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:Expression analysis of migrating and non-migrating mesenchymal stromal cells (MSC) in fetal bone marrow Keywords: fetal bone marrow, mesenchymal stromal cells, migration, gene expression, genomics Three biological replates for both migrating and non-migrating mesenchymal stromal cells (MSC) in fetal bone marrow
Project description:Aberrant epithelial reprogramming can induce metaplastic differentiation at sites of tissue injury that culminates in transformed barriers composed of scar and metaplastic epithelium. While the plasticity of epithelial stem cells is well characterized, the identity and role of the niche has not been delineated in metaplasia. Here, we show that Gli1+ mesenchymal stromal cells (MSCs), previously shown to contribute to myofibroblasts during scarring, promote metaplastic differentiation of airway progenitors into KRT5+ basal cells. During fibrotic repair, Gli1+ MSCs integrate hedgehog activation signalling to upregulate BMP antagonism in the progenitor niche that promotes metaplasia. Restoring the balance towards BMP activation attenuated metaplastic KRT5+ differentiation while promoting adaptive alveolar differentiation into SFTPC+ epithelium. Finally, fibrotic human lungs demonstrate altered BMP activation in the metaplastic epithelium. These findings show that Gli1+ MSCs integrate hedgehog signalling as a rheostat to control BMP activation in the progenitor niche to determine regenerative outcome in fibrosis.
Project description:Gastric mucosal homeostasis is maintained by tissue-resident stem cells. Following mucosal injury, both stem cells and a subset of differentiated cell types contribute to regeneration, coinciding with characteristic pathological changes such as atrophic gastritis and metaplasia. To comprehensively understand the cellular dynamics involved in this process, we performed single-cell and spatial transcriptomics using newly generated transgenic mice. In humans, gastric chief cell loss precedes parietal cell loss during the progression of atrophy and metaplasia. In mice, selective ablation of chief cells induces parietal cell loss and accelerates metaplasia development, validating the causal relationship underlying the decrease of these two lineages. Single-cell analysis confirmed robust stemness activity and metaplastic changes in neck cell clusters following either chief or parietal cell ablation, and lineage-tracing experiments revealed that neck cells serve as a source of metaplasia and regeneration. Mechanistically, mucosal injury recruits IL-1-expressing myeloid cells, which stimulates NRG1 production in stromal fibroblasts, leading to mucosal proliferation and regeneration mediated by activated neck cells. These findings highlight the plasticity and facultative stem cell function of gastric neck cells, which play a critical role in mucosal homeostasis and disease progression.
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.