Figure 7.

Melittin inhibits IL-4/IL-13-induced pSTAT3 activation and filaggrin deficiency in HaCaT cells. (a) CCK-8 assay results show the cytotoxic effect of melittin on HaCaT cells. The HaCaT cells were treated with 0.1, 0.5, 1, and 2 μg ml⁻¹ of melittin, or 50 ng ml⁻¹ each of IL-4 and IL-13 for 24 and 48 h. Results are expressed as means ± SEM of three independent determinations. *p < 0.05 compared with the NC group. (b) Representative cropped Western blot images show that melittin inhibited the IL-4/IL-13-induced protein expressions of pSTAT3, and it also improved IL-4/IL-13-induced filaggrin deficiency in the HaCaT cells. GAPDH was presented as loading control. The samples were derived from the same experiment and that blots were processed in parallel. +: treated; −: untreated. Full-length the blots can be found in Supplementary Fig. S1b. (c) The bar graph shows the quantitative signal intensity of filaggrin and pSTAT3 after normalization with GAPDH and STAT3, respectively. (d) Representative immunofluorescence images show the effect of melittin on the IL-4/IL-13-induced activation of pSTAT3 (labeled with Alexa Fluor 555, red). β-actin was labeled with Alexa Fluor 488 (green). The nuclei were labeled with Hoechst 33342 (blue). All the scale bars in the images are 10 μm. NC: normal control; IL-4/IL-13: 50 ng ml⁻¹ each of IL-4 and IL-13; Mel: 1 μg ml⁻¹ of melittin; 1200×: 1,200-fold magnification.