title: A genome-editing strategy to treat β-hemoglobinopathies that recapitulates a mutation associated with a benign genetic condition.
abstract: Disorders resulting from mutations in the hemoglobin subunit beta gene (HBB; which encodes β-globin), mainly sickle cell disease (SCD) and β-thalassemia, become symptomatic postnatally as fetal γ-globin expression from two paralogous genes, hemoglobin subunit gamma 1 (HBG1) and HBG2, decreases and adult β-globin expression increases, thereby shifting red blood cell (RBC) hemoglobin from the fetal (referred to as HbF or α2γ2) to adult (referred to as HbA or α2β2) form. These disorders are alleviated when postnatal expression of fetal γ-globin is maintained. For example, in hereditary persistence of fetal hemoglobin (HPFH), a benign genetic condition, mutations attenuate γ-globin-to-β-globin switching, causing high-level HbF expression throughout life. Co-inheritance of HPFH with β-thalassemia- or SCD-associated gene mutations alleviates their clinical manifestations. Here we performed CRISPR-Cas9-mediated genome editing of human blood progenitors to mutate a 13-nt sequence that is present in the promoters of the HBG1 and HBG2 genes, thereby recapitulating a naturally occurring HPFH-associated mutation. Edited progenitors produced RBCs with increased HbF levels that were sufficient to inhibit the pathological hypoxia-induced RBC morphology found in SCD. Our findings identify a potential DNA target for genome-editing-mediated therapy of β-hemoglobinopathies.
authors.affiliation: Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.|Medical Scientist Training Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Traxler
authors.affiliation: Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
authors.forename: Yu
authors.initials: Y
authors.lastname: Yao
authors.affiliation: Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
authors.forename: Yong-Dong
authors.identifier: 0000-0001-8751-9216
authors.initials: YD
authors.lastname: Wang
authors.affiliation: Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
authors.forename: Kaitly J
authors.initials: KJ
authors.lastname: Woodard
authors.affiliation: Cell Engineering Division, RIKEN BioResource Center, Tsukuba, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Kurita
authors.affiliation: Cell Engineering Division, RIKEN BioResource Center, Tsukuba, Japan.|Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Medical Research Council, Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, Oxford University, Oxford, UK.
authors.forename: Jim R
authors.initials: JR
authors.lastname: Hughes
authors.affiliation: Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA.
authors.forename: Ross C
authors.identifier: 0000-0003-4084-7516
authors.initials: RC
authors.lastname: Hardison
authors.affiliation: Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
authors.forename: Gerd A
authors.initials: GA
authors.lastname: Blobel
authors.affiliation: Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
authors.forename: Chunliang
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Hematology, St. Jude Children's Research Hospital, Memphis, Tennessee, USA.
authors.forename: Mitchell J
authors.identifier: 0000-0002-6734-4858
authors.initials: MJ
authors.lastname: Weiss
mesh_terms: D000755:Anemia, Sickle Cell / Q000235:genetics / Q000628:therapy*; D064113:CRISPR-Cas Systems; D015672:Erythroid Precursor Cells; D005319:Fetal Hemoglobin / Q000235:genetics* / Q000378:metabolism; D000072669:Gene Editing / Q000379:methods*; D006441:Hemoglobin A / Q000235:genetics / Q000378:metabolism; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D016297:Mutagenesis, Site-Directed / Q000379:methods*; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055544:beta-Globins / Q000235:genetics*; D017086:beta-Thalassemia / Q000235:genetics / Q000628:therapy*; D055545:gamma-Globins / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; D055544:beta-Globins; D055545:gamma-Globins; D006441:Hemoglobin A; D005319:Fetal Hemoglobin