Brief report: A human induced pluripotent stem cell model of cernunnos deficiency reveals an important role for XLF in the survival of the primitive hematopoietic progenitors

Authors


  • Author contributions: K.T.: performed the majority of experiments, data collection and analysis, contribution to manuscript writing, and final approval of manuscript; I.N., J.E., G.S., and C.S.: performed some of the experiments and final approval of manuscript; J.Y.A.: provided important reagents for this work, performed some of the experiments, and final approval of manuscript; V.G.: provided important reagents for this work and final approval of manuscript; A.G.: conception and design of the study, provided important reagents for this work, and final approval of manuscript; S.P.: performed some of the experiments, collection and analysis of the data, contributed to manuscript writing, and final approval of manuscript; M.S. and L.A.: conception and design, manuscript writing, fund raising, and final approval of manuscript; P.J.: provided reagents for this work, design, data analysis, manuscript writing, fund raising, and final approval of manuscript; M.L.: conception and design, performed experiments, data analysis, manuscript writing, fund-raising, and final approval of manuscript.

ABSTRACT

Cernunnos (also known as XLF) deficiency syndrome is a rare recessive autosomal disorder caused by mutations in the XLF gene, a key factor involved in the end joining step of DNA during nonhomologous end joining (NHEJ) process. Human patients with XLF mutations display microcephaly, developmental and growth delays, and severe immunodeficiency. While the clinical phenotype of DNA damage disorders, including XLF Syndrome, has been described extensively, the underlying mechanisms of disease onset, are as yet, undefined. We have been able to generate an induced pluripotent stem cell (iPSC) model of XLF deficiency, which accurately replicates the double-strand break repair deficiency observed in XLF patients. XLF patient-specific iPSCs (XLF-iPSC) show typical expression of pluripotency markers, but have altered in vitro differentiation capacity and an inability to generate teratomas comprised of all three germ layers in vivo. Our results demonstrate that XLF-iPSCs possess a weak NHEJ-mediated DNA repair capacity that is incapable of coping with the DNA lesions introduced by physiological stress, normal metabolism, and ionizing radiation. XLF-iPSC lines are capable of hematopoietic differentiation; however, the more primitive subsets of hematopoietic progenitors display increased apoptosis in culture and an inability to repair DNA damage. Together, our findings highlight the importance of NHEJ-mediated-DNA repair in the maintenance of a pristine pool of hematopoietic progenitors during human embryonic development. Stem Cells 2013;31:2015-2023

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