Open Access5‐Aminoimidazole‐4‐carboxyamide Ribonucleoside Induces G 1 /S Arrest and Nanog Downregulation via p53 and Enhances Erythroid Differentiation
Author(s) -
Chae HeeDon,
Lee ManRyul,
Broxmeyer Hal E.
Publication year - 2012
Publication title -
stem cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.159
H-Index - 229
eISSN - 1549-4918
pISSN - 1066-5099
DOI - 10.1002/stem.778
Subject(s) - homeobox protein nanog , biology , mg132 , microbiology and biotechnology , embryonic stem cell , rex1 , nanog homeobox protein , cellular differentiation , leukemia inhibitory factor , gata1 , stem cell , induced pluripotent stem cell , biochemistry , proteasome , proteasome inhibitor , haematopoiesis , gene
Molecular mechanisms of how energy metabolism affects embryonic stem cell (ESC) pluripotency remain unclear. AMP‐activated protein kinase (AMPK), a key regulator for controlling energy metabolism, is activated in response to ATP‐exhausting stress. We investigated whether cellular energy homeostasis is associated with maintenance of self‐renewal and pluripotency in mouse ESCs (mESCs) by using 5‐aminoimidazole‐4‐carboxyamide ribonucleoside (AICAR) as an activator of AMPK. We demonstrate that AICAR treatment activates the p53/p21 pathway and markedly inhibits proliferation of R1 mESCs by inducing G 1 /S‐phase cell cycle arrest, without influencing apoptosis. Treatment with AICAR also significantly reduces pluripotent stem cell markers, Nanog and stage‐specific embryonic antigen‐1, in the presence of leukemia inhibitory factor, without affecting expression of Oct4. H9 human ESCs also responded to AICAR with induction of p53 activation and repression of Nanog expression. AICAR reduced Nanog mRNA levels in mESCs transiently, an effect not due to expression of miR‐134 which can suppress Nanog expression. AICAR induced Nanog degradation, an effect inhibited by MG132, a proteasome inhibitor. Although AICAR reduced embryoid body formation from mESCs, it increased expression levels of erythroid cell lineage markers ( Ter119 , GATA1 , Klf1 , Hbb‐b , and Hbb‐bh1 ). Although erythroid differentiation was enhanced by AICAR, endothelial lineage populations were remarkably reduced in AICAR‐treated cells. Our results suggest that energy metabolism regulated by AMPK activity may control the balance of self‐renewal and differentiation of ESCs. S TEM C ELLS 2012; 30:140–149.