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EGCG-mediated autophagy flux has a neuroprotection effect via a class III histone deacetylase in primary neuron cells.

Lee JH, Moon JH, Kim SW, Jeong JK, Nazim UM, Lee YJ, Seol JW, Park SY - Oncotarget (2015)

Bottom Line: The results showed that EGCG protects the neuronal cells against human prion protein-induced damage through inhibiting Bax and cytochrome c translocation and autophagic pathways by increasing LC3-II and reducing and blocking p62 by using ATG5 small interfering (si) RNA and autophagy inhibitors.We further demonstrated that the neuroprotective effects of EGCG were exhibited by a class III histone deacetylase; sirt1 activation and the neuroprotective effects attenuated by sirt1 inactivation using sirt1 siRNA and sirtinol.We demonstrated that EGCG activated the autophagic pathways by inducing sirt1, and had protective effects against human prion protein-induced neuronal cell toxicity.

View Article: PubMed Central - PubMed

Affiliation: Biosafety Research Institute, College of Veterinary Medicine, Chonbuk National University, Jeonju, Jeonbuk, South Korea.

ABSTRACT
Prion diseases caused by aggregated misfolded prion protein (PrP) are transmissible neurodegenerative disorders that occur in both humans and animals. Epigallocatechin-3-gallate (EGCG) has preventive effects on prion disease; however, the mechanisms related to preventing prion diseases are unclear. We investigated whether EGCG, the main polyphenol in green tea, prevents neuron cell damage induced by the human prion protein. We also studied the neuroprotective mechanisms and proper signals mediated by EGCG. The results showed that EGCG protects the neuronal cells against human prion protein-induced damage through inhibiting Bax and cytochrome c translocation and autophagic pathways by increasing LC3-II and reducing and blocking p62 by using ATG5 small interfering (si) RNA and autophagy inhibitors. We further demonstrated that the neuroprotective effects of EGCG were exhibited by a class III histone deacetylase; sirt1 activation and the neuroprotective effects attenuated by sirt1 inactivation using sirt1 siRNA and sirtinol. We demonstrated that EGCG activated the autophagic pathways by inducing sirt1, and had protective effects against human prion protein-induced neuronal cell toxicity. These results suggest that EGCG may be a therapeutic agent for treatment of neurodegenerative disorders including prion diseases.

No MeSH data available.


Related in: MedlinePlus

EGCG protects PrP (106-126)-induced mitochondrial damageSH-SY5Y cells were pretreated with 2.5, 5, or 10 μM of EGCG for 1 hr and then exposed to 50 μM PrP (106-126) for 36 hr. The treated cells were measured for JC-1 mono form (green) by flow cytometry. Percent values in the histogram represent the population of JC-1 monomeric cells. A. The treated cells were measured for JC-1 aggregates form (red) and mono form (green) by confocal microscopy analysis. Scale bar = 50 μm B. Separation of the cytosol and mitochondrial extracts was analyzed by Western blot using antibodies, to cytochrome c and Bax protein D, E. Bars indicate mean ± standard error (n = 4). The data were analyzed using ANOVA and Tukey multiple range tests (P < 0.01). Means sharing a common alphabetical symbol did not significantly differ.
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Figure 2: EGCG protects PrP (106-126)-induced mitochondrial damageSH-SY5Y cells were pretreated with 2.5, 5, or 10 μM of EGCG for 1 hr and then exposed to 50 μM PrP (106-126) for 36 hr. The treated cells were measured for JC-1 mono form (green) by flow cytometry. Percent values in the histogram represent the population of JC-1 monomeric cells. A. The treated cells were measured for JC-1 aggregates form (red) and mono form (green) by confocal microscopy analysis. Scale bar = 50 μm B. Separation of the cytosol and mitochondrial extracts was analyzed by Western blot using antibodies, to cytochrome c and Bax protein D, E. Bars indicate mean ± standard error (n = 4). The data were analyzed using ANOVA and Tukey multiple range tests (P < 0.01). Means sharing a common alphabetical symbol did not significantly differ.

Mentions: Mitochondrial dysfunction is related to neuronal cell death caused by prions [46]. This study also examined whether an increase in Sirt1 activity causes prion-mediated mitochondrial impairment. Treatment of 50 μM PrP (106-126) increased green fluorescence indicating a lower MTP, whereas decreased PrP (106-126)-induced green fluorescence in cells pre-treated with EGCG (10 μM) (Figure 2A). These data were reconfirmed by measuring JC-1 using fluoroscopy (Figure 2B), PrP (106-126) treatment induced green fluorescence indicating a lower MTP, and PrP (106-126) treatment changed red fluorescence indicating a normal MTP following EGCG pretreatment (Figure 2B and 2C). In the same manner, PrP (106-126)-treated cells led to Bax translocation in the mitochondria, which increased cytochrome c release into the cytosol, whereas PrP (106-126)-induced Bax translocation and cytochrome c release decreased following EGCG treatment in SH-SY5Y cells. EGCG prevented PrP (106-126)-induced Bax translocation and cytochrome c release (Figure 2D and 2E). These data suggest that EGCG treatment inhibits the PrP (106-126)-mediated mitochondrial apoptotic pathway.


EGCG-mediated autophagy flux has a neuroprotection effect via a class III histone deacetylase in primary neuron cells.

Lee JH, Moon JH, Kim SW, Jeong JK, Nazim UM, Lee YJ, Seol JW, Park SY - Oncotarget (2015)

EGCG protects PrP (106-126)-induced mitochondrial damageSH-SY5Y cells were pretreated with 2.5, 5, or 10 μM of EGCG for 1 hr and then exposed to 50 μM PrP (106-126) for 36 hr. The treated cells were measured for JC-1 mono form (green) by flow cytometry. Percent values in the histogram represent the population of JC-1 monomeric cells. A. The treated cells were measured for JC-1 aggregates form (red) and mono form (green) by confocal microscopy analysis. Scale bar = 50 μm B. Separation of the cytosol and mitochondrial extracts was analyzed by Western blot using antibodies, to cytochrome c and Bax protein D, E. Bars indicate mean ± standard error (n = 4). The data were analyzed using ANOVA and Tukey multiple range tests (P < 0.01). Means sharing a common alphabetical symbol did not significantly differ.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4496391&req=5

Figure 2: EGCG protects PrP (106-126)-induced mitochondrial damageSH-SY5Y cells were pretreated with 2.5, 5, or 10 μM of EGCG for 1 hr and then exposed to 50 μM PrP (106-126) for 36 hr. The treated cells were measured for JC-1 mono form (green) by flow cytometry. Percent values in the histogram represent the population of JC-1 monomeric cells. A. The treated cells were measured for JC-1 aggregates form (red) and mono form (green) by confocal microscopy analysis. Scale bar = 50 μm B. Separation of the cytosol and mitochondrial extracts was analyzed by Western blot using antibodies, to cytochrome c and Bax protein D, E. Bars indicate mean ± standard error (n = 4). The data were analyzed using ANOVA and Tukey multiple range tests (P < 0.01). Means sharing a common alphabetical symbol did not significantly differ.
Mentions: Mitochondrial dysfunction is related to neuronal cell death caused by prions [46]. This study also examined whether an increase in Sirt1 activity causes prion-mediated mitochondrial impairment. Treatment of 50 μM PrP (106-126) increased green fluorescence indicating a lower MTP, whereas decreased PrP (106-126)-induced green fluorescence in cells pre-treated with EGCG (10 μM) (Figure 2A). These data were reconfirmed by measuring JC-1 using fluoroscopy (Figure 2B), PrP (106-126) treatment induced green fluorescence indicating a lower MTP, and PrP (106-126) treatment changed red fluorescence indicating a normal MTP following EGCG pretreatment (Figure 2B and 2C). In the same manner, PrP (106-126)-treated cells led to Bax translocation in the mitochondria, which increased cytochrome c release into the cytosol, whereas PrP (106-126)-induced Bax translocation and cytochrome c release decreased following EGCG treatment in SH-SY5Y cells. EGCG prevented PrP (106-126)-induced Bax translocation and cytochrome c release (Figure 2D and 2E). These data suggest that EGCG treatment inhibits the PrP (106-126)-mediated mitochondrial apoptotic pathway.

Bottom Line: The results showed that EGCG protects the neuronal cells against human prion protein-induced damage through inhibiting Bax and cytochrome c translocation and autophagic pathways by increasing LC3-II and reducing and blocking p62 by using ATG5 small interfering (si) RNA and autophagy inhibitors.We further demonstrated that the neuroprotective effects of EGCG were exhibited by a class III histone deacetylase; sirt1 activation and the neuroprotective effects attenuated by sirt1 inactivation using sirt1 siRNA and sirtinol.We demonstrated that EGCG activated the autophagic pathways by inducing sirt1, and had protective effects against human prion protein-induced neuronal cell toxicity.

View Article: PubMed Central - PubMed

Affiliation: Biosafety Research Institute, College of Veterinary Medicine, Chonbuk National University, Jeonju, Jeonbuk, South Korea.

ABSTRACT
Prion diseases caused by aggregated misfolded prion protein (PrP) are transmissible neurodegenerative disorders that occur in both humans and animals. Epigallocatechin-3-gallate (EGCG) has preventive effects on prion disease; however, the mechanisms related to preventing prion diseases are unclear. We investigated whether EGCG, the main polyphenol in green tea, prevents neuron cell damage induced by the human prion protein. We also studied the neuroprotective mechanisms and proper signals mediated by EGCG. The results showed that EGCG protects the neuronal cells against human prion protein-induced damage through inhibiting Bax and cytochrome c translocation and autophagic pathways by increasing LC3-II and reducing and blocking p62 by using ATG5 small interfering (si) RNA and autophagy inhibitors. We further demonstrated that the neuroprotective effects of EGCG were exhibited by a class III histone deacetylase; sirt1 activation and the neuroprotective effects attenuated by sirt1 inactivation using sirt1 siRNA and sirtinol. We demonstrated that EGCG activated the autophagic pathways by inducing sirt1, and had protective effects against human prion protein-induced neuronal cell toxicity. These results suggest that EGCG may be a therapeutic agent for treatment of neurodegenerative disorders including prion diseases.

No MeSH data available.


Related in: MedlinePlus