Epitheliomesenchymal transdifferentiation of cultured RPE cells.

Area of Science:

• Ophthalmology
• Cell Biology
• Biochemistry

Background:

• Retinal pigment epithelium (RPE) cells in proliferative vitreoretinopathy (PVR) membranes exhibit fibroblast-like characteristics, deviating from their epithelial nature.
• This cellular transformation, known as metaplasia, is implicated in the fibrotic processes contributing to PVR.

Purpose of the Study:

• To investigate the in vitro transdifferentiation of porcine RPE cells.
• To evaluate the effects of transforming growth factor-beta2 (TGF-β2) on RPE cell proliferation, phenotype, collagen synthesis, and alpha-smooth muscle actin (α-SMA) expression.

Main Methods:

• Primary and 10th-passaged porcine RPE cells were cultured.
• Cell proliferation, phenotype changes, collagen synthesis (including type VIII collagen), and α-SMA expression were analyzed in response to varying doses of TGF-β2.
• Confocal laser microscopy was used for visualization.

Main Results:

• TGF-β2 inhibited primary RPE cell proliferation but not that of 10th-passaged cells.
• Collagen synthesis was stimulated by TGF-β2 in both cell types, with a more pronounced effect in 10th-passaged cells.
• 10th-passaged RPE cells showed significantly higher α-SMA production compared to primary RPE cells, indicating a shift towards a myofibroblast-like phenotype.

Conclusions:

• RPE cell metaplasia, characterized by altered biological behavior, is a critical predisposing factor in the pathogenesis of PVR.
• The study demonstrates that TGF-β2 significantly influences RPE cell phenotype and extracellular matrix production, mimicking changes observed in PVR membranes.