Retinoic Acid-Induced CCR9 Expression Requires Transient TCR Stimulation and Cooperativity between NFATc2 and the Retinoic Acid Receptor/Retinoid X Receptor Complex

Abstract

Retinoic acid (RA) imprints gut-homing specificity on T cells upon activation by inducing the expression of chemokine receptor CCR9 and integrin α4β7. CCR9 expression seemed to be more highly dependent on RA than was the α4β7 expression, but its molecular mechanism remained unclear. In this article, we show that NFAT isoforms NFATc1 and NFATc2 directly interact with RA receptor (RAR) and retinoid X receptor (RXR) but play differential roles in RA-induced CCR9 expression on murine naive CD4+ T cells. TCR stimulation for 6–24 h was required for the acquisition of responsiveness to RA and induced activation of NFATc1 and NFATc2. However, RA failed to induce CCR9 expression as long as TCR stimulation continued. After terminating TCR stimulation or adding cyclosporin A to the culture, Ccr9 gene transcription was induced, accompanied by inactivation of NFATc1 and sustained activation of NFATc2. Reporter and DNA-affinity precipitation assays demonstrated that the binding of NFATc2 to two NFAT-binding sites and that of the RAR/RXR complex to an RA response element half-site in the 5′-flanking region of the mouse Ccr9 gene were critical for RA-induced promoter activity. NFATc2 directly bound to RARα and RXRα, and it enhanced the binding of RARα to the RA response element half-site. NFATc1 also bound to the NFAT-binding sites and directly to RARα and RXRα, but it inhibited the NFATc2-dependent promoter activity. These results suggest that the cooperativity between NFATc2 and the RAR/RXR complex is essential for CCR9 expression on T cells and that NFATc1 interferes with the action of NFATc2.

Retinoic acid prevents mesenteric lymph node dendritic cells from inducing IL-13-producing inflammatory Th2 cells

“…For induction of Ccr9 expression in T cells, DCs were pretreated with 1 mM OVA peptide P323-339 for 2 h, washed, and then cocultured with naive CD4 þ T cells. 54 Naive CD4 þ T cells (1 Â 10 5 ) from BALB/c or C57BL/6 mice were cultured for 3 days in the plates coated with anti-CD3 mAb (3 mg ml À 1 ) and anti-CD28 mAb (3 mg ml À 1 ) with or without anti-OX40 or Rat IgG1 isotype control (10 mg ml À 1 ). The culture was diluted with twice its volume of fresh medium, transferred into new wells, and cultured for 3 days.…”

Retinoic Acid and GM-CSF Coordinately Induce Retinal Dehydrogenase 2 (RALDH2) Expression through Cooperation between the RAR/RXR Complex and Sp1 in Dendritic Cells

“…pSG5-RARα was a kind gift from Dr. P. Chambon (IGBMC, Université Louis Pasteur) [22]. pSG5-RXRα was previously described [23].…”

Leukocyte Homing, Fate, and Function Are Controlled by Retinoic Acid

“…NFATc2 enhanced but NFATc1 inhibited RAR-RXR binding to RARE in CCR9 promoter region (148). Only transient T-cell activation allows for CCR9 upregulation as prolonged TCR signaling retains inhibitory NFATc1 in the nucleus.…”

“…The cross-talk between RAR␣ and nuclear factor of activated T cells, cytoplasmic, calcineurin-dependent 1 (NFATc1)/NFATc2 proved essential for CCR9 induction in response to transient TCR stimulation (148). In addition to the direct impact of RA on various genes transcription, RA was found to control microRNAs in different T-cell subsets, which enables RA to function through posttranscriptional regulation of multiple genes (86,187).…”

“…By measuring CCR9 mRNA level in activated CD4 ϩ T cells in the presence of RA, and assessing the binding between NFAT and RAR-RXR complex in CCR9 promoter regions, Ohoka et al (148) demonstrated that transient TCR-mediated signaling and CD28 costimulatory signals induced transcription factor NFATc1 and NFATc2 nuclear translocation. NFATc2 enhanced but NFATc1 inhibited RAR-RXR binding to RARE in CCR9 promoter region (148).…”