p21cip/WAF is a key regulator of long-term radiation damage in mesenchyme-derived tissues Academic Article uri icon


MeSH Major

  • Cell Differentiation
  • Cyclin-Dependent Kinase Inhibitor p21
  • Mesenchymal Stromal Cells
  • Radiation, Ionizing


  • This study aimed to determine the mechanisms responsible for long-term tissue damage following radiation injury. We irradiated p21-knockout (p21(-/-)) and wild-type (WT) mice and determined the long-term deleterious effects of this intervention on mesenchyme-derived tissues. In addition, we explored the mechanisms of radiation-induced mesenchymal stem cell (MSC) dysfunction in isolated bone marrow-derived cells. p21 expression was chronically elevated >200-fold in irradiated tissues. Loss of p21 function resulted in a >4-fold increase in the number of skin MSCs remaining after radiation. p21(-/-) mice had significantly less radiation damage, including 6-fold less scarring, 40% increased growth potential, and 4-fold more hypertrophic chondrocytes in the epiphyseal plate (P<0.01). Irradiated p21(-/-) MSCs had 4-fold increased potential for bone or fat differentiation, 4-fold greater proliferation rate, and nearly 7-fold lower senescence as compared to WT MSCs (P<0.01). Ectopic expression of p21 in knockout cells decreased proliferation and differentiation potential and recapitulated the WT phenotype. Loss of p21 function markedly decreases the deleterious effects of radiation injury in mesenchyme-derived tissues and preserves tissue-derived MSCs. In addition, p21 is a critical regulator of MSC proliferation, differentiation, and senescence both at baseline and in response to radiation.

publication date

  • December 2010



  • Academic Article



  • eng

Digital Object Identifier (DOI)

  • 10.1096/fj.10-155762

PubMed ID

  • 20720160

Additional Document Info

start page

  • 4877

end page

  • 88


  • 24


  • 12