Project description:We studied the role of p16INK4a+ fibroblasts in lung fibrosis. We used single cell RNA seq (scRNA-seq) to characterize p16INK4a+ fibroblasts in fibrotic lung.
Project description:Pulmonary fibrosis develops as a consequence of environmentally induced lung injury and/or an inherent disease susceptibility causing fibroblast activation, proliferation and extracellular matrix deposition. The study was undertaken to characterise global gene expression in pulmonary fibroblasts to better understand the mechanisms underlying the fibrotic fibroblast phenotype. Gene expression was evaluated in lung fibroblasts derived from ten controls (normal periphery of resected tumor), open lung biopsies from eight patients with interstitial lung disease associated with systemic sclerosis (fibrotic non specific interstitial pneumonia pattern on biopsy), and from three patients with usual interstitial pneumonia. Lung fibroblasts were grown to confluence in DMEM with 10% fetal calf serum. At confluence, lung fibroblasts were serum-deprived for 44 hours in the presence of fibroblast growth medium with the addition of 0.1% bovine serum albumin (Sigma).
Project description:The activation and accumulation of lung fibroblasts, leading to excessive extracellular matrix (ECM) deposition, is a pathogenic hallmark of Idiopathic Pulmonary Fibrosis (IPF), a lethal and currently incurable disease. The collagen-rich fibrotic ECM perpetuates fibroblast activation and accumulation, which includes the promotion of podosome formation and ECM invasion. Proteoglycans (PGs), a significant component of the interstitial ECM, fine-tune the overall tissue architecture determined by fibrous proteins and regulate several ECM-controlled signalling pathways. In this report, increased expression of Versican (VCAN ), a multifunctional PG, was detected in human and mouse pulmonary fibrosis, predominantly in monocytic cells and fibroblasts. Genetic reduction of Vcan expression in mice promoted collagen expression and modulated pulmonary ECM composition and structure, exacerbating pulmonary fibrosis and delaying its resolution. Reduced ECM Vcan levels resulted in longer, thicker, and more tangled collagen fibrils, which stimulated podosome formation in fibroblasts and their ECM invasion. Moreover, the decrease of Vcan in the ECM and the ensuing reorganisation stimulated Tenascin-C (TNC) expression from fibroblasts, which was further shown to be a potent, TLR4-dependent, autologous podosome inducer, promoting ECM invasion. Thus, Vcan expression from fibroblasts serves as an autologous fibrotic brake, controlling the underlying ECM composition, structure and mechanotransduction, and suppressing fibroblast invasion and pulmonary fibrosis.
Project description:Runx1 emerged as a transcription factor that was potentially regulating fibroblast activation and memory following intratracheal bleomycin injury. In order to examine this, fibroblasts were lineage traced and collected following bleomyicn induced fibrosis at the peak fibrotic time point, Day 14, and at the time of fibrotic recovery, Day 56. Runx1 ChIPseq was performed to assess Runx1 binding in regions of genes known to be associated with fibrosis.
Project description:Pulmonary fibrosis develops as a consequence of environmentally induced lung injury and/or an inherent disease susceptibility causing fibroblast activation, proliferation and extracellular matrix deposition. The study was undertaken to characterise global gene expression in pulmonary fibroblasts to better understand the mechanisms underlying the fibrotic fibroblast phenotype.
Project description:Progressive tissue fibrosis is a major cause of morbidity, and idiopathic pulmonary fibrosis (IPF) is a terminal illness characterized by unremitting matrix deposition in the lung with very limited choice of therapies. The imcomplete understanding of the mechanisms of progressive fibrosis curbs the progress in therapeutics development. Of which, the origin of fibrotic fibroblasts has been poorly defined during the pathogenesis of tissue fibrosis. Here, we fate-mapped a early embryonic transcription factor T-box gene 4 (Tbx4)-derived mesenchymal progenitors in injured adult lung and found that Tbx4+ lineage cells are the major source of myofibroblasts. The ablation of Tbx4+ cells or disruption of Tbx4 signaling attenuated lung fibrosis in bleomycin injury model in mice in vivo. Furthermore, Tbx4+ fibroblasts are more invasive and the regulation of fibroblast invasiveness by Tbx4 is through mediating hyaluronan synthase 2 (HAS2). This study identified a major mesenchymal transcription factor driving the development of fibrotic fibroblasts during lung fibrosis. Understanding the origin, signaling, and functions of these fibroblasts would prove pivotal in the development of therapeutics for patients with progressive fibrotic diseases. We used microarrays to detail the gene expression of Tbx4 and non-Tbx4 cultured fibroblasts.
Project description:KLF4 was overexpressed by adenoviral infection in primary human SSc lung fibroblasts, RNA and protein were extracted, RNA sequencing and differential expression analysis "ad-KLF4 vs ad-Null" were performed to obtain gene and systems level analyses. Markers of alveolar, inflammatory and fibrotic fibroblasts were validated by qPCR and immunoblotting. Our results show that overexpression of KLF4 in SSc fibroblasts initiated dedifferentiation.