Use of HSC-targeted LNP to generate a mouse model of lethal α-thalassemia and treatment via lentiviral gene therapy

•Deletion of the α-globin genes induces a lethal phenotype associated with high levels of red blood cells in circulation.•Transduction with a lentiviral vector expressing the human α-globin gene prevents mice from developing the lethal phenotype. [Display omitted] α-Thalassemia (AT) is one of the mo...

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Published in:Blood 2024-07
Main Authors: Chappell, Maxwell E., Breda, Laura, Tricoli, Lucas, Guerra, Amaliris, Jarocha, Danuta, Castruccio Castracani, Carlo, Papp, Tyler E., Tanaka, Naoto, Hamilton, Nolan, Triebwasser, Michael P., Ghiaccio, Valentina, Fedorky, Megan T., Gollomp, Kandace L., Bochenek, Veronica, Roche, Aoife M., Everett, John K., Cook, Emma J., Bushman, Frederic D., Teawtrakul, Nattiya, Glentis, Stavros, Kattamis, Antonis, Mui, Barbara L., Tam, Ying K., Weissman, Drew, Abdulmalik, Osheiza, Parhiz, Hamideh, Rivella, Stefano
Format: Article
Language:English
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Summary:•Deletion of the α-globin genes induces a lethal phenotype associated with high levels of red blood cells in circulation.•Transduction with a lentiviral vector expressing the human α-globin gene prevents mice from developing the lethal phenotype. [Display omitted] α-Thalassemia (AT) is one of the most commonly occurring inherited hematological diseases. However, few treatments are available, and allogeneic bone marrow transplantation is the only available therapeutic option for patients with severe AT. Research into AT has remained limited because of a lack of adult mouse models, with severe AT typically resulting in in utero lethality. By using a lipid nanoparticle (LNP) targeting the receptor CD117 and delivering a Cre messenger RNA (mRNACreLNPCD117), we were able to delete floxed α-globin genes at high efficiency in hematopoietic stem cells (HSC) ex vivo. These cells were then engrafted in the absence or presence of a novel α-globin–expressing lentiviral vector (ALS20αI). Myeloablated mice infused with mRNACreLNPCD117–treated HSC showed a complete knock out (KO) of α-globin genes. They showed a phenotype characterized by the synthesis of hemoglobin H (HbH; also known as β-tetramers or β4), aberrant erythropoiesis, and abnormal organ morphology, culminating in lethality ∼8 weeks after engraftment. Mice infused with mRNACreLNPCD117–treated HSC with at least 1 copy of ALS20αI survived long term with normalization of erythropoiesis, decreased production of HbH, and amelioration of the abnormal organ morphology. Furthermore, we tested ALS20αI in erythroid progenitors derived from α-globin–KO CD34+ cells and cells isolated from patients with both deletional and nondeletional HbH disease, demonstrating improvement in α-globin/β-globin mRNA ratio and reduction in the formation of HbH by high-performance liquid chromatography. Our results demonstrate the broad applicability of LNP for disease modeling, characterization of a novel mouse model of severe AT, and the efficacy of ALS20αI for treating AT.
ISSN:0006-4971
1528-0020
1528-0020
DOI:10.1182/blood.2023023349