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: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:Lung fibroblasts include several subpopulations. We used single cell RNA sequencing (scRNAseq) to analyze the heterogeneity of lung fibroblasts.
Project description:Skin fibrotic disease representsa major global healthcare burden, characterized by fibroblast hyperproliferation and excessive accumulation of extracellular matrix.Fibroblasts are found to be heterogeneous in multiple fibrotic diseases,but the fibroblast heterogeneity of skin fibrotic diseases remains unknown.In this study, we performed single-cell RNA-seq in keloid, a paradigm of skin fibrotic diseases, andnormal scardermis tissues.Our results indicate thatkeloid and normal scar fibroblasts could be divided into 4 subpopulations: secretory-papillary, secretory-reticular, mesenchymal and pro-inflammatory.The percentage of mesenchymal fibroblast subpopulationincreased significantly in keloid compared to normal scar. Interestingly, we also found increasing mesenchymal fibroblast subpopulation in scleroderma, another skin fibrotic disease.Function studies showed that the mesenchymal fibroblasts promoted collagen synthesis of the other fibroblasts in keloid partiallythrough secreting POSTN. These findings will help us understandskin fibroticpathogenesis in depth,and provided potential target cells for fibrotic diseases therapies.
Project description:Systemic scleroderma (SSc) is an autoimmune disease which results in fibrotic production in the lung. Resultant SSC-pulmonary fibrosis is the main cause of mortality among SSc patients. From high throughput RNAi screening, we uncovered the ubiquitin E3 ligase KLHL42 as a potential pro-fibrotic mediator of TGFb-dependent fibrotic signaling in primary SSc lung fibroblasts. In this analysis, we sought to uncover putative substrates for KLHL42 by comparing SSc lung fibroblasts with control or KLHL42 siRNA prior to TGFb-treatment, lysis, and TUBE precipitation. The resultant pull-down was analyzed with LC-MS/MS.
Project description:p16INK4A inhibits the CDK4/6 kinases and is therefore an important cell cycle regulator. Accumulation of p16INK4A in response to oncogenic transformation leads to cellular senescence and it is therefore frequently lost in cancer. p16INK4A is also known to accumulate under conditions of cellular oxidative stress and therefore could potentially be regulated by redox signaling, which is a form of signal transduction that is mediated by the reversible oxidation of cysteine-thiol side chains in proteins. We found that oxidation of the single cysteine residue in p16INK4A in human cells occurs under relatively mild oxidizing conditions and that this leads to disulfide dependent dimerization. p16INK4A is a well-characterized all alpha-helical protein, but we find that upon cysteine-dependent dimerization, p16INK4A undergoes a dramatic structural rearrangement and forms aggregates that have the typical features of amyloid fibrils, including binding of diagnostic dyes, presence of cross-β sheet structure, and typical dimensions found in electron microscopy. We find that p16INK4A amyloid formation abolishes its function as a CDK4/6 inhibitor in human cells. Taken together, these observations mechanistically link the cellular redox state to the inactivation of p16INK4A through the formation of amyloid fibrils.