Effect of lentiviral shRNA of Nogo receptor on rat cortex neuron axon outgrowth.

BACKGROUND AND AIMS Axon growth is crucial for injured neural tissue to recover; however it is difficult to achieve in general. Axon outgrowth is inhibited by the activation of the Nogo receptor (NgR) by one of three different ligands. The present study aimed to suppress the inhibitory effect of the three inhibitory proteins to facilitate axon outgrowth. METHODS A lentiviral vector, siNgR199 (that has the capacity to interfere with the gene of NgR expression), was constructed for suppressing the gene transcription of NgR. Rat cortex neurons and oligodendrocytes were prepared to observe the effect of siNgR199 on facilitating axon outgrowth. RESULTS After transfection, the lentiviral siRNA of NgR remained in target neurons for almost two weeks whereas the conventional siRNA of NgR remained in neurons less than five days. Lentivirus-mediated delivery of exogenous small interfering RNA (siNgR199) targeting NgR significantly reduced the expression of this receptor and promoted axon outgrowth. In contrast, provision of naked siRNA targeting NgR (NgRsiRNA) showed less inhibitory effect on NgR protein expression and did not affect axon outgrowth. CONCLUSIONS Lentiviral siRNA of NgR effectively suppresses the expression of NgR in cultured neurons that facilitates the axon outgrowth. The data implicate that lentiviral siRNA of NgR has therapeutic potential in facilitating the recovery of injured neural tissue.