[Development of molecular target based-therapy for prion diseases]

Abstract

Prion diseases, or transmissible spongiform encephalopathies, are fatal, neurodegenerative diseases that include Creutzfeldt-Jacob disease (CJD) in humans, bovine spongiform encephalopathy (BSE) and scrapie in animals. Prion diseases are characterized by the accumulation of a misfolded prion protein, PrPSc, which is made by a posttranslational conformational change of the host-encoded cellular prion protein, PrPC. The process of the conformational change remains enigmatic, but a large number of researches on the therapeutic intervention have been done in experimental models over the past 30 years. Against the background of the occurrence of variant CJD in the UK in the 1990s, which is considered to occur by transmission of the BSE agent and to possibly spread through secondary infection via blood transfusion, the research on the development of therapeutic agents has been accelerated using an increasing number of disease models in animals, cells and in vitro system. Candidate therapeutic targets for prion diseases include the following four factors: the PrPC; the PrPSc; the cellular factors associated with the conversion of PrPC into PrPSc; the cellular factors responsible for the neurodegenerative processes. In this article, recent advances in the therapeutic development for prion diseases on the basis of molecular targeting are reviewed, and its future perspectives are discussed.