97th DOG Annual Meeting 1999
TGF-(beta): A GROWTH FACTOR INDUCING (alpha)B-CRYSTALLIN EXPRESSION IN CILIARY MUSCLE CELLS
1U. Welge-Lüßen, 2H. Bloemendal, 1E. Lütjen-Drecoll
Purpose: In many glaucomatous eyes, (alpha)B-crystallin is increased in the trabecular meshwork (TM). In a recent study, we have shown that transforming growth factor-(beta) (TGF-(beta)) which is increased in the aqueous humor of patients with primary open angle glaucoma (POAG) induces (alpha)B-crystallin expression in cultured trabecular meshwork cells, but not in fibroblasts. Alternatively to the TM, aqueous humor leaves the eye via the uveoscleral outflow pathways that are lined by ciliary muscle cells (CMC). In the present study we investigated the effect of TGF-(beta) on the expression of (alpha)B-crystallin and the corresponding mRNA in cultured human CMC.
Material and methods: Monolayer cultures of CMC from eyes of 5 human donors (12-73 years) of the third passage being confluent for 7 days were treated with 1.0 ng/ml TGF-(beta)1 or TGF-(beta)2 for 12-96 h. Induction of (alpha)B-Crystallin and the related mRNA was investigated by Western- and Northern-blot analysis.
Results: An increase in (alpha)B-crystallin mRNA was observed following treatment with TGF-(beta)1 and TGF-(beta)2. Different time periods of treatment showed no differences in this effect. Actinomycin did block the induction of (alpha)B-crystallin by the cytokine TGF-(beta). Using Western blotting the increase of aB-crystallin expression in CMC was only small.
Conclusion: TGF-(beta) is a factor presumably inducing the stress protein (alpha)B-crystallin expression in cells lining the aqueous humor outflow pathway.
1Department of Anatomy II, University of Erlangen-Nürnberg,
2Department of Biochemistry, University of Nijmegen, NL-6525 EK Nijmegen