Figure 2. Integrin α₉β₁ plays a protection role in airway hyperresponsiveness.

(A) Airway responsiveness to acetylcholine (Ach), measured in anesthetized, ventilated α₉smKO mice or littermate controls using a Scireq pulmonary mechanics analyzer. (B) Airway hyperresponsiveness in Itga9^+/– and Itga9^+/+ mice. (C) Series of phase-contrast images demonstrating the resting and contractile states of the airway upon exposure to various concentration of methacholine (Mch). Scale bar: 100 μm. (D) Airway narrowing in lung slices from WT control or α₉smKO mice in response to a range of concentrations of methacholine. (E) Airway narrowing in lung slices from Itga9^fl/fl mice on day 3 after infection with adenovirus expressing Cre recombinase or GFP (as control). (F) Airway narrowing in lung slices from WT mice treated in vitro with blocking antibody or control hamster antibody. Results (mean ± SEM) are representative of 3 independent experiments (n = 8). *P < 0.05; **P < 0.01.