Marion William, Boettcher Steffen, Ruiz-Torres Sonya, Lummertz da Rocha Edroaldo, Lundin Vanessa, Morris Vivian, Chou Stephanie, Zhao Anna M, Kubaczka Caroline, Aumais Olivia, Zhang Yosra, Shimamura Akiko, Schlaeger Thorsten M, North Trista E, Ebert Benjamin L, Wells Susanne I, Daley George Q, Rowe R Grant
Stem Cell Program, Boston Children's Hospital, Boston, MA.
Division of Hematology, Brigham and Women's Hospital, Boston, MA.
Blood Adv. 2020 Oct 13;4(19):4679-4692. doi: 10.1182/bloodadvances.2020001593.
Fanconi anemia (FA) is a disorder of DNA repair that manifests as bone marrow (BM) failure. The lack of accurate murine models of FA has refocused efforts toward differentiation of patient-derived induced pluripotent stem cells (IPSCs) to hematopoietic progenitor cells (HPCs). However, an intact FA DNA repair pathway is required for efficient IPSC derivation, hindering these efforts. To overcome this barrier, we used inducible complementation of FANCA-deficient IPSCs, which permitted robust maintenance of IPSCs. Modulation of FANCA during directed differentiation to HPCs enabled the production of FANCA-deficient human HPCs that recapitulated FA genotoxicity and hematopoietic phenotypes relative to isogenic FANCA-expressing HPCs. FANCA-deficient human HPCs underwent accelerated terminal differentiation driven by activation of p53/p21. We identified growth arrest specific 6 (GAS6) as a novel target of activated p53 in FANCA-deficient HPCs and modulate GAS6 signaling to rescue hematopoiesis in FANCA-deficient cells. This study validates our strategy to derive a sustainable, highly faithful human model of FA, uncovers a mechanism of HPC exhaustion in FA, and advances toward future cell therapy in FA.
范可尼贫血（FA）是一种DNA修复障碍疾病，表现为骨髓（BM）衰竭。由于缺乏准确的FA小鼠模型，研究重点已重新转向将患者来源的诱导多能干细胞（IPSC）分化为造血祖细胞（HPC）。然而，高效的IPSC衍生需要完整的FA DNA修复途径，这阻碍了这些努力。为了克服这一障碍，我们使用了FANCA缺陷型IPSC的诱导互补技术，从而能够强力维持IPSC。在定向分化为HPC的过程中对FANCA进行调控，使得能够产生FANCA缺陷型人类HPC，相对于表达同基因FANCA的HPC，其重现了FA基因毒性和造血表型。FANCA缺陷型人类HPC在p53/p21激活的驱动下经历加速的终末分化。我们将生长停滞特异性蛋白6（GAS6）鉴定为FANCA缺陷型HPC中活化p53的一个新靶点，并调节GAS6信号传导以挽救FANCA缺陷型细胞中的造血功能。本研究验证了我们构建可持续、高度忠实的人类FA模型的策略，揭示了FA中HPC耗竭的机制，并朝着FA未来的细胞治疗迈进。
