The prion concept and synthetic prions

Transmissible spongiform encephalopathies or prion diseases are a group of fatal neurodegenerative diseases caused by unconventional infectious agents, known as prions (PrPSc). Prions derive from a conformational conversion of the normally folded prion protein (PrPC), which acquires pathological and infectious features. Moreover, PrPSc is able to transmit the pathological conformation to PrPC through a mechanism that is still not well understood. The generation of synthetic prions, which behave like natural prions, is of fundamental importance to study the process of PrPC conversion and to assess the efficacy of therapeutic strategies to interfere with this process. Moreover, the ability of synthetic prions to induce pathology in animals confirms that the pathological properties of the prion strains are all enciphered in abnormal conformations, characterizing these infectious agents.