Peripheral PDGFRα+gp38+ mesenchymal cells support the differentiation of fetal liver–derived ILC2

• DOI: 10.1084/jem.20172310
• Publication Date: 2018-05-04T17:10:18Z
• Authors: Satoshi Koga; Katsuto Hozumi; Ken-ichi Hirano; Masaki Yazawa; Tommy Terooatea; Aki Minoda; Takashi Nagasawa; Shigeo Koyasu; Kazuyo Moro
• Keywords: 0301 basic medicine; B-Lymphocytes; Membrane Glycoproteins; Receptor, Platelet-Derived Growth Factor alpha; Receptors, Notch; Interleukin-7; Intracellular Signaling Peptides and Proteins; Membrane Proteins; Cell Differentiation; Mesenchymal Stem Cells; GATA3 Transcription Factor; Lymphoid Progenitor Cells; Immunity, Innate; Mice, Inbred C57BL; 03 medical and health sciences; Fetus; Liver; Animals; Cell Lineage; Mesentery; Lymphocytes; Research Articles; Signal Transduction

Group 2 innate lymphoid cells (ILC2s) are derived from common lymphoid progenitors (CLPs) via several specific precursors, and the transcription factors essential for ILC2 differentiation have been extensively studied. However, the external factors regulating commitment to the ILC lineage as well as the sites and stromal cells that constitute the optimal microenvironment for ILC2-specific differentiation are not fully defined. In this study, we demonstrate that three key external factors, the concentration of interleukin 7 (IL-7) and strength and duration of Notch signaling, coordinately determine the fate of CLP toward the T, B, or ILC lineage. Additionally, we identified three stages of ILC2 in the fetal mesentery that require STAT5 signals for maturation: ILC progenitors, CCR9+ ILC2 progenitors, and KLRG1− immature ILC2. We further demonstrate that ILC2 development is supported by mesenteric platelet-derived growth factor receptor α (PDGFRα)+ glycoprotein 38 (gp38)+ mesenchymal cells. Collectively, our results suggest that early differentiation of ILC2 occurs in the fetal liver via IL-7 and Notch signaling, whereas final differentiation occurs in the periphery with the aid of PDGFRα+gp38+ cells.