Molecular pathway and cell state responsible for dissociation-induced apoptosis in human pluripotent stem cells.
Human embryonic stem cells (hESCs), unlike mouse ones (mESCs), are vulnerable to apoptosis upon dissociation. Here, we show that the apoptosis, which is of a nonanoikis type, is caused by ROCK-dependent hyperactivation of actomyosin and efficiently suppressed by the myosin inhibitor Blebbistatin. The actomyosin hyperactivation is triggered by the loss of E-cadherin-dependent intercellular contact and also observed in dissociated mouse epiblast-derived pluripotent cells but not in mESCs. We reveal that Abr, a unique Rho-GEF family factor containing a functional Rac-GAP domain, is an indispensable upstream regulator of the apoptosis and ROCK/myosin hyperactivation. Rho activation coupled with Rac inhibition is induced in hESCs upon dissociation, but not in Abr-depleted hESCs or mESCs. Furthermore, artificial Rho or ROCK activation with Rac inhibition restores the vulnerability of Abr-depleted hESCs to dissociation-induced apoptosis. Thus, the Abr-dependent "Rho-high/Rac-low" state plays a decisive role in initiating the dissociation-induced actomyosin hyperactivation and apoptosis in hESCs.
Ohgushi
Masatoshi
M
Organogenesis and Neurogenesis Group, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan.
Matsumura
Michiru
M
Eiraku
Mototsugu
M
Murakami
Kazuhiro
K
Aramaki
Toshihiro
T
Nishiyama
Ayaka
A
Muguruma
Keiko
K
Nakano
Tokushige
T
Suga
Hidetaka
H
Ueno
Morio
M
Ishizaki
Toshimasa
T
Suemori
Hirofumi
H
Narumiya
Shuh
S
Niwa
Hitoshi
H
Sasai
Yoshiki
Y
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015820:Cadherins / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D053595:Embryonic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000378:metabolism; D005855:Germ Layers / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D006801:Humans; D051379:Mice; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009218:Myosins / Q000378:metabolism; D039904:Pluripotent Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D020744:rac GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D054460:rho-Associated Kinases / Q000378:metabolism
C082659:ABR protein, human; D015820:Cadherins; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D054460:rho-Associated Kinases; D009218:Myosins; D020744:rac GTP-Binding Proteins; D002118:Calcium