Naturally occurring, large deletions in the beta-globin locus result in hereditary persistence of fetal hemoglobin, a condition that mitigates the clinical severity of sickle cell disease (SCD) and beta-thalassemia. We designed a clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) (CRISPR/Cas9) strategy to disrupt a 13.6-kb genomic region encompassing the delta- and beta-globin genes and a putative gamma-delta intergenic fetal hemoglobin (HbF) silencer. Disruption of just the putative HbF silencer results in a mild increase in gamma-globin expression, whereas deletion or inversion of a 13.6-kb region causes a robust reactivation of HbF synthesis in adult erythroblasts that is associated with epigenetic modifications and changes in chromatin contacts within the beta-globin locus. In primary SCD patient-derived hematopoietic stem/progenitor cells, targeting the 13.6-kb region results in a high proportion of gamma-globin expression in erythroblasts, increased HbF synthesis, and amelioration of the sickling cell phenotype. Overall, this study provides clues for a potential CRISPR/Cas9 genome editing approach to the therapy of beta-hemoglobinopathies.
Induction of fetal hemoglobin synthesis by CRISPR/Cas9-mediated editing of the human β-globin locus / Antoniani, Chiara; Meneghini, Vasco; Lattanzi, Annalisa; Felix, Tristan; Romano, Oriana; Magrin, Elisa; Weber, Leslie; Pavani, Giulia; El Hoss, Sara; Kurita, Ryo; Nakamura, Yukio; Cradick, Thomas J; Lundberg, Ante S; Porteus, Matthew; Amendola, Mario; El Nemer, Wassim; Cavazzana, Marina; Mavilio, Fulvio; Miccio, Annarita. - In: BLOOD. - ISSN 0006-4971. - 131:17(2018), pp. 1960-1973. [10.1182/blood-2017-10-811505]