Role of type II pneumocyte senescence in radiation-induced lung fibrosis.

BACKGROUND Radiation is a commonly delivered therapeutic modality for cancer. The causes underlying the chronic, progressive nature of radiation injury in the lung are poorly understood. METHODS C57Bl/6NCr mice were exposed to thoracic irradiation (n = 3 per dose and time point for tissue collection). Microarray analysis of gene expression from irradiated murine lung was performed using one-way analysis of variance with post hoc Scheffe analysis. Senescence and type II airway epithelial cell (AECII) count were assayed in irradiated murine lung tissue (n = 3 per condition). Irradiated mice were treated with diphenyleneiodonium (DPI), an inhibitor of NADPH oxidase (NOX), and fibrosis was assessed by collagen assays. All statistical tests were two-tailed. RESULTS Gene expression in lung tissue from mice irradiated to 17.5 Gy clustered with that of aged unirradiated mice. Only fibrogenic exposures led to AECII senescence (0 Gy: 0.66% ± 0.67%; 5 Gy: 4.5% ± 1.19%; 17.5 Gy: 18.7% ± 3.05; P = .007) and depletion (0 Gy: 2.89 per alveolus ± 0.26; 5 Gy: 2.41 ± 0.19; 17.5 Gy: 1.6 ± 0.14; P < .001) at 30 weeks. Treatment of irradiated mice with DPI for 16 weeks markedly reduced collagen accumulation (5×6 Gy: 57.26 μg/lung ± 9.91; 5×6 Gy ± DPI: 36.54μg/lung ± 4.39; P = .03) and AECII senescence (5×6 Gy: 37.61% ± 4.82%; 5×6 Gy ± DPI: 12.38% ± 2.78; P < .001). CONCLUSIONS These studies identify senescence as an important process in AECII in vivo and indicate that NOX is a critical mediator of radiation-induced AECII senescence and pulmonary fibrosis.

[1]  J. Ciezki,et al.  PARP Inhibition Sensitizes to Low Dose-Rate Radiation TMPRSS2-ERG Fusion Gene-Expressing and PTEN-Deficient Prostate Cancer Cells , 2013, PloS one.

[2]  M. Olszewski,et al.  Implicating Exudate Macrophages and Ly-6Chigh Monocytes in CCR2-Dependent Lung Fibrosis following Gene-Targeted Alveolar Injury , 2013, The Journal of Immunology.

[3]  Weiling Zhao,et al.  The Role of Alveolar Epithelium in Radiation-Induced Lung Injury , 2013, PloS one.

[4]  V. Thannickal,et al.  Caveolin-1 deficiency protects from pulmonary fibrosis by modulating epithelial cell senescence in mice. , 2012, American journal of respiratory cell and molecular biology.

[5]  Takashi Nakano,et al.  Garcinol, a histone acetyltransferase inhibitor, radiosensitizes cancer cells by inhibiting non-homologous end joining. , 2012, International journal of radiation oncology, biology, physics.

[6]  Isabel L Jackson,et al.  Oxidative stress mediates radiation lung injury by inducing apoptosis. , 2012, International journal of radiation oncology, biology, physics.

[7]  K. Ang,et al.  TP53 Disruptive Mutations Lead to Head and Neck Cancer Treatment Failure through Inhibition of Radiation-Induced Senescence , 2011, Clinical Cancer Research.

[8]  B. Hinz,et al.  A key role for NOX4 in epithelial cell death during development of lung fibrosis. , 2011, Antioxidants & redox signaling.

[9]  K. Kuwano,et al.  Accelerated epithelial cell senescence in IPF and the inhibitory role of SIRT6 in TGF-β-induced senescence of human bronchial epithelial cells. , 2011, American journal of physiology. Lung cellular and molecular physiology.

[10]  M. Plotkin,et al.  INK4a knockout mice exhibit increased fibrosis under normal conditions and in response to unilateral ureteral obstruction. , 2010, American journal of physiology. Renal physiology.

[11]  Alan Bilsland,et al.  Scoring of senescence signalling in multiple human tumour gene expression datasets, identification of a correlation between senescence score and drug toxicity in the NCI60 panel and a pro-inflammatory signature correlating with survival advantage in peritoneal mesothelioma , 2010, BMC Genomics.

[12]  M. Anscher,et al.  Radiation pulmonary toxicity: from mechanisms to management. , 2010, Seminars in radiation oncology.

[13]  E. White,et al.  Targeted injury of type II alveolar epithelial cells induces pulmonary fibrosis. , 2010, American journal of respiratory and critical care medicine.

[14]  Judith Campisi,et al.  Senescence-Associated Secretory Phenotypes Reveal Cell-Nonautonomous Functions of Oncogenic RAS and the p53 Tumor Suppressor , 2008, PLoS biology.

[15]  D. Peeper,et al.  Oncogene-Induced Senescence Relayed by an Interleukin-Dependent Inflammatory Network , 2008, Cell.

[16]  T. Finkel,et al.  Free radicals and senescence. , 2008, Experimental cell research.

[17]  A. Owen,et al.  AGEMAP: A Gene Expression Database for Aging in Mice , 2007, PLoS genetics.

[18]  Weiling Zhao,et al.  Oxidative damage pathways in relation to normal tissue injury. , 2007, The British journal of radiology.

[19]  W. M. Foster,et al.  Temporal onset of hypoxia and oxidative stress after pulmonary irradiation. , 2007, International journal of radiation oncology, biology, physics.

[20]  Chao Xing,et al.  Adult-onset pulmonary fibrosis caused by mutations in telomerase , 2007, Proceedings of the National Academy of Sciences.

[21]  P. Lansdorp,et al.  Telomerase mutations in families with idiopathic pulmonary fibrosis. , 2007, The New England journal of medicine.

[22]  John S. Van Arnam,et al.  Threshold of Lung Injury Required for the Appearance of Marrow‐Derived Lung Epithelia , 2006, Stem cells.

[23]  M. Selman,et al.  Role of epithelial cells in idiopathic pulmonary fibrosis: from innocent targets to serial killers. , 2006, Proceedings of the American Thoracic Society.

[24]  R. Colavitti,et al.  Reactive Oxygen Species as Mediators of Cellular Senescence , 2005, IUBMB life.

[25]  T. Samulski,et al.  The protective effect of recombinant human keratinocyte growth factor on radiation-induced pulmonary toxicity in rats. , 2004, International journal of radiation oncology, biology, physics.

[26]  D. Warburton,et al.  Isolation of a putative progenitor subpopulation of alveolar epithelial type 2 cells. , 2004, American journal of physiology. Lung cellular and molecular physiology.

[27]  K. Trott,et al.  Target cells in radiation pneumopathy. , 2004, International journal of radiation oncology, biology, physics.

[28]  T. Tsuji,et al.  Bleomycin induces cellular senescence in alveolar epithelial cells , 2003, European Respiratory Journal.

[29]  R. Kairalla,et al.  Evidence of type II pneumocyte apoptosis in the pathogenesis of idiopathic pulmonary fibrosis (IFP)/usual interstitial pneumonia (UIP) , 2001, Journal of clinical pathology.

[30]  Q. Chen,et al.  Apoptosis or senescence-like growth arrest: influence of cell-cycle position, p53, p21 and bax in H2O2 response of normal human fibroblasts. , 2000, The Biochemical journal.

[31]  S. Nagata,et al.  Essential roles of the Fas-Fas ligand pathway in the development of pulmonary fibrosis. , 1999, The Journal of clinical investigation.

[32]  B. Ames,et al.  Molecular analysis of H2O2-induced senescent-like growth arrest in normal human fibroblasts: p53 and Rb control G1 arrest but not cell replication. , 1998, The Biochemical journal.

[33]  G. Saretzki,et al.  Mild hyperoxia shortens telomeres and inhibits proliferation of fibroblasts: a model for senescence? , 1995, Experimental cell research.

[34]  B. Ames,et al.  Senescence-like growth arrest induced by hydrogen peroxide in human diploid fibroblast F65 cells. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[35]  R. J. Stephens,et al.  Transformation of alveolar type 2 cells to type 1 cells following exposure to NO2. , 1975, Experimental and molecular pathology.

[36]  R Core Team,et al.  R: A language and environment for statistical computing. , 2014 .

[37]  R. Mirzayans,et al.  Induction of Accelerated Senescence by γ Radiation in Human Solid Tumor-Derived Cell Lines Expressing Wild-Type TP53 , 2005, Radiation research.

[38]  Alex E. Lash,et al.  Gene Expression Omnibus: NCBI gene expression and hybridization array data repository , 2002, Nucleic Acids Res..

[39]  J. Vávrová,et al.  The alveolar septal thickness and type II pneumocytes number in irradiated lungs, time expression and the effect of pentoxifylline. , 2001, Acta medica.

[40]  N. Willich,et al.  Dose-dependent induction of transforming growth factor beta (TGF-beta) in the lung tissue of fibrosis-prone mice after thoracic irradiation. , 2000, International journal of radiation oncology, biology, physics.

[41]  N. Willich,et al.  Dose-dependent induction of transforming growth factor β (TGF-β) in the lung tissue of fibrosis-prone mice after thoracic irradiation , 1999 .

[42]  E. Weibel,et al.  Pathogenesis and reversibility of the pulmonary lesions of oxygen toxicity in monkeys. II. Ultrastructural and morphometric studies. , 1969, Laboratory investigation; a journal of technical methods and pathology.