Effect of Y-27632 on the cultured retinal neurocytes of rats

Y-27632 Induces Neurite Outgrowth by Activating the NOX1-Mediated AKT and PAK1 Phosphorylation Cascades in PC12 Cells

Y-27632 is known as a selective Rho-associated coiled coil-forming kinase (ROCK) inhibitor. Y-27632 has been shown to induce neurite outgrowth in several neuronal cells. However, the precise molecular mechanisms linking neurite outgrowth to Y-27632 are not completely understood. In this study, we examined the ability of Y-27632 to induce neurite outgrowth in PC12 cells and evaluated the signaling cascade. The effect of Y-27632 on the neurite outgrowth was inhibited by reactive oxygen species (ROS) scavengers such as N-acetyl cysteine (NAC) and trolox. Furthermore, Y-27632-induced neurite outgrowth was not triggered by NADPH oxidase 1 (NOX1) knockdown or diphenyleneiodonium (DPI), a NOX inhibitor. Suppression of the Rho-family GTPase Rac1, which is under the negative control of ROCK, with expression of the dominant negative Rac1 mutant (Rac1N17) prevented Y-27632-induced neurite outgrowth. Moreover, the Rac1 inhibitor NSC23766 prevented Y-27632-induced AKT and p21-activated kinase 1 (PAK1) activation. AKT inhibition with MK2206 suppressed Y-27632-induced PAK1 phosphorylation and neurite outgrowth. In conclusion, our results suggest that Rac1/NOX1-dependent ROS generation and subsequent activation of the AKT/PAK1 cascade contribute to Y-27632-induced neurite outgrowth in PC12 cells.

ROCK inhibition enhances neurite outgrowth in neural stem cells by upregulating YAP expression in vitro

Spontaneous axonal regeneration of neurons does not occur after spinal cord injury because of inhibition by myelin and other inhibitory factors. Studies have demonstrated that blocking the Rho/Rho-kinase (ROCK) pathway can promote neurite outgrowth in spinal cord injury models. In the present study, we investigated neurite outgrowth and neuronal differentiation in neural stem cells from the mouse subventricular zone after inhibition of ROCK in vitro. Inhibition of ROCK with Y-27632 increased neurite length, enhanced neuronal differentiation, and upregulated the expression of two major signaling pathway effectors, phospho-Akt and phospho-mitogen-activated protein kinase, and the Hippo pathway effector YAP. These results suggest that inhibition of ROCK mediates neurite outgrowth in neural stem cells by activating the Hippo signaling pathway.