Wild-type and SAMP8 mice show age-dependent changes in distinct stem cell compartments of the interfollicular epidermis

PLoS One. 2019 May 15;14(5):e0215908. doi: 10.1371/journal.pone.0215908. eCollection 2019.

Abstract

Delayed wound healing and reduced barrier function with an increased risk of cancer are characteristics of aged skin and one possible mechanism is misregulation or dysfunction of epidermal stem cells during aging. Recent studies have identified heterogeneous stem cell populations within the mouse interfollicular epidermis that are defined by territorial distribution and cell division frequency; however, it is unknown whether the individual stem cell populations undergo distinct aging processes. Here we provide comprehensive characterization of age-related changes in the mouse epidermis within the specific territories of slow-cycling and fast-dividing stem cells using old wild-type, senescence-accelerated mouse prone 1 (SAMP1) and SAMP8 mice. During aging, the epidermis exhibits structural changes such as irregular micro-undulations and overall thinning of the tissue. We also find that, in the old epidermis, proliferation is preferentially decreased in the region where fast-dividing stem cells reside whereas the lineage differentiation marker appears to be more affected in the slow-cycling stem cell region. Furthermore, SAMP8, but not SAMP1, exhibits precocious aging similar to that of aged wild-type mice, suggesting a potential use of this model for aging study of the epidermis and its stem cells. Taken together, our study reveals distinct aging processes governing the two epidermal stem cell populations and suggests a potential mechanism in differential responses of compartmentalized stem cells and their niches to aging.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Differentiation
  • Cell Division
  • Cell Proliferation
  • Cellular Senescence
  • Epidermis / metabolism*
  • Mice
  • Species Specificity
  • Stem Cells / cytology*

Grant support

This work was supported by AMED-PRIME, AMED (JP18gm6110016), Grant-in-Aid for Scientific Research on Innovative Areas “Stem Cell Aging and Disease” (17H05631), Grant-in-Aid for Research Activity Start-up (16H06660), Grant-in-Aid for Early-Career Scientists (18K14709) to A.S., and research grants from The Nakajima Foundation, The Uehara Memorial Foundation, Inamori Foundation, Astellas Foundation for Research on Metabolic Disorders, The Takeda Foundation, Leave a Nest Co., ltd. for IKEDARIKA award, and Basic Research Support Program Type A from the University of Tsukuba to A.S. This study was partially supported by the project of Japan Science and Technology Agency (JST), Science and Technology Research Partnership for Sustainable Development (SATREPS) (JPMJSA1506) to H. I. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.