Expectations of Epigenetic Research Studies Focusing on Mesenchymal Stem Cells

Epigenetic alternations are not associated with any changing the base sequence of DNA, but are closely related to phenome together with genome [1]. Most of them are determined differvvently under various external and internal influences and, even if abnormal, memorized over individual life. In the ontogeny that starts from a totipotent stem cell such as a fertilized egg, the epigenetic alternations occur in good order along with cell differentiation process toward peculiar epigenetic patterns of individual cell series. In contrast, a reverse artificial phenomenon induced by transduction of 4 genes, Oct3/4, Sox2, Klf4 and c-Myc (induced progenitor and stem cells: iPS cells) is known to accompany with significant abnormalities of DNA methylations, one of the epigenetic regulation mechanisms, fearing possible abnormal cell development. These cells should be used for elucidation of unknown reprogramming mechanisms rather than rough- and ready-clinical applications.