Fig. 3. Activation of neurotrophin signaling is able to overcome the inhibitory effect of aggrecan on axon assembly from PCL neurons. (A,B) Laminin-induced axon assembly from PCL neurons (A) was markedly inhibited by aggrecan (B). (C) Addition of NGF overcame the inhibitory effect of aggrecan on axon assembly from PCL neurons. Magnification, 4x. (D,E) Quantification of the stimulatory effect of NGF on axon assembly from PCL neurons cultured on aggrecan. Note that the rescue effect of NGF depends on the activities of TrkA and PI3K, mediators of the NGF signaling, but is independent of integrin signaling and transcription (E). *P<0.0001 vs control; **P<0.0001 between indicated groups in D, and vs LM+NGF+Agg. in E. ^#P<0.01 vs LM+NGF+Agg. in D and E. DRB, transcription inhibitor; K252a, TrkA inhibitor; LY, LY 294002 PI 3-kinase inhibitor.