Curcumin Inhibits NTHi-Induced MUC5AC Mucin Overproduction in Otitis Media via Upregulation of MAPK Phosphatase MKP-1

Figure 2

Curcumin suppresses NTHi-induced MUC5AC expression via inhibition of p38 MAPK. (a) HMEECs were transfected with Mock, MKK3-CA, or MKK6-CA plasmids. Cells were treated with 20 μM curcumin for 1 h, and MUC5AC mRNA expression was measured. (b) HMEECs were pretreated with 20 μM curcumin and 10 μM SB203580 for 1 h, followed by stimulation with NTHi for 5 h, and MUC5AC mRNA expression was measured. (c) HMEECs were transfected with Mock, p38α-DN, or p38β-DN plasmids. Cells were pretreated with curcumin (20 μM) for 1 h, followed by NTHi stimulation for 5 h and MUC5AC mRNA expression was measured. (d) HMEECs were transfected with wild-type MUC5AC promoter, distal AP-1 mutant MUC5AC promoter, or proximal AP-1 mutant MUC5AC promoter containing luciferase vectors. Cells were pretreated with 20 μM curcumin for 1 h, followed by NTHi stimulation for 5 h. MUC5AC promoter-driven luciferase activity was measured. Data are mean s.d. (). (a) , -test. (b)–(d) , ANOVA (Tukey’s post hoc). n.s., not significant. Data are representative of three or more independent experiments.

(a)

(b)

(c)

(d)