Focus: Thrombopoietin-Increased DNA-PK-Dependent DNA Repair Limits Hematopoietic Stem and Progenitor Cell Mutagenesis in Response to DNA Damage

Abstract

DNA double-strand breaks (DSBs) represent a serious threat for hematopoietic stem cells (HSCs). How cytokines and environmental signals integrate the DNA damage response and contribute to HSC-intrinsic DNA repair processes remains unknown. Thrombopoietin (TPO) and its receptor, Mpl, are critical factors supporting HSC self-renewal and expansion. Here, we uncover an unknown function for TPO-Mpl in the regulation of DNA damage response. We show that DNA repair following γ-irradiation (γ-IR) or the action of topoisomerase-II inhibitors is defective in Mpl(-/-) and in wild-type mouse or human hematopoietic stem and progenitor cells treated in the absence of TPO. TPO stimulates DNA repair in vitro and in vivo by increasing DNA-PK-dependent nonhomologous end-joining efficiency. This ensures HSC chromosomal integrity and limits their long-term injury in response to IR. This shows that niche factors can modulate the HSC DSB repair machinery and opens new avenues for administration of TPO agonists for minimizing radiotherapy-induced HSC injury and mutagenesis.

Source: Thrombopoietin-Increased DNA-PK-Dependent DNA Repair Limits Hematopoietic Stem and Progenitor Cell Mutagenesis in Response to DNA Damage. de Laval B, Pawlikowska P, Petit-Cocault L, Bilhou-Nabera C, Aubin-Houzelstein G, Souyri M, Pouzoulet F, Gaudry M, Porteu F (francoise.porteu@inserm.fr). Cell Stem Cell. 2013 Jan 3;12(1):37-48.

Free paper available at:

http://download.cell.com/cell-stem-cell/pdf/PIIS1934590912006352.pdf?intermediate=true