Project description:A single-cell transcriptional analysis was performed on GLI1+ stromal cells from the adult murine lung during homeostasis and after fibrotic injury. The goal is to understand the role of GLI1+ stromal cells in lung fibrosis and repair. Whole adult murine lung tissue from two samples were separately dissociated to single cells and subjected to fluorescence activated cell sorting (FACS) to select all live GLI1+ cells. One sample was treated with bleomycin to induce fibrosis and the other was treated with saline as a control. The single cell RNA-sequencing library was generated separately for the bleomycin and saline-treated samples. Cells were sequenced at a depth of ~70,000 reads/cell. We captured approximately 17,700 cells with a median of 2,400 genes detected per cell utilizing a droplet-based barcoding approach to capture single cells for RNA sequencing. After bleomycin-induced fibrosis, we identified a novel "myofibroblast" subset of GLI1 cells that contribute to injury and repair. Injured GLI1 cells also reveal dysregulation in key developmental pathways, including BMP signaling, that contribute to metaplastic repair after fibrotic injury.
Project description:Gli1 is necessary for the progression from chronic gastric inflammation to metaplasia in the stomach. We therefore compared the expression patterns between 6-month H. felis infected WT and Gli1-/- stomachs. Pooled tissue from the gastric fundi of 3 mice per group. Groups are WT, WT + H. felis (6 months), Gli1-/-, and Gli1-/- +H. felis (6 months). All the infected and control mice were obtained from the same experiment.
Project description:Gli1 is necessary for the progression from chronic gastric inflammation to metaplasia in the stomach. We therefore compared the expression patterns between 6-month H. felis infected WT and Gli1-/- stomachs.
Project description:Glioma-associated oncogene homolog-1 (Gli1)-positive resident mesenchymal stem cell-like cells are the predominant source of kidney myofibroblasts in fibrosis, but investigating Gli1-positive myofibroblast progenitor activation is hampered by the difficulty of isolating and propagating primary cultures of these cells. Using a genetic strategy with positive and negative selection, we isolated Kidney-Gli1 (KGli1) cells that maintain expression of appropriate mesenchymal stem cell-like cell markers, respond to hedgehog pathway activation, and display robust myofibroblast differentiation upon treatment with transforming growth factor-β (TGF-β). Coculture of KGli1 cells with endothelium stabilizes capillary formation. Single-cell RNA sequencing (scRNA-seq) analysis during differentiation identified autocrine ligand-receptor pair upregulation and a strong focal adhesion pathway signal. This led us to test the serum response factor inhibitor CCG-203971 that potently inhibited TGF-β-induced pericyte-to-myofibroblast transition. scRNA-seq also identified the unexpected upregulation of nerve growth factor (NGF), which we confirmed in two mouse kidney fibrosis models. The Ngf receptor Ntrk1 is expressed in tubular epithelium in vivo, suggesting a novel interstitial-to-tubule paracrine signaling axis. Thus, KGli1 cells accurately model myofibroblast activation in vitro, and the development of this cell line provides a new tool to study resident mesenchymal stem cell-like progenitors in health and disease.
Project description:GLI1 is a transcription factor correlated to decreased survival in several cancers. We have identified SMARCA2 as a co-regulator that enhances GLI1-mediated transcriptional activity and functions through the C-terminal transcriptional activation domain of GLI1. Central domains including the ATPase motif of SMARCA2 physically interact with GLI1. Evaluation of DNA density indicates GLI1, like SMARCA2, can increase the DNA accessibility with a preference for sites distal to gene transcription start sites and outside the promoter regions (i.e. enhancers). The putative enhancers where accessibility is decreased by the knock down of GLI1 and SMARCA2 are located cis to genes, such as HHIP, that are regulated by GLI1 and implicated in cancer functions. At the putative enhancer for HHIP, the localization of SMARCA2 is at least partially dependent on GLI1’s presence. Understanding this transcriptional regulation by GLI1 and SMARCA2 through altering chromatin accessibility at enhances can provide additional therapeutic targets for cancers dependent on GLI1.
Project description:Increased expression of GLI1 is associated with poor prognosis for some breast cancer subtypes. A conditional transgenic GLI1 expressing mouse model, with or without heterozygous deletion of Trp53, was used to generate and study GLI1 induced mammary gland tumours. Tumour tissue was serially orthotopically transplanted for at least 10 generations in NSG mice.
Project description:Repair-supportive mesenchymal cells (RSMCs) have been recently reported in the context of naphthalene (NA)-induced airway injury and regeneration. These cells transiently express smooth muscle actin (Acta2) and are enriched with platelet-derived growth factor receptor alpha (Pdgfra) and fibroblast growth factor 10 (Fgf10) expression. Genetic deletion of Ctnnb1 (gene coding for beta catenin) or Fgf10 in these cells using the Acta2-Cre-ERT2 driver line after injury (defined as NA-Tam condition; Tam refers to tamoxifen) led to impaired repair of the airway epithelium. In this study, we demonstrate that RSMCs are mostly captured using the Acta2-Cre-ERT2 driver when labeling occurs after (NA-Tam condition) rather than before injury (Tam-NA condition), and that their expansion occurs mostly between days 3 and 7 following NA treatment. Previous studies have shown that lineage-traced peribronchial GLI1+ cells are transiently amplified after NA injury. Here, we report that Gli1 expression is enriched in RSMCs. Using lineage tracing with Gli1Cre-ERT2 mice combined with genetic inactivation of Fgf10, we show that GLI1+ cells with Fgf10 deletion fail to amplify around the injured airways, thus resulting in impaired airway epithelial repair. Interestingly, Fgf10 expression is not upregulated in GLI1+ cells following NA treatment, suggesting that epithelial repair is mostly due to the increased number of Fgf10-expressing GLI1+ cells. Co-culture of SCGB1A1+ cells with GLI1+ cells isolated from non-injured or injured lungs showed that GLI1+ cells from these two conditions are similarly capable of supporting bronchiolar organoid (or bronchiolosphere) formation. Single-cell RNA sequencing on sorted lineage-labeled cells showed that the RSMC signature resembles that of alveolar fibroblasts. Altogether, our study provides strong evidence for the involvement of mesenchymal progenitors in airway epithelial regeneration and highlights the critical role played by Fgf10-expressing GLI1+ cells in this context.