| 18070556 |
Chen XW, Xu J: [The pathologic significance and ionic mechanism of injured airway epithelium induced transdifferentiation of airway fibroblasts]. Zhonghua Jie He He Hu Xi Za Zhi. 2007 Sep;30(9):691-6.
OBJECTIVE: To investigate the effects of injured airway epithelial cells on the transdifferentiation of sub-epithelial fibroblasts, thus addressing the mechanisms of characteristic airway remodeling in asthmatic airway. METHODS: Human sub-epithelial fibroblasts (SEF) or SEF in collagen gels were co-cultured with culture dishes which containing or not containing bronchial epithelial cells (16HBE) for 4 days. The experiments were divided into 7 groups according to different treatment to 16HBE; Group A: culture dishes not containing 16HBE; Group B: culture dishes containing normal 16HBE; Group C: culture dishes containing 16HBE treated with mechanical scrape; Group D: culture dishes containing 16HBE treated with mechanical scrape plus LPS stimulation; Group E: culture dishes containing 16HBE pre-added with endothelin receptor A inhibitor (BQ123) followed by treatment with mechanical scrape plus LPS stimulation; Group F: culture dishes containing 16HBE pre-added with TGF-beta (1) neutralizing antibody followed by treatment with mechanical scrape plus LPS stimulation; Group G: culture dishes containing 16HBE pre-added with BQ123 plus TGF-beta (1) neutralizing antibody followed by treatment with mechanical scrape plus LPS stimulation. The expression of alpha-smooth muscle actin (alpha-SMA) in the SEF was assessed by immunofluorescence or Western blotting. The diameters of the collagen gels containing SEF (8 samples in each group) were measured. Moreover, SEF in group A, B or D were selected, and the dynamic changes of intracellular calcium concentration [Ca (2+)] i were observed (at least 6 cells were analyzed in each group) by laser co-focal microscopy in the transdifferentiated SEF in response to the stimulation of the supernatant of 16HBE treated with mechanical scrape plus LPS stimulation for 24 h. RESULTS: alpha-SMA expression in SEF was most abundant in group D compared with other groups. Relative contraction percentage was also significantly higher in group D [(53 +/- 8)%] than that in group B [(10 +/- 10)%], group C [(24 +/- 8)%], group E [(36 +/- 9)%], group F [(37 +/- 3)%] or group G [(31 +/- 7)%], respectively (F = 24.80, 38.10, all P < 0.01). Increased fluorescence intensity of [Ca (2+)] i was observed in the SEF stimulated with the supernatant of the injured 16HBE in all groups, which was significant in group D (F = 16.60, 8.97; all P < 0.01). CONCLUSIONS: Injured airway epithelial cells induced the transdifferentiation of SEF towards alpha-SMA-expressing and elevated contractible myofibroblasts, in which both ET-1 and TGF-beta (1) may play crucial roles. The supernatant of injured airway epithelial cells-induced influx of [Ca (2+)] i may be an early signal for initiating the increased contractility in the transdifferentiated SEF. |
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