[Recent progress and future direction of neurodegenerative disease research]

Although the pathogenetic mechanisms underlying neurodegenerative diseases have been long elusive, recent progress in molecular neurogenetics and neurobiology has suggested that accumulation of misfolded protein leads to dysfunction and degeneration of neurons. Misfolded proteins have propensities to form fibrils termed amyloid fibrils. In the process of amyloid fibrils, intermediate forms such as oligomers and protofibrils are produced and thought to have cytotoxic effects to neurons. Neurotoxicity mediated by misfolded proteins are also caused by stress response such as unfolded protein response. Moreover, recent findings indicate that nonneuronal cells surrounding neurons or extracellular misfolded proteins promote neurodegeneration. To eliminate toxic proteins would constitute promising future therapy for neurodegenerative disorders.