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Barnacle JR, Davis AG, Wilkinson RJ. Recent advances in understanding the human host immune response in tuberculous meningitis. Front Immunol 2024; 14:1326651. [PMID: 38264653 PMCID: PMC10803428 DOI: 10.3389/fimmu.2023.1326651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 12/18/2023] [Indexed: 01/25/2024] Open
Abstract
Tuberculous meningitis (TBM), the most severe form of tuberculosis, causes death in approximately 25% cases despite antibiotic therapy, and half of survivors are left with neurological disability. Mortality and morbidity are contributed to by a dysregulated immune response, and adjunctive host-directed therapies are required to modulate this response and improve outcomes. Developing such therapies relies on improved understanding of the host immune response to TBM. The historical challenges in TBM research of limited in vivo and in vitro models have been partially overcome by recent developments in proteomics, transcriptomics, and metabolomics, and the use of these technologies in nested substudies of large clinical trials. We review the current understanding of the human immune response in TBM. We begin with M. tuberculosis entry into the central nervous system (CNS), microglial infection and blood-brain and other CNS barrier dysfunction. We then outline the innate response, including the early cytokine response, role of canonical and non-canonical inflammasomes, eicosanoids and specialised pro-resolving mediators. Next, we review the adaptive response including T cells, microRNAs and B cells, followed by the role of the glutamate-GABA neurotransmitter cycle and the tryptophan pathway. We discuss host genetic immune factors, differences between adults and children, paradoxical reaction, and the impact of HIV-1 co-infection including immune reconstitution inflammatory syndrome. Promising immunomodulatory therapies, research gaps, ongoing challenges and future paths are discussed.
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Affiliation(s)
- James R. Barnacle
- The Francis Crick Institute, London, United Kingdom
- Department of Infectious Disease, Imperial College, London, United Kingdom
- Centre for Infectious Diseases Research in Africa, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
| | - Angharad G. Davis
- The Francis Crick Institute, London, United Kingdom
- Centre for Infectious Diseases Research in Africa, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
| | - Robert J. Wilkinson
- The Francis Crick Institute, London, United Kingdom
- Department of Infectious Disease, Imperial College, London, United Kingdom
- Centre for Infectious Diseases Research in Africa, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
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2
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Ayub M, Jin HK, Bae JS. The blood cerebrospinal fluid barrier orchestrates immunosurveillance, immunoprotection, and immunopathology in the central nervous system. BMB Rep 2021. [PMID: 33298242 PMCID: PMC8093941 DOI: 10.5483/bmbrep.2021.54.4.205] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Once characterized as an immune privileged area, recent scientific advances have demonstrated that the central nervous system (CNS) is both immunologically active and a specialized site. The anatomical and cellular features of the brain barriers, the glia limitans, and other superficial coverings of the CNS endow the brain with specificity for immune cell entry and other macro- and micro-elements to the brain. Cellular trafficking via barriers comprised of tightly junctioned non-fenestrated endothelium or tightly regulated fenestrated epithelium results in different phenotypic and cellular changes in the brain, that is, inflammatory versus regulatory changes. Based on emerging evidence, we described the unique ability of the blood cerebrospinal fluid barrier (BCSFB) to recruit, skew, and suppress immune cells. Additionally, we sum up the current knowledge on both cellular and molecular mechanisms governed by the choroid plexus and the cerebrospinal fluid at the BCSFB for immunosurveillance, immunoprotection, and immunopathology.
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Affiliation(s)
- Maria Ayub
- KNU Alzheimer’s disease Research Institute, Kyungpook National University, Daegu 41566, Korea
- Department of Physiology, School of Medicine, Kyungpook National University, Daegu 41944, Korea
- Department of Biomedical Science, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University, Daegu 41944, Korea
| | - Hee Kyung Jin
- KNU Alzheimer’s disease Research Institute, Kyungpook National University, Daegu 41566, Korea
- Department of Laboratory Animal Medicine, College of Veterinary Medicine, Kyungpook National University, Daegu 41566, Korea
| | - Jae-sung Bae
- KNU Alzheimer’s disease Research Institute, Kyungpook National University, Daegu 41566, Korea
- Department of Physiology, School of Medicine, Kyungpook National University, Daegu 41944, Korea
- Department of Biomedical Science, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University, Daegu 41944, Korea
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3
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Wiatr M, Figueiredo R, Stump-Guthier C, Winter P, Ishikawa H, Adams O, Schwerk C, Schroten H, Rudolph H, Tenenbaum T. Polar Infection of Echovirus-30 Causes Differential Barrier Affection and Gene Regulation at the Blood-Cerebrospinal Fluid Barrier. Int J Mol Sci 2020; 21:E6268. [PMID: 32872518 PMCID: PMC7503638 DOI: 10.3390/ijms21176268] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/26/2020] [Accepted: 08/26/2020] [Indexed: 12/13/2022] Open
Abstract
Echovirus-30 (E-30) is responsible for the extensive global outbreaks of meningitis in children. To gain access to the central nervous system, E-30 first has to cross the epithelial blood-cerebrospinal fluid barrier. Several meningitis causing bacteria preferentially infect human choroid plexus papilloma (HIBCPP) cells in a polar fashion from the basolateral cell side. Here, we investigated the polar infection of HIBCPP cells with E-30. Both apical and basolateral infections caused a significant decrease in the transepithelial electrical resistance of HIBCPP cells. However, to reach the same impact on the barrier properties, the multiplicity of infection of the apical side had to be higher than that of the basolateral infection. Furthermore, the number of infected cells at respective time-points after basolateral infection was significantly higher compared to apical infection. Cytotoxic effects of E-30 on HIBCPP cells during basolateral infection were observed following prolonged infection and appeared more drastically compared to the apical infection. Gene expression profiles determined by massive analysis of cDNA ends revealed distinct regulation of specific genes depending on the side of HIBCPP cells' infection. Altogether, our data highlights the polar effects of E-30 infection in a human in vitro model of the blood-cerebrospinal fluid barrier leading to central nervous system inflammation.
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Affiliation(s)
- Marie Wiatr
- Pediatric Infectious Diseases, University Children’s Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; or (C.S.-G.); (C.S.); (H.S.); or
| | - Ricardo Figueiredo
- GenXpro GmbH, 60438 Frankfurt am Main, Germany; (R.F.); (P.W.)
- Johann Wolfgang Goethe University Frankfurt, 60438 Frankfurt Am Main, Germany
| | - Carolin Stump-Guthier
- Pediatric Infectious Diseases, University Children’s Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; or (C.S.-G.); (C.S.); (H.S.); or
| | - Peter Winter
- GenXpro GmbH, 60438 Frankfurt am Main, Germany; (R.F.); (P.W.)
| | - Hiroshi Ishikawa
- Department of Clinical Regenerative Medicine, Department of Neurosurgery, Faculty of Medicine, University of Tsukuba, Tennodai, Tsukuba, Ibaraki 305-0005, Japan;
| | - Ortwin Adams
- Institute for Virology, Heinrich Heine University, 40225 Düsseldorf, Germany;
| | - Christian Schwerk
- Pediatric Infectious Diseases, University Children’s Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; or (C.S.-G.); (C.S.); (H.S.); or
| | - Horst Schroten
- Pediatric Infectious Diseases, University Children’s Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; or (C.S.-G.); (C.S.); (H.S.); or
| | - Henriette Rudolph
- Pediatric Infectious Diseases, University Children’s Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; or (C.S.-G.); (C.S.); (H.S.); or
| | - Tobias Tenenbaum
- Pediatric Infectious Diseases, University Children’s Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; or (C.S.-G.); (C.S.); (H.S.); or
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4
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Solár P, Zamani A, Kubíčková L, Dubový P, Joukal M. Choroid plexus and the blood-cerebrospinal fluid barrier in disease. Fluids Barriers CNS 2020; 17:35. [PMID: 32375819 PMCID: PMC7201396 DOI: 10.1186/s12987-020-00196-2] [Citation(s) in RCA: 139] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/22/2020] [Indexed: 01/08/2023] Open
Abstract
The choroid plexus (CP) forming the blood-cerebrospinal fluid (B-CSF) barrier is among the least studied structures of the central nervous system (CNS) despite its clinical importance. The CP is an epithelio-endothelial convolute comprising a highly vascularized stroma with fenestrated capillaries and a continuous lining of epithelial cells joined by apical tight junctions (TJs) that are crucial in forming the B-CSF barrier. Integrity of the CP is critical for maintaining brain homeostasis and B-CSF barrier permeability. Recent experimental and clinical research has uncovered the significance of the CP in the pathophysiology of various diseases affecting the CNS. The CP is involved in penetration of various pathogens into the CNS, as well as the development of neurodegenerative (e.g., Alzheimer´s disease) and autoimmune diseases (e.g., multiple sclerosis). Moreover, the CP was shown to be important for restoring brain homeostasis following stroke and trauma. In addition, new diagnostic methods and treatment of CP papilloma and carcinoma have recently been developed. This review describes and summarizes the current state of knowledge with regard to the roles of the CP and B-CSF barrier in the pathophysiology of various types of CNS diseases and sets up the foundation for further avenues of research.
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Affiliation(s)
- Peter Solár
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, CZ-625 00, Brno, Czech Republic
- Department of Neurosurgery, Faculty of Medicine, Masaryk University and St. Anne´s University Hospital Brno, Pekařská 53, CZ-656 91, Brno, Czech Republic
| | - Alemeh Zamani
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, CZ-625 00, Brno, Czech Republic
| | - Lucie Kubíčková
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, CZ-625 00, Brno, Czech Republic
| | - Petr Dubový
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, CZ-625 00, Brno, Czech Republic
| | - Marek Joukal
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, CZ-625 00, Brno, Czech Republic.
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Experimental Porcine Toxoplasma gondii Infection as a Representative Model for Human Toxoplasmosis. Mediators Inflamm 2017; 2017:3260289. [PMID: 28883687 PMCID: PMC5572617 DOI: 10.1155/2017/3260289] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 06/16/2017] [Accepted: 07/05/2017] [Indexed: 12/01/2022] Open
Abstract
Porcine infections are currently not the state-of-the-art model to study human diseases. Nevertheless, the course of human and porcine toxoplasmosis is much more comparable than that of human and murine toxoplasmosis. For example, severity of infection, transplacental transmission, and interferon-gamma-induced antiparasitic effector mechanisms are similar in pigs and humans. In addition, the severe immunosuppression during acute infection described in mice does not occur in the experimentally infected ones. Thus, we hypothesise that porcine Toxoplasma gondii infection data are more representative for human toxoplasmosis. We therefore suggest that the animal model chosen must be critically evaluated for its assignability to human diseases.
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Lipid A-activated inducible nitric oxide synthase expression via nuclear factor-κB in mouse choroid plexus cells. Immunol Lett 2015; 167:57-62. [DOI: 10.1016/j.imlet.2015.07.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 07/08/2015] [Accepted: 07/27/2015] [Indexed: 11/22/2022]
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Zhang Q, Yang Y, Yan S, Liu J, Xu Z, Yu J, Song Y, Zhang A, Jin M. A novel pro-inflammatory protein of Streptococcus suis 2 induces the Toll-like receptor 2-dependent expression of pro-inflammatory cytokines in RAW 264.7 macrophages via activation of ERK1/2 pathway. Front Microbiol 2015; 6:178. [PMID: 25806027 PMCID: PMC4353370 DOI: 10.3389/fmicb.2015.00178] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 02/18/2015] [Indexed: 12/29/2022] Open
Abstract
Streptococcus suis 2 is an important swine pathogen and an emergent zoonotic pathogen. Excessive inflammation caused by S. suis is responsible for the high levels of early mortality observed in septic shock-like syndrome cases. However, the mechanisms through which S. suis 2 (SS2) causes excessive inflammation remain unclear. Thus, this study aimed to identify novel pro-inflammatory mediators that play important roles in the development of therapies against SS2 infection. In this study, the novel pro-inflammatory protein HP0459, which was encoded by the SSUSC84_0459 gene, was discovered. The stimulation of RAW 264.7 macrophages with recombinant HP0459 protein induced the expression of pro-inflammatory cytokines (IL-1β, MCP-1 and TNF-α). Compared with the wild-type (WT) strain, the isogenic knockout of HP0459 in SS2 led to reduced production of pro-inflammatory cytokines in RAW264.7 macrophages and in vivo. The pro-inflammatory activity of HP0459 was significantly reduced by an antibody against Toll-like receptor 2 (TLR2) in RAW264.7 macrophages and was lower in TLR2-deficient (TLR2-/-) macrophages than in WT macrophages. Furthermore, specific inhibitors of the extracellular signal-regulated kinase 1/2 (ERK1/2) pathways significantly decreased the HP0459-induced pro-inflammatory cytokine production, and a western blot assay showed that HP0459 stimulation induced the activation of the ERK1/2 pathway. Taken together, our data indicate that HP0459 is a novel pro-inflammatory mediator of SS2 and induces TLR2-dependent pro-inflammatory activity in RAW264.7 macrophages through the ERK1/2 pathway.
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Affiliation(s)
- Qiang Zhang
- Unit of Animal Infectious Diseases, National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Yujie Yang
- Unit of Animal Infectious Diseases, National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Shuxian Yan
- Unit of Animal Infectious Diseases, National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Jiantao Liu
- Unit of Animal Infectious Diseases, National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Zhongmin Xu
- Unit of Animal Infectious Diseases, National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Junping Yu
- Unit of Animal Infectious Diseases, National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Yajing Song
- Unit of Animal Infectious Diseases, National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Anding Zhang
- Unit of Animal Infectious Diseases, National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China
| | - Meilin Jin
- Unit of Animal Infectious Diseases, National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University Wuhan, China ; Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture Wuhan, China
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Schwerk C, Papandreou T, Schuhmann D, Nickol L, Borkowski J, Steinmann U, Quednau N, Stump C, Weiss C, Berger J, Wolburg H, Claus H, Vogel U, Ishikawa H, Tenenbaum T, Schroten H. Polar invasion and translocation of Neisseria meningitidis and Streptococcus suis in a novel human model of the blood-cerebrospinal fluid barrier. PLoS One 2012; 7:e30069. [PMID: 22253884 PMCID: PMC3256222 DOI: 10.1371/journal.pone.0030069] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 12/09/2011] [Indexed: 11/18/2022] Open
Abstract
Acute bacterial meningitis is a life-threatening disease in humans. Discussed as entry sites for pathogens into the brain are the blood-brain and the blood-cerebrospinal fluid barrier (BCSFB). Although human brain microvascular endothelial cells (HBMEC) constitute a well established human in vitro model for the blood-brain barrier, until now no reliable human system presenting the BCSFB has been developed. Here, we describe for the first time a functional human BCSFB model based on human choroid plexus papilloma cells (HIBCPP), which display typical hallmarks of a BCSFB as the expression of junctional proteins and formation of tight junctions, a high electrical resistance and minimal levels of macromolecular flux when grown on transwell filters. Importantly, when challenged with the zoonotic pathogen Streptococcus suis or the human pathogenic bacterium Neisseria meningitidis the HIBCPP show polar bacterial invasion only from the physiologically relevant basolateral side. Meningococcal invasion is attenuated by the presence of a capsule and translocated N. meningitidis form microcolonies on the apical side of HIBCPP opposite of sites of entry. As a functionally relevant human model of the BCSFB the HIBCPP offer a wide range of options for analysis of disease-related mechanisms at the choroid plexus epithelium, especially involving human pathogens.
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Affiliation(s)
- Christian Schwerk
- Pediatric Infectious Diseases, Department of Pediatrics, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
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Schwerk C, Adam R, Borkowski J, Schneider H, Klenk M, Zink S, Quednau N, Schmidt N, Stump C, Sagar A, Spellerberg B, Tenenbaum T, Koczan D, Klein-Hitpass L, Schroten H. In vitro transcriptome analysis of porcine choroid plexus epithelial cells in response to Streptococcus suis: release of pro-inflammatory cytokines and chemokines. Microbes Infect 2011; 13:953-62. [DOI: 10.1016/j.micinf.2011.05.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 05/19/2011] [Accepted: 05/24/2011] [Indexed: 01/12/2023]
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Marques F, Rodrigues AJ, Sousa JC, Coppola G, Geschwind DH, Sousa N, Correia-Neves M, Palha JA. Lipocalin 2 is a choroid plexus acute-phase protein. J Cereb Blood Flow Metab 2008; 28:450-5. [PMID: 17895910 DOI: 10.1038/sj.jcbfm.9600557] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Lipocalin 2 (LCN2) is able to sequester iron-loaded bacterial siderophores and, therefore, is known to participate in the mammalian innate immune response. Of notice, LCN2 was shown to display bacteriostatic effects both in in vitro and in vivo. To reach the brain, bacteria must cross the blood-brain or the choroid plexus (CP)/cerebrospinal fluid (CSF) barriers. Additionally, as the CP is responsible for the production of most of the CSF, responses of the CP mediate signaling into the brain. We show here that in conditions of peripheral inflammation, LCN2 behaves as an acute phase protein in the CP. As early as 1 h after lipopolysaccharide peripheral administration, Lcn2 mRNA levels are upregulated, returning to basal levels after 72 h. Increased LCN2 protein is observed in choroidal epithelia and in endothelial cells of blood vessels in the brain parenchyma. Higher levels of LCN2 are also present in the CSF. These observations suggest that expression of LCN2 at the CP/CSF barrier might be bacteriostatic in the brain, avoiding bacteria dissemination within the CSF into the brain parenchyma. This study shows that the LCN2 is produced by the CP as a component of the innate immune response that protects the central nervous system from infection.
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Affiliation(s)
- Fernanda Marques
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus Gualtar, Braga, Portugal
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Tenenbaum T, Essmann F, Adam R, Seibt A, Jänicke RU, Novotny GEK, Galla HJ, Schroten H. Cell death, caspase activation, and HMGB1 release of porcine choroid plexus epithelial cells during Streptococcus suis infection in vitro. Brain Res 2006; 1100:1-12. [PMID: 16781680 DOI: 10.1016/j.brainres.2006.05.041] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2006] [Revised: 04/21/2006] [Accepted: 05/03/2006] [Indexed: 11/25/2022]
Abstract
The choroid plexus epithelium constitutes the structural basis of the blood-cerebrospinal fluid barrier. We previously demonstrated that Streptococcus suis (S. suis), a relevant cause of bacterial meningitis in pigs and humans, affects porcine choroid plexus epithelial cell (PCPEC) barrier function and integrity. We now characterized PCPEC cell death and investigated whether apoptosis or necrosis is responsible for the cytotoxicity after infection with different S. suis isolates. We found S. suis strain-dependent histone associated DNA-fragments quantified by ELISA. This response could partially be inhibited by cylcoheximide, cytochalasin D, dexamethasone, herbimycin A, but most effectively by the pan-caspase inhibitor zVAD-fmk. We further detected caspase-3 and -9 activation after infection with all tested S. suis isolates that could also be blocked by zVAD-fmk. However, we found a significantly stronger caspase activity with the protein kinase inhibitor staurosporine. All tested S. suis isolates induced loss of cell viability in PCPEC as shown with the Live/Dead assay, but strain dependent lactate dehydrogenase-release. Both parameters could not be influenced by zVAD-fmk. Immunostaining showed release of high-mobility group box 1 (HMGB1) protein from the nucleus, indicative of necrosis. Transmission electron microscopy showed cell swelling, cytoplasmic vacuolization, loss of membrane integrity, nuclear fermentation but no nuclear condensation, indices for a primarily necrotic cell morphology. Taken together, our findings indicate that S. suis causes cell death in PCPEC by different mechanisms. Although apoptosis may be involved in the process of PCPEC cell death, necrosis seems to be the predominant mechanism. Through inflammation in the choroid plexus during bacterial meningitis, the blood-cerebrospinal fluid barrier function will be compromised.
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Affiliation(s)
- Tobias Tenenbaum
- Pediatric Infectious Diseases, Department for General Pediatrics, University Children's Hospital, Heinrich Heine University Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany.
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12
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Echchannaoui H, Bachmann P, Letiembre M, Espinosa M, Landmann R. Regulation of Streptococcus pneumoniae distribution by Toll-like receptor 2 in vivo. Immunobiology 2005; 210:229-36. [PMID: 16164030 DOI: 10.1016/j.imbio.2005.05.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The phagocyte pattern recognition receptor Toll-like receptor 2 (TLR2) and the multi-receptor adaptor MyD88 contribute to the reduction of bacterial load in infections with intra- and extra-cellular Gram-positive bacteria. Their mechanism of antibacterial action is mostly unresolved but evident in vivo by an increased pathogen burden in infected TLR2-/- and MyD88-/- compared to C57BL/6 wild type (wt) mice. We had previously observed higher bacterial numbers in brains of TLR2-/- than of wt mice with meningitis. Here we study bacteria-phagocyte interaction by comparing S. pneumoniae distribution and localization in wt and TLR2-/- brain by confocal microscopy using a green fluorescent protein-transformed encapsulated S. pneumoniae (C5017). Colony-forming units were similarly distributed in TLR2-/- and wt mice and exclusively localized in meninges and ventricles. Bacteria were more abundant in ventricles, in and around TLR2-/- than wt GLT1v+ plexus choroideus epithelial cells. S. pneumoniae were also found in and around Gr-1+ granulocytes, but never in F4/80+ macrophages, Iba1+ microglia, GFAP+ astrocytes, Meca-31+ endothelial cells or Neun+ neurons of either mouse strain. The results indicate that TLR2 does not change bacterial distribution, but may contribute to antibacterial defense by modulating S. pneumoniae adherence and uptake in plexus epithelia.
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Affiliation(s)
- Hakim Echchannaoui
- Division of Infectious Diseases, Department of Research, University Hospital, Hebelstrasse 20, CH-4031 Basel, Switzerland
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13
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Tenenbaum T, Adam R, Eggelnpöhler I, Matalon D, Seibt A, K Novotny GE, Galla HJ, Schroten H. Strain-dependent disruption of bloodâcerebrospinal fluid barrier byStreptoccocus suisin vitro. ACTA ACUST UNITED AC 2005; 44:25-34. [PMID: 15780575 DOI: 10.1016/j.femsim.2004.12.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2004] [Revised: 09/30/2004] [Accepted: 12/03/2004] [Indexed: 11/26/2022]
Abstract
Streptococcus suis capsular type 2 is an important agent of diseases including meningitis among pigs worldwide, and is also a zoonotic agent. The barrier function of the choroid plexus epithelium that constitutes the structural basis for the blood-cerebrospinal fluid (CSF) barrier has not been elucidated yet in bacterial meningitis. We investigated the influence of various S. suis isolates on the barrier function of cultured porcine choroid plexus epithelial cells with respect to the transepithelial resistance and paracellular [(3)H]-mannitol flux. Preferentially apical application of S. suis isolates significantly decreased transepithelial resistance and significantly increased paracellular [(3)H]-mannitol flux in a time-, dose- and strain-dependent manner. Viable S. suis isolates caused cytotoxicity determined by lactate dehydrogenase assay and electron microscopy, whereas S. suis sonicates and UV-inactivated S. suis did not cause cytotoxicity. The observed effects on porcine choroid plexus epithelial cells barrier function could not exclusively be ascribed to known virulence factors of S. suis such as suilysin. In conclusion, S. suis isolates induce loss of blood-cerebrospinal fluid barrier function in an in vitro model. Thus, S. suis may facilitate trafficking of bacteria and leucocytes across the blood-cerebrospinal fluid barrier. The underlying mechanisms for the barrier breakdown have yet to be determined.
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Affiliation(s)
- Tobias Tenenbaum
- Pediatric Infectious Diseases, Department of General Pediatrics, Heinrich-Heine-University, Düsseldorf, Germany
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