title: Effect of high-dose irradiation on human bone-marrow-derived mesenchymal stromal cells.
abstract: Cell therapy using multipotent mesenchymal stromal cells (MSCs) is of high interest in various indications. As the pleiotropic effects mediated by MSCs rely mostly on their unique secretory profile, long-term persistence of ex-vivo-expanded cells in the recipient may not always be desirable. Irradiation is a routine procedure in transfusion medicine to prevent long-term persistence of nucleated cells and could therefore also be applied to MSCs. We have exposed human bone-marrow-derived MSCs to 30 or 60 Gy of γ-irradiation and assessed cell proliferation, clonogenicity, differentiation, cytokine levels in media supernatants, surface receptor profile, as well as expression of proto-oncogenes/cell cycle markers, self-renewal/stemness markers, and DNA damage/irradiation markers. Irradiated MSCs show a significant decrease in proliferation and colony-forming unit-fibroblasts. However, a subpopulation of surviving cells is able to differentiate, but is unable to form colonies after irradiation. Irradiated MSCs showed stable expression of CD73 and CD90 and absence of CD3, CD34, and CD45 during a 16-week follow-up period. We found increased vascular endothelial growth factor (VEGF) levels and a decrease of platelet-derived growth factor (PDGF)-AA and PDGF-AB/BB in culture media of nonirradiated cells. Irradiated MSCs showed an inverse pattern, that is, no increase of VEGF, and less consumption of PDGF-AA and PDGF-AB/BB. Interestingly, interleukin-6 (IL-6) levels increased during culture regardless of irradiation. Cells with lower sensitivity toward γ-irradiation showed positive β-galactosidase activity 10 days after irradiation. Gene expression of both irradiated and nonirradiated MSCs 13-16 weeks after irradiation with 60 Gy predominantly followed the same pattern; cell cycle regulators CDKN1A (p21) and CDKN2A (p16) were upregulated, indicating cell cycle arrest, whereas classical proto-oncogenes, respectively, and self-renewal/stemness markers MYC, TP53 (p53), and KLF4 were downregulated. In addition, DNA damage/irradiation markers ATM, ATR, BRCA1, CHEK1, CHEK2, MDC1, and TP53BP1 also mostly showed the same pattern of gene expression as high-dose γ-irradiation. In conclusion, we demonstrated the existence of an MSC subpopulation with remarkable resistance to high-dose γ-irradiation. Cells surviving irradiation retained their trilineage differentiation capacity and surface marker profile but changed their cytokine secretion profile and became prematurely senescent.
authors.affiliation: 1 Institut für Klinische Transfusionsmedizin und Immungenetik Ulm, DRK-Blutspendedienst Baden-Württemberg-Hessen, Universitätsklinikum Ulm , Ulm, Germany .
authors.forename: Natalie
authors.initials: N
authors.lastname: Fekete
authors.forename: Alexander
authors.initials: A
authors.lastname: Erle
authors.forename: Elisa Maria
authors.initials: EM
authors.lastname: Amann
authors.forename: Daniel
authors.initials: D
authors.lastname: Fürst
authors.forename: Markus Thomas
authors.initials: MT
authors.lastname: Rojewski
authors.forename: Alain
authors.initials: A
authors.lastname: Langonné
authors.forename: Luc
authors.initials: L
authors.lastname: Sensebé
authors.forename: Hubert
authors.initials: H
authors.lastname: Schrezenmeier
authors.forename: Gerlinde
authors.initials: G
authors.lastname: Schmidtke-Schrezenmeier
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology*; D002453:Cell Cycle / Q000528:radiation effects; D002454:Cell Differentiation / Q000528:radiation effects; D002462:Cell Membrane / Q000378:metabolism / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects; D016922:Cellular Senescence / Q000528:radiation effects; D002999:Clone Cells; D003114:Colony-Forming Units Assay; D016207:Cytokines / Q000378:metabolism; D004249:DNA Damage; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D006801:Humans; D000090062:Kruppel-Like Factor 4; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000528:radiation effects*; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D015415:Biomarkers; D016207:Cytokines; C000715467:KLF4 protein, human; D000090062:Kruppel-Like Factor 4