Involvement of fibronectin and matrix metalloproteinases in airway smooth muscle cell migration for the process of airway remodeling.
BACKGROUND
Airway remodeling is a repair process occurring after airway injury; its primary histopathological features are subepithelial fibrosis and smooth muscle thickening of the bronchi. These histopathological changes are considered to occur due to bronchial smooth muscle cells (bSMC) that secrete extracellular matrix (ECM) proteins, which work as chemoattractants and influence cell migration. Therefore, we examined the interaction between bSMCs and ECM proteins in vitro for understanding the remodeling process in the bronchi.


METHODS
bSMCs were cultured to collect a bSMC-conditioned medium. Using the bSMC-conditioned medium thus obtained, we performed a cell migration assay, characterized beta integrin expression, and identified ECM proteins and matrix metalloproteinases by western blotting and gelatin zymography, respectively.


RESULTS
The response of bSMC migration to bSMC-conditioned medium increased with time in culture, and fibronectin (FIB) was detected as a chemoattractant for bSMCs in bSMC-conditioned medium by western blot analysis and a cell migration assay using anti-FIB antibodies. The involvement of beta1 integrin in the migration of bSMCs toward FIB contained in bSMC-conditioned medium was demonstrated by inhibition of cell migration using anti-beta1 integrin antibodies. Expression of beta1 integrin on bSMCs was confirmed by using a beta-integrin-mediated cell adhesion array. In addition, metalloproteinases detected in bSMC-conditioned medium by gelatin zymography were suggested to be matrix metalloproteinase-1 and 2 by western blotting and amino acid sequencing.


CONCLUSIONS
Our results suggest that FIB and matrix metalloproteinases secreted from bSMCs might play major roles in bSMC migration in the process of airway remodeling.
Nishihara-Fujihara
Machiko
M
Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology,; Present address: Department of Dermatology, Kurume University School of Medicine, Fukuoka. Electronic address: fujihara_machiko@med.kurume-u.ac.jp.
Shoji
Shunsuke
S
Clinical Research Center, National Hospital Organization Tokyo National Hospital, Tokyo, Japan.
Maeda
Iori
I
Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology.
Shimoda
Terufumi
T
Clinical Research Center, National Hospital Organization Fukuoka National Hospital.
Nishima
Sankei
S
Clinical Research Center, National Hospital Organization Fukuoka National Hospital.
Okamoto
Kouji
K
Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology.
D056151:Airway Remodeling; D019138:Antibodies, Blocking / Q000494:pharmacology; D001980:Bronchi / Q000473:pathology; D054443:Cell Migration Assays; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D005353:Fibronectins / Q000378:metabolism*; D005355:Fibrosis; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism*; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000473:pathology
D019138:Antibodies, Blocking; D017077:Culture Media, Conditioned; D005353:Fibronectins; D019012:Integrin beta1; D020778:Matrix Metalloproteinase 2; D020781:Matrix Metalloproteinase 1