Transmissible spongiform encephalopathies and prion protein interconversions

Abstract

This chapter discusses important natural human and animal transmissible spongiform encephalopathies (TSE) diseases and various experimental models. It also summarizes prion protein (PrP) biochemistry and cell biology, especially as it relates to the TSE-associated conversion of PrPc to PrP-res. TSE diseases, or prion diseases, are rare, fatal neurodegenerative diseases of humans and other animals. They are transmissible by inoculation or ingestion of infected tissues. Their primary symptoms in humans are dementia and ataxia. These diseases are usually characterized by spongiform degeneration of the brain, accompanied by the appearance of activated astrocytes. Most distinctive, however, is the accumulation of abnormal protease-resistant forms of host-derived PrP in the central nervous system and, to a lesser extent, in lymphoreticular tissues. Much evidence suggests that abnormal forms of PrP of some sort are critical in the transmission and pathogenesis of TSE diseases. TSE diseases in humans can be divided into three groups—namely, sporadic, familial, and iatrogenic. Familial TSE diseases are all associated with different mutations in the PrP gene and include familial Creutzfeldt–Jakob disease, Gerstmann–Sträussler–Scheinker syndrome, and fatal familial insomnia.