Project description:Collagen deposition is a key process during idiopathic pulmonary fibrosis (IPF); however, little is known about the dynamics of collagen formation during disease development. Tissue samples of early stages of human disease are not readily available and it is difficult to identify changes in collagen content, since standard collagen analysis does not distinguish between 'old' and 'new' collagen. Therefore, the current study aimed to (i) investigate the dynamics of new collagen formation in mice using bleomycin-induced lung fibrosis in which newly synthesized collagen was labelled with deuterated water and (ii) use this information to identify genes and processes correlated to new collagen formation from gene expression analysis. Lung fibrosis was induced in female C57BL/6 mice by bleomycin instillation and sacrificed. Animals were sacrificed at 1 to 5 weeks after fibrosis induction. Collagen synthesized during the week before sacrifice was labelled with deuterium by providing mice with deuterated drinking water. After sacrifice, lung tissue was collected for microarray analysis, determination of new collagen formation, and histology. Deuterated water labelling showed a strong increase in new collagen formation already during the first week after fibrosis induction and a complete return to baseline at five weeks. Correlation of new collagen formation data with gene expression data revealed fibrosis specific processes, of which proliferation was an unexpected one. This was confirmed by measuring cell proliferation and collagen synthesis simultaneously using deuterated water incorporation. Furthermore, new collagen formation strongly correlated with gene expression of e.g. elastin, tenascin C, MMP-14, lysyl oxidase, and type V collagen. These data demonstrate, using a novel combination of technologies, that proliferation and extracellular matrix production are correlated to the core process of fibrosis, i.e. the formation of new collagen. In addition, it identified genes directly correlated to fibrosis, thus providing more insight into the aetiology of IPF. Total RNA was obtained from mouse lungs at timepoint 0 as a control (n = 7) or timepoints 1 (n = 7), 2 (n = 6), 3 (n = 6), 4 (n = 6) or 5 (n = 6) weeks after bleomycin-instillation to induce lung fibrosis.
Project description:Bleomycin-induced pulmonary fibrosis in mice mimics major hallmarks of idiopathic pulmonary fibrosis, yet in this model it spontaneously resolves over time. We studied molecular mechanisms of fibrosis resolution and lung repair, focusing on transcriptional and proteomic signatures and the effect of aging. Young (3 months) and old (21 months) mice were treated with Bleomycin or with control saline solution and analyzed transcript and protein expression over 8 weeks (Day 0, 14, 21, 28, 35, 42, 49, 56).
Project description:Collagen deposition is a key process during idiopathic pulmonary fibrosis (IPF); however, little is known about the dynamics of collagen formation during disease development. Tissue samples of early stages of human disease are not readily available and it is difficult to identify changes in collagen content, since standard collagen analysis does not distinguish between 'old' and 'new' collagen. Therefore, the current study aimed to (i) investigate the dynamics of new collagen formation in mice using bleomycin-induced lung fibrosis in which newly synthesized collagen was labelled with deuterated water and (ii) use this information to identify genes and processes correlated to new collagen formation from gene expression analysis. Lung fibrosis was induced in female C57BL/6 mice by bleomycin instillation and sacrificed. Animals were sacrificed at 1 to 5 weeks after fibrosis induction. Collagen synthesized during the week before sacrifice was labelled with deuterium by providing mice with deuterated drinking water. After sacrifice, lung tissue was collected for microarray analysis, determination of new collagen formation, and histology. Deuterated water labelling showed a strong increase in new collagen formation already during the first week after fibrosis induction and a complete return to baseline at five weeks. Correlation of new collagen formation data with gene expression data revealed fibrosis specific processes, of which proliferation was an unexpected one. This was confirmed by measuring cell proliferation and collagen synthesis simultaneously using deuterated water incorporation. Furthermore, new collagen formation strongly correlated with gene expression of e.g. elastin, tenascin C, MMP-14, lysyl oxidase, and type V collagen. These data demonstrate, using a novel combination of technologies, that proliferation and extracellular matrix production are correlated to the core process of fibrosis, i.e. the formation of new collagen. In addition, it identified genes directly correlated to fibrosis, thus providing more insight into the aetiology of IPF.
Project description:Idiopathic pulmonary fibrosis (IPF) is a complex disease involving various cell types. Macrophages are essential in maintenance of physiological homeostasis, wound repair and fibrosis in the lung. Macrophages play a crucial role in repair and remodeling by altering their phenotype and secretory pattern in response to injury. The secretome of induced pluripotent stem cells (iPSC-cm) attenuates injury and fibrosis in bleomycin injured rat lungs. In the current study, we evaluate the effect of iPSC-cm on interstitial macrophage gene expression and phenotype in bleomycin injured rat lungs in vivo. Â iPSC-cm was intratracheally instilled 7 days after bleomycin induced lung injury and assessed 7 days later and single cell isolation was performed. Macrophages were FACS sorted and microarray analysis was performed. We characterized changes in the rat lung interstitial macrophages using transcriptional profiling.
Project description:We conducted fibroblast-specific transcriptome analysis by next generation sequencing in order to investigate qualitative change and activation signatures of lung fibroblasts in bleomycin-induced pulmonary fibrosis. Lung fibroblasts were identified by using reporter mice of collagen-α2(I), in which collagen I-producing fibroblasts were labeled with EGFP. Lungs were dissociated with protease sollution, and single cell suspension were stained with lineage markers (Ter119, CD45, CD31, EpCAM). Lineage- GFP+ cells were sorted out and mRNA was collected. Using serial analysis of gene expression (SAGE) method, we identified 2,973,937 SAGE tags (1,080,798 tags from saline-treated GFP+ fibroblasts and 1,893,139 tags from bleomycin-treated GFP+ fibroblasts). We found that genes related to extracellular matrix construction were highly up-regulated in fibroblasts from belomycin-treated lungs. Moreover, an analysis of mRNA profiles revealed biological functions such as proliferation, invasion, adhesion, and migration were promoted in fibroblasts from bleomycin-treated lung, which recapitulated the role of fibroblasts in the fibrogenesis. These fibroblast-specific gene expression profiles will be important notions in future fibrosis studies. mRNA profiles of Lung fibroblasts from 3 mice at day 14 after saline or bleomycin treatment.
Project description:To analyze the role of HSP27 in bleomycin (BLM)-induced pulmonary fibrosis in vivo, we used TG mice that conventionally overexpressed HSP27. Our previously reported that HSP27 plays an important role in pulmonary fibrosis. In mice overexpressing HSPB1, BLM-induced fibrotic regions and collagen deposits were increased compared with those in control BL6 mice. Following intratracheal treatment of BLM, the HSP25 TG mice showed an abundance of mononuclear and neutrophils cells in the alveoli, greater destruction of alveolar septa, intra-alveolar hyaline membrane formation, and a marked increase in collagen deposition compared with control BL6 mice.
Project description:Idiopathic pulmonary fibrosis (IPF) is a progressive, irreversible fibrotic disease of the distal lung alveoli that culminates in respiratory failure and reduced lifespan. Unlike normal lung repair in response to injury, IPF is associated with the accumulation and persistence of fibroblasts and myofibroblasts and continued production of collagen and other extracellular matrix (ECM) components. Prior in vitro studies have led to the hypothesis that the development of resistance to Fas-induced apoptosis by lung fibroblasts and myofibroblasts contibributes to their accumulation in the distal lung tissues of IPF patients. Here, we test this hypothesis in vivo in the resolving model of bleomycin-induced pulmonary fibrosis in mice. Using genetic loss-of-function approaches to inhibit Fas signaling in fibroblasts, novel flow cytometry strategies to quantify lung fibroblast subsets and transcriptional profiling of lung fibroblasts by bulk and single cell RNA-sequencing, we show that Fas is necessary for lung fibroblast apoptosis during homeostatic resolution of bleomycin-induced pulmonary fibrosis in vivo. Furthermore, we show that loss of Fas signaling leads to the persistence and continued pro-fibrotic functions of lung fibroblasts. Our studies provide novel insights into the mechanisms that contribute to fibroblast survival, persistence and continued ECM deposition in the context of IPF and how failure to undergo Fas-induced apoptosis prevents fibrosis resolution.
Project description:Intratracheal application of bleomycin is known to induce inflammatory and fibrotic reactions in the lung within a short period of time and histological features include infiltration of inflammatory cells, collagen deposition and obliteration of alveolar spaces. Because some of these features are found in patients with idiopathic pulmonary fibrosis (IPF), the bleomycin-induced lung fibrosis animal model is commonly used. However, exploratory treatments that were successfully used in this animal model and progressed to clinical trials lacked significant efficacy in humans. Here, the bleomycin-induced rat lung fibrosis model was studied using whole genome expression data that was collected at various time points and the relevance to human disease was evaluated through comparison with whole genome expression data from IPF patient-derived lung biopsies. The highest gene expression correlation between both species was observed in animals 7 days after bleomycin instillation. These gene expression signatures helped to identify a set of twelve novel disease-relevant translational gene markers that were able to separate IPF patients from controls. Furthermore, three Wnt/-catenin pathway-related genes that belong to this translational gene marker set showed, together with clinical diffusing capacity of the lung for carbon monoxide (DLCO) measurements, the potential to stratify IPF patients according to disease severity. Pirfenidone attenuated a subset of the translational gene markers in the bleomycin-induced fibrosis model, in particular those related to Wnt/-catenin-signaling. This novel translational gene marker panel offers improved possibilities to evaluate disease-modifying efficacy of novel therapeutic concepts in the bleomycin-induced rat lung fibrosis model and could be applied as a diagnostic and prognostic tool for IPF patient care. Comparison of bleomycin-treated and control rats after 3 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 6 weeks and 8 weeks; 5 animals per group
Project description:Bleomycin-induced pulmonary fibrosis in mice mimics major hallmarks of idiopathic pulmonary fibrosis, yet in this model it spontaneously resolves over time. We studied molecular mechanisms of fibrosis resolution and lung repair, focusing on transcriptional and proteomic signatures and the effect of aging. Old mice showed delayed and incomplete lung function recovery 8 weeks after Bleomycin instillation. This shift in structural and functional repair in old Bleomycin-treated mice was reflected in a temporal shift in gene and protein expression. We reveal gene signatures and signaling pathways which underpin the lung repair process.