Induced pluripotent stem cells (iPSCs) outwardly appear to be indistinguishable from embryonic stem cells (ESCs). A study of gene expression profiles of mouse and human ESCs and iPSCs suggests that, while iPSCs are quite similar to their embryonic counterparts, a recurrent gene expression signature appears in iPSCs regardless of their origin or the method by which they were generated. Upon extended culture, hiPSCs adopt a gene expression profile more similar to hESCs; however, they still retain a gene expression signature unique from hESCs that extends to miRNA expression. Genome-wide data suggested that the iPSC signature gene expression differences are due to differential promoter binding by the reprogramming factors. High-resolution array profiling demonstrated that there is no common specific subkaryotypic alteration that is required for reprogramming and that reprogramming does not lead to genomic instability. Together, these data suggest that iPSCs should be considered a unique subtype of pluripotent cell.
Bibliographical noteFunding Information:
M.H.C. is supported by the USHHS Ruth L. Kirschstein Institutional (NRSA #T32 CA009056) and G.A. by NIH/NICHHD 5 K12 HD001281. S.V. is supported by Regione Emilia Romagna PRRIITT Biopharmanet. C.M.C. is supported by NIH-NCI. M.A.T. is supported by NIH and CIRM Grant RS1-00313. M.G. is supported by NIH GM23674. N.B. is supported by the Legacy Heritage Fund. K.P. is supported by the V and Kimmel Scholar Foundations, the NIH Director's Young Innovator Award (DP2 OD001686-01), and a CIRM Young Investigator Award (RN1-00564-1). W.E.L. holds the Maria Rowena Ross Term Chair in Cell Biology and Biochemistry and is supported by CIRM #RS1-00259-1, and the Basil O'Connor Starter Scholar Award from The March of Dimes. This work was also supported by the CIRM New Cell Line grant to Jerome Zack (UCLA), W.E.L., and K.P. (RL1-00681-1). A.T.C., A.D.P., K.P., and M.A.T. are also supported by NIH P01 GM081621-01A1.