Expression of the metalloproteinase stromelysin in human retinal pigment epithelium (RPE)

Background: Under normal circumstances the retinal pigment epithelium (RPE) does not undergo cell division. After retina I detachment or the development of choroidal neovascularization (CNV) it can be induced to reenter the cell cycle. The RPE cells proliferate and dedifferentiate. A prerequisite for proliferation of RPE cells is degradation of the extracellular matrix (ECM), which may be induced by metalloproteinases. We investigated the potential role of human RPE cells in the expression of the metalloproteinase stromelysin. Materials and methods: Human RPE cells were cultured from donor eyes. Stromelysin was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) from mRNA. Results: Human RPE cells in culture express stromelysin. Its expression is enhanced by tetraphorbolacetate (TPA). Conclusions: Stromelysin generally degrades important constituents of the ECM. This may induce the detachment of RPE cells from the basement membrane and initiate RPE proliferation and dedifferentiation.