Human dendritic cell differentiation in hematopoietic stem cell-transplanted NOG hFLT3L Tg/mFlt3 KO humanized mice

• Published in: Immunology letters 2024-12, Vol.270, p.106943, Article 106943
• Main Authors: Mu, Yunmei, Ohno, Yusuke, Mochizuki, Misa, Kawai, Kenji, Goto, Motohito, Ogura, Tomoyuki, Takahashi, Riichi, Ito, Mamoru, Ito, Ryoji
• Format: Article
• Language: English
• Subjects: Animals; Cell Differentiation; Dendritic cells; Dendritic Cells - immunology; FLT3L; fms-Like Tyrosine Kinase 3 - genetics; fms-Like Tyrosine Kinase 3 - metabolism; Hematopoietic Stem Cell Transplantation - methods; Hematopoietic stem cells; Hematopoietic Stem Cells - metabolism; Humanized mice; Humans; Membrane Proteins - genetics; Membrane Proteins - metabolism; Mice; Mice, Knockout; Mice, Transgenic
• ISSN: 0165-2478; 1879-0542; 1879-0542
• DOI: 10.1016/j.imlet.2024.106943

•Overexpression of hFLT3L suppresses an engraftment of human hematopoietic cells.•NOG-hFLT3L Tg mice develop murine myeloid leukemia in the BM.•NOG-hFLT3 Tg/mFlt3 KO mice inhibit the leukemia and allow human cell engraftment.•Human DC subsets are successfully differentiated in NOG-hFLT3 Tg/mFlt3 KO mice. Human immune system-reconstituted humanized mice are useful animal models to study human immunology in vivo. Human hematopoietic stem cell-transferred NOG mice are well recognized as humanized immune system models with reconstitution of mature lymphoid lineage cells such as T and B cells. However, human myeloid lineage cells including dendritic cells (DCs) do not fully differentiate in conventional NOG mice. DCs play a crucial role in adaptive immunity through antigen presentation to T cells to acquire antigen specificity. In this study, we established a novel humanized mouse with human DC differentiation. To induce DCs, we generated human Fms-like tyrosine kinase 3 ligand (hFLT3L) transgenic NOG (hFLT3L-Tg) mice and transferred human CD34+ hematopoietic stem cells (HSC) into them. Unexpectedly, low frequency of human cell engraftment was observed in the hFLT3L-Tg mice after HPC reconstitution. In the Tg mice, mouse CD11b+Gr1− myeloid cells were markedly expanded in the bone marrow due to the cross-reaction between hFLT3L and mouse Flt3 receptor, and these myeloid leukemia-like cells interfered with the engraftment of human hematopoietic cells in hFLT3L-Tg mice. To avoid this cross-reaction, we further generated NOG FLT3 receptor KO (mFlt3 KO) mice by CRISPR/Cas9 technique, and the KO mice combined with hFLT3L Tg mice to create hFLT3L Tg/mFlt3 KO (FL Tg/KO) mice. Mouse CD11b+Gr1− leukemia-like cells did not proliferate in FL Tg/KO mice due to blockade of the FLT3 signals in mouse leukocytes. After human HSC transplantation, human CD45+ cells were successfully engrafted in FL Tg/KO mice. Furthermore, major subsets of human DC populations, cDC1, cDC2, and pDC, and skin Langerhans cells were significantly differentiated in FL Tg/KO mice. Therefore, these humanized mouse models are potentially valuable in the investigation of DC-mediated human adaptive immune responses in vivo.