Objective To screen the possible regulatory proteins showing the ability for interaction with serum response factor ( SRF) in the progress of myofibroblast activation, and to see if the proteinprotein interaction is contributing to induce the expression of smooth muscle αactin ( α-SMA) . Methods Phage display cDNA libraries were constructed from the transdifferentiated airway epithelial cells and parental cells. Phage clones were then selectively amplified during the biopanning procedure by using SRF as a bait protein for the two cDNA libraries. Following four rounds of biopanning, recovered cDNAs were sequenced and the obtained sequences were aligned by BLAST tool to select the candidate gene. PAI-RBP1 of the candidate gene was cloned and sub-cloned into pcDNA3. 0 plasmid. Transient transfection and RT-PCR analysis were performed for investigation of the expression of α-SMA. Results Three candidate proteinbinding partners, PAI-RBP1, Nucleolin, and HF1OO, were identified. Among them, PAI-RBP1 pcDNA3. 0 plasmid was subjected to transient co-transfection with SRF, showing up-regulation of α-SMA expression. Conclusions Combined with phage display technique, through protein-protein interaction between core transcription factor and unknown proteins to find a newtranscriptional regulator may serve as an effective strategy. Three novel SRF binding proteins were found from transdifferentiated cells. This study indicates that PAI-RBP1 involves in the activation of myofibroblast by induction of α-SMA expression.
Objective To evaluate the effects of two different epidermal growth factor receptor tyrosine kinase inhibitors ( EGFR-TKIs) , Gefitinib and Erlotinib, on lung fibrosis induced by bleomycin.Methods Forty BALB/c female mice were randomly divided into four groups, ie. a control group( saline given orally and intratracheally) , a fibrosis group( saline given orally with bleomycin instillation) , a Gefitnib group( Gefitnib 20 mg/kg given orally with bleomycin instillation) , and an Erlotinib group ( Erlotinib25 mg/kg given orally with bleomycin instillation) . Bleomycin ( 3 mg/kg) was intratracheally instilled on the first day. Gefitinib or Erlotinib was given orally daily and normal saline as control. Then they were sacrificed by abdominal aortic bleeding 14 days after the bleomycin instillation. The left lung was stained with HE and Masson’s trichrome staining respectively for pathological examination. Total EGFR and phosphorylated EGFR were detected by immunohistochemistry. Hydroxyproline ( HYP) assay was performed in the right lung.Results Both Gefitinib and Erlotinib significantly reduced lung collagen accumulation and the content of HYP. Immunohistochemistry revealed that phosphorylation of EGFR in lung mesenchymal cells induced by bleomycin was inhibited. Furthermore, there was no difference between Gefitinib and Erlotinib in inhibiting lung fibrosis. Conclusion Our findings suggest that, in the preclinical setting, EGFR-TKIs may have aprotective effect on lung fibrosis induced by bleomycin.
Objective To investigate the expression of fibroblast activation protein( FAP) in mouse pulmonary fibrosis and the relationship between FAP and trarisforming growth factor β1 ( TGF-β1 ) .Methods The mouse model with pulmonary fibrosis was established by intratracheally instillation of bleomycin. The expressions of FAP, α-smooth muscle action( α-SMA) , and TGF-β1 in lung tissues were detected with immunohistochemical technique. Results There was no expression of FAP in the normal lung tissue. In the pulmonary fibrosis mice, FAP was found in the fibroblasts existed in bronchiolar adventitia or peribronchiolar ( and perivascular) connective tissue. In the fibroblast foci, the localizations of α-SMA, TGF-β1 , and FAP were similar, but the expression of FAP was more extensive than that of α-SMA and ber than that ofTGF-β1 . The degree of lung fibrosis was bly correlated with FAP, α-SMA, and TGF-β1 ( r = 0. 795,0. 766,0. 628; P lt; 0. 01) . A significantly positive correlation was also observed between TGF-β1 and FAP( r =0. 706, P lt; 0. 01) . Conclusions FAP is especially expressed in the fibroblast foci in pulmonaryfibrosis and bly correlated with the severity of pulmonary fibrosis. FAP and TGF-β1 possibly play a synergistic role in the progression of pulmonary fibrosis.