Inhibition of the Rho/ROCK pathway reduces apoptosis during transplantation of embryonic stem cell‐derived neural precursors

Abstract

Rho-GTPase has been implicated in the apoptosis of many cell types, including neurons, but the mechanism by which it acts is not fully understood. Here, we investigate the roles of Rho and ROCK in apoptosis during transplantation of embryonic stem cell-derived neural precursor cells. We find that dissociation of neural precursors activates Rho and induces apoptosis. Treatment with the Rho inhibitor C3 exoenzyme and/or the ROCK inhibitor Y-27632 decreases the amount of dissociation-induced apoptosis (anoikis) by 20-30%. Membrane blebbing, which is an early morphological sign of apoptosis; cleavage of caspase-3; and release of cytochrome c from the mitochondria are also reduced by ROCK inhibition. These results suggest that dissociation of neural precursor cells elicits an intrinsic pathway of cell death that is at least partially mediated through the Rho/ROCK pathway. Moreover, in an animal transplantation model, inhibition of Rho and/or ROCK suppresses acute apoptosis of grafted cells. After transplantation, tumor necrosis factor-alpha and pro-nerve growth factor are strongly expressed around the graft. ROCK inhibition also suppresses apoptosis enhanced by these inflammatory cytokines. Taken together, these results indicate that inhibition of Rho/ROCK signaling may improve survival of grafted cells in cell replacement therapy.

Rho/ROCK pathway is essential to the expansion, differentiation, and morphological rearrangements of human neural stem/progenitor cells induced by lysophosphatidic acid

“…The ROCK inhibitor Y27632 signifi cantly increases hESC single-cell survival ( 62,63 ) and NS/PCs following neurosphere dissociation ( 64 ). Further, upon dissociation to single cells, the Rho/ ROCK pathway is activated and responsible for modulating cell-cell contact-induced apoptosis in hESCs ( 65 ), NS/PCs ( 64 ), and neurons ( 66 ), an effect associated with MLC phosphorylation in hESCs ( 47 ).…”

The Rho Kinases: Critical Mediators of Multiple Profibrotic Processes and Rational Targets for New Therapies for Pulmonary Fibrosis

“…This process requires the proliferation of epithelial precursors, which may be inhibited by ROCK signaling. ROCK signaling impairs the survival of embryonic or induced pluripotent stem cells (Watanabe et al, 2007;Koyanagi et al, 2008;Li et al, 2008;Gauthaman et al, 2010;Horani et al, 2013), and this effect appears to extend to epithelial cell progenitors in the lung as well. ROCK inhibition has been shown to enhance basal cell proliferation in cultured human tracheobronchial and mouse tracheal epithelial cells (Horani et al, 2013).…”

The Rho Kinase Pathway Regulates Mouse Adult Neural Precursor Cell Migration

“…In other neural stem cell systems, ROCK inhibition has been shown to affect survival and differentiation. Under conditions that induce apoptosis, ROCK inhibition can promote NPC survival, such as following transplantation of embryonic stem (ES) cell-derived NPCs [62]. In human ES cell-derived neural stem cells, it also promotes differentiation into neural crest-like cells [63] and blocks lysophosphatidic acid (LPA)-induced inhibition of neuronal differentiation, with no effect on neuronal differentiation by itself [64].…”