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Cellular and Molecular Biology Letters

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Volume 12, Issue 3


The effect of TGF-β1 and Smad7 gene transfer on the phenotypic changes of rat alveolar epithelial cells

Guo-Ping Xu / Qing-Quan Li / Xi-Xi Cao / Qi Chen / Zhong-Hua Zhao / Zi-Qiang Diao / Zu-De Xu
Published Online: 2007-04-25 | DOI: https://doi.org/10.2478/s11658-007-0018-x


The aim of this study was to investigate whether transforming growth factor-β1 (TGF-β1) could induce alveolar epithelial-mesenchymal transition (EMT) in vitro, and whether Smad7 gene transfer could block this transition. We also aimed to elucidate the possible mechanisms of these processes. The Smad7 gene was transfected to the rat type II alveolar epithelial cell line (RLE-6TN). Expression of the EMT-associated markers was assayed by Western Blot and Real-time PCR. Morphological alterations were examined via phase-contrast microscope and fluorescence microscope, while ultrastructural changes were examined via electron microscope. TGF-β1 treatment induced a fibrotic phenotype of RLE-6TN with increased expression of fibronectin (FN), α-smooth muscle actin (α-SMA) and vimentin, and decreased expression of E-cadherin (E-cad) and cytokeratin19 (CK19). After transfecting the RLE-6TN with the Smad7 gene, the expression of the mesenchymal markers was downregulated while that of the epithelial markers was upregulated. TGF-β1 treatment for 48 h resulted in the separation of RLE-6TN from one another and a change into elongated, myofibroblast-like cells. After the RLE-6TN had been transfected with the Smad7 gene, TGF-β1 treatment had no effect on the morphology of the RLE-6TN. TGF-β1 treatment for 48 h resulted in an abundant expression of α-SMA in the RLE-6TN. If the RLE-6TN were transfected with the Smad7 gene, TGF-β1 treatment for 48 h could only induce a low level of α-SMA expression. Furthermore, TGF-β1 treatment for 12 h resulted in the degeneration and swelling of the osmiophilic multilamellar bodies, which were the markers of type II alveolar epithelial cells. TGF-β1 can induce alveolar epithelialmesenchymal transition in vitro, which is dependent on the Smads signaling pathway to a certain extent. Overexpression of the Smad7 gene can partially block this process

Keywords: Epithelial-mesenchymal transition; Gene transfer; Smad7; Transforming growth factor-β1

  • [1] Selman, M., King, T.E. and Pardo, A. Idiopathic pulmonary fibrosis: prevailing and evolving hypotheses about its pathogenesis and implications for therapy. Ann. Intern. Med. 134 (2001) 136–151. Google Scholar

  • [2] King, T.E., Schwarz, M.I., Brown, K., Tooze, J.A., Colby, T.V., Waldron, J.A., Flint, A., Thurlbeck, W. and Cherniack, R.M. Idiopathic pulmonary fibrosis: relationship between histopathologic features and mortality. Am. J. Respir. Crit. Care Med. 164 (2001) 1025–1032. Google Scholar

  • [3] Selman, M. and Pardo, A. Idiopathic pulmonary fibrosis: an epithelial/fibroblastic cross-talk disorder. Respir Res. 3 (2002) 3. http://dx.doi.org/10.1186/rr175CrossrefGoogle Scholar

  • [4] Yao, H.W., Xie, Q.M., Chen, J.Q., Deng, Y.M. and Tang, H.F. TGF-beta 1 induces alveolar epithelial to mesenchymal cell transition in vitro. Life Sci. 76 (2004) 29–37. http://dx.doi.org/10.1016/j.lfs.2004.06.019Web of ScienceGoogle Scholar

  • [5] Gauldie, J., Kolb, M. and Sime, P.J. A new direction in the pathogenesis of idiopathic pulmonary fibrosis? Respir Res. 3 (2002) 1. http://dx.doi.org/10.1186/rr158CrossrefGoogle Scholar

  • [6] Kalluri, R. and Neilson, E.G. Epithelial-mesenchymal transition and its implications for fibrosis. J. Clin. Invest. 112 (2003) 1776–1784. http://dx.doi.org/10.1172/JCI200320530CrossrefGoogle Scholar

  • [7] Liu, Y. Epithelial to mesenchymal transition in renal fibrogenesis: athologic significance, molecular mechanism, and therapeutic intervention. J. Am. Soc. Nephrol. 15 (2004) 1–12. http://dx.doi.org/10.1097/01.ASN.0000106015.29070.E7CrossrefGoogle Scholar

  • [8] Desmouliere, A., Darby, I.A. and Gabbiani, G. Normal and pathologic soft tissue remodeling: role of the myofibroblast, with special emphasis on liver and kidney fibrosis. Lab. Invest. 83 (2003) 1689–1707. http://dx.doi.org/10.1097/01.LAB.0000101911.53973.90CrossrefGoogle Scholar

  • [9] Moustakas, A., Pardali, K. and Gaal, A. Mechanisms of TGF-b signaling in regulation of cell growth and differentiation. Immunol. Lett. 82 (2002) 85–91. http://dx.doi.org/10.1016/S0165-2478(02)00023-8CrossrefGoogle Scholar

  • [10] Desmouliere, A. Factors influencing myofibroblast differentiation during wound healing and fibrosis. Cell Biol. Int. 19 (1995) 471–476. http://dx.doi.org/10.1006/cbir.1995.1090CrossrefGoogle Scholar

  • [11] ten Dijke, P., Goumans, M.J., Itoh, F. and Itoh, S. Regulation of cell proliferation by Smad proteins. J. Cell Physiol. 191 (2002) 1–16. http://dx.doi.org/10.1002/jcp.10066CrossrefGoogle Scholar

  • [12] Massague, J. and Wotton, D. Transcriptional control by the TGF-b/Smad signaling system. EMBO J. 19 (2000) 1745–1754. http://dx.doi.org/10.1093/emboj/19.8.1745CrossrefGoogle Scholar

  • [13] Derynck, R. and Zhang, Y.E. Smad-dependent and Smad-independent pathways in TGF-b family signaling. Nature 425 (2003) 577–584. http://dx.doi.org/10.1038/nature02006CrossrefGoogle Scholar

  • [14] Lan, H.Y., Mu, W., Tomita, N., Huang, X.R., Li, J.H. and Zhu, H.J. Inhibition of renal fibrosis by gene transfer of inducible Smad7 using Ultrasound-microbubble system in rat UUO model. J. Am. Soc. Nephrol. 14 (2003) 1535–1548. http://dx.doi.org/10.1097/01.ASN.0000067632.04658.B8CrossrefGoogle Scholar

  • [15] Dooley, S., Hamzavi, J., Breitkopf, K., Wiercinska, E., Said, H.M., Lorenzen, J., ten Dijke, P. and Gressner, A.M. Smad7 prevents activation of hepatic stellate cells and liver fibrosis in rats. Gastroenterology 125 (2003) 178–191. http://dx.doi.org/10.1016/S0016-5085(03)00666-8CrossrefGoogle Scholar

  • [16] Zavadil, J. and Bottinger, E.P. TGF-beta and epithelial-to-mesenchymal transitions. Oncogene 24 (2005) 5764–5774. http://dx.doi.org/10.1038/sj.onc.1208927CrossrefGoogle Scholar

  • [17] Greenburg, G. and Hay, E.D. Epithelia suspended in collagen gels can lose polarity and express characteristics of migrating mesenchymal cells. J. Cell Biol. 95 (1982) 333–339. http://dx.doi.org/10.1083/jcb.95.1.333CrossrefGoogle Scholar

  • [18] Stoker, M. and Perryman, M. An epithelial scatter factor released by embryo fibroblasts. J. Cell Sci. 77 (1985) 209–23. Google Scholar

  • [19] Miettinen, P.J., Ebner, R., Lopez, A.R. and Derynck, R. TGF-beta induced transdifferentiation of mammary epithelial cells to mesenchymal cells: involvement of type I receptors. J. Cell Biol. 127 (1994) 2021–2036. http://dx.doi.org/10.1083/jcb.127.6.2021CrossrefGoogle Scholar

  • [20] Kalluri, R. and Neilson, E.G. Epithelial-mesenchymal transition and its implications for fibrosis. J. Clin. Invest. 112 (2003) 1776–1784. http://dx.doi.org/10.1172/JCI200320530CrossrefGoogle Scholar

  • [21] Saika, S., Kono-Saika, S., Tanaka, T., Yamanaka, O., Ohnishi, Y., Sato, M., Muragaki, Y., Ooshima, A., Yoo, J., Flanders, K.C. and Roberts, A.B. Smad3 is required for dedifferentiation of retinal pigment epithelium following retinal detachment in mice. Lab. Invest. 84 (2004) 1245–1258. http://dx.doi.org/10.1038/labinvest.3700156CrossrefGoogle Scholar

  • [22] Valcourt, U., Kowanetz, M., Niimi, H., Valcourt U., Heldin, C.H. and Moustakas, A. TGF-beta and the Smad signaling pathway support transcriptomic reprogramming during epithelial-mesenchymal cell transition. Mol. Biol. Cell. 16 (2005) 1987–2002. http://dx.doi.org/10.1091/mbc.E04-08-0658CrossrefGoogle Scholar

  • [23] Lan, H.Y., Mu, W., Tomita, N., Huang, X.R., Li, J.H., Zhu, H.J., Morishita, R. and Johnson, R.J. Inhibition of renal fibrosis by gene transfer of inducible Smad7 using ultrasound-microbubble system in rat UUO model. J. Am. Soc. Nephrol. 14 (2003) 1535–1548. http://dx.doi.org/10.1097/01.ASN.0000067632.04658.B8CrossrefGoogle Scholar

About the article

Published Online: 2007-04-25

Published in Print: 2007-09-01

Citation Information: Cellular and Molecular Biology Letters, Volume 12, Issue 3, Pages 457–472, ISSN (Online) 1689-1392, DOI: https://doi.org/10.2478/s11658-007-0018-x.

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© 2007 University of Wrocław, Poland. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License. BY-NC-ND 3.0

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