Figure 2 of Lin, Mol Vis 2009; 15:26-37.


Figure 2. Time course effect of norrin on tPA and uPA expression, and on cell survival. RGC-5 cells were left untreated or treated for 24 h and 48 h with staurosporine (SS) only (2.0 μM), norrin only (25 ng/ml), or SS and norrin (n=3 experiments). At the end of the treatment, conditioned medium was collected, proteolytic activity of tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA) was determined by zymography assays (A,D), and relative amount of proteolytic activity was determined by densitometric analysis (B,E). Cell viability was determined by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assays (C,F). Compared to low levels of uPA present in untreated cells or in norrin alone-treated cells (A,B), uPA levels were increased in SS (B, *p<0.05) or in SS and norrin-treated cells (B, **p<0.05) at 24 h after treatment. However, increased levels of uPA alone had no effect on cell survival (C, not significant, NS). Compared to low levels of uPA present in untreated cells or in norrin alone-treated cells (D,E), uPA (E, *p<.0.05, **p<0.05) and tPA (E, %p<0.05, %%p<0.05) levels were increased significantly in SS or in SS and norrin-treated cells at 48 h after treatment. Nonetheless, survival of RGC-5 cells decreased in SS alone-treated cells (F, *p<0.05) but not in SS and norrin-treated cells (F,**p<0.05).