Therapeutically relevant engraftment of a CRISPR-Cas9–edited HSC-enriched population with HbF reactivation in nonhuman primates

O Humbert, S Radtke, C Samuelson… - Science translational …, 2019 - science.org
O Humbert, S Radtke, C Samuelson, RR Carrillo, AM Perez, SS Reddy, C Lux, S Pattabhi
Science translational medicine, 2019science.org
Reactivation of fetal hemoglobin (HbF) is being pursued as a treatment strategy for
hemoglobinopathies. Here, we evaluated the therapeutic potential of hematopoietic stem
and progenitor cells (HSPCs) edited with the CRISPR-Cas9 nuclease platform to
recapitulate naturally occurring mutations identified in individuals who express increased
amounts of HbF, a condition known as hereditary persistence of HbF. CRISPR-Cas9
treatment and transplantation of HSPCs purified on the basis of surface expression of the …
Reactivation of fetal hemoglobin (HbF) is being pursued as a treatment strategy for hemoglobinopathies. Here, we evaluated the therapeutic potential of hematopoietic stem and progenitor cells (HSPCs) edited with the CRISPR-Cas9 nuclease platform to recapitulate naturally occurring mutations identified in individuals who express increased amounts of HbF, a condition known as hereditary persistence of HbF. CRISPR-Cas9 treatment and transplantation of HSPCs purified on the basis of surface expression of the CD34 receptor in a nonhuman primate (NHP) autologous transplantation model resulted in up to 30% engraftment of gene-edited cells for >1 year. Edited cells effectively and stably reactivated HbF, as evidenced by up to 18% HbF-expressing erythrocytes in peripheral blood. Similar results were obtained by editing highly enriched stem cells, defined by the markers CD34+CD90+CD45RA, allowing for a 10-fold reduction in the number of transplanted target cells, thus considerably reducing the need for editing reagents. The frequency of engrafted, gene-edited cells persisting in vivo using this approach may be sufficient to ameliorate the phenotype for a number of genetic diseases.
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