Genotoxic Stress Abrogates Renewal of Melanocyte Stem Cells by Triggering Their Differentiation

SummarySomatic stem cell depletion due to the accumulation of DNA damage has been implicated in the appearance of aging-related phenotypes. Hair graying, a typical sign of aging in mammals, is caused by the incomplete maintenance of melanocyte stem cells (MSCs) with age. Here, we report that irreparable DNA damage, as caused by ionizing radiation, abrogates renewal of MSCs in mice. Surprisingly, the DNA-damage response triggers MSC differentiation into mature melanocytes in the niche, rather than inducing their apoptosis or senescence. The resulting MSC depletion leads to irreversible hair graying. Furthermore, deficiency of Ataxia-telangiectasia mutated (ATM), a central transducer kinase of the DNA-damage response, sensitizes MSCs to ectopic differentiation, demonstrating that the kinase protects MSCs from their premature differentiation by functioning as a “stemness checkpoint” to maintain the stem cell quality and quantity

チイキ レンケイ ニヨル ショネンジ キョウイク プログラム ノ ジッセンテキ ケンキュウ : ガクセイ ニヨル チイキ プロモーションビデオ セイサク

This research aims to develop a new program for first year education with a view to cultivating students\u27 abilities to work in groups, to conduct case studies, and to analyze and present their findings in a creative way. In this program, each group was assigned a case study of an NPO in Himeji area. Five or six students work in a group and conduct research on the target organization. They interviewed NPO workers and participate in social activities to deepen their understanding of the organization. In the end, each group shared the result of the study through powerpoint presentations and short films. Survey was conducted to analyze the responses of both students and local NPO workers to this educational experiment. The survey shows that this program contributed developing students\u27 interests in social activities. NPO workers also evaluated this attempt positively as an approach to co-develop project-based learning that could offer merits both for students and NPOs

Genotoxic stress abrogates renewal of melanocyte stem cells by triggering their differentiation.

金沢大学医薬保健研究域　医学系Somatic stem cell depletion due to the accumulation of DNA damage has been implicated in the appearance of aging-related phenotypes. Hair graying, a typical sign of aging in mammals, is caused by the incomplete maintenance of melanocyte stem cells (MSCs) with age. Here, we report that irreparable DNA damage, as caused by ionizing radiation, abrogates renewal of MSCs in mice. Surprisingly, the DNA-damage response triggers MSC differentiation into mature melanocytes in the niche, rather than inducing their apoptosis or senescence. The resulting MSC depletion leads to irreversible hair graying. Furthermore, deficiency of Ataxia-telangiectasia mutated (ATM), a central transducer kinase of the DNA-damage response, sensitizes MSCs to ectopic differentiation, demonstrating that the kinase protects MSCs from their premature differentiation by functioning as a "stemness checkpoint" to maintain the stem cell quality and quantity. © 2009 Elsevier Inc. All rights reserved