Inhibition of corticosteroid-binding globulin gene expression by glucocorticoids involves C/EBPβ.
Corticosteroid-binding globulin (CBG), a negative acute phase protein produced primarily in the liver, is responsible for the transport of glucocorticoids (GCs). It also modulates the bioavailability of GCs, as only free or unbound steroids are biologically active. Fluctuations in CBG levels therefo...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2014-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC4205011?pdf=render |
| _version_ | 1817990151981236224 |
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| author | Nicolette Verhoog Fatima Allie-Reid Wim Vanden Berghe Carine Smith Guy Haegeman Janet Hapgood Ann Louw |
| author_facet | Nicolette Verhoog Fatima Allie-Reid Wim Vanden Berghe Carine Smith Guy Haegeman Janet Hapgood Ann Louw |
| author_sort | Nicolette Verhoog |
| collection | DOAJ |
| description | Corticosteroid-binding globulin (CBG), a negative acute phase protein produced primarily in the liver, is responsible for the transport of glucocorticoids (GCs). It also modulates the bioavailability of GCs, as only free or unbound steroids are biologically active. Fluctuations in CBG levels therefore can directly affect GC bioavailability. This study investigates the molecular mechanism whereby GCs inhibit the expression of CBG. GCs regulate gene expression via the glucocorticoid receptor (GR), which either directly binds to DNA or acts indirectly via tethering to other DNA-bound transcription factors. Although no GC-response elements (GRE) are present in the Cbg promoter, putative binding sites for C/EBPβ, able to tether to the GR, as well as HNF3α involved in GR signaling, are present. C/EBPβ, but not HNF3α, was identified as an important mediator of DEX-mediated inhibition of Cbg promoter activity by using specific deletion and mutant promoter reporter constructs of Cbg. Furthermore, knockdown of C/EBPβ protein expression reduced DEX-induced repression of CBG mRNA, confirming C/EBPβ's involvement in GC-mediated CBG repression. Chromatin immunoprecipitation (ChIP) after DEX treatment indicated increased co-recruitment of C/EBPβ and GR to the Cbg promoter, while C/EBPβ knockdown prevented GR recruitment. Together, the results suggest that DEX repression of CBG involves tethering of the GR to C/EBPβ. |
| first_indexed | 2024-04-14T00:55:06Z |
| format | Article |
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| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-04-14T00:55:06Z |
| publishDate | 2014-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-0ae8bc14c40840db8f921502d402b6c92022-12-22T02:21:37ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-01910e11070210.1371/journal.pone.0110702Inhibition of corticosteroid-binding globulin gene expression by glucocorticoids involves C/EBPβ.Nicolette VerhoogFatima Allie-ReidWim Vanden BergheCarine SmithGuy HaegemanJanet HapgoodAnn LouwCorticosteroid-binding globulin (CBG), a negative acute phase protein produced primarily in the liver, is responsible for the transport of glucocorticoids (GCs). It also modulates the bioavailability of GCs, as only free or unbound steroids are biologically active. Fluctuations in CBG levels therefore can directly affect GC bioavailability. This study investigates the molecular mechanism whereby GCs inhibit the expression of CBG. GCs regulate gene expression via the glucocorticoid receptor (GR), which either directly binds to DNA or acts indirectly via tethering to other DNA-bound transcription factors. Although no GC-response elements (GRE) are present in the Cbg promoter, putative binding sites for C/EBPβ, able to tether to the GR, as well as HNF3α involved in GR signaling, are present. C/EBPβ, but not HNF3α, was identified as an important mediator of DEX-mediated inhibition of Cbg promoter activity by using specific deletion and mutant promoter reporter constructs of Cbg. Furthermore, knockdown of C/EBPβ protein expression reduced DEX-induced repression of CBG mRNA, confirming C/EBPβ's involvement in GC-mediated CBG repression. Chromatin immunoprecipitation (ChIP) after DEX treatment indicated increased co-recruitment of C/EBPβ and GR to the Cbg promoter, while C/EBPβ knockdown prevented GR recruitment. Together, the results suggest that DEX repression of CBG involves tethering of the GR to C/EBPβ.http://europepmc.org/articles/PMC4205011?pdf=render |
| spellingShingle | Nicolette Verhoog Fatima Allie-Reid Wim Vanden Berghe Carine Smith Guy Haegeman Janet Hapgood Ann Louw Inhibition of corticosteroid-binding globulin gene expression by glucocorticoids involves C/EBPβ. PLoS ONE |
| title | Inhibition of corticosteroid-binding globulin gene expression by glucocorticoids involves C/EBPβ. |
| title_full | Inhibition of corticosteroid-binding globulin gene expression by glucocorticoids involves C/EBPβ. |
| title_fullStr | Inhibition of corticosteroid-binding globulin gene expression by glucocorticoids involves C/EBPβ. |
| title_full_unstemmed | Inhibition of corticosteroid-binding globulin gene expression by glucocorticoids involves C/EBPβ. |
| title_short | Inhibition of corticosteroid-binding globulin gene expression by glucocorticoids involves C/EBPβ. |
| title_sort | inhibition of corticosteroid binding globulin gene expression by glucocorticoids involves c ebpβ |
| url | http://europepmc.org/articles/PMC4205011?pdf=render |
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