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Proteome analysis reveals roles of L-DOPA in response to oxidative stress in neurons.

Jami MS, Pal R, Hoedt E, Neubert TA, Larsen JP, Møller SG - BMC Neurosci (2014)

Bottom Line: We observed that oxidative stress affects metabolic pathways as well as cytoskeletal integrity and that neuronal cells respond to oxidative conditions by enhancing numerous survival pathways.Oxidative stress changes neuronal metabolic routes and affects cytoskeletal integrity.Further, L-DOPA appears to reverse some H2O2-mediated effects evident at both the proteome and cellular level.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, St John's University, New York, NY, USA. mollers@stjohns.edu.

ABSTRACT

Background: Parkinson's disease (PD) is the second most common neurodegenerative movement disorder, caused by preferential dopaminergic neuronal cell death in the substantia nigra, a process also influenced by oxidative stress. L-3,4-dihydroxyphenylalanine (L-DOPA) represents the main treatment route for motor symptoms associated with PD however, its exact mode of action remains unclear. A spectrum of conflicting data suggests that L-DOPA may damage dopaminergic neurons due to oxidative stress whilst other data suggest that L-DOPA itself may induce low levels of oxidative stress, which in turn stimulates endogenous antioxidant mechanisms and neuroprotection.

Results: In this study we performed a two-dimensional gel electrophoresis (2DE)-based proteomic study to gain further insight into the mechanism by which L-DOPA can influence the toxic effects of H2O2 in neuronal cells. We observed that oxidative stress affects metabolic pathways as well as cytoskeletal integrity and that neuronal cells respond to oxidative conditions by enhancing numerous survival pathways. Our study underlines the complex nature of L-DOPA in PD and sheds light on the interplay between oxidative stress and L-DOPA.

Conclusions: Oxidative stress changes neuronal metabolic routes and affects cytoskeletal integrity. Further, L-DOPA appears to reverse some H2O2-mediated effects evident at both the proteome and cellular level.

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Related in: MedlinePlus

Comparison of the proteomes of SH-SY5Y cells with or without H2O2. Representative 2-DE gels (n = 3 for each treatment) of the proteomes of SH-SY5Y cells grown for 8 hours in the (A) absence or (B) presence of 2 mM H2O2. The uppercase letters are used for those spots overrepresented in each condition whereas lowercase letters are used for spots underrepresented. The spots differentially represented are numbered and correspond to the proteins listed in Table 2.
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Fig2: Comparison of the proteomes of SH-SY5Y cells with or without H2O2. Representative 2-DE gels (n = 3 for each treatment) of the proteomes of SH-SY5Y cells grown for 8 hours in the (A) absence or (B) presence of 2 mM H2O2. The uppercase letters are used for those spots overrepresented in each condition whereas lowercase letters are used for spots underrepresented. The spots differentially represented are numbered and correspond to the proteins listed in Table 2.

Mentions: Based on these findings we then performed a set of proteomic analyses on SH-SY5Y cells exposed to the same treatments as described above. The first experiment focused on the effects of H2O2 on the neuronal proteome where we compared the proteome profile of SH-SY5Y cells under control condition (Table 1; Condition A, Figure 2A) to cells treated with H2O2 (Table 1; Condition B, Figure 2B). In this experiment we observed significant up-regulation of ten proteins (spots 1–10) and significant down-regulation of six proteins (spots 11–16) compared to control condition (Table 1). In a second experiment we compared the proteome profile of cells exposed to L-DOPA (Table 1; Condition C, Figure 3A) to control cells and found one detectable protein (spot 17) that changes in response to L-DOPA exposure (Table 2). Finally, in a third experiment we compared the proteome profile from cells exposed to both H2O2 and L-DOPA (Figure 3B; Condition D) to control cells (Figure 2A; Condition A) and observed up-regulation of five proteins (spots 7–10) and down-regulation of four proteins (spot 14–16 and 18). Interestingly in this comparison spot 17 was detected in response to co-treatment with both H2O2 and L-DOPA but not in the control (Figures 2 and 3). Although L-DOPA can auto-oxidize we did not include catalase in these experiments as our findings show that L-DOPA treatment can reverse the decreased cell viability in response to oxidative stress suggesting the presence of the active form of L-DOPA in our experimental conditions. Detailed information on the number of spots detected in each gel is summarized in Table 1.Table 1


Proteome analysis reveals roles of L-DOPA in response to oxidative stress in neurons.

Jami MS, Pal R, Hoedt E, Neubert TA, Larsen JP, Møller SG - BMC Neurosci (2014)

Comparison of the proteomes of SH-SY5Y cells with or without H2O2. Representative 2-DE gels (n = 3 for each treatment) of the proteomes of SH-SY5Y cells grown for 8 hours in the (A) absence or (B) presence of 2 mM H2O2. The uppercase letters are used for those spots overrepresented in each condition whereas lowercase letters are used for spots underrepresented. The spots differentially represented are numbered and correspond to the proteins listed in Table 2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4125692&req=5

Fig2: Comparison of the proteomes of SH-SY5Y cells with or without H2O2. Representative 2-DE gels (n = 3 for each treatment) of the proteomes of SH-SY5Y cells grown for 8 hours in the (A) absence or (B) presence of 2 mM H2O2. The uppercase letters are used for those spots overrepresented in each condition whereas lowercase letters are used for spots underrepresented. The spots differentially represented are numbered and correspond to the proteins listed in Table 2.
Mentions: Based on these findings we then performed a set of proteomic analyses on SH-SY5Y cells exposed to the same treatments as described above. The first experiment focused on the effects of H2O2 on the neuronal proteome where we compared the proteome profile of SH-SY5Y cells under control condition (Table 1; Condition A, Figure 2A) to cells treated with H2O2 (Table 1; Condition B, Figure 2B). In this experiment we observed significant up-regulation of ten proteins (spots 1–10) and significant down-regulation of six proteins (spots 11–16) compared to control condition (Table 1). In a second experiment we compared the proteome profile of cells exposed to L-DOPA (Table 1; Condition C, Figure 3A) to control cells and found one detectable protein (spot 17) that changes in response to L-DOPA exposure (Table 2). Finally, in a third experiment we compared the proteome profile from cells exposed to both H2O2 and L-DOPA (Figure 3B; Condition D) to control cells (Figure 2A; Condition A) and observed up-regulation of five proteins (spots 7–10) and down-regulation of four proteins (spot 14–16 and 18). Interestingly in this comparison spot 17 was detected in response to co-treatment with both H2O2 and L-DOPA but not in the control (Figures 2 and 3). Although L-DOPA can auto-oxidize we did not include catalase in these experiments as our findings show that L-DOPA treatment can reverse the decreased cell viability in response to oxidative stress suggesting the presence of the active form of L-DOPA in our experimental conditions. Detailed information on the number of spots detected in each gel is summarized in Table 1.Table 1

Bottom Line: We observed that oxidative stress affects metabolic pathways as well as cytoskeletal integrity and that neuronal cells respond to oxidative conditions by enhancing numerous survival pathways.Oxidative stress changes neuronal metabolic routes and affects cytoskeletal integrity.Further, L-DOPA appears to reverse some H2O2-mediated effects evident at both the proteome and cellular level.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, St John's University, New York, NY, USA. mollers@stjohns.edu.

ABSTRACT

Background: Parkinson's disease (PD) is the second most common neurodegenerative movement disorder, caused by preferential dopaminergic neuronal cell death in the substantia nigra, a process also influenced by oxidative stress. L-3,4-dihydroxyphenylalanine (L-DOPA) represents the main treatment route for motor symptoms associated with PD however, its exact mode of action remains unclear. A spectrum of conflicting data suggests that L-DOPA may damage dopaminergic neurons due to oxidative stress whilst other data suggest that L-DOPA itself may induce low levels of oxidative stress, which in turn stimulates endogenous antioxidant mechanisms and neuroprotection.

Results: In this study we performed a two-dimensional gel electrophoresis (2DE)-based proteomic study to gain further insight into the mechanism by which L-DOPA can influence the toxic effects of H2O2 in neuronal cells. We observed that oxidative stress affects metabolic pathways as well as cytoskeletal integrity and that neuronal cells respond to oxidative conditions by enhancing numerous survival pathways. Our study underlines the complex nature of L-DOPA in PD and sheds light on the interplay between oxidative stress and L-DOPA.

Conclusions: Oxidative stress changes neuronal metabolic routes and affects cytoskeletal integrity. Further, L-DOPA appears to reverse some H2O2-mediated effects evident at both the proteome and cellular level.

Show MeSH
Related in: MedlinePlus