Notch induces myofibroblast differentiation of alveolar epithelial cells via transforming growth factor-{beta}-Smad3 pathway

Kana Aoyagi-Ikeda, Toshitaka Maeno, Hiroki Matsui, Manabu Ueno, Kenichiro Hara, Yasuhiro Aoki, Fumiaki Aoki, Takehisa Shimizu, Hiroshi Doi, Keiko Kawai-Kowase, Tatsuya Iso, Tatsuo Suga, Masashi Arai, Masahiko Kurabayashi
American Journal of Respiratory Cell and Molecular Biology 2011, 45 (1): 136-44
Notch is an ancient cell-signaling system that regulates the specification of cell fate. This study examined the role of Notch in the epithelial-mesenchymal transition (EMT) and myofibroblast differentiation of cultured RLE-6TN cells (i.e., rat alveolar epithelial cells). The activation of Notch, either by ectopic expression of the Notch intracellular domain or by the co-culture of RLE-6TN cells with L-Jagged1 cells, induces the expression of smooth muscle α-actin (SMA) and other mesenchymal marker genes (collagen I and vimentin), and reduces the expression of epithelial marker genes (E-cadherin, occludin, and zonula occludens-1). The pharmacologic inhibition of the endogenous Notch signal significantly inhibited the transforming growth factor-β (TGF-β)-induced expression of SMA. Cell migratory capacity was increased by Notch. Luciferase assays revealed that the CC(A/T)(6)GG (CArG) box and the TGF-β control element (TCE) are required for Notch-induced SMA gene transcription. DNA microarray analysis revealed that members of the TGF-β family as well as Jagged1 were induced in RLE-6TN cells by Notch. Western blot analysis showed that Notch induced the phosphorylation of Smad3, and the TGF-β receptor type I/activin receptor-like kinase 5 (ALK5) kinase inhibitor SB431542 markedly reduced the Notch-induced expression of SMA. Enzyme-linked immunosorbent assays confirmed the production of TGF-β1 from RLE-6TN cells by Notch. Immunohistochemistry of a bleomycin-induced model of pulmonary fibrosis and lung specimens from patients with idiopathic interstitial pneumonias showed that Notch was strongly expressed in myofibroblasts, identified as SMA-positive cells. These data indicate that Notch induces myofibroblast differentiation through a TGF-β-Smad3 pathway that activates SMA gene transcription in a CArG-dependent and TCE-dependent manner in alveolar epithelial cells. Our data also imply that Notch induces the EMT phenotype, with increased migratory behavior in pulmonary fibrosis.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"