Transgenic Models of ?-Synuclein Pathology
Accumulation and toxic conversion to protofibrils of ?-synuclein has been associated with neurological disorders such as Parkinson's disease (PD), Lewy body disease, multiple system atrophy, neurodegeneration with brain iron accumulation type 1, and Alzheimer's disease. In recent years, modeling these disorders in transgenic (tg) mice and flies has helped improve understanding of the pathogenesis of these diseases and has established the basis for the development of new experimental treatments. Overexpression of ?-synuclein in tg mice in a region- and cell-specific manner results in degeneration of selective circuitries accompanied by motor deficits and inclusion formation similar to what is found in PD and related disorders. Furthermore, studies in singly and doubly tg mice have shown that toxic conversion and accumulation can be accelerated by ?-synuclein mutations associated with familial parkinsonism, by amyloid ? peptide 142 (A? 142), and by oxidative stress. In contrast, molecular chaperones such as Hsp70 and close homologues such as ?-synuclein have been shown to suppress toxicity. Similar studies are underway to evaluate the effects of other modifying genes that might play a role in ?-synuclein ubiquitination. Among them considerable interest has been placed on the role of molecules associated with familial parkinsonism (Parkin, UCHL-1). Furthermore, studying the targeted overexpression of ?-synuclein and other modifier genes in the nigrostriatal and limbic system by using regulatable promoters, lentiviral vectors, and siRNA will help improve understanding of the molecular mechanisms involved in selective neuronal vulnerability, and it will aid the development of new treatments.
transgenic models ?-synclein