Premium
Expression and activity of C/EBPβ and δ are upregulated by dexamethasone in skeletal muscle
Author(s) -
Yang Hongmei,
Mammen Joshua,
Wei Wei,
Menconi Michael,
Evenson Amy,
Fareed Moin,
Petkova Victoria,
Hasselgren PerOlof
Publication year - 2005
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.20278
Subject(s) - myogenesis , skeletal muscle , electrophoretic mobility shift assay , dexamethasone , downregulation and upregulation , microbiology and biotechnology , ccaat enhancer binding proteins , luciferase , gene expression , medicine , transfection , chemistry , endocrinology , myocyte , reporter gene , transcription factor , biology , gene , dna binding protein , biochemistry
The influence of glucocorticoids on the expression and activity of the transcription factors CCAAT/enhancer binding protein (C/EBP)β and δ in skeletal muscle was examined by treating rats or cultured L6 myotubes with dexamethasone. Treatment of rats with 10 mg/kg of dexamethasone resulted in increased C/EBPβ and δ DNA binding activity in the extensor digitorum longus muscle as determined by electrophoretic mobility shift assay (EMSA) and supershift analysis. A similar response was noticed in dexamethasone‐treated myotubes. In other experiments, myocytes were transfected with a plasmid containing a promoter construct consisting of multiple C/EBP binding elements upstream of a luciferase reporter gene. Treatment of these cells with dexamethasone resulted in a fourfold increase in luciferase activity, suggesting that glucocorticoids increase C/EBP‐dependent gene activation in muscle cells. In addition, dexamethasone upregulated the protein and gene expression of C/EBPβ and δ in the myotubes in a time‐ and dose‐dependent fashion as determined by Western blotting and real‐time PCR, respectively. The results suggest that glucocorticoids increase C/EBPβ and δ activity and expression through a direct effect in skeletal muscle. © 2005 Wiley‐Liss, Inc.