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

Figure 3

Curcumin inhibits NTHi-induced MUC5AC expression via upregulation of MKP-1 phosphatase. (a) HMEECs were pretreated with curcumin (20 μM) for 1 h; followed by NTHi stimulation for 1 h. MKP-1 protein (Alexa 488) was visualized by immunofluorescence staining. DAPI, nuclear stain. Original magnification: 400x. Scale bar, 20 μm. (b) HMEECs were treated with 20 μM curcumin, 5 μg/ml Actinomycin D (ACT-D), or both for 1 h, followed by stimulation with NTHi for 1 h, and MKP-1 mRNA expression was measured. (c, d) HMEECs were transfected with (c) Mock or myc-MKP-1, (d) Mock or MKP-1 shRNA. Cells were stimulated with NTHi for 5 h, and MUC5AC mRNA expression was measured. MKP-1 knockdown was confirmed by Q-PCR. (e) HMEECs were transfected with Mock or MKP-1 shRNA plasmid. Cells were pretreated with 20 μM curcumin for 1 h, followed by NTHi stimulation for 5 h, and MUC5AC mRNA expression was measured. (b, e) , ANOVA (Tukey’s post hoc). (c, d) , -test. n.s., not significant. Data are representative of three or more independent experiments.

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