Transgenic overexpression of the alpha-synuclein interacting protein synphilin-1 leads to behavioral and neuropathological alterations in mice.

in Neurogenetics (2010), 11(1), 107-20

Synphilin-1 has been identified as an interacting protein of alpha-synuclein, Parkin, and LRRK2, proteins which are mutated in familial forms of Parkinson disease (PD). Subsequently, synphilin-1 has also ... [more ▼]

Synphilin-1 has been identified as an interacting protein of alpha-synuclein, Parkin, and LRRK2, proteins which are mutated in familial forms of Parkinson disease (PD). Subsequently, synphilin-1 has also been shown to be an intrinsic component of Lewy bodies in sporadic PD. In order to elucidate the role of synphilin-1 in the pathogenesis of PD, we generated transgenic mice overexpressing wild-type and mutant (R621C) synphilin-1 driven by a mouse prion protein promoter. Transgenic expression of both wild-type and the R621C variant synphilin-1 resulted in increased dopamine levels of the nigrostriatal system in 3-month-old mice. Furthermore, we found pathological ubiquitin-positive inclusions in cerebellar sections and dark-cell degeneration of Purkinje cells. Both transgenic mouse lines showed significant reduction of motor skill learning and motor performance. These findings suggest a pathological role of overexpressed synphilin-1 in vivo and will help to further elucidate the mechanisms of protein aggregation and neuronal cell death. [less ▲]

Loss of function mutations in the gene encoding Omi/HtrA2 in Parkinson's disease.

in Human molecular genetics (2005), 14(15), 2099-111

Recently targeted disruption of Omi/HtrA2 has been found to cause neurodegeneration and a parkinsonian phenotype in mice. Using a candidate gene approach, we performed a mutation screening of the Omi ... [more ▼]

Recently targeted disruption of Omi/HtrA2 has been found to cause neurodegeneration and a parkinsonian phenotype in mice. Using a candidate gene approach, we performed a mutation screening of the Omi/HtrA2 gene in German Parkinson's disease (PD) patients. In four patients, we identified a novel heterozygous G399S mutation, which was absent in healthy controls. Moreover, we identified a novel A141S polymorphism that was associated with PD (P<0.05). Both mutations resulted in defective activation of the protease activity of Omi/HtrA2. Immunohistochemistry and functional analysis in stably transfected cells revealed that S399 mutant Omi/HtrA2 and to a lesser extent, the risk allele of the A141S polymorphism induced mitochondrial dysfunction associated with altered mitochondrial morphology. Cells overexpressing S399 mutant Omi/HtrA2 were more susceptible to stress-induced cell death than wild-type. On the basis of functional genomics, our results provide a novel link between mitochondrial dysfunction and neurodegeneration in PD. [less ▲]