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Objective To explore the mechanism of hypoxia on the expressions of airway remodeling-associated factors matrix metalloproteinase-9(MMP-9)and transforming growth factor β1(TGF-β1)in human airway epithelial cells(16HBE)under hypoxia.Methods We cultured 16HBE cells under normoxia or hypoxia (20 mL/L O2)for 6,12 and 24 hours.MMP-9 and TGF-β1with higher expression were pretreated with epidermal growth factor receptor(EGFR)inhibitor AG1478 and hypoxia-inducible factor-1α(HIF-1α)inhibitor Lificiguat (YC-1).Cell survival rate was measured by CCK-8 method.The mRNA levels of MMP-9 and TGF-β1were detected by RT-PCR.The levels of HIF-1α,MMP-9 and TGF-β1protein expressions were measured by Western blot. Results In hypoxia group,the levels of MMP-9 and TGF-β1mRNA as well as protein expressions increased compared with those in the control group(all P＜ 0.05).Pretreatment with AG1478 and YC-1 could inhibit the above-mentioned changes(P＜ 0.05).AG1478 suppressed the high expression of HIF-1α induced by hypoxia. Conclusion Hypoxia can up-regulate the expressions of airway remodeling-associated factors MMP-9 and TGF-β1 via EGFR's induction of HIF-α signaling pathway.
Résumé
<p><b>OBJECTIVE</b>To explore the role of transient receptor potential canonical 1 (TRPC1) in airway remodeling and the effect of budesonide intervention on its expression in the lungs of guinea pigs with ovalbumin-induced asthma.</p><p><b>METHODS</b>Fifty male guinea pigs were randomized into 5 equal groups, including a blank control group, ovalbumin group, ovalbumin+TRPC1 siRNA group, ovalbumin+luciferase siRNA group, and ovalbumin+budesonide group. After corresponding treatments, bronchoalveolar lavage was collected from the guinea pigs for eosinophils analysis and detection of IL-5 and IL-13 levels using ELISA. The lung tissues were stained with HE and Masson's trichrome to observe the bronchial wall thickness, smooth muscle hypertrophy, subepithelial collagen deposition, and lung inflammations. Immunohistochemistry and real-time quantitative PCR were performed to detect TRPC1 protein and mRNA expressions in the lungs, respectively.</p><p><b>RESULTS</b>The guinea pig models of ovalbumin-induced asthma showed significantly increased thickness of the bronchial wall, smooth muscle hypertrophy, collagen deposition and inflammatory cell infiltration, but these pathologies were obviously alleviated by treatment with TRPC1 siRNA or budesonide (P/0.05). Immunohistochemstry showed that TRPC1 protein was distributed mainly on the cell membrane and in the nuclei of the basal cells or columnar epithelial cells.</p><p><b>CONCLUSION</b>The up-regulated expression of TRPC1 ion channel is closely associated with the occurrence and progression of airway remodeling and chronic airway inflammation in asthma. Budesonide can partially suppress airway remodeling and inflammation by regulating the expression of TRPC1.</p>