Purpose: Matrix metalloproteinases (MMP)-2 and -9 play an important role in the pathogenesis of choroidal neovascularization (CNV). Retinal pigment epithelial cells (RPE) are an important source of MMPs in the outer retinal environment, however little is known about the local factors that modulate MMP secretion in these cells. The purpose of this study was to determine the effects of CNV involved growth factors and the extracellular matrix molecule fibronectin on MMP-2 and -9 secretion by cultured human RPE.
Methods: MMP-2 and -9 secretion was studied using gelatin zymography, Western blot, and ELISA assay of RPE culture supernatants. The effects of stimulating the cells for 36 hours with vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bGFG), tumor necrosis factor-alpha (TNF-alpha), or fibronectin (FN), all angiogenic factors found in CNV membranes, was determined.
Results: Resting RPE cells secreted MMP-2 but not MMP-9. Stimulation with TNF-alpha induced secretion of MMP-9 and increased the secretion of MMP-2. MMP-2 secretion was also increased by stimulation with FN and VEGF, but not bFGF.
Conclusion: The results indicated that the angiogenic molecules VEGF, FN, and TNF-alpha stimulate MMP-2 and -9 secretion from RPE and thus further promote CNV.