ABSTRACT
<p><b>OBJECTIVE</b>To investigate the role of TGF-beta(1)/MAPK signaling pathways in the expression of type I collagen and activity of MMP-2, 9 in human lung fibroblasts.</p><p><b>METHODS</b>Human lung fibroblasts cell line (HLF-02) was cultured and and then stimulated with 10 ng/ml TGF-beta(1) for different time; SB203580 or PD98059 was added into culture medium to block p38 or ERK kinase pathway before incubated with TGF-beta(1); the expression of type I collagen was detected by Western blotting and RT-PCR; zymogram analysis was used to analyze the activity of MMP-2 and MMP-9.</p><p><b>RESULTS</b>(1) In the process of stimulation by TGF-beta(1), the type I collagen mRNA level of 24 h, 48 h and 72 h group was: 1.33 +/- 0.07, 2.46 +/- 0.09 and 2.39 +/- 0.08 respectively; and the type I collagen protein level of 24 h, 48 h and 72 h group was: 114.89 +/- 8.95, 208.16 +/- 6.75 and 211.46 +/- 8.05 respectively; and the activity of MMP-2 of 24 h, 48 h and 72 h group was: 190.33 +/- 5.86, 214.33 +/- 8.39 and 212.67 +/- 11.59 respectively. (2) SB203580 significantly inhibited the TGF-beta(1)-induced expression of type I collagen mRNA, protein and MMP-2 activity (inhibition ratio: 51%, 24% and 20%); (3) PD98059 also significantly attenuated the TGF-beta(1)-induced expression of type I collagen mRNA, protein and MMP-2 activity (inhibition ratio: 42%, 13% and 16%).</p><p><b>CONCLUSION</b>TGF-beta(1) is capable of inducing the expression of type I collagen mRNA and protein and up-regulating MMP-2 activity in HLF-02 cells. p38 and ERK kinase signaling pathways play important role in regulation and control for this process.</p>
Subject(s)
Humans , Blotting, Western , Cell Line , Collagen Type I , Genetics , Extracellular Signal-Regulated MAP Kinases , Physiology , Fibroblasts , Metabolism , Flavonoids , Pharmacology , Imidazoles , Pharmacology , Lung , Cell Biology , Matrix Metalloproteinase 2 , Metabolism , Matrix Metalloproteinase 9 , Metabolism , Pyridines , Pharmacology , RNA, Messenger , Genetics , Reverse Transcriptase Polymerase Chain Reaction , Signal Transduction , Physiology , Transforming Growth Factor beta1 , Pharmacology , p38 Mitogen-Activated Protein Kinases , PhysiologyABSTRACT
<p><b>OBJECTIVE</b>To discuss the role of early growth response factor (Egr)-1 and it's upstream signaling pathway in the development of silicosis.</p><p><b>METHODS</b>The expression and localization of Egr-1 were analyzed by immunofluorescence and in-situ hybridization. The activity of Egr-1 was observed in treated cells by using a reporter plasmid and EMSA, the activity of ERK1/2 in RAW264.7 incubated with SiO(2) by using a kinase assay, and further by using a kinase inhibitor assay to investigate the role of upstream kinase in the signal pathway of the activation of Egr-1.</p><p><b>RESULTS</b>The obvious increase of expression and transcription of Egr-1 was observed shortly after being treated by silica and its activity increased abruptly. There was an increase of the activity of ERK1/2 in RAW264.7 cells treated, which reached a peak at 30 minutes. The expression and transcription of Egr-1 decreased maniferstly after using kinase inhibitors.</p><p><b>CONCLUSION</b>Egr-1 expression can be induced by silica dioxide in RAW264.7 cells, and the ERK1/2, p38 kinases may take part in this process which suggest the pathway of SiO(2), ERK1/2, p38 and Egr-1 may play an important role in the development of silicosis.</p>