Functional cooperation between CCAAT/enhancer-binding proteins and the vitamin D receptor in regulation of 25-hydroxyvitamin D3 24-hydroxylase

Puneet Dhawan, Xiaorong Peng, Amelia L.M. Sutton, Paul N. MacDonald, Colleen M. Croniger, Christian Trautwein, Michael Centrella, Thomas L. McCarthy, Sylvia Christakos

Research output: Contribution to journalArticlepeer-review

86 Scopus citations

Abstract

1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] induces the synthesis of 25-hydroxyvitamin D3 24-hydroxylase [24(OH)ase], an enzyme involved in its catabolism, thereby regulating its own metabolism. Here we demonstrate that CCAAT enhancer binding protein β (C/EBPβ) is induced by 1,25(OH)2D3 in kidney and in osteoblastic cells and is a potent enhancer of vitamin D receptor (VDR)-mediated 24(OH)ase transcription. Transfection studies indicate that 1,25(OH) 2D3 induction of 24(OH)ase transcription is enhanced a maximum of 10-fold by C/EBPβ. Suppression of 1,25(OH)2D 3-induced 24(OH)ase transcription was observed with dominant negative C/EBP or osteoblastic cells from C/EBPβ-/- mice. A C/EBP site was identified at positions -395 to -388 (-395/-388) in the rat 24(OH)ase promoter. Mutation of this site inhibited C/EBPβ binding and markedly attenuated the transcriptional response to C/EBPβ. We also report the cooperation of CBP/p300 with C/EBPβ in regulating VDR-mediated 24(OH)ase transcription. We found that not only 1,25(OH)2D3 but also parathyroid hormone (PTH) can induce C/EBPβ expression in osteoblaslic cells. PTH potentiated the induction of C/EBPβ and 24(OH)ase expression in response to 1,25(OH)2D3 in osteoblastic cells. Data with the human VDR promoter (which contains two putative C/EBP sites) indicate a role for C/EBPβ in the protein kinase A-mediated induction of VDR transcription. From this study a fundamental role has been established for the first time for cooperative effects and cross talk between the C/EBP family of transcription factors and VDR in 1,25(OH)2D3-induced transcription. These findings also indicate a novel role for C/EBPβ in the cross talk between PTH and 1,25(OH)2D3 that involves the regulation of VDR transcription.

Original languageEnglish (US)
Pages (from-to)472-487
Number of pages16
JournalMolecular and cellular biology
Volume25
Issue number1
DOIs
StatePublished - Jan 2005

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology

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