Folding, Misfolding and Therapeutics in Prion Diseases

Prion diseases are rare neurodegenerative disorders affecting humans and other animals, caused by a proteinaceous infectious agent named prion. The pivotal event in these pathologies is the conversion of PrPC, a physiologically expressed protein of poorly characterized function, into a misfolded conformer, named PrPSc, which is capable of replicating its conformationally-encoded information by inducing the conversion of its physiological counterpart. The aggregates resulting from this misfolding process accumulate in the central nervous system of affected organisms leading to neuronal death. Prion diseases are always fatal and no therapy is currently available. The lack of an effective therapeutic strategy to tackle such conditions is the result of the poor available information regarding many aspects of PrPSc, such as its structure, pathogenicity, and its replication mechanism. To complicate things further, PrPSc can appear as a set of distinct conformers, named strains, characterized by the capacity to evolve through modification and selection of their conformations, promoting resistance to treatments. In this work, we focus on two main aspects of prion biology, the elucidation of prion structure and propagation, and the development of a novel pharmacological strategy to tackle prion diseases. In both projects, we exploited the potential of integrative schemes combining computational methods and experimental data. Such approaches allowed us to build a plausible atomistic model of PrPSc and to propose a propagation mechanism describing the series of events underlying prion propagation. Moreover, the application of advanced computational schemes enabled us to identify a PrP folding intermediate displaying unique druggability properties. By exploiting the structural information of this protein conformer we identified a compound capable of acting as a pharmacological degrader for PrP by interfering with its folding pathway. Overall, this work highlights how the integration of computational and experimental methods is an extremely valuable scheme to answer complex biological questions, such as unraveling the mechanisms of protein misfolding and providing the tools to design pharmacological strategies for untreatable diseases.