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Richards CM, McRae SA, Ranger AL, Klegeris A. Extracellular histones as damage-associated molecular patterns in neuroinflammatory responses. Rev Neurosci 2023; 34:533-558. [PMID: 36368030 DOI: 10.1515/revneuro-2022-0091] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 10/18/2022] [Indexed: 07/20/2023]
Abstract
The four core histones H2A, H2B, H3, H4, and the linker histone H1 primarily bind DNA and regulate gene expression within the nucleus. Evidence collected mainly from the peripheral tissues illustrates that histones can be released into the extracellular space by activated or damaged cells. In this article, we first summarize the innate immune-modulatory properties of extracellular histones and histone-containing complexes, such as nucleosomes, and neutrophil extracellular traps (NETs), described in peripheral tissues. There, histones act as damage-associated molecular patterns (DAMPs), which are a class of endogenous molecules that trigger immune responses by interacting directly with the cellular membranes and activating pattern recognition receptors (PRRs), such as toll-like receptors (TLR) 2, 4, 9 and the receptor for advanced glycation end-products (RAGE). We then focus on the available evidence implicating extracellular histones as DAMPs of the central nervous system (CNS). It is becoming evident that histones are present in the brain parenchyma after crossing the blood-brain barrier (BBB) or being released by several types of brain cells, including neurons, microglia, and astrocytes. However, studies on the DAMP-like effects of histones on CNS cells are limited. For example, TLR4 is the only known molecular target of CNS extracellular histones and their interactions with other PRRs expressed by brain cells have not been observed. Nevertheless, extracellular histones are implicated in the pathogenesis of a variety of neurological disorders characterized by sterile neuroinflammation; therefore, detailed studies on the role these proteins and their complexes play in these pathologies could identify novel therapeutic targets.
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Affiliation(s)
- Christy M Richards
- Department of Biology, University of British Columbia Okanagan Campus, Kelowna V1V 1V7, BC, Canada
| | - Seamus A McRae
- Department of Biology, University of British Columbia Okanagan Campus, Kelowna V1V 1V7, BC, Canada
| | - Athena L Ranger
- Department of Biology, University of British Columbia Okanagan Campus, Kelowna V1V 1V7, BC, Canada
| | - Andis Klegeris
- Department of Biology, University of British Columbia Okanagan Campus, Kelowna V1V 1V7, BC, Canada
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2
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Lannes-Vieira J, Vilar-Pereira G, Barrios LC, Silva AA. Anxiety, depression, and memory loss in Chagas disease: a puzzle far beyond neuroinflammation to be unpicked and solved. Mem Inst Oswaldo Cruz 2023; 118:e220287. [PMID: 37018799 PMCID: PMC10072003 DOI: 10.1590/0074-02760220287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/16/2023] [Indexed: 04/07/2023] Open
Abstract
Mental disorders such as anxiety, depression, and memory loss have been described in patients with chronic Chagas disease (CD), a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. Social, psychological, and biological stressors may take part in these processes. There is a consensus on the recognition of an acute nervous form of CD. In chronic CD patients, a neurological form is associated with immunosuppression and neurobehavioural changes as sequelae of stroke. The chronic nervous form of CD has been refuted, based on the absence of histopathological lesions and neuroinflammation; however, computed tomography shows brain atrophy. Overall, in preclinical models of chronic T. cruzi infection in the absence of neuroinflammation, behavioural disorders such as anxiety and depression, and memory loss are related to brain atrophy, parasite persistence, oxidative stress, and cytokine production in the central nervous system. Interferon-gamma (IFNγ)-bearing microglial cells are colocalised with astrocytes carrying T. cruzi amastigote forms. In vitro studies suggest that IFNγ fuels astrocyte infection by T. cruzi and implicate IFNγ-stimulated infected astrocytes as sources of TNF and nitric oxide, which may also contribute to parasite persistence in the brain tissue and promote behavioural and neurocognitive changes. Preclinical trials in chronically infected mice targeting the TNF pathway or the parasite opened paths for therapeutic approaches with a beneficial impact on depression and memory loss. Despite the path taken, replicating aspects of the chronic CD and testing therapeutic schemes in preclinical models, these findings may get lost in translation as the chronic nervous form of CD does not fulfil biomedical model requirements, as the presence of neuroinflammation, to be recognised. It is hoped that brain atrophy and behavioural and neurocognitive changes are sufficient traits to bring the attention of researchers to study the biological and molecular basis of the central nervous system commitment in chronic CD.
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Affiliation(s)
- Joseli Lannes-Vieira
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Biologia das Interações, Rio de Janeiro, RJ, Brasil
| | - Glaucia Vilar-Pereira
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Biologia das Interações, Rio de Janeiro, RJ, Brasil
| | - Leda Castaño Barrios
- Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Biologia das Interações, Rio de Janeiro, RJ, Brasil
| | - Andrea Alice Silva
- Universidade Federal Fluminense, Faculdade de Medicina, Departamento de Patologia, Laboratório Multidisciplinar de Apoio à Pesquisa em Nefrologia e Ciências Médicas, Niterói, RJ, Brasil
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3
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Wincott CJ, Sritharan G, Benns HJ, May D, Gilabert-Carbajo C, Bunyan M, Fairweather AR, Alves E, Andrew I, Game L, Frickel EM, Tiengwe C, Ewald SE, Child MA. Cellular barcoding of protozoan pathogens reveals the within-host population dynamics of Toxoplasma gondii host colonization. CELL REPORTS METHODS 2022; 2:100274. [PMID: 36046624 PMCID: PMC9421581 DOI: 10.1016/j.crmeth.2022.100274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/20/2022] [Accepted: 07/22/2022] [Indexed: 02/09/2023]
Abstract
Cellular barcoding techniques are powerful tools to understand microbial pathogenesis. However, barcoding strategies have not been broadly applied to protozoan parasites, which have unique genomic structures and virulence strategies compared with viral and bacterial pathogens. Here, we present a CRISPR-based method to barcode protozoa, which we successfully apply to Toxoplasma gondii and Trypanosoma brucei. Using libraries of barcoded T. gondii, we evaluate shifts in the population structure from acute to chronic infection of mice. Contrary to expectation, most barcodes were present in the brain one month post-intraperitoneal infection in both inbred CBA/J and outbred Swiss mice. Although parasite cyst number and barcode diversity declined over time, barcodes representing a minor fraction of the inoculum could become a dominant population in the brain by three months post-infection. These data establish a cellular barcoding approach for protozoa and evidence that the blood-brain barrier is not a major bottleneck to colonization by T. gondii.
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Affiliation(s)
- Ceire J. Wincott
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Gayathri Sritharan
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
- Department of Biological Sciences, Birkbeck, University of London, Mallet Street, Bloomsbury, London WC1E 7HX, UK
| | - Henry J. Benns
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
- Department of Chemistry, Imperial College London, White City Campus, London W12 0BZ, UK
| | - Dana May
- Department of Microbiology, Immunology and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Carla Gilabert-Carbajo
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Monique Bunyan
- Host-Toxoplasma Interaction Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1BF, UK
| | - Aisling R. Fairweather
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Eduardo Alves
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Ivan Andrew
- UKRI London Institute of Medical Sciences Genomics Laboratory, Shepherd’s Bush, London W12 0NN, UK
| | - Laurence Game
- UKRI London Institute of Medical Sciences Genomics Laboratory, Shepherd’s Bush, London W12 0NN, UK
| | - Eva-Maria Frickel
- Host-Toxoplasma Interaction Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1BF, UK
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston B15 2TT, UK
| | - Calvin Tiengwe
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Sarah E. Ewald
- Department of Microbiology, Immunology and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Matthew A. Child
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
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4
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Elsheikha HM, Marra CM, Zhu XQ. Epidemiology, Pathophysiology, Diagnosis, and Management of Cerebral Toxoplasmosis. Clin Microbiol Rev 2021; 34:e00115-19. [PMID: 33239310 PMCID: PMC7690944 DOI: 10.1128/cmr.00115-19] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Toxoplasma gondii is known to infect a considerable number of mammalian and avian species and a substantial proportion of the world's human population. The parasite has an impressive ability to disseminate within the host's body and employs various tactics to overcome the highly regulatory blood-brain barrier and reside in the brain. In healthy individuals, T. gondii infection is largely tolerated without any obvious ill effects. However, primary infection in immunosuppressed patients can result in acute cerebral or systemic disease, and reactivation of latent tissue cysts can lead to a deadly outcome. It is imperative that treatment of life-threatening toxoplasmic encephalitis is timely and effective. Several therapeutic and prophylactic regimens have been used in clinical practice. Current approaches can control infection caused by the invasive and highly proliferative tachyzoites but cannot eliminate the dormant tissue cysts. Adverse events and other limitations are associated with the standard pyrimethamine-based therapy, and effective vaccines are unavailable. In this review, the epidemiology, economic impact, pathophysiology, diagnosis, and management of cerebral toxoplasmosis are discussed, and critical areas for future research are highlighted.
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Affiliation(s)
- Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Loughborough, United Kingdom
| | - Christina M Marra
- Departments of Neurology and Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, People's Republic of China
- College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province, People's Republic of China
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5
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Nie LB, Liang QL, Elsheikha HM, Du R, Zhu XQ, Li FC. Global profiling of lysine 2-hydroxyisobutyrylome in Toxoplasma gondii using affinity purification mass spectrometry. Parasitol Res 2020; 119:4061-4071. [PMID: 33057814 DOI: 10.1007/s00436-020-06923-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/06/2020] [Indexed: 11/28/2022]
Abstract
Lysine 2-hydroxyisobutyrylation (Khib) is a recently discovered and evolutionarily conserved form of protein post-translational modification (PTM) found in mammalian and yeast cells. Previous studies have shown that Khib plays roles in the activity of gene transcription and Khib-containing proteins are closely related to the cellular metabolism. In this study, a global Khib-containing analysis using the latest databases (ToxoDB 46, 8322 sequences, downloaded on April 16, 2020) and sensitive immune-affinity enrichment coupled with liquid chromatography-tandem mass spectrometry was performed. A total of 1078 Khib modification sites across 400 Khib-containing proteins were identified in tachyzoites of Toxoplasma gondii RH strain. Bioinformatics and functional enrichment analysis showed that Khib-modified proteins were associated with various biological processes, such as ribosome, glycolysis/gluconeogenesis, and central carbon metabolism. Interestingly, many proteins of the secretory organelles (e.g., microneme, rhoptry, and dense granule) that play roles in the infection cycle of T. gondii were found to be Khib-modified, suggesting the involvement of Khib in key biological process during T. gondii infection. We also found that histone proteins, key enzymes related to cellular metabolism, and several glideosome components had Khib sites. These results expanded our understanding of the roles of Khib in T. gondii and should promote further investigations of how Khib regulates gene expression and key biological functions in T. gondii.
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Affiliation(s)
- Lan-Bi Nie
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, Jilin Province, People's Republic of China.,State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, Gansu Province, People's Republic of China
| | - Qin-Li Liang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, Gansu Province, People's Republic of China
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Rui Du
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, 130118, Jilin Province, People's Republic of China
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, Gansu Province, People's Republic of China. .,College of Veterinary Medicine, Shanxi Agricultural University, Taigu, 030801, Shanxi Province, People's Republic of China.
| | - Fa-Cai Li
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, Gansu Province, People's Republic of China.,College of Veterinary Medicine, Southwest University, Chongqing, 400715, People's Republic of China
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6
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Structural, Functional, and Metabolic Alterations in Human Cerebrovascular Endothelial Cells during Toxoplasma gondii Infection and Amelioration by Verapamil In Vitro. Microorganisms 2020; 8:microorganisms8091386. [PMID: 32927732 PMCID: PMC7564162 DOI: 10.3390/microorganisms8091386] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/01/2020] [Accepted: 09/08/2020] [Indexed: 12/12/2022] Open
Abstract
Toxoplasma gondii (T. gondii), the causative agent of toxoplasmosis, is a frequent cause of brain infection. Despite its known ability to invade the brain, there is still a dire need to better understand the mechanisms by which this parasite interacts with and crosses the blood–brain barrier (BBB). The present study revealed structural and functional changes associated with infection and replication of T. gondii within human brain microvascular endothelial cells (BMECs) in vitro. T. gondii proliferated within the BMECs and disrupted the integrity of the cerebrovascular barrier through diminishing the cellular viability, disruption of the intercellular junctions and increasing permeability of the BMEC monolayer, as well as altering lipid homeostasis. Proton nuclear magnetic resonance (1H NMR)-based metabolomics combined with multivariate data analysis revealed profiles that can be attributed to infection and variations in the amounts of certain metabolites (e.g., amino acids, fatty acids) in the extracts of infected compared to control cells. Notably, treatment with the Ca2+ channel blocker verapamil rescued BMEC barrier integrity and restricted intracellular replication of the tachyzoites regardless of the time of treatment application (i.e., prior to infection, early- and late-infection). This study provides new insights into the structural and functional changes that accompany T. gondii infection of the BMECs, and sheds light upon the ability of verapamil to inhibit the parasite proliferation and to ameliorate the adverse effects caused by T. gondii infection.
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7
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Harun MSR, Marsh V, Elsaied NA, Webb KF, Elsheikha HM. Effects of Toxoplasma gondii infection on the function and integrity of human cerebrovascular endothelial cells and the influence of verapamil treatment in vitro. Brain Res 2020; 1746:147002. [PMID: 32592740 DOI: 10.1016/j.brainres.2020.147002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 06/07/2020] [Accepted: 06/20/2020] [Indexed: 12/16/2022]
Abstract
Toxoplasma gondii can cause parasitic encephalitis, a life-threatening infection that predominately occurs in immunocompromised individuals. T. gondii has the ability to invade the brain, but the mechanisms by which this parasite crosses the blood-brain-barrier (BBB) remain incompletely understood. The present study reports the changes associated with infection and replication of T. gondii within human brain microvascular endothelial cells (BMECs) in vitro. Our results indicated that exposure to T. gondii had an adverse impact on the function and integrity of the BMECs - through induction of cell cycle arrest, disruption of the BMEC barrier integrity, reduction of cellular viability and vitality, depolarization of the mitochondrial membrane potential, increase of the DNA fragmentation, and alteration of the expression of immune response and tight junction genes. The calcium channel/P-glycoprotein transporter inhibitor verapamil was effective in inhibiting T. gondii crossing the BMECs in a dose-dependent manner. The present study showed that T. gondii can compromise several functions of BMECs and demonstrated the ability of verapamil to inhibit T. gondii crossing of the BMECs in vitro.
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Affiliation(s)
- M S R Harun
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, UK; Infectomics Cluster, Advanced Medical & Dental Institute, Universiti Sains Malaysia, Bertam, 13200 Kepala Batas, Pulau Pinang, Malaysia
| | - Victoria Marsh
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, UK
| | - Nashwa A Elsaied
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, UK
| | - Kevin F Webb
- Department of Electrical & Electronic Engineering, University of Nottingham, Nottingham NG7 2RD, UK
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, UK.
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8
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Harun MSR, Taylor M, Zhu XQ, Elsheikha HM. Transcriptome Profiling of Toxoplasma gondii-Infected Human Cerebromicrovascular Endothelial Cell Response to Treatment with Monensin. Microorganisms 2020; 8:microorganisms8060842. [PMID: 32512820 PMCID: PMC7356316 DOI: 10.3390/microorganisms8060842] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 05/26/2020] [Accepted: 06/01/2020] [Indexed: 01/21/2023] Open
Abstract
Central to the progression of cerebral toxoplasmosis is the interaction of Toxoplasma gondii with the blood-brain barrier (BBB) endothelial cells. In the present work, we tested the hypothesis that inhibition of Wnt pathway signalling by the monovalent ionophore monensin reduces the growth of T. gondii infecting human brain microvascular endothelial cells (hBMECs) or microglial cells. The anti-parasitic effect of monensin (a Wnt signalling inhibitor) on the in vitro growth of T. gondii tachyzoites was investigated using two methods (Sulforhodamine B staining and microscopic parasite counting). The monensin inhibited T. gondii growth (50% inhibitory concentration [IC50] = 0.61 μM) with a selective index = 8.48 when tested against hBMECs (50% cytotoxic concentration [CC50] = 5.17 μM). However, IC50 of monensin was 4.13 μM with a SI = 13.82 when tested against microglia cells (CC50 = 57.08 μM), suggesting less sensitivity of microglia cells to monensin treatment. The effect of T. gondii on the integrity of the BBB was assessed by the transendothelial electrical resistance (TEER) assay using an in vitro human BBB model. The results showed that T. gondii infection significantly decreased hBMECs' TEER resistance, which was rescued when cells were treated with 0.1 µM monensin, probably due to the anti-parasitic activity of monensin. We also investigated the host-targeted effects of 0.1 µM monensin on global gene expression in hBMECs with or without T. gondii infection. Treatment of hBMECs with monensin did not significantly influence the expression of genes involved in the Wnt signalling pathway, suggesting that although inhibition of the Wnt signalling pathway did not play a significant role in T. gondii infection of hBMECs, monensin was still effective in limiting the growth of T. gondii. On the contrary, monensin treatment downregulated pathways related to steroids, cholesterol and protein biosynthesis and their transport between endoplasmic reticulum and Golgi apparatus, and deregulated pathways related to cell cycle and DNA synthesis and repair mechanisms. These results provide new insight into the host-modulatory effect of monensin during T. gondii infection, which merits further investigation.
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Affiliation(s)
- Mohammad S. R. Harun
- Infectomics Cluster, Advanced Medical & Dental Institute, Universiti Sains Malaysia, Bertam, Kepala Batas, Pulau Pinang 13200, Malaysia;
| | - Mica Taylor
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK;
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China
- Correspondence: (X.-Q.Z.); (H.M.E.); Tel.: +86-(0)931-834-2837 (X.-Q.Z.); +44-(0)115-951-6445 (H.M.E); Fax: +44-(0)115-951-6440 (H.M.E.)
| | - Hany M. Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK;
- Correspondence: (X.-Q.Z.); (H.M.E.); Tel.: +86-(0)931-834-2837 (X.-Q.Z.); +44-(0)115-951-6445 (H.M.E); Fax: +44-(0)115-951-6440 (H.M.E.)
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9
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Acanthamoeba mauritaniensis genotype T4D: An environmental isolate displays pathogenic behavior. Parasitol Int 2019; 74:102002. [PMID: 31669294 DOI: 10.1016/j.parint.2019.102002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/08/2019] [Accepted: 10/21/2019] [Indexed: 12/13/2022]
Abstract
Acanthamoeba spp. are free-living amoebae with a worldwide distribution. These amoebae can cause granulomatous amoebic encephalitis and amoebic keratitis in humans. Proteases are considered virulence factors in pathogenic Acanthamoeba. The objective of this study was to evaluate the behavior of Acanthamoeba mauritaniensis, a nonpathogenic amoeba. We analyzed the cytopathic effect of A. mauritaniensis on RCE1(5 T5) and MDCK cells and compared it to that of Acanthamoeba castellanii. A partial biochemical characterization of proteases was performed in total crude extracts (TCE) and conditioned medium (CM). Finally, we evaluated the effect of proteases on tight junction (TJ) proteins and the transepithelial electrical resistance of MDCK cells. The results showed that this amoeba can induce substantial damage to RCE1(5T5) and MDCK cells. Moreover, the zymograms and Azocoll assays of amoebic TCE and CM revealed different protease activities, with serine proteases being the most active. Furthermore, A. mauritaniensis induced the alteration and degradation of MDCK cell TJ proteins with serine proteases. After genotyping this amoeba, we determined that it is an isolate of Acanthamoeba genotype T4D. From these data, we suggest that A. mauritaniensis genotype T4D behaves similarly to the A. castellanii strain.
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10
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Al-Sandaqchi AT, Brignell C, Collingwood JF, Geraki K, Mirkes EM, Kong K, Castellanos M, May ST, Stevenson CW, Elsheikha HM. Metallome of cerebrovascular endothelial cells infected with Toxoplasma gondii using μ-XRF imaging and inductively coupled plasma mass spectrometry. Metallomics 2019; 10:1401-1414. [PMID: 30183049 DOI: 10.1039/c8mt00136g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this study, we measured the levels of elements in human brain microvascular endothelial cells (ECs) infected with T. gondii. ECs were infected with tachyzoites of the RH strain, and at 6, 24, and 48 hours post infection (hpi), the intracellular concentrations of elements were determined using a synchrotron-microfocus X-ray fluorescence microscopy (μ-XRF) system. This method enabled the quantification of the concentrations of Zn and Ca in infected and uninfected (control) ECs at sub-micron spatial resolution. T. gondii-hosting ECs contained less Zn than uninfected cells only at 48 hpi (p < 0.01). The level of Ca was not significantly different between infected and control cells (p > 0.05). Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis revealed infection-specific metallome profiles characterized by significant increases in the intracellular levels of Zn, Fe, Mn and Cu at 48 hpi (p < 0.01), and significant reductions in the extracellular concentrations of Co, Cu, Mo, V, and Ag at 24 hpi (p < 0.05) compared with control cells. Zn constituted the largest part (74%) of the total metal composition (metallome) of the parasite. Gene expression analysis showed infection-specific upregulation in the expression of five genes, MT1JP, MT1M, MT1E, MT1F, and MT1X, belonging to the metallothionein gene family. These results point to a possible correlation between T. gondii infection and increased expression of MT1 isoforms and altered intracellular levels of elements, especially Zn and Fe. Taken together, a combined μ-XRF and ICP-MS approach is promising for studies of the role of elements in mediating host-parasite interaction.
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Affiliation(s)
- Alaa T Al-Sandaqchi
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Chris Brignell
- School of Mathematical Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | | | - Kalotina Geraki
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Evgeny M Mirkes
- Mathematics Department, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Kenny Kong
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Marcos Castellanos
- Nottingham Arabidopsis Stock Centre, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - Sean T May
- Nottingham Arabidopsis Stock Centre, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - Carl W Stevenson
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire, LE12 5RD, UK.
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11
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Gonçalves DDS, Ferreira MDS, Guimarães AJ. Extracellular Vesicles from the Protozoa Acanthamoeba castellanii: Their Role in Pathogenesis, Environmental Adaptation and Potential Applications. Bioengineering (Basel) 2019; 6:bioengineering6010013. [PMID: 30717103 PMCID: PMC6466093 DOI: 10.3390/bioengineering6010013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/22/2019] [Accepted: 01/26/2019] [Indexed: 12/11/2022] Open
Abstract
Extracellular vesicles (EVs) are membranous compartments of distinct cellular origin and biogenesis, displaying different sizes and include exosomes, microvesicles, and apoptotic bodies. The EVs have been described in almost every living organism, from simple unicellular to higher evolutionary scale multicellular organisms, such as mammals. Several functions have been attributed to these structures, including roles in energy acquisition, cell-to-cell communication, gene expression modulation and pathogenesis. In this review, we described several aspects of the recently characterized EVs of the protozoa Acanthamoeba castellanii, a free-living amoeba (FLA) of emerging epidemiological importance, and compare their features to other parasites' EVs. These A. castellanii EVs are comprised of small microvesicles and exosomes and carry a wide range of molecules involved in many biological processes like cell signaling, carbohydrate metabolism and proteolytic activity, such as kinases, glucanases, and proteases, respectively. Several biomedical applications of these EVs have been proposed lately, including their use in vaccination, biofuel production, and the pharmaceutical industry, such as platforms for drug delivery.
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Affiliation(s)
- Diego de Souza Gonçalves
- Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Rio de Janeiro 24210-130, Brazil.
| | - Marina da Silva Ferreira
- Departamento de Imunologia, Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-970, Brazil.
| | - Allan J Guimarães
- Departamento de Microbiologia e Parasitologia, Instituto Biomédico, Universidade Federal Fluminense, Rio de Janeiro 24210-130, Brazil.
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The Activity of Matrix Metalloproteinases (MMP-2, MMP-9) and Their Tissue Inhibitors (TIMP-1, TIMP-3) in the Cerebral Cortex and Hippocampus in Experimental Acanthamoebiasis. Int J Mol Sci 2018; 19:ijms19124128. [PMID: 30572657 PMCID: PMC6321078 DOI: 10.3390/ijms19124128] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 12/13/2018] [Accepted: 12/14/2018] [Indexed: 12/20/2022] Open
Abstract
The pathological process occurring within the central nervous system (CNS) as a result of the infection by Acanthamoeba spp. is not fully understood. Therefore, the aim of this study was to determine whether Acanthamoeba spp. may affect the levels of matrix metalloproteinases (MMP-2,-9), their tissue inhibitors (TIMP-1,-3) and MMP-9/TIMP-1, MMP-2/TIMP-3 ratios in the cerebral cortex and hippocampus, in relation to the host’s immunological status. Our results showed that Acanthamoeba spp. infection can change the levels of MMP and TIMP in the CNS and may be amenable targets for limiting amoebic encephalitis. The increase in the activity of matrix metalloproteinases during acanthamoebiasis may be primarily the result of inflammation process, probably an increased activity of proteolytic processes, but also (to a lesser extent) a defense mechanism preventing the processes of neurodegeneration.
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Khan K, Khan W. Congenital toxoplasmosis: An overview of the neurological and ocular manifestations. Parasitol Int 2018; 67:715-721. [PMID: 30041005 DOI: 10.1016/j.parint.2018.07.004] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 07/03/2018] [Accepted: 07/11/2018] [Indexed: 12/21/2022]
Abstract
Toxoplasma gondii is an obligate intracellular parasite which is known to infect one-third of the total world population chronically though it is asymptomatic in immunocompetent patients. However, in an immunocompromised patient or an infected fetus, it may cause devastating effects. The parasite may cross the placenta of an infected pregnant woman and probably infect the fetus congenitally. The severity of the infection depends on the gestational age at which the infection has occurred i.e., if it has occurred in the early phase, the rate of transmission is low but the severity is high if the fetus is infected and if it has occurred in the later phase then transmission rate is higher while the severity would be low. Congenital toxoplasmosis may result in non-specific consequences like abortion, intra-uterine growth restriction, jaundice, hepatosplenomegaly or even intra-uterine death. It may also result in neurological or ocular manifestations like intracranial calcifications, hydrocephalus or retinochoroiditis. The diagnosis may be done by serological screening of anti-Toxoplasma antibodies (IgM and IgG) while PCR of the amniotic fluid or the placenta is the confirmatory test. Acute or chronic infections may be differentiated by IgG avidity tests. The treatment regimens include spiramycin to prevent congenital transmission from an infected mother, pyrimethamine, sulfadoxine and folinic acid to treat the infected fetus, CSF shunting for the treatment of hydrocephalus and a combination of pyrimethamine, azithromycin, and corticosteroids for treating ocular toxoplasmosis.
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Affiliation(s)
- Khadija Khan
- Department of Zoology, Section of Parasitology, Aligarh Muslim University, India
| | - Wajihullah Khan
- Department of Zoology, Section of Parasitology, Aligarh Muslim University, India.
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The pathogenesis of microcephaly resulting from congenital infections: why is my baby’s head so small? Eur J Clin Microbiol Infect Dis 2017; 37:209-226. [DOI: 10.1007/s10096-017-3111-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 09/17/2017] [Indexed: 02/07/2023]
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Abstract
SUMMARYProtists are a diverse collection of eukaryotic organisms that account for a significant global infection burden. Often, the immune responses mounted against these parasites cause excessive inflammation and therefore pathology in the host. Elucidating the mechanisms of both protective and harmful immune responses is complex, and often relies of the use of animal models. In any immune response, leucocyte trafficking to the site of infection, or inflammation, is paramount, and this involves the production of chemokines, small chemotactic cytokines of approximately 8–10 kDa in size, which bind to specific chemokine receptors to induce leucocyte movement. Herein, the scientific literature investigating the role of chemokines in the propagation of immune responses against key protist infections will be reviewed, focussing onPlasmodiumspecies,Toxoplasma gondii, Leishmaniaspecies andCryptosporidiumspecies. Interestingly, many studies find that chemokines can in fact, promote parasite survival in the host, by drawing in leucocytes for spread and further replication. Recent developments in drug targeting against chemokine receptors highlights the need for further understanding of the role played by these proteins and their receptors in many different diseases.
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Crossland NA, Ali I, Higbie C, Jackson J, Pirie G, Bauer R. Neurologic amebiasis caused by Balamuthia mandrillaris in an Indian flying fox (Pteropus giganteus). J Vet Diagn Invest 2016; 28:54-8. [PMID: 26762405 DOI: 10.1177/1040638715614346] [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: 11/16/2022] Open
Abstract
A 4-5-month-old intact male Indian flying fox (Pteropus giganteus) was presented to the Baton Rouge Zoo's veterinary hospital with an acute onset of obtundation that was diagnosed with amebic encephalitis. Histologic examination revealed numerous amebic trophozoites within necrotic foci, affecting the occipital cerebrum and surrounding the mesencephalic aqueduct. The etiologic agent, Balamuthia mandrillaris, was determined by multiplex quantitative real-time polymerase chain reaction, immunohistochemistry, and indirect fluorescent antibody test. The current report documented a case of amebic encephalitis within the order Chiroptera.
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Affiliation(s)
- Nicholas A Crossland
- Departments of Pathobiological Sciences (Crossland, Bauer), School of Veterinary Medicine, Louisiana State University, Baton Rouge, LAVeterinary Clinical Sciences (Higbie), School of Veterinary Medicine, Louisiana State University, Baton Rouge, LALouisiana Animal Disease Diagnostic Laboratory, Louisiana State University, Baton Rouge, LA (Bauer)National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA (Ali, Jackson)Baton Rouge Zoo, Baton Rouge, LA (Pirie)
| | - Ibne Ali
- Departments of Pathobiological Sciences (Crossland, Bauer), School of Veterinary Medicine, Louisiana State University, Baton Rouge, LAVeterinary Clinical Sciences (Higbie), School of Veterinary Medicine, Louisiana State University, Baton Rouge, LALouisiana Animal Disease Diagnostic Laboratory, Louisiana State University, Baton Rouge, LA (Bauer)National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA (Ali, Jackson)Baton Rouge Zoo, Baton Rouge, LA (Pirie)
| | - Christine Higbie
- Departments of Pathobiological Sciences (Crossland, Bauer), School of Veterinary Medicine, Louisiana State University, Baton Rouge, LAVeterinary Clinical Sciences (Higbie), School of Veterinary Medicine, Louisiana State University, Baton Rouge, LALouisiana Animal Disease Diagnostic Laboratory, Louisiana State University, Baton Rouge, LA (Bauer)National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA (Ali, Jackson)Baton Rouge Zoo, Baton Rouge, LA (Pirie)
| | - Jonathan Jackson
- Departments of Pathobiological Sciences (Crossland, Bauer), School of Veterinary Medicine, Louisiana State University, Baton Rouge, LAVeterinary Clinical Sciences (Higbie), School of Veterinary Medicine, Louisiana State University, Baton Rouge, LALouisiana Animal Disease Diagnostic Laboratory, Louisiana State University, Baton Rouge, LA (Bauer)National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA (Ali, Jackson)Baton Rouge Zoo, Baton Rouge, LA (Pirie)
| | - Gordon Pirie
- Departments of Pathobiological Sciences (Crossland, Bauer), School of Veterinary Medicine, Louisiana State University, Baton Rouge, LAVeterinary Clinical Sciences (Higbie), School of Veterinary Medicine, Louisiana State University, Baton Rouge, LALouisiana Animal Disease Diagnostic Laboratory, Louisiana State University, Baton Rouge, LA (Bauer)National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA (Ali, Jackson)Baton Rouge Zoo, Baton Rouge, LA (Pirie)
| | - Rudy Bauer
- Departments of Pathobiological Sciences (Crossland, Bauer), School of Veterinary Medicine, Louisiana State University, Baton Rouge, LAVeterinary Clinical Sciences (Higbie), School of Veterinary Medicine, Louisiana State University, Baton Rouge, LALouisiana Animal Disease Diagnostic Laboratory, Louisiana State University, Baton Rouge, LA (Bauer)National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA (Ali, Jackson)Baton Rouge Zoo, Baton Rouge, LA (Pirie)
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Infektionen. NEUROINTENSIV 2015. [PMCID: PMC7175474 DOI: 10.1007/978-3-662-46500-4_32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In diesem Kapitel werden zunächst die für die Neurointensivmedizin wesentlichen bakteriellen Infektionen (Meningitis, spinale und Hirnabszesse, Spondylodiszitis, septisch-embolische Herdenzephalitis) abgehandelt, die trotz gezielt eingesetzter Antibiotika und neurochirurgischer Therapieoptionen noch mit einer erheblichen Morbidität und Mortalität behaftet sind. Besonderheiten wie neurovaskuläre Komplikationen, die Tuberkulose des Nervensystems, Neuroborreliose, Neurosyphilis und opportunistische Infektionen bei Immunsuppressionszuständen finden hierbei besondere Berücksichtigung. Der zweite Teil dieses Kapitels behandelt akute und chronische Virusinfektionen des ZNS sowie in einem gesonderten Abschnitt die HIVInfektion und HIV-assoziierte Krankheitsbilder sowie Parasitosen und Pilzinfektionen, die in Industrieländern seit Einführung der HAART bei HIV zwar eher seltener, aber mit zunehmender Globalisierung auch in unseren Breiten immer noch anzutreffen sind.
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Zhang RL, Zhang JP, Wang QQ. Recombinant Treponema pallidum protein Tp0965 activates endothelial cells and increases the permeability of endothelial cell monolayer. PLoS One 2014; 9:e115134. [PMID: 25514584 PMCID: PMC4267829 DOI: 10.1371/journal.pone.0115134] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 11/19/2014] [Indexed: 02/07/2023] Open
Abstract
The recombinant Treponema pallidum protein Tp0965 (rTp0965), one of the many proteins derived from the genome of T. pallidum subsp. pallidum, shows strong immunogenicity and immunoreactivity. In this study, we investigated the effects of rTp0965 on the endothelial barrier. Treatment of human umbilical vein endothelial cells (HUVECs) with rTp0965 resulted in increased levels of ICAM-1, E-selectin, and MCP-1 mRNA and protein expression. These increases contributed to the adhesion and chemataxis of monocytes (THP-1 cells) to HUVECs preincubated with rTp0965. In addition, rTp0965 induced reorganization of F-actin and decreased expression of claudin-1 in HUVECs. Interestingly, inhibition of the RhoA/ROCK signal pathway protected against rTp0965-induced higher endothelial permeability as well as transendothelial migration of monocytes. These data indicate that Tp0965 protein may play an important role in the immunopathogenesis of syphilis.
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Affiliation(s)
- Rui-Li Zhang
- Department of Dermatology, Wuxi Second Affiliated Hospital of Nanjing Medical University, Wuxi, Jiangsu Province, China
| | - Jing-Ping Zhang
- Institute of Dermatology, Chinese Academy of Medical Sciences & Peking Union Medical College, & National Center for STD Control, China Centers for Diseases Control and Prevention, Nanjing, Jiangsu Province, China
| | - Qian-Qiu Wang
- Institute of Dermatology, Chinese Academy of Medical Sciences & Peking Union Medical College, & National Center for STD Control, China Centers for Diseases Control and Prevention, Nanjing, Jiangsu Province, China
- * E-mail:
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Oz HS. Maternal and congenital toxoplasmosis, currently available and novel therapies in horizon. Front Microbiol 2014; 5:385. [PMID: 25104952 PMCID: PMC4109466 DOI: 10.3389/fmicb.2014.00385] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 07/10/2014] [Indexed: 12/24/2022] Open
Abstract
Over one billion people worldwide are predicted to harbor Toxoplasma infection frequently with unknown lifelong health consequences. Toxoplasmosis is an important cause of foodborne, inflammatory illnesses, as well as congenital abnormalities. Ubiquitous Toxoplasma has a unique tropism for central nervous system with a mind-bugging effect and is transmitted sexually through semen. Currently available therapies are ineffective for persistent chronic disease and congenital toxoplasmosis or have severe side effects which may result in life-threatening complications. There is an urgent need for safe and effective therapies to eliminate or treat this cosmopolitan infectious and inflammatory disease. This investigation discusses pathogenesis of maternal and congenital toxoplasmosis, the currently available therapies in practice, and the experimental therapeutic modalities for promising future trials.
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Affiliation(s)
- Helieh S Oz
- Department of Medicine, University of Kentucky Medical Center Lexington, KY, USA
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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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Crossing the wall: The opening of endothelial cell junctions during infectious diseases. Int J Biochem Cell Biol 2013; 45:1165-73. [DOI: 10.1016/j.biocel.2013.03.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 03/05/2013] [Accepted: 03/15/2013] [Indexed: 12/22/2022]
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Oz HS, Tobin T. Atovaquone ameliorate gastrointestinal toxoplasmosis complications in a pregnancy model. Med Sci Monit 2013; 18:BR337-45. [PMID: 22936182 PMCID: PMC3560658 DOI: 10.12659/msm.883342] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Background Toxoplasma is an important source of foodborne hospitalization with no safe and effective therapy against chronic or congenital Toxopalsmosis. Atovaquone is a drug of choice but not approved for use in congenital Toxoplasmosis. We hypothesized atovaquone to be safe and effective against feto-maternal Toxoplasmosis. Material/Methods Programmed pregnant mice were i.p. infected with 50–2400 Tachyzoites from Type II strain (clone PTG). Dams were treated daily with atovaquone or sham and monitored for pain, and complications. Results Dams developed pain related abdominal hypersensitivity (allodynia) to mechanical stimuli in a Tachyzoites dose dependent manner. Infected dams were anemic and exhibited ascities and severe hepatitis (score 3.6±0.01 on scale 0 – normal to 4 – severe) with influx of inflammatory and plasma cells, multinucleated dysplastic hepatocytes and necrosis. In addition, dams expressed mild to severe pancreatitis with mononuclear cell invasion, loss of islets and necrosis. This was consistent with splenomegaly (X3 Fold), and massive infiltration of epithelioid cells and loss of germinal structure. Colon became significantly shortened in length (p<0.01) with semi-normal content. Pathological manifestation included, shortening of crypts with numerous microabscess formations, infiltration of lymphocytes, and macrophages. The severe clinical complications led to abortion (50%), early birth (25%) or still birth (25%) consistent with the high dose of Tachyzoites inoculation. Atovaquone treatment partially but significantly protected the dams from the severity of hepatitis, splenomegaly, colitis, myocarditis, and pain related responses as well as fetal demise. Conclusions This is a valuable model for therapeutic evaluation of feto-maternal Toxoplasmosis and gastrointestinal complications. Atovaquone protects dams and their fetuses against some infectious/inflammatory aspects of the disease.
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Affiliation(s)
- Helieh S Oz
- Department of Physiology, College of Medicine, University of Kentucky Medical Center, Lexington, KY 40536, USA.
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Abstract
Invasion of the central nervous system (CNS) is a most devastating complication of a parasitic infection. Several physical and immunological barriers provide obstacles to such an invasion. In this broad overview focus is given to the physical barriers to neuroinvasion of parasites provided at the portal of entry of the parasites, i.e., the skin and epithelial cells of the gastrointestinal tract, and between the blood and the brain parenchyma, i.e., the blood-brain barrier (BBB). A description is given on how human pathogenic parasites can reach the CNS via the bloodstream either as free-living or extracellular parasites, by embolization of eggs, or within red or white blood cells when adapted to intracellular life. Molecular mechanisms are discussed by which parasites can interact with or pass across the BBB. The possible targeting of the circumventricular organs by parasites, as well as the parasites' direct entry to the brain from the nasal cavity through the olfactory nerve pathway, is also highlighted. Finally, examples are given which illustrate different mechanisms by which parasites can cause dysfunction or damage in the CNS related to toxic effects of parasite-derived molecules or to immune responses to the infection.
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Sullivan WJ, Jeffers V. Mechanisms of Toxoplasma gondii persistence and latency. FEMS Microbiol Rev 2012; 36:717-33. [PMID: 22091606 PMCID: PMC3319474 DOI: 10.1111/j.1574-6976.2011.00305.x] [Citation(s) in RCA: 169] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 08/22/2011] [Accepted: 08/25/2011] [Indexed: 11/28/2022] Open
Abstract
Toxoplasma gondii is an obligate intracellular protozoan parasite that causes opportunistic disease, particularly in immunocompromised individuals. Central to its transmission and pathogenesis is the ability of the proliferative stage (tachyzoite) to convert into latent tissue cysts (bradyzoites). Encystment allows Toxoplasma to persist in the host and affords the parasite a unique opportunity to spread to new hosts without proceeding through its sexual stage, which is restricted to felids. Bradyzoite tissue cysts can cause reactivated toxoplasmosis if host immunity becomes impaired. A greater understanding of the molecular mechanisms orchestrating bradyzoite development is needed to better manage the disease. Here, we will review key studies that have contributed to our knowledge about this persistent form of the parasite and how to study it, with a focus on how cellular stress can signal for the reprogramming of gene expression needed during bradyzoite development.
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Affiliation(s)
- William J Sullivan
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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Infektionen. NEUROINTENSIV 2012. [PMCID: PMC7123678 DOI: 10.1007/978-3-642-16911-3_32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Trotz Weiterentwicklung moderner Antibiotika in den letzten Jahren sind die Letalitätszahlen der bakteriellen (eitrigen) Meningitis weiterhin hoch; Überlebende haben häufig neurologische Residuen. Die ungünstigen klinischen Verläufe der bakteriellen Meningitis sind meist Folge intrakranieller Komplikationen, wie z. B. eines generalisierten Hirnödems, einer zerebrovaskulären arteriellen oder venösen Beteiligung oder eines Hydrozephalus.
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Grab DJ, Chakravorty SJ, van der Heyde H, Stins MF. How can microbial interactions with the blood-brain barrier modulate astroglial and neuronal function? Cell Microbiol 2011; 13:1470-8. [DOI: 10.1111/j.1462-5822.2011.01661.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Chimelli L. A morphological approach to the diagnosis of protozoal infections of the central nervous system. PATHOLOGY RESEARCH INTERNATIONAL 2011; 2011:290853. [PMID: 21785681 PMCID: PMC3140201 DOI: 10.4061/2011/290853] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Accepted: 05/03/2011] [Indexed: 11/25/2022]
Abstract
Protozoal infections, though endemic to certain regions, can be seen all around the world, because of the increase in travel and migration. In addition, immunosuppression associated with various conditions, particularly with HIV infection, favors the occurrence of more severe manifestations and failure to respond to treatments. The CNS may be the only affected system; when not, it is often the most severely affected. Despite information obtained from clinical, laboratory, and imaging procedures that help to narrow the differential diagnosis of intracranial infections, there are cases that need confirmation with biopsy or autopsy. Predominant presentations are meningoencephalitis (trypanosomiasis), encephalopathy (cerebral malaria), or as single or multiple pseudotumoral enhancing lesions (toxoplasmosis, reactivated Chagas' disease). The immune reconstitution disease, resulting from enhancement of pathogen-specific immune responses after HAART, has altered the typical presentation of toxoplasmosis and microsporidiosis. In this paper, a morphological approach for the diagnosis of protozoal infections affecting the CNS (amoebiasis, cerebral malaria, toxoplasmosis, trypanosomiasis, and microsporidiosis) is presented.
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Affiliation(s)
- Leila Chimelli
- Department of Pathology, University Hospital, Federal University of Rio de Janeiro, 21941-913 Rio de Janeiro, RJ, Brazil
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Siddiqui R, Emes R, Elsheikha H, Khan NA. Area 51: How do Acanthamoeba invade the central nervous system? Trends Parasitol 2011; 27:185-9. [DOI: 10.1016/j.pt.2011.01.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/16/2011] [Accepted: 01/19/2011] [Indexed: 11/30/2022]
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Non-vertebrate models to study parasite invasion of the central nervous system. Trends Parasitol 2010; 27:5-10. [PMID: 20832363 DOI: 10.1016/j.pt.2010.08.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 08/06/2010] [Accepted: 08/10/2010] [Indexed: 11/20/2022]
Abstract
Infections of the central nervous system due to neuroparasites have contributed significantly to morbidity and mortality. In part, this is because of our incomplete understanding of parasite traversal of the blood-brain barrier, a key step in the development of central nervous system infections, and the lack of available drugs that can cross the blood-brain barrier to gain entry into the brain to kill parasites. The novel in vitro, ex vivo, and in vivo models of the blood-brain barrier can offer strategies to elucidate the physical barriers, cellular mechanisms and molecular elements participating from both sides of parasite-host interactions leading to neuropathogenesis. Improving our knowledge of these core processes might elevate the efficiency of therapy of diseases caused by them.
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