RUNX-1 haploinsufficiency causes a marked deficiency of megakaryocyte-biased hematopoietic progenitor cells

Blood. 2021 May 13;137(19):2662-2675. doi: 10.1182/blood.2020006389.


Patients with familial platelet disorder with a predisposition to myeloid malignancy (FPDMM) harbor germline monoallelic mutations in a key hematopoietic transcription factor, RUNX-1. Previous studies of FPDMM have focused on megakaryocyte (Mk) differentiation and platelet production and signaling. However, the effects of RUNX-1 haploinsufficiency on hematopoietic progenitor cells (HPCs) and subsequent megakaryopoiesis remains incomplete. We studied induced pluripotent stem cell (iPSC)-derived HPCs (iHPCs) and Mks (iMks) from both patient-derived lines and a wild-type (WT) line modified to be RUNX-1 haploinsufficient (RUNX-1+/-), each compared with their isogenic WT control. All RUNX-1+/- lines showed decreased iMk yield and depletion of an Mk-biased iHPC subpopulation. To investigate global and local gene expression changes underlying this iHPC shift, single-cell RNA sequencing was performed on sorted FPDMM and control iHPCs. We defined several cell subpopulations in the Mk-biased iHPCs. Analyses of gene sets upregulated in FPDMM iHPCs indicated enrichment for response to stress, regulation of signal transduction, and immune signaling-related gene sets. Immunoblot analyses in FPDMM iMks were consistent with these findings, but also identified augmented baseline c-Jun N-terminal kinase (JNK) phosphorylation, known to be activated by transforming growth factor-β1 (TGF-β1) and cellular stressors. These findings were confirmed in adult human CD34+-derived stem and progenitor cells (HSPCs) transduced with lentiviral RUNX1 short hairpin RNA to mimic RUNX-1+/-. In both iHPCs and CD34+-derived HSPCs, targeted inhibitors of JNK and TGF-β1 pathways corrected the megakaryopoietic defect. We propose that such intervention may correct the thrombocytopenia in patients with FPDMM.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Base Sequence
  • Core Binding Factor Alpha 2 Subunit / deficiency*
  • Core Binding Factor Alpha 2 Subunit / genetics
  • Flow Cytometry
  • Haploinsufficiency
  • Hematopoietic Stem Cells / pathology*
  • Humans
  • Immunophenotyping
  • Induced Pluripotent Stem Cells / cytology
  • MAP Kinase Signaling System
  • Megakaryocytes / pathology*
  • Neoplastic Syndromes, Hereditary / genetics
  • Neoplastic Syndromes, Hereditary / pathology*
  • Platelet Glycoprotein GPIb-IX Complex / analysis
  • RNA, Small Interfering / genetics
  • Recombinant Proteins / metabolism
  • Signal Transduction
  • Single-Cell Analysis
  • Thrombopoiesis
  • Transforming Growth Factor beta1 / physiology


  • Core Binding Factor Alpha 2 Subunit
  • Platelet Glycoprotein GPIb-IX Complex
  • RNA, Small Interfering
  • RUNX1 protein, human
  • Recombinant Proteins
  • Transforming Growth Factor beta1