Vasohibin-1 and retinal pigment epithelium

Abstract

Vascular endothelial growth factor (VEGF) is one of the main factors for inducing choroidal neovascularization in patients with age-related macular degeneration (AMD). Retinal pigment epithelium (RPE) is one of the main sources for expressing VEGF. Vasohibin-1 is a VEGF-inducible gene in human cultured endothelial cells with antiangiogenic properties. We examined the effects of vasohibin-1 against RPE. We used rat RPE cell line, RPE-J. Cobalt chloride and low glucose and oxygen supply were used for hypoxic stress. Western blot analysis and real-time PCR were performed to detect the expression of vasohibin-1 and VEGF in the RPE-J. Cobalt chloride or low oxygen and low glucose enhanced VEGF expression, whereas statistically significant less vasohibin-1 expression was observed. RPE cell dynamics was monitored using xCELLigence System for real-time cell analysis during culture. External VEGF (0.2-2 nM) enhanced Cell Index (CI), such as cell viability, number, and adhesion to the plates significantly at 2% oxygen and no glucose when compared to those of vehicle or other concentration of VEGF. Conversely, external vasohibin-1 (2 nM) showed lower CI at the indicated condition. Vasohibin-1 also reduced VEGF-induced CI index. These results were not observed under standard culture condition. When we performed MTS assay or cell count, external vasohibin-1 also showed comparable results. When we transduced full-length vasohibin-1 cDNA in RPE-J, the internal vasohibin-1 showed less VEGF expression than that of control vector-transduced RPE-J. In summary, vasohibin-1 showed opposite results as that of VEGF on the RPE-J, especially under hypoxic condition. © 2012 Springer Science+Business Media, LLC.