FIG. 1.

Effect of activating transcription factor 3 (ATF3) on pro-inflammatory signaling in human epithelial cells. (A) Representative Western blot showing treatment of human distal bronchoalveolar small airway epithelial cells (Beas-2b) with lipopolysaccharide (LPS) (1 μg/ml, 24 h) results in increased ATF3 and ICAM-1 protein expression. Bar graphs represent densitometry analysis from three independent experiments (n=3, *p<0.05). Expression ratios were normalized to GAPDH. (B and D) ATF3 gene silencing exacerbates LPS-induced ICAM-1 and IL-8 protein expression. Beas-2b cells were infected with either Ad-shRNA (nontargeting shRNA) or Ad-shATF3 for 24 h and treated with or without LPS as earlier. ATF3 gene silencing results in increased ICAM-1 (B, Western blot) and IL-8 production in cell lysates (D, ELISA). (C and D) Overexpression of ATF3 mitigates ICAM-1 and IL8 production in response to LPS. Beas-2b cells were infected with Ad-βGal (control vector) and Ad-ATF3 (overexpression vector) and treated with LPS as earlier. Overexpression of ATF3 mitigates ICAM-1 expression (C, Western blot) and IL-8 production (D, ELISA). Bar graphs represent densitometry analysis from three independent experiments (n=3). Expression ratios were normalized to GAPDH. Data are expressed as SEM (n=3); *p<0.05 for the comparison between control and LPS treated; and # p<0.05 for the comparison between adenovirus treatment (sh-RNA vs. Ad-shATF3 or Ad-βGal vs. Ad-ATF3).