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08:36
Generation of Integration-free Human Induced Pluripotent Stem Cells Using Hair-derived Keratinocytes
Published on: August 20, 2015
Human hair genealogies and stem cell latency
Jung Yeon Kim1, Simon Tavaré, Darryl Shibata
1Department of Pathology, University of Southern California Keck School of Medicine, Los Angeles, CA 90033, USA. pck2973@unitel.co.kr
BMC Biology
|February 7, 2006
Summary
Human stem cell division rates can be estimated by measuring replication errors. Hair stem cells divide infrequently, suggesting a slower aging process compared to other tissues like the intestine.
Area of Science:
- Stem cell biology
- Epigenetics
- Human aging
Background:
- Stem cells self-renew and produce differentiated cells.
- Measuring stem cell division frequency is challenging.
- Replication errors, like epigenetic methylation, can indicate division history.
Purpose of the Study:
- To develop a method for measuring stem cell division rates using epigenetic errors.
- To investigate stem cell division patterns in human hair follicles.
Main Methods:
- Epigenetic errors (methylation) were measured in CpG-rich molecular clocks within human hairs.
- Hair growth and replacement cycles were considered to assess error accumulation.
- Replication errors were analyzed in relation to hair length and age.
Main Results:
- Average hair methylation errors increased up to age two, then plateaued.
- This pattern suggests infrequent division of bulge stem cells in hair follicles.
- Longer hairs showed more errors, consistent with mitotic follicle cells.
Conclusions:
- Hair stem cells appear to have a slower rate of division and aging compared to intestinal stem cells.
- Epigenetic molecular clocks in hair suggest a 'restart' mechanism with each new hair cycle.
- Stem cell latency and error accumulation vary significantly across different human tissues.
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