Fig. 8.

Overexpressing human growth differentiation factor 15 (GDF15) enhances activation of Smad1 and interferon regulatory factor 7 (IRF7) in mouse airway epithelial cells. Primary tracheal epithelial cells from naïve human GDF15 transgenic (hGDF15 Tg+) mice or wild-type (WT) littermates were grown at air-liquid interface and infected with HRV-1B [multiplicity of infection (MOI) 1] or PBS (control) for 24 h. A, left: quantitative Western blot densitometry data of phosphorylated-Smad1 (pSmad1) and total Smad1 protein. A, right: representative Western blot pictures; B, left: quantitative Western blot densitometry data of IRF7 and β-actin protein (loading control). B, right: representative Western blot pictures. Data are presented as means ± SE from three independent experiments. *P < 0.05, **P < 0.01, compared with PBS controls or HRV-infected WT cells.