Abstract
Purpose: :
Serpins play and important role in biological processes including those associated with neuronal cell survival and normal vascular functions. The purpose of this study was to examine the expression of Serpins in the retina and RPE cells and their developmental regulation in the eye.
Methods: :
Gene array analysis was performed using RNA extracted from ARPE19 grown in RPMI containing 2% FBS. RNA was isolated with TRIzol, purified with Rneasy, and labeled using the 3DNA Array 900 Kit (Genisphere). Cy3 and Cy9 RNA probes were hybridized to QuantArray–Human OHU28K oligo arrays and data analyzed using GenePix 4000A scanner and software Version 4.0, gene clustering performed with Cluster v2.20, TreeView v1.60 software (EisenLab at UC Berkley) and GO classifications done using the LocuLink database (NCBI). Thresholds were >2–fold expression changes in at least three arrays. Retinas were collected from C57 B/L6 mice at several stages of development and RNA isolated for RT–PCR. RNA isolated from the RPE cells were used to analyze the expression of the Serpins by PCR. Some cultures were treated with 100ng/ml PEDF for 24 and 48hrs to be processed for PCR.
Results: :
Eleven Serpins, including PEDF, were identified in the RPE cells by gene array analysis. RT–PCR analysis confirmed that all 11 Serpins were expressed in the RPE cells and that 9 of the 11 genes were expressed in the retina. The expressions of Serpins B1 and H1 peaked at E17, while the expressions of Serpins A3, B6 and PEDF peaked at PN3. SerpinH1 is expressed at developmental stages only, while SerpinA8 is expressed at postnatal stages only. PEDF downregulated alpha2 Antiplasmin by 11.9% (n=3, p< 0.4) in confluent cells after 48hr. This is one of the two Serpins detected in the RPE but not in the retina.
Conclusions: :
Serpins regulate processes involved with coagulation, complement activation, vascular function, and neuronal cell death. Dysfunction of these proteins is associated with numerous pathologies including degeneration in the brain. The relationship of these proteins to RPE function, retinal development and retinal pathology warrants more attention.
Keywords: retinal pigment epithelium • gene/expression • development