Integration-deficient lentiviral vectors encoding an shRNA targeting LINGO-1 do not enhance neurite outgrowth. (A) The neurite length of beta-III tubulin positive CGNs was measured, divided by the total number of neurons and the mean neurite length per neuron plotted. CGNs plated on the CHO-R2 cells had significantly longer neurites compared to CGNs plated on the inhibitory CHO-MAG cells (*** P < 0.001). CHO-MAG inhibition could be partially reversed with using 50 μM Y 27632 (*** P < 0.001). Lenti-LINGO1-sh4 did not significantly increase neurite outgrowth of CGNs plated on an inhibitory MAG substrate compared to the control lentiviral vectors or the NVC (P > 0.05). Values represent mean and SEM, analysis was performed using one way ANOVA, with Dunnett’s post-hoc tests comparing to CHO-MAG cells, P < 0.001, n = 8/group. (B) CGN neurite outgrowth is inhibited by CHO-MAG cells. (C) Transduction with Lenti-LINGO1-sh4 does not alleviate the MAG inhibition and enhance CGN neurite outgrowth. (D) The ROCK inhibitor Y-27632 partially reverses the MAG inhibition and promotes neurite outgrowth. Scale bar: 100 μm.