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Query: UMLS:C0034069 (pulmonary fibrosis)
 7,050 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The incidence of apoptosis and the expression of Fas antigen (Fas)/Fas ligand (FasL) mRNA in bleomycin-induced pulmonary fibrosis in mice were examined. Male ICR mice were intratracheally instilled with bleomycin (5 U/kg of body weight). The controls were injected with sterile saline. The animals were anesthetized and killed at 1, 6, and 12 h, and 1, 3, 5, 7, 9, and 14 days after bleomycin instillation. We assessed the incidence of apoptosis in lung tissues by DNA fragmentation on agarose gel electrophoresis, terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end-labeling, and electron microscopy. The expression of Fas and FasL mRNA was detected by reverse transcription polymerase chain reaction (RT-PCR). The localization of Fas mRNA was analyzed by in situ hybridization and that of FasL mRNA was analyzed by RT in situ PCR. The results showed that (1) a single instillation of bleomycin leads to the rapid appearance of apoptosis in bronchial and alveolar epithelial cells, which resolves within 1 day, and (2) apoptosis reappears on day 7 and continues for over 14 days after bleomycin instillation. This was accompanied with a progression of fibrosis. Corticosteroid administration completely blocked both apoptosis and fibrosis. The expression of Fas mRNA was upregulated in the alveolar epithelial cells by the bleomycin instillation. FasL mRNA was also upregulated in infiltrating lymphocytes after bleomycin treatment, but not in the control mice. The administration of corticosteroids suppressed the expression of Fas and FasL mRNA as well as apoptosis and fibrosis. Although these results do not show that apoptosis mediated by the Fas/FasL system is directly linked to bleomycin-induced fibrosis, we speculate that excessive apoptosis and the Fas/FasL system play a role in the pathogenesis of bleomycin-induced lung injury.
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PMID:Apoptosis and expression of Fas/Fas ligand mRNA in bleomycin-induced pulmonary fibrosis in mice. 899 84

Fas antigen is a cell surface protein that mediates apoptosis, and it is expressed in various cells and tissues. Fas ligand binds to its receptor Fas, thus inducing apoptosis of Fas-bearing cells. Malfunction of the Fas-Fas ligand system causes lymphoproliferative disorders and autoimmune diseases, whereas its exacerbation may cause tissue destruction. We hypothesize that excessive apoptosis mediated by Fas-Fas ligand interaction may damage alveolar epithelial cells and result in pulmonary fibrosis. Mice were allowed to inhale repeatedly an aerosolized anti-Fas antibody for 14 days. The nuclei of bronchial and alveolar epithelial cells were positively stained by in situ DNA nick end labeling. Electron microscopy demonstrated apoptotic changes in bronchial and alveolar epithelial cells. Histologic findings and hydroxyproline content showed the development of pulmonary fibrosis, which was dependent on the dose of anti-Fas antibody. The repeated inhalation of control antibody (isotype-matched control hamster IgG) did not induce apoptosis of epithelial cells or pulmonary fibrosis. The expression of TGF-beta mRNA was upregulated from day 7 to day 28 in lung tissues of anti-Fas antibody-treated mice but not in those of control mice. In this report, we present the evidence that repeated inhalation of anti-Fas antibody mimicking Fas-Fas ligand crosslinking induces excessive apoptosis and inflammation, which results in pulmonary fibrosis in mice.
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PMID:Induction of apoptosis and pulmonary fibrosis in mice in response to ligation of Fas antigen. 930 12

Apoptosis serves important roles in organ development, cell differentiation, and the maintenance of homeostasis. Lung injury studies have underlined the role of fibroblast and endothelial cell apoptosis during lung repair from acute lung injuries, and demonstrated apoptosis of alveolar epithelial cells in association with diffuse alveolar damage. Pulmonary fibrosis is characterized by the loss of lung epithelial cells and the proliferation of fibroblasts. It is possible that p53, p21, Fas, Fas ligand, and other apoptosis-regulating proteins play an important role in the pathophysiology of lung injury and fibrosis.
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PMID:[The roles of apoptosis in lung injury and fibrosis]. 986 74

Pulmonary fibrosis begins with alveolitis, which progresses to destruction of lung tissue and excess collagen deposition. This process could be the result of DNA damage and a form of apoptosis. Therefore, we hypothesized that Fas ligand (FasL), which induces apoptosis in cells expressing Fas antigen (Fas), is associated with pulmonary fibrosis. We examined frozen lung tissues from seven patients with idiopathic pulmonary fibrosis (IPF), and bronchoalveolar lavage fluid (BALF) cells from 19 patients with IPF and from 17 patients with interstitial pneumonia associated with collagen vascular diseases (CVD-IP). We used five frozen lungs with normal lung parenchyma and BALF cells from 10 patients with solitary pulmonary nodule as controls. Reverse transcription-polymerase chain reaction (RT-PCR) showed that FasL messenger RNA (mRNA) was expressed in BALF cells from all patients with IPF and from 15 of 16 patients with CVD-IP. FasL mRNA was not detected in BALF cells except in one of 10 controls. RT in situ PCR detected FasL mRNA in inflammatory cells in BALF from patients with IPF. Immunohistochemistry detected FasL protein in infiltrating lymphocytes and granulocytes in all of seven frozen lung tissues of IPF, but in none of five control lung tissues. Additionally, the expression of Fas appeared to be upregulated in bronchiolar and alveolar epithelial cells in IPF compared with normal lung parenchyma by immunohistochemistry. We conclude that Fas and FasL were upregulated in fibrosing lung diseases and may associate with DNA damage or apoptosis of bronchiolar and alveolar epithelial cells in this disorder.
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PMID:The involvement of Fas-Fas ligand pathway in fibrosing lung diseases. 987 Sep 17

The Fas ligand is predominantly expressed in activated T lymphocytes and is one of the major effector molecules of cytotoxic T lymphocytes and natural killer cells. Previously, we found excessive apoptosis of epithelial cells and infiltrating lymphocytes expressing Fas ligand mRNA in the lung tissue of bleomycin-induced pulmonary fibrosis in mice. Here we demonstrated that the administration of a soluble form of Fas antigen or anti-Fas ligand antibody prevented the development of this model and that lpr and gld mice were resistant against the induction of pneumopathy. These results suggest that the Fas-Fas ligand pathway plays an essential role in the development of pulmonary fibrosis and that preventing this pathway could have therapeutic value in lung injury and fibrosis.
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PMID:Essential roles of the Fas-Fas ligand pathway in the development of pulmonary fibrosis. 1039 91

Epithelial cell injury is the common manifestation of lung injury. Contributing to such injury of epithelial cells is apoptosis. Although apoptosis is part of the normal process of epithelial renewal, in excess it is pathologic. We previously demonstrated the excessive apoptosis of lung epithelial cells and the upregulation of Fas and Fas ligand (FasL) in fibrosing lung diseases. We also showed that inhalation of anti-Fas antibody induced lung injury and fibrosis in mice. Interleukin (IL)-8 is one of the most important cytokines in the pathophysiology of acute lung injury and pulmonary fibrosis. In this study we investigated whether Fas ligation induces IL-8 secretion in addition to apoptosis in bronchiolar epithelial cells in vitro. Bronchiolar epithelial cells underwent apoptosis and also secreted IL-8 in response to tumor necrosis factor (TNF)-alpha or Fas ligation. New gene expression and protein synthesis were not necessary for Fas ligation- and TNF-alpha- mediated apoptosis, but were necessary for IL-8 secretion. We further found that Fas ligation induced activation of nuclear factor-kappa B. We conclude that the Fas/FasL pathway not only mediates apoptosis but also plays a proinflammatory role, and that stimulation of the Fas/FasL pathway in bronchiolar epithelial cells leads to IL-8 production, which may amplify the inflammatory cascade in lung injury and pulmonary fibrosis.
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PMID:Induction of interleukin-8 secretion and apoptosis in bronchiolar epithelial cells by Fas ligation. 1046 Jul 62

Up-regulation of Fas and Fas ligand and excessive apoptosis of bronchiolar and alveolar epithelial cells were identified in bleomycin-induced pulmonary fibrosis in mice. This study hypothesized that apoptosis-regulatory genes other than Fas-Fas ligand, such as p53, p21 (Waf1/Cip1), bcl-2, bcl-x, and bax, may also participate in epithelial cell apoptosis in this model. The expression of these genes was assessed by reverse transcription polymerase chain reaction (RT-PCR), RT in situ PCR, or immunohistochemistry. The expression of p53 and p21 mRNA was concurrently up-regulated in the alveolar epithelial cells at 1 h to 7 days after intratracheal instillation of bleomycin. The expression of bcl-2 mRNA was weakly up-regulated at 1 h to 14 days, while the expression level of bcl-2 protein was not changed. The expression of bcl-x(L) and bax mRNA was strongly up-regulated at 1 h to 7 days. The expression of bcl-x protein was up-regulated in lymphocytes and macrophages, whereas bax protein was up-regulated in both epithelial and inflammatory cells. It is concluded that epithelial cell apoptosis in this model may also be induced by the up-regulation of p53 and bax and by the imbalance between apoptosis-inducible and -inhibitory genes, in addition to the up-regulation of the Fas-Fas ligand pathway.
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PMID:Expression of apoptosis-regulatory genes in epithelial cells in pulmonary fibrosis in mice. 1065 22

Caspases have been implicated in the effector process of apoptosis in several systems including the Fas-Fas ligand pathway. We previously demonstrated that excessive apoptosis of lung epithelial cells and the Fas-Fas ligand pathway were essential in the pathogenesis of bleomycin-induced pneumopathy in mice. Therefore, the purpose of this study was to investigate whether a caspase inhibitor could prevent the development of this model. The expression of caspase-1 and caspase-3 was upregulated on lung epithelial cells, alveolar macrophages, and infiltrating inflammatory cells in this model. We demonstrated that a broad-spectrum caspase inhibitor, N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, decreased the caspase-1- and caspase-3-like activity, the number of apoptotic cells, the pathological grade of lung inflammation and fibrosis, and the hydroxyproline content in lung tissues in this model. We conclude that caspase inhibitors could be a new therapeutic approach against lung injury and pulmonary fibrosis.
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PMID:Attenuation of bleomycin-induced pneumopathy in mice by a caspase inhibitor. 1115 11

We previously demonstrated essential roles of the Fas-Fas ligand (FasL) pathway in bleomycin-induced pneumopathy in mice. T lymphocytes and natural killer cells express FasL on activation and use it as a cytotoxic effector molecule. Because interleukin (IL)-12 is known to play a critical role in cell-mediated immunity, we investigated whether anti-IL-12 antibody treatment suppresses the development of this model. The anti-IL-12 antibody treatment decreased the number of apoptotic cells and the degree of inflammation and fibrosis in lung tissue. The results of RT-PCR showed that IL-12p40, IL-12 receptor (R) beta2, interferon-gamma, tumor necrosis factor-alpha and FasL mRNAs were upregulated after bleomycin instillation. The upregulation of FasL, IL-12Rbeta2, and tumor necrosis factor-alpha mRNA expression in lung tissue was suppressed by anti-IL-12 antibody treatment. The results of enzyme-linked immunosorbent assay showed that the levels of IL-12p40, but not of IL-12p70, were increased in lung tissue after bleomycin instillation. Although the increase in IL-12Rbeta2 mRNA levels suggests that the T helper type 1 cell response may participate in lung injury, the increase in IL-12p40 supports T helper type 2 cell predominance in the fibrotic process of this model. The administration of anti-IL-12 antibody could be a novel therapy against lung injury and pulmonary fibrosis.
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PMID:Attenuation of bleomycin-induced pneumopathy in mice by monoclonal antibody to interleukin-12. 1135 Jul 91

The Fas/Fas ligand (FasL) system has been implicated in alveolar epithelial cell apoptosis during pulmonary fibrosis and acute respiratory distress syndrome. However, Fas ligation can also lead to cell activation and cytokine production. The goal of this study was to determine the role of the Fas/FasL system in host defenses against Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. We administered bacteria by aerosolization into the lungs of Fas-deficient (lpr) mice and wild-type (C57BL/6) mice and measured bacterial clearance at 6 and 12 h. One hour prior to euthanasia, the mice received an intraperitoneal injection of human serum albumin (HSA) for alveolar permeability determinations. At all times after bacterial challenges, the lungs of the lpr mice contained similar or lower numbers of bacteria than those of the C57BL/6 mice. Alveolar permeability changes, as determined by bronchoalveolar lavage fluid HSA concentrations, were less severe in the lpr mice 6 h after the challenges. In response to E. coli, the lpr mice had significantly more polymorphonuclear leukocytes (PMN) and macrophage inflammatory protein 2 in the lungs, whereas histopathologic changes were less severe. In contrast, in response to the gram-positive cocci, the lpr animals had similar or lower numbers of PMN. We conclude that the Fas/FasL system contributes to the development of permeability changes and tissue injury during-gram negative bacterial pneumonia. The Fas/FasL system did not have a major role in the clearance of aerosolized bacteria from the lungs at the bacterial doses tested.
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PMID:Fas/Fas ligand system mediates epithelial injury, but not pulmonary host defenses, in response to inhaled bacteria. 1150 Apr 54


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