Effect of PIGF dose on mRNA expression of cytochemokines and stability of TNF-α mRNA. (A) Dose-dependent increase in the expression of cytochemokines in PlGF-treated THP-1 cells: THP-1 cells were treated with different concentrations of PlGF ranging from 25 to 250 ng/mL for 2 hours. RNA was isolated by TriZOL reagent, and 10 μg RNA was used for RPA analysis. (B) Effect of PlGF on the stability of TNF-α mRNA. After the treatment of THP-1 cells with PlGF (250 ng/mL) for 2 hours, actinomycin D (10 μg/mL) was added. At the indicated times, RNA was isolated. TNF-α mRNA expression was determined by RPA as described in Figure 2. The relative mRNA levels were determined by normalizing band intensities of TNF-α with that of GAPDH housekeeping gene. Representative data are shown from 2 experiments.