Retinoic acid and GM-CSF coordinately induce retinal dehydrogenase 2 (RALDH2) expression through cooperation between the RAR/RXR complex and Sp1 in dendritic cells.
Retinoic acid (RA)-producing dendritic cells (DCs) play critical roles in gut immunity. Retinal dehydrogenase 2 (RALDH2) encoded by Aldh1a2 is a key enzyme for generating RA in DCs. Granulocyte-macrophage colony-stimulating factor (GM-CSF) potently induces RALDH2 expression in DCs in an RA-dependent manner, and RA alone weakly induces the expression. However, how GM-CSF and RA induce RALDH2 expression remains unclear. Here, we show that GM-CSF-induced activation of the transcription factor Sp1 and RA-dependent signaling via the RA receptor (RAR)/retinoid X receptor (RXR) complex contribute to Aldh1a2 expression. The RAR antagonist LE540 and the Sp1 inhibitor mithramycin A inhibited GM-CSF-induced Aldh1a2 expression in fms-related tyrosine kinase 3 ligand-generated bone marrow-derived DCs (BM-DCs). ERK and p38 MAPK inhibitors suppressed GM-CSF-induced nuclear translocation of Sp1 and Aldh1a2 expression. Sp1 and the RARα/RXRα complex bound to GC-rich Sp1-binding sites and an RA response element (RARE) half-site, respectively, near the TATA box in the mouse Aldh1a2 promoter. The DNA sequences around these sites were highly conserved among different species. In the presence of RA, ectopic expression of RARα/RXRα and Sp1 synergistically enhanced Aldh1a2 promoter-reporter activity. GM-CSF did not significantly induce Aldh1a2 expression in plasmacytoid DCs, peritoneal macrophages, or T cells, and the Aldh1a2 promoter in these cells was mostly unmethylated. These results suggest that GM-CSF/RA-induced RALDH2 expression in DCs requires cooperative binding of Sp1 and the RAR/RXR complex to the Aldh1a2 promoter, and can be regulated by a DNA methylation-independent mechanism.
Laboratory of Immunology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki-shi, Kagawa, Japan; Japan Science and Technology Agency, CREST, Chiyoda-ku, Tokyo, Japan.
Yoshiharu
Y
Ohoka
Laboratory of Immunology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki-shi, Kagawa, Japan; Japan Science and Technology Agency, CREST, Chiyoda-ku, Tokyo, Japan.
Aya
A
Yokota-Nakatsuma
Laboratory of Immunology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki-shi, Kagawa, Japan; Japan Science and Technology Agency, CREST, Chiyoda-ku, Tokyo, Japan.
Naoko
N
Maeda
Laboratory of Immunology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki-shi, Kagawa, Japan; Japan Science and Technology Agency, CREST, Chiyoda-ku, Tokyo, Japan.
Hajime
H
Takeuchi
Laboratory of Immunology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki-shi, Kagawa, Japan; Japan Science and Technology Agency, CREST, Chiyoda-ku, Tokyo, Japan.
Makoto
M
Iwata
D000445:Aldehyde Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation; D003713:Dendritic Cells / Q000187:drug effects* / Q000378:metabolism; D003984:Dibenzazepines / Q000494:pharmacology; D004357:Drug Synergism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D008926:Plicamycin / Q000031:analogs & derivatives / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D018168:Receptors, Retinoic Acid / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D047488:Retinoid X Receptors / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid; D016329:Sp1 Transcription Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014212:Tretinoin / Q000494:pharmacology*
D003984:Dibenzazepines; C104183:LE 540; D018168:Receptors, Retinoic Acid; D047488:Retinoid X Receptors; D016329:Sp1 Transcription Factor; D014212:Tretinoin; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; C066851:mithramycin A; D000445:Aldehyde Oxidoreductases; C470579:RALDH2 protein, mouse; D008926:Plicamycin