Figure 4.

TGF-β-signaling pathways are involved in the inhibition of airway epithelial cell proliferation in the airway fragment model. a: Immunostaining of TGF-β1 and TGF-β3 of bronchial fragments at day 1 of culture. TGF-β3 staining (bottom) is intense compared to TGF-β1 (top). The area between the arrows is the new epithelium. v indicates a vessel. b: Real-time PCR of bronchial fragments for TGF-β1, -β2, and -β3. Shown is the approximate transcript copy number. Bar indicates mean values. Each square or diamond represents a single fragment, n = 8. All fragments were obtained from the same patient. c: Neutralizing anti-TGF-β Abs significantly increase cell proliferation in three sequential experiments. Each experiment represents fragments obtained from a different patient. Each circle represents a single fragment. The bar indicates the mean value. *, P < 0.001. d: Antibodies to β8 block release of active TGF-β by bronchial fragments. Bronchial fragments were treated with or without anti-β8 or anti-TGF-β and co-cultured overnight with mink lung epithelial cells stably expressing firefly luciferase cDNA under the transcriptional control of the TGF-β-responsive, plasminogen-activator inhibitor promoter. 20 Each data point represents four fragments. Data are pooled from fragments obtained from two patients. Shown are relative luminescence units. *, No treatment versus anti-β8 or anti-TGF-β, P < 0.001. Scale bar, 50 μm.