TY - JOUR
T1 - Reversible cell cycle inhibition and premature aging features imposed by conditional expression of p16Ink4a
AU - Boquoi, Amelie
AU - Arora, Sanjeevani
AU - Chen, Tina
AU - Litwin, Sam
AU - Koh, James
AU - Enders, Greg H.
N1 - Publisher Copyright:
© 2014 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.
PY - 2015/2/1
Y1 - 2015/2/1
N2 - The cyclin-dependent kinase (Cdk) inhibitor p16Ink4a (p16) is a canonical mediator of cellular senescence and accumulates in aging tissues, where it constrains proliferation of some progenitor cells. However, whether p16 induction in tissues is sufficient to inhibit cell proliferation, mediate senescence, and/or impose aging features has remained unclear. To address these issues, we generated transgenic mice that permit conditional p16 expression. Broad induction at weaning inhibited proliferation of intestinal transit-amplifying and Lgr5+ stem cells and rapidly imposed features of aging, including hair loss, skin wrinkling, reduced body weight and subcutaneous fat, an increased myeloid fraction in peripheral blood, poor dentition, and cataracts. Aging features were observed with multiple combinations of p16 transgenes and transactivators and were largely abrogated by a germline Cdk4 R24C mutation, confirming that they reflect Cdk inhibition. Senescence markers were not found, and de-induction of p16, even after weeks of sustained expression, allowed rapid recovery of intestinal cell proliferation and reversal of aging features in most mice. These results suggest that p16-mediated inhibition of Cdk activity is sufficient to inhibit cell proliferation and impose aging features in somatic tissues of mammals and that at least some of these aging features are reversible.
AB - The cyclin-dependent kinase (Cdk) inhibitor p16Ink4a (p16) is a canonical mediator of cellular senescence and accumulates in aging tissues, where it constrains proliferation of some progenitor cells. However, whether p16 induction in tissues is sufficient to inhibit cell proliferation, mediate senescence, and/or impose aging features has remained unclear. To address these issues, we generated transgenic mice that permit conditional p16 expression. Broad induction at weaning inhibited proliferation of intestinal transit-amplifying and Lgr5+ stem cells and rapidly imposed features of aging, including hair loss, skin wrinkling, reduced body weight and subcutaneous fat, an increased myeloid fraction in peripheral blood, poor dentition, and cataracts. Aging features were observed with multiple combinations of p16 transgenes and transactivators and were largely abrogated by a germline Cdk4 R24C mutation, confirming that they reflect Cdk inhibition. Senescence markers were not found, and de-induction of p16, even after weeks of sustained expression, allowed rapid recovery of intestinal cell proliferation and reversal of aging features in most mice. These results suggest that p16-mediated inhibition of Cdk activity is sufficient to inhibit cell proliferation and impose aging features in somatic tissues of mammals and that at least some of these aging features are reversible.
KW - Aging, Premature/pathology
KW - Animals
KW - Cell Cycle
KW - Cell Proliferation
KW - Cyclin-Dependent Kinase 4/metabolism
KW - Cyclin-Dependent Kinase Inhibitor p16/metabolism
KW - Epithelial Cells/cytology
KW - Humans
KW - Intestines/cytology
KW - Mice, Transgenic
KW - Reproducibility of Results
KW - Stem Cells/cytology
UR - http://www.scopus.com/inward/record.url?scp=84922624477&partnerID=8YFLogxK
UR - http://europepmc.org/abstract/med/25481981
U2 - 10.1111/acel.12279
DO - 10.1111/acel.12279
M3 - Article
C2 - 25481981
SN - 1474-9718
VL - 14
SP - 139
EP - 147
JO - Aging Cell
JF - Aging Cell
IS - 1
ER -