97th DOG Annual Meeting 1999



C. Lehmann1, S. Mirshahi2, J. Soria2, Y. Pouliquen2, M. Mirshahi2, P. Rieck

Purpose: Urokinase (UPA) plays a central role in extracellular proteolysis in a variety of normal and pathological processes involving tissue destruction and cell migration. UPA-binding to its membrane receptor (UPAR) concentrates UPA enzymativ activity on the cell surface. UPA activates growth factors such as HGF, TGFß and UPAR acts as an adhesion molecule for matrix proteins such as vitronectin. In this study we report the presence of UPA and UPAR in cultured human corneal fibroblasts.

Methods: Immunohistochemistry, Western blots and Northern blots were performed on cultured fibroblasts from normal human corneas and corneas with keratokonus. An ELISA was developed for the analysis of UPA-receptor on cultured fibroblasts and in biotinylated membrane protein preparations.

Results: Using specific antibodies, UPA and UPAR immunreactivity was detected on Western Blots of cell extracts and localized on the cell surface. MRNAs for UPA and UPAR were present in the cells. A comparativ study using biotinilated UPAR suggest that the amount of UPA is increased in keratoconus fibroblasts.

Conclusion: UPA and UPAR are present in corneal fibroblasts and may be implicated in the pathogenesis of keratoconus.

1Dept.of Ophthalmology, Virchow-Charité Hospital, Humboldt-University Berlin (FRG),
2University Eye Clinic, Hôtel Dieu Hospital, Paris (France).