ABSTRACT
Airway remodeling is an important pathological feature of asthma and the basis of severe asthma. Proliferation of airway smooth muscle cells (ASMCs) is a major contributor to airway remodeling. As an important Ca(2+) channel, transient receptor potential vanilloid 1 (TRPV1) plays the key role in the cell pathological and physiological processes. This study investigated the expression and activity of TRPV1 channel, and further clarified the effect of TRPV1 channel on the ASMCs proliferation and apoptosis in order to provide the scientific basis to treat asthmatic airway remodeling in clinical practice. Immunofluorescence staining and reverse transcription polymerase chain reaction (RT-PCR) were used to detect the expression of TRPV1 in rat ASMCs. Intracellular Ca(2+) was detected using the single cell confocal fluorescence microscopy measurement loaded with Fluo-4/AM. The cell cycles were observed by flow cytometry. MTT assay and Hoechst 33258 staining were used to detect the proliferation and apoptosis of ASMCs in rats respectively. The data showed that: (1) TRPV1 channel was present in rat ASMCs. (2) TRPV1 channel agonist, capsaicin, increased the Ca(2+) influx in a concentration-dependent manner (EC50=284.3±58 nmol/L). TRPV1 channel antagonist, capsazepine, inhibited Ca(2+) influx in rat ASMCs. (3) Capsaicin significantly increased the percentage of S+G2M ASMCs and the absorbance of MTT assay. Capsazepine had the opposite effect. (4) Capsaicin significantly inhibited the apoptosis, whereas capsazepine had the opposite effect. These results suggest that TRPV1 is present and mediates Ca(2+) influx in rat ASMCs. TRPV1 activity stimulates proliferation of ASMCs in rats.
Subject(s)
Animals , Rats , Antipruritics , Pharmacology , Apoptosis , Physiology , Bronchi , Cell Biology , Metabolism , Calcium Signaling , Physiology , Capsaicin , Pharmacology , Cell Proliferation , Myocytes, Smooth Muscle , Cell Biology , Metabolism , Rats, Sprague-Dawley , TRPV Cation Channels , MetabolismABSTRACT
Airway remodeling is an important pathological feature of asthma and the basis of severe asthma. Proliferation of airway smooth muscle cells (ASMCs) is a major contributor to airway remodeling. As an important Ca(2+) channel, transient receptor potential vanilloid 1 (TRPV1) plays the key role in the cell pathological and physiological processes. This study investigated the expression and activity of TRPV1 channel, and further clarified the effect of TRPV1 channel on the ASMCs proliferation and apoptosis in order to provide the scientific basis to treat asthmatic airway remodeling in clinical practice. Immunofluorescence staining and reverse transcription polymerase chain reaction (RT-PCR) were used to detect the expression of TRPV1 in rat ASMCs. Intracellular Ca(2+) was detected using the single cell confocal fluorescence microscopy measurement loaded with Fluo-4/AM. The cell cycles were observed by flow cytometry. MTT assay and Hoechst 33258 staining were used to detect the proliferation and apoptosis of ASMCs in rats respectively. The data showed that: (1) TRPV1 channel was present in rat ASMCs. (2) TRPV1 channel agonist, capsaicin, increased the Ca(2+) influx in a concentration-dependent manner (EC50=284.3±58 nmol/L). TRPV1 channel antagonist, capsazepine, inhibited Ca(2+) influx in rat ASMCs. (3) Capsaicin significantly increased the percentage of S+G2M ASMCs and the absorbance of MTT assay. Capsazepine had the opposite effect. (4) Capsaicin significantly inhibited the apoptosis, whereas capsazepine had the opposite effect. These results suggest that TRPV1 is present and mediates Ca(2+) influx in rat ASMCs. TRPV1 activity stimulates proliferation of ASMCs in rats.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the relationship between the proliferation of sensitized human airway smooth muscle cells (HASMCs) and the expression of extracellular signal regulated kinase (ERK) and the effect of Shenmai Injection (SMI) on HASMCs.</p><p><b>METHODS</b>The HASMCs cultured in vitro were divided into three groups: (1) control group; (2) sensitized group: containing 10% asthmatic serum; (3) SMI group: further divided into three different concentration subgroups interferred with 10 microL/mL, 50 microL/mL, and 100 microL/mL SMI, respectively. The proliferation of HASMCs was detected using MTT method, the expression of proliferating cell nucleus antigen (PCNA) in HASMCs was detected using immunocytochemical staining, and the expression of phosphoration-ERK1/2 (p-ERK1/2) protein was detected using Western-blot.</p><p><b>RESULTS</b>After passive sensitization,: the optical density value (A A(490) value) of HASMCs was significantly increased from 0.366+/-0.086 to 0.839+/- 0.168 (P<0.05). In addition, the expression of PCNA was significantly increased from 28.7%+/-5.9% in the control group to 69.8%+/-7.5% in the sensitized group (P<0.05). At the same time, the expression of p-ERK1/2 in passively sensitized HASMCs was significantly increased compared with the control group (all P<0.05). After application of 10 microL/mL, 50 microL/mL, and 100 microL/mL SMI to the cultured media of passively sensitized group, the A(570) value was significantly decreased from 0.839+/-0.168 to 0.612+/-0.100, 0.412+/-0.092, and 0.339+/-0.077, respectively (P<0.05). Moreover, the expression of PCNA was significantly decreased from 69.8%+/-7.5% to 57.8%+/-6.2%, 40.7%+/-5.4%, and 26.1%+/-5.2%, respectively. At the same time, the expression of p-ERK1/2 in each SMI group was significantly decreased compared with the sensitized group (all P<0.05).</p><p><b>CONCLUSION</b>ERK signal transduction pathway may be involved in the airway remodeling in asthma. The expression of ERK can be inhibited by SMI in a dose-dependent manner, thus preventing the proliferation of HASMCs.</p>