NRF2 Activation Inhibits Both TGF-β1- and IL-13-Mediated Periostin Expression in Fibroblasts: Benefit of Cinnamaldehyde for Antifibrotic Treatment

Figure 4

The involvement of NRF2 signaling in the downregulation of IL-13- and TGF-β1-induced periostin expression by cinnamaldehyde. (a, b) Knockdown of NRF2 reverses the effects of cinnamaldehyde (CIN) on TGF-β1-induced expression of periostin (POSTN) mRNA and protein. (c, d) Knockdown of NRF2 reverses the effects of CIN on IL-13-induced expression of POSTN mRNA and protein. NHDF cells were transiently transfected with control siRNA or NRF2 siRNA for 24 h; next, cells were precultured in 25 μM CIN for 30 min and then treated with 5 ng/mL TGF-β1 or 50 ng/mL IL-13 or left untreated for 48 h. Expression levels of POSTN mRNA and protein in the cell supernatants are depicted. The values were adjusted by GAPDH expression. The same experiments were performed three times. , . NS: not significant.

(a)

(b)

(c)

(d)