Abstract
Purpose: :
RPE cells and microvascular EC play a major role in the development of choroidal neovascularization (CNV). Our aim was to investigate the interaction between RPE cells and EC in coculture, and to explore the influence of RPE on the EC angiogenic activity
Methods: :
RPE and EC were grown alone or in coculture for 3-14 days, under normoxia or hypoxic conditions. Separation of EC and RPE from coculture was achieved by using antibodies specific to each cell type. EC pro- and antiangiogenic gene expression was analyzed using a Real- time PCR array containing 88 genes associated with either positive or negative regulation of angiogenesis. Tube formation assay on ECM was used to study the functional effect of EC coculture with RPE.
Results: :
Coculture of EC with RPE under normoxic conditions induced markedly upregulated EC mRNA expression of 10 genes involved in positive regulation of angiogenesis, among them VEGF, HIF -1 alpha, as well as collagen IV, The expression of EC VEGF was further enhanced by coculture with RPE under hypoxic conditions. Exposure of EC to hypoxia alone induced significant upregulation in the expression of the 10 genes upregulated by coculture with RPE (see Table below). Following coculture with RPE, EC demonstrated enhanced tube formation on ECM.
Conclusions: :
Coculture with RPE enhances the proangiogenic potential of EC under normoxia, which is further enhanced by hypoxia. These data suggest that EC residing in close proximity to RPE cells might be more prone to hypoxia- induce angiogenesis involved in CNV.
Keywords: choroid: neovascularization • gene microarray • retinal degenerations: cell biology