RATIONALE: Injury to alveolar epithelial cells (AECs) and to their repair process is integral to the pathogenesis of acute lung injury (ALI) and idiopathic pulmonary fibrosis (IPF). The mechanisms regulating the integrity of AECs and their intrinsic regulators remain unclear. Pten is a tumor suppressor, and its function in epithelial cells during organ fibrosis is unknown. OBJECTIVES: To determine the role of epithelial Pten in ALI and lung fibrosis. METHODS: Bronchioalveolar epithelium-specific Pten-deleted SP-C-rtTA/(tetO)(7)-Cre/Pten(Δ/Δ) (SOPten(Δ/Δ)) mice were studied by structural, biochemical, and physiologic analyses and compared with wild-type mice. Further mechanistic studies were performed in vivo, in vitro, and on samples from patients with IPF. MEASUREMENTS AND MAIN RESULTS: SOPten(Δ/Δ) mice demonstrated exacerbated alveolar flooding and subsequent augmented lung scarring with enhanced disassembly of tight junctions (TJs) of AECs and degradation of basement membranes. The induction of dominant negative PTEN gene in lung epithelial cells led to augmented transforming growth factor-1-induced disruptions of TJs. Epithelial-derived myofibroblasts were increased in the epithelium-specific Pten-deficient mice. The lungs of bleomycin-treated SOPten(Δ/Δ) mice showed increased pAkt, pS6K, Snail, and matrix metalloproteinase expressions and decreased claudin-4, E-cadherin, and laminin-β1 expressions. Akt inactivation definitively saved SOPten(Δ/Δ) mice through amelioration of ALI and retention of AEC integrity. We detected a reduction of PTEN expression and AKT hyperactivation in the AECs of human IPF lungs. CONCLUSIONS: Our results highlight epithelial Pten as a crucial gatekeeper controlling ALI and lung fibrosis by modulating AEC integrity, and the Pten/PI3K/Akt pathway as a potential therapeutic target in these intractable diseases.
RATIONALE: Injury to alveolar epithelial cells (AECs) and to their repair process is integral to the pathogenesis of acute lung injury (ALI) and idiopathic pulmonary fibrosis (IPF). The mechanisms regulating the integrity of AECs and their intrinsic regulators remain unclear. Pten is a tumor suppressor, and its function in epithelial cells during organ fibrosis is unknown. OBJECTIVES: To determine the role of epithelial Pten in ALI and lung fibrosis. METHODS: Bronchioalveolar epithelium-specific Pten-deleted SP-C-rtTA/(tetO)(7)-Cre/Pten(Δ/Δ) (SOPten(Δ/Δ)) mice were studied by structural, biochemical, and physiologic analyses and compared with wild-type mice. Further mechanistic studies were performed in vivo, in vitro, and on samples from patients with IPF. MEASUREMENTS AND MAIN RESULTS: SOPten(Δ/Δ) mice demonstrated exacerbated alveolar flooding and subsequent augmented lung scarring with enhanced disassembly of tight junctions (TJs) of AECs and degradation of basement membranes. The induction of dominant negative PTEN gene in lung epithelial cells led to augmented transforming growth factor-1-induced disruptions of TJs. Epithelial-derived myofibroblasts were increased in the epithelium-specific Pten-deficient mice. The lungs of bleomycin-treated SOPten(Δ/Δ) mice showed increased pAkt, pS6K, Snail, and matrix metalloproteinase expressions and decreased claudin-4, E-cadherin, and laminin-β1 expressions. Akt inactivation definitively saved SOPten(Δ/Δ) mice through amelioration of ALI and retention of AEC integrity. We detected a reduction of PTEN expression and AKT hyperactivation in the AECs of human IPF lungs. CONCLUSIONS: Our results highlight epithelial Pten as a crucial gatekeeper controlling ALI and lung fibrosis by modulating AEC integrity, and the Pten/PI3K/Akt pathway as a potential therapeutic target in these intractable diseases.
Authors: Robert D Guzy; Ivan Stoilov; Timothy J Elton; Robert P Mecham; David M Ornitz Journal: Am J Respir Cell Mol Biol Date: 2015-01 Impact factor: 6.914
Authors: Per Flodby; Janice M Liebler; Mitsuhiro Sunohara; Dan R Castillo; Alicia M McConnell; Manda S Krishnaveni; Agnes Banfalvi; Min Li; Barry Stripp; Beiyun Zhou; Edward D Crandall; Parviz Minoo; Zea Borok Journal: Am J Physiol Lung Cell Mol Physiol Date: 2016-11-18 Impact factor: 5.464
Authors: Marta Bueno; Yen-Chun Lai; Yair Romero; Judith Brands; Claudette M St Croix; Christelle Kamga; Catherine Corey; Jose D Herazo-Maya; John Sembrat; Janet S Lee; Steve R Duncan; Mauricio Rojas; Sruti Shiva; Charleen T Chu; Ana L Mora Journal: J Clin Invest Date: 2014-12-22 Impact factor: 14.808
Authors: Ashley R Rackow; David J Nagel; Claire McCarthy; Jennifer Judge; Shannon Lacy; Margaret A T Freeberg; Thomas H Thatcher; R Matthew Kottmann; Patricia J Sime Journal: Eur Respir J Date: 2020-11-26 Impact factor: 16.671
Authors: Emily A Vucic; Raj Chari; Kelsie L Thu; Ian M Wilson; Allison M Cotton; Jennifer Y Kennett; May Zhang; Kim M Lonergan; Katrina Steiling; Carolyn J Brown; Annette McWilliams; Keishi Ohtani; Marc E Lenburg; Don D Sin; Avrum Spira; Calum E Macaulay; Stephen Lam; Wan L Lam Journal: Am J Respir Cell Mol Biol Date: 2014-05 Impact factor: 6.914