Fig. 4.

Targeting PI3Kγ to attenuate IL-13-augmented contraction of primary mouse ASM cells. A, blockade of PI3Kγ attenuated IL-13-augmented contraction of mouse ASM cells. ASM cells were treated without (control) or with IL-13 (100 ng/ml) for 24 h. Cells were then exposed to 10 μM ACh in the presence of PI3Kγ inhibitor II (10 μM) or vehicle (0.1% DMSO). Representative images of an initial recording (None, 0 min) and after 5-min exposure to 10 μM ACh are shown on the left. The extent of contraction, calculated as the percentage change in cell-surface area, is shown on the right. Mouse ASM cells were also dual transfected with PI3Kγ siRNA or negative (Neg) siRNA for 48 h and treated without (control) or with IL-13 (100 ng/ml) for 24 h. B, Western blot analysis of PI3Kγ, PI3Kα, and β-actin expression levels in IL-13-treated mouse ASM cells (left), analyzed by measuring band density with β-actin as the normalizing control (right). Data represent means ± S.E. of three independent experiments performed in duplicate. C, siRNA-mediated knockdown of PI3Kγ inhibited IL-13-augmented ASM cell contraction in response to 10 μM ACh. Data in A and C are means ± S.E. and represent 50 cells from three separate experiments performed on multiple days. Statistical comparisons used ANOVA with the Bonferroni correction.