Publications [#80120] of Christopher D. Kontos

Papers Published

1. ES White, RG Atrasz, B Hu, SH Phan, V Stambolic, TW Mak, CM Hogaboam, KR Flaherty, FJ Martinez, CD Kontos, GB Toews, Negative regulation of myofibroblast differentiation by PTEN (Phosphatase and Tensin Homolog Deleted on chromosome 10)., American journal of respiratory and critical care medicine, vol. 173 no. 1 (January, 2006), pp. 112-21, ISSN 1073-449X [doi]
   (last updated on 2013/05/16)

   Abstract:
   BACKGROUND: Myofibroblasts are primary effector cells in idiopathic pulmonary fibrosis (IPF). Defining mechanisms of myofibroblast differentiation may be critical to the development of novel therapeutic agents. OBJECTIVE: To show that myofibroblast differentiation is regulated by phosphatase and tensin homolog deleted on chromosome 10 (PTEN) activity in vivo, and to identify a potential mechanism by which this occurs. METHODS: We used tissue sections of surgical lung biopsies from patients with IPF to localize expression of PTEN and alpha-smooth muscle actin (alpha-SMA). We used cell culture of pten(-/-) and wild-type fibroblasts, as well as adenoviral strategies and pharmacologic inhibitors, to determine the mechanism by which PTEN inhibits alpha-SMA, fibroblast proliferation, and collagen production. RESULTS: In human lung specimens of IPF, myofibroblasts within fibroblastic foci demonstrated diminished PTEN expression. Furthermore, inhibition of PTEN in mice worsened bleomycin-induced fibrosis. In pten(-/-) fibroblasts, and in normal fibroblasts in which PTEN was inhibited, alpha-SMA, proliferation, and collagen production was upregulated. Addition of transforming growth factor-beta to wild-type cells, but not pten(-/-) cells, resulted in increased alpha-SMA expression in a time-dependent fashion. In pten(-/-) cells, reconstitution of PTEN decreased alpha-SMA expression, proliferation, and collagen production, whereas overexpression of PTEN in wild-type cells inhibited transforming growth factor-beta-induced myofibroblast differentiation. It was observed that both the protein and lipid phosphatase actions of PTEN were capable of modulating the myofibroblast phenotype. CONCLUSIONS: The results indicate that in IPF, myofibroblasts have diminished PTEN expression. Inhibition of PTEN in vivo promotes fibrosis, and PTEN inhibits myofibroblast differentiation in vitro.

   Keywords:
   Actins • Animals • Antibiotics, Antineoplastic • Bleomycin • Cell Culture Techniques • Cell Differentiation • Fibroblasts • Fibrosis • Humans • Lung Diseases, Interstitial • Mice • Mice, Inbred C57BL • PTEN Phosphohydrolase • Pulmonary Fibrosis • Transforming Growth Factor beta • biosynthesis • chemically induced • genetics • pharmacokinetics • pharmacology • physiology • physiology* • physiopathology • physiopathology*