Dose-Dependent Glucocorticoid Regulation of Transcription Factors in Vocal Fold Fibroblasts and Macrophages

Objective: Variable outcomes of glucocorticoid (GC) therapy for laryngeal disease are putatively due to diverse interac-tions of the GC receptor (GR) with cell signaling pathways, limited consideration regarding concentration-dependent effects, and inconsistent selection of GCs. In the current study, we evaluated the concentration-dependent effects of three frequently administered GCs on transcription factors with an emphasis on the phosphorylation of GR at Ser203 and Ser211 regulating the nuclear translocation of GR. This study provides foundational data regarding the diverse functions of GCs to optimize therapeu-tic approaches.Study design: In vitro.Methods: Human vocal fold fibroblasts and THP1-derived macrophages were treated with different concentrations of dexamethasone, methylprednisolone, and triamcinolone in combination with IFN-gamma, TNF-alpha, or IL4. Phosphorylated STAT1, NF-kappa B family molecules, and phosphorylated STAT6 were analyzed by Western blotting. Ser211-phosphorylated GR (S211-pGR) levels relative to GAPDH and Ser203-phosphorylated GR (S203-pGR) were also analyzed.Results: GCs differentially altered phosphorylated STAT1 and NF-kappa B family molecules in different cell types under IFN-gamma and TNF-alpha stimuli. GCs did not alter phosphorylated STAT6 in IL4-treated macrophages. The three GCs were nearly equivalent. A lower concentration of dexamethasone increased S211-pGR/GAPDH ratios relative to increased S211-pGR/S203-pGR ratios regardless of cell type and treatment.Conclusion: The three GCs employed in two cell lines had nearly equivalent effects on transcription factor regulation. Rel-atively high levels of Ser203-phosphorylation at low GC concentrations may be related to concentration-dependent differential effects of GCs in the two cell lines.