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Mechanisms of aluminium neurotoxicity in oxidative stress-induced ...

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Contribution <strong>of</strong> <strong>oxidative</strong> and nitrosative <strong>stress</strong> to PD pathogenesis<br />

INTRODUCTION<br />

As we have previously seen, genes l<strong>in</strong>ked to familial PD are important <strong>in</strong><br />

mitochondrial function or <strong>in</strong> the handl<strong>in</strong>g <strong>of</strong> misfolded prote<strong>in</strong>s (Abou-Sleiman et al.<br />

2006, Savitt et al. 2006, Sulzer 2007). Besides, <strong>oxidative</strong> and nitrosative <strong>stress</strong> had a<br />

significant effect on the normal function <strong>of</strong> familial PD-related gene products <strong>in</strong> the<br />

process <strong>of</strong> neurodegeneration.<br />

Figure 19: Generation <strong>of</strong> ROS and RNS <strong>in</strong> SNpc neuron (Tsang and Chung 2009)<br />

Oxidative <strong>stress</strong> is known to promote prote<strong>in</strong> misfold<strong>in</strong>g and aggregation. For<br />

example, α-synucle<strong>in</strong> can undergo <strong>oxidative</strong> modifications such as the addition <strong>of</strong> a DA<br />

adduct on α-synucle<strong>in</strong> (Conway et al. 2001). This modification stabilizes the toxic α-<br />

synucle<strong>in</strong> prot<strong>of</strong>ibrils and makes it resistant to chaperone mediated autophagy (CMA)<br />

lead<strong>in</strong>g to a complete blockade <strong>of</strong> other prote<strong>in</strong>s degradation via this pathwaw<br />

(Mart<strong>in</strong>ez-Vicente et al. 2008). As well, α-synucle<strong>in</strong> prot<strong>of</strong>ibrils can permeabilize<br />

synaptic vesicles (Volles et al. 2001, Mazzulli et al. 2006, Mosharov et al. 2006) lead<strong>in</strong>g<br />

to an <strong>in</strong>crease <strong>of</strong> more α-synucle<strong>in</strong> prot<strong>of</strong>ibrils. Nitrosative modifications <strong>of</strong> α-synucle<strong>in</strong><br />

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