Fig. 9.

LPS and TLR4 induce transforming growth factor (TGF)-β expression in STC-1 cells. A: STC-1 cells were grown in 1% FBS and stimulated with 10 μg/ml LPS for 0–6 h. Total RNA was isolated and reverse transcribed. TGF-β and β-actin primer sequences are described in MATERIALS AND METHODS. Experiments were repeated 3 times, and a representative result is displayed. B: STC-1 cells were stimulated with 0.1–10 μg/ml LPS for 24, 48, or 72 h. ELISA was performed on the supernatants for TGF-β according to the manufacturer's protocols. Experiments were performed in triplicate, and results represent means ± SD. *P < 0.05 compared with unstimulated cells for each time group. C: constitutively active (ca)-TLR4 expression plasmid increased TGF-β production in transfected STC-1 cells. STC-1 cells were grown in 1% FBS and transfected with a total of 1 μg plasmid DNA (empty vector pcDNA3 + ca-TLR4). STC-1 cells were incubated for 48, 72, or 96 h. ELISA was performed on the supernatants for TGF-β according to the manufacturer's protocols. Experiments were performed in triplicate, and results represent means ± SD. *P < 0.05 compared with empty vector control for each time group.