Epigenetic analysis of cellular senescence using the technology for reprogramming cells

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K06900
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Genome biology
• Research Institution: Keio University
• Principal Investigator: Miyoshi Hiroyuki 慶應義塾大学, 医学部(信濃町), 特任准教授 (70219830)
• Research Collaborator: YOSHIDA Naomi ; YO Masahiro
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 細胞老化 / リプログラミング / エピゲノム

Outline of Final Research Achievements

We asked whether iPS cells could be generated from replicatively senescent human fibroblasts. We were not able to generate iPS cells with the four Yamanaka reprogramming factors (Oct3/4, Sox2, Klf4, and c-Myc). However, we succeeded in generation of iPS cells, albeit with extremely low efficiency, using lentiviral vectors expressing the four factors plus Lin28 and non-integrating lentiviral vector for transient expression of SV40LT together with two chemical compounds targeting epigenetic enzymes. There was no difference between iPS cells from senescent cells and control iPS cells for cell growth and morphology up to passage 50 as well as global gene expression profiles, DNA methylation status, and histone modifications. There was also no difference for cellular senescence of fibroblasts differentiated from iPS cells. These results indicate that cellular senescence caused by epigenetic changes can be rejuvenated by reprogramming.

Free Research Field

細胞生物学

Academic Significance and Societal Importance of the Research Achievements

細胞老化は、DNA損傷、酸化ストレス、がん遺伝子発現などのストレスによって誘導され、不可逆的に細胞分裂が停止する現象であるが、その分子機構はまだ不明な点が多い。本研究では、分裂能を完全に失い老化した正常ヒト線維芽細胞から、非常に低い頻度ではあるがiPS細胞を樹立することができた。このことから、エピジェネティックな変化によって細胞は老化するが、リプログラミングによってエピジェネティックな変化はリセットでき、分裂停止した老化細胞は若返ることができると考えられる。