NR4A3 plays a pivotal role in the differentiation of monocyte-derived dendritic cells. Mus musculus

The molecular requirements that guide the differentiation of monocytes into macrophages or monocyte-derived dendritic cells (Mo-DCs) are poorly understood. Here, we demonstrate that the nuclear orphan receptor NR4A3 guides monocyte fate and is essential for Mo-DC differentiation. Nr4a3-/- mice are impaired in the in vivo generation of DC-SIGN+ Mo-DCs following LPS stimulation and, as such, are defective at priming a CD8+ T cell response to gram negative bacteria. We also demonstrate that NR4A3 is an essential downstream effector of IRF4 during in vitro differentiation of Mo-DCs with GM-CSF and IL-4 and that, in absence of NR4A3, monocytes are diverted to macrophages. Our transcriptomic analysis of the genes regulated by NR4A3 reveals that the acquisition of the Mo-DC differentiation program is intertwined with the acquisition of a migratory signature. Furthermore, NR4A3 is critical for steady-state migration of non-lymphoid tissue conventional DCs to lymph nodes. Altogether, our results highlight a unique role for NR4A3 in Mo-DC differentiation and in the acquisition of migratory properties. Overall design: Total RNA from sorted murine monocytes (see above) and from murine monocytes cultured with GM-CSF and IL-4 for 1 and 2 days (2 samples per group from 2 independent experiments) was isolated and sequenced with Illumina HiSeq2000.