Abstract
PURPOSE. Understanding the role of mitochondria in retinal ganglion cells (RGCs) is relevant to human disease as studies have shown mitochondrial abnormalities in primary open-angle glaucoma patients. This study seeks to determine the effects of the sigma-1 receptor (σ-1r) and its agonists on mitochondrial function in oxygen-and glucose-deprived (OGD) purified neonatal RGCs. METHODS. Retinal ganglion cells were isolated from rat pups and subjected to OGD in varying conditions in the presence or absence of σ-1r agonist and antagonist and following addition of an AAV2-σ-1r vector that was used to increase σ-1r expression. Western blots and immunofluorescence microscopy validated findings. Mitochondrial function was determined by measuring mitochondrial membrane potential (Δψm) using the dye, fluorescence tetraethylbenzimidazolylcarbocyanineiodide (JC-1), and determination of cytochrome c oxidase activity using a cytochrome c oxidase assay kit. Caspase 3 and 7 activities were also measured using a luminescent assay kit. RESULTS. Oxygen and glucose deprivation in RGCs resulted in decreased mitochondrial membrane potential and cytochrome c oxidase activity when compared with normoxic RGCs. σ-1r agonists or overexpression of the σ-1r restored the mitochondrial membrane potential comparable to normoxic conditions, while σ-1r antagonists abolished these effects. Oxygen and glucose depreavtation induced decreases in cytochrome c activity were partially restored by overexpression or activation of σ-1r. Caspase activity was increased in response to OGD and was decreased by the addition of σ-1r agonist, pentazocine, and following σ-1r overexpression. CONCLUSIONS. These data suggest that activation and/or overexpression of σ-1r restores RGCs mitochondrial function following OGD and that mitochondrial function is vital to the function of RGCs.
Original language | English |
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Pages (from-to) | 2755-2764 |
Number of pages | 10 |
Journal | Investigative Ophthalmology and Visual Science |
Volume | 58 |
Issue number | 5 |
DOIs | |
State | Published - May 2017 |
Keywords
- Mitochondria
- Oxygen and glucose deprived
- Retinal ganglion cells
- Sigma-1 receptor