TGFβ inhibits LPS-mediated KC mRNA stabilization in tet-off RAW264.7 cells. (A) tet-off RAW264.7 cells were transiently transfected with pTRE2/KCcDNA and after 3 hours were subcultured into separate dishes for individual treatments. After an additional 18 hours of rest, separate cultures were treated with Dox (100 ng/mL), LPS (10 ng/mL), or TGFβ (20 ng/mL) alone or in combination as indicated for 1, 2, or 4 hours. Total RNA was prepared and KC or GAPDH mRNA levels were determined by northern hybridization. (B) tet-off RAW264.7 cells transfected as above with pTRE2/KCcDNA were untreated (NT) or treated with LPS (10 ng/mL) or TGFβ (20 ng/mL) for 4 hours prior to analysis of KC mRNA levels. (C) tet-off RAW264.7 cells transfected with pTRE2/KCcDNA were untreated or treated with Dox or Dox + TGFβ for 1, 2, or 4 hours prior to analysis of KC mRNA levels by northern hybridization. Similar results were obtained in 2 separate experiments.