Therapeutic base editing of human hematopoietic stem cells

Nat Med. 2020 Apr;26(4):535-541. doi: 10.1038/s41591-020-0790-y. Epub 2020 Mar 16.


Base editing by nucleotide deaminases linked to programmable DNA-binding proteins represents a promising approach to permanently remedy blood disorders, although its application in engrafting hematopoietic stem cells (HSCs) remains unexplored. In this study, we purified A3A (N57Q)-BE3 base editor for ribonucleoprotein (RNP) electroporation of human-peripheral-blood-mobilized CD34+ hematopoietic stem and progenitor cells (HSPCs). We observed frequent on-target cytosine base edits at the BCL11A erythroid enhancer at +58 with few indels. Fetal hemoglobin (HbF) induction in erythroid progeny after base editing or nuclease editing was similar. A single therapeutic base edit of the BCL11A enhancer prevented sickling and ameliorated globin chain imbalance in erythroid progeny from sickle cell disease and β-thalassemia patient-derived HSPCs, respectively. Moreover, efficient multiplex editing could be achieved with combined disruption of the BCL11A erythroid enhancer and correction of the HBB -28A>G promoter mutation. Finally, base edits could be produced in multilineage-repopulating self-renewing human HSCs with high frequency as assayed in primary and secondary recipient animals resulting in potent HbF induction in vivo. Together, these results demonstrate the potential of RNP base editing of human HSPCs as a feasible alternative to nuclease editing for HSC-targeted therapeutic genome modification.

Publication types

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

MeSH terms

  • Anemia, Sickle Cell / pathology*
  • Anemia, Sickle Cell / therapy
  • Animals
  • Antigens, CD34 / metabolism
  • CRISPR-Cas Systems
  • Cells, Cultured
  • Feasibility Studies
  • Female
  • Gene Editing* / methods
  • Gene Targeting / methods
  • Genetic Therapy / methods*
  • Hematopoietic Stem Cell Transplantation / methods
  • Hematopoietic Stem Cells / metabolism*
  • Hematopoietic Stem Cells / pathology
  • Heterografts
  • Humans
  • Mice
  • Mice, Inbred NOD
  • Mice, Transgenic
  • Primary Cell Culture
  • Repressor Proteins / genetics*
  • Repressor Proteins / metabolism
  • beta-Thalassemia / pathology
  • beta-Thalassemia / therapy
  • gamma-Globins / genetics*
  • gamma-Globins / metabolism


  • Antigens, CD34
  • BCL11A protein, human
  • Repressor Proteins
  • gamma-Globins