TY - JOUR A1 - Vogelsang, Anna A1 - Eichler, Susann A1 - Huntemann, Niklas A1 - Masanneck, Lars A1 - Böhnlein, Hannes A1 - Schüngel, Lisa A1 - Willison, Alice A1 - Loser, Karin A1 - Nieswandt, Bernhard A1 - Kehrel, Beate E. A1 - Zarbock, Alexander A1 - Göbel, Kerstin A1 - Meuth, Sven G. T1 - Platelet inhibition by low-dose acetylsalicylic acid reduces neuroinflammation in an animal model of multiple sclerosis JF - International Journal of Molecular Sciences N2 - Aside from the established immune-mediated etiology of multiple sclerosis (MS), compelling evidence implicates platelets as important players in disease pathogenesis. Specifically, numerous studies have highlighted that activated platelets promote the central nervous system (CNS)-directed adaptive immune response early in the disease course. Platelets, therefore, present a novel opportunity for modulating the neuroinflammatory process that characterizes MS. We hypothesized that the well-known antiplatelet agent acetylsalicylic acid (ASA) could inhibit neuroinflammation by affecting platelets if applied at low-dose and investigated its effect during experimental autoimmune encephalomyelitis (EAE) as a model to study MS. We found that oral administration of low-dose ASA alleviates symptoms of EAE accompanied by reduced inflammatory infiltrates and less extensive demyelination. Remarkably, the percentage of CNS-infiltrated CD4\(^+\) T cells, the major drivers of neuroinflammation, was decreased to 40.98 ± 3.28% in ASA-treated mice compared to 56.11 ± 1.46% in control animals at the disease maximum as revealed by flow cytometry. More interestingly, plasma levels of thromboxane A\(_2\) were decreased, while concentrations of platelet factor 4 and glycoprotein VI were not affected by low-dose ASA treatment. Overall, we demonstrate that low-dose ASA could ameliorate the platelet-dependent neuroinflammatory response in vivo, thus indicating a potential treatment approach for MS. KW - acetylsalicylic acid KW - experimental autoimmune encephalomyelitis KW - platelets KW - multiple sclerosis KW - thromboxane KW - glycoprotein VI KW - platelet factor 4 Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-284535 SN - 1422-0067 VL - 22 IS - 18 ER - TY - JOUR A1 - Koeniger, Tobias A1 - Kuerten, Stefanie T1 - Splitting the "unsplittable": Dissecting resident and infiltrating macrophages in experimental autoimmune encephalomyelitis JF - International Journal of Molecular Sciences N2 - Macrophages predominate the inflammatory landscape within multiple sclerosis (MS) lesions, not only regarding cellularity but also with respect to the diverse functions this cell fraction provides during disease progression and remission. Researchers have been well aware of the fact that the macrophage pool during central nervous system (CNS) autoimmunity consists of a mixture of myeloid cells. Yet, separating these populations to define their unique contribution to disease pathology has long been challenging due to their similar marker expression. Sophisticated lineage tracing approaches as well as comprehensive transcriptome analysis have elevated our insight into macrophage biology to a new level enabling scientists to dissect the roles of resident (microglia and non-parenchymal macrophages) and infiltrating macrophages with unprecedented precision. To do so in an accurate way, researchers have to know their toolbox, which has been filled with diverse, discriminating approaches from decades of studying neuroinflammation in animal models. Every method has its own strengths and weaknesses, which will be addressed in this review. The focus will be on tools to manipulate and/or identify different macrophage subgroups within the injured murine CNS. KW - CNS KW - distinction KW - experimental autoimmune encephalomyelitis KW - inflammation KW - macrophages KW - markers KW - microglia KW - monocytes Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-285067 SN - 1422-0067 VL - 18 IS - 10 ER - TY - JOUR A1 - Kamali, Salar A1 - Rajendran, Ranjithkumar A1 - Stadelmann, Christine A1 - Karnati, Srikanth A1 - Rajendran, Vinothkumar A1 - Giraldo‐Velasquez, Mario A1 - Berghoff, Martin T1 - Oligodendrocyte‐specific deletion of FGFR2 ameliorates MOG\(_{35-55}\)‐induced EAE through ERK and Akt signalling JF - Brain Pathology N2 - Fibroblast growth factors (FGFs) and their receptors (FGFRs) are involved in demyelinating pathologies including multiple sclerosis (MS). In our recent study, oligodendrocyte‐specific deletion of FGFR1 resulted in a milder disease course, less inflammation, reduced myelin and axon damage in EAE. The objective of this study was to elucidate the role of oligodendroglial FGFR2 in MOG\(_{35-55}\)‐induced EAE. Oligodendrocyte‐specific knockout of FGFR2 (Fgfr2\(^{ind-/-}\)) was achieved by application of tamoxifen; EAE was induced using the MOG\(_{35-55}\) peptide. EAE symptoms were monitored over 62 days. Spinal cord tissue was analysed by histology, immunohistochemistry and western blot. Fgfr2\(^{ind-/-}\) mice revealed a milder disease course, less myelin damage and enhanced axonal density. The number of oligodendrocytes was not affected in demyelinated areas. However, protein expression of FGFR2, FGF2 and FGF9 was downregulated in Fgfr2\(^{ind-/-}\) mice. FGF/FGFR dependent signalling proteins were differentially regulated; pAkt was upregulated and pERK was downregulated in Fgfr2\(^{ind-/-}\) mice. The number of CD3(+) T cells, Mac3(+) cells and B220(+) B cells was less in demyelinated lesions of Fgfr2\(^{ind-/-}\) mice. Furthermore, expression of IL‐1β, TNF‐α and CD200 was less in Fgfr2\(^{ind-/-}\) mice than controls. Fgfr2ind−/− mice showed an upregulation of PLP and downregulation of the remyelination inhibitors SEMA3A and TGF‐β expression. These data suggest that cell‐specific deletion of FGFR2 in oligodendrocytes has anti‐inflammatory and neuroprotective effects accompanied by changes in FGF/FGFR dependent signalling, inflammatory cytokines and expression of remyelination inhibitors. Thus, FGFRs in oligodendrocytes may represent potential targets for the treatment of inflammatory and demyelinating diseases including MS. KW - experimental autoimmune encephalomyelitis KW - FGF/FGFR signalling KW - multiple sclerosis KW - oligodendrocytes Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224354 VL - 31 SP - 297 EP - 311 ER - TY - JOUR A1 - Rottlaender, Andrea A1 - Kuerten, Stefanie T1 - Stepchild or prodigy? Neuroprotection in multiple sclerosis (MS) research JF - International Journal of Molecular Sciences N2 - Multiple sclerosis (MS) is an autoimmune disorder of the central nervous system (CNS) and characterized by the infiltration of immune cells, demyelination and axonal loss. Loss of axons and nerve fiber pathology are widely accepted as correlates of neurological disability. Hence, it is surprising that the development of neuroprotective therapies has been neglected for a long time. A reason for this could be the diversity of the underlying mechanisms, complex changes in nerve fiber pathology and the absence of biomarkers and tools to quantify neuroregenerative processes. Present therapeutic strategies are aimed at modulating or suppressing the immune response, but do not primarily attenuate axonal pathology. Yet, target-oriented neuroprotective strategies are essential for the treatment of MS, especially as severe damage of nerve fibers mostly occurs in the course of disease progression and cannot be impeded by immune modulatory drugs. This review shall depict the need for neuroprotective strategies and elucidate difficulties and opportunities. KW - experimental autoimmune encephalomyelitis KW - white matter KW - lesions KW - remyelination KW - multiple sclerosis KW - regeneration KW - neuroprotection KW - degeneration KW - axonal damage KW - neurodegeneration KW - pathology KW - sodium channels KW - axonal injury KW - central nervous system Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148416 VL - 16 ER - TY - JOUR A1 - Schuhmann, Michael K. A1 - Bittner, Stefan A1 - Meuth, Sven G. A1 - Kleinschnitz, Christoph A1 - Fluri, Felix T1 - Fingolimod (FTY720-P) does not stabilize the blood-brain barrier under inflammatory conditions in an in vitro model JF - International Journal of Molecular Sciences N2 - Breakdown of the blood-brain barrier (BBB) is an early hallmark of multiple sclerosis (MS), a progressive inflammatory disease of the central nervous system. Cell adhesion in the BBB is modulated by sphingosine-1-phosphate (S1P), a signaling protein, via S1P receptors (S1P\(_1\)). Fingolimod phosphate (FTY720-P) a functional S1P\(_1\) antagonist has been shown to improve the relapse rate in relapsing-remitting MS by preventing the egress of lymphocytes from lymph nodes. However, its role in modulating BBB permeabilityin particular, on the tight junction proteins occludin, claudin 5 and ZO-1has not been well elucidated to date. In the present study, FTY720-P did not change the transendothelial electrical resistance in a rat brain microvascular endothelial cell (RBMEC) culture exposed to inflammatory conditions and thus did not decrease endothelial barrier permeability. In contrast, occludin was reduced in RBMEC culture after adding FTY720-P. Additionally, FTY720-P did not alter the amount of endothelial matrix metalloproteinase (MMP)-9 and MMP-2 in RBMEC cultures. Taken together, our observations support the assumption that S1P\(_1\) plays a dual role in vascular permeability, depending on its ligand. Thus, S1P\(_1\) provides a mechanistic basis for FTY720-P-associated disruption of endothelial barrierssuch as the blood-retinal barrierwhich might result in macular edema. KW - randomized controlled trial KW - Sphingosine 1-Phosphate KW - vascular permeability KW - rat brain microvascular endothelial cell culture KW - tight junctions KW - FTY720-P KW - blood-brain barrier KW - inflammation KW - novo renal transplantation KW - endothelial cells KW - experimental autoimmune encephalomyelitis KW - relapsing multiple sclerosis KW - Zonula Occludens-1 KW - matrix metalloproteinases Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-145047 VL - 16 ER - TY - JOUR A1 - Ip, Chi Wang A1 - Kroner, Antje A1 - Groh, Janos A1 - Huber, Marianne A1 - Klein, Dennis A1 - Spahn, Irene A1 - Diem, Ricarda A1 - Williams, Sarah K. A1 - Nave, Klaus-Armin A1 - Edgar, Julia M. A1 - Martini, Rudolf T1 - Neuroinflammation by Cytotoxic T-Lymphocytes Impairs Retrograde Axonal Transport in an Oligodendrocyte Mutant Mouse JF - PLoS One N2 - Mice overexpressing proteolipid protein (PLP) develop a leukodystrophy-like disease involving cytotoxic, CD8+ T-lymphocytes. Here we show that these cytotoxic T-lymphocytes perturb retrograde axonal transport. Using fluorogold stereotactically injected into the colliculus superior, we found that PLP overexpression in oligodendrocytes led to significantly reduced retrograde axonal transport in retina ganglion cell axons. We also observed an accumulation of mitochondria in the juxtaparanodal axonal swellings, indicative for a disturbed axonal transport. PLP overexpression in the absence of T-lymphocytes rescued retrograde axonal transport defects and abolished axonal swellings. Bone marrow transfer from wildtype mice, but not from perforin- or granzyme B-deficient mutants, into lymphocyte-deficient PLP mutant mice led again to impaired axonal transport and the formation of axonal swellings, which are predominantly located at the juxtaparanodal region. This demonstrates that the adaptive immune system, including cytotoxic T-lymphocytes which release perforin and granzyme B, are necessary to perturb axonal integrity in the PLP-transgenic disease model. Based on our observations, so far not attended molecular and cellular players belonging to the immune system should be considered to understand pathogenesis in inherited myelin disorders with progressive axonal damage. KW - myelin KW - experimental autoimmune encephalomyelitis KW - degeneration KW - axonopathic changes KW - neural apoptosis KW - nervous system KW - motor function KW - proteolipid protein gene KW - retinal ganglion cells KW - granzyme B KW - multiple sclerosis Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-134982 VL - 7 IS - 8 ER - TY - THES A1 - Schampel, Andrea T1 - Beneficial therapeutic effects of the L-type calcium channel antagonist nimodipine in experimental autoimmune encephalomyelitis – an animal model for multiple sclerosis T1 - Günstige therapeutische Effekte des L-Typ-Calciumkanal-Antagonisten Nimodipin in der experimentellen autoimmunen Enzephalomyelitis ̶ einem Tiermodell der Multiplen Sklerose N2 - Multiple sclerosis (MS) is the most prevalent neurological disease of the central nervous system (CNS) in young adults and is characterized by inflammation, demyelination and axonal pathology that result in multiple neurological and cognitive deficits. The focus of MS research remains on modulating the immune response, but common therapeutic strategies are only effective in slowing down disease progression and attenuating the symptoms; they cannot cure the disease. Developing an option to prevent neurodegeneration early on would be a valuable addition to the current standard of care for MS. Based on our results we suggest that application of nimodipine could be an effective way to target both neuroinflammation and neurodegeneration. We performed detailed analyses of neurodegeneration in experimental autoimmune encephalomyelitis (EAE), an animal model of MS, and in in vitro experiments regarding the effect of the clinically well-established L-type calcium channel antagonist nimodipine. Nimodipine treatment attenuated the course of EAE and spinal cord histopathology. Furthermore, it promoted remyelination. The latter could be due to the protective effect on oligodendrocytes and oligodendrocyte precursor cells (OPCs) we observed in response to nimodipine treatment. To our surprise, we detected calcium channel-independent effects on microglia, resulting in apoptosis. These effects were cell type-specific and independent of microglia polarization. Apoptosis was accompanied by decreased levels of nitric oxide (NO) and inducible NO synthase (iNOS) in cell culture as well as decreased iNOS expression and reactive oxygen species (ROS) activity in EAE. Overall, application of nimodipine seems to generate a favorable environment for regenerative processes and could therefore be a novel treatment option for MS, combining immunomodulatory effects while promoting neuroregeneration. N2 - Multiple Sklerose (MS) ist die häufigste neurologische Erkrankung des zentralen Nervensystems (ZNS) von jungen Erwachsenen und charakterisiert durch Inflammation, Demyelinisierung und axonale Pathologie. Diese Prozesse bewirken zahlreiche neurologische und kognitive Defizite. Der Schwerpunkt in der MS-Forschung besteht derzeit vor allem in der Modulation der Immunantwort, jedoch sind herkömmliche Therapiestrategien bislang nur in der Lage die Progression der Erkrankung zu verlangsamen und die Symptome zu lindern, die Krankheit kann jedoch immer noch nicht geheilt werden. Die Möglichkeit, den Prozess der Neurodegeneration früh aufzuhalten, würde eine wertvolle Ergänzung zu herkömmlichen Therapien darstellen. Basierend auf den Ergebnissen dieser Studie schlagen wir vor, dass die Applikation von Nimodipin eine elegante Möglichkeit wäre, um sowohl die Neuroinflammation als auch die -degeneration zu bekämpfen. Um den Effekt des klinisch gut etablierten Calciumkanal-Antagonisten Nimodipin zu untersuchen, haben wir detaillierte Analysen der Degeneration in der experimentellen autoimmunen Enzephalomyelitis (EAE), einem Tiermodell der MS, und in in vitro Untersuchungen durchgeführt. Applikation von Nimodipin verringerte das klinische Erscheinungsbild der EAE sowie die Histopathologie des Rückenmarkes. Außerdem förderte es die Regeneration. Die Ursache für letzteres liegt vermutlich am protektiven Effekt der Behandlung mit Nimodipin auf die Oligodendrozyten und deren Vorläuferzellen. Überraschenderweise, konnten wir Calciumkanal-unspezifische Effekte auf Mikroglia feststellen, die in Apoptose resultierten und sowohl Zelltyp-spezifisch als auch unabhängig von der Polarisierung der Mikrogliazellen waren. Apoptose wurde begleitet von reduzierten Spiegeln an Stickstoffmonoxid (NO) und der induzierbaren NO Synthase (iNOS) in Zellkultur, sowie einer reduzierten Expression von iNOS und dem geringeren Vorkommen von reaktiven oxygenen Spezies (ROS) in der EAE. Zusammenfassend gehen wir davon aus, dass die Applikation von Nimodipin eine günstige Umgebung für regenerative Prozesse schafft. Daher stellt die Applikation dieser Substanz eine neue Behandlungsmöglichkeit für die MS dar, insbesondere da sie Möglichkeiten der Immunmodulation mit der Förderung von Neuroregeneration verbindet. KW - Nimodipin KW - Multiple Sklerose KW - l-type calcium channel antagonist KW - experimental autoimmune encephalomyelitis KW - L-typ Calciumkanal Antagonist KW - experimentelle autoimmune Enzephalomyelitis KW - neuroprotection KW - multiple sclerosis Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148952 ER - TY - JOUR A1 - Schrewe, L. A1 - Lill, C. M. A1 - Liu, T. A1 - Salmen, A. A1 - Gerdes, L. A. A1 - Guillot-Noel, L. A1 - Akkad, D. A. A1 - Blaschke, P. A1 - Graetz, C. A1 - Hoffjan, S. A1 - Kroner, A. A1 - Demir, S. A1 - Böhme, A. A1 - Rieckmann, P. A1 - El Ali, A. A1 - Hagemann, N. A1 - Hermann, D. M. A1 - Cournu-Rebeix, I. A1 - Zipp, F. A1 - Kümpfel, T. A1 - Buttmann, M. A1 - Zettl, U. K. A1 - Fontaine, B. A1 - Bertram, L. A1 - Gold, R. A1 - Chan, A. T1 - Investigation of sex-specific effects of apolipoprotein E on severity of EAE and MS JF - Journal of Neuroinflammation N2 - Background: Despite pleiotropic immunomodulatory effects of apolipoprotein E (apoE) in vitro, its effects on the clinical course of experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS) are still controversial. As sex hormones modify immunomodulatory apoE functions, they may explain contentious findings. This study aimed to investigate sex-specific effects of apoE on disease course of EAE and MS. Methods: MOG\(_{35-55}\) induced EAE in female and male apoE-deficient mice was assessed clinically and histopathologically. apoE expression was investigated by qPCR. The association of the MS severity score (MSSS) and APOE rs429358 and rs7412 was assessed across 3237 MS patients using linear regression analyses. Results: EAE disease course was slightly attenuated in male apoE-deficient (apoE\(^{-/-}\)) mice compared to wildtype mice (cumulative median score: apoE\(^{-/-}\) = 2 [IQR 0.0-4.5]; wildtype = 4 [IQR 1.0-5.0]; n = 10 each group, p = 0.0002). In contrast, EAE was more severe in female apoE\(^{-/-}\) mice compared to wildtype mice (cumulative median score: apoE\(^{-/-}\) = 3 [IQR 2.0-4.5]; wildtype = 3 [IQR 0.0-4.0]; n = 10, p = 0.003). In wildtype animals, apoE expression during the chronic EAE phase was increased in both females and males (in comparison to naive animals; p < 0.001). However, in MS, we did not observe a significant association between MSSS and rs429358 or rs7412, neither in the overall analyses nor upon stratification for sex. Conclusions: apoE exerts moderate sex-specific effects on EAE severity. However, the results in the apoE knock-out model are not comparable to effects of polymorphic variants in the human APOE gene, thus pinpointing the challenge of translating findings from the EAE model to the human disease. KW - immune KW - apoE KW - gender KW - inflammation KW - association studies in genetics KW - apoe KW - CNS disease KW - system KW - multiple sclerosis KW - MSSS KW - experimental autoimmune encephalomyelitis KW - disease severity KW - cognitive function KW - Alzheimer disease Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-136252 VL - 12 IS - 234 ER - TY - THES A1 - Sandwick, Sarah T1 - Suppression of Experimental Autoimmune-Encephalomyelitis by Myeloid-Derived Suppressor Cells T1 - Suppression der Experimentellen Autoimmun-Enzephalomyelitis durch Myeloide Suppressorzellen N2 - Autoimmune diseases, unwanted overshooting immune responses against self antigens, are due to an imbalance in immunity and tolerance. Although negatively impacting cancer prognosis, myeloid derived suppressor cells (MDSC), with their potent suppressive capabilities, might be applicable in a more beneficial light when applied in to autoimmunity. As previous shown MDSC have protective roles in Experimental Autoimmune Encephalomyelitis (EAE) (Zhu et al., 2007), the established inducible mouse model for the autoimmune disease multiple sclerosis (MS). This decrease in disease severity indicates in vitro generated immature myeloid cells (IMC) from bone marrow (BM) as precursors of MDSC are promising candidates for cellular therapy. Important to any cellular therapy by adoptive transfer, the major questions regarding IMC efficacy was addressed within the thesis. This thesis attempts to elucidate how IMC operate in EAE. This thesis defines the factors within the autoimmune microenvironment that lead to the activation of MDSC, where IMC home once delivered in vivo, and the protective mechanisms BMIMC employ. To emulate BM cells when they first enter circulation through the blood, IMC were injected intravenously (i.v.). IMC are protective with no regard to the various routes delivered (i.v., i.p.). They protect to a lesser extent when pre-activated before injection. IMC suppress by causing a delay and/or by decreasing the severity of the disease via a mechanism yet determined. To understand the migration pattern of IMC after i.v. injection, in vivo kinetics experiments employing bioluminescence imaging were performed. This techinique allows for whole in vivo mouse imaging daily, allowing the tracking of cell migration over days within a single mouse. During steady-state, BMIMC circulate and appear to accumulate in the spleen by day 4 after injection, whereas they alternatively home to inflammatory sites (immunization site), draining lymph nodes, and the spleen within mice with low grade EAE. Visualization of CMDiI-labelled BMIMC by fluorescence microscopy could locate IMC injected cells outside the white pulp, as they were colocalizing in the regions stained with CD169 or outside, but not within the follicles of spleens on day 4. Consistant with these findings, the attempt to analyze the phenotype of these cells by flow cytometry was problematic as these cells seem to adhere strongly to collagen also indicating the cells are located in the collagenous area of the marginal zone and the red pulp.To determine factors influencing MDSC activation, we utilized different stimuli through a high throughput method detecting release of nitric oxide (NO). Extracts from yeast, fungi, and bacteria were observed to activate MDSC to produce nitric oxide. Surprisingly, material mimicking viral DNA (CpG) and RNA (poly I:C), and several self glycolipids, could not activate the MDSC to produce NO. Upon attempts to understand synergistic effects between microbial pathogens and host cytokines, IFNg was determined to boost the signal of pathogen stimuli, whereas IL17, another cytokine which causes pathology during EAE, and IFNb, a drug used in therapy to treat MS, did not cause any additional effects. Activation of MDSC was determined by the microbial pathogens components LPS, curdlan, and zymosan, to induce upregulation of B7H1 on the cell surface. MDSC did not increase any co-stimulatory markers, such as CD40, CD80, CD86, CD70, or the co-inhibitory marker, PDL2. On day 1 after EAE induction, endogenous MDSC populations when stimulated showed an increase in B7H1 expression and a downregulation of CD80. After further analysis, these cells were concluded to be mostly granulocytic cells (Ly6G+). As the B7H1 ligand PD1 is upregulated in chronic diseases and correlates to an exhausted phenotype, the PD1 : B7H1 interaction was a good candidate for the mechanism our cells may employ for their suppressive capacity. To investigate this interaction, fixed BM-IMC deficient in B7H1 were incubated with restimulated memory T cells. IMC deficient in B7H1 resulted in a significant loss of T cell suppression, as compared to the wildtype control BMIMC. To assess this interaction in vivo, we injected wildtype (WT) and B7H1-/- IMC into mice followed by induction of EAE to assess whether B7H1 mediated this suppression. The lack of B7H1 did not alter their suppressive capacity under these conditions, contrary to other findings which have described this interaction to be important in their suppressive capacity when administered post EAE induction (Ioannou et al., 2012). Interestingly, EAE mice pre-treated with IMC had similar amounts of cytokine production in the CNS after restimulation. Spleens from IMC injected mice had increased amounts of Arg-1 suggesting suppression is via oxidation or recruitment by soluble mediators may lead to this protection. We speculate this may inhibit T cell reactivation in the CNS. N2 - Autoimmunerkrankungen, unerwünschte, überschießende Immunantworten gegen Selbstantigene, resultieren aus einem Ungleichgewicht von Immunität und Toleranz. Obwohl sie einen negativen Einfluss auf Tumorerkrankungen haben, könnten Myeloide Suppressorzellen (MDSC) durch ihre potenten immunsuppressiven Eigenschaften, in einem besseren Licht bei Anwendung gegen Autoimmunerkrankungen erscheinen. Wie zuvor gezeigt, können MDSC eine protektive Rolle bei der Experimentellen Autoimmunenzephalomyelitis (EAE) entfalten, dem etablierten induzierbaren Mausmodel für die Autoimmunerkrankung Multiple Sklerose (MS). Die Verminderung der Erkrankungssymptome deutet darauf hin, dass in vitro aus Knochenmark generierte unreife myeloide Zellen (IMC) als Vorläufer von MDSC viel versprechende Kandidaten für eine Zelltherapie darstellen. Da für jede Art der Zelltherapie die Effektivität der transferierten Zellen eine entscheidende Rolle spielt, sollte in dieser Arbeit die Funktionalität von IMC untersucht werden. Diese Dissertation erarbeitet wie IMC bei der EAE funktionieren. Die Arbeit versucht die Faktoren innerhalb der AutoimmunMikroumgebung zu definieren, welche zur MDSC Aktivierung führen, wohin applizierte IMC in vivo wandern und welche protektiven Mechanismen IMC anwenden. Um nachzubilden, wie BM Zellen bei ihrem Eintritt in das Blut sich in der Zirkulation verhalten, wurden IMC intravenös injiziert. Die injizierten gemischten IMC verhielten sich protektiv, unabhängig von der Art der Injektion (iv, ip). Sie sind jedoch weniger protektiv, wenn sie voraktiviert injiziert wurden. IMC supprimieren auf eine Weise, dass sie eine Verzögerung und/oder Verminderung der Erkrankungssymptome bewirken, wobei die dafür zugrunde liegenden Mechanismen noch nicht definiert sind. Um die Wanderungsmuster der BMIMC nach iv Injektion zu verstehen, wurden in vivo Kinetikexperimente mittels der Biolumineszenz-Darstellung durchgeführt. Diese Technik erlaubt eine tägliche Betrachtung der gesamten lebenden Maus, so dass die Zell-Wanderungsmuster über Tage in derselben Maus aufgezeichnet werden können. Unter homöostatischen Bedingungen zirkulieren IMC bis sie nach 4 Tagen in der Milz akkumulieren, wogegen sie alternativ zu Entzündungsherden wandern (Immunisierungssstelle), in Lymphknoten und Milz in Mäusen mit milden EAE Symptomen. Deren Lokalisierung konnte durch Fluoreszenzmikroskopie von CMDiI-markierten IMC in der roten Pulpa der Milz an Tag 4 lokalisiert werden. In Übereinstimmung mit diesem Befund, waren durchflusszytometrische Phänotyp-Analysen problematisch, da die Zellen fest an Kollagenfasern gebunden schienen, was als weiterer Hinweis auf ihre Kollagenbindung dienen kann. Um Faktoren zur Aktivierung zu bestimmen, wurden verschiedene MDSC Stimuli benutzt und deren Freisetzung von Stickstoffmonoxid (NO) mittels einer Hochdurchsatzmethode bestimmt. Es konnte nachgewiesen werden, dass Extrakte aus Hefen, Pilzen und Bakterien MDSC aktivieren und zur NO Produktion führen. Überraschenderweise konnten DNS (CpG) oder RNS-Bestandteile (Poly I:C) mit viralen Charakteristika oder verschiedenen Selbst-Glykolipide keine NO Freisetzung hervorrufen. Darüber hinaus konnte für das Zytokin IFNg eine wichtige verstärkende Rolle gezeigt werden, wobei ein anderes bei der EAE-Pathogenese beteiligte beteiligtes Zytokin, IL17, und auch IFNb, eine Substanz zur Therapie der MS, keinerlei Effekte zeigten. Untersuchungen nach MDSC-Aktivierung mit den mikrobiellen Komponenten LPS, Curdlan und Zymosan zeigten eine Hochregulation des B7H1 Moleküls auf der Zelloberfläche. Andere kostimulatorische Marker, wie CD40, CD80, CD86, CD70 oder der inhibitorische Marker PDL2 nahmen nicht zu. Einen Tag nach EAE-Induktion exprimierten auch die endogene MDSC Populationen nach Stimulation eine erhöhte B7H1 und eine erniedrigte CD80 Expression. Nach weiterer Analyse konnten diese Zellen überwiegend als granulozytär (Ly6G+) eingestuft werden. Da der B7H1-Ligand PD1 bei chronischen Erkrankungen hochreguliert wird, und mit einem verbrauchten Phänotyp korreliert, sollte die PD1:B7H1 Interaktion als guter Kandidat für den Suppressionsmechanismus untersucht werden. Fixierte B7H1-defiziente IMC wurden auf ihre Suppressorfunktion auf Gedächtnis-T-Zellen getestet. B7H1-defiziente IMC zeigten eine signifikant niedrigere Suppression, im Vergleich zu Wildtyp IMC. Um diese Interaktion in vivo zu untersuchen, wurden Wildtyp oder B7H1defiziente IMC in Mäuse injiziert und danach EAE induziert um auch hier eine B7H1-vermittelte Suppression nachzuweisen. Die Abwesenheit von B7H1 veränderte jedoch die suppressiven Eigenschaften unter diesen Bedingungen nicht, im Gegensatz zu anderen beschriebenen Befunden bei denen eine wichtige suppresive Rolle bei Injektion nach EAE-Induktion beschrieben wurde. Interessanterweise zeigten Mäuse, welche mit BMIMC vorbehandelt wurden, eine vergleichbare Zytokinfreisetzung im ZNS nach Restimulation. Milzen zeigten nach IMC Injektion auch erhöhte Mengen Arg-1 könnte dies auf eine Suppression durch oxidative Mediatoren hindeuten. Man kann also annehmen, dass so eine Reaktivierung der T Zellen im ZNS verhindert wird. KW - Encephalomyelitis KW - Autoaggressionskrankheit KW - Suppressorzelle KW - Myeloblast KW - Experimentellen Autoimmun-Enzephalomyelitis KW - Myeloide Suppressorzellen KW - myeloid derived suppressor cells KW - experimental autoimmune encephalomyelitis Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-72690 ER -