Figure 4. Effect of transforming growth
factor (TGF)-β2 on activation of Smad2/3 in optic nerve head (ONH)
astrocytes and lamina cribrosa (LC) cells. ONH astrocytes and LC cells
were incubated with recombinant TGF-β2 (5 ng/ml) for 0, 15, 30, 60, and
120 min. A: Cell lysates were analyzed for phosphorylated
Smad3, total Smad3, phosphorylated Smad2, Smad2, and actin. B:
ONH astrocytes and LC cells were treated with or without TGF-β2 for 30
min, 60 min, and 120 min, and total cell lysates were also examined for
phosphorylated extracellular signal-regulated kinases (ERK)1/2, total
ERK1/2, phosphorylated p38, total p38, phosphorylated c-Jun N-terminal
kinases (JNK)1/2, total JNK1/2, and actin. Recombinant TGF-β2 increased
phosphorylation of Smad3 and Smad2 in ONH astrocytes as well as Smad3
phosphorylation in LC cells at 15 min, 30 min, 60 min and 120 min but
did not alter phosphorylation ERK, p38, and JNK1/2 in ONH astrocytes
and LC cells. These signaling proteins were detected at expected
molecular sizes.