title: Long-Term Engraftment and Fetal Globin Induction uponBCL11AGene Editing in Bone-Marrow-Derived CD34+Hematopoietic Stem and Progenitor Cells.
abstract: To develop an effective and sustainable cell therapy for sickle cell disease (SCD), we investigated the feasibility of targeted disruption of theBCL11Agene, either within exon 2 or at the GATAA motif in the intronic erythroid-specific enhancer, using zinc finger nucleases in human bone marrow (BM) CD34+hematopoietic stem and progenitor cells (HSPCs). Both targeting strategies upregulated fetal globin expression in erythroid cells to levels predicted to inhibit hemoglobin S polymerization. However, complete inactivation ofBCL11Aresulting from bi-allelic frameshift mutations inBCL11Aexon 2 adversely affected erythroid enucleation. In contrast, bi-allelic disruption of the GATAA motif in the erythroid enhancer ofBCL11Adid not negatively impact enucleation. Furthermore,BCL11Aexon 2-edited BM-CD34+cells demonstrated a significantly reduced engraftment potential in immunodeficient mice. Such an adverse effect on HSPC function was not observed uponBCL11Aerythroid-enhancer GATAA motif editing, because enhancer-edited CD34+cells achieved robust long-term engraftment and gave rise to erythroid cells with elevated levels of fetal globin expression when chimeric BM was cultured ex vivo. Altogether, our results support further clinical development of theBCL11Aerythroid-specific enhancer editing in BM-CD34+HSPCs as an autologous stem cell therapy in SCD patients.
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Kai-Hsin
authors.initials: KH
authors.lastname: Chang
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Smith
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Timothy
authors.initials: T
authors.lastname: Sullivan
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Qianhe
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Jason A
authors.initials: JA
authors.lastname: West
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Mei
authors.initials: M
authors.lastname: Liu
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Benjamin F
authors.initials: BF
authors.lastname: Vieira
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Chao
authors.initials: C
authors.lastname: Sun
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Vu P
authors.initials: VP
authors.lastname: Hong
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Mingxuan
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Xiao
authors.initials: X
authors.lastname: Yang
authors.affiliation: Sangamo BioSciences, Richmond, CA 94804, USA.
authors.forename: Andreas
authors.initials: A
authors.lastname: Reik
authors.affiliation: Sangamo BioSciences, Richmond, CA 94804, USA.
authors.forename: Fyodor D
authors.initials: FD
authors.lastname: Urnov
authors.affiliation: Sangamo BioSciences, Richmond, CA 94804, USA.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Rebar
authors.affiliation: Sangamo BioSciences, Richmond, CA 94804, USA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Holmes
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Olivier
authors.initials: O
authors.lastname: Danos
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Biogen, Cambridge, MA 02142, USA.
authors.forename: Siyuan
authors.initials: S
authors.lastname: Tan
keywords: BCL11A; fetal globin reactivation; fetal hemoglobin; gene therapy; genome editing; hemoglobinopathies; zinc finger nucleases