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α-Tocopherol at nanomolar concentration protects PC12 cells from hydrogen peroxide-induced death and modulates protein kinase activities.

Zakharova IO, Sokolova TV, Bayunova LV, Vlasova YA, Rychkova MP, Avrova NF - Int J Mol Sci (2012)

Bottom Line: For the first time, the protective effect of α-tocopherol was shown to depend on its concentration in the nanomolar range (1 nM < 10 nM < 100 nM), if the pre-incubation time was 18 h.Nanomolar and micromolar α-tocopherol decreased the number of PC12 cells in late apoptosis induced by H(2)O(2) to the same extent if pre-incubation time was 18 h.The data obtained suggest that inhibition by α-tocopherol in late stage ERK 1/2 and Akt activation induced by H(2)O(2) in PC12 cells makes contribution to its protective effect, while total inhibition of these enzymes is not protective.

View Article: PubMed Central - PubMed

Affiliation: Department of Comparative Neurochemistry, Institute of Evolutionary Physiology and Biochemistry of Russian Academy of Sciences, Thorez avenue, 44, Saint-Petersburg 194223, Russia; E-Mails: zakhar@iephb.ru (I.O.Z.); sokolt1956@mail.ru (T.V.S.); bayunoval@mail.ru (L.V.B.); yousia@mail.ru (Y.A.V.); involved@mail.ru (M.P.R.).

ABSTRACT
The aim of this work was to compare protective and anti-apoptotic effects of α-tocopherol at nanomolar and micromolar concentrations against 0.2 mM H(2)O(2)-induced toxicity in the PC12 neuronal cell line and to reveal protein kinases that contribute to α-tocopherol protective action. The protection by 100 nM α-tocopherol against H(2)O(2)-induced PC12 cell death was pronounced if the time of pre-incubation with α-tocopherol was 3-18 h. For the first time, the protective effect of α-tocopherol was shown to depend on its concentration in the nanomolar range (1 nM < 10 nM < 100 nM), if the pre-incubation time was 18 h. Nanomolar and micromolar α-tocopherol decreased the number of PC12 cells in late apoptosis induced by H(2)O(2) to the same extent if pre-incubation time was 18 h. Immunoblotting data showed that α-tocopherol markedly diminished the time of maximal activation of extracellular signal-regulated kinase 1/2 (ERK 1/2) and protein kinase B (Akt)-induced in PC12 cells by H(2)O(2). Inhibitors of MEK 1/2, PI 3-kinase and protein kinase C (PKC) diminished the protective effect of α-tocopherol against H(2)O(2)-initiated toxicity if the pre-incubation time was long. The modulation of ERK 1/2, Akt and PKC activities appears to participate in the protection by α-tocopherol against H(2)O(2)-induced death of PC12 cells. The data obtained suggest that inhibition by α-tocopherol in late stage ERK 1/2 and Akt activation induced by H(2)O(2) in PC12 cells makes contribution to its protective effect, while total inhibition of these enzymes is not protective.

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The figure shows the effect of pre-incubation for 30 min with protein kinase inhibitors before cell exposure to 0.3 mM H2O2 for 20 min on ERK 1/2, Akt, pERK 1/2 and pAkt level in PC12 cells. In this figure, HP is hydrogen peroxide. (A) Results of immunoblotting studies; (B) Effect of protein kinase inhibitors on pERK 1/2 level in PC12 cells; (C) Effect of protein kinase inhibitors on pAkt level in PC12 cells. In (B,C): x,xx the difference with the values obtained after exposure to H2O2 alone is significant; xp < 0.01; xxp < 0.05. In the figure, LY is 50 μM LY294002, GF is 1 μM GF109203X, genist is 100 μM genistein, K252 is 1 μM K252a, 10 μM SL327 and 10 μM H89 were used.
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f8-ijms-13-11543: The figure shows the effect of pre-incubation for 30 min with protein kinase inhibitors before cell exposure to 0.3 mM H2O2 for 20 min on ERK 1/2, Akt, pERK 1/2 and pAkt level in PC12 cells. In this figure, HP is hydrogen peroxide. (A) Results of immunoblotting studies; (B) Effect of protein kinase inhibitors on pERK 1/2 level in PC12 cells; (C) Effect of protein kinase inhibitors on pAkt level in PC12 cells. In (B,C): x,xx the difference with the values obtained after exposure to H2O2 alone is significant; xp < 0.01; xxp < 0.05. In the figure, LY is 50 μM LY294002, GF is 1 μM GF109203X, genist is 100 μM genistein, K252 is 1 μM K252a, 10 μM SL327 and 10 μM H89 were used.

Mentions: As Figure 8 shows, in the presence of 10 μM SL327, pERK 1/2 is not revealed in PC12 cells, while in the presence of 50 μM LY294002, pAkt is absent in these cells. The effect of other inhibitors used will be described later (after Figures 9 and 10).


α-Tocopherol at nanomolar concentration protects PC12 cells from hydrogen peroxide-induced death and modulates protein kinase activities.

Zakharova IO, Sokolova TV, Bayunova LV, Vlasova YA, Rychkova MP, Avrova NF - Int J Mol Sci (2012)

The figure shows the effect of pre-incubation for 30 min with protein kinase inhibitors before cell exposure to 0.3 mM H2O2 for 20 min on ERK 1/2, Akt, pERK 1/2 and pAkt level in PC12 cells. In this figure, HP is hydrogen peroxide. (A) Results of immunoblotting studies; (B) Effect of protein kinase inhibitors on pERK 1/2 level in PC12 cells; (C) Effect of protein kinase inhibitors on pAkt level in PC12 cells. In (B,C): x,xx the difference with the values obtained after exposure to H2O2 alone is significant; xp < 0.01; xxp < 0.05. In the figure, LY is 50 μM LY294002, GF is 1 μM GF109203X, genist is 100 μM genistein, K252 is 1 μM K252a, 10 μM SL327 and 10 μM H89 were used.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3472762&req=5

f8-ijms-13-11543: The figure shows the effect of pre-incubation for 30 min with protein kinase inhibitors before cell exposure to 0.3 mM H2O2 for 20 min on ERK 1/2, Akt, pERK 1/2 and pAkt level in PC12 cells. In this figure, HP is hydrogen peroxide. (A) Results of immunoblotting studies; (B) Effect of protein kinase inhibitors on pERK 1/2 level in PC12 cells; (C) Effect of protein kinase inhibitors on pAkt level in PC12 cells. In (B,C): x,xx the difference with the values obtained after exposure to H2O2 alone is significant; xp < 0.01; xxp < 0.05. In the figure, LY is 50 μM LY294002, GF is 1 μM GF109203X, genist is 100 μM genistein, K252 is 1 μM K252a, 10 μM SL327 and 10 μM H89 were used.
Mentions: As Figure 8 shows, in the presence of 10 μM SL327, pERK 1/2 is not revealed in PC12 cells, while in the presence of 50 μM LY294002, pAkt is absent in these cells. The effect of other inhibitors used will be described later (after Figures 9 and 10).

Bottom Line: For the first time, the protective effect of α-tocopherol was shown to depend on its concentration in the nanomolar range (1 nM < 10 nM < 100 nM), if the pre-incubation time was 18 h.Nanomolar and micromolar α-tocopherol decreased the number of PC12 cells in late apoptosis induced by H(2)O(2) to the same extent if pre-incubation time was 18 h.The data obtained suggest that inhibition by α-tocopherol in late stage ERK 1/2 and Akt activation induced by H(2)O(2) in PC12 cells makes contribution to its protective effect, while total inhibition of these enzymes is not protective.

View Article: PubMed Central - PubMed

Affiliation: Department of Comparative Neurochemistry, Institute of Evolutionary Physiology and Biochemistry of Russian Academy of Sciences, Thorez avenue, 44, Saint-Petersburg 194223, Russia; E-Mails: zakhar@iephb.ru (I.O.Z.); sokolt1956@mail.ru (T.V.S.); bayunoval@mail.ru (L.V.B.); yousia@mail.ru (Y.A.V.); involved@mail.ru (M.P.R.).

ABSTRACT
The aim of this work was to compare protective and anti-apoptotic effects of α-tocopherol at nanomolar and micromolar concentrations against 0.2 mM H(2)O(2)-induced toxicity in the PC12 neuronal cell line and to reveal protein kinases that contribute to α-tocopherol protective action. The protection by 100 nM α-tocopherol against H(2)O(2)-induced PC12 cell death was pronounced if the time of pre-incubation with α-tocopherol was 3-18 h. For the first time, the protective effect of α-tocopherol was shown to depend on its concentration in the nanomolar range (1 nM < 10 nM < 100 nM), if the pre-incubation time was 18 h. Nanomolar and micromolar α-tocopherol decreased the number of PC12 cells in late apoptosis induced by H(2)O(2) to the same extent if pre-incubation time was 18 h. Immunoblotting data showed that α-tocopherol markedly diminished the time of maximal activation of extracellular signal-regulated kinase 1/2 (ERK 1/2) and protein kinase B (Akt)-induced in PC12 cells by H(2)O(2). Inhibitors of MEK 1/2, PI 3-kinase and protein kinase C (PKC) diminished the protective effect of α-tocopherol against H(2)O(2)-initiated toxicity if the pre-incubation time was long. The modulation of ERK 1/2, Akt and PKC activities appears to participate in the protection by α-tocopherol against H(2)O(2)-induced death of PC12 cells. The data obtained suggest that inhibition by α-tocopherol in late stage ERK 1/2 and Akt activation induced by H(2)O(2) in PC12 cells makes contribution to its protective effect, while total inhibition of these enzymes is not protective.

Show MeSH
Related in: MedlinePlus