Pigment-Epithelium-Derived Factor Is Upregulated in Photocoagulated Human Retinal Pigment Epithelial Cells

Abstract

There is much evidence that pigment-epithelium-derived factor (PEDF) is a potent antiangiogenic cytokine which inhibits retinal and choroidal neovascularization by inducing apoptosis in activated vascular endothelial cells. Furthermore, the regulation of PEDF appears to be linked to the regulation of vascular endothelial growth factor (VEGF), one of the most potent inducers of intraocular neovascularization. Previous studies have established that thermal photocoagulation, the mainstay in the therapy of various neovascular diseases of the posterior segment, results in a decrease in intraocular concentrations of VEGF and other angiogenic growth factors, thereby inhibiting active retinal neovascularization. In the current study, we sought to determine whether thermal photocoagulation has the potential to regulate the expression of PEDF in human retinal pigment epithelial (RPE) cells. Cultures of RPE cells were photocoagulated with a 532-nm diode laser. Subsequently, RNA was isolated for RT-PCR, and whole-cell extracts and precipitated cell culture supernatant were subjected to Western blot analysis. According to our results, PEDF mRNA and protein are significantly upregulated after photocoagulation. Moreover, PEDF protein was found to be secreted in the cell culture medium.

Expression of Ubiquitin Carboxy-Terminal Hydrolase-L1 in Photocoagulated Human Retinal Pigment Epithelial Cells

“…To date, there is increasing evidence that thermal photocoagulation of RPE cells stimulates the biosynthesis of various mediators such as transforming growth factor-β 2 (TGF-β 2 ) or pigment epithelium derived growth factor (PEDF), a cytokine that has been reported to counteract the effects of proangiogenic growth factors. 2,6,7 In the current study, we observed a time-dependent increase in ubiquitin carboxy-terminal hydrolase-L1 expression in cultures of retinal pigment epithelial cells after thermal photocoagulation. This enzyme is part of the proteasomal degradation machinery and highly expressed in various layers of the retina including the retinal pigment epithelium.…”

Laser Resensitization of Medically Unresponsive Neovascular Age-Related Macular Degeneration

“…In dysfunctional RPE cells, HSP stimulation by SDM results in normalized cytokine expression and consequently improved retinal structure and function. 8,9,20,21,[23][24][25][26][27][28][29][30][31][32][33] As noted above, the therapeutic effects of this "lowintensity" laser-tissue interaction are amplified in SDM by "high-density" laser application, recruiting all the dysfunctional RPE in the targeted area, thereby maximizing the treatment effect. 6 These are the defining principles of SDM.…”

Pigment epithelium-derived factor and vascular endothelial growth factor in branch retinal vein occlusion with macular edema

“…Furthermore, changes of retinal VEGF mRNA expression after laser photocoagulation were confined to RPE cells in miniature pigs, with reduced mRNA expression immediately after photocoagulation and a return to normal by 42 days [30]. Moreover, it was reported that PEDF is produced at high levels by cultured RPE cells after photocoagulation, suggesting that PEDF plays a role in inhibiting neovascularization [31,32]. In the adult rat retina, a high PEDF level was maintained from 6 hours to 24 hours after photocoagulation, and then it gradually decreased [31].…”