Research Article

Proinflammatory Cytokines Increase Vascular Endothelial Growth Factor Expression in Alveolar Epithelial Cells

Figure 3

Western blots of VEGF protein expression. All proteins were reduced so that VEGF runs in monomeric form. (a) Time course (hours) of expression as fold-change after stimulation of cultured A549 cells with TNF-α and IL-1, showing increased protein expression of a single 21 kDa band corresponding to VEGF165 with TNF-α stimulation but not after IL-1 stimulation (compared to time zero). A VEGF165 standard (10 ng) was loaded in the leftmost lane “VEGF” and the contiguous lane is empty “E” for each condition. Blots were stripped and reprobed for β-actin expression. Results are expressed as fold-change compared to time zero, normalized to β-actin. (b) A human lung homogenate contains the 3 common VEGF isoforms, although only VEGF165 and VEGF121 appear as prominent bands (lanes 6–8). Lanes 1–4 contain a recombinant VEGF165 standard, and lane 5 is empty. Molecular weight is denoted at left. All blots are representative of 5 experiments for each condition. , .