Dynamic Changes in Presynaptic and Axonal Transport Proteins Combined with Striatal Neuroinflammation Precede Dopaminergic Neuronal Loss in a Rat Model of AAV α-Synucleinopathy

Chung, Chee Yeun; Koprich, James B.; Siddiqi, Hasan K.; Isacson, Ole

doi:10.1523/jneurosci.5427-08.2009

Cited by 337 publications

(311 citation statements)

References 32 publications

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“…Specifically, a dying back of neurites was observed in the E57K group (Fig. 2H), resembling the axonal pathology described in PD (24,25). In addition, the neurites contained larger lump-like appearances within the E57K group than in the hWT α-syn (Fig.…”

Section: And E)supporting

confidence: 62%

“…To analyze the distribution and levels of α-syn in the brains of rodents injected with the lentiviral particles, as previously described, samples were lysed and extracts fractioned into soluble and insoluble fractions by ultracentrifugation (25). Twenty micrograms of protein per lane were loaded into 4% to 12% SDS/PAGE gels and blotted onto PVDF membranes.…”

Section: Methodsmentioning

confidence: 99%

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In vivo demonstration that α-synuclein oligomers are toxic

Winner

Jappelli

Maji

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

1,305

1,156

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The aggregation of proteins into oligomers and amyloid fibrils is characteristic of several neurodegenerative diseases, including Parkinson disease (PD). In PD, the process of aggregation of α-synuclein (α-syn) from monomers, via oligomeric intermediates, into amyloid fibrils is considered the disease-causative toxic mechanism. We developed α-syn mutants that promote oligomer or fibril formation and tested the toxicity of these mutants by using a rat lentivirus system to investigate loss of dopaminergic neurons in the substantia nigra. The most severe dopaminergic loss in the substantia nigra is observed in animals with the α-syn variants that form oligomers (i.e., E57K and E35K), whereas the α-syn variants that form fibrils very quickly are less toxic. We show that α-syn oligomers are toxic in vivo and that α-syn oligomers might interact with and potentially disrupt membranes. P arkinson disease (PD) is the most common movement disorder, currently affecting approximately 2% of the population older than age 60 y. Prominent neuropathological hallmarks of PD are the loss of dopaminergic neurons in the substantia nigra (SN) region of the midbrain (1) and the presence of α-syn-containing intracellular inclusions: Lewy bodies (LBs) and Lewy neurites (2). α-Syn, a 140-aa protein physiologically found in presynaptic terminals of neurons, is the major fibrillar protein in LBs and Lewy neurites in sporadic and inherited PD. Moreover, point mutations (A53T, A30P, E46K) and gene multiplications of human WT (hWT) α-syn are related to rare familial autosomal-dominant forms of early-onset PD (3-6), suggesting that increased gene dosage and aberrant protein structure may accelerate disease onset and progression.Recent reports indicate that the accumulation of α-syn can result in the formation of intermediate-state oligomers, and oligomers of different shapes and sizes have been described (7-10). These oligomers interact with lipids, disrupt membranes (7,8), and cause cell death in vitro (10, 11) and in nonmammalian models, such as Caenorhabditis elegans and Drosophila melanogaster (12). However, we are aware of no previous direct in vivo demonstration of the toxicity of α-syn oligomers in mammals.We aim to establish a model that allows specific testing of the effects of α-syn oligomerization in vitro and in vivo. To elucidate the causal structure-toxicity relationship of these oligomeric protein assemblies in a mammalian system, we designed "conformation-trapped" mutants based on structural modeling of α-syn fibrils (13, 14). Structurally, amyloid fibrils of α-syn are composed of cross-β-sheets (15). Residues from approximately 30 to 110 of α-syn form the core of the fibrils, whereas the approximately 30 N-terminal residues are heterogeneous and the approximately 30 C-terminal residues are flexible (13,14,16,17). Based on our structural model, recently developed from NMR data, the core of α-syn fibrils comprises five β-strands reminiscent of a five-layered "β-sandwich" (14). Several loops adjacent to and between the strands ar...

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Section: And E)supporting

confidence: 62%

Section: Methodsmentioning

confidence: 99%

In vivo demonstration that α-synuclein oligomers are toxic

Winner

Jappelli

Maji

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

1,305

1,156

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“…Lentiviral vectors expressing human wild type or mutant forms of α-synuclein have been shown to lead to a progressive loss of nigral dopaminergic neurons by 24-35% in rats over 5 months 37 whereas adenoviruses expressing human α-synuclein have been shown to decrease nigral dopaminergic neurons by up to 80% in as short as 6 weeks, however these results are less consistent. 11,12,[38][39][40][41] In our model, miR-7T-AsRed significantly reduced TH expression by one-third at week 16 and two thirds at week 24. However, staining with VMAT2, another neuronal marker showed that there was only a 30% loss of neurons at 24 weeks suggesting that the nigral neurons had downregulated their activity.…”

Section: Discussionmentioning

confidence: 55%

Loss of MicroRNA-7 Regulation Leads to α-Synuclein Accumulation and Dopaminergic Neuronal Loss In Vivo

et al. 2017

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms show that miR-7 is decreased in the substantia nigra of patients with PD and therefore may play an essential role in the regulation of α-synuclein expression. Furthermore, we have found that lentiviral mediated expression of miR-7 complementary binding sites to stably induce a loss of miR-7 function results in an increase in α-synuclein expression in vitro and in vivo. We have also shown that depletion of miR-7 using a miR-decoy produces a loss of nigral dopaminergic neurons accompanied by a reduction of striatal dopamine content. These data suggest that miR-7 has an important role in the regulation of α-synuclein and dopamine physiology and may provide a new paradigm to study the pathology of PD.3

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“…2, more than 70% of TH-positive neurons were GFP-positive 4 weeks after AAV injection into the SN, indicating efficient expression in DA neurons. It has been demonstrated that AAV-mediated ␣-synuclein delivery into the SN resulted in DA neuronal degeneration in both rat and mouse PD models (43,44). Transgenic mice overexpressing amino acid residues 1-130 of human ␣-synuclein developed selective dopaminergic neuronal loss in the substantia nigra pars compacta (45).…”

Section: ␣-Synuclein Cleavage By Mmp3mentioning

confidence: 99%

Role of Matrix Metalloproteinase 3-mediated α-Synuclein Cleavage in Dopaminergic Cell Death

Choi

Kim

et al. 2011

Journal of Biological Chemistry

100

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Evidence suggests that the C-terminal truncation of ␣-synuclein is equally important as aggregation of ␣-synuclein in Parkinson disease (PD). Our previous results showed that an endopeptidase, matrix metalloproteinase-3 (MMP3), was induced and activated in dopaminergic (DA) cells upon stress conditions. Here, we report that MMP3 cleaved ␣-synuclein in vitro and in vivo and that ␣-synuclein and MMP3 were co-localized in Lewy bodies (LB) in the postmortem brains of PD patients. Incubation of ␣-synuclein with the catalytic domain of MMP3 (cMMP3) resulted in generation of several peptides, and the peptide profiles of WT ␣-synuclein (WTsyn) and A53T mutant (A53Tsyn) were different. Combined analysis using mass spectrometry and N-terminal determination revealed that MMP3 generated C-terminally truncated peptides of amino acids 1-78, 1-91, and 1-93 and that A53Tsyn produced significantly higher quantities of these peptides. Similar sizes of peptides were detected in N27 DA cells under oxidative stress and RNA interference to knock down MMP3-attenuated peptide generation. Co-overexpression of cMMP3 with either WTsyn or A53Tsyn led to a reduction in Triton X-100-insoluble aggregates and an increase in protofibril-like small aggregates. In addition, overexpression of the 1-93-amino acid peptide in the substantia nigra led to DA neuronal loss without LB-like aggregate formation. The results strongly indicate that MMP3 digestion of ␣-synuclein in DA neurons plays a pivotal role in the progression of PD through modulation of ␣-synuclein in aggregation, LB formation, and neurotoxicity.The epidemiological as well as animal studies suggest that environmental factors, genetic predispositions, and the interplay between the two factors are implicated in the PD 3 pathogenesis (1), although the underlying molecular mechanisms remain largely unknown. ␣-Synuclein is a major component of Lewy bodies (LB), the pathological hallmark of Parkinson disease (2). As expression of three mutant forms of ␣-synuclein, A53T, A30P, and E46K, in the brain (3-5) and increased copy number by duplication or triplication of the wild-type ␣-synuclein gene (6 -8) have been reported in the early onset familial cases of PD, the pathophysiological role of these mutants of ␣-synuclein has been a target of extensive investigations in PD research. The ability of ␣-synuclein to aggregate and form fibrillar deposits has been shown to play a central role in its pathology. The facts that the presence of C-terminally truncated ␣-synuclein in LB of sporadic PD and LB dementia (9, 10), the existence of various lengths of the truncated forms of ␣-synuclein in brain (10, 11), and the formation of C-terminally truncated ␣-synuclein in A53T transgenic mice that show motor symptoms (12) implicate the probable involvement of endopeptidases in cleaving ␣-synuclein in brains. In addition, about 15% of ␣-synuclein in LB are truncated forms, and incomplete degradation of ␣-synuclein produced highly amyloidogenic fragments (9, 13). Recent reports showed that matrix metalloprotei...

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Dynamic Changes in Presynaptic and Axonal Transport Proteins Combined with Striatal Neuroinflammation Precede Dopaminergic Neuronal Loss in a Rat Model of AAV α-Synucleinopathy

Cited by 337 publications

References 32 publications

In vivo demonstration that α-synuclein oligomers are toxic

In vivo demonstration that α-synuclein oligomers are toxic

Loss of MicroRNA-7 Regulation Leads to α-Synuclein Accumulation and Dopaminergic Neuronal Loss In Vivo

Role of Matrix Metalloproteinase 3-mediated α-Synuclein Cleavage in Dopaminergic Cell Death

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