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

Yunmei Mu; Yusuke Ohno; Misa Mochizuki; Kenji Kawai; Motohito Goto; Tomoyuki Ogura; Riichi Takahashi; Mamoru Ito; Ryoji Ito

doi:10.1016/j.imlet.2024.106943

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

Immunol Lett. 2024 Nov 12:270:106943. doi: 10.1016/j.imlet.2024.106943. Online ahead of print.

Authors

Yunmei Mu¹, Yusuke Ohno², Misa Mochizuki², Kenji Kawai², Motohito Goto², Tomoyuki Ogura², Riichi Takahashi², Mamoru Ito², Ryoji Ito³

Affiliations

¹ Central Institute for Experimental Medicine and Life Science, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan; Department of Immunology, Mayo Clinic College of Medicine and Science, Rochester, Minnesota, 55901, USA.
² Central Institute for Experimental Medicine and Life Science, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan.
³ Central Institute for Experimental Medicine and Life Science, 3-25-12 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa 210-0821, Japan. Electronic address: rito@ciea.or.jp.

PMID: 39536946
DOI: 10.1016/j.imlet.2024.106943

Abstract

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.

Keywords: Dendritic cells; FLT3L; Hematopoietic stem cells; Humanized mice.