Differential neuropathological alterations in transgenic mice expressing alpha-synuclein from the platelet-derived growth factor and Thy-1 promoters.

Accumulation of alpha-synuclein has been associated with neurodegenerative disorders, such as Lewy body disease and multiple system atrophy. We previously showed that expression of wild-type human alpha-synuclein in transgenic mice results in motor and dopaminergic deficits associated with inclusion formation. To determine whether different levels of human alpha-synuclein expression from distinct promoters might result in neuropathology mimicking other synucleopathies, we compared patterns of human alpha-synuclein accumulation in the brains of transgenic mice expressing this molecule from the murine Thy-1 and platelet-derived growth factor (PDGF) promoters. In murine Thy-1-human alpha-synuclein transgenic mice, this protein accumulated in synapses and neurons throughout the brain, including the thalamus, basal ganglia, substantia nigra, and brainstem. Expression of human alpha-synuclein from the PDGF promoter resulted in accumulation in synapses of the neocortex, limbic system, and olfactory regions as well as formation of inclusion bodies in neurons in deeper layers of the neocortex. Furthermore, one of the intermediate expressor lines (line M) displayed human alpha-synuclein expression in glial cells mimicking some features of multiple system atrophy. These results show a more widespread accumulation of human alpha-synuclein in transgenic mouse brains. Taken together, these studies support the contention that human alpha-synuclein expression in transgenic mice might mimic some neuropathological alterations observed in Lewy body disease and other synucleopathies, such as multiple system atrophy.

Rockenstein E ，Mallory M ，Hashimoto M ，Song D ，Shults CW ，Lang I ，Masliah E ... -  《JOURNAL OF NEUROSCIENCE RESEARCH》

Lack of nigral pathology in transgenic mice expressing human alpha-synuclein driven by the tyrosine hydroxylase promoter.

alpha-Synuclein has been identified as a major component of Lewy body inclusions, which are one of the pathologic hallmarks of idiopathic Parkinson's disease. Mutations in alpha-synuclein have been found to be responsible for rare familial cases of Parkinsonism. To test whether overexpression of human alpha-synuclein leads to inclusion formation and neuronal loss of dopaminergic cells in the substantia nigra, we made transgenic mice in which the expression of wild-type or mutant (A30P and A53T) human alpha-synuclein protein was driven by the promoter from the tyrosine hydroxylase gene. Even though high levels of human alpha-synuclein accumulated in dopaminergic cell bodies, Lewy-type-positive inclusions did not develop in the nigrostriatal system. In addition, the number of nigral neurons and the levels of striatal dopamine were unchanged relative to non-transgenic littermates, in mice up to one year of age. These findings suggest that overexpression of alpha-synuclein within nigrostriatal dopaminergic neurons is not in itself sufficient to cause aggregation into Lewy body-like inclusions, nor does it trigger overt neurodegenerative changes.

Matsuoka Y ，Vila M ，Lincoln S ，McCormack A ，Picciano M ，LaFrancois J ，Yu X ，Dickson D ，Langston WJ ，McGowan E ，Farrer M ，Hardy J ，Duff K ，Przedborski S ，Di Monte DA ... -  《-》

Overexpression of alpha-synuclein in rat substantia nigra results in loss of dopaminergic neurons, phosphorylation of alpha-synuclein and activation of caspase-9: resemblance to pathogenetic changes in Parkinson's disease.

Yamada M ，Iwatsubo T ，Mizuno Y ，Mochizuki H ... -  《JOURNAL OF NEUROCHEMISTRY》

Neuropathological spectrum of synucleinopathies.

Synucleinopathies comprise a diverse group of neurodegenerative proteinopathies that share common pathological lesions composed of aggregates of conformational and posttranslational modifications of alpha-synuclein in selected populations of neurons and glia. Abnormal filamentous aggregates of misfolded alpha-synuclein protein are the major components of Lewy bodies, dystrophic (Lewy) neurites, and the Papp-Lantos filaments in oligodendroglia and neurons in multiple system atrophy linked to degeneration of affected brain regions. The synucleinopathies include (1) Lewy body disorders and dementia with Lewy bodies, (2) multiple system atrophy (MSA), and (3) Hallervorden-Spatz disease. (1) The pathological diagnosis of Lewy body disorders and dementia with Lewy bodies is established by validated consensus criteria based on semiquantitative assessment of subcortical and cortical Lewy bodies as their common hallmarks. They are accompanied by subcortical multisystem degeneration with neuronal loss and gliosis with or without Alzheimer pathologic state. Lewy bodies also occur in numerous other disorders, including pure autonomic failure, neuroaxonal dystrophies, and various amyloidoses and tauopathies. (2) Multiple system atrophy, a sporadic, adult-onset degenerative movement disorder of unknown cause, is characterized by alpha-synuclein-positive glial cytoplasmic and rare neuronal inclusions throughout the central nervous system associated with striatonigral degeneration, olivopontocerebellar atrophy, and involvement of medullar and spinal autonomic nuclei. (3) In neurodegeneration with brain iron accumulation type I, or Hallervorden-Spatz disease, alpha-synuclein is present in axonal spheroids and glial and neuronal inclusions. While the identity of the major components of Lewy bodies suggests that a pathway leading from normal soluble to abnormal misfolded filamentous proteins is central for their pathogenesis, regardless of the primary disorder, there are conformational differences in alpha-synuclein between neuronal and glial aggregates, showing nonuniform mapping for its epitopes. Despite several cellular and transgenic models, it is not clear whether inclusion body formation is an adaptive/neuroprotective or a pathogenic reaction/process generated in response to different, mostly undetermined, functional triggers linked to neurodegeneration.

Jellinger KA 《MOVEMENT DISORDERS》

Enhanced substantia nigra mitochondrial pathology in human alpha-synuclein transgenic mice after treatment with MPTP.

Song DD ，Shults CW ，Sisk A ，Rockenstein E ，Masliah E ... -  《-》