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The numbers of monocytes and macrophages in the walls of cerebral blood vessels were counted on perfusion-fixed frozen brain sections (16 JLffi) of spontaneously hypertensive rats (SHR), stroke-prone SHR (SHR-SP), normotensive Wistar-Kyoto (WKY) rats, and young (16-week-old) and old (2-year-old) normotensive Sprague-Dawley rats (SD-l6w and SD-2y, respectively) using monoclonal antiborlies against rat macrophages (ED2). The staining was visualized with fluoresceinlabeled second antiborlies. The ED2-specific staining in brain sections was restricted to macrophages in a perivascular location. The number of perivascular cells per square millimeter of high-power field was significantly greater in SHR-SP (8.6 ± 2.1; n = 4) and SHR (6. 7 ± 0.9; n = 6) than in normotensive WKY (4.0 ± 0.5; n = 6; p <0.01). The number of perivascular macrophages was also greater in SD-2y (7.5 ± 2.7; n = 9) than in SD-l6w (2.9 ± 1.8; n = 8; p < 0.01). No ED2 staining was found in the resident microglia or in the endothelial cells, which were identified by double staining with rhodamine-labeled anti-factor VIII-related antigen antiborlies. The results suggest that the stroke risk factors hypertension and advanced age are associated with increased subendothelial accumulation of monocytes and macrophages. This accumulation could increase the tendency for the endothelium to convert from an anticoagulant to a procoagulant surface in response to mediators released from these subendothelial cells.
Mutationsanalyse des Gens für das Zelladhäsionsmolekül CELSR1bei familiärer katatoner Schizophrenie
(2003)
In einer kürzlich durchgeführten Kopplungsanalyse der periodischen Katatonie wurden zwei Genloci auf Chromosom 15 und auf Chromosom 22 identifiziert. Für den Genlocus auf Chromosom 22p13.3 wurde ein LOD-Score von 1,85 (p=0,0018) ermittelt. Bei einer Durchsicht der in der fraglichen Region auf Chromosom 22 lokalisierten Gene unter Berücksichtigung ihrer Funktion, erschien CELSR1 als eines der vielversprechendsten Gene, nicht zuletzt, da es relativ selektiv im Nervensystem exprimiert wird. CELSR1 ist ein zur Gruppe der Cadherine gehörendes Zelladhäsionsmolekül. Cadherine spielen eine wichtige Rolle bei der Entwicklung des Gehirns, da sie eine Art Zellsortiermechanismus darstellen, der die Bildung spezifischer Hirnnuclei durch Zellagreggation ermöglicht. Darüber hinaus sind sie an der synaptischen Plastizität, wie sie bei neuronalen Lernvorgängen vorkommt, beteiligt [Huntley, (2002); Skaper, (2001)]. CELSR1 bildet innerhalb der Cadherine eine eigene Subgruppe. Seine Funktion scheint zum einen in der frühen Embryonalentwicklung zu liegen, zum anderen ist das Drosophila-Ortholog Flamingo einer der wichtigsten Modulatoren des Dendritenwachstums. Dementsprechend erscheint CELSR1 als interessanter Kandidat für Schizophrenien, bei denen sowohl Störungen in der Embryogenese des Gehirns, als auch eine Dysregulation der synaptischen Plastizität diskutiert wird. CELSR1 wurde in einer mutmaßlichen Promotorregion, dem Exonbereich, Exon/Intron-Übergängen und einem polymorphen Intron auf Mutationen untersucht. DNA-Proben von zwei der erkrankten Familienmitgliedern und drei Kontrollen wurden sequenziert und die so erhaltene Sequenz mittels eines Online-Analyseprogramms verifiziert. Dabei wurden 18 Allelvarianten, 12 stumme Transitionen, fünf missense-Mutationen und eine Insertion entdeckt, die aber in keiner der Patientenproben exklusiv auftrat. Mit grosser Wahrscheinlichkeit enthält CELSR1 keine krankheitsverursachende Mutation Die gefundenen Polymorphismen stellen eine interessante Ausgangsbasis für Assoziationsstudien dar.
Das humane Chromosom 15 wurde bereits im Zusammenhang mit anderen Erkrankungen wie dem Marfan Syndrom und der Tay Sachs Erkrankung erwähnt. Für deren Genese wurden auf dem Chromosom gelegene Gene verantwortlich gemacht (Richard et al. 1994). Aufbauend auf den Vorarbeiten der Würzburger Arbeitsgruppe (Stöber et al. 2000, 2002; Meyer et al. 2002) wurden auf Chromosom 15 anhand der Lokalisation, der Funktion und dem Vorhandensein im Zentralnervensystem die Gene Cx36 und TYRO3 für die Mutationsanalyse ausgewählt, um sie nach der Methode von Sanger (Sanger et al. 1977) zu sequenzieren. Sowohl Cx36 als auch TYRO3 spielen eine zentrale Rolle in der Entwicklung und Zellinteraktion im ZNS. Es wäre denkbar, daß ein Defekt während der Synaptogenese im ZNS an der Krankheitsentstehung beteiligt ist, ebenso wie eine unzureichende Ausbildung von Gap junctions, an denen Cx36 maßgeblich beteiligt ist. Die Patienten-DNA wurde aus Blutproben von Probanden mit periodischer Katatonie gewonnen. Diese wurden aus der Familie 11 der bereits erwähnten Studie rekrutiert, die in drei Generationen von der Erkrankung betroffen ist und zehn gesunde, sowie 7 kranke Mitglieder zählt. Die Proben wurden zusammen mit solchen von gesunden Kontrollpersonen vergleichend sequenziert und auf Übereinstimmung mit den Einträgen der GenBank überprüft mit dem Ziel, Mutationen zu finden, die zu einem Defekt im Protein führen und zur Ausprägung der Krankheit beitragen, bzw. die Gene als Kandidaten auszuschließen.
Glukose ist einer der Hauptenergielieferanten der Säugetierzellen. Aus diesem Grund wird die Glukoseaufnahme durch erleichterte Diffusion durch die GLUT (SLC2) Familie, sowie durch die Familie der sekundär aktiven Transporter SGLT (SLC5A) gesichert. In dieser Arbeit wurde ein polyklonaler Antikörper gegen SGLT1 aus Kaninchen hergestellt. Dieser Antikörper wurde für die Innunhistologie sowie für Western blots eingesetzt. Man sah eine Anfärbung von Bürstensaummembranen an Dünndarm- und Nierentubulusepithelzellen, aber in diesen Geweben nicht an Mikrogefäßen. Darüberhinaus konnten wir SGLT1 an der basolateralen Membran von Speicheldrüsenazini sehen, auch hier konnten wir SGLT1 in den Kapillaren nicht sehen. Überraschenderweise konnte SGLT1 in der Blut-Hirn-Schranke nachgewiesen werden. Auch konnte man die Lokalisation von SGLT1 in den Kapillaren des Herzens und des Skelettmuskels zeigen. Die physiologische und pathophysiologische Bedeutung dieser Lokalisationen liegt noch im Unklaren.
Epithelial and endothelial cells (EC) are building paracellular barriers which protect the tissue from the external and internal environment. The blood-brain barrier (BBB) consisting of EC, astrocyte end-feet, pericytes and the basal membrane is responsible for the protection and homeostasis of the brain parenchyma. In vitro BBB models are common tools to study the structure and function of the BBB at the cellular level. A considerable number of different in vitro BBB models have been established for research in different laboratories to date. Usually, the cells are obtained from bovine, porcine, rat or mouse brain tissue (discussed in detail in the review by Wilhelm et al. 1). Human tissue samples are available only in a restricted number of laboratories or companies 2,3. While primary cell preparations are time consuming and the EC cultures can differ from batch to batch, the establishment of immortalized EC lines is the focus of scientific interest.
Here, we present a method for establishing an immortalized brain microvascular EC line from neonatal mouse brain. We describe the procedure step-by-step listing the reagents and solutions used. The method established by our lab allows the isolation of a homogenous immortalized endothelial cell line within four to five weeks. The brain microvascular endothelial cell lines termed cEND 4 (from cerebral cortex) and cerebEND 5 (from cerebellar cortex), were isolated according to this procedure in the Förster laboratory and have been effectively used for explanation of different physiological and pathological processes at the BBB. Using cEND and cerebEND we have demonstrated that these cells respond to glucocorticoid- 4,6-9 and estrogen-treatment 10 as well as to pro-infammatory mediators, such as TNFalpha 5,8. Moreover, we have studied the pathology of multiple sclerosis 11 and hypoxia 12,13 on the EC-level. The cEND and cerebEND lines can be considered as a good tool for studying the structure and function of the BBB, cellular responses of ECs to different stimuli or interaction of the EC with lymphocytes or cancer cells.
Susac syndrome, a rare but probably underdiagnosed combination of encephalopathy, hearing loss, and visual deficits due to branch retinal artery occlusion of unknown aetiology has to be considered as differential diagnosis in various conditions. Particularly, differentiation from multiple sclerosis is often challenging since both clinical presentation and diagnostic findings may overlap. Optical coherence tomography is a powerful and easy to perform diagnostic tool to analyse the morphological integrity of retinal structures and is increasingly established to depict characteristic patterns of retinal pathology in multiple sclerosis. Against this background we hypothesised that differential patterns of retinal pathology facilitate a reliable differentiation between Susac syndrome and multiple sclerosis. In this multicenter cross-sectional observational study optical coherence tomography was performed in nine patients with a definite diagnosis of Susac syndrome. Data were compared with age-, sex-, and disease duration-matched relapsing remitting multiple sclerosis patients with and without a history of optic neuritis, and with healthy controls. Using generalised estimating equation models, Susac patients showed a significant reduction in either or both retinal nerve fibre layer thickness and total macular volume in comparison to both healthy controls and relapsing remitting multiple sclerosis patients. However, in contrast to the multiple sclerosis patients this reduction was not distributed over the entire scanning area but showed a distinct sectorial loss especially in the macular measurements. We therefore conclude that patients with Susac syndrome show distinct abnormalities in optical coherence tomography in comparison to multiple sclerosis patients. These findings recommend optical coherence tomography as a promising tool for differentiating Susac syndrome from MS.
We earlier established a model of a persistent viral CNS infection using two week old immunologically normal (genetically unmodified) mice and recombinant measles virus (MV). Using this model infection we investigated the role of regulatory T cells (Tregs) as regulators of the immune response in the brain, and assessed whether the persistent CNS infection can be modulated by manipulation of Tregs in the periphery. CD4\(^+\) CD25\(^+\) Foxp3\(^+\) Tregs were expanded or depleted during the persistent phase of the CNS infection, and the consequences for the virus-specific immune response and the extent of persistent infection were analyzed. Virus-specific CD8\(^+\) T cells predominantly recognising the H-2D(b)-presented viral hemagglutinin epitope MV-H22-30 (RIVINREHL) were quantified in the brain by pentamer staining. Expansion of Tregs after intraperitoneal (i.p.) application of the superagonistic anti-CD28 antibody D665 inducing transient immunosuppression caused increased virus replication and spread in the CNS. In contrast, depletion of Tregs using diphtheria toxin (DT) in DEREG (depletion of regulatory T cells)-mice induced an increase of virus-specific CD8\(^+\) effector T cells in the brain and caused a reduction of the persistent infection. These data indicate that manipulation of Tregs in the periphery can be utilized to regulate virus persistence in the CNS.
Behavioural Analyses of Quinine Processing in Choice, Feeding and Learning of Larval Drosophila
(2012)
Gustatory stimuli can support both immediate reflexive behaviour, such as choice and feeding, and can drive internal reinforcement in associative learning. For larval Drosophila, we here provide a first systematic behavioural analysis of these functions with respect to quinine as a study case of a substance which humans report as "tasting bitter". We describe the dose-effect functions for these different kinds of behaviour and find that a half-maximal effect of quinine to suppress feeding needs substantially higher quinine concentrations (2.0 mM) than is the case for internal reinforcement (0.6 mM). Interestingly, in previous studies (Niewalda et al. 2008, Schipanski et al 2008) we had found the reverse for sodium chloride and fructose/sucrose, such that dose-effect functions for those tastants were shifted towards lower concentrations for feeding as compared to reinforcement, arguing that the differences in dose-effect function between these behaviours do not reflect artefacts of the types of assay used. The current results regarding quinine thus provide a starting point to investigate how the gustatory system is organized on the cellular and/or molecular level to result in different behavioural tuning curves towards a bitter tastant.
Face processing can be explored using electrophysiological methods. Research with event-related potentials has demonstrated the so-called face inversion effect, in which the N170 component is enhanced in amplitude and latency to inverted, compared to upright, faces. The present study explored the extent to which repetitive lower-level visual cortical engagement, reflected in flicker steady-state visual evoked potentials (ssVEPs), shows similar amplitude enhancement to face inversion. We also asked if inversion-related ssVEP modulation would be dependent on the stimulation rate at which upright and inverted faces were flickered. To this end, multiple tagging frequencies were used (5, 10, 15, and 20 Hz) across two studies (n=21, n=18). Results showed that amplitude enhancement of the ssVEP for inverted faces was found solely at higher stimulation frequencies (15 and 20 Hz). By contrast, lower frequency ssVEPs did not show this inversion effect. These findings suggest that stimulation frequency affects the sensitivity of ssVEPs to face inversion.
Background: Because most human stroke victims are elderly, studies of experimental stroke in the aged rather than the young rat model may be optimal for identifying clinically relevant cellular responses, as well for pinpointing beneficial interventions.
Methodology/Principal Findings: We employed the Affymetrix platform to analyze the whole-gene transcriptome following temporary ligation of the middle cerebral artery in aged and young rats. The correspondence, heat map, and dendrogram analyses independently suggest a differential, age-group-specific behaviour of major gene clusters after stroke. Overall, the pattern of gene expression strongly suggests that the response of the aged rat brain is qualitatively rather than quantitatively different from the young, i.e. the total number of regulated genes is comparable in the two age groups, but the aged rats had great difficulty in mounting a timely response to stroke. Our study indicates that four genes related to neuropathic syndrome, stress, anxiety disorders and depression (Acvr1c, Cort, Htr2b and Pnoc) may have impaired response to stroke in aged rats. New therapeutic options in aged rats may also include Calcrl, Cyp11b1, Prcp, Cebpa, Cfd, Gpnmb, Fcgr2b, Fcgr3a, Tnfrsf26, Adam 17 and Mmp14. An unexpected target is the enzyme 3-hydroxy-3-methylglutaryl-Coenzyme A synthase 1 in aged rats, a key enzyme in the cholesterol synthesis pathway. Post-stroke axonal growth was compromised in both age groups.
Conclusion/Significance: We suggest that a multi-stage, multimodal treatment in aged animals may be more likely to produce positive results. Such a therapeutic approach should be focused on tissue restoration but should also address other aspects of patient post-stroke therapy such as neuropathic syndrome, stress, anxiety disorders, depression, neurotransmission and blood pressure.