Figure 4.

Knockdown of C/EBP-α and calmodulin enhances ASMC proliferation. Human ASMCs were transfected with calreticulin siRNA together with either C/EBP-α siRNA or control siRNA for 24 h and then stimulated with 10% CSE for 24 h prior to the following analyses. (A) Reverse transcription-quantitative polymerase chain reaction and (B) western blot analyses were performed to determine mRNA and protein levels of C/EBP-α in the ASMCs. (C) Immunostaining of human ASMCs was performed using antibody against C/EBP-α (red); nuclei were counter-stained with DAPI (blue). Magnification, ×200. (D) Cell proliferation was analyzed by MTT assay. (E) Cell apoptosis was analyzed using the FITC Annexin V/Dead Cell Apoptosis kit. (F) Bar chart showing the percentage of apoptotic cells after 10% CSE treatment for 24 h. *P<0.05 vs. control. AMSC, airway smooth muscle cell; C/EBPα, CCAAT/enhancer-binding protein α; CSE, cigarette smoke extract; siRNA, small interfering RNA; siRNA NC, scrambled control siRNA; FITC, fluorescein isothiocyanate; PI, propidium iodide.