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