RUNX1-Induced DNA Demethylation Drives Hematopoietic Stem and Progenitor Cell Development

This study investigates the role of RUNX1’s DNA demethylation function in hematopoietic differentiation, revealing its necessity for generating hematopoietic stem and progenitor cells (HSPCs). Using CRISPR-edited iPSC lines—TADΔ (truncated transactivation domain) and Runt-VP64 (TAD replaced with VP64)—we demonstrated that RUNX1’s ability to induce DNA demethylation is critical for HSPC emergence. While wild-type RUNX1 enabled robust HSPC production (41.1% efficiency), Runt-VP64 and TADΔ severely impaired differentiation (13.5% and 0.024% efficiency, respectively). Methylome analysis linked RUNX1-binding motifs to differentially methylated regions (DMRs) in wild-type cells, absent in mutants, highlighting RUNX1’s role in site-specific demethylation during progenitor cell emergence. These findings establish RUNX1’s DNA demethylation activity as essential for initiating hematopoietic lineage commitment, providing novel insights into epigenetic regulation of hematopoiesis.