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Atherosclerosis: integration of its pathogenesis as a self-perpetuating propagating inflammation: a review. Cardiovasc Endocrinol Metab 2019; 8:51-61. [PMID: 31588428 DOI: 10.1097/xce.0000000000000172] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 03/29/2019] [Indexed: 12/22/2022]
Abstract
This review proposes that the development of the atherosclerotic plaque is critically dependent on its inflammatory components forming a self-perpetuating and propagating positive feedback loop. The components involved are: (1) LDL oxidation, (2) activation of the endothelium, (3) recruitment of inflammatory monocytes, (4) macrophage accumulation, which induces LDL oxidation, and (5) macrophage generation of inflammatory mediators, which also activate the endothelium. Through these stages, the positive feedback loop is formed, which generates and promotes expansion of the atherosclerotic process. To illustrate this dynamic of lesion development, the author previously produced a computer simulation, which allowed realistic modelling. This hypothesis on atherogenesis can explain the existence and characteristic focal morphology of the atherosclerotic plaque. Each of the components contributing to the feedback loop is discussed. Many of these components also contain subsidiary positive feedback loops, which could exacerbate the overall process.
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Monocytes but Not Lymphocytes Carrying HIV-1 on Their Surface Transmit Infection to Human Tissue Ex Vivo. J Virol 2016; 90:9833-9840. [PMID: 27558419 DOI: 10.1128/jvi.00742-16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 08/15/2016] [Indexed: 12/16/2022] Open
Abstract
Unprotected sexual intercourse with HIV-infected men is the major cause of new infections. HIV virions are released into semen by various cells of the male genital tract, as well as by infected monocytes and lymphocytes present in semen. Some of these virions may attach to the surfaces of cells, infected or uninfected. We investigated whether cells carrying attached HIV on their surfaces can transmit infection. We addressed this question in a model system of human tissue exposed ex vivo to monocytes and lymphocytes carrying HIV on their surfaces. We gamma irradiated the cells to prevent their productive infection. In spite of comparable amounts of HIV attached to monocytes and lymphocytes, only monocytes were capable of transmitting infection and triggering productive infection in tissue. This HIV-1 transmission was mediated by cell-cell contacts. Our experiments suggest that in vivo, HIV attached to infected or uninfected monocytes, which far outnumber lymphocytes in HIV-infected semen, may contribute to sexual transmission of HIV from men to their partners. IMPORTANCE The vast majority of new HIV infections occur through sexual transmission, in which HIV is transferred from the semen of an infected male to an uninfected partner. In semen, HIV-1 particles may exist as free-floating virions; inside infected cells; or attached to the surfaces of cells, whether they are infected or not. Here, we investigated whether HIV attached to the surfaces of monocytes or lymphocytes could transmit infection to human tissue. Incubation of human tissue with monocyte-attached HIV resulted in productive tissue infection. In contrast, there was no infection of tissues when they were incubated with lymphocyte-attached HIV-1. Our results highlight the important role that seminal monocytes may play in HIV transmission in vivo, especially since monocytes far outnumber lymphocytes in the semen of HIV-infected individuals.
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Contini C, Cultrera R, Seraceni S, Castellazzi M, Granieri E, Fainardi E. Cerebrospinal fluid molecular demonstration of Chlamydia pneumoniae DNA is associated to clinical and brain magnetic resonance imaging activity in a subset of patients with relapsing-remitting multiple sclerosis. Mult Scler 2016; 10:360-9. [PMID: 15327030 DOI: 10.1191/1352458504ms1049oa] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
To further explore the link between Chlamydia pneumoniae and multiple sclerosis (MS), we examined cerebrospinal fluid (CSF) samples from 71 patients with MS and from 72 patients suffering from other inflammatory neurological disorders (OIND) or noninflammatory neurological disorders (NIND). All samples were analysed by a touchdown nested polymerase chain reaction (n-PCR) forC. pneumoniae with primer sets which amplify target sequence genes encoding the major outer membrane protein (MOMP), the16S rRNA and the Hsp- 70 protein. A molecular study was also performed to evaluate genetic diversity among isolates of C. pneumoniae and to compare chlamydial sequences. PCR was found positive in 36.6% of total MS, in 28.1% of OIND and in 37.5% of NIND patients, without any statistical differences among the various groups examined. CSF PCR evidence of C. pneumoniae was significantly more frequent in relapsing-remitting (RR) than in secondary progressive (SP) (PB-0.001) and in primary progressive (PP)MS (PB-0.05), in clinically active than in clinically stable MS (PB-0.05) and in MRI active than in MRI inactive MS(PB-0.001). The analysis of CSF expression of each single C. pneumoniae-specific gene revealed that detectable levels of MOMP were significantly more frequent in MS patients with relapse (PB-0.05), whereas PCR positivity for MOMP and 16S rRNA genes were more represented in MS patients with clinical and MRI evidence of disease activity (PB-0.05). Similar rates for MOMP and 16S rRNA genes were detected in CSF of both MS patients and controls, whereas CSF PCR positivity for Hsp-70 gene was observed in only three active RR MS patients. Sequence analysis revealed significant homologies withC. pneumoniae compared to otherChlamydial spp. These findings confirm that theC. pneumoniae detection within the central nervous system (CNS) is not selectively restricted to MS, but accounts in a variety of neurological diseases. In addition, our results suggest that CSF C. pneumoniae-specific DNA detection can occur in a subset of MS patients with clinical and MRI active RR form in whom a C. pneumoniae brain chronic persistent infection may play a significant role in the development of disease.
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Affiliation(s)
- C Contini
- Section of Infectious Diseases, Department of Clinical & Experimental Medicine, University of Ferrara, via Fossato di Mortara, 23, 1-44100 Ferrara, Italy.
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4
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Luessi F, Kraus S, Trinschek B, Lerch S, Ploen R, Paterka M, Roberg T, Poisa-Beiro L, Klotz L, Wiendl H, Bopp T, Jonuleit H, Jolivel V, Zipp F, Witsch E. FTY720 (fingolimod) treatment tips the balance towards less immunogenic antigen-presenting cells in patients with multiple sclerosis. Mult Scler 2015; 21:1811-22. [PMID: 25732840 DOI: 10.1177/1352458515574895] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 01/26/2015] [Indexed: 11/16/2022]
Abstract
OBJECTIVE We aimed to clarify whether fingolimod has direct effects on antigen-presenting cells in multiple sclerosis patients. METHODS Frequency and phenotype of directly ex vivo dendritic cells and monocytes were analyzed in 43 individuals, including fingolimod-treated and untreated multiple sclerosis patients as well as healthy subjects. These cells were further stimulated with lipopolysaccharide to determine functional effects of fingolimod treatment. RESULTS Absolute numbers of CD1c+ dendritic cells and monocytes were not significantly reduced in fingolimod-treated patients indicating that fingolimod did not block the migration of antigen-presenting cells to peripheral blood. CD86 was upregulated on CD1c+ dendritic cells and thus their activation was not impaired under fingolimod treatment. Quantitative analyses of gene transcription in cells and protein content in supernatants from ex vivo CD1c+ dendritic cells and monocytes, however, showed lower secretion of TNFα, IL1-β and IL-6 upon lipopolysaccharide-stimulation. These results could be matched with CD4+MOG-specific transgenic T cells exhibiting reduced levels of TNFα and IFN-γ but not IL-4 upon stimulation with murine dendritic cells loaded with MOG, when treated with fingolimod. CONCLUSIONS Our data indicate that fingolimod - apart from trapping lymphocytes in lymph nodes - exerts its disease-modulating activity by rebalancing the immune tolerance networks by modulation of antigen-presenting cells.
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Affiliation(s)
- Felix Luessi
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany
| | - Stefan Kraus
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany
| | - Bettina Trinschek
- Department of Dermatology, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany
| | - Steffen Lerch
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany
| | - Robert Ploen
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany
| | - Magdalena Paterka
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany
| | - Torsten Roberg
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany
| | - Laura Poisa-Beiro
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany
| | - Luisa Klotz
- Department of Neurology, University of Münster, Germany
| | - Heinz Wiendl
- Department of Neurology, University of Münster, Germany
| | - Tobias Bopp
- Institute for Immunology, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany
| | - Helmut Jonuleit
- Department of Dermatology, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany
| | - Valérie Jolivel
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany
| | - Frauke Zipp
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany
| | - Esther Witsch
- Department of Neurology, University Medical Center of the Johannes Gutenberg-University of Mainz, Germany
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Kalim KW, Groettrup M. Prostaglandin E2 inhibits IL-23 and IL-12 production by human monocytes through down-regulation of their common p40 subunit. Mol Immunol 2012; 53:274-82. [PMID: 22982753 DOI: 10.1016/j.molimm.2012.08.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 08/15/2012] [Indexed: 11/28/2022]
Abstract
The heterodimeric cytokine IL-23 is important for the maintenance of Th17 cells, which are pivotal mediators of autoimmune diseases like rheumatoid arthritis, colitis, and multiple sclerosis. Prostaglandin E2 (PGE2) is a soluble regulator of inflammation that has both pro- and anti-inflammatory properties. PGE2 has been shown to elevate the IL-23 production by dendritic cells (DC). Monocytes are also producers of IL-23 but the effect of PGE2 on IL-23 production by human monocytes has hardly been investigated. We show here that PGE2 blocks the production of IL-23 by LPS-stimulated monocytes in an IL-10 and IL-1β independent manner. This effect was due to the down-regulation of the p40 subunit of IL-23 on mRNA and protein level. The p40 subunit is shared by IL-12 and, consistently, PGE2 also lowered the IL-12 production by monocytes. These effects of PGE2 were cAMP-dependent since the cAMP enhancer forskolin strongly reduced IL-23 and IL-12 production by monocytes. Taken together, PGE2 acts in an anti-inflammatory manner by lowering IL-23 production by monocytes while it has the opposite effect in DC. Our data may help to reconcile controversial point of views on the pro- and anti-inflammatory nature of PGE2 by making a strong case for a cell type-dependent function.
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Affiliation(s)
- Khalid W Kalim
- Division of Immunology, Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
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6
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Paulsson JM, Held C, Jacobson SH, Lundahl J. In vivoExtravasated Human Monocytes have an Altered Expression of CD16, HLA-DR, CD86, CD36 and CX3CR1. Scand J Immunol 2009; 70:368-76. [DOI: 10.1111/j.1365-3083.2009.02306.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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7
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McGettrick HM, Hunter K, Moss PA, Buckley CD, Rainger GE, Nash GB. Direct observations of the kinetics of migrating T cells suggest active retention by endothelial cells with continual bidirectional migration. J Leukoc Biol 2008; 85:98-107. [PMID: 18948550 PMCID: PMC2626767 DOI: 10.1189/jlb.0508301] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The kinetics and regulatory mechanisms of T cell migration through the endothelium have not been fully defined. In experimental, filter-based assays in vitro, transmigration of lymphocytes takes hours, compared with minutes, in vivo. We cultured endothelial cell (EC) monolayers on filters, solid substrates, or collagen gels and treated them with TNF-α, IFN-γ, or both prior to analysis of lymphocyte migration in the presence or absence of flow. PBL, CD4+ cells, or CD8+ cells took many hours to migrate through EC-filter constructs for all cytokine treatments. However, direct microscopic observations of EC filters, which had been mounted in a flow chamber, showed that PBL crossed the endothelial monolayer in minutes and were highly motile in the subendothelial space. Migration through EC was also observed on clear plastic, with or without flow. After a brief settling without flow, PBL and isolated CD3+ or CD4+ cells crossed EC in minutes, but the numbers of migrated cells varied little with time. Close observation revealed that lymphocytes migrated back and forth continuously across endothelium. Under flow, migration kinetics and the proportions migrating back and forth were altered little. On collagen gels, PBL again crossed EC in minutes and migrated back and forth but showed little penetration of the gel over hours. In contrast, neutrophils migrated efficiently through EC and into gels. These observations suggest a novel model for lymphoid migration in which EC support migration but retain lymphocytes (as opposed to neutrophils), and additional signal(s) are required for onward migration.
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Affiliation(s)
- Helen M McGettrick
- The Medical School, The University of Birmingham, Birmingham B15 2TT, UK
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Luu NT, Madden J, Calder PC, Grimble RF, Shearman CP, Chan T, Dastur N, Howell WM, Rainger GE, Nash GB. Dietary supplementation with fish oil modifies the ability of human monocytes to induce an inflammatory response. J Nutr 2007; 137:2769-74. [PMID: 18029497 DOI: 10.1093/jn/137.12.2769] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Monocytes/macrophages are key orchestrators of inflammation and are involved in the pathogenesis of chronic inflammatory disorders, including atherosclerosis. (n-3) Fatty acids, found in fish oil, have been shown to have protective effects in such disorders. To investigate possible modes of action, we used a monocyte:endothelial cell (EC) coculture model to investigate the pro-inflammatory potential of monocytes. Monocytes were isolated from the blood of donors with peripheral arterial disease (PAD) or control donors, before and after a 12-wk supplementation of their diet with fish oil. The monocytes were cultured with human umbilical vein EC (HUVEC) for 24 h, after which the ability of the HUVEC to recruit flowing neutrophils was tested. Monocytes from either group of donors stimulated the EC to support the adhesion and migration of neutrophils. Fish oil supplementation reduced the potency of monocytes from normal subjects, but not those from patients with PAD, to induce recruitment. Concurrent medication may have acted as a complicating factor. On subgroup analysis, only those free of medication showed a significant effect of fish oil. Responses before or after supplementation were not closely linked to patterns of secretion of cytokines by cultured monocytes, tested in parallel monocultures. These results suggest that fish oil can modulate the ability of monocytes to stimulate EC and that this might contribute to their protective effects against chronic inflammatory disorders. Benefits, however, may depend on existing medical status and on other treatments being received.
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Affiliation(s)
- Nguyet-Thin Luu
- Centre for Cardiovascular Sciences, Department of Physiology, The Medical School, University of Birmingham, Birmingham, B15 2TT, UK
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9
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Luu NT, Madden J, Calder PC, Grimble RF, Shearman CP, Chan T, Tull SP, Dastur N, Rainger GE, Nash GB. Comparison of the pro-inflammatory potential of monocytes from healthy adults and those with peripheral arterial disease using an in vitro culture model. Atherosclerosis 2007; 193:259-68. [PMID: 16982061 DOI: 10.1016/j.atherosclerosis.2006.08.050] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Revised: 08/16/2006] [Accepted: 08/24/2006] [Indexed: 10/24/2022]
Abstract
We adapted a monocyte:endothelial cell co-culture model to investigate the pro-inflammatory potential of monocytes from patients with peripheral arterial disease (PAD). Isolated monocytes were cultured with human umbilical vein endothelial cells (HUVEC) for 24h, after which the ability of the HUVEC to recruit flowing neutrophils was tested. Development of a usable protocol required comparisons of primary HUVEC with cells that had been passaged and/or frozen and thawed, evaluation of optimal culture media and comparison of monocytes from freshly drawn and stored blood. We found, for instance, that expansion of HUVEC was assisted by inclusion of hydrocortisone, but this agent was withdrawn before the test phase because it reduced responses of HUVEC. Using the optimal practical protocol, we found great variation in the ability of monocytes from different donors to cause neutrophil adhesion. Slightly more ( approximately 20%) monocytes from patients with PAD adhered to HUVEC than monocytes from healthy controls, and the monocytes from PAD patients induced approximately 70% greater subsequent adhesion of neutrophils. Thus, we developed a functional model of inflammatory potential usable in clinically-related studies and found that patients with PAD had circulating monocytes with greater than normal ability to activate endothelial cells.
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Affiliation(s)
- N T Luu
- Centre for Cardiovascular Sciences, Department of Physiology, Medical School, The University of Birmingham, Birmingham B15 2TT, UK
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Garrood T, Lee L, Pitzalis C. Molecular mechanisms of cell recruitment to inflammatory sites: general and tissue-specific pathways. Rheumatology (Oxford) 2005; 45:250-60. [PMID: 16319101 DOI: 10.1093/rheumatology/kei207] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- T Garrood
- Rheumatology Unit, 5th Floor, Thomas Guy House, Guy's Hospital , London SE1 9RT, UK
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12
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Gilli UO, Schneider MKJ, Loetscher P, Seebach JD. Human polymorphonuclear neutrophils are recruited by porcine chemokines acting on CXC chemokine receptor 2, and platelet-activating factor. Transplantation 2005; 79:1324-31. [PMID: 15912099 DOI: 10.1097/01.tp.0000155429.44902.44] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Pig-to-human xenotransplantation is hampered by strong humoral and cellular immune responses, including acute vascular rejection (AVR). Infiltration of vascular xenografts by recipient polymorphonuclear neutrophils (PMN) is an early feature of AVR. Since little is known about the initiation of PMN recruitment, the present study investigated whether activated porcine endothelial cells (EC) release factors that induce human PMN recruitment. METHODS Primary and immortalized porcine aortic EC cultures were stimulated with phorbol-myristate acetate/ionomycin, lipopolysaccharide, tumor-necrosis factor-alpha, or interferon-gamma. The interleukin (IL)-8 concentration of porcine EC supernatants was tested by ELISA. Human and porcine PMN were isolated from peripheral blood by Ficoll sedimentation and centrifugation, characterized by morphology and flow cytometry, and analyzed for chemotaxis using Boyden chambers or Transwells. PMN chemokine receptor desensitization was determined by intracellular calcium-flux measurements. RESULTS Porcine EC supernatants contained significant amounts of porcine IL-8 and triggered chemotaxis in both human and porcine PMN. Chemotaxis of porcine, but not human, PMN was inhibited by anti-porcine IL-8 antibodies and recombinant porcine IL-8 induced strong chemotaxis only in porcine PMN. Porcine EC supernatants desensitized human PMN CXC-chemokine receptor (CXCR) 2, but not CXCR1, a receptor for human IL-8. Human PMN chemotaxis induced by porcine EC supernatants was significantly inhibited by blocking CXCR2 and platelet-activating factor (PAF). CONCLUSIONS Both chemokines acting via CXCR2 and PAF are released by porcine EC inducing efficient chemotaxis of human PMN. These mechanisms responsible for the recruitment of human PMN to porcine endothelium during cell-mediated rejection of xenografts represent potential targets for preventive strategies.
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Affiliation(s)
- Urs O Gilli
- Laboratory for Transplantation Immunology, Department for Internal Medicine, University Hospital Zurich, Zurich, Switzerland
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13
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Lechat E, Milhau N, Brun P, Bellaton C, Greenland T, Mornex JF, Le Jan C. Goat endothelial cells may be infected in vitro by transmigration of caprine arthritis-encephalitis virus-infected leucocytes. Vet Immunol Immunopathol 2005; 104:257-63. [PMID: 15734546 DOI: 10.1016/j.vetimm.2004.12.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2004] [Revised: 11/30/2004] [Accepted: 12/02/2004] [Indexed: 11/26/2022]
Abstract
The caprine arthritis-encephalitis lentivirus (CAEV) causes a lifelong persistent infection in goats, and induces infiltrations of leucocytes and tissue reorganization in target organs, with a cyclical pattern of viral expression. The mammary gland is an important site of infection, associated with mother-to-kid transmission by infected cells in colostrum and milk. The monocyte/macrophage is the principal target cell, but other cell types, including epithelial and endothelial cells and fibroblasts, are susceptible to in vitro infection with varying levels of viral replication. Such cells, perhaps at specific differentiation states, might play a role in the regulation and transfer of in vivo infection in target organs. In this paper we describe the in vitro infection of endothelial cell monolayers by the transmigration of monocytes carrying the CAEV provirus. The infected endothelial cells progress to expression of the viral p30 capsid antigen, suggesting viral proliferation. Such a process occurring in vivo during angiogenesis and leucocyte homing to the mammary gland in the final third of mammogenesis, might contribute to viral spread in this crucial target organ.
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Affiliation(s)
- E Lechat
- UMR 754, Rétrovirus et Pathologie comparée, INRA/UCBL/ENVL/EPHE, IFR 128 Biosciences Lyon Gerland, Université Claude Bernard, 50 Avenue Tony Garnier, 69366 Lyon Cedex 07, France
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14
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Stone PCW, Lally F, Rahman M, Smith E, Buckley CD, Nash GB, Rainger GE. Transmigrated neutrophils down‐regulate the expression of VCAM‐1 on endothelial cells and inhibit the adhesion of flowing lymphocytes. J Leukoc Biol 2004; 77:44-51. [PMID: 15459233 DOI: 10.1189/jlb.0504304] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
As the first leukocytes recruited during inflammation, neutrophils are ideally situated to regulate the subsequent recruitment of mononuclear leukocytes. Here, we found that human neutrophils recruited by endothelial cells (EC), which had been stimulated with tumor necrosis factor alpha for 4 h, inhibited the adhesion of flowing, mixed mononuclear cells or purified lymphocytes over the subsequent 20 h but did not affect the adhesion of a secondary bolus of neutrophils. The degree of inhibition of lymphocyte adhesion increased with the duration of neutrophil-EC contact and with the number of recruited neutrophils. Antibody-blocking studies showed that lymphocyte adhesion was mediated predominantly by vascular cell adhesion molecule-1 (VCAM-1). Recruited neutrophils reduced the EC expression of VCAM-1 but not intercellular adhesion molecule-1 (ICAM-1) or E-selectin in a manner that mirrored the time- and number-dependent reduction in lymphocyte adhesion. VCAM-1 was not shed into the culture supernatant, and a panel of protease inhibitors was unable to reverse its down-regulation, indicating that it was not proteolytically degraded by neutrophils. In EC that had been in contact with neutrophils, the mRNA message for VCAM-1 but not ICAM-1 was down-regulated, indicating that alterations in transcriptional activity were responsible for the reduction in VCAM-1. Thus, under some inflammatory milieu, neutrophils may delay the recruitment of mononuclear leukocytes by regulating the expression of EC adhesion receptors.
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Affiliation(s)
- Philip C W Stone
- Department of Physiology, The Medical School, The University of Birmingham, Edgbaston, Birmingham, UK B15 2TT
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15
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Séguin R, Biernacki K, Rotondo RL, Prat A, Antel JP. Regulation and functional effects of monocyte migration across human brain-derived endothelial cells. J Neuropathol Exp Neurol 2003; 62:412-9. [PMID: 12722833 DOI: 10.1093/jnen/62.4.412] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have used human brain-derived endothelial cells (HBECs) maintained under basal culture conditions in a Boyden chamber assay system as an in vitro model of migration of cells of systemic immune origin across the blood brain barrier (BBB) during the initiation of a CNS-directed inflammatory response. In this study we evaluated the molecular mechanisms that regulate passage of ex vivo peripheral blood-derived monocytes across this barrier and the effects of such migration on the properties of both the HBECs and the monocytes. Our results indicate that monocytes can migrate across HBECs in the absence of inflammatory conditions, at rates exceeding those of lymphocytes. Monocyte migration could be significantly inhibited by the addition of blocking antibodies to intercellular adhesion molecule (ICAM)-1, very late antigen (VLA)-4 integrin, and monocyte chemoattractant protein (CCL-2/MCP-1), or treatment with tissue inhibitor of metalloproteinase (TIMP-1). Following monocyte migration there was a significant increase in permeability of soluble molecules and an enhanced rate of T cell migration across HBECs. The enhanced permeability could be partially prevented with anti-TNF-alpha antibody. The migration process did not induce the upregulation of either co-stimulatory molecules or chemokine receptors on the monocytes. These studies emphasize the functional role of monocyte-endothelial interactions in permitting target access of a CNS-directed cell-mediated immune response.
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Affiliation(s)
- Rosanne Séguin
- Neuroimmunology Unit, Montreal Neurological Institute, Montreal, Quebec, Canada
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16
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Stoy NS. Monocyte/macrophage initiation of organ-specific autoimmunity: the ultimate 'bystander' hypothesis? Med Hypotheses 2002; 58:312-26. [PMID: 12027526 DOI: 10.1054/mehy.2001.1547] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
It is postulated that organ-specific autoimmune diseases could be initiated by dysregulated peripherally activated monocytes/macrophages penetrating into target organs nonspecifically. Failure of regulation of pro-inflammatory monocytes/macrophages might then result in autoimmune disease if secondary over-expansion of pre-existing autoantigen-specific T cell populations occurs in genetically predisposed individuals.
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MESH Headings
- Animals
- Antigen Presentation
- Arthritis, Rheumatoid/immunology
- Arthritis, Rheumatoid/pathology
- Autoimmune Diseases/immunology
- Autoimmune Diseases/pathology
- Autoimmunity/physiology
- Cell Adhesion
- Cell Movement
- Cytokines/physiology
- Dendritic Cells/immunology
- Dendritic Cells/pathology
- Diabetes Mellitus, Type 1/immunology
- Diabetes Mellitus, Type 1/pathology
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Endothelium, Vascular/physiopathology
- Genetic Predisposition to Disease
- Humans
- Infections/complications
- Infections/immunology
- Inflammation/immunology
- Lymphocyte Subsets/immunology
- Macrophage Activation
- Macrophages/pathology
- Mice
- Mice, Inbred NOD
- Models, Animal
- Models, Immunological
- Monocytes/pathology
- Multiple Sclerosis/immunology
- Multiple Sclerosis/pathology
- Organ Specificity
- Rats
- Rats, Mutant Strains
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Affiliation(s)
- N S Stoy
- Royal Hospital for Neuro-disability, West Hill, Putney, London, UK
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Nikkilä HV, Müller K, Ahokas A, Rimón R, Andersson LC. Increased frequency of activated lymphocytes in the cerebrospinal fluid of patients with acute schizophrenia. Schizophr Res 2001; 49:99-105. [PMID: 11343869 DOI: 10.1016/s0920-9964(99)00218-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We compared the cerebrospinal fluid (CSF) cytology of 30 acutely psychotic patients at the initial phase of their hospital treatment with that of 46 control individuals with no psychiatric disorder or central nervous system (CNS) disease. The cytological profile of May-Grünwald-Giemsa stained CSF cell slides of the patients was significantly different from that of the control population. The most striking finding was a significantly increased frequency of lymphoid cells showing morphological features of activation/stimulation and a decreased proportion of normal small lymphocytes. Many of the cells with aberrant morphology displayed structural details similar to those of the 'P cells' previously described in the blood of schizophrenic patients. The patients' CSF also contained elevated proportions of monocytes/macrophages, some of which were found in 'rosettes' with activated lymphocytes indicating an increased intercellular adhesion. Possible pathogenic mechanisms behind lymphocyte activation and macrophage dominance in the CSF of acutely ill psychotic patients are discussed.
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Affiliation(s)
- H V Nikkilä
- Department of Psychiatry, Helsinki University, Lapinlahdentie 1, 00180, Helsinki, Finland.
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18
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Kouwenhoven M, Teleshova N, Ozenci V, Press R, Link H. Monocytes in multiple sclerosis: phenotype and cytokine profile. J Neuroimmunol 2001; 112:197-205. [PMID: 11108949 DOI: 10.1016/s0165-5728(00)00396-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Multiple sclerosis (MS) is an inflammatory demyelinating disease characterised by immune abnormalities in the central nervous system (CNS) as well as systemically. Activated, blood-borne monocytes are abundant in MS lesions, the properties of circulating monocytes are incompletely known. To delineate phenotype and levels of cytokine secreting monocytes in MS patients' blood, ELISPOT assays were used for detection and enumeration of monocytes secreting the cytokines IL-6, IL-12, TNF-alpha and IL-10. In parallel, the expression by monocytes of co-stimulatory molecules (CD40, CD80, CD86), major histocompatibility complex molecules (HLA-ABC, HLA-DR) and Fcgamma receptors (CD16, CD64) was examined by flow cytometry. Levels of blood monocytes secreting IL-6 and IL-12 were higher in patients with untreated MS and other neurological diseases (OND) compared to healthy controls, while levels of monocytes secreting TNF-alpha and IL-10 did not differ between groups. MS patients' blood monocytes also displayed elevated mean fluorescence intensity for the co-stimulatory molecule CD86, and MS patients with longer disease duration (>10 years) and higher disease severity (EDSS >3) had higher percentages of CD80 expressing monocytes compared to patients with short duration or lower severity. In conclusion, monocyte aberrations occur in MS and may change over the disease course.
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Affiliation(s)
- M Kouwenhoven
- Neuroimmunology Unit, Division of Neurology, Karolinska Institutet, Huddinge University Hospital, Stockholm, Sweden.
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19
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Verdrengh M, Lindberg FP, Ryden C, Tarkowski A. Integrin-associated protein (IAP)-deficient mice are less susceptible to developing Staphylococcus aureus-induced arthritis. Microbes Infect 1999; 1:745-51. [PMID: 10816079 DOI: 10.1016/s1286-4579(99)80076-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The integrin-associated protein (IAP) has been shown to function in a signaling complex with beta3 integrins, influencing the migration of phagocytic cells into inflamed tissues. We have previously shown that gene-targeted mice deficient for IAP succumbed to peritonitis when inoculated with gram-negative bacteria. The aim of this study was to assess the role of IAP in our recently established model of haematogenously induced Staphylococcus aureus septicaemia and arthritis. In this model, neutrophils play a crucial role in the early phase of the infection. Mice lacking IAP and congenic controls were intravenously inoculated with S. aureus LS-1. The IAP-/- mice were resistant to developing clinical signs of arthritis compared with their IAP-expressing littermates. The clinical findings were corroborated by histopathological evaluation indicating that the IAP-/- mice had less cartilage and bone destruction in the joints. We believe that a delayed migration of leukocytes into the joints of mice lacking IAP expression leads to decreased susceptibility to develop S. aureus-induced arthritis.
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Affiliation(s)
- M Verdrengh
- Department of Rheumatology, University of Göteborg, Sweden
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20
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Lawson C, Ainsworth M, Yacoub M, Rose M. Ligation of ICAM-1 on Endothelial Cells Leads to Expression of VCAM-1 Via a Nuclear Factor-κB-Independent Mechanism. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.162.5.2990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
ICAM-1 is an Ig-like cell adhesion molecule expressed by several cell types, including the endothelium. Cross-linking of ICAM-1 on the surface of different cell types has previously been shown to cause an increase in cellular activation within the cytoplasm. In this study, we have compared signaling events following ligation of ICAM-1 by cross-linking with mAbs with events after activation of HUVEC by TNF. ICAM-1 cross-linking caused activation of Erk-1 and the AP-1 transcription factor complex, without any increase in NF-κB activity, in contrast to TNF stimulation. Transcription of VCAM-1 mRNA was observed by reverse-transcriptase PCR after ICAM-1 cross-linking, with no associated transcription of E-selectin. This was reflected by the presence of VCAM-1 protein after immunoprecipitation, without E-selectin expression, in ICAM-1 cross-linked cells. In contrast, mRNA and protein for both VCAM-1 and E-selectin were observed in TNF-treated HUVEC, as expected. Addition of the MEK (MAP/Erk kinase) inhibitor PD98059 reduced expression of VCAM-1 after ICAM-1 cross-linking, suggesting that the Erk pathway is involved in ICAM-1-mediated VCAM-1 expression. In conclusion, ICAM-1-induced expression of VCAM-1 represents a pathway for adhesion molecule up-regulation that is distinct from the TNF-induced pathway. It may be similar to the IL-4 pathway or it may represent a novel pathway.
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Affiliation(s)
- Charlotte Lawson
- Department of Cardiothoracic Surgery, National Heart and Lung Institute, Imperial College School of Medicine, Heart Science Centre, Harefield Hospital, Harefield, Middlesex, United Kingdom
| | - Mark Ainsworth
- Department of Cardiothoracic Surgery, National Heart and Lung Institute, Imperial College School of Medicine, Heart Science Centre, Harefield Hospital, Harefield, Middlesex, United Kingdom
| | - Magdi Yacoub
- Department of Cardiothoracic Surgery, National Heart and Lung Institute, Imperial College School of Medicine, Heart Science Centre, Harefield Hospital, Harefield, Middlesex, United Kingdom
| | - Marlene Rose
- Department of Cardiothoracic Surgery, National Heart and Lung Institute, Imperial College School of Medicine, Heart Science Centre, Harefield Hospital, Harefield, Middlesex, United Kingdom
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