title: Regulation of c-Myc Expression by Ahnak Promotes Induced Pluripotent Stem Cell Generation.
abstract: We have previously reported that Ahnak-mediated TGFβ signaling leads to down-regulation of c-Myc expression. Here, we show that inhibition of Ahnak can promote generation of induced pluripotent stem cells (iPSC) via up-regulation of endogenous c-Myc. Consistent with the c-Myc inhibitory role of Ahnak, mouse embryonic fibroblasts from Ahnak-deficient mouse (Ahnak(-/-) MEF) show an increased level of c-Myc expression compared with wild type MEF. Generation of iPSC with just three of the four Yamanaka factors, Oct4, Sox2, and Klf4 (hereafter 3F), was significantly enhanced in Ahnak(-/-) MEF. Similar results were obtained when Ahnak-specific shRNA was applied to wild type MEF. Of note, expressionof Ahnak was significantly induced during the formation of embryoid bodies from embryonic stem cells, suggesting that Ahnak-mediated c-Myc inhibition is involved in embryoid body formation and the initial differentiation of pluripotent stem cells. The iPSC from 3F-infected Ahnak(-/-) MEF cells (Ahnak(-/-)-iPSC-3F) showed expression of all stem cell markers examined and the capability to form three primary germ layers. Moreover, injection of Ahnak(-/-)-iPSC-3F into athymic nude mice led to development of teratoma containing tissues from all three primary germ layers, indicating that iPSC from Ahnak(-/-) MEF are bona fide pluripotent stem cells. Taken together, these data provide evidence for a new role for Ahnak in cell fate determination during development and suggest that manipulation of Ahnak and the associated signaling pathway may provide a means to regulate iPSC generation.
authors.affiliation: From the Department of Life Sciences, Ewha Womans University, Seoul 120-750, Korea.
authors.forename: Hee Jung
authors.initials: HJ
authors.lastname: Lim
authors.affiliation: From the Department of Life Sciences, Ewha Womans University, Seoul 120-750, Korea.
authors.forename: Jusong
authors.initials: J
authors.lastname: Kim
authors.affiliation: the Graduate School of Biomedical Science and Engineering, Department of Biomedical Science, Hanyang University, Seoul 133-791, Korea, and.
authors.forename: Chang-Hwan
authors.initials: CH
authors.lastname: Park
authors.affiliation: the Soonchunhyang Institute of Medi-bioscience, Soon Chun Hyang University, Cheonan 31538, Korea.
authors.forename: Sang A
authors.initials: SA
authors.lastname: Lee
authors.affiliation: the Soonchunhyang Institute of Medi-bioscience, Soon Chun Hyang University, Cheonan 31538, Korea.
authors.forename: Man Ryul
authors.initials: MR
authors.lastname: Lee
authors.affiliation: the Graduate School of Biomedical Science and Engineering, Department of Biomedical Science, Hanyang University, Seoul 133-791, Korea, and.
authors.forename: Kye-Seong
authors.initials: KS
authors.lastname: Kim
authors.affiliation: From the Department of Life Sciences, Ewha Womans University, Seoul 120-750, Korea, jkim1964@ewha.ac.kr.
authors.forename: Jaesang
authors.initials: J
authors.lastname: Kim
authors.affiliation: From the Department of Life Sciences, Ewha Womans University, Seoul 120-750, Korea, baeys@ewha.ac.kr.
authors.forename: Yun Soo
authors.initials: YS
authors.lastname: Bae
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D065150:Cellular Reprogramming; D015536:Down-Regulation; D058732:Embryoid Bodies / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D005786:Gene Expression Regulation; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000378:metabolism* / Q000473:pathology; D000090062:Kruppel-Like Factor 4; D008297:Male; D008565:Membrane Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D000066450:Mouse Embryonic Stem Cells / Q000378:metabolism; D009363:Neoplasm Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics* / Q000378:metabolism; D013724:Teratoma / Q000473:pathology
chemical_list: C075176:AHNAK protein, human; C489572:Ahnak protein, mouse; C000715467:KLF4 protein, human; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D016271:Proto-Oncogene Proteins c-myc
keywords: Myc (c-Myc); development; differentiation; embryonic stem cell; induced pluripotent stem cell (iPS cell) (iPSC)