Arhgef1 is expressed in cortical neural progenitor cells and regulates neurite outgrowth of newly differentiated neurons.

Neurite outgrowth is crucial for the maturation of neurons and the establishment of anatomical connections during development of the nervous system. We report here that Arhgef1, a RhoA guanine nucleotide exchange factor previously found expressed in the early stages of neuronal development to regulate neurite outgrowth, is also highly expressed in cortical neural progenitor cells (NPCs). To better dissect its role in NPCs, we knocked down Arhgef1 expression in these cells and induced differentiated of them into neurons. Notably, silencing of Arhgef1 markedly enhanced neurite outgrowth in neurons derived from NPCs. Furthermore, we showed that Arhgef1 silencing inhibited the activity of RhoA, and pharmacological blockade of RhoA activity promoted neurite outgrowth in NPC-derived neurons. These findings reveal that Arhgef1 controls the process of neurite formation in newborn cortical neurons derived from NPCs.