PTEN inhibition enhances neurite outgrowth in human embryonic stem cell-derived neuronal progenitor cells

ABSTRACT We investigated the role of PTEN (phosphatase and tensin homolog deleted on chromosome 10) during neurite outgrowth of human embryonic stem cell (hESC)‐derived neuronal progenitors. PTEN inhibits phosphoinositide 3‐kinase (PI3K)/Akt signaling, a common and central outgrowth and survival pathway downstream of neuronal growth factors. It is known that PTEN inhibition, by either polymorphic mutation or gene deletion, can lead to the development of tumorigenesis (Stambolic et al., ; Tamura et al., ). However, temporary inhibition of PTEN, through pharmacological manipulation, could regulate signaling events such as the PI3K/Akt signaling pathway, leading to enhanced recovery of central nervous system (CNS) injury and disease. We demonstrate that pharmacological inhibition of PTEN in hESC‐derived neuronal progenitors significantly increased neurite outgrowth in vitro in a dose‐ and time‐dependent manner. Our results indicate that inhibition of PTEN augments neurite outgrowth beyond that of traditional methods such as elevation of intracellular cyclic adenosine monophosphate (cAMP) levels, and depends on upregulation of the PI3K/Akt signaling pathway and its downstream effectors, such as mammalian target of rapamycin (mTOR). PTEN inhibition also rescued neurite outgrowth over an inhibitory substrate in vitro. These findings indicate a remarkable impact on hESC‐derived neuronal progenitor plasticity through PTEN inhibition. Overall, these findings identify a novel therapeutic strategy for neurite outgrowth in CNS injury and disease. J. Comp. Neurol. 522:2741–2755, 2014. © 2014 Wiley Periodicals, Inc. The authors demonstrate that transient PTEN inhibition in hESC‐derived neuronal progenitors improved neurite outgrowth in vitro in both growth‐permissive and growth‐inhibitory environments, and could be used in the context of transplantation as a therapeutic strategy for addressing central nervous system injury and disease conditions characterized by the loss of neurons and connectivity.