Project description:Background and objective: The role of bronchiolar epithelial cells in the pathogenesis of pulmonary fibrosis has not been addressed. We previously demonstrated that DNA damage was found in bronchiole at early phase, and subsequently extended to alveolar cells at later phase in bleomycin-induced pulmonary fibrosis in mice. Club cells are progenitor cells for bronchiole, and are recognized to play protective roles against lung inflammation and damage. The aim of the study was to elucidate the role of club cells in the development of pulmonary fibrosis. Methods: C57BL/6J mice were received naphthalene intraperitoneally at day -2 to deplete club cells, and were given intratracheal bleomycin or vehicle at day 0. Lung tissues were obtained at day 1, 7, and 14, and bronchoalveolar lavage was performed at day 14. Gene expression was analysed from bronchiolar ephithelial cells sampled by laser captured microdissection at day 14. Results: Surprisingly, naphthalene-induced club cell depletion protected mice from bleomycin-induced lung injury and fibrosis. We conclude that club cells are involved in the development of lung injury and fibrosis.
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 previously showed that pericyte-like cells derived from the FoxD1-lineage contribute to myofibroblasts following bleomycin-induced lung injury. However, their functional significance in lung fibrosis remains unknown. In this study, we used a model of lung pericyte-like cell ablation to test the hypothesis that pericyte-like cell ablation attenuates lung fibrosis in bleomycin-induced lung injury. Methods: Lung fibrosis was induced by intratracheal instillation of bleomycin. To ablate pericyte-like cells in the lung, diphtheria toxin (DT) was administered to Foxd1-Cre;Rosa26-iDTR mice at two different phases of bleomycin-induced lung injury. For early ablation, we co-administered bleomycin with DT and harvested mice at days 7 and 21. To test the effect of ablation after acute injury, we delivered DT 7 days after bleomycin administration. We assessed fibrosis by lung hydroxyproline content and semiquantitative analysis of picrosirius red-staining. We performed bronchoalveolar lavage to determine cell count and differential. We also interrogated genome-wide mRNA expression at day 7 post injury in whole lung RNA. We focused on the following cell populations for the transcriptional profiling experiments: FoxD1-derived+/Coll-GFP– pericytes (Peri), FoxD1-derived+/Coll-GFP+ pericytes (PeriFibro), and FoxD1-derived–/Coll-GFP+ stromal fibroblasts (Fibro).Results: Compared to DT-insensitive littermates where pericyte-like cells were not ablated, DT-sensitive animals exhibited no difference in fibrosis at day 21 both in the early and late pericyte ablation models. However, early ablation of pericytes reduced acute lung inflammation, as indicated by decreased inflammatory cells. Our data confirm a role for pericytes in regulating pulmonary inflammation in early lung injury.
Project description:Rationale: The role of club cells in the pathology of Idiopathic Pulmonary Fibrosis IPF is not well understood. PDIA3, an endoplasmic reticulum (ER) based redox chaperone catalyzes the cysteine disulfide bonds (-S-S-) in various fibrosis-related proteins; however, mechanisms of action of PDIA3 in pulmonary fibrosis is not fully elucidated. Objectives: To examine the role of club cells and PDIA3 in the pathogenesis of pulmonary fibrosis (PF) and therapeutic potential of inhibition of PDIA3 in PF. Methods: The impact of PDIA3 and aberrant club cells in PF was studied by retrospective analysis of human transcriptome data from LGRC, and specific deletion and inhibition of PDIA3 in club cells and blocking Osteopontin (SPP1) downstream of PDIA3 in mice. Measurements and Main Results: The PDIA3 along with club cell secretory protein (SCGB1A1 or CCSP) signatures are upregulated in IPF compared to control patients, and PDIA3 increases correlate with a decrease in lung function in IPF patients. The Bleomycin (BLM) model of PF showed increases in aberrant CCSP and PDIA3 positive cells in the lung parenchyma. Ablation of Pdia3, specifically in CCSP cells, decreases CCSP cells along with PF in mice. The therapeutic administration of a PDI inhibitor LOC14 reversed the BLM-induced CCSP cells and PF in mice. The proteomic screen of the PDIA3 partners revealed SPP1 as a major interactor in PF. Blocking SPP1 attenuated the development of PF in mice. Conclusions: Collectively, this study demonstrates a new relationship of club cells, with PDIA3, SPP1, and a putative pathological function of club cells in pulmonary fibrosis.
Project description:The molecular mechanisms of lung injury and fibrosis are incompletely understood. microRNAs (miRNAs) are crucial biological regulators by suppression of their target genes and are involved in a variety of pathophysiologic processes. To gain insight into miRNAs in the regulation of lung fibrosis, total RNA was isolated from lung samples harvested at different days after bleomycin treatment, and miRNA array was performed thereafter. miRNAs expressed in lungs with bleomycin treatment at different time points were compared to miRNAs expressed in lungs without bleomycin treatment, resulting in 161 miRNAs differentially expressed. Furthermore, miRNA expression patterns regulated in initial and late periods after bleomycin were identified. Target genes were predicted in silico for differentially expressed miRNAs, including miR-7f, miR-7g, miR-196b, miR-16, miR-195, miR-25, miR-144, miR-351, miR-34a, miR-499, miR-704, miR-717, miR-10a, miR-211, miR-34a, miR-367 and miR-21, and then cross-referenced to molecular pathways including apoptosis, Wnt, Toll-like receptor, and TGF-? signaling, which are involved in different pathological phenotypes such as apoptosis, inflammation, and fibrosis. Our study demonstrated relative abundance of miRNA levels in bleomycin-induced lung fibrosis. The miRNAs and their potential target genes identified herein contribute to the understanding of the complex transcriptional program of lung fibrosis. Under anesthesia, 2.5 U/kg bleomycin dissolved in sterile PBS was administered via trachea as previously described. Lung tissues were harvested at the time point of day 0, 3, 7, 14, and 21 post bleomycin challenges. 3 sample in specific time point, except for day 14 where nday14 = 2.
Project description:We applied next-generation sequencing to investigate the gene expression profiles in mouse alveolar epithelial cells (AECs). We identified a number of differentially regulated genes in the AECs of mice with bleomycin induced pulmonary fibrosis and LPS induced acute lung injury.
Project description:Fibrosing interstitial lung disease (fILD) is a fatal fibrotic lung disease with limited therapeutic options and no effective therapeutic strategies to reverse pulmonary fibrosis. Here, we found that PTX3 is upregulated in the lungs of bleomycin-treated mice and fILD patients. Lung injury and fibrosis were significantly attenuated in inducible conditional Ptx3-deficient mice in response to bleomycin treatment. Moreover, we dissected mechanistic insights into PTX3/CD44-dependent fibrotic pathways and effectors in lung myofibroblast activation and collagen production. Importantly, αPTX3i disrupts the interaction of PTX3 and CD44 and effectively attenuated bleomycin-treated lung injury and fibrosis in vivo and myofibroblast activation in vitro. Our study provides new insight into the regulation of PTX3 in pulmonary fibrosis and a potential target for developing future novel therapy for fILDs.
Project description:The most preclinical used in vivo model to study lung fibrosis is the bleomycin-induced lung fibrosis model in 2-3-month-old mice. Although this model resembles key aspects of idiopathic pulmonary fibrosis (IPF), there are limitations in its predictability for the human disease. One of the main differences is the juvenile age of animals that are usually used in experiments, resembling humans of around 20 years. Because IPF patients are usually older than 60 years, aging appears to play an important role in the pathogenesis of lung fibrosis. We here compared young (3 months) and old (21 months) mice 21 days after intratracheal bleomycin instillation.
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: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).