@phdthesis{Visan2003, author = {Visan, Ion Lucian}, title = {P0 specific T-cell repertoire in wild-type and P0 deficient mice}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-5734}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2003}, abstract = {Zusammenfassung Das Myelinprotein P0 stellt eine zentrale Komponente f{\"u}r die Stabilit{\"a}t und Funktionalit{\"a}t der Myelinscheiden des peripheren Nervensystems dar. Mutationen des P0-Proteins f{\"u}hren zu verschiedenen, schwer behindernden peripheren Neuropathien wie der Charcot-Marie-Tooth- oder der Dejerine-Sotas-Erkrankung. Wir haben das Tiermodell der P0-Knock-Out-M{\"a}use verwendet, um im Vergleich zu den C57BL/6-Wildtyp-Tieren Selektionsmechanismen des P0-spezifischen T-Zell-Repertoires zu untersuchen. Dazu wurde eine Reihe von {\"u}berlappenden 20-mer-Peptiden benutzt, die die gesamte Aminos{\"a}uresequenz von P0 abdeckten. Mit Hilfe dieser Peptide wurde ein sog. „Epitop-Mapping" der H2-Ab-restringierten T-Zell-Antwort durchgef{\"u}hrt. Auf diese Weise konnte das P0-Peptid 5 (Aminos{\"a}ure 41-60) in der extrazellul{\"a}ren P0-Dom{\"a}ne als immunogene Determinante identifiziert werden. Dieses immunogene Peptid wurde dann f{\"u}r Untersuchungen der Toleranzmechanismen verwendet und zeigte, dass in P0-Knock-Out-M{\"a}usen ein hochreaktives P0-spezifisches T-Zell-Repertoire vorliegt, w{\"a}hrend es in Wildtyp-Tieren inaktiviert ist und so Selbsttoleranz erzeugt wird. Die Toleranzerzeugung in Wildtyp- und heterozygoten P0 +/- M{\"a}usen h{\"a}ngt nicht von der Gen-Dosis ab. P0 ist ein gewebespezifisches Antigen, dessen Expression normalerweise auf myelinisierende Schwann-Zellen beschr{\"a}nkt ist. Die klassischen Vorstellungen zu Toleranzmechanismen gegen{\"u}ber gewebsspezifischen Antigenen schrieben diese vor allem peripheren Immunmechanismen zu. Durch den erstmaligen Nachweis von intrathymischer Expression gewebsspezifischer Antigene wie P0 konnten wir best{\"a}tigen, dass f{\"u}r P0 offensichtlich die Expression deutlich weiter verbreitet ist, insbesondere auch auf Thymus-Stroma-Zellen. Unter Verwendung von Knochenmarkschim{\"a}ren haben wir weitere Untersuchungen durchgef{\"u}hrt, wie Knochenmarks-abstammende Zellen im Vergleich zu nicht-h{\"a}matopoetischen Zellen Toleranz gegen{\"u}ber P0 erzeugen k{\"o}nnen. Unsere Befunde zeigen, dass Knochenmarks-abh{\"a}ngige Zellen nicht ausreichen, um v{\"o}llige Toleranz zu erzeugen. Zus{\"a}tzlich wurde eine P0-Expression auf anderen Geweben wie dem Thymus ben{\"o}tigt, um komplette Toleranz zu erhalten. Wir identifizierten ein kryptisches P0-Peptid 8 und zwei subdominante P0-Peptide 1 und 3. W{\"a}hrend das Peptid 8 sowohl in Wildtyp- als auch Knock-Out-M{\"a}usen erkannt wurde, wurden die Peptide 1 und 3 in Wildtyp-M{\"a}usen nicht als Immunogen erkannt. Die genannten Peptide wurden verwendet, um eine experimentelle autoimmune Neuritis (EAN) zu erzeugen. Mit keinem der experimentellen Ans{\"a}tze konnten wir klinische Zeichen einer EAN generieren, allerdings mit dem Peptid 3 doch Entz{\"u}ndung im peripheren Nerven beobachten. Es werden zuk{\"u}nftig weitere Untersuchungen ben{\"o}tigt, um P0-spezifische T-Zell-Linien zu etablieren und so mit h{\"o}herer Effizienz eine EAN zu erzeugen. Unsere Untersuchungen sprechen daf{\"u}r, dass bei gentherapeutischen Ans{\"a}tzen bei erblichen Neuropathien vorsichtig und schrittweise vorgegangen werden muss, da mit sekund{\"a}rer Autoimmunit{\"a}t und damit Inflammation im peripheren Nerven zu rechnen ist.}, subject = {Myelin}, language = {en} } @phdthesis{Fischer2008, author = {Fischer, Stefan Martin}, title = {Regulation and functional consequences of MCP-1 expression in a model of Charcot-Marie-Tooth 1B disease}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-29189}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2008}, abstract = {Charcot-Marie-Tooth 1B (CMT1B) is a progressive inherited demyelinating disease of human peripheral nervous system leading to sensory and/or motor function disability and is caused by mutations in the P0 gene. Mice heterozygously deficient for P0 (P0+/-) are an adequate model of this human disorder showing myelin degeneration, formation of onion bulbs, remyelination and a reduced motor conduction velocity of around 30m/s similar to patients. Previously, it had been shown that T-lymphocytes and macrophages play a crucial role during pathogenesis in peripheral nerves of P0+/- mice. Both, T-lymphocytes and macrophages increase in number in the endoneurium and deletion of T-lymphocytes or deletion of a macrophage-directed cytokine ameliorates the disease. In this study the monocyte chemoattractant protein-1 (MCP-1) was identified as an early regulated cytokine before onset of disease is visible at the age of six months. MCP-1 mRNA and protein expression could be detected in femoral quadriceps and sciatic nerves of P0+/- mice already at the age of one month but not in cutaneous saphenous nerves which are never affected by the disease. MCP-1 was shown to be expressed by Schwann cells and to mediate the immigration of immune cells into peripheral nerves. Deletion of MCP-1 in P0+/- mice accomplished by crossbreeding P0 and MCP-1 deficient mice revealed a substantial reduction of immune cells in peripheral nerves of P0+/-/MCP-1+/- and P0+/-/MCP-1-/- mice at the age of six months. In twelve months old mice reduction of immune cells in peripheral nerves is accompanied by amelioration of demyelinating disease in P0+/-/MCP-1+/- and aggravation of demyelinating disease in lumbar ventral roots of P0+/ /MCP-1-/- mice in comparison to P0+/ /MCP 1+/+ mice. Furthermore, activation of the MEK1/2-ERK1/2 signalling cascade could be demonstrated to take place in Schwann cells of affected peripheral nerves of P0+/- mice overlapping temporarily and spatially with MCP-1 expression. An animal experiment using a MEK1/2-inhibitor in vivo, CI-1040, revealed that upon reduction of ERK1/2 phosphorylation MCP-1 mRNA expression is diminished suggesting that the activation of the MEK1/2-ERK1/2 signalling cascade is necessary for MCP-1 expression. Additionally, peripheral nerves of P0+/- mice showing reduced ERK1/2 phosphorylation and MCP-1 mRNA expression also show reduced numbers of macrophages in the endoneurium. This study shows a molecular link between a Schwann cell based mutation and immune cell function. Inhibition of the identified signalling cascade might be a putative target for therapeutic approaches.}, subject = {Schwann-Zelle}, language = {en} } @phdthesis{KronerMilsch2008, author = {Kroner-Milsch, Antje}, title = {Role of immune cells in hereditary myelinopathies}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-28976}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2008}, abstract = {Myelin mutations in the central and peripheral nervous system lead to severely disabling, currently untreatable diseases. In this study, we used transgenic PLP overexpressing mice (PLPtg) as a model for central inherited myelinopathies, such as leukodystrophies, and heterozygously P0 deficient (P0+/-) mice as models for peripheral hereditary polyneuropathies. Both models are characterized by low grade nervous tissue inflammation. Macrophages and CD8+ T- lymphocytes contribute to the myelin pathology as shown by crossbreeding experiments with immunodeficient mice. Having shown the relevance of CD8+ T- lymphocytes in PLPtg mice, we investigated the influence of one major cytotoxic molecule (granzyme B) on neural damage. By generation of granzyme B deficient PLPtg bone marrow chimeras, we could demonstrate a reduction of myelin pathology and oligodendrocyte death. Taken together, granzyme B is at least partly responsible for the cytotoxicity induced neural damage in PLPtg mice. To further explore the role of immune modulation, we focussed on the influence of the coinhibitory molecule PD-1, a CD28-related receptor expressed on activated T- and B-lymphocytes. By investigating myelin mutants of the CNS and PNS (PLPtg and P0+/-) with an additional PD-1 deficiency, induced by crossbreeding or bone marrow chimerization, we found a significant increase of CD8+ T- lymphocytes and massive increase of the myelin pathology in both the CNS and PNS model. In PLPtg mice, absence of PD-1 increased oligodendrocyte apoptosis, clonal expansions and a higher propensity of CNS but not peripheral CD8+ T- cells to secrete proinflammatory cytokines. In P0+/- mice, absence of PD-1 lead to moderate motor and sensory disturbances, confirming the important role of PD-1 in immune homeostasis. Taken together, we identified granzyme B as an important effector agent of cytotoxic T-lymphocytes in PLPtg mice and PD-1 as a crucial player in regulating the effector cells in our models of central and peripheral myelinopathy. Alterations of this regulatory pathway lead to overt neuroinflammation of high pathogenetic impact. These results might help to understand mechanisms responsible for high clinical variability of polygenic or even monogenic disorders of the nervous system.}, subject = {Myelinopathie}, language = {en} } @phdthesis{Schwab2009, author = {Schwab, Nicholas}, title = {The importance of CD8\(^+\) T cells and antigen-presenting cells in the immune reaction of primary inflammatory versus degenerative diseases}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37330}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2009}, abstract = {The bidirectional influence of parenchymal cells and cells of the immune system, especially of antigen-presenting and CD8\(^+\) T cells, in situations of putative auto- immune pathogenicity and degeneration was the main topic of this thesis. In the first part, the influence of human muscle cells on antigen-presenting cells was investigated. In inflammatory myopathies prominent infiltrates of immune cells containing T cells and antigen-presenting cells like macrophages and dendritic cells are present. The hypothesis was that human myoblasts have an inhibiting influence on these antigen-presenting cells under homeostatic conditions. A dysfunction or impairment under inflammatory circumstances might contribute to the development of myopathic conditions. The surface analysis of dendritic cells cocultured with myoblasts showed that immature dendritic cells could be driven into a reversible semi- mature state with significantly elevated levels of CD80. These dendritic cells were additionally characterized by their inhibiting function on T-cell proliferation. It was also shown that the lysates of healthy myoblasts could strongly enhance the phagocytic ability of macrophages, which could help with muscle regeneration and which might be disturbed in myositis patients. The second part of this thesis was about the clonal specificity of CD8\(^+\) T cells in a mouse model with genetically induced over-expression of PLP in oligodendrocytes. Here, we could show that the cytotoxic T lymphocytes, which had previously been shown to be pathogenic, were clonally expanded in the CNS of the transgenic mice. The amino acid sequences of the corresponding receptor chains were not identical, yet showed some similarities, which could mean that these clones recognize similar antigens (or epitopes of the same antigen). The knockout of PD-1 in this setting allowed for an analysis of the importance of tissue immune regulation. It became evident that the absence of PD-1 induced a larger number of clonal expansions in the CNS, hinting towards a reduced threshold for clonal disturbance and activation in these T cells. The expansions were, however, not pathogenic by themselves. Only in the presence of tissue damage and an antigenic stimulus (in our case the overexpression of PLP), the PD-1 limitation exacerbated the immune pathogenicity. Therefore, only in the presence of a "tissue damage signal", the dyshomeostasis of T cells lacking PD-1 achieved high pathogenetic relevance. Finally, we investigated the pathogenetic role of CD8 T cells in Rasmussen encephalitis, a rare and chronic neurological disease mainly affecting children. The analysis of the T-cell receptor repertoire in Rasmussen encephalitis patients in the peripheral CD4\(^+\) and CD8\(^+\) T-cell compartments as well as the brain revealed the involvement of T cells in the pathogenicity of this disease. Many clonal expansions in the brain matched CD8\(^+\) T-cell expansions in the periphery on the sequence level. These putatively pathogenic clones could be visualized by immunohistochemistry in the brain and were found in close proximity to astrocytes and neurons. Additionally, the expanded clones could be found in the periphery of patients for at least one year.}, subject = {T-Lymphozyt}, language = {en} } @phdthesis{Kohl2009, author = {Kohl, Bianca Dorothea}, title = {PMP22-overexpressing mice as a model for Charcot-Marie-Tooth 1A neuropathy implicate a role of immune-related cells}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-43066}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2009}, abstract = {Charcot-Marie-Tooth disease (CMT) is a cohort of human hereditary disorders of the peripheral nervous system (PNS) which exhibit symptoms like sensory dysfunction, muscle weakness and gait disturbances. Different mutations are described as causation for this neuropathy, such as a duplication of chromosome 17 comprising the gene for the peripheral myelin protein-22 (PMP22). Based on different animal models former studies identified immune cells, i.e. macrophages and T-lymphocytes, as crucial mediators of pathology in these neuropathies. In this study, PMP22-overexpressing mice (PMP22tg, C61), serving as a model for a specific type of CMT - CMT1A - were crossbred with immune-deficient mutant mice to examine the impact of the immune system on nerve pathology. Crossbreeding of PMP22tg mice with recombination activating gene-1 (RAG-1) deficient mice, lacking mature T- and B-lymphocytes, caused no striking alterations of pathogenesis in peripheral nerves of mutant mice. In contrast, crossbreeding of PMP22tg myelin mutants with mice deficient in the chemokine monocyte chemoattractant protein-1 (MCP-1, CCL2) caused an amelioration of the demyelinating phenotype of peripheral nerves when MCP-1 was either reduced or completely absent. Furthermore, functional investigations, i.e. neurographic recordings and examinations of the grip strength of the extremities, revealed an amelioration in PMP22tg/MCP-1-/- mice in regard to a symptomatic improvement in the compound action muscle potential (CMAP) and stronger grip strength of the hindlimbs. Interestingly, peripheral nerves of PMP22tg mice showed an irregular distribution of potassium channels in presence of MCP-1, whereas the absence of MCP-1 in the myelin mutants rescued the ion channel distribution and resulted in a more wild type-like phenotype. Having shown the impact of MCP-1 as an important mediator of nerve pathology in PMP22/MCP-1 double mutants, the regulation of this chemokine became an important target for potential treatment strategies. We found that the signaling cascade MEK1/2/ERK1/2 was more strongly activated in peripheral nerves of PMP22tg mice compared to nerves of wild type mice. This activation corresponded to an increase in MCP-1 mRNA expression in peripheral nerves at the same age. Furthermore, a MEK1/2-inhibitor was used in vivo to confirm the regulation of MCP-1 by the MEK1/2/ERK1/2 pathway. After a treatment period of three weeks, a clear reduction of ERK1/2-phosphorylation as well as a reduction of MCP-1 mRNA expression was observed, accompanied by a decline in macrophage number in peripheral nerves of PMP22tg mice. These observations suggest that the expression of MCP-1 is crucial for the neuropathological progression in a mouse model for CMT1A. Therefore, this chemokine could provide a basis for a putative treatment strategy of inherited neuropathies.}, subject = {Myelin}, language = {en} } @phdthesis{He2009, author = {He, Lan}, title = {Small fiber involvement in Fabry's disease}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32844}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2009}, abstract = {Aim of Investigation: The neurological manifestations of Fabry's disease, a rare, X-linked, multisystem disorder caused by alpha-galactosidase A deficiency and globotriosylceramide (Gb3) accumulation, include both peripheral and central nervous system symptoms. Here we evaluated a prospectively recruited cohort of patients with Fabry's disease for pain, small nerve fiber function, and skin innervation. Methods: 66 patients (31 male and 35 female) were enrolled\&\#65292;31 patients were on ERT. All patients underwent quantitative sensory testing (QST), electrophysiological examination, and extra- and transcranial Doppler sonography. For pain and mood assessment standardized questionnaires were used. Skin biopsies were performed at the left distal leg in 38 patients for intraepidermal nerve fiber density (IENFD) assessment. Results: Age at examination did not differ significantly between women (40.2+/-16.2 years) and men (38.9+/-13.8; n.s.). 29/31 male and 19/35 female patients complained of acroparesthesias or neuropathic pain. QST abnormalities indicative of small fiber impairment were found in 26/31 male and 28/35 female patients. Electrophysiological examination of large fibers and autonomic fibers revealed pathological findings in 11/31 male and 3/35 female patients. All patients had normal Doppler sonography results. Indicators for depression were present in 14/31 male and 10/35 female patients. 20/31 male and 18/35 female patients had a skin biopsy, the IENFD was significantly reduced in male (2.0+/-2.8 fibers/mm) compared with female patients (6.7 +/- 4.4 fibers/mm). In 10 patients free from neurological symptoms, QST and IENFD abnormalities were still detected. Follow up examination after one year in 12 patients under ERT (2.1+/-1.7 years) showed improvement in some symptoms and in QST and neurophysiology in six patients with normal renal function. 20/35 female patients older than 40 y had concomitant diseases, while none of the 18 younger female patients did. The corresponding radio in male patients was 5/19 (>=40y) and 2/13 (<40y) respectively. Conclusions: Neuropathic pain and sensory deficits of the distal extremities are common in patients with Fabry's disease. QST and IENFD analysis are important for early diagnosis of nerve involvement in Fabry's disease. Small fiber function may improve under ERT in patients without severe renal impairment.}, subject = {Fabry's disease}, language = {en} } @phdthesis{YuHwa2009, author = {Yu-Hwa, Huang}, title = {The Role of HLA-G-expressing Regulatory T cells in Multiple Sclerosis: A Perspective of Beneficial Inflammation in the Central Nervous System Inflammation}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39957}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2009}, abstract = {Die Regulation von Effektor-T-Zellen ist ein wichtiger Mechanismus zur Kontrolle organspezifischer Entz{\"u}ndungen. Dabei sind regulatorische T-Zellen (Treg) maßgeblich an der Aufrechterhaltung peripherer Immuntoleranz und parenchymaler Immunhom{\"o}ostase beteiligt. Eine neue Population von humanen, nat{\"u}rlich vorkommenden Treg Zellen wurde durch ihre konstitutive Expression des immuntolerogenen Molek{\"u}ls HLA-G identifiziert. Im ersten Teil dieser Arbeit wurden die Mechanismen, durch die CD4+ HLA-Gpos Treg Zellen ihre Zielzellen (autologe HLA-Gneg T-Zellen) modulieren, aufgekl{\"a}rt. Unter Verwendung eines Suppressionsansatzes in Abwesenheit von antigenpr{\"a}sentierenden Zellen (APC) wurden T-T-Zell-Interaktionen, die die Proliferation von HLA-Gneg T-Zellen hemmen, demonstriert. Diese Suppression, die durch die Stimulierung des T-Zell-Rezeptors auf HLA-Gpos Treg Zellen verst{\"a}rkt wurde, war unabh{\"a}ngig vom Zell-Zell-Kontakt. Die HLA-Gneg T-Zellen erlangten nach Entfernung der HLA-Gpos Treg Zellen und einer erneuten Stimulierung ihrer T-Zell- Rezeptoren ihre F{\"a}higkeit zur Proliferation wieder. Dies wies auf die Umkehrbarkeit dieser Suppression hin. Dar{\"u}ber hinaus war die HLA-Gpos Treg-vermittelte Suppression entscheidend von der IL-10- Sekretion, nicht jedoch von TGF-\&\#946; abh{\"a}ngig. Zusammengefasst beschreibt dieser Teil der Arbeit eine detaillierte Charakterisierung der Mechanismen, wie HLA-Gpos Treg HLA-Gneg TZellen supprimieren. Das tiefere Verst{\"a}ndnis der Wirkmechanismen von HLA-Gpos Treg k{\"o}nnte in therapeutischen Strategien verwendet werden, in denen die regulatorische Funktion der T-Zell-Suppression verst{\"a}rkt oder moduliert werden soll. Im zweiten Teil dieser Arbeit wurde die potenzielle Rolle von HLA-Gpos Treg bei der Multiplen Sklerose (MS) untersucht, einer klassischen Autoimmunerkrankung des Zentralnervensystems (ZNS). Im Gegensatz zu Vergleichspatienten mit nicht-entz{\"u}ndlichen Erkrankungen konnte im Liquor von MS Patienten eine erh{\"o}hte Anzahl von HLA-Gpos Treg gefunden werden. Diese aus dem Liquor isolierten HLA-Gpos Treg wiesen ph{\"a}notypische Merkmale von zentralen Ged{\"a}chtnis-T-Zellen (CD45RA- CD27+) auf, exprimierten den Aktivierungsmarker ICOS sowie deutlich h{\"o}here Level des Chemokinrezeptors (CCR) CCR5 und agierten als starke Suppressoren der autologen CD4+ T-Zellproliferation. Durch Verwendung eines in vitro Modells der humanen Bluthirnschranke konnte demonstriert werden, dass HLA-Gpos Treg eine starke Neigung zur Migration haben, die durch die CCR5- Liganden MIP1\&\#945; und RANTES, nicht jedoch durch MIP3\&\#946; (Ligand von CCR7) unterst{\"u}tzt wird. Diese Chemokin-induzierte Migration von HLA-Gpos Treg war auch mit einer Steigerung der suppressiven Kapazit{\"a}t nach Zelltransmigration assoziiert. Im Gegensatz zu CD4+CD25+, FoxP3-exprimierenden Treg zeigten HLA-Gpos Treg von MS-Patienten keine beeintr{\"a}chtigte Funktionalit{\"a}t. Dies deutet auf eine selektive Rekrutierung von HLA-Gpos Treg zu Entz{\"u}ndungsherden im ZNS und ihre Beteiligung an der Bek{\"a}mpfung der destruktiven Entz{\"u}ndung hin. Die Ergebnisse dieser Studien tragen zum weitergehenden Verst{\"a}ndnis der Rolle und Funktion HLA-Gpos Treg Zellen bei und stellen somit ein wichtiges pathophysiologisches Beispiel „gutartiger" T-Zell-Entz{\"u}ndung w{\"a}hrend der ZNS Autoimmunit{\"a}t dar, das sowohl aus pathophysiologischer als auch therapeutischer Sicht interessant ist.}, subject = {Regulatorische T-Zellen}, language = {en} } @phdthesis{Subramanian2011, author = {Subramanian, Narayan}, title = {Role of NaV1.9 in activity dependent axon growth in embryonic cultured motoneurons}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-57536}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2011}, abstract = {Spontaneous neural activity has been shown to regulate crucial events in neurite growth including axonal branching and path finding. In animal models of spinal muscular atrophy (SMA) cultured embryonic mouse motoneurons show distinct defect in axon elongation and neural activity. This defect is governed by abnormal clustering of Ca2+ channels in the axonal regions and the protruding growth cone area. The mechanisms that regulate the opening of calcium channels in developing motoneurons are not yet clear. The question was addressed by blocking neural activity in embryonic cultured motoneurons by pharmacological inhibition of voltage-gated sodium channels (VGSC) by saxitoxin (STX) and tetrodotoxin (TTX). Low dosages of STX resulted in significant reduction of axon growth and neural activity in cultured motoneurons. This pharmacological treatment did not affect survival of motoneurons in comparison to control motoneurons that was grown in the presence of survival neurotrophic factors BDNF and CNTF. It was also found that STX was 10 times more potent than TTX a common inhibitor of VGSC with a reduced activity on the TTX-insensitive sodium channels NaV1.5, NaV1.8 and NaV1.9. Reverse Transcriptase-PCR experiments revealed the presence of NaV1.9 as the likely candidate that begins to express from embryonic stage sixteen in the mouse spinal cord. Immunolabelling experiments showed that the channel is expressed in the axonal compartments and axonal growth cones in cultured motoneurons. Suppression of NaV1.9 in cultured motoneurons by lentivirus mediated short hairpin-RNA (shRNA) resulted in shorter axon length in comparison with uninfected and scrambled constructs. Further, embryonic motoneurons cultured from NaV1.9 knockout mice also showed a significant reduction in neural activity and axon growth. The findings of this work highlight the role of NaV1.9 as an important contender in regulating activity dependent axon growth in embryonic cultured motoneurons. NaV1.9 could therefore be considered as a prospective molecule that could play an important role in regulating axon growth in motoneuron disease models like spinal muscular atrophy (SMA).}, subject = {Axon}, language = {en} } @phdthesis{Schmid2012, author = {Schmid, Benedikt}, title = {Relation between cerebral arterio-venous transit time and neuropsychological performance in patients with vascular dementia}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-71234}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2012}, abstract = {Dementia, or any form of degenerative cognitive decline, is one of the major problems in present, and even more will be in future medicine. With Alzheimer's disease (AD) being the most prevalent, Vascular Dementia is the second most entity of dementing processes in the elderly. As diagnostic criteria are still imprecise and in many cases do not embrace early stages of the disease, recent studies have proposed more detailed classifications of the newly created condition Vascular Cognitive Impairment (VCI). Of all conditions subsumed under this term, subcortical small-vessel alterations are the most common cause for cognitive decline. The diagnosis of dementia / cognitive impairment is presently often made in late stages of the disease, when therapeutical options are poor. Thus, early detection of changes of the subcortical small vessels is desirable, when there is still time to identify and aggressively treat risk factors and underlying conditions like diabetes, hyper- or hypotension, and hyperlipidemia. This study aimed to evaluate whether cTT correlates to cognitive dysfunction, i.e. if cTT is fit as an early diagnostic tool for VCI. The study cohort included 38 patients from the Neurological Clinic of the W{\"u}rzburg University hospital admitted due to diagnoses other than dementia or stroke. As a result of this study it turned out that cTT is certainly capable of fulfilling the task to easily and effectively detect and evaluate possible microvascular lesions of the brain with respect to the actual clinical relevance for the patient. When compared to the other proposed diagnostic tools, neuropsychological testing and MRI, the advantages of cTT are obvious: its measurement is a low-cost and quick procedure which would spare both patients and examiners a long neuropsychological exam or complement it. cTT is safe to assess as the only possible risks derive from the use of the contrast agent, which are rare and easily manageable. It has also proven to be more accurate in showing the extent of cognitive impairment than MRI. Finally, it is widely available. The only prerequisite is an ultrasound machine capable of transcranial color-coded duplex sonography. No cost-intensive procedures like MRI are needed. So, with neuropsychological testing remaining the gold standard, cTT here proved to be a reliable alternative which is more time- and cost-effective than MRI.}, subject = {Demenz}, language = {en} } @phdthesis{Patzko2012, author = {Patzk{\´o}, {\´A}gnes}, title = {CSF-1 receptor as a target for the treatment of Charcot-Marie-Tooth disease 1}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-85325}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2012}, abstract = {Previous studies by our group revealed that chronic low grade inflammation implicating phagocytosing macrophages is a highly relevant mechanism in the pathogenesis of Charcot-Marie-Tooth disease. The lack of CSF-1, the primary regulator of macrophage function and survival, led to a robust and persistent amelioration of the phenotype in two authentic mouse models of CMT. Moreover, a close contact between CSF-1 producing fibroblasts and endoneurial macrophages carrying CSF-1R has been confirmed in nerve biopsies of CMT patients, further supporting the clinical significance of this pathway. In the current study we treated 3 distinct mouse models of CMT1: the PMP22tg mice as a model for CMT1A, the P0+/- mice as a model for CMT1B and the Cx32def mice as a model for CMT1X, with a CSF-1R specific kinase (c-FMS) inhibitor (800-1200 mg PLX5622/ kg chow) according to different treatment regimes mimicking an ideal early onset treatment, a late onset treatment and the withdrawal of the drug. Using the above mentioned doses of PLX5622, we documented a dramatic decrease in macrophage numbers in the PNS of all 3 myelin mutants, except for the quadriceps nerve of Cx32def mice. Fibroblast numbers remained unchanged in treated animals. Surprisingly, in spite of the decrease in the number of detrimental macrophages we could not detect an unequivocal phenotypic improvement. CMAP amplitudes were reduced in both wild type and myelin mutant mice treated with CSF-1R inhibitor in comparison to untreated littermates. Corresponding to the electrophysiological findings, the axon number and the percentage of large diameter axons were reduced in the quadriceps nerve of treated P0+/- and Cx32def mice. By contrast we observed a higher number of fully myelinated axons, in parallel with a decrease in the percentage of demyelinated (and hypermyelinated in PMP22tg mice) fibers in the ventral roots of P0+/- mice treated with CSF-1R inhibitor from 3 months up to 6 months of age and PMP22tg animals treated from 9 months up to 15 months of age. Our results indicate that CSF-1R inhibitor has the potential to improve the demyelinating phenotype of at least two models of CMT1. Nevertheless, further studies are necessary (for example with lower doses of the inhibitor) to minimize or even eliminate the putative neurotoxic effect we observed with high dose treatment conditions.}, subject = {Makrophage}, language = {en} }