title: 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.
authors.affiliation: Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Masaomi
authors.initials: M
authors.lastname: Koyanagi
authors.forename: Jun
authors.initials: J
authors.lastname: Takahashi
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Arakawa
authors.forename: Daisuke
authors.initials: D
authors.lastname: Doi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Fukuda
authors.forename: Hideki
authors.initials: H
authors.lastname: Hayashi
authors.forename: Shuh
authors.initials: S
authors.lastname: Narumiya
authors.forename: Nobuo
authors.initials: N
authors.lastname: Hashimoto
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D015153:Blotting, Western; D053595:Embryonic Stem Cells / Q000378:metabolism / Q000473:pathology*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D020287:In Situ Nick-End Labeling; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000378:metabolism / Q000473:pathology*; D015398:Signal Transduction / Q000502:physiology*; D033581:Stem Cell Transplantation; D020741:rho GTP-Binding Proteins / Q000378:metabolism*