Figure 6. Effect of HB-EGF on the secretion of VEGF by human Müller cells (MIO-M1)

A: MIO-M1 cells were preincubated in the absence or presence of blocking substances, and subsequently were stimulated with HB-EGF (50 ng/ml) for 6 h. VEGF concentration in the cultured media was measured by ELISA. The following substances were tested: inhibitors of receptor tyrosine kinases, AG1478 (300 nM) and AG1296 (10 μM); inhibitors of the activation of mitogen activated protein kinases, PD98059 (20 μM) and SB203580 (10 μM); inhibitor of the PI3K, LY294002 (5 μM). B: Effect of a neutralizing anti-HB-EGF antibody (5 μg/ml). Data are expressed as percentage of untreated control (100%) which was between 100 and 250 pg/ml. Each bars represents the mean of three independent experiments carried out in duplicate; error bars represent SEM. The asterisk indicates the bar is significantly different from the untreated control; the plus symbol represents a significant effect (p<0.05) of the blockers.