[Expression of cellular phenotype switching markers-matrix protein Gla, mRNA and collagen I, III and V of human airway smooth muscle cells in vitro after TGF-beta1 stimulation].
OBJECTIVE
Bronchial asthma is a chronic inflammatory disorder. Long-term inflammation leads to varying degrees of structural changes in the airway wall known as airway reconstruction or remodeling. These structural changes are found in the airways of most patients with prolonged disease. After remodeling, the airway walls show the submucous membrane becomes thick with collagen deposition, and the smooth muscle cells show hyperplasia and hypertrophy. Smooth muscle cells are a vital component of the airway wall, and a major effector cell involved in the course of bronchial contraction. Smooth muscle cell hyperplasia and hypertrophy are important pathological changes in airway remodeling. This study investigated the expression of markers of human airway smooth muscle cells (ASMCs) phenotypic change, which were matrix Gla protein (MGP) and major fibrosis proteins, after in vitro treatment with transforming growth factor-beta(1) (TGF-beta(1)).


METHODS
Human ASMCs were subjected to primary culture in vitro. Ten groups of cells were treated with 100 microg/ml of TGF-beta(1), while the cells in the control groups were treated with 10% fetal bovine serum. After being cultured for 7 d, the cells of both groups were harvested. MGP mRNA expression was detected by RT-PCR. Protein levels of collagen I, III and V were determined by Western blot analysis.


RESULTS
Treated with TGF-beta(1), airway smooth muscle cells expressed MGP mRNA greater than controls [(62.3 +/- 13.1)% vs (27.4 +/- 11.4)%, P < 0.01]. Also, airway smooth muscle cells stimulated by TGF-beta(1) produced more collagen I, III and V than the control group (P < 0.01).


CONCLUSIONS
TGF-beta(1) induced expression of collagen III and V, which are early markers of the switch from a contractile to a synthetic phenotype in ASMCs. This induction is an indication that ASMCs have the potential to make this switch and that TGF-beta(1) is involved in airway remodeling.
Shao
Jie
J
Department of Pediatrics, Ruijin Hospital, Shanghai Jiaotong University Medical College, Shanghai 200025, China.
Xia
Zhen-wei
ZW
Li
Yun-zhu
YZ
Yu
Shan-chang
SC
Deng
Wei-wu
WW
D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D001980:Bronchi / Q000166:cytology*; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism*; D024061:Collagen Type III / Q000378:metabolism*; D024062:Collagen Type V / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*; D000097568:Matrix Gla Protein
D015415:Biomarkers; D002135:Calcium-Binding Proteins; D024042:Collagen Type I; D024061:Collagen Type III; D024062:Collagen Type V; D016326:Extracellular Matrix Proteins; D012333:RNA, Messenger; D053773:Transforming Growth Factor beta1; D000097568:Matrix Gla Protein