Differential DNA methylation occurs in RUNX1 heterozygous mutations harboring hematopoietic progenitor cells [FLI1_EM]

Background: Familial platelet disorder (FPD) is an autosomal dominant disease caused by a heterozygous germline mutation inRUNX1. FPD patients show not only thrombocytopenia with platelet dysfunction, but also a high level of developing hematological malignancies, strongly suggesting that FPD is in a precancerous state. However, the DNA methylation status of FPD has not yet been elucidated due to no animal models for FPD and the difficulty in obtaining FPD patient-derived samples. Results: We found that differentiation efficiencies into HPCs and megakaryocytes was reduced in the FPD-mimicking cells, which were established by genome editing for human iPS cells as a FPD-model, compared with those of wild-type cells. The FPD-mimicking HPCs were subjected to DNA methylation analysis, and the HPCs showed the distinct DNA methylation patterns compared to wild-type HPCs. Furthermore, we demonstrated a putative causative transcription factor of the differential DNA hypermethylation, which are involved in both promoting the binding site-directed DNA demethylation and regulating megakaryopoiesis. Overall design: We performed the methylome analysis of iPS cells overexpressed FLI1, a putative causative transcription factor for differential DNA hypermethylation in FPD-mimicking HPCs, by doxycycline (DOX)-inducible manner to validate whether FLI1 induces the DNA demethylation at its binding sites in vitro.