The long-term objective of this Program Project is to advance the understanding of the pathogenic process in prion diseases, with a special focus on elucidating the mechanisms by which these diseases are transmitted. The major specific goals are: (i) Determine structural mechanisms of prion protein conformational conversion and prion propagation;(ii) Advance molecular level understanding of prion strains and transmissibility barriers;(iii) Elucidate molecular and structural determinants that control transmissibility and phenotypic variability of familial and atypical forms of human prion diseases. Answers to questions addressed in this research are of fundamental importance for understanding the pathogenic process and from a more practical perspective of pharmacological intervention and public health safety. The Program has been structured into three integrated and interactive Research Projects supported by three Cores. Each individual Research Project addresses different, yet closely related, aspects of the overall goals, approaching them using different experimental tools and at different levels of organization and complexity. The main focus of Research Project 1 is on elucidating the structural basis of prion protein conversion and the structure of the infectious PrPSc conformer. This Project also seeks to identify specific structura differences in PrPSc that underlie phenotypic variability of human prion diseases. Research Project 2 focuses on issues related to prion strains and transmissibility barriers as well as prion therapy. Using PMCA technology, structural studies and bioassays, this Project seeks to (i) elucidate the mechanisms involved in controlling barriers for prion transmissibility from animals to humans;(ii) explore the mechanism by which the specific environment of different organs affects the selection of prion strains and their replication potential;(iii) develop a novel therapeutic strategy in prion disease. The focus of Research Project 3 is on human prion diseases, seeking to (i) develop better understanding of mechanisms controlling phenotypic variability of these disorders;(ii) understand the role of prion protein glycosylation in some fors of these diseases and (iii) elucidating the biochemical and structural basis of large differences i transmissibility between different forms of human prion diseases (in collaboration with Project 1). Each of these three Research Projects will be supported by the Administrative, Animal and Neuropathology Cores that will provide common services with regard to research administration and coordination, all aspects of animal studies, and preparation and neuropathological characterization of animal and human tissue.
Transmissible spongiform encephalopathies, or prion diseases, are neurodegenerative disorders that can be transmitted from animals to humans. Understanding the pathogenic process in these disorders and the mechanisms by which they are transmitted within and between species is of fundamental importance for protecting the human population as well for the development of therapeutic strategies. Project 1: Molecular and Structural Basis of Prion Protein Conversion to the Infectious Form Project Leader: Witold Surewicz DESCRIPTION (as provided by applicant): The main focus of Research Project 1 is to elucidate the structural basis of prion protein conversion and the structure of the infectious PrPSc conformer. This Project also seeks to identify specific structural differences in PrPSc that underlie phenotypic variability of human prion diseases. This contributes to the over-arching objective of the Program Project to advance the understanding of the pathogenic process in prion diseases, with a special focus on the mechanisms of disease transmission. A critical gap in TSE research is limited understanding of the structure of PrPSc. This knowledge is fundamental to understanding the mechanism of prion replication. Here we address this issue by a number of complementary approaches, ranging from studies with apparently infectious amyloid fibrils formed by fragment(s) of PrP to structural characterization of highly infectious prions generated from the recombinant full-length PrP and determination of lower-resolution strain-specific structural constraints for brain-derived PrPSc. We anticipate that at the very least, these studies will allow us to (i) identify and characterize the critical seedin element in prion protein conversion to the infectious form, both with regard to its sequence as well as high-resolution structure;(ii) conclusively establish the overall folding motif within the-core of infectious PrPres aggregates (thereby resolving the major controversy in the field) and determine the identity of individual - strands and turns between them;(iii) determine which specific structural features are critical determinants of prion infectivity and use this informatio to advance the development of novel therapeutic strategy based on the concept of self-propagating antiprions.