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Published on: February 4, 2015
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Regulation of RPE65 expression in human retinal pigment epithelium cells
Olga A Postnikova1,2, Samuel William1, Sheetal Uppal1
1Laboratory of Retinal Cell & Molecular Biology, National Eye Institute, NIH, Bethesda, MD, 20892, USA.
Scientific Reports
|July 27, 2025
Summary
Investigating RPE65 regulation in retinal pigment epithelium (RPE) cells reveals that metabolic and transcriptional factors, not translation, primarily control RPE65 expression. Feeding with rod outer segments (ROS) decreases RPE65 levels.
Area of Science:
- Ophthalmology
- Cell Biology
- Biochemistry
Background:
- The visual cycle in the retinal pigment epithelium (RPE) is crucial for photoreceptor function, relying on RPE65 (retinol isomerase) for chromophore regeneration.
- RPE65 expression is notably lower in RPE cell culture models compared to native RPE, hindering research into the visual cycle.
- Understanding RPE65 regulation is key to improving RPE cell models for studying retinal diseases.
Purpose of the Study:
- To identify the primary drivers of RPE65 gene and protein expression regulation.
- To compare RPE65 expression in different cell culture conditions and assess transcriptional versus translational control.
- To investigate the impact of RPE functions, like phagocytosis, on RPE65 expression.
Main Methods:
- Comparative transcriptional profiling of native RPE and cell culture models.
- Culturing ARPE-19 cells in media supplemented with pyruvate (PYR) or nicotinamide (NAM).
- Assessing RPE65 regulation through transfection experiments and microRNA analysis.
Main Results:
- RPE65 mRNA and protein levels were significantly higher in NAM-supplemented media compared to PYR-supplemented media.
- Transcriptional regulation, rather than translational effects, was found to be the dominant factor in RPE65 expression.
- Feeding cells with rod outer segments (ROS) led to decreased RPE65 expression in NAM-grown cells, indicating a complex interplay between RPE functions.
Conclusions:
- RPE65 expression in ARPE-19 cells is multifactorial, primarily influenced by metabolic and transcriptional status.
- Translational control plays a minor role in regulating RPE65 levels.
- The downregulation of RPE65 by ROS suggests that RPE functions, including the visual cycle and phagocytosis, are not always positively correlated.
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