The orphan nuclear receptor NR4A3 is involved in the function of dendritic cells

Transcriptome analysis of LPS-stimulated bone marrow-derived dendritic cells with NR4A3 gene silencing The NR4A3/NOR1 belongs to the NR4A subfamily of the orphan nuclear hormone receptor superfamily, which is activated in a ligand-independent manner. To examine the role of NR4A3/NOR1 in gene expression of dendritic cells (DCs), we introduced NR4A3 siRNA into bone marrow-derived DCs (BMDCs) and determined the expression levels of mRNA and proteins of cytokines, cell surface molecules, NFκB signaling-related proteins, and transcription factors. The expression level of NR4A3 was markedly up-regulated by TLRs-mediated stimulation in DCs. NR4A3 knockdown significantly suppressed LPS, CpG, or poly I:C-mediated up-regulation of CD80, CD86, IL-10, IL-6, and IL-12. Proliferation and IL-2 production levels of T cells co-cultured with NR4A3-knocked down DCs were significantly lower than that of T cells co-cultured with control DCs. Furthermore, the expression of IKKβ, IRF4, and IRF8 was significantly decreased in NR4A3 siRNA-introduced BMDCs. The knockdown experiments using siRNAs for IKKβ, IRF4, and/or IRF8 indicated that LPS-induced up-regulation of IL-10 and IL-6 was reduced in IKKβ knocked down cells, and that the up-regulation of IL-12 was suppressed by the knockdown of IRF4 and IRF8. Taken together, these results indicate that NR4A3 is involved in TLR-mediated activation and gene expression of DCs. We analyzed gene expression profiles of LPS-stimulated or unstimulated bone marrow-derived dendritic cells with or without NR4A3 gene silencing using the Affymetrix Mouse Gene 1.0 ST platform. Array data was processed and analyzed by GeneSpring software. No techinical replicates were performed.