Human haem oxygenase-1 induction by nitro-linoleic acid is mediated by cAMP, AP-1 and E-box response element interactions
| Autor: | Norbert Leitinger, Anupam Agarwal, Bruce A. Freeman, Thomas D. Hock, Junghyun Kim, Marcienne M. Wright |
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| Rok vydání: | 2009 |
| Předmět: |
Response element
E-box CREB Biochemistry Article Cell Line E-Box Elements Small hairpin RNA Mice Transcription (biology) Cyclic AMP Transcriptional regulation Animals Humans Molecular Biology Cells Cultured biology Cell Biology Transfection Nitro Compounds Molecular biology Transcription Factor AP-1 Linoleic Acids Enzyme Induction biology.protein Chromatin immunoprecipitation Heme Oxygenase-1 Protein Binding |
| Zdroj: | Biochemical Journal. 422:353-361 |
| ISSN: | 1470-8728 0264-6021 |
| Popis: | Nitro-fatty acid products of oxidative inflammatory reactions mediate anti-inflammatory cell signalling responses. LNO 2 (nitrolinoleic acid) induces expression of HO-1 (haem oxygenase-1), an enzyme that catabolizes haem into products exhibiting potent anti-inflammatory properties. In the present manuscript, the molecular mechanisms underlying HO-1 induction by LNO 2 were examined in HAEC (human aortic endothelial cells), HEK-293 (human embryonic kidney 293) cells, and in transcription factor-deficient MEF (mouse embryonic fibroblasts). LNO 2 induced HO-1 expression in Nrf2 [NF-E2 (nuclear factor-erythroid 2)-related factor 2]-deficient MEF and in HEK-293 cells transfected with Nrf2-specific shRNA (small-hairpin RNA), supporting the fact that LNO 2 -mediated HO-1 induction can be regulated by Nrf2-independent mechanisms. LNO 2 activated expression of a ―4.5 kb human HO-1 promoter construct, whereas a - 4.0 kb construct with deletion of 500 bp from the 5' region was unresponsive. Site-directed mutagenesis of a CRE (cAMP-response element) or of a downstream NF-E2/ AP-1 (activating protein-1) element, individually, within this 500 bp region modestly reduced activation of the HO-1 promoter by LNO 2. Mutations of both the CRE and the NF-E2/AP-1 site also attenuated LNO 2 -mediated HO-1 promoter expression, whereas the addition of a third mutation in the proximal E-box sequence completely abolished LNO 2 -induced HO-1 expression. Chromatin immunoprecipitation assays confirmed CREB (CREbinding protein)-1 binding to the CRE (located at ― 4.0 kb) and E-box regions (located at ― 44 bp) of the human HO-1 promoter. A 3C (Chromosome Conformation Capture) assay of intact cells showed LNO 2 -induced interactions between the CRE- and E-box-containing regions. These observations indicate that regulation of human HO-1 expression by LNO 2 requires synergy between CRE, AP-1 and E-box sequences and involves the participation of CREB-1. |
| Databáze: | OpenAIRE |
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