MOCHIZUKI Manabu Tokyo Medical and Dental University, Ophthalmology, Professor, 大学院・医歯学総合研究科, 教授 (10010464)
MORITA Ikuo Tokyo Medical and Dental University, Cellular Physiological Chemistry, Professor, 大学院・医歯学総合研究科, 教授 (60100129)
We investigated gene expression profiles of vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) In differentiated and non-differentiated retinal pigment epithelial (RPE) cells during oxidative stress. Human RPE cells were grown in culture on laminin-coated flasks to obtain differentiated features. Cells cultured on 'plastic were used as non-differentiated controls. After confluence, hydrogen peroxide (H202) was added for 48 h, then, total RNA was extracted and used for RT-PCR and Northern blot analysis. Medium conditioned by RPE was used for ELISA, Western blotting, and in vitro angiogenesis assay. As a result, differehtiated RPE cells expressed significantly higher levels of VEGE protein, as compared to their non-differentiated counterpails. The expression pattern remained consistent even after cellular exposure to H_O_2. Conversely, while elevated levels of PEDF transcript and protein were seen in differentiated RPE cells, compared to non-differentiated dells, a marked decrease at both PEDF mRNA and protein levels was seen after treatment with H_2O_2 Moreover, this decrease in PEDF. expression was dosage dependent In in vitro angiogenesis assay, conditioned medium from differentiated human RPE cells after exposure to H_2O_2 showed a dramatic increase 'in tubular formation and migratory activity of microvascular endothelial cell& These data suggest that, in physiological conditions, a critical balance between PEDF and VEGF exists, and PEDF may counteract the angiogenic potential of VEOF. Under oxidative stress, PEOF decreases disrupting this balance. This equilibrium shift may be significant in promoting a pathological condition of RPE cells and contributing to choroidal neovascularization in age-related macular degeneration.