SCHWERPUNKT
NEUROWISSENSCHAFTEN
INNSBRUCK

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Forschungsprojekte des SNI

Genehmigte IFTZ-Anträge 2007 von SNI Mitgliedern

Projektnummer: 1
Reticulon proteins in the epileptic brain
Christine E. Bandtlow ( Sektion für Neurobiochemie ), Günther Sperk (Institut für Pharmakologie)
Kooperationspartner extern: Paolo Macchi (Hirnforschungsinstitut, MUW, Wien), Mathias Klugmann (Mainz, Deutschland), Martin Korte ( Braunschweig, Deutschland)

Abstract:
The major experimental approach to be employed in this project is to analyse if and how RTN-4A and RTN-1A can contribute to lasting structural and functional changes underlying limbic epileptogenesis in the adult brain. RTN-4A/Nogo-A and RTN-1A, two members of the reticulon protein family, have been implicated in neuronal differentiation and plasticity. Our strategy is based on our recent discovery that acute knockdown of RTN-4A/Nogo-A or RTN-1A in cultured embryonic neurons or organotypic hippocampal slice cultures by RNAi revealed that RTN-4A and RTN-1A exert distinct but opposing regulatory functions on axonal and dendritic growth. It is our hypothesis that RTN-4A/Nogo-A promotes axonal and dendritic sprouting, while expression of RTN-1A ceases neurite growth and stabilizes neuronal connectivity. A well described model system to study axonal sprouting and synaptic reorganisation in vivo is the epileptic brain. Interestingly, Nogo-A was shown to be up-regulated in neurons and sprouting fibers in both the experimental and human temporal lobe epilepsy. However, the role of Nogo-A in mossy fiber sprouting (MFS) relative to epileptogenesis is unknown. In the present proposal we seek to test the hypothesis that introduction of viral vectors expressing short hairpin RNAs (shRNAs) directed against Nogo-A or RTN-1A would affect pathology and seizures in a rat model of temporal lope epilepsy.

Projektnummer: 2
Antibodies to myelin oligodendrocyte glycoprotein as biological marker in multiple sclerosis: progressing from bench to bedside
Thomas Berger, Markus Reindl (Univ.-Klinik für Neurologie)
Kooperationspartner intern: Georg Dechant ( Gem. Einrichtung für Neurowissenschaften), Michael Schocke (Univ.-Klinik für Radiodiagnostik 1)
Kooperationspartner extern: Eberhard Fuchs (Göttingen, Deutschland), Wolfgang Brück (Göttingen, Deutschland)

Abstract:
The overall goal of our project is to identify relevant antibodies (antibodies to MOG and AP4, as well as novel antibodies) as biological markers in MS. Therefore we aim to identify and characterize pathogenic antibodies in-vitro and in-vivo (non-human primates and MS patients), and to correlate these antibodies with clinical and MRI features, as well as treatment responses of MS patients.
The specific aims of our project are:
•  To identify pathogenic anti-MOG and anti-AP4 antibodies using cell-based and fluid-phase immunoassays
•  To identify novel anti-CNS antibodies in MS using immunocytochemistry
•  To analyze the pathogenic role of these antibodies in-vitro and in-vivo
•  To correlate these antibodies with clinical data of MS patients
•  To correlate these antibodies with MRI features of brain inflammation
•  To use these antibodies as biomarkers to identify MS patients who benefit from B-cell and antibody directed therapies
•  To finally establish translational projects for broad clinical use of the identified biomarkers

Projektnummer: 3
Spinocerebellar ataxia type 2 (SCA2): The role of MID1 in the expression of ataxin2 and its inhibition via lithium
Sylvia Bösch (Univ.-Klinik für Neurologie)
Kooperationspartner intern: Gregor K. Wenning, K. Seppi, W. Poewe ( Univ.-Klinik für Neurologie ), Michael Schocke (Univ.-Klinik für Radiodiagnostik 1);
Kooperationspartner extern: Rainer Schneider (Institut für Biochemie, Universität Innsbruck), Susann Schweiger (Berlin, Deutschland)

Abstract:
Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant ataxia that is clinically characterized by progressive ataxia and dysarthria associated with the ocular abnormalities. Mean age of onset is typically in adulthood. Disease alleles have 32 or more CAG repeats on chromosome 12q24.13. T he ATXN2 gene product (ataxin-2) is localized in the cytoplasma. The biologic consequence of the abnormal ataxin-2 protein is undetermined. Currently there is no treatment available for the disease.
Still, there might be a correlation between SCA2 and a newly described translational regulator of polyCAG containing mRNAs called MID1.MID1 (midline 1 protein) is a mRNA-sequence specific positive, translational regulator which appears to be involved in localized protein production in the cell. It has a high preferential binding to G-rich and trinucleotide repeat (CAG) n mRNA regions. In the presence of poly(CAG) stretches, the interaction of MID1 with these structures appears to be directly proportional to the length of the repeat. Preliminary experiments show an interaction between the positive translational regulator MID1 and G-rich and trinucleotide repeat (CAG) n mRNA regions that can be compromized by lithium ions.
The goals of this translational project are (1) The development and validation of an ataxin-2 assay which differentiates between the normal and mutated ataxin-2 (MW about 145 kD). A new method will be applyied to obtain 10 to 15 kD protein fragments of ataxin-2 containing the polyQ region. This will allow the quantitative detection mutant and normal ataxin-2 on Westernblots using a fragment-specific antibody. (2) To investigate the role of MID1 in SCA2 using lymphoblastoid cell lines from SCA2 patients and age-matched control subjects (analysed for ataxin-2 expression). Binding assays that report the affinity of MID1 and SCA2mRNA will be developed (3) To validate MID1 as a therapeutic target in SCA2 (in-vitro). Aforementioned cell lines will be incubated with lithium and the expression rate of normal versus mutated ataxin-2 will be measured. Binding assays that report the affinity of MID1 and SCA2mRNA in the presence of lithium will be performed. (4) To investigate the role of lithium in a clinical pilot trial in SCA2 patients. In case of positive findings in our preclinical studies a clinical pilot trial in SCA2 patients (Phase IIa study “proof of concept”) using lithium will be performed. The final goal of our project is to study lithium as a possible treatment option for SCA2 and other polyglutamine disorders.

Projektnummer: 5
Titel des Projektes:
Cell Fate Analysis of Embryonal and Adult Stem Cell-Derived Grafts in the 6-OHDA Model of Parkinson's Disease
Antragsteller: Georg Dechant and Gregor Wenning

Abstract:
For the first time, we will directly compare the neurorestorative potential of mesencephalic precursor cells, embryonic stem cells and adult mesenchymal stem cells in parallel experiments under highly standardized experimental conditions. This will help to discriminate between cell-type intrinsic properties and experimental variables that depend on tissue handling procedures. Dopaminergic grafts derived from all three populations will be transplanted to the striatum in the 6-OHDA rat model of PD. Primary outcome measure will be functional integration as determined by established motor behavior tests. Further, we aim the refinement of cell culture protocols, which are tailored specifically for the generation of A9 neurons or their immediate precursors An optimized set of stage specific marker genes will help us to monitor the progress of the cells along the A9 cell lineage in vitro   Finally, o ur project will comprise a comprehensive and strictly quantitative molecular characterization of cell fate and cell lineage decisions that occur in the grafted cells before and after transplantation.

Projektnummer: 14
NOGO receptors in nociception
Michaela Kress ( Sektion für Physiologie ), Christine E. Bandtlow ( Sektion für Neurobiochemie)

Abstract:
NGR1 and NGR2 null mutant mice exhibit increased mechanical sensitivity. The changes responsible for the phenotype may either be located at the peripheral nociceptive nerve terminal or at the site of synaptic transmission in the dorsal horn of the spinal cord. Although candidate gene approaches have yielded several ion channels that are expressed in mammalian somatosensory neurons, none of these channels has been shown to be essential for mechanotransduction. Moreover, the diversity of mechanosensitive cells suggests that multiple mechanisms underlie transduction. In order to elucidate the mechanism of the increased mechanosensitivity in NGR KO mice, we will address the question whether primary afferent nociceptors derived from NGR KO mice are different from those of wildtype animals. The project will further investigate whether nociceptive wiring and synaptic transmission in the spinal dorsal horn are altered in NGR KO mice. Finally, we will identify the differences in gene expression between KO and wildtype mice in the DRG and spinal cord dorsal horn that account for the increased mechanosensitivity. The overall aim of the project is to identify molecules that mediate mechanotransduction and this is an essential step in elucidating mechanisms that initiate touch and pain. This will also promote our understanding of how sensory signalling is altered under conditions of inflammation and chronic pain.

Projektnummer: 18
Charakterisierung von Risiko- und Biomarkern der Parkinson-Krankheit
Prof. Dr. Klaus Seppi, Dr. Christoph Scherfler (Univ.-Klinik für Neurologie)
Kooperationspartner intern: Hans Willeit, Stefan Kiechl, Markus Reindl (Univ.-Klinik für Neurologie), Irene Virgolini ( Univ.-Klinik für Nuklearmedizin), Michael Schocke (Univ.-Klinik für Radiodiagnostik 1), Reinhard Kofler ( Sektion für Molekulare Pathophysiologie ), Florian Überall ( Sektion für Medizinische Biochemie ), Florian Kronenberg ( Sektion für Genetische Epidemiologie )
Kooperationspartner extern: Thomas Gasser, Daniela Berg (Tübingen, Deutschland), Steffi Behnke (Homburg, Deutschland)

Abstract:
Parkinson's disease (PD) is among the most common neurodegenerative disorders. Its prevalence increases with age and affects about 20000 of the people in Austria. Effective symptomatic therapies are available but there is currently no intervention that would modify disease progression. At the same time, there is convincing evidence of a latent phase of the illness where ongoing neurodegeneration does not yet produce overt parkinsonism. Estimates about the duration of this latent phase range from 4 to 6 years and it would be the logic target of interventions to aim at modifying disease progression in terms of preventing or delaying the onset of PD. In order to be able to test such “preventive” approaches in clinical trials, it is essential to identify subjects at increased risk to develop PD, who would then be the target population for disease modifying or neuroprotective therapies. Despite all recent advances there is currently no established imaging, genetic, proteomic, neurophysiological or CSF/blood marker associated with PD risk in healthy subjects.
The current project is aimed to validate five candidate risk markers against an established imaging marker of nigrostriatal terminal dysfunction ([18F]Dopa-PET, see below)– the core pathology of motor syndrome of PD. Markers to be evaluated include i) olfactory dysfunction by the “Sniffin' Sticks“ test, ii) the axonal integrity of the olfactory tract as assessed by diffusion-weighted imaging, iii) hyperechogenicity of the substantia nigra as measured by transcranial sonography, iv) serum alpha-synuclein levels and v) enhanced gene expressions measured by DNA microarray analysis. The predictive value of the above candidate markers to detect subclinical nigrostriatal terminal dysfunction will be calculated based on [18F]Dopa-PET scanning in subjects without parkinsonism as a reference standard. In addition, diagnostic accuracy (sensitivity, specificity, predictive values) will be calculated for hyposmia, nigral hyperechogenicity and alpha-synuclein levels in a population based approach by a 5 years follow-up to determine differential conversion rates between subjects with and without positive risk markers. To screen for potential risk markers we will use i) data obtained in an ongoing prospective population-based study of carotid atherosclerosis and stroke risk (The Bruneck-Study) and ii) pooled data from two larger cohort follow-up studies by our cooperating partners from the University of Tübingen und Homburg-Saar.
We hypothesize, that markers shown to be associated with preclinical presymptomatic nigro-striatal terminal dysfunction will be predictive for PD risk measured in clinical overt PD.

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