Novel lentiviral vectors for gene therapy of sickle cell disease combining gene addition and gene silencing strategies

• Published in: Molecular therapy. Nucleic acids Vol. 32; no. 13; pp. 229 - 246
• Main Authors: Brusson, Mégane, Chalumeau, Anne, Martinucci, Pierre, Romano, Oriana, Felix, Tristan, Poletti, Valentina, Scaramuzza, Samantha, Ramadier, Sophie, Masson, Cecile, Ferrari, Giuliana, Mavilio, Fulvio, Cavazzana, Marina, Amendola, Mario, Miccio, Annarita
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 13.06.2023; Elsevier; American Society of Gene & Cell Therapy
• Subjects: gene addition; gene silencing; gene therapy; Human health and pathology; lentiviral vectors; Life Sciences; microRNA; MT: Non-coding RNAs; Original; sickle cell disease; βs silencing; βs silencing; lentiviral vectors; gene silencing; gene therapy; microRNA; gene addition; MT: Non-coding RNAs; sickle cell disease
• ISSN: 2162-2531; 2162-2531
• DOI: 10.1016/j.omtn.2023.03.012

Sickle cell disease (SCD) is due to a mutation in the β-globin gene causing production of the toxic sickle hemoglobin (HbS; α2βS2). Transplantation of autologous hematopoietic stem and progenitor cells (HSPCs) transduced with lentiviral vectors (LVs) expressing an anti-sickling β-globin (βAS) is a promising treatment; however, it is only partially effective, and patients still present elevated HbS levels. Here, we developed a bifunctional LV expressing βAS3-globin and an artificial microRNA (amiRNA) specifically downregulating βS-globin expression with the aim of reducing HbS levels and favoring βAS3 incorporation into Hb tetramers. Efficient transduction of SCD HSPCs by the bifunctional LV led to a substantial decrease of βS-globin transcripts in HSPC-derived erythroid cells, a significant reduction of HbS+ red cells, and effective correction of the sickling phenotype, outperforming βAS gene addition and BCL11A gene silencing strategies. The bifunctional LV showed a standard integration profile, and neither HSPC viability, engraftment, and multilineage differentiation nor the erythroid transcriptome and miRNAome were affected by the treatment, confirming the safety of this therapeutic strategy. In conclusion, the combination of gene addition and gene silencing strategies can improve the efficacy of current LV-based therapeutic approaches without increasing the mutagenic vector load, thus representing a novel treatment for SCD. [Display omitted] Sickle cell disease is due to a mutation in the β-globin gene causing production of the toxic sickle hemoglobin. Brusson et al. developed a lentiviral vector expressing an anti-sickling β-globin and an artificial microRNA downregulating βS-globin expression; this vector reduces HbS levels and effectively corrects the sickling phenotype.