivo by clearance following immune adherence. Decreases in hCR1 were completely dependent on C3 expression, as mice treated with cobra venom factor (which consumes and depletes C3) retained hCR1 on erythrocytes during C3 depletion through day 7; erythrocyte hCR1 decreases were observed only when C3 levels recovered on day 9. B-cell-deficient mice exhibit a marked increase in survival following infection with P. berghei ANKA, which suggests that immune complexes play a central role in the pathogenesis of experimental cerebral malaria. Together, our findings highlight the importance of complement and immune complexes in experimental cerebral malaria. IMPORTANCE Cerebral malaria is a deadly complication of infection with Plasmodium falciparum. Despite its high prevalence, relatively little is understood about its pathogenesis. We have determined that immune complexes are generated and deposited on erythrocytes specifically expressing human complement receptor 1 in a mouse model of cerebral malaria. We also provide evidence demonstrating the importance of immunoglobulins in the pathogenesis of cerebral malaria in mice. These findings may have important implications in human cerebral malaria.
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90
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Villarino N, Schmidt NW. CD8 + T Cell Responses to Plasmodium and Intracellular Parasites. ACTA ACUST UNITED AC 2014; 9:169-178. [PMID: 24741372 PMCID: PMC3983867 DOI: 10.2174/1573395509666131126232327] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 11/14/2013] [Accepted: 11/19/2013] [Indexed: 12/29/2022]
Abstract
Parasitic protozoa are major threats to human health affecting millions of people around the world. Control of these infections by the host immune system relies on a myriad of immunological mechanisms that includes both humoral and cellular immunity. CD8+ T cells contribute to the control of these parasitic infections in both animals and humans. Here, we will focus on the CD8+ T cell response against a subset of these protozoa: Plasmodium, Toxoplasma gondii, Leishmania and Trypanosoma cruzi, with an emphasis on experimental rodent systems. It is evident a complex interaction occurs between CD8+ T cells and the invading protozoa. A detailed understanding of how CD8+ T cells mediate protection should provide the basis for the development of effective vaccines that prevent and control infections by these parasites.
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Affiliation(s)
- Nicolas Villarino
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
| | - Nathan W Schmidt
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
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91
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Claser C, Malleret B, Peng K, Bakocevic N, Gun SY, Russell B, Ng LG, Rénia L. Rodent Plasmodium-infected red blood cells: Imaging their fates and interactions within their hosts. Parasitol Int 2014; 63:187-94. [DOI: 10.1016/j.parint.2013.07.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 06/30/2013] [Accepted: 07/15/2013] [Indexed: 10/26/2022]
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92
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Polimeni M, Prato M. Host matrix metalloproteinases in cerebral malaria: new kids on the block against blood-brain barrier integrity? Fluids Barriers CNS 2014; 11:1. [PMID: 24467887 PMCID: PMC3905658 DOI: 10.1186/2045-8118-11-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 01/24/2014] [Indexed: 12/23/2022] Open
Abstract
Cerebral malaria (CM) is a life-threatening complication of falciparum malaria, associated with high mortality rates, as well as neurological impairment in surviving patients. Despite disease severity, the etiology of CM remains elusive. Interestingly, although the Plasmodium parasite is sequestered in cerebral microvessels, it does not enter the brain parenchyma: so how does Plasmodium induce neuronal dysfunction? Several independent research groups have suggested a mechanism in which increased blood–brain barrier (BBB) permeability might allow toxic molecules from the parasite or the host to enter the brain. However, the reported severity of BBB damage in CM is variable depending on the model system, ranging from mild impairment to full BBB breakdown. Moreover, the factors responsible for increased BBB permeability are still unknown. Here we review the prevailing theories on CM pathophysiology and discuss new evidence from animal and human CM models implicating BBB damage. Finally, we will review the newly-described role of matrix metalloproteinases (MMPs) and BBB integrity. MMPs comprise a family of proteolytic enzymes involved in modulating inflammatory response, disrupting tight junctions, and degrading sub-endothelial basal lamina. As such, MMPs represent potential innovative drug targets for CM.
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Affiliation(s)
| | - Mauro Prato
- Dipartimento di Neuroscienze, Università di Torino, C,so Raffaello 30, 10125 Torino, Italy.
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93
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Toxoplasma gondii upregulates interleukin-12 to prevent Plasmodium berghei-induced experimental cerebral malaria. Infect Immun 2014; 82:1343-53. [PMID: 24396042 DOI: 10.1128/iai.01259-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
A chronic infection with the parasite Toxoplasma gondii has previously been shown to protect mice against subsequent viral, bacterial, or protozoal infections. Here we have shown that a chronic T. gondii infection can prevent Plasmodium berghei ANKA-induced experimental cerebral malaria (ECM) in C57BL/6 mice. Treatment with soluble T. gondii antigens (STAg) reduced parasite sequestration and T cell infiltration in the brains of P. berghei-infected mice. Administration of STAg also preserved blood-brain barrier function, reduced ECM symptoms, and significantly decreased mortality. STAg treatment 24 h post-P. berghei infection led to a rapid increase in serum levels of interleukin 12 (IL-12) and gamma interferon (IFN-γ). By 5 days after P. berghei infection, STAg-treated mice had reduced IFN-γ levels compared to those of mock-treated mice, suggesting that reductions in IFN-γ at the time of ECM onset protected against lethality. Using IL-10- and IL-12βR-deficient mice, we found that STAg-induced protection from ECM is IL-10 independent but IL-12 dependent. Treatment of P. berghei-infected mice with recombinant IL-12 significantly decreased parasitemia and mortality. These data suggest that IL-12, either induced by STAg or injected as a recombinant protein, mediates protection from ECM-associated pathology potentially through early induction of IFN-γ and reduction in parasitemia. These results highlight the importance of early IL-12 induction in protection against ECM.
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94
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Effect of mature blood-stage Plasmodium parasite sequestration on pathogen biomass in mathematical and in vivo models of malaria. Infect Immun 2013; 82:212-20. [PMID: 24144725 DOI: 10.1128/iai.00705-13] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Parasite biomass and microvasculature obstruction are strongly associated with disease severity and death in Plasmodium falciparum-infected humans. This is related to sequestration of mature, blood-stage parasites (schizonts) in peripheral tissue. The prevailing view is that schizont sequestration leads to an increase in pathogen biomass, yet direct experimental data to support this are lacking. Here, we first studied parasite population dynamics in inbred wild-type (WT) mice infected with the rodent species of malaria, Plasmodium berghei ANKA. As is commonly reported, these mice became moribund due to large numbers of parasites in multiple tissues. We then studied infection dynamics in a genetically targeted line of mice, which displayed minimal tissue accumulation of parasites. We constructed a mathematical model of parasite biomass dynamics, incorporating schizont-specific host clearance, both with and without schizont sequestration. Combined use of mathematical and in vivo modeling indicated, first, that the slowing of parasite growth in the genetically targeted mice can be attributed to specific clearance of schizonts from the circulation and, second, that persistent parasite growth in WT mice can be explained solely as a result of schizont sequestration. Our work provides evidence that schizont sequestration could be a major biological process driving rapid, early increases in parasite biomass during blood-stage Plasmodium infection.
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95
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Frevert U, Nacer A, Cabrera M, Movila A, Leberl M. Imaging Plasmodium immunobiology in the liver, brain, and lung. Parasitol Int 2013; 63:171-86. [PMID: 24076429 DOI: 10.1016/j.parint.2013.09.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 08/28/2013] [Accepted: 09/18/2013] [Indexed: 01/10/2023]
Abstract
Plasmodium falciparum malaria is responsible for the deaths of over half a million African children annually. Until a decade ago, dynamic analysis of the malaria parasite was limited to in vitro systems with the typical limitations associated with 2D monocultures or entirely artificial surfaces. Due to extremely low parasite densities, the liver was considered a black box in terms of Plasmodium sporozoite invasion, liver stage development, and merozoite release into the blood. Further, nothing was known about the behavior of blood stage parasites in organs such as the brain where clinical signs manifest and the ensuing immune response of the host that may ultimately result in a fatal outcome. The advent of fluorescent parasites, advances in imaging technology, and availability of an ever-increasing number of cellular and molecular probes have helped illuminate many steps along the pathogenetic cascade of this deadly tropical parasite.
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Affiliation(s)
- Ute Frevert
- Division of Medical Parasitology, Department of Microbiology, New York University School of Medicine, 341 E 25 Street, New York, NY 10010, USA.
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96
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Waknine-Grinberg JH, Even-Chen S, Avichzer J, Turjeman K, Bentura-Marciano A, Haynes RK, Weiss L, Allon N, Ovadia H, Golenser J, Barenholz Y. Glucocorticosteroids in nano-sterically stabilized liposomes are efficacious for elimination of the acute symptoms of experimental cerebral malaria. PLoS One 2013; 8:e72722. [PMID: 23991146 PMCID: PMC3753236 DOI: 10.1371/journal.pone.0072722] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 07/12/2013] [Indexed: 01/07/2023] Open
Abstract
Cerebral malaria is the most severe complication of Plasmodium falciparum infection, and a leading cause of death in children under the age of five in malaria-endemic areas. We report high therapeutic efficacy of a novel formulation of liposome-encapsulated water-soluble glucocorticoid prodrugs, and in particular β-methasone hemisuccinate (BMS), for treatment of experimental cerebral malaria (ECM), using the murine P. berghei ANKA model. BMS is a novel derivative of the potent steroid β-methasone, and was specially synthesized to enable remote loading into nano-sterically stabilized liposomes (nSSL), to form nSSL-BMS. The novel nano-drug, composed of nSSL remote loaded with BMS, dramatically improves drug efficacy and abolishes the high toxicity seen upon administration of free BMS. nSSL-BMS reduces ECM rates in a dose-dependent manner and creates a survival time-window, enabling administration of an antiplasmodial drug, such as artemisone. Administration of artemisone after treatment with the nSSL-BMS results in complete cure. Treatment with BMS leads to lower levels of cerebral inflammation, demonstrated by changes in cytokines, chemokines, and cell markers, as well as diminished hemorrhage and edema, correlating with reduced clinical score. Administration of the liposomal formulation results in accumulation of BMS in the brains of sick mice but not of healthy mice. This steroidal nano-drug effectively eliminates the adverse effects of the cerebral syndrome even when the treatment is started at late stages of disease, in which disruption of the blood-brain barrier has occurred and mice show clear signs of neurological impairment. Overall, sequential treatment with nSSL-BMS and artemisone may be an efficacious and well-tolerated therapy for prevention of CM, elimination of parasites, and prevention of long-term cognitive damage.
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Affiliation(s)
- Judith H. Waknine-Grinberg
- Laboratory of Membrane and Liposome Research, Department of Biochemistry, Institute for Medical Research – Israel-Canada (IMRIC), The Hebrew University - Hadassah Medical School, Jerusalem, Israel
- Department of Microbiology and Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University - Hadassah Medical School, Jerusalem, Israel
| | - Simcha Even-Chen
- Laboratory of Membrane and Liposome Research, Department of Biochemistry, Institute for Medical Research – Israel-Canada (IMRIC), The Hebrew University - Hadassah Medical School, Jerusalem, Israel
| | - Jasmine Avichzer
- Agnes Ginges Center for Human Neurogenetics, Department of Neurology, Hadassah University Hospital, Jerusalem, Israel
| | - Keren Turjeman
- Laboratory of Membrane and Liposome Research, Department of Biochemistry, Institute for Medical Research – Israel-Canada (IMRIC), The Hebrew University - Hadassah Medical School, Jerusalem, Israel
| | - Annael Bentura-Marciano
- Department of Microbiology and Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University - Hadassah Medical School, Jerusalem, Israel
| | - Richard K. Haynes
- Department of Chemistry, Institute of Molecular Technology for Drug Discovery and Synthesis, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Lola Weiss
- Department of Bone Marrow Transplantation and Cancer Immunotherapy, Hadassah University Hospital, Jerusalem, Israel
| | - Nahum Allon
- Laboratory of Membrane and Liposome Research, Department of Biochemistry, Institute for Medical Research – Israel-Canada (IMRIC), The Hebrew University - Hadassah Medical School, Jerusalem, Israel
| | - Haim Ovadia
- Agnes Ginges Center for Human Neurogenetics, Department of Neurology, Hadassah University Hospital, Jerusalem, Israel
| | - Jacob Golenser
- Department of Microbiology and Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University - Hadassah Medical School, Jerusalem, Israel
| | - Yechezkel Barenholz
- Laboratory of Membrane and Liposome Research, Department of Biochemistry, Institute for Medical Research – Israel-Canada (IMRIC), The Hebrew University - Hadassah Medical School, Jerusalem, Israel
- * E-mail: (YB), (JG)
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97
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Transdermal glyceryl trinitrate as an effective adjunctive treatment with artemether for late-stage experimental cerebral malaria. Antimicrob Agents Chemother 2013; 57:5462-71. [PMID: 23979751 DOI: 10.1128/aac.00488-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Cerebral malaria (CM) is associated with low nitric oxide (NO) bioavailability, cerebrovascular constriction, occlusion, and hypoperfusion. Administration of exogenous NO partially prevents the neurological syndrome and associated vascular pathology in an experimental CM (ECM) mouse model. In this study, we evaluated the effects of transdermal glyceryl trinitrate in preventing ECM and, in combination with artemether, rescuing late-stage ECM mice from mortality. The glyceryl trinitrate and/or artemether effect on survival and clinical recovery was evaluated in C57BL/6 mice infected with P. berghei ANKA. NO synthase (NOS) expression in mouse brain was determined by Western blots. Mean arterial pressure (MAP) and pial arteriolar diameter were monitored using a tail-cuff blood pressure system and a cranial window preparation, respectively. Preventative administration of glyceryl trinitrate at 0.025 mg/h decreased ECM mortality from 67 to 11% and downregulated inducible NOS expression in the brain. When administered as adjunctive rescue therapy with artemether, glyceryl trinitrate increased survival from 47 to 79%. The adjunctive therapy caused a sustained reversal of pial arteriolar vasoconstriction in ECM mice, an effect not observed with artemether alone. Glyceryl trinitrate induced a 13% decrease in MAP in uninfected mice but did not further affect MAP in hypotensive ECM mice. Glyceryl trinitrate, when combined with artemether, was an effective adjunctive rescue treatment for ECM. This treatment ameliorated pial arteriolar vasospasm and did not significantly affect MAP. These results indicate that transdermal glyceryl trinitrate has potential to be considered as a candidate for adjunctive therapy for CM.
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98
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Maglinao M, Klopfleisch R, Seeberger PH, Lepenies B. The C-type lectin receptor DCIR is crucial for the development of experimental cerebral malaria. THE JOURNAL OF IMMUNOLOGY 2013; 191:2551-9. [PMID: 23918990 DOI: 10.4049/jimmunol.1203451] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cerebral malaria (CM) is the most severe complication of malaria. The murine Plasmodium berghei ANKA (PbA) infection model has helped to identify crucial players in the pathogenesis of CM. However, the role of pattern recognition receptors in innate immunity to CM induction is still poorly understood. C-type lectin receptors (CLRs) represent a family of pattern recognition receptors that recognize carbohydrate structures on pathogens and self-Ags often in a Ca(2+)-dependent manner. In this study, we investigated the role of the CLR dendritic cell immunoreceptor (DCIR) in the genesis of CM. Using the murine PbA infection, we show in this article that DCIR is essential for the development of CM. Although PbA infection led to 80% CM in wild-type C57BL/6 mice, DCIR-deficient mice were highly protected with only 15% CM development. In accordance with the reduced CM incidence in DCIR(-/-) mice, CD8(+) T cell sequestration was markedly reduced in brains of PbA-infected DCIR(-/-) mice, which was accompanied by reduced brain inflammation. Reduced T cell sequestration in the brain was caused by decreased TNF-α levels in sera, as well as a modulated activation of CD4(+) and CD8(+) T cells in spleen of PbA-infected DCIR(-/-) mice. This study indicates that DCIR is critically involved in CM induction, thus highlighting the importance of this CLR in innate immunity during malaria infection.
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Affiliation(s)
- Maha Maglinao
- Department of Biomolecular Systems, Max Planck Institute of Colloids and Interfaces, 14476 Potsdam, Germany
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99
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Jain K, Sood S, Gowthamarajan K. Modulation of cerebral malaria by curcumin as an adjunctive therapy. Braz J Infect Dis 2013; 17:579-91. [PMID: 23906771 PMCID: PMC9425129 DOI: 10.1016/j.bjid.2013.03.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Revised: 03/20/2013] [Accepted: 03/21/2013] [Indexed: 12/31/2022] Open
Abstract
Cerebral malaria is the most severe and rapidly fatal neurological complication of Plasmodium falciparum infection and responsible for more than two million deaths annually. The current therapy is inadequate in terms of reducing mortality or post-treatment symptoms such as neurological and cognitive deficits. The pathophysiology of cerebral malaria is quite complex and offers a variety of targets which remain to be exploited for better therapeutic outcome. The present review discusses on the pathophysiology of cerebral malaria with particular emphasis on scope and promises of curcumin as an adjunctive therapy to improve survival and overcome neurological deficits.
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Affiliation(s)
- Kunal Jain
- Department of Pharmaceutics, J.S.S. College of Pharmacy, Udhagamandalam, Tamilnadu 643001, India.
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100
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Khaw LT, Ball HJ, Golenser J, Combes V, Grau GE, Wheway J, Mitchell AJ, Hunt NH. Endothelial cells potentiate interferon-γ production in a novel tripartite culture model of human cerebral malaria. PLoS One 2013; 8:e69521. [PMID: 23874969 PMCID: PMC3709908 DOI: 10.1371/journal.pone.0069521] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 06/12/2013] [Indexed: 01/13/2023] Open
Abstract
We have established a novel in vitro co-culture system of human brain endothelial cells (HBEC), Plasmodium falciparum parasitised red blood cells (iRBC) and peripheral blood mononuclear cells (PBMC), in order to simulate the chief pathophysiological lesion in cerebral malaria (CM). This approach has revealed a previously unsuspected pro-inflammatory role of the endothelial cell through potentiating the production of interferon (IFN)-γ by PBMC and concurrent reduction of interleukin (IL)-10. The IFN-γ increased the expression of CXCL10 and intercellular adhesion molecule (ICAM)-1, both of which have been shown to be crucial in the pathogenesis of CM. There was a shift in the ratio of IL-10:IFN-γ protein from >1 to <1 in the presence of HBEC, associated with the pro-inflammatory process in this model. For this to occur, a direct contact between PBMC and HBEC, but not PBMC and iRBC, was necessary. These results support HBEC playing an active role in the pathogenesis of CM. Thus, if these findings reflect the pathogenesis of CM, inhibition of HBEC and PBMC interactions might reduce the occurrence, or improve the prognosis, of the condition.
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Affiliation(s)
- Loke Tim Khaw
- School of Medical Sciences and Bosch Institute, University of Sydney, Sydney, Australia
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Helen J. Ball
- School of Medical Sciences and Bosch Institute, University of Sydney, Sydney, Australia
| | - Jacob Golenser
- Department of Microbiology and Molecular Genetics, The Kuvin Center for the Research of Tropical and Infectious Diseases, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Valery Combes
- School of Medical Sciences and Bosch Institute, University of Sydney, Sydney, Australia
| | - Georges E. Grau
- School of Medical Sciences and Bosch Institute, University of Sydney, Sydney, Australia
| | - Julie Wheway
- School of Medical Sciences and Bosch Institute, University of Sydney, Sydney, Australia
| | - Andrew J. Mitchell
- School of Medical Sciences and Bosch Institute, University of Sydney, Sydney, Australia
| | - Nicholas H. Hunt
- School of Medical Sciences and Bosch Institute, University of Sydney, Sydney, Australia
- * E-mail:
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