Pigment Epithelium–Derived Factor Is a Substrate for Matrix Metalloproteinase Type 2 and Type 9: Implications for Downregulation in Hypoxia

摘要: PURPOSE. Pigment epithelium– derived factor (PEDF), a protein secreted by the retinal pigment epithelium (RPE), acts on survival and angiogenesis. Because hypoxia VEGF regulate matrix metalloproteinases (MMPs), their effects PEDF proteolysis were explored. METHODS. Mouse models for retinopathy of prematurity (ROP) used. Cultured monkey RPE cells exposed to low oxygen chemical mimetics. mRNA levels in determined RT-PCR. MMPs assessed zymography, DQ-gelatin degradation solution assays, MMP immunostaining. was assayed followed SDS-PAGE induction performed baby hamster kidney (BHK) cells. Retinal R28 cell survival, ex vivo chick embryonic aortic vessel sprouting, directed angiogenesis assays performed. RESULTS. Levels RPE/choroid significantly decreased ROP model. Hypoxia media conditioned cells, with no significant change mRNA. Conversely, proteolysis, gelatinolytic activities 57-kDa 86-kDa zymogens, MMP-2 immunoreactivities increased hypoxia. Addition BHK caused time dose-related upregulation zymogens DQ-gelatinolytic PEDF-degrading activity. The activity shared protease inhibition patterns those vitreous. Limited -9 degraded Ca 2 -dependent fashion. MMP-mediated abolished antiangiogenic protein. CONCLUSIONS. can downregulate through proteolytic degradation. is novel substrate -9. These results reveal posttranslational mechanism downregulating PEDF, provide an explanation hypoxia-provoked increases VEGF/PEDF ratios, and/or neuronal death. (Invest Ophthalmol Vis Sci. 2005;46:2736 –2747) DOI:10.1167/iovs.04-1489