| Which differentiated cell type is used |
| Label |
retinal pigment epithelial cell |
| Link |
http://purl.obolibrary.org/obo/CL_0002586 |
| Description |
An epithelial cell of the retinal pigmented epithelium.; This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies to only to some subtypes and species, and so should not be considered definitional.
Retinal pigment epithelial (RPE) cells form a single layer of cells at the back of the eye sandwiched between the neurosensory retina and the choroid, playing a significant role in maintaining vision health. These pigment-laden cells are highly specialized and perform an array of metabolic and transport functions essential for the maintenance of the photoreceptor cells (rods and cones) in the retina. The pigmentation of RPE cells actively aids in the absorption of excess light and the prevention of light scattering, thus enhancing the eye's optical properties.
The retinal pigment epithelium forms a key part of the blood/retina barrier. The cells have long sheet-like microvilli on their apical membrane that project into the light-sensitive outer segments of the photoreceptors, forming a close structural interaction. The basolateral membrane of the RPE interacts with the underlying Bruch’s membrane, which separates the RPE cells from fenestrated endothelium of the choriocapillaris.
RPE cells support the photoreceptor by providing them with oxygen and nutrients (such as glucose, retinol and fatty acids) and removing waste products. They also recycle the visual pigment, in a process called the "visual cycle", where the RPE cells play a vital role in the regeneration of visual pigment (11-cis retinol) following the absorption of light. This is essential for the maintenance of photoreceptor excitability.
Beyond this, RPE cells take part in the phagocytosis process, where they digest the shed ends of photoreceptor outer segments, thus, preventing the build-up of waste residue that could otherwise harm retinal health. They also secrete various factors, including growth factors required to maintain the structural integrity of choriocapillaris endothelium and photoreceptors, as well as immunosuppressive factors that play an important role in establishing the immune privilege of the eye. |
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