Abstract
Abstract: :
Purpose: To determine whether replicatively senescent human retinal pigment epithelial (RPE) cells express different levels of cytokines and angiogenic factors, compared with non-senescent RPE cells. Methods: Human fetal RPE cells were isolated from fetal eyes and were cultured in Dulbeccoís modified Eagleís medium supplemented with 10% FBS. Total RNA from RPE cell P5 and P19 cultures was extracted and treated with DNase. The Atlas human cDNA expression arrays containing 588 genes in duplicate (Clontech Catalag #7733) were used. cDNA probes were generated from each RNA sample using [a-33P]dATP as a radiolabel and hybridized to the nylon arrays . Following post hybridization washes the images of hybridized signals were scannedusing phosphorimager and analysed using Imagene 4.0 and GeneSpring software. The data in duplicate were normalized and compared between P5 and P19. Results: The gene expression levels of some growth factors, cytokines, and related proteins were increased in P19 RPE cells, as compared with P5 cells. These genes include vascular endothelial growth factor D (VEGFD) (32.0-fold), transforming growth factor-beta 3 (TGF-beta3) (3.2-fold), interleukin-6 precursor (IL-6) (2.7-fold), tumor necrosis factor receptor 1 (TNFR1) (1.9-fold), glial growth factor 2 precursor (GGFHPP2) (1.2-fold), etc. Conclusion: The findings show that there is altered gene expression of angiogenic and growth factors in replicatively senescent RPE cells compared with non-senescent RPE cells. The changes of angiogenic factors expressed by senescent RPE cells may initiate choroidal neovascularization in age-related macular degeneration.
Keywords: 308 age-related macular degeneration • 423 growth factors/growth factor receptors • 561 retinal degenerations: cell biology