Figure 5: DEX synergistically enhances the NTHi-induced IRAK-M expression via IKKβ and GR.

(a) Immunoblot shows that IRAK-M protein expression in BEAS-2B cells treated with DEX (100 nM) and NTHi, TNF-α (10 ng ml⁻¹), IL-1β (1 ng ml⁻¹) or Pam3CSK4 (1 μg ml⁻¹). (b) IRAK-M mRNA expression assessed by qPCR in A549 cells transfected with constitutive active form of IKKβ (IKKβ CA) with DEX (100 nM). (c–f), IRAK-M expression in BEAS-2B cells treated with DEX (100 nM) and NTHi, IKKβ inhibitor (1 μM) (c,d) or RU486 (1 μM; e,f). (g) Immunoblot shows IRAK-M protein expression in BEAS-2B cells transfected with siRNA GR. (h) BEAS-2B cells were treated with NTHi, DEX (100 nM) and actinomycin D, ActD (5 μg ml⁻¹), followed by immunoblot. (i) The expression of IRAK-M mRNA in BEAS-2B cells treated with DEX (100 nM) and Compound A, CpdA (1 or 10 μM) followed by NTHi stimulation for 5 h. (j) Relative luciferase activity (RLA) of NF-κB is measured by luciferase assay. BEAS-2B cells transfected with NF-κB luciferase plasmid were treated with CpdA and NTHi. Data (b,c,e,i,j, n=3) are mean±s.d. *P<0.05, NS; t-test.