Effects of exosomes derived from activated corneal stromal keratocytes on the inflammation, proliferation, neuroprotection and epithelial-mesenchymal transition in retinal pigment epithelium cells.

AIMS: This study investigated the effects of activated keratocyte-derived exosomes (aKExo) on retinal pigment epithelial (RPE) cells in-vitro, focusing on cell viability, inflammatory cytokine expression, and neuroprotective properties.

MATERIALS AND

METHODS

Keratocytes were cultured, and exosomes were extracted and characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), flow cytometry, and dynamic light scattering (DLS). RPE cells, isolated from a human donor, were confirmed via RPE65 expression. aKExo effects on RPE cells were assessed using MTT assay at concentrations from 10-1 (35 μg/mL) to 10-5 (3.5 × 10-3 μg/mL). The optimal aKExo concentration (10-5) enhanced cell viability and exhibited the highest proliferative potential compared to the control group, making it the optimal dose for subsequent experiments including gene expression analysis, and ELISA.

KEY FINDINGS: aKExo downregulated IL-6 mRNA (0.70 ± 0.06, p = 0.0009) and marginally reduced TGF-β mRNA (0.75 ± 0.16, p = 0.0575). ELISA confirmed a reduction in IL-6 (31.33 ± 5.77 pg/mL vs. 50.22 ± 13.47 pg/mL, p = 0.0894) and TGF-β (8.91 ± 0.16 pg/mL vs. 11.39 ± 1.49 pg/mL, p = 0.0460). No significant changes were observed for IL-1β expression or other epithelial-mesenchymal transition (EMT)-related genes (α-SMA, ZEB-1, β-catenin). Neuroprotective genes NGF (4.34 ± 1.05, p = 0.0053) and CD90 (1.55 ± 0.25, p = 0.0184) were significantly upregulated, while VEGF-A was elevated (1.65 ± 0.15, p = 0.0018).

SIGNIFICANCE: These findings highlight aKExo's immunomodulatory, neuroprotective, and anti-EMT effects, suggesting potential therapeutic applications for retinal disorders, while noting that VEGF-A upregulation requires further investigation.