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Inhibition of oxidative stress by coenzyme Q10 increases mitochondrial mass and improves bioenergetic function in optic nerve head astrocytes.

Noh YH, Kim KY, Shim MS, Choi SH, Choi S, Ellisman MH, Weinreb RN, Perkins GA, Ju WK - Cell Death Dis (2013)

Bottom Line: In contrast, CoQ10 not only prevented activation of ONH astrocytes but also significantly decreased SOD2 and HO-1 protein expression in the ONH astrocytes against oxidative stress.Finally, oxidative stress triggered the upregulation of OXPHOS Cx protein expression, as well as reduction of cellular adeonsine triphosphate (ATP) production and increase of ROS generation in the ONH astocytes.However, CoQ10 preserved OXPHOS protein expression and cellular ATP production, as well as decreased ROS generation in the ONH astrocytes.

View Article: PubMed Central - PubMed

Affiliation: Laboratory for Optic Nerve Biology, Hamilton Glaucoma Center and Department of Ophthalmology, University of California, San Diego, La Jolla, CA, USA.

ABSTRACT
Oxidative stress contributes to dysfunction of glial cells in the optic nerve head (ONH). However, the biological basis of the precise functional role of mitochondria in this dysfunction is not fully understood. Coenzyme Q10 (CoQ10), an essential cofactor of the electron transport chain and a potent antioxidant, acts by scavenging reactive oxygen species (ROS) for protecting neuronal cells against oxidative stress in many neurodegenerative diseases. Here, we tested whether hydrogen peroxide (100 μM H2O2)-induced oxidative stress alters the mitochondrial network, oxidative phosphorylation (OXPHOS) complex (Cx) expression and bioenergetics, as well as whether CoQ10 can ameliorate oxidative stress-mediated alterations in mitochondria of the ONH astrocytes in vitro. Oxidative stress triggered the activation of ONH astrocytes and the upregulation of superoxide dismutase 2 (SOD2) and heme oxygenase-1 (HO-1) protein expression in the ONH astrocytes. In contrast, CoQ10 not only prevented activation of ONH astrocytes but also significantly decreased SOD2 and HO-1 protein expression in the ONH astrocytes against oxidative stress. Further, CoQ10 prevented a significant loss of mitochondrial mass by increasing mitochondrial number and volume density and by preserving mitochondrial cristae structure, as well as promoted mitofilin and peroxisome-proliferator-activated receptor-γ coactivator-1 protein expression in the ONH astrocyte, suggesting an induction of mitochondrial biogenesis. Finally, oxidative stress triggered the upregulation of OXPHOS Cx protein expression, as well as reduction of cellular adeonsine triphosphate (ATP) production and increase of ROS generation in the ONH astocytes. However, CoQ10 preserved OXPHOS protein expression and cellular ATP production, as well as decreased ROS generation in the ONH astrocytes. On the basis of these observations, we suggest that oxidative stress-mediated mitochondrial dysfunction or alteration may be an important pathophysiological mechanism in the dysfunction of ONH astrocytes. CoQ10 may provide new therapeutic potentials and strategies for protecting ONH astrocytes against oxidative stress-mediated mitochondrial dysfunction or alteration in glaucoma and other optic neuropathies.

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Characterization of cultured rat optic nerve head (ONH) astrocytes. (a) The diagram represents purification of ONH astrocytes from rats. (b) The protein extracts from ONH astrocytes were positive for GFAP, a marker for astrocytes but were negative for Iba1, a marker for microglial cells, and MBP, a maker for oligodendrocytes. The protein extract from rat optic nerve tissue was used for positive control. A representative image shows that GFAP immunoreactivity is present in the ONH astrocytes. GFAP, glial fibrillary acidic protein; MBP, myelin basic protein. Scale bar, 20 μm
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fig1: Characterization of cultured rat optic nerve head (ONH) astrocytes. (a) The diagram represents purification of ONH astrocytes from rats. (b) The protein extracts from ONH astrocytes were positive for GFAP, a marker for astrocytes but were negative for Iba1, a marker for microglial cells, and MBP, a maker for oligodendrocytes. The protein extract from rat optic nerve tissue was used for positive control. A representative image shows that GFAP immunoreactivity is present in the ONH astrocytes. GFAP, glial fibrillary acidic protein; MBP, myelin basic protein. Scale bar, 20 μm

Mentions: Pure ONH astrocytes were generated from postnatal day 5 Sprague–Dawley rats using a modification of a previous protocol by Hernandez et al.23 As shown in Figure 1, the cells migrated from cultured ONH tissues were purified by vigorous shaking and serum deprivation (Figure 1a). To confirm whether purified cells were astrocytes, we performed Western blot and immunocytochemical analyses using markers for astrocytes, microglial cells and oligodendrocytes. We found that the purified cells were positive for glial fibrillary acidic protein (GFAP), a marker for astrocytes, but were negative for Iba1, a marker for microglial cells, and myelin basic protein (MBP), a marker for oligodendrocytes (Figure 1b). In contrast, the protein extract from rat ON tissues contained all four of markers. Immunocytochemistry showed a strong immunoreacitivity for GFAP in cultured ONH astrocytes (Figure 1b), suggesting that the purified cells from ONH tissues were astrocytes.


Inhibition of oxidative stress by coenzyme Q10 increases mitochondrial mass and improves bioenergetic function in optic nerve head astrocytes.

Noh YH, Kim KY, Shim MS, Choi SH, Choi S, Ellisman MH, Weinreb RN, Perkins GA, Ju WK - Cell Death Dis (2013)

Characterization of cultured rat optic nerve head (ONH) astrocytes. (a) The diagram represents purification of ONH astrocytes from rats. (b) The protein extracts from ONH astrocytes were positive for GFAP, a marker for astrocytes but were negative for Iba1, a marker for microglial cells, and MBP, a maker for oligodendrocytes. The protein extract from rat optic nerve tissue was used for positive control. A representative image shows that GFAP immunoreactivity is present in the ONH astrocytes. GFAP, glial fibrillary acidic protein; MBP, myelin basic protein. Scale bar, 20 μm
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3824651&req=5

fig1: Characterization of cultured rat optic nerve head (ONH) astrocytes. (a) The diagram represents purification of ONH astrocytes from rats. (b) The protein extracts from ONH astrocytes were positive for GFAP, a marker for astrocytes but were negative for Iba1, a marker for microglial cells, and MBP, a maker for oligodendrocytes. The protein extract from rat optic nerve tissue was used for positive control. A representative image shows that GFAP immunoreactivity is present in the ONH astrocytes. GFAP, glial fibrillary acidic protein; MBP, myelin basic protein. Scale bar, 20 μm
Mentions: Pure ONH astrocytes were generated from postnatal day 5 Sprague–Dawley rats using a modification of a previous protocol by Hernandez et al.23 As shown in Figure 1, the cells migrated from cultured ONH tissues were purified by vigorous shaking and serum deprivation (Figure 1a). To confirm whether purified cells were astrocytes, we performed Western blot and immunocytochemical analyses using markers for astrocytes, microglial cells and oligodendrocytes. We found that the purified cells were positive for glial fibrillary acidic protein (GFAP), a marker for astrocytes, but were negative for Iba1, a marker for microglial cells, and myelin basic protein (MBP), a marker for oligodendrocytes (Figure 1b). In contrast, the protein extract from rat ON tissues contained all four of markers. Immunocytochemistry showed a strong immunoreacitivity for GFAP in cultured ONH astrocytes (Figure 1b), suggesting that the purified cells from ONH tissues were astrocytes.

Bottom Line: In contrast, CoQ10 not only prevented activation of ONH astrocytes but also significantly decreased SOD2 and HO-1 protein expression in the ONH astrocytes against oxidative stress.Finally, oxidative stress triggered the upregulation of OXPHOS Cx protein expression, as well as reduction of cellular adeonsine triphosphate (ATP) production and increase of ROS generation in the ONH astocytes.However, CoQ10 preserved OXPHOS protein expression and cellular ATP production, as well as decreased ROS generation in the ONH astrocytes.

View Article: PubMed Central - PubMed

Affiliation: Laboratory for Optic Nerve Biology, Hamilton Glaucoma Center and Department of Ophthalmology, University of California, San Diego, La Jolla, CA, USA.

ABSTRACT
Oxidative stress contributes to dysfunction of glial cells in the optic nerve head (ONH). However, the biological basis of the precise functional role of mitochondria in this dysfunction is not fully understood. Coenzyme Q10 (CoQ10), an essential cofactor of the electron transport chain and a potent antioxidant, acts by scavenging reactive oxygen species (ROS) for protecting neuronal cells against oxidative stress in many neurodegenerative diseases. Here, we tested whether hydrogen peroxide (100 μM H2O2)-induced oxidative stress alters the mitochondrial network, oxidative phosphorylation (OXPHOS) complex (Cx) expression and bioenergetics, as well as whether CoQ10 can ameliorate oxidative stress-mediated alterations in mitochondria of the ONH astrocytes in vitro. Oxidative stress triggered the activation of ONH astrocytes and the upregulation of superoxide dismutase 2 (SOD2) and heme oxygenase-1 (HO-1) protein expression in the ONH astrocytes. In contrast, CoQ10 not only prevented activation of ONH astrocytes but also significantly decreased SOD2 and HO-1 protein expression in the ONH astrocytes against oxidative stress. Further, CoQ10 prevented a significant loss of mitochondrial mass by increasing mitochondrial number and volume density and by preserving mitochondrial cristae structure, as well as promoted mitofilin and peroxisome-proliferator-activated receptor-γ coactivator-1 protein expression in the ONH astrocyte, suggesting an induction of mitochondrial biogenesis. Finally, oxidative stress triggered the upregulation of OXPHOS Cx protein expression, as well as reduction of cellular adeonsine triphosphate (ATP) production and increase of ROS generation in the ONH astocytes. However, CoQ10 preserved OXPHOS protein expression and cellular ATP production, as well as decreased ROS generation in the ONH astrocytes. On the basis of these observations, we suggest that oxidative stress-mediated mitochondrial dysfunction or alteration may be an important pathophysiological mechanism in the dysfunction of ONH astrocytes. CoQ10 may provide new therapeutic potentials and strategies for protecting ONH astrocytes against oxidative stress-mediated mitochondrial dysfunction or alteration in glaucoma and other optic neuropathies.

Show MeSH
Related in: MedlinePlus