Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0034069 (pulmonary fibrosis)
 7,050 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Integrin activation promotes the survival of endothelial cells undergoing diverse forms of stress. Here we determined the ability of integrins to inhibit DNA strand breakage by bleomycin (BLM), a DNA-cleaving antitumor antibiotic that causes acute endothelial injury and subsequent pulmonary fibrosis. We found that BLM produced DNA breakage in cultured murine lung endothelial cells (MLEC) within 45 min of treatment as measured by DNA sedimentation and in situ labeling of 3'-OH by nick translation (ISNT). Two hours after the removal of BLM, we found a marked but incomplete reduction in DNA strand breakage as measured by ISNT, indicating that the damage was reversible. DNA sedimentation and ISNT demonstrated that strand breakage due to BLM was inhibited in MLEC cultured on fibronectin, and no evidence of breakage was found 2 h after removal of the drug in ISNT experiments. Gelatin, type IV collagen, laminin, and the integrin ligand peptide Gly-Arg-Gly-Asp-Ser-Pro, but not the inactive Gly-Arg-Ala-Asp-Ser-Pro peptide, also inhibited DNA strand breakage. Activation of integrins, either by coating surfaces with antibodies to alpha 5-, beta 1-, or beta 3-integrin subunits or by receptor clustering with the soluble antibodies, inhibited BLM-induced DNA breakage. Inhibition of BLM-induced DNA strand breakage by soluble beta 1-integrin antibody increased with increasing antibody concentration and duration of receptor clustering before BLM treatment. Thus integrin activation protects pulmonary endothelial cells from the genotoxic effects of BLM.
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PMID:Integrin activation protects pulmonary endothelial cells from the genotoxic effects of bleomycin. 931 96

Matrix metalloproteinases (MMPs) have been implicated in the pathological processes of interstitial lung diseases. However, underlying mechanisms, particularly for activity levels and distribution of activated MMP-2 in the disease process, are yet to be elucidated. The present study investigated the immunolocalization of MMP-2, membrane type 1-matrix metalloproteinase (MT1-MMP), tissue inhibitor of metalloproteinase (TIMP)-2, p53, and Ki-67 in a rabbit model of bleomycin-induced pulmonary fibrosis. Gelatin zymography and in situ zymography were used to examine the activity and the localization of MMP-2. Furthermore, we performed Western blot and in situ hybridization for MT1-MMP, an activator for MMP-2. The total MMP-2 level estimated by gelatin zymography increased significantly at 3, 7, and 14 days after bleomycin administration, compared with controls. In the immunohistochemical study, immunoreaction for MMP-2 was strongest in alveolar epithelial cells among the cell populations. Swollen and/or elongated type II alveolar epithelial cells showed strong immunoreactions for MMP-2, MT1-MMP, and TIMP-2. After bleomycin administration, immunoreaction for p53 was observed in bronchiolar and alveolar epithelial cells. The proportion of p53-positive cells was high in epithelial cells from 1 to 14 days as MMP-2 levels were increased, suggesting that p53 may be responsible, at least in part, for the increase of MMP-2. The ratio of activated MMP-2 to total MMP-2 estimated by gelatin zymography increased significantly at 3, 7, 14, and 28 days after bleomycin treatment. In situ zymography revealed that type II alveolar epithelial cells degraded gelatin. An increased expression of MT1-MMP protein was observed by Western blot following administration of bleomycin. In situ hybridization demonstrated that type II alveolar epithelial cells gave intense signal for MT1-MMP mRNA. These results suggest that type II alveolar epithelial cells express MT1-MMP and activate MMP-2 on their cell surfaces, which may lead to the elongation and migration of alveolar epithelial cells in the repair process of bleomycin-induced pulmonary fibrosis.
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PMID:Role of MMP-2 in alveolar epithelial cell repair after bleomycin administration in rabbits. 1155 78

Macrophage infiltration is implicated in various types of pulmonary fibrosis. One important pathogenetic process associated with pulmonary fibrosis is injury to basement membranes by matrix metalloproteinases (MMPs) that are produced mainly by macrophages. In this study, C-C chemokine receptor 2-deficient (CCR2-/-) mice were used to explore the relationship between macrophage infiltration and MMP activity in the pathogenesis of pulmonary fibrosis, using the bleomycin-induced model of this disease process. CCR2 is the main (if not only) receptor for monocyte chemoattractant protein-1/C-C chemokine ligand 2 (MCP-1/CCL2), which is a critical mediator of macrophage trafficking, and CCR2 -/- mice demonstrate defective macrophage migration. Pulmonary fibrosis was induced in CCR2-/- and wild-type (CCR2+/+) mice by intratracheal instillation of bleomycin. No significant differences in the total protein concentration in bronchoalveolar lavage (BAL) fluid, or in the degree of histological lung inflammation, were observed in the two groups until day 7. Between days 3 and 21, however, BAL fluid from CCR2-/- mice contained fewer macrophages than BAL fluid from CCR2+/+ mice. Gelatin zymography of BAL fluid and in situ zymography revealed reduced gelatinolytic activity in CCR2-/- mice. Immunocytochemical staining showed weaker expression of MMP-2 and MMP-9 in macrophages in BAL fluid from CCR2-/- mice at day 3. Gelatin zymography of protein extracted from alveolar macrophages showed reduced gelatinolytic activity of MMP-2 and MMP-9 in CCR2-/- mice. At days 14 and 21, lung remodelling and the hydroxyproline content of lung tissues were significantly reduced in CCR2-/- mice. These results suggest that the CCL2/CCR2 functional pathway is involved in the pathogenesis of bleomycin-induced pulmonary fibrosis and that CCR2 deficiency may improve the outcome of this disease by regulating macrophage infiltration and macrophage-derived MMP-2 and MMP-9 production.
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PMID:C-C chemokine receptor 2 (CCR2) deficiency improves bleomycin-induced pulmonary fibrosis by attenuation of both macrophage infiltration and production of macrophage-derived matrix metalloproteinases. 1553 37

Inhalation of asbestos fibers causes pulmonary inflammation and eventual pulmonary fibrosis (asbestosis). Although the underlying molecular events are poorly understood, protease/antiprotease and oxidant/antioxidant imbalances are believed to contribute to the disease. Implicated in other forms of pulmonary fibrosis, the matrix metalloproteinases (MMPs) have not been examined in asbestosis. We therefore hypothesized that MMPs play a pathogenic role in asbestosis development. Wild-type C57BL/6 mice were intratracheally instilled with 0.1 mg crocidolite asbestos, causing an inflammatory response at 1 d and a developing fibrotic response at 7, 14, and 28 d. Gelatin zymography demonstrated an increase in MMP-9 (gelatinase B) during the inflammatory phase, while MMP-2 (gelatinase A) was profoundly increased in the fibrotic phase. Immunohistochemistry revealed MMP-9 in and around bronchiolar and airspace neutrophils that were often associated with visible asbestos fibers. MMP-2 was found in fibrotic regions at 7, 14, and 28 d. No increases in RNA levels of MMP-2, MMP-9, or MMP-8 were found, but levels of MMP-7, MMP-12, and MMP-13 RNA did increase at 14 d. The MMP inhibitors, TIMP-1 and TIMP-2, were also increased at 7-28 d after asbestos exposure. To confirm the importance of MMP activity in disease progression, mice exposed to asbestos were given daily injections of the MMP inhibitor, GM6001. MMP inhibition reduced inflammation and fibrosis in asbestos-treated mice. Collectively, these data suggest that MMPs contribute to the pathogenesis of asbestosis through effects on inflammation and fibrosis development.
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PMID:Matrix metalloproteinases promote inflammation and fibrosis in asbestos-induced lung injury in mice. 1657 44