QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Vol. 20, Issue 22, 4751-4765, November 15, 2009

This Article Full Text Full Text (PDF) All Versions of this Article: E09-01-0019v1 20/22/4751    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kolosionek, E. Articles by Pullamsetti, S. S. Search for Related Content PubMed PubMed Citation Articles by Kolosionek, E. Articles by Pullamsetti, S. S.

Expression and Activity of Phosphodiesterase Isoforms during Epithelial Mesenchymal Transition: The Role of Phosphodiesterase 4

Ewa Kolosionek^*, Rajkumar Savai, Hossein Ardeschir Ghofrani^*, Norbert Weissmann^*, Andreas Guenther^*, Friedrich Grimminger^*,, Werner Seeger^*,, Gamal Andre Banat, Ralph Theo Schermuly^*,, and Soni Savai Pullamsetti^*,

Department of Hematology and Oncology, *University of Giessen Lung Centre, Giessen, Germany; and Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany

Submitted January 7, 2009; Revised August 10, 2009; Accepted September 10, 2009
Monitoring Editor: Keith E. Mostov

Epithelial–mesenchymal transition (EMT) has emerged as a critical event in the pathogenesis of organ fibrosis and cancer and is typically induced by the multifunctional cytokine transforming growth factor (TGF)-β1. The present study was undertaken to evaluate the potential role of phosphodiesterases (PDEs) in TGF-β1-induced EMT in the human alveolar epithelial type II cell line A549. Stimulation of A549 with TGF-β1 induced EMT by morphological alterations and by expression changes of the epithelial phenotype markers E-cadherin, cytokeratin-18, zona occludens-1, and the mesenchymal phenotype markers, collagen I, fibronectin, and -smooth muscle actin. Interestingly, TGF-β1 stimulation caused twofold increase in total cAMP-PDE activity, contributed mostly by PDE4. Furthermore, mRNA and protein expression demonstrated up-regulation of PDE4A and PDE4D isoforms in TGF-β1-stimulated cells. Most importantly, treatment of TGF-β1 stimulated epithelial cells with the PDE4-selective inhibitor rolipram or PDE4 small interfering RNA potently inhibited EMT changes in a Smad-independent manner by decreasing reactive oxygen species, p38, and extracellular signal-regulated kinase phosphorylation. In contrast, the ectopic overexpression of PDE4A and/or PDE4D resulted in a significant loss of epithelial marker E-cadherin but did not result in changes of mesenchymal markers. In addition, Rho kinase signaling activated by TGF-β1 during EMT demonstrated to be a positive regulator of PDE4. Collectively, the findings presented herein suggest that TGF-β1 mediated up-regulation of PDE4 promotes EMT in alveolar epithelial cells. Thus, targeting PDE4 isoforms may be a novel approach to attenuate EMT-associated lung diseases such as pulmonary fibrosis and lung cancer.

Address correspondence to: Ralph Theo Schermuly (ralph.schermuly{at}mpi-bn.mpg.de)

Abbreviations used: Epithelial-to-Mesenchymal Transition, (EMT); Transforming Growth Factor-β1, (TGF-β1); Phosphodiesterases, (PDE); Reactive Oxygen Species, (ROS).