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Reduced transforming growth factor β1 (TGF‐β1) in the repair of airway epithelial cells of children with asthma
Author(s) -
Ling KakMing,
Sutanto Erika N.,
Iosifidis Thomas,
KicicStarcevich Elizabeth,
Looi Kevin,
Garratt Luke W.,
Martinovich Kelly M.,
Lannigan Francis J.,
Knight Darryl A.,
Stick Stephen M.,
Kicic Anthony
Publication year - 2016
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/resp.12810
Subject(s) - gene knockdown , small interfering rna , medicine , transforming growth factor , messenger rna , asthma , integrin , gene expression , immunology , cancer research , microbiology and biotechnology , andrology , gene , rna , biology , receptor , biochemistry
Abstract Background and objective Evidence into the role of TGF‐β1 in airway epithelial repair in asthma is still controversial. This study tested the hypothesis that the reduced TGF‐β1 levels previously observed in paediatric asthmatic airway epithelial cells directly contribute to the dysregulated repair seen in these cells. Methods Primary airway epithelial cells (pAEC) from children with asthma ( n = 16) and non‐asthmatic subjects ( n = 20) were isolated, and subcultured for investigation of TGF‐β1 gene and protein via quantitative polymerase chain reaction (qPCR) and enzyme‐linked immunosorbent assay (ELISA), respectively. Expression of other associated genes such as integrins αvβ6, αvβ8 and MT1‐MMP were also tested. Small interfering RNA (siRNA) was employed to assess the role of TGF‐β1 during wound repair. Results TGF‐β1 gene and protein expression were significantly downregulated in asthmatic pAEC over the course of repair, compared with cells from non‐asthmatic children. Messenger RNA (mRNA) expression of TGF‐β1 was also directly implicated in non‐asthmatic and asthmatic pAEC proliferation over their quiescent counterparts. Small interfering RNA‐mediated knockdown of TGF‐β1 compromised repair in non‐asthmatic pAEC and exacerbated the dysregulated repair seen in asthmatic pAEC. Expression of major TGF‐β1 activators of epithelial cells, integrin αvβ6 and αvβ8 was also measured and there was no difference in αvβ6 gene expression between the two cohorts. Although integrin αvβ8 gene expression was significantly higher in asthmatic pAEC, the expression of MT1‐MMP (MMP14) which facilitates the αvβ8 mediated TGF‐β1 activation was significantly downregulated. Conclusion Our data has highlighted the importance of TGF‐β1 in pAEC wound repair in vitro . The significantly lower levels seen in asthmatic pAEC subsequently contributes to the dysregulated repair observed in these cells.