Gene-Correction Rescues Reprogramming of Fanconi Anemia Fibroblasts and Enables Hematopoietic Differentiation of FA Induced Pluripotent Stem Cells in Vitro and In Vivo

Autor: In-Hyun Park, Elke Grassman, Thorsten M. Schlaeger, Axel Schambach, Kristina Brumme, Chad E. Harris, Kalindi Parmar, George Q. Daley, David A. Williams, Rutesh Vyas, Lars Mueller, Michael D. Milsom, Alan D. D'Andrea, London Wendy, Kelly Strait, Alex Devine
Rok vydání: 2011
Předmět:
Zdroj: Blood. 118:672-672
ISSN: 1528-0020
0006-4971
DOI: 10.1182/blood.v118.21.672.672
Popis: Abstract 672 Fanconi anemia (FA) is a recessive syndrome characterized by progressive fatal bone marrow failure and chromosomal instability. FA cells have inactivating mutations in a signaling pathway that is critical for maintaining genomic integrity and repairing DNA damage caused by cross-linking agents. Transgenic expression of the implicated genes corrects the phenotype of hematopoietic cells but previous attempts at gene therapy failed largely due to inadequate numbers of hematopoietic stem cells available for gene correction and autologous engraftment. Induced pluripotent stem cells (iPSC) constitute an alternate source of autologous cells, which are amenable to ex vivo expansion and genetic correction. While fibroblasts from a limited number of FA patients have been reported to fail to undergo reprogramming (Raya et al., Nature, 2009), reproducible observations and mechanistic studies ascertained in an extended panel of patient cells and murine knock-out models are lacking to date. We undertook direct reprogramming of ten unique human FA primary fibroblast samples of the FA-A, FA-C, FA-G, and FA-D2 complementation groups. Using standard four-factor reprogramming, no human FA iPSC colonies were obtained in cells defective in the FA pathway. By contrast, reprogramming of gene-corrected patient samples, augmented by hypoxia (5%O2), yielded multiple pluripotent iPSC lines, confirming a critical cell-intrinsic role of the FA pathway in reprogramming. To determine if gene-corrected FA iPSC could be therapeutically useful, we performed karyotype analyses and evaluated in vitro hematopoietic differentiation in three FA-A iPSC lines. These FA patient iPSC lines were karyotypically normal and showed a robust multilineage hematopoietic differentiation potential, resulting in erythroid and myeloid hematopoietic colony forming units to a similar degree as compared to normal donor iPSC controls. We hypothesized that the reprogramming resistance of FA cells is due to defective DNA repair and genomic instability. To explore the mechanisms of the reprogramming defect, we transduced wild type (wt) tail-tip fibroblasts (TTF) with the reprogramming vectors. We observed significantly increased FANCD2 foci formation during reprogramming (median percentage of FANCD2 foci: mock-transduced TTF 2.5%, reprogrammed TTF 20.5%, n=8, p Disclosures: Daley: iPierian, Inc: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Epizyme, Inc: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Verastem, Inc: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Solasia, KK: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; MPM Capital, Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: Membership on an entity's Board of Directors or advisory committees.
Databáze: OpenAIRE
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