Plasminogen activator inhibitor-1 mRNA expression in cultured pigmented ciliary epithelial cells of the porcine eye.
BACKGROUND
Plasminogen activator inhibitor-1 (PAI-1) is a main regulator of the fibrinolytic system. PAI-1 inhibits tissue plasminogen activator and urokinase-type plasminogen activator, resulting in reduced plasminogen activity and attenuated fibrinolysis and proteolysis. The present study was performed to determine the gene expression encoding for PAI-1 in cultured pigmented ciliary epithelial cells of the porcine eye and to detect PAI-1 activity in cell culture supernatants.


METHODS
Total mRNA of respective confluent primary cultures of porcine ciliary epithelial cells, porcine liver cells and porcine kidney cells was isolated. Reverse transcribed PAI-1 mRNA was measured by real-time polymerase chain reaction (TaqMan PCR) with PAI-1 primers and probes deduced from the human PAI-1 gene. PAI-1 activity in supernatants of the cell cultures was determined by a specific chromogenic test (Coatest PAI).


RESULTS
PAI-1 mRNA was localized in all samples of primary cultures of porcine pigmented ciliary epithelial cells. As a negative control we analyzed total mRNA of porcine kidney cells. PAI-1 mRNA was not detectable in these cells. On the other hand, we established PAI-1 mRNA in porcine liver cells as a positive control. High levels of PAI-1 activity were found in all samples of cell culture supernatants.


CONCLUSIONS
Our results indicate that PAI-1 is produced and secreted by the porcine ciliary epithelium. We suggest that PAI-1 together with components of the fibrin/fibrinolytic system may be involved in aqueous humor outflow. Overproduction of PAI-1 may induce less fibrinolysis and extracellular proteolysis in aqueous humor and trabecular meshwork, which could result in an elevated intraocular pressure by increasing the outflow obstruction. Therefore stimulation of PAI-1 production may perhaps contribute to the pathogenesis of primary open-angle glaucoma.
Meyer
Michael W
MW
Department of Ophthalmology, Medical School Hanover, Carl-Neuberg-Strasse 1, 30625 Hanover, Germany. drmichaelmeyer@web.de
von Depka
Mario
M
Wilhelm
Christian
C
Schröder
Anke
A
Erb
Carl
C
D000818:Animals; D002478:Cells, Cultured; D002924:Ciliary Body / Q000166:cytology*; D015870:Gene Expression; D010857:Pigment Epithelium of Eye / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015842:Serine Proteinase Inhibitors / Q000096:biosynthesis / Q000235:genetics*; D013552:Swine
D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D015842:Serine Proteinase Inhibitors