Aguzzi
Fakultäten » Medizinische Fakultät » Neuropathologie, Institut für » Prof. Dr. Adriano Aguzzi » Aguzzi
Completed research project
| Title / Titel | Analysis of the physiological and pathological role of prion protein by proteomic approach in vivo | ||||
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| Abstract (PDF, 14 KB) | |||||
| Summary / Zusammenfassung | Prion diseases are invariably lethal and include Creutzfeldt-Jakob Disease (CJD) in humans, and Bovine Spongiform Encephalopathy (BSE), Scrapie, and Chronic Wasting Disease (CWD) in farm and wild-ranging animals. Transmission of BSE to humans had caused more than 200 cases of a new variant of CJD (vCJD), of which four cases of human-to-human prion transmission via blood transfusions were reported. Therefore BSE prions can be recycled among humans. The risk that individuals with subclinical BSE or CJD prion infections can transmit these prions to others warrants the development of rapid and sensitive tests for prion or surrogate markers. The central event in prion pathogenesis is the conformational conversion of cellular prion protein (PrPc), a cell surface glycoprotein of unknown function, into PrPSc, an insoluble and protease-resistant isoform, that propagates itself by imposing its abnormal conformation onto PrPc molecules. The precise mechanism of this conversion process, and the nature of the neurotoxic pathways activated by PrPSc, is unknown. A key question in the field is whether neurotoxicity is mediated by aberrant, novel interactions with the PrPSc. We examined protein complexes from mouse brain and we are able to show for the first time, that PrPc assembles into large stable complex. We plan to identify proteins that interact with PrPC and/or PrPSc in its native complexes with the aim to clarify the physiological function of PrPc, to identify the molecules chaperoning the conversion of PrPc into PrPSc, and prion neurotoxicity. To isolate the protein complexes that co-precipitate with PrPC and/or PrPSc we are using two different approaches. First, we are utilizing antibodies against defined PrP epitopes which are specifically eluted by distinct epitope mimetic peptides. Second, we are using transgenic mice in which PrPc is fused with a myc tag. This exclusive proteomic tool will allow us to confirm the identified interactors and to avoid the risk of loosing possible interactions that could occur in the same region of antibody-epitope. Those proteins, which will be confirmed in vitro to functionally interact with PrPC and/or PrPSc, will be constitutively or conditionally overexpressed and/or ablated in mice in order to determine their role in mediating PrP function in vivo. At present, genomic approaches alone provide little information with regard to prion biology. Instead, in vivo proteomic approach is an exclusive system to understand the role of functionally distinct conformations of prions in normal and pathological situations, and to clarify if the infectious prion consists of only a conformer of host protein PrPc or if other components are required to generate it or render it infectious. Our discovery that PrP is part of a well-defined multiprotein-complex, and that its dysfunction could be associated with disease, may reveal additional potential therapeutic targets suitable to blocking prion replication and/or neurodegeneration, or modify prion susceptibility. Also, it will be of interest to test whether some components of the complex may serve as surrogate markers of disease. In summary, the proteomic approach combine with mouse genetics will provide insights into the normal and the pathological role of PrP and the results may provide a basis for predictive diagnostics and perhaps even therapeutic treatments. |
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| Keywords / Suchbegriffe | prion diseases, proteomics | ||||
| Project leadership and contacts / Projektleitung und Kontakte |
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| Funding source(s) / Unterstützt durch |
Foundation |
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| Duration of Project / Projektdauer | Jan 2006 to Dec 2008 |