PDF(Pubmed)
Abstract：
Familial platelet disorder with associated myeloid malignancies (FPDMM) is an autosomal dominant disease caused by heterozygous germline mutations in RUNX1. It is characterized by thrombocytopenia, platelet dysfunction, and a predisposition to hematological malignancies. Although FPDMM is a precursor for diseases involving abnormal DNA methylation, the DNA methylation status in FPDMM remains unknown, largely due to a lack of animal models and challenges in obtaining patient-derived samples. Here, using genome editing techniques, we established two lines of human induced pluripotent stem cells (iPSCs) with different FPDMM-mimicking heterozygous RUNX1 mutations. These iPSCs showed defective differentiation of hematopoietic progenitor cells (HPCs) and megakaryocytes (Mks), consistent with FPDMM. The FPDMM-mimicking HPCs showed DNA methylation patterns distinct from those of wild-type HPCs, with hypermethylated regions showing the enrichment of ETS transcription factor (TF) motifs. We found that the expression of FLI1, an ETS family member, was significantly downregulated in FPDMM-mimicking HPCs with a RUNX1 transactivation domain (TAD) mutation. We demonstrated that FLI1 promoted binding-site-directed DNA demethylation, and that overexpression of FLI1 restored their megakaryocytic differentiation efficiency and hypermethylation status. These findings suggest that FLI1 plays a crucial role in regulating DNA methylation and correcting defective megakaryocytic differentiation in FPDMM-mimicking HPCs with a RUNX1 TAD mutation.
摘要：
家族性血小板疾病伴髓样恶性肿瘤(FPDMM)是一种由RUNX1中的杂合种系突变引起的常染色体显性疾病。它的特点是血小板减少症，血小板功能障碍,和血液恶性肿瘤的易感性。尽管FPDMM是涉及异常DNA甲基化的疾病的前兆，FPDMM中的DNA甲基化状态仍然未知，主要是由于缺乏动物模型和在获得患者来源的样本方面的挑战。这里,使用基因组编辑技术，我们建立了两系具有不同FPDMM模拟杂合RUNX1突变的人诱导多能干细胞(iPSCs).这些iPSCs显示造血祖细胞（HPCs）和巨核细胞（Mks）的分化缺陷，与FPDMM一致。模拟FPDMM的HPCs显示出不同于野生型HPCs的DNA甲基化模式，高甲基化区域显示ETS转录因子（TF）基序的富集。我们发现，ETS家族成员FLI1的表达，在具有RUNX1反式激活域(TAD)突变的FPDMM模拟HPCs中显著下调。我们证明了FLI1促进了结合位点定向的DNA去甲基化，并且FLI1的过表达恢复了它们的巨核细胞分化效率和高甲基化状态。这些发现表明，FLI1在调节DNA甲基化和纠正具有RUNX1TAD突变的FPDMM模拟HPCs的巨核细胞分化缺陷中起着至关重要的作用。
