Figure 6. Fibroblasts but not myofibroblasts produce angiostatins

Cells from the stromal layer of human corneas were cultured on Type I collagen coated plastic in serum free medium containing either FGF-2 (for fibroblasts, FIB) or TGFβ1 (for myofibroblasts, MYO). After 7 days in the presence of the growth factors, plasminogen (33 nM final) was added to the cultures and samples were taken at 24, 48, and 72 h. The media from three separate cultures at the three time points were separated by SDS-PAGE under nonreducing conditions and transblotted. The blots were probed with a mixture of two antibodies directed to K1-3 of plasminogen. Fibroblasts converted plasminogen (Plgn) to angiostatin-like molecules and by 48 h only a trace of full-length plasminogen was detectable. Myofibroblast cultures generated only a trace amount of the 45 kDa form of angiostatin by 72 h.