Choosing the right mouse model: comparison of humanized NSG and NBSGW mice for in vivo HSC gene therapy

• Published in: Blood advances 2024-02, Vol.8 (4), p.916-926
• Main Authors: Choo, Seunga, Wolf, Carl B., Mack, Heather M., Egan, Mitchell J., Kiem, Hans-Peter, Radtke, Stefan
• Format: Article
• Language: English
• Subjects: Animals; Bone Marrow; Genetic Therapy - methods; Hematopoiesis and Stem Cells; Hematopoietic Stem Cells - metabolism; Humans; Lentivirus - genetics; Mice
• ISSN: 2473-9529; 2473-9537; 2473-9537
• DOI: 10.1182/bloodadvances.2023011371

•Thorough characterization of humanized NSG and NBSGW strains including human HSC engraftment, mobilization, and in vivo transduction.•Human HSCs in the murine BM lack sufficient low-density lipoprotein receptor expression and exhibit low VSV-G-LV transduction efficiency. [Display omitted] In vivo hematopoietic stem cell (HSC) gene therapy is an emerging and promising area of focus in the gene therapy field. Humanized mouse models are frequently used to evaluate novel HSC gene therapy approaches. Here, we comprehensively evaluated 2 mouse strains, NSG and NBSGW. We studied human HSC engraftment in the bone marrow (BM), mobilization of BM-engrafted HSCs into circulation, in vivo transduction using vesicular stomatitis virus glycoprotein–pseudotyped lentiviral vectors (VSV-G LVs), and the expression levels of surface receptors needed for transduction of viral vectors. Our findings reveal that the NBSGW strain exhibits superior engraftment of human long-term HSCs compared with the NSG strain. However, neither model resulted in a significant increase in circulating human HSCs after mobilization. We show that time after humanization as well as human chimerism levels and platelet counts in the peripheral blood can be used as surrogates for human HSC engraftment in the BM. Furthermore, we observed low expression of the low-density lipoprotein receptor, a requirement for VSV-G LV transduction, in the human HSCs present in the murine BM. Our comprehensive characterization of humanized mouse models highlights the necessity of proper validation of the model and methods to study in vivo HSC gene therapy strategies.