1. |
|
|
2. |
- Xilouri, Maria, et al.
(author)
-
Boosting chaperone-mediated autophagy in vivo mitigates alpha-synuclein-induced neurodegeneration
- 2013
-
In: Brain. - : Oxford University Press (OUP). - 1460-2156 .- 0006-8950. ; 136, s. 2130-2146
-
Journal article (peer-reviewed)abstract
- alpha-Synuclein levels are critical to Parkinson's disease pathogenesis. Wild-type alpha-synuclein is degraded partly by chaperone-mediated autophagy, and aberrant alpha-synuclein may act as an inhibitor of the pathway. To address whether the induction of chaperone-mediated autophagy may represent a potential therapy against alpha-synuclein-induced neurotoxicity, we overexpressed lysosomal-associated membrane protein 2a, the rate-limiting step of chaperone-mediated autophagy, in human neuroblastoma SH-SY5Y cells, rat primary cortical neurons in vitro, and nigral dopaminergic neurons in vivo. Overexpression of the lysosomal-associated membrane protein 2a in cellular systems led to upregulation of chaperone-mediated autophagy, decreased alpha-synuclein turnover, and selective protection against adenoviral-mediated wild-type alpha-synuclein neurotoxicity. Protection was observed even when the steady-state levels of alpha-synuclein were unchanged, suggesting that it occurred through the attenuation of alpha-synuclein-mediated dysfunction of chaperone-mediated autophagy. Overexpression of the lysosomal receptor through the nigral injection of recombinant adeno-associated virus vectors effectively ameliorated alpha-synuclein-induced dopaminergic neurodegeneration by increasing the survival of neurons located in the substantia nigra as well as the axon terminals located in the striatum, which was associated with a reduction in total alpha-synuclein levels and related aberrant species. We conclude that induction of chaperone-mediated autophagy may provide a novel therapeutic strategy in Parkinson's disease and related synucleinopathies through two different mechanisms: amelioration of dysfunction of chaperone-mediated autophagy and lowering of alpha-synuclein levels.
|
|
3. |
- Xilouri, Maria, et al.
(author)
-
LAMP2A as a therapeutic target in Parkinson disease
- 2013
-
In: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 9:12, s. 2166-2168
-
Journal article (other academic/artistic)abstract
- Abnormal aggregation of SNCA/-synuclein plays a crucial role in Parkinson disease (PD) pathogenesis. SNCA levels determine its toxicity, and its accumulation, even to a small extent, may be a risk factor for neurodegeneration. One of the main pathways for SNCA degradation is chaperone-mediated autophagy (CMA), a selective form of autophagy, while aberrant SNCA may act as a CMA inhibitor. In the current punctum we summarize our recent data showing that induction of CMA, via overexpression of the protein controlling its rate-limiting step, the lysosomal receptor LAMP2A, effectively decreases SNCA levels and ameliorates SNCA-induced neurodegeneration, both in neuronal cell culture systems and in the rat brain. Such findings suggest that modulation of LAMP2A and, consequently, CMA, represents a viable therapeutic target for PD and other synucleinopathies where SNCA accumulation and aggregation plays a fundamental role.
|
|
4. |
- Xilouri, Maria, et al.
(author)
-
Selective neuroprotective effects of the S18Y polymorphic variant of UCH-L1 in the dopaminergic system
- 2012
-
In: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 21:4, s. 874-889
-
Journal article (peer-reviewed)abstract
- Genetic studies have implicated the neuronal ubiquitin C-terminal hydrolase (UCH) protein UCH-L1 in Parkinson's disease (PD) pathogenesis. Moreover, the function of UCH-L1 may be lost in the brains of PD and Alzheimer's disease patients. We have previously reported that the UCH-L1 polymorphic variant S18Y, potentially protective against PD in population studies, demonstrates specific antioxidant functions in cell culture. Albeit genetic, biochemical and neuropathological data support an association between UCH-L1, PD, synaptic degeneration and oxidative stress, the relationship between the dopaminergic system and UCH-L1 status remains obscure. In the current study, we have examined the dopaminergic system of mice lacking endogenous UCH-L1 protein (gracile axonal dystrophy mice). Our findings show that the lack of wild-type (WT) UCH-L1 does not influence to any significant degree the dopaminergic system at baseline or following injections of the neurotoxin methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Furthermore, using a novel intrastriatal adenoviral injection protocol, we have found that mouse nigral neurons retrogradely transduced with S18Y UCH-L1, but not the WT protein, are significantly protected against MPTP toxicity. Overall, these data provide evidence for an antioxidant and neuroprotective effect of the S18Y variant of UCH-L1, but not of the WT protein, in the dopaminergic system, and may have implications for the pathogenesis of PD or related neurodegenerative conditions, in which oxidative stress might play a role.
|
|