title: DNA methylation dynamics in human induced pluripotent stem cells.
abstract: Indeed human induced pluripotent stem cells (hiPSCs) are considered to be powerful tools in regenerative medicine. To enable the use of hiPSCs in the field of regenerative medicine, it is necessary to understand the mechanisms of reprogramming during the transformation of somatic cells into hiPSCs. Genome-wide epigenetic modification constitutes a critical event in the generation of iPSCs. In other words, to analyze epigenetic changes in iPSCs means to elucidate reprogramming processes. We have established a large number of hiPSCs derived from various human tissues and have obtained their DNA methylation profiles. Comparison analyses indicated that the epigenetic patterns of various hiPSCs, irrespective of their source tissue, were very similar to one another and were similar to those of human embryonic stem cells (hESCs). However, the profiles of hiPSCs and hESCs exhibited epigenetic differences, which were caused by random aberrant hypermethylation at early passages. Interestingly, continuous passaging of the hiPSCs diminished the differences between DNA methylation profiles of hiPSCs and hESCs. The number of aberrant DNA methylation regions may thus represent a useful epigenetic index for evaluating hiPSCs in the context of therapeutic applications.
authors.affiliation: Laboratory of Veterinary Biochemistry and Molecular Biology, Graduate School of Medicine and Veterinary Medicine, Faculty of Agriculture, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki, 889-2192, Japan. aknishino@cc.miyazaki-u.ac.jp.|Center for Animal Disease Control, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki, 889-2192, Japan. aknishino@cc.miyazaki-u.ac.jp.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Nishino
authors.affiliation: Department of Reproductive Biology, Center for Regenerative Medicine, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Umezawa
mesh_terms: D065150:Cellular Reprogramming / Q000235:genetics*; D019175:DNA Methylation / Q000235:genetics; D044127:Epigenesis, Genetic; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology*; D044968:Regenerative Medicine
keywords: DNA methylation; Epigenetics; Human induced pluripotent stem cells; Reprogramming