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Bleomycin-induced Pulmonary Fibrosis (bleomycin-induced + pulmonary_fibrosis)
Selected AbstractsSmad3 as a mediator of the fibrotic responseINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 2 2004Kathleen C. Flanders Summary Transforming growth factor-, (TGF-,) plays a central role in fibrosis, contributing to the influx and activation of inflammatory cells, the epithelial to mesenchymal transdifferentiation (EMT) of cells and the influx of fibroblasts and their subsequent elaboration of extracellular matrix. TGF-, signals through transmembrane receptor serine/threonine kinases to activate novel signalling intermediates called Smad proteins, which modulate the transcription of target genes. The use of mice with a targeted deletion of Smad3, one of the two homologous proteins which signals from TGF-,/activin, shows that most of the pro-fibrotic activities of TGF-, are mediated by Smad3. Smad3 null inflammatory cells and fibroblasts do not respond to the chemotactic effects of TGF-, and do not autoinduce TGF-,. The loss of Smad3 also interferes with TGF-,-mediated induction of EMT and genes for collagens, plasminogen activator inhibitor-1 and the tissue inhibitor of metalloprotease-1. Smad3 null mice are resistant to radiation-induced cutaneous fibrosis, bleomycin-induced pulmonary fibrosis, carbon tetrachloride-induced hepatic fibrosis as well as glomerular fibrosis induced by induction of type 1 diabetes with streptozotocin. In fibrotic conditions that are induced by EMT, such as proliferative vitreoretinopathy, ocular capsule injury and glomerulosclerosis resulting from unilateral ureteral obstruction, Smad3 null mice also show an abrogated fibrotic response. Animal models of scleroderma, cystic fibrosis and cirrhosis implicate involvement of Smad3 in the observed fibrosis. Additionally, inhibition of Smad3 by overexpression of the inhibitory Smad7 protein or by treatment with the small molecule, halofuginone, dramatically reduces responses in animal models of kidney, lung, liver and radiation-induced fibrosis. Small moleucule inhibitors of Smad3 may have tremendous clinical potential in the treatment of pathological fibrotic diseases. [source] Effects of Th2 pulmonary inflammation in mice with bleomycin-induced pulmonary fibrosisRESPIROLOGY, Issue 6 2008Hirokuni HIRATA Background and objective: Leucocytes, especially lymphocytes and neutrophils, as well as alveolar macrophages, that infiltrate into the lung are involved in the development of pulmonary fibrosis. However, the role of T helper (Th)2-type inflammation, mediated by Th2 cells and eosinophils, in fibrosis remains unknown. Transgenic mice deficient in the transcriptional repressor, Bcl6, display an attenuation of Th2 cytokine production. We studied the effects of Th2-type pulmonary inflammation on bleomycin-induced pulmonary fibrosis using Bcl6 transgenic mice. Methods: Bleomycin was administered to ovalbumin (OVA)-sensitized Bcl6 transgenic and wild-type mice by intratracheal instillation during sequential OVA antigen challenge. Concentrations of transforming growth factor-,1 in the BAL fluid were measured 2 weeks after bleomycin administration. At the same time lung tissue was examined histopathologically, and homogenized to assess collagen levels and Th1/Th2 cytokine mRNA expression. Results: Although OVA-sensitized, bleomycin-treated Bcl6 transgenic mice had markedly lower numbers of eosinophils in both BAL and lung tissue compared with OVA-sensitized, bleomycin-treated wild-type mice, the development of pulmonary fibrosis in response to bleomycin was similar in Bcl6 transgenic mice and wild-type mice. Conclusion: These results suggest that Th2-dominant inflammation in the lung is not essential for the development of bleomycin-induced pulmonary fibrosis. [source] C-C chemokine receptor 2 (CCR2) deficiency improves bleomycin-induced pulmonary fibrosis by attenuation of both macrophage infiltration and production of macrophage-derived matrix metalloproteinasesTHE JOURNAL OF PATHOLOGY, Issue 5 2004Toshiyuki Okuma Abstract 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. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source] A novel inhibitor of Smad-dependent transcriptional activation suppresses tissue fibrosis in mouse models of systemic sclerosisARTHRITIS & RHEUMATISM, Issue 11 2009Minoru Hasegawa Objective Tissue fibrosis is a major cause of morbidity and mortality in systemic sclerosis (SSc), and an increasing number of promising molecular targets for antifibrotic therapies have been described recently. Transforming growth factor , (TGF,) is well known to be the principal factor that leads to tissue fibrosis. The present study was undertaken to investigate the ability of HSc025, a novel small compound that antagonizes TGF,/Smad signaling through the activation of nuclear translocation of Y-box binding protein 1, to prevent tissue fibrosis in vitro or in mouse models of SSc. Methods Human dermal fibroblasts were exposed to HSc025 at various concentrations in the presence of TGF,, and levels of collagen or fibronectin expression were determined. HSc025 (15 mg/kg/day for 14 days) was administered orally to tight skin mice and to mice with bleomycin-induced pulmonary fibrosis. Improvement of tissue fibrosis was evaluated by histologic or biochemical examination in each model. Results Pretreatment with HSc025 prevented Smad-dependent promoter activation, in a dose-dependent manner; however, HSc025 had no effect on TGF,-induced phosphorylation of Smad3. The inhibitory effects of HSc025 on TGF,-induced collagen or fibronectin expression were also confirmed in vitro. Orally administered HSc025 significantly reduced hypodermal thickness and hydroxyproline content in tight skin mice, and markedly decreased the histologic score and hydroxyproline content in the lungs of bleomycin-treated mice. Conclusion These results demonstrate that HSc025 is a novel inhibitor of TGF,/Smad signaling, resulting in the improvement of skin and pulmonary fibrosis. Orally available HSc025 might therefore be useful in the treatment of SSc. [source] In vitro tracheal hyperresponsiveness to muscarinic receptor stimulation by carbachol in a rat model of bleomycin-induced pulmonary fibrosisAUTONOMIC & AUTACOID PHARMACOLOGY, Issue 3 2006J. Barrio Summary 1 Bleomycin-induced lung injury is widely used as an experimental model to investigate the pathophysiology of pulmonary fibrosis but the alterations in the pharmacological responsiveness of airways isolated from bleomycin-exposed animals has been scarcely investigated. The aim of this study was to examine the in vitro tracheal responses to muscarinic receptor stimulation with carbachol in a rat bleomycin model. 2 Concentration,response curves to carbachol (10 nm to 0.1 mm) were obtained in tracheal rings isolated from Sprague,Dawley rats 14 days after endotracheal bleomycin or saline. The intracellular calcium signal in response to carbachol (10 ,m) was measured by epifluorescence microscopy using fura-2 in primary cultures of tracheal smooth muscle cells from bleomycin- and saline-exposed rats. Circulating plasma tumour necrosis factor (TNF)- ,/interleukin (IL)-1, levels were measured by enzyme-linked immunosorbent assay. 3 Maximal contraction in response to carbachol was significantly greater in tracheal rings from bleomycin-exposed rats compared with controls (15.8 ± 1.3 mN vs. 11.8 ± 1.4 mN; n = 19, P < 0.05). 4 Carbachol (10 ,m) elicited a transient increase of intracellular calcium with greater increment in tracheal smooth muscle cells from bleomycin-exposed rats compared with controls (372 ± 42 nmvs. 176 ± 20 nm; n = 7, P < 0.01). 5 Circulating plasma levels of TNF- ,/IL-1, were augmented in bleomycin-exposed rats compared with controls. Tissue incubation with TNF- , (100 ng ml,1)/IL-1, (10 ng ml,1) increased in vitro tracheal responsiveness to carbachol. 6 In conclusion, tracheal contraction in response to muscarinic receptor stimulation with carbachol was increased in bleomycin-exposed rats. This in vitro cholinergic hyperresponsiveness may be related to the augmented levels of inflammatory cytokines in bleomycin-exposed rats. [source] Effects of fish oil treatment on bleomycin-induced pulmonary fibrosis in miceCELL BIOCHEMISTRY AND FUNCTION, Issue 5 2006Luciano Paulino Silva Abstract Bleomycin is an antibiotic used to treat a variety of neoplasms. A major side-effect of bleomycin therapy is the induction of an intense inflammatory response that develops into pulmonary fibrosis. Several studies have shown that certain polyunsaturated fatty acids found in fish oil reduce the inflammatory response in vivo. Fish oil has been employed for the treatment of several pathologies such as glomerulonephritis, cardiovascular diseases, rheumatoid arthritis, and even as an adjuvant in cancer therapy. This study examined the effects of fish oil treatment on the development of bleomycin-induced pulmonary fibrosis. Mice were intraperitoneally treated with bleomycin or with saline daily for 10 days, and 15 days after the last injection they started to receive fish oil by gavage for 14 days. The lungs were processed for light microscopy, biochemical and immunohistochemical investigations. Fish oil did not prevent the development of pulmonary fibrosis after the injury as shown by light microscopy, cytokines immunohistochemical analysis, TBARS content and protein levels in the lung. In addition however, fish oil itself induced a slight inflammatory process in the lung, as observed by the increase in cellularity, vasodilatation in the lung parenchyma, TBARS content, and a slight increase in the lung protein content. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||