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Trifunovic S, Stevanovic I, Milosevic A, Ristic N, Janjic M, Bjelobaba I, Savic D, Bozic I, Jakovljevic M, Tesovic K, Laketa D, Lavrnja I. The Function of the Hypothalamic-Pituitary-Adrenal Axis During Experimental Autoimmune Encephalomyelitis: Involvement of Oxidative Stress Mediators. Front Neurosci 2021; 15:649485. [PMID: 34220419 PMCID: PMC8248369 DOI: 10.3389/fnins.2021.649485] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 04/29/2021] [Indexed: 12/26/2022] Open
Abstract
Multiple sclerosis (MS) is an inflammatory, demyelinating disease with an unknown origin. Previous studies showed the involvement of the hypothalamic–pituitary–adrenal (HPA) axis to susceptibility to autoimmune diseases, including MS, and its best-characterized animal model, experimental autoimmune encephalomyelitis (EAE). During MS/EAE, innate immune cells are activated and release cytokines and other inflammatory mediators, leading to a vicious cycle of inflammation. In response to inflammation, the activated HPA axis modulates immune responses via glucocorticoid activity. Because the mechanisms involving oxidative stress to the HPA axis are relatively unrevealed, in this study, we investigate the inflammatory and oxidative stress status of HPA axis during EAE. Our results reveal an upregulation of Pomc gene expression, followed by POMC and ACTH protein increase at the peak of the EAE in the pituitary. Also, prostaglandins are well-known contributors of HPA axis activation, which increases during EAE at the periphery. The upregulated Tnf expression in the pituitary during the peak of EAE occurred. This leads to the activation of oxidative pathways, followed by upregulation of inducible NO synthase expression. The reactive oxidant/nitrosative species (ROS/RNS), such as superoxide anion and NO, increase their levels at the onset and peak of the disease in the pituitary and adrenal glands, returning to control levels at the end of EAE. The corticotrophs in the pituitary increased in number and volume at the peak of EAE that coincides with high lipid peroxidation levels. The expression of MC2R in the adrenal glands increases at the peak of EAE, where strong induction of superoxide anion and malondialdehyde (MDA), reduced total glutathione (GSH) content, and catalase activity occurred at the peak and end of EAE compared with controls. The results obtained from this study may help in understanding the mechanisms and possible pharmacological modulation in MS and demonstrate an effect of oxidative stress exposure in the HPA activation during the course of EAE.
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Affiliation(s)
- Svetlana Trifunovic
- Institute for Biological Research "Siniša Stanković"-National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Ivana Stevanovic
- Medical Faculty of Military Medical Academy, Institute of Medical Research Belgrade, University of Defense, Belgrade, Serbia
| | - Ana Milosevic
- Institute for Biological Research "Siniša Stanković"-National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Natasa Ristic
- Institute for Biological Research "Siniša Stanković"-National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Marija Janjic
- Institute for Biological Research "Siniša Stanković"-National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Ivana Bjelobaba
- Institute for Biological Research "Siniša Stanković"-National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Danijela Savic
- Institute for Biological Research "Siniša Stanković"-National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Iva Bozic
- Institute for Biological Research "Siniša Stanković"-National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Marija Jakovljevic
- Institute for Biological Research "Siniša Stanković"-National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Katarina Tesovic
- Institute for Biological Research "Siniša Stanković"-National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Danijela Laketa
- Department for General Physiology and Biophysics, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Irena Lavrnja
- Institute for Biological Research "Siniša Stanković"-National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
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Theiss-Suennemann J, Jörß K, Messmann JJ, Reichardt SD, Montes-Cobos E, Lühder F, Tuckermann JP, AWolff H, Dressel R, Gröne HJ, Strauß G, Reichardt HM. Glucocorticoids attenuate acute graft-versus-host disease by suppressing the cytotoxic capacity of CD8(+) T cells. J Pathol 2015; 235:646-55. [PMID: 25358639 DOI: 10.1002/path.4475] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 10/09/2014] [Accepted: 10/29/2014] [Indexed: 01/15/2023]
Abstract
Glucocorticoids (GCs) are released from the adrenal gland during inflammation and help to keep immune responses at bay. Owing to their potent anti-inflammatory activity, GCs also play a key role in controlling acute graft-versus-host disease (aGvHD). Here we demonstrate that mice lacking the glucocorticoid receptor (GR) in T cells develop fulminant disease after allogeneic bone marrow transplantation. In a fully MHC-mismatched model, transfer of GR-deficient T cells resulted in severe aGvHD symptoms and strongly decreased survival times. Histopathological features were aggravated and infiltration of CD8(+) T cells into the jejunum was increased when the GR was not expressed. Furthermore, serum levels of IL-2, IFNγ, and IL-17 were elevated and the cytotoxicity of CD8(+) T cells was enhanced after transfer of GR-deficient T cells. Short-term treatment with dexamethasone reduced cytokine secretion but neither impacted disease severity nor the CTLs' cytolytic capacity. Importantly, in an aGvHD model in which disease development exclusively depends on the presence of CD8(+) T cells in the transplant, transfer of GR-deficient T cells aggravated clinical symptoms and reduced survival times as well. Taken together, our findings highlight that suppression of CD8(+) T-cell function is a crucial mechanism in the control of aGvHD by endogenous GCs.
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Affiliation(s)
- Jennifer Theiss-Suennemann
- Institute for Cellular and Molecular Immunology, University of Göttingen Medical School, Göttingen, Germany
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3
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Abstract
Glucocorticoids exert a variety of immunomodulatory activities. Since changes in glucocorticoid homeostasis impact on susceptibility to autoimmune diseases, and synthetic glucocorticoids are widely used in the treatment of multiple sclerosis, a detailed understanding of their mechanism of action is desirable. Experimental autoimmune encephalomyelitis is a common animal model that mirrors many hallmarks of multiple sclerosis, a chronic inflammatory disease of the CNS with presumed autoimmune origin. Experimental autoimmune encephalomyelitis has been instrumental for many years in studying multiple sclerosis, revealing the blood-brain barrier, the microglia and T-cell apoptosis as major targets of glucocorticoids in this disease. Despite the great advances in the field, the answers to many questions concerning the mechanism of glucocorticoids; for example, the contribution of nongenomic effects or the cell-type specificity of their action, remain elusive. This review will critically discuss what we have learned so far from the analysis of animal models of the molecular mode of therapeutic and endogenous glucocorticoid action in multiple sclerosis. With this knowledge in mind, we should be able to further improve the management of multiple sclerosis using this class of drugs.
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Affiliation(s)
- Holger M Reichardt
- University of Würzburg, Molecular Immunology, Institute for Virology and Immunobiology, Versbacher Strasse 7, 97078 Würzburg, Germany.
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Abstract
Fas is a transmembrane receptor involved in the death program of several cell lines, including T lymphocytes. Deleterious mutations hitting genes involved in the Fas pathway cause the autoimmune lymphoprolipherative syndrome (ALPS). Moreover, defective Fas function is involved in the development of common autoimmune diseases, including autoimmune syndromes hitting the nervous system, such as multiple sclerosis (MS) and chronic inflammatory demyelinating polyneuropathy (CIDP). In this review, we first explore some peculiar aspects of Fas mediated apoptosis in the central versus peripheral nervous system (CNS, PNS); thereafter, we analyze what is currently known on the role of T cell apoptosis in both MS and CIDP, which, in this regard, may be seen as two faces of the same coin. In fact, we show that, in both diseases, defective Fas mediated apoptosis plays a crucial role favoring disease development and its chronic evolution.
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Affiliation(s)
- C Comi
- Department of Clinical and Experimental Medicine, Section of Neurology, Amedeo Avogadro University, Novara, Italy.
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5
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Abstract
Glucocorticoids (GCs) are widely used to treat inflammatory diseases such as multiple sclerosis (MS). They predominantly act through the GC receptor, a member of the nuclear receptor superfamily that controls transcription by several different mechanisms. Owing to its ubiquitous expression, there are a variety of cell types that could serve as GC targets in the pathogenesis and treatment of MS. This brings about a great diversity of mechanisms potentially involved in the modulation of neuroinflammation by GCs, including the induction of apoptosis, repression of pro-inflammatory mediators and the expansion of myeloid-derived suppressor cells. Nevertheless, it is not well understood which of these mechanisms are essential for therapeutic efficacy. In this review, we summarise findings made concerning the actions of GCs in MS and its animal model experimental autoimmune encephalomyelitis, and also elucidate current concepts and developments that pertain to this clinically highly relevant treatment regimen.
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Affiliation(s)
- N Schweingruber
- Department of Cellular and Molecular Immunology, University of Göttingen Medical School, Germany
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Esposito M, Ruffini F, Bergami A, Garzetti L, Borsellino G, Battistini L, Martino G, Furlan R. IL-17- and IFN-γ-secreting Foxp3+ T cells infiltrate the target tissue in experimental autoimmunity. J Immunol 2010; 185:7467-73. [PMID: 21098230 DOI: 10.4049/jimmunol.1001519] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
CD4(+)Foxp3(+) regulatory T cells (Tregs) have been considered crucial in controlling immune system homeostasis, and their derangement is often associated to autoimmunity. Tregs identification is, however, difficult because most markers, including CD25 and Foxp3, are shared by recently activated T cells. We show in this paper that CD4(+)Foxp3(+) T cells are generated in peripheral lymphoid organs on immunization and readily accumulate in the target organ of an autoimmune reaction, together with classical inflammatory cells, constituting up to 50% of infiltrating CD4(+) T cells. Most CD4(+)Foxp3(+) T cells are, however, CD25(-) and express proinflammatory cytokines such as IL-17 and IFN-γ, questioning their suppressive nature. Moreover, in vitro CD4(+) T lymphocytes from naive and autoimmune mice, stimulated to differentiate into Th1, Th2, Th17, and induced Tregs, display early mixed expression of lineage-specific markers. These results clearly point to an unprecedented plasticity of naive CD4(+) T cells, that integrating inflammatory signals may change their fate from the initial lineage commitment to a different functional phenotype.
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Affiliation(s)
- Marianna Esposito
- Clinical Neuroimmunology Unit, Institute of Experimental Neurology, San Raffaele Scientific Institute, Milan, Italy
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7
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Abstract
Post-traumatic immune suppression renders individuals with spinal cord injury (SCI) susceptible to infection. Normally, proper immune function is regulated by collaboration between the sympathetic nervous system (SNS) and hypothalamic-pituitary-adrenal (HPA) axis and involves the controlled release of glucocorticoids (GCs) and norepinephrine (NE). Recently, we showed that after high thoracic (T3) SCI, aberrant levels of GCs and NE accumulate in the blood and spleen, respectively. These changes are associated with splenic atrophy, splenic leucopenia, increased intrasplenic caspase 3 levels, and suppressed B lymphocyte function. As GCs boost SNS function, in part by increasing the expression and affinity of beta2 adrenergic receptors (beta2ARs) while simultaneously preventing beta2AR down-regulation, we predicted that surges in stress hormones (i.e., GCs and NE) in the blood and spleen of mice with high-level SCI would act concurrently to adversely affect lymphocyte function and survival. Here, we show that post-SCI concentrations of GCs enhance the sensitivity of lymphocytes to beta2AR stimulation causing an increase in intracellular Bcl-2 interacting mediator of cell death (Bim) and subsequent apoptosis. In vivo, the combined antagonism of GC receptors and beta2ARs significantly diminished lymphocyte Bim levels and SCI-induced splenic lymphopenia. Together, these data suggest that pharmacological antagonists of the HPA/SNS axes should be considered as adjunct therapies for ameliorating post-traumatic immune suppression in quadriplegics and high paraplegics.
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Affiliation(s)
- Kurt M Lucin
- Department of Molecular Virology, The Ohio State University College of Medicine, Columbus, Ohio, USA
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Yao Z, Dubois DC, Almon RR, Jusko WJ. Pharmacokinetic/pharmacodynamic modeling of corticosterone suppression and lymphocytopenia by methylprednisolone in rats. J Pharm Sci 2008; 97:2820-32. [PMID: 17828751 PMCID: PMC3726057 DOI: 10.1002/jps.21167] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Adrenal suppression and lymphocytopenia are commonly monitored pharmacological responses during systemic exposure to exogenously administered corticosteroids. The pharmacodynamics of plasma corticosterone (CS) and blood lymphocytes were investigated in 60 normal rats which received either 50 mg/kg methylprednisolone (MPL) or vehicle intramuscularly. Blood samples were collected between 0.5 and 96 h following treatment. Plasma CS displayed a transient suppression with re-establishment of a normal circadian rhythm 24 h following drug treatment. An indirect response model with suppression of production well captured plasma CS profiles. An early stress-induced rise in CS was also factored into the model. Blood lymphocyte numbers exhibited a sharp decline and then returned to a new circadian rhythm which was half of the original baseline level. An integrated pharmacodynamic (PD) model with inhibition of lymphocyte trafficking from tissue to blood by both MPL and CS and induction of cell apoptosis by MPL reasonably captured this lymphocytopenia. Rats and humans differ in lymphocyte responses with humans showing full recovery of baselines. Modeling provides a valuable tool in quantitative assessment of dual, complex drug responses.
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Affiliation(s)
- Zhenling Yao
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, State University of New York at Buffalo, 565 Hochstetter Hall, Buffalo, NY 14260
| | - Debra C. Dubois
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, State University of New York at Buffalo, 565 Hochstetter Hall, Buffalo, NY 14260
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, New York
| | - Richard R. Almon
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, State University of New York at Buffalo, 565 Hochstetter Hall, Buffalo, NY 14260
- Department of Biological Sciences, University at Buffalo, State University of New York, Buffalo, New York
| | - William J. Jusko
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, State University of New York at Buffalo, 565 Hochstetter Hall, Buffalo, NY 14260
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Zehntner SP, Bourbonnière L, Moore CS, Morris SJ, Methot D, St Jean M, Lacasse E, Hebb ALO, Robertson GS, Durkin J, Gillard JW, Owens T. X-linked inhibitor of apoptosis regulates T cell effector function. J Immunol 2008; 179:7553-60. [PMID: 18025200 DOI: 10.4049/jimmunol.179.11.7553] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To understand how the balance between pro- and anti-apoptotic signals influences effector function in the immune system, we studied the X-linked inhibitor of apoptosis (XIAP), an endogenous regulator of cellular apoptosis. Real-time PCR showed increased XIAP expression in blood of mice with experimental autoimmune encephalomyelitis, correlating with disease severity. Daily administration (10 mg/kg/day i.p.) of a 19-mer antisense oligonucleotide specific for XIAP (ASO-XIAP) abolished disease-associated XIAP mRNA and protein expression, and given from day of onset, alleviated experimental autoimmune encephalomyelitis and prevented relapses. Prophylactic treatment also reduced XIAP expression and prevented disease. Random or 5-base mismatched ASO was not inhibitory, and ASO-XIAP did not affect T cell priming. In ASO-XIAP-treated animals, infiltrating cells and inflammatory foci were dramatically reduced within the CNS. Flow cytometry showed an 88-93% reduction in T cells. The proportion of TUNEL(+) apoptotic CD4(+) T cells in the CNS was increased from <1.6 to 26% in ASO-XIAP-treated mice, and the proportion of Annexin V-positive CD4(+) T cells in the CNS increased. Neurons and oligodendrocytes were not affected; neither did apoptosis increase in liver, where XIAP knockdown also occurred. ASO-XIAP increased susceptibility of T cells to activation-induced apoptosis in vitro. Our results identify XIAP as a critical controller of apoptotic susceptibility of effector T cell function.
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Affiliation(s)
- Simone P Zehntner
- Neuroimmunology Unit, Montreal Neurological Institute, McGill University, Montreal, Canada.
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10
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Welsh CJ, Young CR. Autoimmune Processes in the Central Nervous System. Handbook of Neurochemistry and Molecular Neurobiology 2008. [DOI: 10.1007/978-0-387-30398-7_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In this chapter we discuss the factors that contribute to the unique immunological environment of the central nervous system and the mechanisms that may account for the development of autoimmunity within the CNS, including infectious agents as inducers of autoimmune disease. Consideration is given to a variety of human neurological diseases of autoimmune or presumed autoimmune etiology: autism, neuromyelitis optica, neuromyotonia, schizophrenia, lethargic encephalitis and stiff‐man syndrome. Also, we discuss autoimmunity as a possible mediator of CNS repair and examples of the protective effects of bacterial and helminth infections on CNS disease. Multiple sclerosis and models of multiple sclerosis are discussed with special attention given to the Theiler's virus‐induced demyelination model.
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11
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Pender MP. Treating autoimmune demyelination by augmenting lymphocyte apoptosis in the central nervous system. J Neuroimmunol 2007; 191:26-38. [PMID: 17931708 DOI: 10.1016/j.jneuroim.2007.09.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Accepted: 09/07/2007] [Indexed: 01/06/2023]
Abstract
The elimination of autoreactive T cells from the central nervous system (CNS) by apoptosis plays an important role in switching off autoimmune attack. B-cell apoptosis in the CNS probably also has a key role in downregulating autoimmunity. Augmenting lymphocyte apoptosis in the CNS is a potential strategy for treating autoimmune CNS diseases such as multiple sclerosis. These strategies involve modulation of the physiological pro-apoptotic and anti-apoptotic pathways that control lymphocyte fate in the CNS. In the case of T cells, apoptosis can be augmented by enhancing activation-induced T-cell apoptosis through the CD95 (Fas) pathway and by inhibiting costimulation-induced anti-apoptotic pathways mediated through BCL-2 and BCL-X L.
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Affiliation(s)
- Michael P Pender
- Neuroimmunology Research Centre, School of Medicine, The University of Queensland, Australia.
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12
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Abstract
Glucocorticoids are a class of steroid hormones that are endowed with profound anti-inflammatory and immunosuppressive activities. Endogenous glucocorticoids are key players in the modulation of the immune system and establish an endocrine basis of many inflammatory diseases. In addition, synthetic glucocorticoids are amongst the most commonly prescribed drugs worldwide for the treatment of autoimmune disorders. In this review we summarize our present knowledge on the mechanisms by which glucocorticoids impact on multiple sclerosis (MS), a highly prevalent neuroinflammatory disease, and its animal model experimental autoimmune encephalomyelitis (EAE). In spite of the new methodologies that have become available during recent years, we are still far from a comprehensive picture of the mechanism by which glucocorticoids control neuroinflammation.
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Affiliation(s)
- Denise Tischner
- University of Göttingen, Medical School, Department of Cellular and Molecular Immunology, Humboldtallee 34, 37073 Göttingen, Germany
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13
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Abstract
T cell apoptosis has been studied in animal models for human autoimmune disorders of the nervous system and in other tissues devoid of specialized immune-defense mechanisms. Our data suggest that the central nervous system has a high potential to eliminate T cell inflammation, whereas this mechanism is less effective in the peripheral nervous system, and even more in muscle and skin. In-vitro experiments indicate different scenarios how specific cellular and humoral elements in the nervous system may synergize and sensitize T cells for apoptosis in-vivo. Probably release of TNF-alpha in the nervous system is a central mechanism to limit inflammation in the brain. This is further substantiated since neutralization of TNF-alpha in MS patients increased cellular inflammation and relapses. Therapeutically several conventional and novel approaches like glucocorticosteroids and high-dose antigen therapy induce T cell apoptosis in-situ. We also discuss regulatory, proapoptotic mechanisms such as the Fas/FasL system and counterregulatory mechanisms that have been utilized to limit tissue damage.
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Affiliation(s)
- R Gold
- Department of Neurology, St. Josef Hospital, Ruhr University Bochum, Gudrunstrasse 56, 44791 Bochum, Germany.
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Dimitrijević M, Rauski A, Radojević K, Kosec D, Stanojević S, Pilipović I, Leposavić G. Beta-adrenoceptor blockade ameliorates the clinical course of experimental allergic encephalomyelitis and diminishes its aggravation in adrenalectomized rats. Eur J Pharmacol 2007; 577:170-82. [PMID: 17854797 DOI: 10.1016/j.ejphar.2007.08.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 08/07/2007] [Accepted: 08/16/2007] [Indexed: 01/30/2023]
Abstract
As glucocorticoids influence both catecholamine synthesis and adrenoceptor expression by immune cells, the current study was undertaken to distinguish their direct effects on the development of experimental allergic encephalomyelitis from those induced by alteration of catecholamine signaling. We examined the influence of 16-day-long beta-adrenoceptor blockade with propranolol (0.40 mg/100 g body weight/day, s.c.) beginning 3 days before immunization on the development of experimental allergic encephalomyelitis in adrenalectomized (7 days before immunization) and in non-operated male Dark Agouti rats. Adrenalectomy aggravated the clinical course of experimental allergic encephalomyelitis. In contrast, propranolol attenuated both the clinical signs of the disease and decreased the number of lesions in the spinal cord. Furthermore, propranolol prevented adrenalectomy-induced aggravation of the disease course without affecting mortality. We also found that the percentage of CD4(+)CD25(+) T lymphocytes (recently activated or regulatory cells) was increased in peripheral blood of experimental allergic encephalomyelitis rats over that in the corresponding non-immunized and bovine serum albumin immunized rats. However, the percentage of these cells was reduced in adrenalectomized and/or propranolol-treated experimental allergic encephalomyelitis rats compared to control experimental allergic encephalomyelitis rats. Our findings, coupled with the clinical course of the disease and the underlying pathomorphological changes, clearly suggest that differential mechanisms were responsible for the changes in the percentage of CD4(+)CD25(+) T lymphocytes in propranolol-treated adrenalectomized rats and only propranolol-treated rats with experimental allergic encephalomyelitis. Our results, when viewed globally, indicate that: i) beta-adrenoceptor-dependent mechanisms are involved in the immunopathogenesis of experimental allergic encephalomyelitis, ii) experimental allergic encephalomyelitis has a more severe course in adrenalectomized rats and iii) beta-adrenoceptor-mediated mechanisms operate in adrenalectomy-induced aggravation of the disease.
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Affiliation(s)
- M Dimitrijević
- Immunology Research Centre Branislav Janković, Institute of Virology, Vaccines and Sera Torlak, 458 Vojvode Stepe, 11221 Belgrade, Serbia.
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Raivich G, Banati R. Brain microglia and blood-derived macrophages: molecular profiles and functional roles in multiple sclerosis and animal models of autoimmune demyelinating disease. ACTA ACUST UNITED AC 2005; 46:261-81. [PMID: 15571769 DOI: 10.1016/j.brainresrev.2004.06.006] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2004] [Indexed: 12/23/2022]
Abstract
Microglia and macrophages, one a brain-resident, the other a mostly hematogenous cell type, represent two related cell types involved in the brain pathology in multiple sclerosis and its autoimmune animal model, the experimental allergic encephalomyelitis. Together, they perform a variety of different functions: they are the primary sensors of brain pathology, they are rapidly recruited to sites of infection, trauma or autoimmune inflammation in experimental allergic encephalomyelitis and multiple sclerosis and they are competent presenters of antigen and interact with T cells recruited to the inflamed CNS. They also synthesise a variety of molecules, such as cytokines (TNF, interleukins), chemokines, accessory molecules (B7, CD40), complement, cell adhesion glycoproteins (integrins, selectins), reactive oxygen radicals and neurotrophins, that could exert a damaging or a protective effect on adjacent axons, myelin and oligodendrocytes. The current review will give a detailed summary on their cellular response, describe the different classes of molecules expressed and their attribution to the blood derived or brain-resident macrophages and then discuss how these molecules contribute to the neuropathology. Recent advances using chimaeric and genetically modified mice have been particularly telling about the specific, overlapping and nonoverlapping roles of macrophages and microglia in the demyelinating disease. Interestingly, they point to a crucial role of hematogenous macrophages in initiating inflammation and myelin removal, and that of microglia in checking excessive response and in the induction and maintenance of remission.
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Affiliation(s)
- Gennadij Raivich
- Department of Anatomy, Obstetrics and Gynaecology, Perinatal Brain Repair Centre, University College London, Chenies Mews 86-96 WC1E 6HX London, UK.
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16
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Raivich G, Banati R. Role of Microglia and Macrophages in Eae. Experimental Models of Multiple Sclerosis 2005. [DOI: 10.1007/0-387-25518-4_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Microglia and macrophages are related cell types that play an important role in the pathogenesis of MS and EAE. This chapters reviews the role of these cells in the normal brain and their contribution to inflammatory demyelinating disease, including their role in antigen presentation, co-stimulation, and production of cytokines and other inflammatory mediators
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17
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Chan A, Gold R. Apoptotic Cell Death in Experimental Autoimmune Encephalomyelitis. Experimental Models of Multiple Sclerosis 2005. [DOI: 10.1007/0-387-25518-4_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Particularly in the vulnerable CNS with a low capacity for regeneration specialized mechanisms must be active for the fast and gentle elimination of dysregulated autoaggressive immune cells. In EAE, local apoptosis of autoimmune T-cells has been identified as a safe means for the removal of these unwanted cells. T-cell apoptosis in situ followed by phagocytic clearance of apoptotic remnants by glia assures a minimum of detrimental bystander damage to the local parenchyma and down-regulates the local inflammatory reaction. The pharmacological augmentation of local apoptosis of inflammatory effector cells might gain therapeutic importance also in human neuroimmunological diseases such as multiple sclerosis.
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18
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Katychev A, Wang X, Duffy A, Dore-Duffy P. Glucocorticoid-induced apoptosis in CNS microvascular pericytes. Dev Neurosci 2004; 25:436-46. [PMID: 14966384 DOI: 10.1159/000075669] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2003] [Accepted: 10/20/2003] [Indexed: 11/19/2022] Open
Abstract
Pericyte loss or migration from its vascular location may be an important step in microvascular remodeling. Decreased pericyte to endothelial ratios are characteristics of newly formed vessels as well as microvessels undergoing regression, and may be due to selective degeneration via necrotic cell death or via programmed cell death. In this study, we have examined glucocorticoid-induced apoptosis in primary rat CNS pericytes. Characterization of apoptosis was determined using five independent criteria: (1) the translocation of receptors for annexin V from the inner to the outer surface of the plasma membrane, (2) the translocation of cytochrome C from the mitochondria to the cytosol, (3) the induction of DNA fragmentation, (4) the induction of classic changes in cell morphology, and (5) the appearance of TUNEL-positive cells. Incubation of CNS pericytes with dexamethasone induced the appearance of apoptotic cells in a time- and dose-dependent manner. Pericytes express immunologically detectable glucocorticoid receptors, and addition of the glucocorticoid receptor antagonist mifepristone inhibited dexamethasone-induced pericyte apoptosis. That pericytes undergo apoptosis in response to dexamethasone suggests that the regulatory function of this steroid may be important in vascular development and that pericyte apoptotic cell death may accompany vascular regression. Deregulation of pericyte involvement in vascular homeostasis and hemostasis may result in clinical disease.
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Affiliation(s)
- Andre Katychev
- Multiple Sclerosis Clinical Research Center, Department of Neurology, Division of Neuroimmunology, Wayne State University School of Medicine, Detroit Medical Center, Detroit, Mich. 48201, USA
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19
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Reddy S, Bradley J, Ginn S, Pathipati P, Ross JM. Immunohistochemical study of caspase-3-expressing cells within the pancreas of non-obese diabetic mice during cyclophosphamide-accelerated diabetes. Histochem Cell Biol 2003; 119:451-61. [PMID: 12802593 DOI: 10.1007/s00418-003-0537-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2003] [Indexed: 10/26/2022]
Abstract
During insulin-dependent diabetes mellitus, immune cells infiltrate pancreatic islets progressively and mediate beta cell destruction over a prolonged asymptomatic prediabetic period. Apoptosis may be a major mechanism of beta cell loss during the disease. This process involves a proteolytic cascade in which upstream procaspases are activated which themselves activate downstream caspases, including caspase-3, a key enzyme involved in the terminal apoptotic cascade. Here dual-label immunohistochemistry was employed to examine the intra-islet expression, distribution and cellular sources of active caspase-3 in the non-obese diabetic (NOD) mouse given cyclophosphamide to accelerate diabetes. NOD mice were treated at day 95 and caspase-3 expression was studied at days 0, 4, 7, 11 and 14. Its expression was also correlated with advancing disease and compared with age-matched NOD mice treated with diluent alone. At day 0 (=day 95), caspase-3 immunolabelling was observed in several peri-islet and intra-islet macrophages, but not in CD4 and CD8 cells and only extremely rarely in beta cells. At day 4, only a few beta cells weakly expressed the enzyme, in the absence of significant insulitis. At day 7, caspase-3 expression was observed in a small proportion of intra-islet macrophages. At day 11, there was a marked increase in the number of intra-islet macrophages positive for caspase-3 while only a few CD4 cells expressed the enzyme. At day 14, caspase-3 labelling became prominent in a significant proportion of macrophages. Only a few CD4 and CD8 cells expressed the enzyme. Capase-3 labelling was also present in a proportion of macrophages in perivascular and exocrine regions. Surprisingly, beta cell labelling of caspase-3 at days 11 and 14 was rare. At this stage of heightened beta cell loss, a proportion of intra-islet interleukin-1beta-positive cells coexpressed the enzyme. Caspase-3 was also observed in numerous Fas-positive cells in heavily infiltrated islets. During this late stage, only a proportion of caspase-3-positive cells contained apoptotic nuclei, as judged by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL). We conclude that during cyclophosphamide-accelerated diabetes in the NOD mouse, the predominant immunolabelling of caspase-3 in intra-islet macrophages suggests that apoptosis of macrophages may be an important mechanism for its elimination. The virtual absence of caspase-3 immunolabelling in most beta cells even during heightened beta cell loss supports their rapid clearance following their death during insulin-dependent diabetes mellitus.
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Affiliation(s)
- Shiva Reddy
- School of Biological Sciences and the Department of Paediatrics, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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20
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Abstract
Experimental autoimmune encephalomyelitis reproduces in rodents the features of multiple sclerosis, an immune-mediated, disabling disorder of the human nervous system. No adequate therapy is available for multiple sclerosis, despite anti-inflammatory, immunosuppressive, and immunomodulatory measures. Increasingly glutamate is implicated in the pathogenesis of neurodegenerative diseases. Here we (1) review changes in the glutamatergic system in multiple sclerosis and (2) reveal the effects of glutamate AMPA antagonists in acute and chronic rodent models of multiple sclerosis. Administration of structurally diverse competitive and non-competitive AMPA antagonists reduces neurologic disability in rodents subjected to acute experimental autoimmune encephalomyelitis. In addition, AMPA antagonists are active in both the adoptive transfer and in chronic models of experimental autoimmune encephalomyelitis in rats and mice and affect both the acute and chronic relapsing phases. Moreover, short-term therapy with AMPA antagonists leads to sustained benefit well into the progressive phases. These results imply that therapeutic strategies for multiple sclerosis should be complemented by glutamate AMPA antagonists to reduce neurologic disability.
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MESH Headings
- Animals
- Brain Stem/immunology
- Brain Stem/pathology
- Disease Models, Animal
- Encephalomyelitis, Autoimmune, Experimental/drug therapy
- Encephalomyelitis, Autoimmune, Experimental/etiology
- Encephalomyelitis, Autoimmune, Experimental/physiopathology
- Excitatory Amino Acid Antagonists/immunology
- Excitatory Amino Acid Antagonists/pharmacology
- Excitatory Amino Acid Antagonists/therapeutic use
- Glutamic Acid/metabolism
- Humans
- Mice
- Mice, Inbred Strains
- Multiple Sclerosis/drug therapy
- Multiple Sclerosis/etiology
- Multiple Sclerosis/physiopathology
- Nootropic Agents/pharmacology
- Nootropic Agents/therapeutic use
- Pyrrolidinones/pharmacology
- Pyrrolidinones/therapeutic use
- Quinoxalines/immunology
- Quinoxalines/pharmacology
- Quinoxalines/therapeutic use
- Rats
- Receptors, AMPA/antagonists & inhibitors
- Receptors, AMPA/metabolism
- Spinal Cord/immunology
- Spinal Cord/pathology
- Spinal Cord/ultrastructure
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Affiliation(s)
- Anthony J Groom
- Eisai London Research Laboratories, University College London, Bernard Katz Building, Gower Street, United Kingdom
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21
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Piraino PS, Yednock TA, Freedman SB, Messersmith EK, Pleiss MA, Vandevert C, Thorsett ED, Karlik SJ. Prolonged reversal of chronic experimental allergic encephalomyelitis using a small molecule inhibitor of alpha4 integrin. J Neuroimmunol 2002; 131:147-59. [PMID: 12458046 DOI: 10.1016/s0165-5728(02)00273-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
CNS leukocytic invasion in experimental allergic encephalomyelitis (EAE) depends on alpha4beta1 integrin/vascular cell adhesion molecule-1 (VCAM-1) interactions. A small molecule inhibitor of alpha4beta1 integrin (CT301) was administered to guinea pigs in the chronic phase (>d40) of EAE for 10, 20, 30 or 40 days. CT301 elicited a rapid, significant improvement in the clinical and pathological scores that was maintained throughout the treatment period. A progressive loss of cells in the spinal cord of treated animals confirmed the resolution of inflammation associated with clinical recovery. Therefore, prolonged inhibition of alpha4beta1 integrin caused a sustained reversal of disease pathology in chronic EAE and may be similarly useful in MS.
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Affiliation(s)
- P S Piraino
- Department of Physiology, London Health Sciences Center, University of Western Ontario, London, ON, Canada
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22
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Jones TB, Basso DM, Sodhi A, Pan JZ, Hart RP, MacCallum RC, Lee S, Whitacre CC, Popovich PG. Pathological CNS autoimmune disease triggered by traumatic spinal cord injury: implications for autoimmune vaccine therapy. J Neurosci 2002; 22:2690-700. [PMID: 11923434 DOI: 20026267] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Lymphocytes respond to myelin proteins after spinal cord injury (SCI) and may contribute to post-traumatic secondary degeneration. However, there is increasing evidence that autoreactive T-lymphocytes may also convey neuroprotection and promote functional recovery after CNS injury. To clarify the role of myelin autoreactive lymphocytes after SCI, we performed contusion injuries in the thoracic spinal cord of transgenic (Tg) mice in which >95% of all CD4+ T-lymphocytes are reactive with myelin basic protein (MBP). We observed significantly impaired recovery of locomotor and reflex function in Tg mice compared with non-Tg (nTg) littermates. Measures of functional impairment in Tg mice correlated with significantly less white matter at the injury site, and morphometric comparisons of injured Tg and nTg spinal cords revealed increased rostrocaudal lesion expansion (i.e., secondary degeneration) in Tg mice. Rostrocaudal to the impact site in SCI-nTg mice, demyelination was restricted to the dorsal funiculus, i.e., axons undergoing Wallerian degeneration. The remaining white matter appeared normal. In contrast, lymphocytes were colocalized with regions of demyelination and axon loss throughout the white matter of SCI-Tg mice. Impaired neurological function and exacerbated neuropathology in SCI-Tg mice were associated with increased intraspinal production of proinflammatory cytokine mRNA; neurotrophin mRNA was not elevated. These data suggest that endogenous MBP-reactive lymphocytes, activated by traumatic SCI, can contribute to tissue injury and impair functional recovery. Any neuroprotection afforded by myelin-reactive T-cells is likely to be an indirect effect mediated by other non-CNS-reactive lymphocytes. Similar to the Tg mice in this study, a subset of humans that are genetically predisposed to autoimmune diseases of the CNS may be adversely affected by vaccine therapies designed to boost autoreactive lymphocyte responses after CNS trauma. Consequently, the safe implementation of such therapies requires that future studies define the mechanisms that control T-cell function within the injured CNS.
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23
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Ciusani E, Gelati M, Frigerio S, Pollo B, Massa G, Sacerdote P, Panerai AE, Salmaggi A. Modulation of experimental allergic encephalomyelitis in Lewis rats by administration of a peptide of Fas ligand. J Autoimmun 2001; 17:273-80. [PMID: 11771951 DOI: 10.1006/jaut.2001.0554] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The effects of modulation of apoptosis in experimental allergic encephalomyelitis (EAE) in Lewis rats have been investigated using a peptide of the Fas-Ligand protein (FasL-p). The peptide was administered both subcutaneously and intra-cerebro-ventricularly (i.c.v.) after EAE induction. Rats treated subcutaneously with FasL-p showed a worse clinical score as compared to saline treated animals, while i.c.v. treatment with FasL-p did not modify significantly the severity of EAE. Apoptotic lymphomonocytes (identified by TUNEL) infiltrating the brain and the spinal cord were decreased in rats treated i.c.v. with FasL-p. The data suggest that the Fas/Fas-ligand pathway may be modulated by treatments with peptides of Fas-Ligand and that it may be at work within the central nervous system in EAE.
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Affiliation(s)
- E Ciusani
- Istituto Nazionale Neurologico 'C. Besta', Via Celoria 11, Milan, 20133, Italy
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24
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Abstract
Immune activity in general, and autoimmunity in particular, have long been considered as harmful in the context of central nervous system (CNS) trauma. Increasing evidence suggests, however, that the injured CNS can benefit from autoimmune manipulations. Active or passive immunization with CNS-associated self antigens was shown to promote recovery from a CNS insult. It is now also evident that this beneficial 'autoimmunity' is not solely an outcome of immune manipulation but is also a physiological response, evoked by a non-pathogenic insult and apparently designed to counteract the insult-related toxicity which is induced in part by essential physiological compounds present in excess of their normal levels. It appears that when the buffering capacity of constitutive local mechanisms (transporters, enzymes, etc.) that normally regulate these compounds is exceeded, assistance is recruited from the immune system. Like the overactive physiological compounds themselves, the immune system needs to be rigorously regulated in order to produce adequate phagocytic activity and the required quantity of cytokines and growth factors at the right time and place. Boosting of this autoimmune response is potentially a powerful strategy for neuroprotective therapy.
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Affiliation(s)
- M Schwartz
- Department of Neurobiology, The Weizmann Institute of Science, 76100, Rehovot, Israel.
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25
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Abstract
The elimination of inflammatory cells within the central nervous system (CNS) by apoptosis plays an important role in protecting the CNS from immune-mediated damage. T cells, B cells, macrophages, and microglia all undergo apoptosis in the CNS. The apoptotic elimination of CNS-reactive T cells is particularly important, as these cells can recruit and activate other inflammatory cells. T-cell apoptosis contributes to the resolution of CNS inflammation and clinical recovery from attacks of experimental autoimmune encephalomyelitis (EAE), an animal model of the demyelinating disease multiple sclerosis (MS). T-cell apoptosis in the CNS in EAE occurs in both an antigen-specific and an antigen-nonspecific manner. In antigen-specific T-cell apoptosis, it is proposed that T cells that recognize their antigen in the CNS, such as CNS-reactive T cells, are deleted by the process of activation-induced apoptosis after activation of the T-cell receptor. This may result from the ligation of T-cell death receptors (such as CD95 (Fas) or tumor necrosis factor (TNF) receptor 1) by CD95 ligand (CD95L) or TNF expressed by the same T cell or possibly by microglia, astrocytes or neurons. Inadequate costimulation of the T cell by antigen-presenting glial cells may render T cells susceptible to activation-induced apoptosis. T cells expressing CD95 may also die in an antigen-nonspecific manner after interacting with glial cells expressing CD95L. Other mechanisms for antigen-nonspecific T-cell apoptosis include the endogenous release of glucocorticosteroids, deprivation of interleukin-2, and the release of nitric oxide by macrophages or glia. Apoptosis of autoreactive T cells in the CNS is likely to be important in preventing the development of autoimmune CNS diseases such as MS.
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Affiliation(s)
- M P Pender
- Department of Medicine, University of Queensland, Brisbane, Australia
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26
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Marchetti B, Morale MC, Testa N, Tirolo C, Caniglia S, Amor S, Dijkstra CD, Barden N. Stress, the immune system and vulnerability to degenerative disorders of the central nervous system in transgenic mice expressing glucocorticoid receptor antisense RNA. Brain Res Brain Res Rev 2001; 37:259-72. [PMID: 11744091 DOI: 10.1016/s0165-0173(01)00130-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Current research evidence suggests that interactions between genetic and environmental factors contribute to modulate the susceptibility to degenerative disorders, including inflammatory and autoimmune diseases of the central nervous system (CNS). In this context, bidirectional communication between the neuroendocrine and immune systems during ontogeny plays a pivotal role in programming the development of neuroendocrine and immune responses in adult life, thereby influencing the predisposition to several disease entities. Glucocorticoids (GCs), the end products of the hypothalamic-pituitary-adrenocortical (HPA) axis, gender and signals generated by hypothalamic-pituitary-gonadal (HPG) axis are major players coordinating the development of immune system function and exerting powerful effects in the susceptibility to autoimmune disorders, including experimental autoimmune encephalomyelitis (EAE), the experimental model for multiple sclerosis (MS). In particular, GCs exert their beneficial immunosuppressive and anti-inflammatory effects in inflammatory disorders of the CNS, after binding to their cytoplasmic receptors (GRs). Here we review our work using transgenic (Tg) mice with a dysfunctional GR from early embryonic life on programming vulnerability to EAE. The GR-deficiency of these Tg mice confers resistance to active EAE induction. The interplay between GCs, proinflammatory mediators, gender and EAE is summarized. On the basis of our data, it does appear that exposure to a defective GR through development programs major changes in endogenous neuroendocrine and immune mechanisms controlling the vulnerability to EAE. These studies highlight the plasticity of the HPA-immune axis and its pharmacological manipulation in autoimmune diseases of the CNS.
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Affiliation(s)
- B Marchetti
- Department of Pharmacology, Medical School, University of Sassari 07100, Sassari, Italy.
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27
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Flügel A, Bradl M, Kreutzberg GW, Graeber MB. Transformation of donor-derived bone marrow precursors into host microglia during autoimmune CNS inflammation and during the retrograde response to axotomy. J Neurosci Res 2001; 66:74-82. [PMID: 11599003 DOI: 10.1002/jnr.1198] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Macrophages in the brain can have a triple source. They may originate from recently blood-derived precursors, from the largely resident perivascular cell population (perivascular macrophages and related cells), and from intrinsic parenchymal as well as perivascular microglia. Although continuous exchange of part of the perivascular cell population with bone marrow-derived precursors is now accepted, the turnover of adult parenchymal microglia has remained enigmatic. Using bone-marrow chimeras carrying an unexpressed marker gene and carbon labeling of peripheral monocyte/macrophages in a combined model of facial nerve axotomy and transfer experimental autoimmune encephalitis, we demonstrate for the first time that there is an easy to induce exchange between parenchymal central nervous system (CNS) microglia and the macrophage precursor cell pool of the bone marrow. Furthermore, very low level infiltration of the CNS parenchyma by recently bone marrow-derived microglia could be observed after simple peripheral nerve axotomy that is followed by neuronal regeneration. Thus, microglial cells can be considered wanderers between the peripheral immune system and the CNS where they may act as a "Trojan horse" in infections. The fact that recently bone marrow-derived parenchymal microglia fully integrate into a regenerating brain nucleus' architecture encourages entirely new approaches for delivering genes into the adult CNS.
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Affiliation(s)
- A Flügel
- Department of Neuroimmunology, Max-Planck-Institute of Neurobiology, Martinsried, Germany
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28
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Abstract
Glucocorticosteroids are the most potent immunosuppressive and antiinflammatory drugs. Over the six decades that have passed since their discovery, a variety of genomic effector mechanisms of steroid hormones has been described which are mediated by the cytosolic steroid receptor. Recent evidence supports a direct effect of glucocorticosteroids on cellular membranes that occurs at higher hormone concentrations, termed nongenomic effects. These imply a qualitatively distinct mode of steroid action leading to cellular apoptosis. In this review, we discuss in vitro and in vivo data on nongenomic effects of glucocorticosteroids and their possible implications for the therapy of human neuroimmunological diseases.
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Affiliation(s)
- R Gold
- Clinical Research Group for Multiple Sclerosis and Neuroimmunology, Department of Neurology, Julius Maximilians Universität Würzburg, Germany.
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29
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Kuhlmann T, Bitsch A, Stadelmann C, Siebert H, Brück W. Macrophages are eliminated from the injured peripheral nerve via local apoptosis and circulation to regional lymph nodes and the spleen. J Neurosci 2001; 21:3401-8. [PMID: 11331370 [PMID: 11331370 DOI: 10.1523/jneurosci.21-10-03401.2001] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The present study investigated the fate of macrophages in peripheral nerves undergoing Wallerian degeneration, especially their disappearance from the injured nerves after phagocytosis of axonal and myelin debris. Wallerian degeneration was induced in adult male C57Bl/6 mice by transecting the right sciatic nerve. Five days after transection, the male sciatic nerves were transplanted into female recipient mice by placing them exactly parallel to the host sciatic nerves. Nerves of the female recipient mice were also transected to induce breakdown of the blood-nerve barrier in the host animal. Apoptosis was assessed by morphological, immunohistochemical (activated caspase-3), and molecular (DNA fragmentation) methods in transplanted, recipient, and in control nerves. A subpopulation of macrophages within the degenerating nerves died locally by apoptosis in each experiment. The fate of the male macrophages within the transplanted nerves and the host organism was investigated by in situ hybridization with a Y-chromosome-specific DNA probe (145SC5). In situ hybridization specifically stained cells within the transplanted male nerve. Y-chromosome-positive cells were detected not only inside the transplanted nerve, but also inside the female host nerve, the perineurial tissue, the local perineurial blood vessels, draining lymph nodes and the spleen of the female host, suggesting hematogenous as well as lymphatic elimination of macrophages from the injured nerve. These data indicate that local apoptosis and systemic elimination via circulation to the local lymph nodes and the spleen are involved in the disappearance of macrophages from the injured peripheral nervous system.
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30
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Ahmed Z, Gveric D, Pryce G, Baker D, Leonard JP, Cuzner ML, Diemel LT. Myelin/axonal pathology in interleukin-12 induced serial relapses of experimental allergic encephalomyelitis in the Lewis rat. Am J Pathol 2001; 158:2127-38. [PMID: 11395390 PMCID: PMC1891982 DOI: 10.1016/s0002-9440(10)64684-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lewis rats, on recovery from monophasic clinical experimental allergic encephalomyelitis (EAE), can be induced to develop repeated paralytic relapses with a graded reduction in clinical severity following intraperitoneal administration of IL-12. By the time of the third relapse, the number and size of inflammatory cuffs in the spinal cord were reduced with the makeup of the cellular infiltrate shifting to a significantly increased number of B cells. Serum levels of myelin basic protein (MBP)-specific IgG1 and IgG2b were found to rise over time while MBP and MBP peptide-positive macrophages and microglia became evident in perivascular cuffs and in spinal cord parenchyma, indicative of myelin phagocytosis. Axonal death was observed in semithin and EM sections of spinal cord in third relapse animals in association with iNOS and tPA immunostaining throughout gray and white matter. These neurotoxic or excitotoxic agents may contribute to axonal damage directly or indirectly by activated microglia and macrophages, leading to limited damage of the axonal-myelin unit.
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Affiliation(s)
- Z Ahmed
- Neuroinflammation Group, Department of Neurochemistry, Institute of Neurology, University College London, London, United Kingdom.
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31
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Banati RB, Newcombe J, Gunn RN, Cagnin A, Turkheimer F, Heppner F, Price G, Wegner F, Giovannoni G, Miller DH, Perkin GD, Smith T, Hewson AK, Bydder G, Kreutzberg GW, Jones T, Cuzner ML, Myers R. The peripheral benzodiazepine binding site in the brain in multiple sclerosis: quantitative in vivo imaging of microglia as a measure of disease activity. Brain 2000; 123 ( Pt 11):2321-37. [PMID: 11050032 DOI: 10.1093/brain/123.11.2321] [Citation(s) in RCA: 510] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
This study identifies by microautoradiography activated microglia/macrophages as the main cell type expressing the peripheral benzodiazepine binding site (PBBS) at sites of active CNS pathology. Quantitative measurements of PBBS expression in vivo obtained by PET and [(11)C](R)-PK11195 are shown to correspond to animal experimental and human post-mortem data on the distribution pattern of activated microglia in inflammatory brain disease. Film autoradiography with [(3)H](R)-PK11195, a specific ligand for the PBBS, showed minimal binding in normal control CNS, whereas maximal binding to mononuclear cells was found in multiple sclerosis plaques. However, there was also significantly increased [(3)H](R)-PK11195 binding on activated microglia outside the histopathologically defined borders of multiple sclerosis plaques and in areas, such as the cerebral central grey matter, that are not normally reported as sites of pathology in multiple sclerosis. A similar pattern of [(3)H](R)-PK11195 binding in areas containing activated microglia was seen in the CNS of animals with experimental allergic encephalomyelitis (EAE). In areas without identifiable focal pathology, immunocytochemical staining combined with high-resolution emulsion autoradiography demonstrated that the cellular source of [(3)H](R)-PK11195 binding is activated microglia, which frequently retains a ramified morphology. Furthermore, in vitro radioligand binding studies confirmed that microglial activation leads to a rise in the number of PBBS and not a change in binding affinity. Quantitative [(11)C](R)-PK11195 PET in multiple sclerosis patients demonstrated increased PBBS expression in areas of focal pathology identified by T(1)- and T(2)-weighted MRI and, importantly, also in normal-appearing anatomical structures, including cerebral central grey matter. The additional binding frequently delineated neuronal projection areas, such as the lateral geniculate bodies in patients with a history of optic neuritis. In summary, [(11)C](R)-PK11195 PET provides a cellular marker of disease activity in vivo in the human brain.
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Affiliation(s)
- R B Banati
- MRC Cyclotron Unit and Robert Steiner Magnetic Resonance Imaging Unit, Imperial College School of Medicine, Hammersmith Hospital, London, United Kingdom
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32
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Abstract
The homeostasis of the immune system is maintained by apoptotic (programmed cell death) elimination of potentially pathogenic, autoreactive mononuclear cells. There is emerging evidence that apoptosis mediated by the cell death receptor Fas is impaired in activated lymphocytes from patients with multiple sclerosis (MS), but other forms of apoptosis have not yet been fully evaluated. To further explore the dynamics of programmed cell death in MS, spontaneous and induced apoptosis of both peripheral and intrathecal mononuclear cells was investigated in clinically active MS patients and appropriate controls. In the MS group, spontaneous apoptosis of unfractionated mononuclear cells was significantly reduced, and activated intrathecal and peripheral T cells were found to be predominantly resistant to Fas-independent apoptosis. These results indicate that in clinically active MS, the reduced susceptibility of mononuclear cells to apoptosis is partly due to impairment of Fas-independent apoptotic pathways.
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Affiliation(s)
- M K Sharief
- Department of Neurology, Guy's, King's and St. Thomas's, School of Medicine, Guy's Hospital, Hodgkin Building, SE1 9RT, London, UK.
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33
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Abstract
Experimental autoimmune encephalomyelitis (EAE) is a T-cell-mediated disorder characterized by infiltration of the central nervous system (CNS) by mononuclear cells and macrophages, and serves as a model for multiple sclerosis. In acute monophasic and relapsing remitting forms of EAE, the CNS inflammatory infiltrates are cleared within a few days and, simultaneously, animals recover from their clinical disability. The mechanisms for rapid disappearance of the inflammatory cells are not fully understood. Fas and Fas-ligand (Fas-L) molecules are thought to play an important role in the deletion of autoimmune reactive T cells through apoptosis. However, recent observations in transgenic lpr and gld mice show that mutations inactivating Fas and Fas-L respectively ameliorate signs of EAE despite persistence of immune cell infiltrates into the CNS. In the current study, the expression of Fas and Fas-L was investigated by immunochemistry and in situ hybridization during the course of EAE in DA rats that were actively immunized with syngenic spinal cord homogenate. CNS apoptotic cells were simultaneously examined using terminal transferase dUTP nick end-labeling techniques. During the acute phase of the disease, a significant proportion of CNS CD4+ cells (80%) and macrophages (50%) expressed Fas and Fas-L (80 and 60%, respectively). Simultaneously, about 20% of CD4+ cells and 30% of macrophages were found to be apoptotic. Some astrocytes and neurons also expressed Fas and Fas-L, although they did not appear to be apoptotic. These results further support a role for Fas-mediated lymphocyte and macrophage apoptosis in this model of CNS autoimmune disease but they also suggest a more complex role for Fas/Fas-L interactions in CNS autoimmunity, including resident cells.
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Affiliation(s)
- J Ouallet
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unit 495, Hôpital de la Salpêtrière, Paris, France.
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34
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Moalem G, Monsonego A, Shani Y, Cohen IR, Schwartz M. Differential T cell response in central and peripheral nerve injury: connection with immune privilege. FASEB J 1999; 13:1207-17. [PMID: 10385611 DOI: 10.1096/fasebj.13.10.1207] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The central nervous system (CNS), unlike the peripheral nervous system (PNS), is an immune-privileged site in which local immune responses are restricted. Whereas immune privilege in the intact CNS has been studied intensively, little is known about its effects after trauma. In this study, we examined the influence of CNS immune privilege on T cell response to central nerve injury. Immunocytochemistry revealed a significantly greater accumulation of endogenous T cells in the injured rat sciatic nerve than in the injured rat optic nerve (representing PNS and CNS white matter trauma, respectively). Use of the in situ terminal deoxytransferase-catalyzed DNA nick end labeling (TUNEL) procedure revealed extensive death of accumulating T cells in injured CNS nerves as well as in CNS nerves of rats with acute experimental autoimmune encephalomyelitis, but not in injured PNS nerves. Although Fas ligand (FasL) protein was expressed in white matter tissue of both systems, it was more pronounced in the CNS. Expression of major histocompatibility complex (MHC) class II antigens was found to be constitutive in the PNS, but in the CNS was induced only after injury. Our findings suggest that the T cell response to central nerve injury is restricted by the reduced expression of MHC class II antigens, the pronounced FasL expression, and the elimination of infiltrating lymphocytes through cell death.
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Affiliation(s)
- G Moalem
- Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel Department of Immunology, The Weizmann Institute of Science, 76100 Rehovot, Israel
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35
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Abstract
Normal individuals have mature T lymphocytes that are capable of reacting to self-antigens and can be activated by cross-reacting environmental antigens. The mechanism that maintains immune tolerance and prevents these activated autoreactive T cells from causing autoimmune disease is unclear. We have previously hypothesized that activation-induced apoptosis of previously activated autoreactive T cells in the target organ is a major mechanism for maintaining tolerance. Here I review the current evidence to support this hypothesis. It is proposed that when activated autoreactive T cells enter the target organ, they are reactivated mainly by non-professional antigen-presenting cells (APC) and deleted by activation-induced apoptosis through the Fas (CD95) pathway before producing significant target organ damage. This apoptosis occurs because the reactivated T cells do not receive sufficient costimulation from the non-professional APC to up-regulate their expression of Bcl-2-related anti-apoptotic proteins, which inhibit the CD95 pro-apoptotic pathway. This is in contrast to the situation in peripheral lymphoid organs, where reactivation of T cells by professional APC results in sufficient costimulation-induced up-regulation of Bcl-2-related proteins to inhibit the CD95 pathway and allow T cell proliferation and survival as memory T cells. Activation-induced apoptosis of alloreactive T cells in allografts can similarly account for spontaneous allograft acceptance, as occurs after MHC-mismatched liver transplantation.
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Affiliation(s)
- M P Pender
- Department of Medicine, The University of Queensland, Brisbane, Queensland, Australia.
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Bauer J, Bradl M, Hickley WF, Forss-Petter S, Breitschopf H, Linington C, Wekerle H, Lassmann H. T-cell apoptosis in inflammatory brain lesions: destruction of T cells does not depend on antigen recognition. Am J Pathol 1998; 153:715-24. [PMID: 9736022 PMCID: PMC1853020 DOI: 10.1016/s0002-9440(10)65615-5] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Elimination of inflammatory T cells by apoptosis appears to play an important role in the down-regulation of inflammation in the central nervous system. Here we report that apoptosis of T lymphocytes occurs to a similar extent in different models of autoimmune encephalomyelitis. Apoptosis is restricted to cells located in the neuroectodermal parenchyma, thereby leaving T cells present in the brain's connective tissue compartments unharmed. Death of T cells in the parenchyma does not depend on antigen presentation by resident microglial cells or astrocytes. Adoptive transfer experiments with T lymphocytes carrying a specific genetic marker revealed that in the central nervous system these cells are destroyed regardless of their antigen specificity or state of activation. Although many of both antigen-dependent and -independent mechanisms in the induction of T-cell apoptosis may act simultaneously, our results suggest that the nervous system harbors a specific, currently undefined, mechanism that effectively eliminates infiltrating T lymphocytes.
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Affiliation(s)
- J Bauer
- Institute of Neurology, University of Vienna, Austria
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37
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Abstract
Combining in situ tailing and immunocytochemical staining, we demonstrated that the infiltrating macrophages in muscle tissue sections during early phase of experimental autoimmune myasthenia gravis (EAMG) in Lewis rats were eliminated by apoptosis at high frequency. These apoptotic macrophages were colocalized in the end-plate regions. Apoptosis is a major cause for elimination of infiltrating macrophages during the early phase of EAMG.
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Affiliation(s)
- F D Shi
- Division of Neurology, Karolinska Institute, Huddinge University Hospital, Stockholm, Sweden.
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38
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Abstract
Multiple sclerosis (MS) is a chromatic inflammatory disease of the central nervous system. T lymphocytes play a major role in the pathogenesis of the disease. The exact mechanisms by which the inflammation is regulated in MS have not yet been defined. Studies in animal models of MS suggest that apoptosis of T cells is the main factor terminating inflammation. The process of apoptosis itself is regulated by a range of pro- and anti-apoptotic proteins. The bcl-2 gene family is an important member of these proteins. The present study investigated the expression of the anti-apoptotic protein bcl-2 in 11 chronic MS cases including five relapsing-remitting and six chronic progressive MS patients. A total of 35 lesions containing all stages of demyelinating activity were studied. The number of CD 3-positive T cells and the absolute and relative numbers of T cells expressing bcl-2 were determined by double immunocytochemistry. Bcl-2 is expressed by T lymphocytes in MS plaques. Patients with chronic progressive MS have a higher proportion of bcl-2 expressing T cells than patients with relapsing remitting disease. Highest numbers of bcl-2-positive T lymphocytes were found in remyelinating and demyelinated lesions, whereas active demyelinating lesions revealed lower numbers. These data indicate that cell-death-related proteins such as the anti-apoptotic protein bcl-2 are expressed in MS lesions and that they might have important effects on the regulation of elimination or persistence of inflammatory cells in the central nervous system.
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Affiliation(s)
- U K Zettl
- Department of Neurology, University of Rostock, Germany
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39
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Abstract
Experimental allergic encephalomyelitis (EAE), an animal model for multiple sclerosis (MS), is a demyelinating autoimmune disease of the central nervous system (CNS). The proinflammatory cytokine TNF alpha, as an endogenous mediator of inflammation, plays an important role in the pathogenesis of EAE disease. In this study, we demonstrate the presence of TNF alpha in spinal cord of Lewis rats, during the critical phase of EAE. The expression of TNF alpha is observed mainly in the gray matter of thoracic and lumbar levels of the spinal cord, in the motoneurons and interneurons of the ventral horn. Surprisingly, one month after recovery, we still found an intense TNF alpha-neuronal expression, including in the cervical region, and this positivity lasted up to 40 days after recovery, with, however, a decrease in its intensity. These results suggest that central neurons respond directly to massive infiltration of lymphocytes and macrophages after the breakdown of the blood-brain barrier (BBB), by producing TNF alpha cytokine. In addition, neuronal-TNF alpha detection in the recovery stage of EAE may suggest a role other than its classical action in promoting inflammatory processes.
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Affiliation(s)
- H Villarroya
- INSERM U 134, Hôpital de la Salpêtrière, Paris, France
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40
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Gold R, Hartung HP, Lassmann H. T-cell apoptosis in autoimmune diseases: termination of inflammation in the nervous system and other sites with specialized immune-defense mechanisms. Trends Neurosci 1997; 20:399-404. [PMID: 9292968 PMCID: PMC7127798 DOI: 10.1016/s0166-2236(97)01079-5] [Citation(s) in RCA: 125] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have studied T-cell apoptosis in animal models of human autoimmune disorders of the nervous system and in other tissues devoid of specialized immune-defense mechanisms. Our data suggest that the CNS has high potential for elimination of T-cell-dependent inflammation, whereas this mechanism is less effective in the PNS, and is almost absent in other tissues such as muscle and skin. Interestingly, several conventional and novel immunotherapeutic approaches, such as glucocorticosteroid and high-dose antigen therapy, induce T-cell apoptosis in situ. In vitro experiments suggest different scenarios for the mechanisms by which specific cellular and humoral elements in the nervous system synergize and sensitize T cells for apoptosis in vivo. We also discuss regulatory, proapoptotic mechanisms, such as the Fas-FasL system and galectin-I, that have been utilized in other tissues to mediate immune protection.
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Affiliation(s)
- R Gold
- Dept of Neurology, Clinical Research Unit for Multiple Sclerosis, Würzburg, Germany
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