Molecular mechanisms of neurodegeneration mediated by dysfunctional subcellular organelles in transmissible spongiform encephalopathies

Transmissible spongiform encephalopathies refer to a group of infectious neurodegenerative diseases with an entirely novel mechanism of transmission and pathophysiology including synaptic damage, dendritic atrophy, vacuolization, and microglial activation. Extensive neuronal loss is the main cause of chronic brain deterioration and fatal outcome of prion diseases. As the final outcome of pathological alterations, neuronal death is a prominent feature of all prion diseases. The mechanisms responsible for prion diseases are not well understood. A more comprehensive understanding of the molecular basis of neuronal damage is essential for the development of an effective therapy for transmissible spongiform encephalopathies and other neurodegenerative diseases sharing similar features. Here, we review the molecular mechanisms of mitochondrial dysfunction and endoplasmic reticulum stress-mediated neuronal death, which play crucial roles in the pathogenisis of prion diseases.