Editing a γ-globin repressor binding site restores fetal hemoglobin synthesis and corrects the sickle cell disease phenotype

Leslie Weber , Giacomo Frati , Tristan Felix , Giulia Hardouin , Antonio Casini , Clara Wollenschlaeger , Vasco Meneghini , Cecile Masson , Anne de Cian , Anne Chalumeau , Fulvio Mavilio , Mario Amendola , Isabelle Andre-Schmutz , Anna Cereseto , Wassim El Nemer , Jean-Paul Concordet , Carine Giovannangeli (1) , Marina Cavazzana , Annarita Miccio

1 STRING - Structure et Instabilité des Génomes

Sickle cell disease (SCD) is caused by a single amino acid change in the adult hemoglobin (Hb)  chain that causes Hb polymerization and red blood cell (RBC) sickling. The co-inheritance of mutations causing fetal -globin production in adult life hereditary persistence of fetal Hb (HPFH) reduces the clinical severity of SCD. HPFH mutations in the HBG -globin promoters disrupt binding sites for the repressors BCL11A and LRF. We used CRISPR-Cas9 to mimic HPFH mutations in the HBG promoters by generating insertions and deletions, leading to disruption of known and putative repressor binding sites. Editing of the LRF-binding site in patient-derived hematopoietic stem/progenitor cells (HSPCs) resulted in -globin derepression and correction of the sickling phenotype. Xenotransplantation of HSPCs treated with gRNAs targeting the LRF-binding site showed a high editing efficiency in repopulating HSPCs. This study identifies the LRF-binding site as a potent target for genome-editing treatment of SCD.

Domains: Biochemistry, Molecular Biology; Life Sciences [q-bio]

Leslie Weber, Giacomo Frati, Tristan Felix, Giulia Hardouin, Antonio Casini, et al.. Editing a γ-globin repressor binding site restores fetal hemoglobin synthesis and corrects the sickle cell disease phenotype. Science Advances , 2020, 6 (7), pp.eaay9392. ⟨10.1126/sciadv.aay9392⟩. ⟨mnhn-03100446⟩